Steel Times International September 2021

ROLLING

INNOVATIONS

SPECIAL STEELS

PERSPECTIVES Q&A

Digital integration of hot and cold rolled strip at Marcegaglia.

The latest global contracts and new products news for the steel industry.

How molybdenum alloying can alleviate hydrogen-induced failure.

We talk to Chris Woodhead, managing director of Advanced Actuators.

Since 1866

www.steeltimesint.com September 2021 - Vol.45 No6

STEEL TIMES INTERNATIONAL – September 2021 – Vol.45 No6

25 YEARS OF COJET TECHNOLOGY FOR THE EAF STI Cover.indd 1

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Leading partner in the world of metals

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10.09.20 14:01

CONTENTS – SEPTEMBER 2021

ROLLING

INNOVATIONS

SPECIAL STEELS

PERSPECTIVES Q&A

Digital integration of hot and cold rolled strip at Marcegaglia.

The latest global contracts and new products news for the steel industry.

How molybdenum alloying can alleviate hydrogen-induced failure.

We talk to Chris Woodhead, managing director of Advanced Actuators.

Since 1866

1

2 Leader 4 News round-up The latest global news.

30 Special steels: IMOA Delayed cracking – a serious challenge for ultra-high strength steel.

12 Innovations Contracts and products news.

33 Rolling Integration and digitalization.

19 USA update Imports and production not yet at pre-pandemic levels.

43 EAF 25 years of CoJet technology.

www.steeltimesint.com September 2021 - Vol.45 No6

STEEL TIMES INTERNATIONAL – September 2021 – Vol.45 No6

Front cover: Linde

25 YEARS OF COJET TECHNOLOGY FOR THE EAF

EDITORIAL Editor Matthew Moggridge Tel: +44 (0) 1737 855151 matthewmoggridge@quartzltd.com Consultant Editor Dr. Tim Smith PhD, CEng, MIM Production Editor Annie Baker Advertisement Production Martin Lawrence SALES International Sales Manager Paul Rossage paulrossage@quartzltd.com Tel: +44 (0) 1737 855116 Sales Director Ken Clark kenclark@quartzltd.com Tel: +44 (0) 1737 855117 Managing Director Tony Crinion tonycrinion@quartzltd.com Tel: +44 (0) 1737 855164 Chief Executive Officer Steve Diprose

23 Latin America update Chilean steel is doing well.

48 Coating Responsive control for hot dip galvanizing.

26 India update Infrastructure drives steel recovery.

52 Perspectives Q&A: Advanced Actuators No compromise on quality, says MD.

28 Iron ore Marampa’s best-quality African ore.

55 History Resita – post World War One.

SUBSCRIPTION Elizabeth Barford Tel +44 (0) 1737 855028 Fax +44 (0) 1737 855034 Email subscriptions@quartzltd.com Steel Times International is published eight times a year and is available on subscription. Annual subscription: UK £195.00 Other countries: £270.00 2 years subscription: UK £350.00 Other countries: £485.00 ) Single copy (inc postage): £45.00 Email: steel@quartzltd.com Published by: Quartz Business Media Ltd, Quartz House, 20 Clarendon Road, Redhill, Surrey, RH1 1QX, England.

Tel: +44 (0)1737 855000 Fax: +44 (0)1737 855034 www.steeltimesint.com Steel Times International (USPS No: 020-958) is published monthly except Feb, May, July, Dec by Quartz Business Media Ltd and distributed in the US by DSW, 75 Aberdeen Road, Emigsville, PA 17318-0437. Periodicals postage paid at

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LEADER

Basking in the glow of positive energy

Matthew Moggridge Editor matthewmoggridge@quartzltd.com

STI Half Page Horizontal Ad - Water Footprint.indd September/October 2021

leader.indd 1

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I was standing in the office kitchen, mask on, clasping a cup of tea while chatting with fellow editors about leader writing. I spoke of how I often find myself staring at a blank page, like now, wondering what to write.

I am looking forward to the day when we can all attend conferences again without worrying about COVID-19. I want to sit and listen to live presentations about the state of the steel industry and what is being done to solve the problems that exist. I look forward to meeting colleagues and discussing the industry face-to-face and not through a computer screen via earphones.

Despite the problems we are all facing, however, there are so many different things happening within the global steel industry at present, and it’s nice (for a change) to bask in the glow of so much positive energy. In Japan, for example, JFE, Nippon Steel and Kobe Steel are all looking at big profits recoveries, thanks to rising prices, one-off valuation gains and strong overseas markets. In India, JSW is reporting a capacity utilisation rate increase of 1% in July 2021 compared with the same period last year, and in Austria,

voestalpine has reported positive Q1 performances across most market sectors.

It’s good to see steelmakers receiving awards too, so my congratulations go out to Jindal Stainless (Hisar) Ltd for winning a coveted International Safety Award from the world renowned British Safety Council.

The award recognises Jindal’s health, safety and well-being management.

These days, of course, you would be hard-pressed to get through the day without encountering the phrases ‘climate change’ and ‘energy efficiency’ or the word ‘sustainability’. In a nutshell, everybody is ‘at it’ in some way or other, but the big story for the global steel industry is coming out of Sweden. SSAB, a leading Swedish steelmaker, has manufactured the first fossil-free steel in the world and has delivered it to a customer. This is massive news and marks a true milestone for the HYBRIT initiative, a joint venture between SSAB, LKAB and Vattenfall. HYBRIT stands for Hydrogen Breakthrough Ironmaking Technology and, talking as we were about basking in the glow of positive energy, there must also be some huge sighs of relief as the industry realises that making fossil-free steel is no longer a pipedream.

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4 NEWS ROUND-UP

• Lots going on at Nucor: the company has completed its $1 billion acquisition of two insulated metal panel brands (Centria and Metl-Span) from Cornerstone Building Brands, and is pushing ahead with its $164 million tube mill in Kentucky, USA. Centria and Metl-Span, it is claimed, allow the American steel giant to service high-end architectural applications and the cold storage and warehousing markets.

Source: Herald Sun, 11 August 2021

• An article by Argus claims that most US steel buyers believe that the US $1 trillion infrastructure bill will increase demand for plate products and rebar, which are traditionally used in bridge and road construction respectively. However, projects that aren’t “shovel ready” are unlikely to start consuming steel until 2022.

Source: ArgusMedia, 11 August 2021

• Indian steelmaker JSW has reported a 1% increase in its capacity utilisation rate, according to Mysteel Global.

The July 2021 rate was 92%, up 1% on the 91% rate recorded the previous month.

Source: Mysteel Global, 12 August 2021

• Austrian steelmaker voestalpine has reported positive Q1 2021 performances across all market sectors with the exception of aerospace.

Revenues were 45.6% up year-on-year from 2.4 billion Euros (Q1 2020/21) to 3.5 billion Euros (Q1 2021/22). In the current business year’s Q1, voestalpine’s EBITDA increased by 242% from 158 million Euros to 540 million Euros.

Source: Metal AM, 11 August 2021

• Two big US integrated mill operators, US Steel and Cleveland Cliffs, are taking blast furnaces off line. US Steel’s 1.36Mt/ yr furnace no.6 at Gary, Indiana, will be out of action for 38 days starting 30 September, while Cleveland Cliffs' No 7 blast furnace at its Indiana Harbour facility will be down for between 45-60 days. Nucor is planning to close its 1.6Mt/yr electric arc furnace at its Gallatin, KY, flat-rolled mill for around one month starting at the end of November.

Source: Argus Media, 12 August 2021

• Norma B Clayton has been elected on to the board of directors of Nucor Corporation. Ms Clayton is currently chair of the board of trustees of Tuskegee University and has worked as vice president for learning, training and development at Boeing (2007 to 2016). Clayton has also held senior positions at General Motors, Lockheed Martin and General Electric Company.

Source: MDM.com, 13 August 2021

• Japanese steelmakers are looking at big profits recovery as steel demand surges, claims an online media report. JFE has doubled its annual net profit forecast and there have been similar upgrades by Nippon Steel and Kobe Steel, it is reported.

Rising prices, one-off valuation gains on materials inventories and strong overseas markets are three reasons given by JFE’s executive VP, Masashi Terahata for doubling the company’s profit estimate. Source: Market Screener, 12 August 2021 September 2021

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• Transforming waste product into steel with the help of a $10 million loan from the bank (Banco Bilbao Vizcaya Argentaria) is what Gerdau subsidiary Siderperu is doing. The company refers to the loan as the first ‘sustainable’ credit line, designed to promote the importation, transformation and elimination of solid wastes, like scrap, for auto parts, home appliances and residues from products used in construction. A Clean Product Agreement has been signed with the Peruvian Ministry of Environment and a similar agreement has been agreed with the Ministry of Production to reduce solid waste output.

Source: Steel Orbis, 13 August 2021

• Commercial Metals Company, one of the largest producers of rebar in the USA, has awarded an EAF revamp project to the German company Badische Stahlwerke Engineering (BSE). CMC has nine melting locations, including one in Poland, all are EAF installations producing over 5Mt of long steel products.

Source: Badische Stahlwerke Engineering, 17 August 2021 www.steeltimesint.com

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NEWS ROUND-UP

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• Indian steelmaker Jindal Stainless (Hisar) Ltd has been awarded the ‘International Safety Award 2021 Merit’ by the UK-based British Safety Council, the world’s leading guide for health, safety and well-being management, for the second time in a row. The award recognises commitment to exemplary health, safety and well-being management.

Source: Jindal Stainless (Hisar) Ltd, 18 August 2021

• The Russian Novorossiysk Rolling Plant LLC has awarded Italian plant builder Danieli with an order for a new wire rod mill plant, to be installed in Shakhty in the Rostov region of Russia. The 600kt/ yr plant will be erected on a greenfield site and produce coils, as smooth rounds, from 5.5mm to 16mm diameter as well as 6mm to 12mm diameter hot/quenched rebar.

Source: Danieli, 17 August 2021

• China’s Inner Mongolia Region is about to embark upon a major power project designed to produce enough green hydrogen to displace around 180 million gallons of gasoline per year if it is used for fuel cell vehicles.

1.85 GW of solar and 370MW of wind power will be used to make just under 67kt of green hydrogen and work will commence in October, according to a report by the Hydrogen Energy Industry Promotion Association. Less than 20% of the power generated will go to the grid.

Source: Bloomberg, 18 August 2021

• US Steel has announced more blast furnace outages.

The company’s 2.54Mt/yr number 14 BF at its Gary Works in Indiana will start a 10-day stoppage beginning 30 November. The company also announced a seven-day outage starting 1 October for its 1.4Mt/yr BF-B at the St. Louis-area Granite City plant.

Source: SPGlobal, 18 August 2021

• Recognising that ferrous scrap is a valuable resource and an important raw material for steelmaking, Tata Steel India has commissioned a 500kt recycling plant in Rohtak, Haryana, the first of its kind in the country, it claims.

The company intends to set up a scrap supply chain in India and make its own steelmaking more sustainable.

Source: Economic Times, 18 August 2021

• Swedish steelmaker SSAB has manufactured the first fossil-free steel in the world and delivered it to a customer.

The test delivery, says SSAB, was an important milestone and a step towards a fully fossil-free iron and steel production value chain. It also represented a milestone for the HYBRIT partnership between the SSAB, LKAB and Vattenfall.

Source: SSAB, 18 August 2021

• EU28 apparent steel consumption increased (+3.6%) year-on-year in Q4 of 2020, the first quarterly growth since Q4 2019. It increased by 0.9% in Q1 2021, according to EUROFER, the European Steel Association. Apparent consumption in Q1 2021 amounted to 36.3Mt and, according to EUROFER, are further signs of recovery from the economic shock caused by COVID-19.

Source: EUROFER, 19 August 2021 • ThyssenKrupp AG of Germany is to sell its Carbon Components business to Action Composites GmbH as part of its restructuring plan.

The company makes highperformance braided wheels for cars, motorcycles and mountain bikes.

Source: Market Watch.com, 19 August 2021

• A planned merger between Anshan Iron & Steel and Benxi Iron & Steel has finally happened following the transfer of 51% of Benxi shares by Liaoning province to the state-owned Anshan Iron & Steel. Anshan – also known as Angang – will become the third largest steelmaker in the world once the deal is finalised, according to an online media report.

Source: SPGlobal.com, 20 August 2021

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NEWS ROUND-UP

• Indian steelmaker JSW Steel has set a target of 1.95 tonnes C02/tonne of steel by fiscal 2030, a reduction of 23% from fiscal 2020 and down 42% from 2005, the base year.

Source: Hellenic Shipping News.com, 21 August 2021

• The REDERS project is an initiative designed to strengthen the recycling cycle of iron and steel while reducing CO2 emissions. The partners involved in the project are thyssenkrupp Steel and Hüttenwerke Krupp Mannesmann, and Recycling GmbH and they are working under the scientific leadership of VDEhBetriebsforschungsinstitut GmbH. Source: ThyssenKrupp, 21 August 2021

• Thyssenkrupp Steel Europe (TKSE) has placed an order with the German plant builder SMS group for the supply of an annealing and insulating line for electric strip. The aim for TKSE is to renew core elements of its production network in order to meet future customer requirements. The focus of activities at the company’s Bochum site, where the new line will be installed, will be e-mobility. According to SMS group, from 2024, the new annealing and insulating line will turn out more than 200kt/yr of non-grain-oriented electric strip for electric motors and generators for EVs. Source: SMS group, 23 August 2021

• ThyssenKrupp Steel’s 5.4Mt/yr BOF meltshop 2 in Duisburg, Germany, is back in business after enforced downtime when the company relined its blast furnace 1. Hot metal from the blast furnace is mainly processed into crude steel in BOF meltshop 2, but the downtime incurred did not cause any additional production losses, claims tk.

Source: ThyssenKrupp, 24 August 2021

• Troubled UK steelmaker Liberty Steel is in talks with San Francisco, USA-based White Oak Global to discuss a possible refinancing deal that might bring to an end intermittent operation of the company’s UK operations.

Following the collapse of Greensill Capital earlier in the year, Liberty has been trying to keep its head above water amidst a criminal investigation and legal disputes with Greensill backers.

Source: The Guardian.com, 23 August 2021

• An environmentally friendly bulk carrier is to be developed

by Mitsui OSK Lines and Indian steelmaker Tata Steel. The aim, of course, is to reduce greenhouse gas emissions.

The two companies have signed a Memorandum of Understanding (MoU) with a view to exploring the environmental benefits and the commercial and operational feasibility of various technologies.

Source: Splash247.com, 24 August 2021

• Direct Reduced Iron (DRI) and ‘smart carbon’ will be used by steel giant ArcelorMittal to reduce its global carbon emissions intensity 25% by 2030. The steelmaker will spend around US$10 billion on the project and hopes to be net zero steelmaking by 2050.

Source: The Chemical Engineer, 25 August 2021

• In a move designed to simplify its ownership structure in Mexico, Brazilian steelmaker Gerdau has asked a regulatory agency in Mexico for permission to merge two of its businesses, Sidertúl and Aceros Corsa. The steelmaker’s board of directors have approved the merger.

Source: Recycling Today, 25 August 2021

• According to Fortune India, Tata Steel and JSW Steel will ‘lock horns’ over the purchase of Rashtriya Ispat Nigam Ltd (RINL), which is a state-owned steelmaking business currently up for sale as part of Narendra Modi’s disinvestment plan. ArcelorMittal Nippon Steel is also in the frame. Both Tata Steel and JSW have already been shortlisted as potential buyers of Neelachal Ispat Nigam Ltd (NINL) alongside ArcelorMittal. Source: Fortune India, 23 August 2021 www.steeltimesint.com

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NEWS ROUND-UP

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Steel Fact: In 2017, 35.5% of recycled steel (or steel scrap) is used in crude steel production globally, where 17.8% was used in China, 55.5% in Europe, 72.1% in the USA, 34.2% in Japan, 43% in the Republic of Korea, 80.8% in Turkey and 39.9% in Russia.

ArcelorMittal, has been optimizing its scrap recycling operations since 2015 with an average recycling rate of 85% of the steel produced.

Source: Bureau of International Recycling

• Clayton Equipment, the only British independent locomotive manufacturer in the UK capable of designing and manufacturing locomotives up to 150 tonnes, has agreed a contract to supply a further two hybrid+TM CBD90 locomotives to Tata Steel, Port Talbot, in the UK. The steelwork’s fleet will eventually include a total of seven Hybrid+TM locomotives supplied by the company.

Source: Clayton Equipment, 26 August 2021

• POSCO Energy, which is part of the POSCO steel group, has joined forces with Innowill, a domestic compact heat exchanger developer, to work on the development of technologies that can reduce carbon emissions using waste heat generation. In essence, ‘cogeneration’ refers to the use of waste heat from the manufacturing process to generate heat and useful heat.

Source: Korea Biz Wire, 30 August 2021

• Brazilian steelmaker Gerdau is to invest around US$14.45 million on environmental projects. The company will focus its attention on the Divinopolis facility in Mina Gerais state. The money to be invested represents over half of the mill’s total capital expenditure for 2021 (which totals US$25.05 million).

Source: Steel Orbis, 30 August 2021

• British Steel is to build a new £26 million downstream processing facility at its Skinningrove site in the UK. The project is part of a £100 million investment by the Chinese Jingye Group to improve British Steel’s manufacturing and environmental performance.

Source: British Steel, 26 August 2021

• Russian steelmaker PAO Severstal has completed its first delivery of large-diameter pipes to Greece. The pipes have a diameter of 1016mm and were produced at the Izhora Pipe Mill (ITZ), part of Severstal’s Russian Steel Division. The pipes were delivered by truck to Greece from the ITZ pipe mill in St. Petersburg.

Source: Severstal, 26 August 2021

• US steel giant Nucor Corporation’s electric arc furnace at its direct reduced iron (DRI) plant in Louisiana, USA, has survived unscathed after Hurricane Ida made landfall on 29 August. The site was closed just in case of problems, but will resume operations shortly, the company told Argus Media.

Source: Argus Media, 30 August 2021.

• Citing environment costs and social impacts, the planning regulator of New South Wales in Australia has turned down an application

by South Korean steelmaker POSCO to develop a coking coal mine and rail line. The Australian government has challenged the decision.

Source: Reuters, 31 August 2021

• Steel Authority of India Ltd (SAIL) is investing in the enhancement of its Gua mines. The stateowned steelmaker plans to install a 4Mt pallet plant in the Jharkhand mine and make other improvements over the next three years. Source: Livemint.com, 28 August 2021 www.steeltimesint.com

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NEWS ROUND-UP

• Majestic Steel in the USA has announced plans to add a steel processing and service centre to Nucor Corporation’s Blytheville campus in Arkansas. The new facility will occupy 515,000 square feet and create 225 jobs. The company plans to process steel bought from Nucor.

Source: Kait8.com, 31 August 2021

• Cherepovets Metallurgical Plant (CherMK) – a subsidiary of Russian steelmaker Severstal – has put its grinding ball rolling mill number three into commercial service. The mill is capable of producing grinding balls with a diameter of between 80100mm. Grinding balls of this type are in high demand for mining operations in Russia, Kazakhstan, Armenia and Tajikistan.

Source: Steel Orbis, 1 September 2021

• It is being reported that many steel mills in China will be suspending production for maintenance purposes.

Shaoguan Steel, Benxi Iron and Steel, Anshan Iron and Steel and other mills have announced plans to cease production. Output will be reduced short-term, but shutting down for maintenance will, it is claimed, improve the quality of steel production.

Source: Yieh Corp Steel News, 6 September 2021

• A report by TransitionZero, a climate analytics provider, says that steel production in China may be 88.01Mt for August 2021 and that the country’s crude steel production in 2021 could be 4-7% up. This, it is claimed, brings into question China’s ability to meet Governmentset targets limiting steel outputs to 2020 levels.

Source: TransitionZero, 7 September 2021

• USA-based Vested Metals of Florida has been named one of the fastest-growing privately-owned companies in America – for the third year in a row. The company is currently listed at 1,361 on the 2021 Inc 5000 list, the nation’s most prestigious ranking for independent businesses.

Source: Vested Metals, 3 September 2021

• Integrated stainless steel manufacturer Jindal Stainless (Hisar) has signed a Memorandum of Understanding with Malaviya National Institute of Technology, Jaipur (MNIT). The idea is to undertake research, new product development, solid waste management, and skill development. JSHL will provide industry expertise, raw material and infrastructure. MNIT will bring in its technical and educational know-how.

Source: Jindal Stainless (Hisar) Ltd, 7 September 2021

• ABB has signed a Memorandum of Understanding with Stäubli Electrical Connectors to collaborate in bringing solutions to market to reduce greenhouse gas emissions associated with heavy mining machinery. Stäubli is a leading manufacturer of connector solutions and ABB is a global technology company. Together they plan to explore the development of electrification solutions that will meet the demands of industrial applications.

Source: ABB, 3 September 2021 www.steeltimesint.com

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• ArcelorMittal will receive state funding from Germany for half of the amount it needs to invest in a direct reduced iron (DRI) steel plant that will use hydrogen produced with renewable electricity. According to a report by Reuters, Germany’s Environment Minister, Svenja Schultze, has said that the Government will pay 55 million Euros, subject to EU approval. The aim, according to ArcelorMittal, is to start producing so-called “green steel” from 2025.

Source: Reuters, 7 September 2021 September 2021

15/09/2021 11:42:27

Making our world more productive

Supporting decarbonization Through increased efficiency and use of Hydrogen

Linde supplies world-leading innovative and sustainable solutions that create long-lasting value and a route to zero carbon. For more than 100 years, Linde has supported the steel industry with gases and energy-efficient technologies.

Moreover, Linde successfully covers every part of the hydrogen value-chain, including its use to decarbonize steel production.

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17.05.21 11:49

Making our world more productive

Supporting decarbonization Through increased efficiency and use of Hydrogen

Linde supplies world-leading innovative and sustainable solutions that create long-lasting value and a route to zero carbon. For more than 100 years, Linde has supported the steel industry with gases and energy-efficient technologies.

Moreover, Linde successfully covers every part of the hydrogen value-chain, including its use to decarbonize steel production.

linde-gas.com/hydrogensteel

00429_Steel_International_Linde_REN_Sweden_gas_ad_A3_RZ.indd 1-2

17.05.21 11:49

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INNOVATIONS

PrecisionTractor for yard logistics KAMAG’s PrecisionTractor is claimed to be specially designed for yard logistics and was developed to ensure efficient and precise positioning of semi-trailers and container chassis.

While under development, the main focus was on safety, manoeuvrability and reliable use in the logistics yard.

The new KAMAG PT has an ergonomically optimized working space and has been specially designed for all handling tasks in a variety of settings including manufacturing.

KAMAG’s PrecisionTractor complements the company’s portfolio of yard logistics solutions and replaces the Wiesel truck. While the Wiesel truck, also known as the KAMAG PM, is number one among swap body handling vehicles, the KAMAG PT now presents itself as a specialist in moving and positioning semi-trailers and container chassis at depots and terminals.

KAMAG engineers have optimised manoeuvring processes and claims that coupling and uncoupling operations will be even faster in the future. A small turning radius and – thanks to an electronically co-ordinated, hydrostatic drive – continuous forward driving and reversing provide the KAMAG PT with precise and efficient driving characteristics, it is claimed.

The KAMAG PT impresses vehicle operators and drivers with its driving characteristics and driver-oriented ergonomics

In terms of driver safety, the driver’s cab now offers an even higher level of safety as enhanced visibility increases work safety and prevents collision damage, according to KAMAG. The cab has direct access to the work platform, which leads to significantly improved workflow, claims the company. Increased space behind the driver´s cab is claimed to make it easier to handle the supply lines.

KAMAG claims that vehicle operators benefit from the increased fifth-wheel load of 28 tonnes at 25 km/h and the hydraulically operated

height-adjustable fifth-wheel plate.

In addition to depot logistics, the heaviest chassis can be ‘easily and precisely’ moved in terminal logistics operations at seaports and airports, rail companies and industrial companies operating in the paper, steel or aluminium industries, which are known for their high load requirements.

For further information, log on to www.tii-group.com

Chinese steelmakers buy KOCKS RSBs Two Chinese steelmakers, Henan Jiyuan Iron & Steel and Jiangsu Yonggang Group Company Ltd, have both granted final acceptance certificates to Friedrich Kocks GmbH for 3-roll reducing and sizing blocks.

Henan Jiyuan Iron & Steel have taken delivery of a 300++/4 in 5.0 while Jiangsu Yonggang

Group Co – Kocks’ 100th customer – has opted for a 370++/4 in 5.0.

Since 2008 Henan Jiyuan has been operating a KOCKS RSB® 370++/4 in its bar mill number 1.

The new RSB® 300++/4 has been implemented in a relocated small bar mill where it replaces an existing 2-high sizing mill. The RSB® 5.0 is de-

signed for thermomechanical rolling and finishes seamless and most flexible all-straight bar sizes within a dimensional range from Ø 12.0mm to 42.0 mm onto the cooling bed.

Beside the reducing and sizing block (RSB) the roll shop preparation of the 3-roll stands and 3-roller guides were part of the scope of supply.

At Yonggang Group, the RSB 5.0 is at the heart of a new 700kt/yr SBQ rolling mill and enables the company to produce high-quality bars within a dimensional range of Ø 16.0 100.0 mm for customers in demanding industries such as machinery manufacturing, automotive, shipbuilding and wind power.

“We feel much honoured to be the 100th customer of the KOCKS 3-roll reducing and sizing Block” said Zheng Yuyang, plant director of Yonggang. “Jiangsu Yonggang Group decided to order a KOCKS 3-roll RSB because of its high reliability and comprehensive operation. KOCKS is the benchmark in the market due to its excellent technical reputation.”

With the investment in KOCKS 3-roll technology, Yonggang will play an outstanding role among the leading SBQ producers in tomorrow’s challenging world, claims KOCKS.

For further information, log on to www.kocks.de September 2021

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INNOVATIONS

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Bulk handling specialists join forces Combining 60 years of experience,specialist hydraulic manufacturer, Advanced Actuators and engineering designer, Ashton Bulk, have joined forces to offer a total-solution combining industry design expertise and established manufacturing skills. Operating together, the two companies have already fulfilled two multi-million pound contracts for major clients in the bulk handling industry. They now specialise in wagon tippling technology and offer a full consultation and design service, along with the manufacturing facilities, to create a turnkey service solution.

Mechanical, hydraulic and electrical design, intelligence and control systems can now be provided under one contract making customers’ projects much easier to manage, claims Advanced Actuators and Ashton Bulk.

“We have found from working together in the past that we offer complimentary services and work really well together. We’re aware of a gap

innovations.indd 2

in the market for a one-stop-shop where consultants can find experts to deliver their entire bulk handling projects from consultation, delivery and installation through to testing and commissioning. In short, we’re offering the brains and the muscle under one roof,” said Chris Woodhead, managing director of Advanced Actuators.

According to Woodhead, the two businesses are seeing a growing trend towards the use of tipplers over bottom dumpers in industries such as power, steel and ports, wherever unloading and stockyard equipment is used.

“It can be very costly to buy and maintain a fleet of bottom-dumping wagons,” said Woodhead, adding that tipplers tend to be more cost-effective and capable of handling trickier loads. “We’re now able to service that market from end-to-end,” he said.

Joe Dudman, projects director at Ashton Bulk, added: “We can provide all the expertise that

engineering consultants need in one place. By carefully selecting a supplier at specification stage, it’s possible to save significant amounts of money, simplify the process with less suppliers, and ensure longer lifespan of plant.”

Advanced Actuators has clients in the oil and gas, bulk handling, power, water and nuclear sectors and supplies standard and bespoke hydraulic engineering and servicing across the globe.

Ashton Bulk provides engineering design and project management solutions to bulk materials handling industries globally and has engineers with experience dating back 50 years.

The two companies first worked together in 2017 to deliver high-capacity train unloading systems for projects in South Africa and Guinea.

For further information, log on to www.advanced-actuators.com

15/09/2021 11:54:02

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INNOVATIONS

More upgrades for Konecranes lift trucks Konecranes has introduced four new ways of raising safety and productivity for its customers around the world.

All four upgrades are specific solutions that can be fitted to Konecranes lift trucks on customer sites. They are not service packages but are intended to improve equipment performance with the latest available technology.

“Safety and productivity are among the two most important priorities for our customers,” says Johan Kårhammer, global spare parts operations manager at Konecranes Lift Trucks. “So, in this latest release, they can choose any or all of two safety and two productivity packages that can be installed on one truck, all trucks at one site, or even across a global fleet.”

Of the two new safety improvements, an overhead guard is a retrofit for empty container handlers that will protect the operator from a falling object using a safety cage mounted around the cabin. Thankfully, falling objects are quite rare in container yards, but empty containers can sometimes drop accidentally due to the height of the mast. The retrofit is available only for Generation B and C empty container handlers.

Customers can also enhance lift truck safety by enhancing peripheral and forward visibility with a Roof LED Bar. This is a pre-assembled light fitting mounted on the truck’s roof to make operations brighter when the surrounding area is not fully illuminated, such as at night, in shadow, or indoors. Available at different illumination levels, it can be easily fitted to any type of forklift or container handler, and controlled from the operator’s dashboard inside the cabin. Better lighting reduces driver fatigue, as they are not distracted by the need to avoid hard-to-see obstacles and can fully focus on delivering the load safely.

Productivity can be boosted with a 2x105cc hydraulic pump upgrade. On Liftace reach stackers and TCE5 models with a suitable configuration,

replacing the existing 75cc pump with a 105cc model increases the operational speed of lifting, extending, retracting and manoeuvering actions.

Faster movements mean faster work cycles and the result is more container stacking during each shift. According to Konecranes, the pumps are easy to install and the difference in work flow is immediate.

A second productivity improvement is a static weighing system retrofit for Generation B and C reach stackers. Operators can weigh containers by lifting them for a few seconds, then touching a button to send the measured weight to a central database, such as the terminal operating system (TOS) or the yourKONECRANES customer portal, where it is linked to the container ID.

This provides the information for an automated verified gross mass (VGM) declaration with +/1% full-scale accuracy and eliminates the need for a separate weighing procedure when loading containers for transport. Reducing the time and processes required for each container to pass through the container yard, this retrofit saves on operational costs and increases overall site productivity, according to Konecranes.

Konecranes’ global distributor network will play a significant role in bringing the new Lifetime Advantage options to Konecranes customers around the world, it is claimed.

For further information, log on to www.konecranes.com

September 2021

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15/09/2021 11:54:10

INNOVATIONS

15

Steel plant saves big with spherical roller bearings For the past four years a hot rolling mill in Spain had been experiencing an unexpectedly short bearing life, leading to costly production stoppages. As a result, the plant worked closely with the technical department at leading bearing specialist NSK to assess the application and propose and implement a solution based on high-performance spherical roller bearings. By adopting NSK’s recommendations, the steel plant is now saving €69,803 per annum in reduced costs for downtime, maintenance, bearings and lubrication.

When performing a technical root cause failure analysis, NSK’s technical team analysed working conditions and the lubrication regime at the mill to optimise running conditions and prolong life.

Furthermore, in support of the maintenance department’s request for process improvement, NSK undertook a review of the bearing fitting process and tolerances.

Working in partnership with the steel plant, the information from the analyses and reviews indicated that the high running temperature of the bearings was emanating from a combination of incorrect fitting and lubrication failure due to higher productivity (running speed) at the plant.

Among the many recommendations was the

implementation of NSKHPS (High Performance Standard) spherical roller bearings with higher radial internal clearance to better suit the application conditions. NSK claims that its spherical roller bearings can withstand arduous operating conditions and resist seizure caused by constant vibration, misalignment and shock loads.

As a result of the new measures, bearing consumption at the mill has been reduced to one fifth of previous levels, with subsequent benefits in terms of less production downtime and maintenance.

NSKHPS spherical roller bearings are claimed to offer temperature stability up to 200°C, and a dynamic load rating 25% higher than the industry standard. The upshot is a bearing that provides twice the operating life of conventional alternatives, the company claims.

Aside from advanced motion technology, NSK offers extensive guidance on maximising bearing performance. In the case of the hot rolling mill application, the result was greater bearing life.

However, the company claims it can add value in many other ways, including the generation of higher productivity, the reduction of stock/inventory, enhanced customer skills through targeted

training, delivering on-site inspection and/or installation services, the provision of technical reports or lubrication analyses.

The Spanish mill was pleased with NSK’s recommendations and their subsequent benefits, as evidenced by a new order for NSKHPS spherical roller bearings when the market started to recover from the effects of the pandemic earlier this year.

For further information, log on to www.nsk.com

New and improved Spectro analyser SPECTRO Analytical Instruments has introduced the latest version of its SPECTROMAXx ARC/SPARK OES analyzer with next-generation improvements for the ultra-reliable advanced analysis of incoming and outgoing materials at metal producing and fabricating plants.

SPECTROMAXx instruments are a critical element of supply chains worldwide, claims Germany-based Spectro.

The SPECTROMAXx LMX09 analyzer offers ultrafast information to enable users to react rapidly to changing process conditions. It also provides a reduced cost of ownership with lower

consumables, plus advanced diagnostics and easy maintenance that increases availability and prevents expensive downtime, it is claimed.

Among the advantages offered by the new analyzer are significant reductions in argon gas consumption, an expanded wavelength range, fast and simple standardization using iCAL 2.0 to compensate for changes in environmental temperature or pressure, improved ease of use, and adaptor kits offering a variety of solutions to meet the wide range of analysis requirements of material control.

The SPECTROMAXx LMX09 ARC/ SPARK OES analyzer is available in two models, differing only in their optical systems. The basic model features SPECTRO’s proven single air optic with high-resolution CCD sensors. Its design

means it can resist fluctuations due to ambient temperature changes, and it handles elemental wavelengths from 233 nm to 670 nm. The SPECTROMAXx Advanced adds a new UV optic with four high-resolution CMOS detectors and its extended wavelength range covers elements from 120 nm to 235 nm.

All SPECTROMAXx analyzers are supported by AMECARE through machine-to-machine support, providing proactive alerts and an on-request PC connection with a remote SPECTRO service expert.

The SPECTROMAXx LMX09 ARC/SPARK OES analyzer is available from SPECTRO Analytical Instruments.

For further information, log on to www.spectro.com/mazz

September 2021

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15/09/2021 11:54:16

16

INNOVATIONS

Combilift has delivered the largest multi-directional forklift to come off its production lines.

The giant 30t capacity C30,000 truck is now in operation at BladeRoom’s factory in Gloucestershire, where it is ensuring the efficient handling of components for the company’s server rooms, as well as finished products, which are comparable in size to shipping containers and can weigh up to 19 tonnes.

BladeRoom, a modular data centre manufacturer, ordered a 25t C25,000 model in 2010, which was at the time the largest C-Series that Combilift had built. It is still in operation at the Mitcheldean factory, along with a number of other Combilifts of varying load capacities, which handle raw materials such as RSJs and roof structures.

BladeRoom’s data centres incorporate computer fluid dynamics to extract the maximum amount of heat with the minimum use of mechanical cooling for a highly efficient cooling

Largest ever Combilift C-Series forklift delivered

system. These pre-engineered, factory built, energy efficient data centres are fully fitted out for immediate use and supplied within a much shorter time frame than that for traditional structures. This minimises customers’ capital outlay and offers the lowest possible operational costs, says Combilift.

“The initial challenge for BladeRoom was how to easily, quickly and safely manoeuvre these extremely large loads in and around the site,” said Rob Perry of HFT Forklifts Ltd (Hereford), BladeRoom’s MHE consultants and Combilift’s dealership in the area. “Fixed cranes would have been too inflexible, and the sheer physical size of a counterbalance forklift capable of moving these structures would have taken up far too much space in the manufacturing area. Following the successful operation of the C25,000 over the years and the growing size and weight of the data centres, BladeRoom decided to scale up its newest Combilift.”

The C30,000 measures around 5m x 5m, has a wheel base of 3,725mm and is fitted with a John Deere Diesel 127 kW (170HP) engine, and also incorporates customised features which enable the safe and stable lifting and transportation of BladeRoom’s oversized loads. These include four cameras (one of which is a reversing camera), with two camera monitors in the cab, red danger zone lights and a tilt indicator in the cab display.

“It’s a very impressive piece of machinery”, said Rob, “and in spite of its size, its four-way ability enables it to move easily around the manufacturing facility. We are very proud of the fact that HFT was instrumental in supplying the largest Combilift C-Series model, not just in the UK, but worldwide.”

For further information, log on to www.combilift.com

Measuring system for handheld X-ray guns Henkel Adhesive Technologies has developed a measuring system for mobile handheld XRF spectrometers or X-ray guns.

The measuring system was tested at Claas Bad Saulgau and was used on the agricultural machinery parts manufacturer’s production line to investigate the potential of replacing the powder activation Bonderite M-AC 50-1 with the liquid activation Bonderite MAC AL 2000. Rather than requiring laboratory analysis, the new system was able to measure the coating weight (CW) of the Zn phosphate (ZnPO4) layer through the e-coat on the steel substrate in approximately 10 seconds. Using the X-ray gun, it was possible to directly and accurately analyze the activation parameters, thereby enabling Henkel Adhesive Technologies to optimize these parameters in just one day. The measured part is called “Mulde” and is made from cold rolled steel with 4g/mÇ Zn-PO4 layer and an e-coat. For Claas this meant there was no need to slow down or interrupt full production during tests – nor risk any loss of quality, for example in corrosion protection.

The new solution, which combined the X-ray gun and the special measuring system from Henkel and Analyticon instruments provided a way to achieve analysis on the production line – rather September 2021

innovations.indd 5

than in a laboratory, which would have taken several days or weeks. Thus, Henkel’s technical expertise combined with Analyticon’s equipment has resulted in a highly efficient process that saved Claas Bad Saulgau time and money, while also using fewer resources over the long term.

“At Henkel, process efficiency and sustainability are core concerns that we consider in everything we do”, said Andy Bender, chemical engineer at Henkel Adhesive Technologies. “We are also committed to working with our partners to develop the best possible solutions for our customers.

Thanks to the new measuring system for the X-ray gun, we are able to save our customer Claas

Bad Saulgau an immense amount of time, optimizing processes at an unprecedented speed.”

The X-ray fluorescence analysis, or XRF, is a fast, non-destructive method for analyzing the chemical element composition of a sample accurately. It can be used to determine the type and quantity of measurable elements. The concentrations of the elements are analyzed independently of their chemical bonding – this works across the wide spectrum from magnesium (Mg) to uranium (U). The Niton XL-2 XRF gun is claimed to measure the exact composition of metal alloys in seconds – reliably and without significant sample preparation, according to Henkel. It can identify stainless steels, non-ferrous metals and, based on their silicon and magnesium content, aluminium alloys too. The X-ray gun is claimed to offer significant advantages both in quality assurance and mix-up testing as well as in the field of metal recycling, which can be enormously simplified using the X-ray gun.

Users of the X-ray gun require dedicated training, such as that provided by Henkel’s technical experts. It must not be used without training.

For further information, log on to www.henkel.com www.steeltimesint.com

15/09/2021 11:54:24

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USA UPDATE

19

Imports and production not yet at pre-pandemic levels

US industry experts say that business sentiment within the US steel sector can be gauged by the level of steel imported into the country as well as by the domestic steel produced. By Manik Mehta* STEEL imports into the US during the first half of 2021 surged over the previous year’s corresponding period; however, imports were lower when compared to the same period of 2019 when the COVID-19 pandemic had not impacted the steel sector.

During the first half of this year, steel imports surged to 13.37Mt, up 19% over the 11.28Mt during the corresponding period in 2020, as data from the US Department of Commerce shows. The 2021 imports were 6% below the 14.17Mt imported during the first half of 2019 prior to the pandemic’s outbreak.

Steel production is also showing signs of an upward surge. According to the American Iron and Steel Institute (AISI), the industry association, raw steel production had totaled 46.9Mt until 3 July, posting a 16% rise over the previous year’s corresponding period. However, the total figure also translates as a 6.5% drop compared to the production in the same period of 2019.

However, some experts say that the lower import and production levels compared to pre-pandemic levels, coupled by claims from many steel buyers that they are

working at or above pre-pandemic levels, can lead to steel shortages, thus giving a fillip to rising prices.

The steel industry is pinning its hopes on offshore turbines to provide the big boost it needs. A proposed wind turbine manufacturing hub in Baltimore, according to steel workers, appears to have raised hopes of the steel industry as well as workers, although the latter were initially skeptical about President Joe Biden’s portrayal of the climate crisis as the greatest opportunity to create jobs.

US Wind, a developer of offshore wind farms, announced that it was planning to expand its in-development 22-turbine project off the coast of Maryland, and add up to 82 more turbines that will make the facility capable of powering half-a-million homes. US Wind has also proposed constructing a new wind turbine manufacturing facility just outside Baltimore.

The plant, called Sparrows Point Steel, will fabricate monopiles, the steel foundations that anchor giant wind turbines to the seafloor. It will sit on the site of the former Bethlehem Steel Corp. mill and shipyard, which produced steel for

ships used in World War II and also for San Francisco’s Golden Gate bridge.

The new wind farm off the coast of Maryland alone is estimated to create 3,500 construction jobs and 100 operations jobs, according to US Wind. However, the company maintains that the steel plant could create an additional 500 permanent – and well-paid – jobs on reaching full capacity. US Wind has already entered into a memorandum of understanding with the United Steelworkers union, local branches of the International Brotherhood of Electrical Workers, and the Baltimore-DC Building Trades Council.

The prospect of steel workers getting high-paying jobs in welding, operating machinery, fabrication and crane operations is a strong attraction. It would be cheaper to build the monopiles in Maryland because this would eliminate the high shipping costs on imports from Europe, as Nancy Sopko, director of external affairs at US Wind, recently explained.

Other states are also eyeing the wind turbine business. New Jersey’s governor Phil Murphy, for instance, is courting wind turbine component manufacturers for a second port being developed on an

* USA correspondent www.steeltimesint.com

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USA UPDATE

artificial island in southern New Jersey, while New York is investing in a wind turbine manufacturing site at the Port of Albany. Studies made by Princeton University researchers suggest that domestic manufacturing currently accounts for roughly 79% of the supply chain for landbased wind projects in the US. Indeed, the Maryland, New Jersey and New York facilities would be the first in the country to build offshore components. The three states have been particularly ‘encouraged’ by President Biden’s infrastructure bill, which places emphasis on energy manufacturing facilities and reducing emissions at industrial plants.

Amid the rise in steel prices this year, the chief executive of Pittsburgh-based US Steel Corp. said his company does not plan to increase production. David Burritt, told analysts during a conference call on the company’s second quarter earnings that he is, instead, striving to add capabilities for higher-value products.

Burritt cautioned the analysts not to look “for us to add a bunch of capacity … look for us to add capability for profitable growth”.

For the second quarter ending 30 June, US Steel reported adjusted net earnings of $964 million, compared to a net loss of $469 million during the same period a year go.

The company recorded net sales of $5.03 billion in the second quarter ending 30 June, compared to $2.9 billion a year ago.

“The second quarter was an exceptional quarter for US Steel,” Burritt said.

This is a unique time for US steelmakers who are witnessing robust earnings before taxes and depreciation. Analysts predict strong earnings again in US Steel’s third September 2021

USA.indd 2

quarter.

Burritt highlighted the fact that his company’s long-term strategy would focus on sustainable and high-tech production, including at the company’s Big River Steel mini mill in Arkansas.

“We recently announced an investment

in a state-of-the-art non-grain oriented electrical steel line that will further Big River Steel’s industry-leading position. This investment allows us to partner with auto OEMs (original equipment manufacturers) on their own decarbonization goals,” he said.

US car manufacturers and the steel industry have welcomed President Biden’s 5 August executive order aimed at having zero emissions in half of all domestic vehicle sales by 2030 and develop long-term efficiency and emissions standards. Biden had signed the executive order during a White House event attended by automobile executives and trade unionists.

US car manufacturers have endorsed the administration’s push toward electrification, with the nation’s ‘big three’ – Ford, General

Motors and Stellantis – voluntarily pledging to achieve sales of 40% to 50% of annual US volumes of electric vehicles (EVs) by 2030.

“Our recent product, technology, and investment announcements highlight our collective commitment to be leaders in the US transition to electric vehicles,” Ford, GM and Stellantis said in a joint statement.

The current bipartisan infrastructure bill introduced in the Senate includes a $7.5 billion investment to build a national network of electric vehicle chargers, the first-ever national investment in EV charging infrastructure, but lower than Biden’s initial proposal of $15 billion.

In a fact sheet, the White House said this action on EVs is being taken as the US has fallen behind other countries in the race to manufacture both electric vehicles and batteries.

The current US market share of EVs is one-third that of China’s market, according to the White House.

There are currently only about two million EVs on US roads today, and only 2% of cars sold in 2020 were fully electric, according to data from the International Energy Agency.

The United Autoworkers union, (UAW) which said it supports the executive order actions, called for clarity about emissions standards which will bring more certainty and better planning for the industry and future employment.

The AISI has also welcomed the new EV and emission goals by providing, as its CEO Kevin Dempsey said, ‘innovative, high-strength steels that combine lighter weight and increased strength. Importantly, these thinner advanced grades of steel enable optimization of space allowing for packaging of more batteries in these vehicles, which means greater range on a single charge’.

The AISI has also applauded the passage of the infrastructure bill in the Senate.

Dempsey said: “We applaud the Senate for advancing this bipartisan legislation that will spur economic growth and job creation throughout the country. Passage of this bill … gets us one step closer to making long overdue investments in our nation’s roads, bridges, transit systems and other essential infrastructure using American-made steel.

We look forward to working with the House of Representatives to get this bill to the President’s desk as soon as possible.” � www.steeltimesint.com

15/09/2021 11:45:30

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2021-07-30 10:11 AM

23

LATIN AMERICA UPDATE

Chilean steel is doing well Chile is undertstood to have experienced, after its redemocratisation in 1990, one of the most stable macroeconomic and political conditions in Latin America. By Germano Mendes de Paula* IT is worth noting that Chile is an investment grade country according to S&P, Moody’s and Fitch. In addition, Chile and Uruguay have the largest degree of COVID-19 vaccination in the region.

On 28 July 2021, 72.9% of the Chilean population had taken one dose and 64.2% was fully vaccinated. Meanwhile, the global respective data were 27.8% and 14.2%.

However, the nation has been shaken by violent protests since 2019 and it is engaged in a Constitutional rewriting and new mining royalty legislation. Bearing these institutional risks in mind, this article pays attention to the Chilean steel industry’s situation.

The Chilean economy Chile has 19 million inhabitants, of which 6.8 million live in its capital Santiago. The pandemic has increased poverty levels in the country, interrupting a tendency towards declining poverty observed since 1990. According to data from the National Socioeconomic Characterisation Survey (Casen), released in July 2021, COVID-19 raised poverty levels from 8.6% in 2017 to

10.8% in 2021. This means that it has 2.1 million poor inhabitants, of which 831,000 are in extreme poverty.

The extractive industries, which include mining and oil & gas, is a crucial economic activity in Chile. The UN Economic Commission for Latin America and the Caribbean (ECLAC) estimated that extractive industries were equivalent to some 10% of Chile’s GDP in 2019. For the sake of comparison, the figure was roughly 11% in Bolivia, 9% in Peru, 4% in Argentina and Mexico and only 3% in Brazil.

Indeed, according to S&P Global Market Intelligence, Chile accounts for 24.8% of the estimated global copper production

this year and for 19.2% of world lithium production.

Table 1 shows some key Chilean macroeconomic indicators, extracted from a report published by S&P in late June 2021. GDP diminished by 6.0% in 2020 and it is expected to recover by 6.9% this year, followed by approximately 3.0% enlargement per annum in the period 2022-2024. Inflation has been quite well behaved, as the consumer price index (CPI) rose by 3.0% in 2019-2020 and it is expected to surge by 3.7% in 2021 and then decrease gradually until it reaches 3.0% as of 2024. The interest rates are relatively low by Latin American standards.

Table 1. Chile’s macroeconomic indicators, 2019-2024. Source: S&P

* Professor in Economics, Federal University of Uberlândia, Brazil. E-mail: germano@ufu.br www.steeltimesint.com

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LATIN AMERICA UPDATE

The Central Bank’s policy interest rate was 0.5% at the end of 2020 and it is estimated that it will be 1.0% as of December this year, increasing slowly until it reaches 3.0% in late 2024. The nominal exchange rate has been quite stable, as the Chilean Peso (CLP) was 745 to the dollar at end of 2019 and it is expected to come back to the same level in late 2023.

New constitution and mining royalties In May 2020, the Chileans went to the polls for a pivotal vote to select 155 delegates for a new Constitutional Convention that will be tasked with writing a new constitution: 138 of the delegates were chosen directly by voters, while 17 were reserved for indigenous peoples. According to Goldman Sachs: “The new Constitutional Convention will be highly fragmented. Independent and far-left candidates performed significantly better than expected at the expense of centre-right and traditional centre-left candidates/parties (…) we expect the new Constitution to validation of a larger, more interventionist state and the broadening of the social safety net to meet social demands for better public healthcare and education services, higher pensions, and lower inequality”.

The Chilean lower chamber of Congress in May 2021 voted in favour of a royalty bill that would impose a flat 3% on sales of both copper and lithium and add a mechanism of marginal rates as copper prices rise, with the highest bracket set at 75%. Currently, the bill is under discussion in the Senate, where the big mining companies hope that it might change towards being more market-friendly legislation. Therefore, in addition to COVID-19, the Chilean institutional environment has been stunned by Constitutional reform and new mining royalty legislation. It should also be remembered that round one of the presidential election is scheduled for 21 November 2021.

The steel industry’s linkages and performance Before examining Chile’s steel business performance, it is worth paying some attention to its economic linkages.

According to the Chilean Steel Institute (ICHA), the sector directly generated 1,422 jobs in 2019. Nonetheless, considering the backward linkages, it fostered another September 2021

LA Update.indd 2

Table 2. Chile’s steel market, 2016-2021 (kt). Source: Alacero, Chilean Steel Institute (ICHA) and own estimation for 2021

15,960 jobs, distributed among scrap processors (13,750), iron ore mining (2,310) and other suppliers (1,500). In terms of the forward linkage, the steel industry impacted 52,500 jobs in the manufacturing industry and 5,800 others in steel product distribution.

Table 2 shows Chilean steel industry activities in recent years and an estimation for 2021 (based on the annualised figures for January-April). Compañía Siderúrgica Huachipato (CSH, a subsidiary of Compañía de Acero del Pacífico or CAP Acero), the only pig iron producer in the country, has maintained its output around a plateau of 650kt/yr between 2016-2020 and it is expected to achieve approximately 700kt this year.

Chile has two steel producers: CSH and AZA (a minimill plant, which belonged to Gerdau until 2018). Both companies fabricated only long steel products, as CSH interrupted its flat steel operation in 2013. The national crude steel average in the 2016-2020 period was equivalent to 1.15Mt, being not materially impacted by COVID-19. Furthermore, for this year, 2021, output is planned to reach 1.3Mt. Where rolled steel production is concerned, the respective figures are 1.11Mt and 1.23Mt, which is similar to the recent maximum observed in 2018. It should be stressed that rolled steel fabrication was only 4% lower in 2020 than 2019, showing that the Chilean industry was able to sustain its volumes despite the pandemic.

Table 2 demonstrates that rolled steel imports diminished from 1.9Mt in 2019 to 1.5Mt in 2020, while exports witnessed a

retraction from 234kt to 202kt, respectively.

More importantly, apparent rolled steel consumption plummeted from 2.8Mt in 2019 to 2.4Mt in 2020, implying a significant 16% drop (in contrast to a 33.6% retraction in 2009, due to the global financial crisis). However, apparent demand will achieve 3.3 Mt in 2021 (based on annualised figures), which would be equivalent to a 17% jump in comparison with 2019. It is necessary to highlight that, in March 2021, ICHA announced that apparent steel consumption would reach 2.5-2.6Mt this year (an increase of between 6.5% and 9.5%, mainly explained by the construction and mining sectors’ good performance, besides the low comparison base of 2020). As a consequence, the steel business situation has improved since then.

ICHA also stressed that there are other variables of high impact for the future of apparent steel consumption in Chile, such as the measurement of the industry’s carbon footprint (and the application of taxes), the circular economy and waste control in the construction industry.

As can be verified in Table 2, the apparent demand of longs declined 12.2% in 2020 y-o-y, while flats registered a contraction of 17.5% and seamless tubes 67.1%. For 2021, it is expected that flats consumption will be 28.8% higher than 2019, whereas for longs it will be 17% bigger and for seamless tubes it will be 57.4% lower (but a similar level to that of the 2016-2018 period).

Despite COVID-19 and new institutional risks, so far, the Chilean steel market is in a favourable situation this year.� www.steeltimesint.com

15/09/2021 11:44:30

26

INDIA UPDATE

Infrastructure drives steel recovery After a steep decline in the financial year 2020-21 (April to March) on account of Covid-19-induced lockdown, India’s steel consumption has rebounded since June 2021 due to the government’s increased focus on infrastructure development and sporadic private investment on stalled as well as new projects. By Dilip Jha* ACTIVITIES around the infrastructure and construction sectors, which cumulatively contribute nearly two thirds of India’s steel consumption, had come to a grinding halt since the pandemic outbreak was first reported in February 2020 in India.

Construction work has restarted on stalled projects with a gradual opening up of the economy following a fall in the number of new Covid cases. New infrastructure and construction projects are also coming on stream, which is boosting existing steel demand in India.

Data compiled by the Ministry of Steel show India’s crude and finished steel

production at 102.49Mt and 94.66Mt for the financial year 2020-21 (April - March), a decline of 6.1% and 7.8% respectively from the previous financial year of 2019-20 (April - March). India’s finished steel consumption is reported to have declined by 6.7% at 93.43Mt for the financial year 2020-21 (April - March). The Ministry has attributed the Covid pandemic-induced lockdown to the decline in production and consumption of steel in India.

Recovery after initial pause After a painful first half of the financial year 2020-21 (April - March), the steel

sector recovered from the initial wave of the pandemic and returned with a much better performance in the second half.

However, the second wave of Covid-19 and concomitant localised lockdowns again adversely affected production and consumption of steel during the initial two months (April and May 2021) but not to the same extent as in the first phase.

Steel production and consumption have, however, been steadily improving since May 2021. Between June and July both production and consumption have shot up sharply with major producers witnessing the best ever months for the growth in steel

BOOMING PHASE – Sectorwise steel consumption End-use industry

Product type

Share

Construction

Commodity items like rebar, hi-beams, pipes and coated sheets.

62

Capital goods

Prospects

in demand (%) Strong: Logistics infrastructure (highway construction, industrial corridors, freight corridors, affordable housing and power transmission).

Steel plates, sheets, pipes, bars and specialty and highly functional steel.

15

Strong: Dependent on economic growth and secondary sectors such as construction, heavy and light industries and government spending.

Automobiles

Surface treated sheets, advanced high strength, galvanized and coated steels,

9

specialty steels with high tenacity, mechanical strength and wear resistance,

steel plates, sheets, pipes and bars

Weak: Short-term issues around regulations, affordability, financing, industrial activity and Covid-induced lockdowns.

.

Intermediate products

Gearboxes, bearings, pipes, drums and barrels.

6

Moderate: Closely linked to the auto; oil and gas sectors, packaging (drums and barrels).

Consumer durables Sheets, strips, plates and stainless steel.

5

Strong: Linked to GDP and consumer spending power.

Railways

3

Strong: Large planned investments on track electrification, dedicated freight

Sheet metals, special property steel, such as corrosion-resistant for tracks.

corridors and high-speed rail.

Source: Steel industry

* India correspondent September 2021

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15/09/2021 11:43:33

INDIA UPDATE

consumption in the last 10-15 years.

A senior executive with ArcelorMittal Nippon Steel India commented, “Domestic steel demand showed signs of revival towards the end of the June quarter, particularly from the automotive, white goods and infrastructure sectors. The higher local demand is likely to impact India’s steel exports, which jumped to 17Mt last year.

Shipments will fall slightly below that level this year as steelmakers divert more supply to meet local demand. JSW Steel, which reported its best quarterly profit in the three months through June, said higher volumes and growing local demand are helping the company offset rising input prices.

“Spending on infrastructure and decarbonisation across the world is keeping steel demand and prices at an elevated level in the US, Europe and China despite the supply uptick. Unlike the last commodity boom, which was led by oil and gold, this time metals – including steel – are leading the charge,” said Seshagiri Rao, joint managing director and chief financial officer, JSW Steel. The company (JSW Steel) reported its highest profit at INR 59 billion

India.indd 2

and revenue at INR 289.02 billion in the April - June quarter that was marred by the brutal second wave of Covid-19. With this elevated demand, India’s steel consumption is estimated at 110Mt for the financial year 2021-22 (April - March) compared with 94Mt reported in the last fiscal.

Tata Steel managing director and chief executive officer T V Narendran, said in an interview that the steel industry was currently in a much better place than it had been over the past 10 to 15 years because of the positive demand side and lower supply from China. Thus, the oversupply situation that was plaguing the industry until a few months ago is less of an issue now. Tata Steel expects India’s steel demand cycle to stay strong for a sustained period as the global economy is recovering from the pandemic.

Rating agency Icra said in its latest report that the sagging fortunes of long steel product manufacturers were set to revive strongly in the coming quarters, following years of anaemic growth, driven by increased construction activity. In particular, medium and small long steel product

27

manufacturers (players taking the sponge iron - electric arc furnace (EAF) / induction furnace (IF) route) who unlike their larger peers (players using the blast furnace basic oxygen furnace (BF- BoF) route), have suffered more during recent years and will now benefit from this strong demand uptick.

Outlook Meanwhile, the demand uptick stemming from the government’s thrust on infrastructure, particularly in rural markets, apart from the pick-up in local small ticket construction activity, is set to lead to increased steel off-take in the coming quarters. Major steel demand is seen coming in from segments like yellow goods, appliances, solar, packaging and residential construction.

With this, the July-September 2021 quarter, though sluggish, will be better than the April-June quarter, when steel consumption in India was reported at 24.7Mt compared with 30Mt in the January-March 2021 quarter, (and a mere 12Mt in the April-June 2020 quarter). �

15/09/2021 11:43:34

28

IRON ORE

Marampa’s best-quality African ore Sierra Leone’s capital Freetown has witnessed the first export of over-65% iron content from ore

by Marampa Mines Limited (MML). The shipment, which is bound for Chinese steel mills, follows the resolution of a long-standing dispute between SL Mining/Gerald Group and the Sierra Leone Government. The latter has been resolved out-of-court and described as win-win by both parties.

By Michael Schwartz* MML is a strategic asset of Gerald Group, the Anglo-American metals trading house founded in 1962, and the world’s oldest and largest independent, employee-owned global metals merchant. Marampa was previously under care and maintenance, with around 700kt of MML’s Marampa BlueTM product stockpiled. As this stockpile is depleted over the next few months to make room for new production, MML is reactivating equipment, mobilising contractors, effecting repairs, and bringing people back to work; 1,400 jobs are expected to be created this year of which the target is at least a 90% Sierra Leonean workforce. Recommissioning is set for December 2021.

The first ocean-going vessel (OGV) arrived in early July and left Sierra Leone

with 61.4kt of Marampa Blue iron ore.

The material was loaded by coasters at the company’s own (private) port, Thofeyim River Terminal on the Port Loko river, and carried to the port of Freetown, where loading of around 60kt of iron ore onto the next OGV has started. The destination is China’s steel mills. China is the largest consumer of iron ore in the world.

MML takes its name from the two Marampa resources in Sierra Leone: Marampa South, which offers 1 billion tonnes of iron ore and Marampa North, which offers another 700Mt. The increased area is earmarked by MML for further exploration. Following the signing of a binding MoU between the Government of Sierra Leone and Gerald Group, a new company, Marampa Mines Limited, was

formed where Gerald owns 90% of MML and the Government owns the remaining 10%; 2.0-3.25 Mt/yr of ore is the nearterm target and Gerald has committed to materially expand production at Marampa.

MML is particularly proud of the quality of its iron ore, which is one of the highest quality grades exported out of Africa. As Shan Radstone, Gerald’s head of iron ore, stated to STI regarding quality, “We are currently exporting concentrate with iron content above 65%, which we believe to be among the highest quality grade on the Continent.”

Why is the ore called Marampa Blue?

MML has chosen the term Marampa Blue as a reference to product quality and also to mark a clear departure from what had been

* Iron ore correspondent September 2021

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16/09/2021 12:20:59

IRON ORE

29

Safety Storage Efficiency

previously produced, namely an iron content well below 65% and with high impurities. Radstone continues: “Branding the product Marampa Blue reflects the physical characteristics of the ore and clearly differentiates this new high-grade material under MML’s operations from the lower grade materials produced by previous operators. This focus on quality is a core principle of our strategic approach to the evolving market demand.”

Through its connections as part of the Gerald Group, MML will have access to experienced teams in China and Europe.

These latter will provide support for defining and implementing a marketing strategy to achieve the best possible outcome.

Consequently, MML will incorporate feedback from the market in order to change plant parameters and to optimise product specifications. It is MML’s plan that Marampa Blue will have buyers in China and Europe.

www.steeltimesint.com

iron ore.indd 2

p

Are there CSR obligations?

MML informed STI that community obligations are always an important element of any mining project and the company states that its, “initiatives are aimed at embracing the challenges relating to climate change, gender diversity, sustainable farming and education through development of sustainable projects that make a difference to communities. Apart from direct initiatives, the company will also contribute to a community development fund, which will become more important over the life of the project as production increases.”

Past corporate social responsibility (CSR) initiatives by Gerald in 2018-2019 include distributing 100 tonnes of rice to outlying communities in the major Lunsar township, materials for school children, contributions to religious festivals, training local men and women to start their own businesses, and building 14 wells in the townships around the mine.

MML’s project is the largest in Sierra Leone, and is in addition making a substantial socio-economic impact in areas brutally hit both by the previous near-collapse of the mining sector and by the Ebola epidemic. �

Manage your steel more safely and more productively using less space with Combilift’s materials handling solutions

combilift.com 16/09/2021 12:21:01

30

SPECIAL STEELS

‘Hydrogen economy’ is a mantra of our times, making environmentalists dream of a carbon-free future and enthusing investors placing their financial bets. Prerequisites for a large-scale use of hydrogen in the intended range of applications, including energy delivery, steel making, chemical processing and transportation, are its efficient generation, preferably using renewable energy sources, as well as its safe transportation and storage.

Without any doubt, much of the necessary infrastructure will have to be made from steel. Yet, the contact of hydrogen with metals, and in particular high-strength steels, can cause unfavorable effects on the material performance under specific circumstances. More precisely, the coincidence of atomic hydrogen absorbed by the steel, high yield strength and a localized three-dimensional stress state promotes premature failure of a component even when loaded below design stress. What makes matters worse is that failure often does not occur imminently with the application of a load, but only after some time. So-called delayed cracking has been observed appearing even days after manufacturing (Fig 1) or taking components into service, and is thus a serious concern regarding quality monitoring.

Hydrogen embrittlement (HE) is caused by residual hydrogen accumulated within the bulk of the steel during prior processing, such as steel making, galvanic treatments or welding. Alternatively, embrittlement might result from the exposure of steel to a hydrogen-containing or corrosive environment during service. Procedures have been developed to reduce hydrogen uptake into the steel during processing or to remove it before applying any service loads. The potential in-situ hydrogen uptake during service life requires protective measures, for instance by passive or active corrosion control. In either case avoiding hydrogen absorption into steel is a tedious and costly exercise. On the other hand, various efforts have been taken to develop high-strength steels with an intrinsically better resistance against hydrogen embrittlement. This approach builds on optimizing microstructures and involving superior alloying concepts.

To be successful in that respect, one needs to understand the mechanisms that

Delayed cracking – a serious challenge for ultra-high strength steel Strong steels are sensitive to hydrogen-induced failure.

Molybdenum alloying can ease the pain.

By Professor Hardy Mohrbacher*

generate hydrogen-induced material failure.

Hydrogen gas is made up from bi-atomic H2 molecules. However, hydrogen dissolves in steel only as a single atom. Therefore, a process of dissociating H2 molecules at the steel surface is needed. Since the hydrogen atom has the smallest size of all chemical elements, it can travel very easily through the steel lattice by the process of diffusion.

The classical interpretation of hydrogeninduced damage is that single hydrogen atoms diffuse to voids or cavities inside the material and recombine there to bi-atomic molecules, thereby gradually building up an internal pressure triggering damage such as the formation of blisters or internal cracks

(Fig 2). This mechanism, which is rather relevant to lower strength steels, does indeed occur, especially in situations where an abundant hydrogen supply prevails.

On the contrary, just the presence of an extremely small amount of hydrogen can cause damage in ultra-high strength steel.

The critical level of hydrogen decreases with the increasing strength of the steel.

The threshold may even be below one part per million (weight ppm) of contained hydrogen for steels in the 1,500 to 2,000 MPa strength range. The small quantity of hydrogen is rather homogeneously distributed in the steel matrix in the absence of stress. Yet, after applying a load,

* NiobelCon BV September 2021

Special steel IMOA.indd 1

www.steeltimesint.com

15/09/2021 11:57:40

SPECIAL STEELS

Ultra-high strength steel bolts under constant stress and exposed to environmental corrosion Photo credit: Alamy

hydrogen is attracted to areas where a three-dimensional state of tension stresses prevails. This three-dimensional stress state is likely induced by geometrical notches and at microstructural inhomogeneities, such as hard inclusions or pre-existing crack tips. The locally widened iron lattice in the stressed area is an energetically favourable site for accommodating hydrogen atoms. Other attractive sites for hydrogen aggregation are zones with disordered lattice structure such as grain and phase boundaries. The locally elevated concentration of hydrogen has the effect of weakening the bonding strength between the iron atoms or reducing the cohesion of boundaries. Thus, a relatively low stress level is sufficient to separate the material, www.steeltimesint.com

Special steel IMOA.indd 2

producing a crack. This damage mechanism is known as hydrogen-enhanced decohesion (HEDE). Recent investigations have indicated that in martensitic press hardening steel hydrogen-induced boundary decohesion can occur at stresses as low as 400 MPa, while the nominal yield strength of the steel is more than 1000 MPa. Consequently, the crack propagates along the grain boundary in an entirely brittle fashion generating the facetted fracture surface characteristic of so-called intergranular fracture (Fig 3a).

While the appearance of intergranular fracture indicates the action of hydrogen embrittlement, other damage mechanisms caused by hydrogen are more difficult to recognize. Hydrogen-enhanced local plasticity (HELP) increases the mobility

31

of dislocations, especially in the vicinity of stress-raising discontinuities such as notches, crack tips or inclusions. The action of the HELP mechanism is often associated with so-called quasi-cleavage fracture (Fig 3b) combining mostly brittle appearance with some remnant plastic deformation. Increased dislocation activity promoted by HELP, on the other hand, generates increased amounts of vacancies, which are point defects in the iron lattice – think of an empty lattice position. The mechanism called hydrogen-enhanced strain induced vacancy formation (HESIV) energetically facilitates the formation of such point defects and stabilizes them.

These vacancies can condensate into twodimensional defects (Fig 3c), which in turn may coalesce and form voids. The resulting dimple-type damage appearance resembles that of a ductile fracture. HELP and HESIV are activated at stress levels closer to the nominal yield strength and hence may be considered less precarious than HEDE. All three hydrogen-induced damage mechanisms require time allowing hydrogen to diffuse and damage features to incrementally develop. Accordingly, macroscopic cracking occurs with a time delay upon putting the component under stress. Hence, the time-to-fracture is an indicator for the intrinsic hydrogen damage susceptibility of a steel grade.

This parameter is determined by applying a constant stress to a steel sample after defined hydrogen charging, then recording the time until cracking occurs. The longer the incubation time, the more resistant the steel.

Molybdenum alloying to ultra-high strength steels was found particularly beneficial, to making it less susceptible to hydrogen-induced cracking. This was demonstrated in a recent IMOA project, which developed a 2000 MPa presshardening steel to be used for automotive body components. By adding up to 0.5 %Mo to the base alloy, the time-tofracture is increased from around 30 to over 120 hours (Fig 4). Combined alloying with niobium further increases the crack incubation time to over 180 hours.

Numerous underlying physicalmetallurgical effects explain the performance of molybdenum in reducing hydrogen-induced cracking susceptibility: • The molybdenum atom has a high propensity for segregating to grain boundaries, along with the potency September 2021

15/09/2021 11:57:42

32

SPECIAL STEELS

Fig 1. Hot stamped component quenched to 1500 MPa

Fig 2. Mechanism of hydrogen absorption from a

Fig 4. Influence of molybdenum alloying on the de-

strength; occurrence of delayed cracking and brittle

corrosive reaction and recombination of atomic

layed cracking resistance of 2000 MPa press-hard-

character of the crack surface

hydrogen in internal cavity leading to blister

ened steel in hydrogen charging environment

formation.

(notched tensile bar loaded to 90% yield strength)

Fig 3. Hydrogen-induced damage features in martensitic steel. (a) Intergranular fracture; (b) quasi-cleavage fracture; (c) void formation by vacancy condensation Fig 5. Alloy optimization approach for increasing the

to improve cohesion. In that way it counteracts the HEDE mechanism caused by hydrogen atoms aggregating at the same grain boundaries.

• Solute molybdenum being a very large-sized atom interacts with dislocations and vacancies thereby restricting their mobility. Consequently, the HELP and HESIV mechanisms are obstructed.

• Solute Mo atoms act as local hydrogen-trapping sites significantly reducing hydrogen diffusivity.

• Molybdenum can participate in microalloy carbides or even precipitate by itself. The presence of such nanosized particles in the steel matrix acts as hydrogen-trapping sites and obstructs dislocation mobility.

It has been observed for quite some time that molybdenum alloyed ultra-high strength steels show superior performance in applications favouring hydrogen uptake into the steel. This has been evidenced September 2021

Special steel IMOA.indd 3

for high strength steels used in bolts, oil country tubular goods or abrasion resistant components in the form of longer service life or higher applicable service stress. Based on such results, alloy design optimization guidelines (Fig 5) recommend reducing impurities such as phosphorous and sulfur, lowering the manganese content, as well as refining the microstructure by niobium microalloying. Increasing the molybdenum content produces the beneficial effects outlined above. From a hardenability point of view, molybdenum is a preferable alloying element. It is approximately 2.7 times as effective as manganese in suppressing the formation of softer phases.

Therefore, the recommended reduction of the manganese content can be fully compensated with an accordingly smaller molybdenum addition. Last but not least, molybdenum alloying provides excellent tempering resistance ensuring superior combinations of strength, toughness and hydrogen-cracking resistance.

delayed cracking resistance of bolt steel heat treated to 1500 MPa tensile strength (test environment: buffered HCl solution)

Recent research on molybdenum’s metallurgical effects will allow a more precise application of molybdenum in future generations of ultra-high strength steels, ensuring both high quality and cost-effective outcomes. These steels will play a significant role in the continuing general trend of light weighting structures, including making vehicles lighter, safer and more sustainable. As the hydrogen economy continues to grow and is seen as a viable alternative to fossil fuels, there will be a clear requirement for hydrogen extraction and delivery infrastructure, resulting in a substantial demand for hydrogen-resistant steels. Molybdenum alloying offers a highly effective solution to this problem. � www.steeltimesint.com

15/09/2021 11:57:51

33

ROLLING

Integration and digitalization Industry 4.0 technologies have enabled Italian steelmaker Marcegaglia to develop a new modelling approach that has led to the digital integration of the metallurgical processes of hot and cold rolled strip processing. By Alessandro Ferraiuolo* PRODUCT and process development for the automotive sector is mandatory and requires sophisticated mathematical models in order to achieve a metallurgically based design of process conditions. The new frontier, open only a few years ago, in the development of HSLA and AHSS grades, is represented by the digital integration of the processes based on the adoption of a strategy based on a sophisticated combination of predictive mathematical models and advanced process monitoring (epitomised by the Industry 4.0 concept).

With such an approach, it is possible not only to improve the understanding of metallurgical mechanisms but also to control each processing step. Quite recently at Marcegaglia’s Ravenna plant a Master Model project was launched with the purpose of fully digitalizing and integrating all the processes of the plant (from hot rolling and pickling down to galvanizing). The plant adopted an effective and innovative Industry 4.0 vision and one that offered a clear and immediate benefit by digitally integrating the primary process area (hot rolling mill) and the secondary processing area (cold rolling and final annealing). Monitoring steel quality online during production is a major

plus point of digitalisation of this kind as it offers important benefits that enable the full automatization of the plant’s HDG line and optimises the annealing processing conditions, providing the highest productivity rate, improved quality performance and energy efficiency. The key enabler factor to fully digitalize and integrate the aforementioned industrial processes – hot rolling, cold rolling and annealing – was the Tensil-Pro system, which can undertake a non-destructive online evaluation of the tensile properties, in terms of yield stress, tensile strength, work hardening and additional important microstructural features, such as grain size, the austenite phase fraction formed on a continuous annealing line and the martensite volume fraction. The Tensil-Pro system is an auto-adaptive, self training mathematical model in the sense that it does not require time consuming and costly calibration involving laboratory tests of the model parameters. It can be applied to all steels (multi-phase, ferritic and austenitic) and to all other metallic alloys (such as aluminum and copper). At a higher level, MasterModel is a mathematical model that uses continuously all the metallurgical data relevant to each coil including chemical

composition, hot rolled strip grain and tensile properties (Tensil-Pro) giving as an output the optimized HDG cycle. The implementation of ‘Master Model’ in HDG line number four at Marcegaglia Ravenna SpA enabled the facility to achieve set targets in terms of tensile properties, homogeneity and operational efficiency with respect to the whole production route.

Introduction In the last decade, increasing international steel market competition and growing demand for HSLA and AHSS grades of steel, coupled with a need to comply with international environmental regulations, represented the driving force behind finding new solutions to improve steel manufacturing process efficiency. In recent years, a high number of Industry 4.0 projects have been introduced and aimed at developing process automation and improving the efficiency of industrial manufacturing routes thanks to the implementation of advanced mathematical modelling based on the adoption of Machine Learning and Big Data. Metallurgical modelling is, in fact, necessary when a specific and complex microstructure is required together with

Fig 2. Mechanisms of apparent grain growth in HSLA due to intercritical austenite Fig 1. Schematic view of the Tensil-Pro mathematical model architecture.

formation and following epitaxial ferrite grain growth

* Marcegaglia Ravenna S.p.A, via Baiona 141, Ravenna – Italy Email: alessandro.ferraiuolo@marcegaglia.com www.steeltimesint.com

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ROLLING

Fig 3. Austenite fraction evaluated by means of Feral equation (HX340LAD)

Fig 4. Ferrite grain size measured with Tensil-Pro at the HDG line skin pass

Fig 6. Steel grade S320GD: Bold line is the yield stress as a function of temperature; Fig 5. Grain growth due to reverse austenite

tight target tensile properties and validate processing routes for novel steel grades.

Within this framework, a totally digitalized and automatized manufacturing route (the MasterModel project) was conceived and implemented at Marcegaglia’s Ravenna plant. The full digital integration of the industrial processes – pickling down to cold rolling and galvanizing – consists of the development of a high level mathematical model that combines predictive modelling and online monitoring using virtual sensors to define the production process conditions to be adopted in the HDG process. This solution integrates incoming material properties (chemical composition, hot rolled strip properties, reduction ratio), on-line measurements and final product quality targets; it also adjusts the parameters of key process sections accordingly (furnace, zinc bath, air knife) and optimizes product transitions. The project goals were: 1. Full automatization of four HDG lines (one is also a pre-painting line): the output consists of the processing instructions, coil-by-coil, in terms of speed, temperature, September 2021

Ferraiulolo.indd 2

dotted line is the austenite fraction calculated by ThermoCalc

skin pass and leveller parameters. Zinc bath additions and air knife processes are completely automatized and controlled in real time by dedicated mathematical models.

2. Through process continuous product qualification: evaluation of tensile properties combined with microstructural features in hot rolled strip and galvanized strip (Tensil-Pro).

3. Metallurgical investigation: Qualitative and quantitative comprehension of the metallurgical mechanisms affecting the steel properties during industrial production routes. Very fast development time for AHSS or 3rd generation steel products.

The key enabler factor for digitally integrating all the processes (hot rolling, cold rolling and galvanising) was the development and implementation of a virtual smart sensor (tensil-pro) which can monitor in real time the tensile properties of the hot rolled strip and the final HDG products. The tensil-pro system is basically a complex mathematical model implemented

on the first stand of the rolling mill (tandem and reversible) to measure the tensile properties, work hardening and grain size of hot rolled strip. With the same approach, but different equations, tensil-pro is applied to the skin pass process and in this case, in addition to tensile properties and grain size, evaluate the austenite fraction at the exit of annealing treatment (feral equation), work hardening and martensite fraction.

Metallurgical virtual smart sensor: Tensil-Pro The production of AHSS grades for automotive applications requires tight control of strip process parameters and a deep comprehension of the relationship between process parameters and final product properties. In addition to these aspects there is a growing necessity to reduce operating costs and increase energy efficiency and product throughput capability while guaranteeing high-quality products. For Marcegaglia Ravanna, the Tensil-Pro system represented the enabling factor to achieve all these targets for all www.steeltimesint.com

16/09/2021 15:05:59

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ROLLING

Fig 7. HX340LAD - Bold line is the yield stress as a function of soaking temperature;

Fig 8. HX420LAD Bold line is the yield stress as a function of soaking temperature;

dotted line is the austenite fraction calculated by Thermocalc

dotted line is the austenite fraction calculated by ThermoCalc

Fig 9. HDG online work hardening plot evaluated at skin pass (DP780 steel grade)

steel qualities (DQ, EDDQ, HSLA and AHSS).

Tensil-Pro is a metallurgical virtual sensor consisting of a complex mathematical model that enables the plant to evaluate, in real time, tensile properties and the additional metallurgical features reported in Table I. Tensil-Pro can be applied to the hot rolling process (primary area) and cold rolling and annealing lines (cold complex).

Of course, as reported in Table I, the aims and outputs are different. The underlying physical principle of Tensil-Pro is the

Fig 10. HDG online martensite fm/dm ratio evaluated at skin pass (DP780 grade)

continuous evaluation of the stress tensor, work hardening and the distortional energy (stress tensor invariant J2) gathering level 2 rolling mill data in real time. These physical variables can be calculated with quite a high level of accuracy and do not need additional constitutive parameters. The need to introduce constitutive equations only arise when the relationship between stress and strain is considered, for example, when the following explicit function is searched

Process

Hot rolling

1 Tensile properties (yield stress, tensile strength, uniform elongation)

√

Cold rolling HDG/CAL temper √

2 Intercritical austenite fraction and its effect on ferrite grain size (first Feral equation)

√

work hardening d

√

/d

(second Feral equation).

√

3 Martensite in AHSS – fraction/particles size ratio

√

Recrystallized fraction.

√

4 Grain size (reversing Hall Petch equation).

√

√

5 Flow stress at high temperature [10].

√

6 Softening (recrystallization/recovery) and hardening during hot rolling.

√

Table I. List of the metallurgical features that can be evaluated by Tensil Pro.

www.steeltimesint.com

Ferraiulolo.indd 3

where σο is the friction stress, and ξ, ξ’, T are respectively the strain, strain rate and temperature. This behaviour has a fundamental physical reason: the plastic strain is not a state variable and, therefore, is a history or path-dependent process.

To calculate the final state of deformation (and hence microstructural) in a multistep process, such as hot rolling, the deformation path or history must be traced step-by-step. The path-dependent nature of plastic deformation requires that the strain evolution must be treated in differential or incremental form. For this reason, the continuous evaluation of the strain hardening is of fundamental importance because it enables the evaluation of the incremental strain evolution. From these premises it is clear that Tensil-pro can be applied to the hot rolling process as well as the cold rolling or skin pass process in order to measure the metallurgical variables listed in Table I. It can be applied to all steel grades (ferritic and austenitic) and metallic alloys. The effect September 2021

16/09/2021 15:06:06

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allows the widest product mix from mild steel IF, ULC, up to AHSS steel grades for automotive applications, in thin gauges down to 0.8 mm as a substitute for cold-rolled strip products.

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DDM - DANIELI DIGIMELTER: THE EVOLUTION OF THE EAF

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SCRAP MANAGEMENT AND ENDLESS CHARGE

Additional digital overall plant optimization

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ROLLING

Fig 11. DP780 microstructure at the head position

Fig 12. DP780 microstructure at the tail position

Fig 14. Comparison of the yield stress of the same coil hot rolled (S460MC) and after Fig 13. Yield stress of hot rolled (S355MC) and cold rolled-HDG (S320GD) products

of strain rate, temperature and chemical composition, must be considered through additional constitutive equations with parameters that are material-dependent.

The parameters of constitutive equations can be determined for each steel grade by means of the standard least square method if enough laboratory microstructure and tensile test data are available. More recently, within the framework of the Master Model project, a new algorithm was developed. The self-training unit algorithm (based on an unsupervised ML approach), automatically evaluates all the parameters without any laboratory tensile test. The automatic evaluation of the model parameters allow the Tensil-pro to became a true auto-adapting model because even if an important change occurs in the plant in terms of instrumentations, lubricating mixtures, roll surface finishing, the recalculation of the model parameters can be carried out in a very fast and automatic mode. The implementation of the self-training algorithm also means that the Tensil-Pro can be put in operation September 2021

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cold rolling and galvanising (S420GD)

immediately within a few hours of work.

Fig 1 Virtual smart sensor applications to cold rolling process In addition to standard tensile properties evaluation, the developed virtual sensor can give additional information such as the ferrite grain size, recrystallized fraction and the amount of austenite phase fraction formed at the end of intercritical annealing treatment. This latter metallurgical parameter represents a quite new and interesting opportunity mainly for the investigation implications and for understanding the process-product relationship. In the next sections I will show some interesting results of these applications of Tensil-pro.

Intercritical austenite phase fraction In this section is presented the theory to evaluate the austenite fraction formed during an intercritical annealing process (Fig 2). The basic assumption of the theory is that the reverse austenite-to-ferrite

transformation is assumed to occur mainly through ferrite epitaxial growth. This assumption can be considered valid if the cooling rate of the strip after soaking is in the range 10-50°C/s. Fig 2.

It was demonstrated elsewhere [1,7] that a differential equation exists (first Feral equation) relating to the time derivative of the austenite fraction at the furnace exit with the evolution of the ferrite grain size after the cooling section down to room temperature: (1) Integrating this equation and assuming the initial and final ferrite grain size respectively drex (grain at exit furnace) and dα(t) (after cooling section). Concerning the austenite fraction the integration boundaries are Xγexit furnace (t) and Xγafter cooling (t). It is possible to distinguish two cases: i) Xγexit furnace (t) > 0 Dual phase steel ii) Xγafter cooling (t) = 0 No austenite/martensite

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ROLLING

Fig 16. Schematic view of the hot and cold processes Fig 15. Effect of soaking temperature on DP600 tensile properties in HDG line

The first case to be treated in the next section is relevant to online work hardening evaluation and consequent martensite fraction evaluation. The second case refers to steel products without residual austenite or martensite. In this case we can write: (2) The recrystallized grain size drex and the grain size dα(t) after cooling (fig 3) are calculated according to the method described in [1, 2]. This methodology is implemented with the Tensil-pro model in order to give a continuous online evaluation of the austenite fraction. Fig 4 shows the reported austenite fraction calculated with the Feral equation (2) on a coil of steel grade HX340LAD. In the same plot the strip soaking temperature is also reported.

It is quite astonishing that the results fit quite well with the thermodynamic value calculated by Thermocalc. This result confirms that during annealing treatment (about 800°C) the austenite phase fraction achieves the thermodynamic equilibrium (Fig 6).

Effect of intercritical austenite fraction on final ferrite grain size The Feral equation (1) correlates the austenite fraction with the ferrite grain size evolution. If the thermodynamic equilibrium is reached during the annealing treatment the amount Xγexit furnace (t) can be evaluated by means of Thermocalc and, therefore, the solution of equation (1) can be written: (3) This equation quantifies the effect of austenite reverse transformation on final ferrite grain size and reveals that at larger IC September 2021

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integration

austenite fractions (i.e. at a higher soaking temperature), the effective final ferrite grain size becomes significantly larger, much more than could be expected if normal grain growth was the only mechanism operating during the soaking. This effect is plotted in Fig 5 where is shown the curve dα vs Xγ for different recrystallized grain size drex. In order to verify the predicted behaviour, the yield stress was plotted as a function of soaking temperature for three different steel grades: S320GD (C-Mn), HX340LAD (Nb added) and HX420LAD (Nb added). This analysis was based on an industrial database i.e. on very high number of tensile tests (more than 1000) for each steel grade investigated. In Fig 6 the behaviour of steel S320GD is shown at different temperatures. As illustrated the yield stress decreases by about 10MPa for an increase of temperature of 80°C. For this temperature range the austenite would experience a change of 30%. From Fig 5 this variation of austenite should produce an increase of final ferrite grain size of 1.6µm. From the Hall-Petch equation, assuming K=22 and σ0 = 80 MPa, in correspondence with a grain growth of 1.6 µm we obtain a variation of about 15MPa, which aligns pretty closely with the prediction of the feral equation.

Fig 7 reports the behaviour of the HX340LAD microalloyed steel. For a temperature variation of∆T=40°C (760800°C the austenite phase fraction increases by about 10%. According to Fig 5 the ferrite grain size increases 0.5 µm.

If we assume the Hall-Petch relationship with K=22 and σ0 =120 MPa we found a decrease of yield stress of about 25MPa. The steel grade HX420LAD is more sensitive.

A variation of soaking temperature of 40°C would produce a variation of yield stress

of 50MPa! These results confirm that the final tensile properties are strongly affected by the IC austenite fraction and the steel chemical composition (C, Mn content) plays a key role.

Theory of online work hardening measurement The full description of the plasticity behaviour of a metallic material requires knowledge of the work hardening. Work hardening is a fundamental property that is strictly related to fundamental metallurgical and microstructural characteristics of the material, such as stacking fault energy (SFE), grain size and second phases features. In this section the theory to evaluate in real time the work hardening with Tensil–Pro will be presented. The new approach starts with Orowan’s longitudinal equilibrium equation: (3) In which f is the longitudinal force for unit width, S is the pressure due to roll separating force, and R’ deformed radius, ϑ is the contact angle. The ‘+’ sign is valid in the zone between the neutral plane and the exit plane of roll bite, the minus ‘-‘ refers to the entry zone. The term µslip is the effective friction co-efficient and is evaluated by the online measurement of the forward slip.

From the plasticity theory it is well known that in a multi-axial stress state there exists a relationship between the flow stress and the principal stresses. Under plane strain condition we assume the following yielding criteria: (4) In which σF is the flow stress of the rolled material and h is the average strip/plate www.steeltimesint.com

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ROLLING

thickness in the roll bite. Substituting the (4) in (3) we found the following equation relating the work hardening as a function of the rolling process parameters: (5) Where is the inverse of the deformation gradient along the contact arc. The term represents the slope of the normal stress in the roll bite. From the above equation, it arises that this term is constituted of two contributions: one related to ‘friction hill’ and the second to work hardening of the strip/plate. Passing to finite difference the above equation can be simplified assuming that the neutral plane is coincident with the exit plane. Under these assumptions the equation (5) can be rewritten as follows (second Feral equation [5, 10]): (6) Where S is the average normal pressure due to separating force, ∆ϑ is the total contact angle, ∆ε is the strain of i-th pass, ∆S = Sentry − Sexit is the variation of normal stress between entry and exit plane. In the present paper it was assumed that Sentry is the flow stress of the strip at the entry of the i-th pass. The equation (6) can be used to evaluate the strength factor K(T) assuming a Hollomon power law relationship between stress-strain. This is necessary in order to calculate, for each rolling pass, the strain path and to evaluate the fraction of total strain that is effectively retained during the hot rolling process.

On-line martensite evaluation in AHSS To obtain improved forming ability, especially stretching ability, a high strain hardening must be targeted and for this reason it is quite important to understand how the process parameters control this feature. It is well recognized that in AHSS the volume fraction (fm) and size (dm) of the MA constituent are strictly related to work hardening. This means that a higher MA fraction and/or finer MA particles can significantly improve the maximum uniform strain and hence the product forming ability. These metallurgical features are related to steel chemical composition, intercritical annealing temperature and strip cooling pattern after furnace. The possibility of evaluating strain hardening behaviour during the skin pass process (equation 6) allows the evaluation of ratio fm/dm www.steeltimesint.com

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according to the following equation due to Ashby [4]: (7) Where b is the Burgers vector, ε is the applied strain, G is the shear modulus and k is a constant to be determined.

This equation showed in many papers to be in agreement with the observed work hardening rates at martensite fraction levels ranging between 0.2÷0.3.

Another advantage using this approach is represented by the higher sensitivity, with respect to flow stress, of the work hardening rate on microstructural variation.

Fig 9 shows the plot of yield stress along with the work hardening of a DP780 steel grade during skin pass processing at HDG line n.4 calculated applying the equations (6-7). As expected, the yield stress and work hardening have the same trend, but with a quite different slope and sensitivity. The significant increase of work hardening in the second half of the coil is not related to any change of HDG speed line or soaking temperature, but is related to hot rolled strip microstructure.

This again confirms that, to understand the metallurgical behaviour of AHSS during the final annealing process, it is fundamental to have knowledge of the hot rolled strip’s tensile properties and its microstructure. In Fig 10 is reported the calculated martensite f/d ratio together with the work hardening evolution for the entire strip length. In Figs 11-12 are shown the strip microstructure respectively in the head and tail position. The difference in terms of ratio fm/dm is because of a finer structure detected in the tail. For this reason, online evaluation of work hardening must be considered the key enabling factor for continuous quality assessment and for understanding the effect of process conditions on product microstructure.

Integration of hot and cold rolling process by means of Tensil-Pro From a metallurgical perspective, it is well recognised that hot rolled strip microstructure influences profoundly the microstructure and tensile properties of the products after cold rolling and final annealing. The basic physical reason for this is related mainly to precipitation behaviour in terms of AIN and (Nb, Ti)CN and grain size evolution during the hot rolling process. The big metallurgical issue is that

41

grain size and precipitation behaviour are coupled and cannot be easily evaluated by classic empirical models because the strain path history during hot rolling and the necessary additional constitutive parameters are all unknown. On the other side the production of AHSS and HSLA steel grades, for high demanding applications, requires tight control of the hot/cold rolling process and a deep understanding of the relationship between process parameters and final product properties. One clear and immediate benefit of the digital integration (MasterModel project) of primary area processes (hot rolling) and downstream processes (cold rolling and annealing) is certainly the advantage of monitoring steel quality online during production.

This real-time reaction possibility has important benefits that enables the full automatization of the HDG/CAL line, the optimization, coil-by-coil, of the quality performance and energy efficiency of the processes. Fig 13 reports the comparison between hot rolled (S355MC) and galvanised strip (S320GD) produced in about six months. The hot rolled tensile properties and grain size are calculated thanks to Tensil-Pro implemented in the first stand of the cold rolling mill (both tandem and reversible mill). The tensile properties of HDG products are evaluated thanks to the Tensil-Pro system implemented in the skin pass. As it can be noted there is quite a strong relationship between hot rolled and cold rolled products. This strong relationship can be detected, very clearly, within a single coil, making it possible to investigate, with a surprising resolution, very detailed phenomena occurring in the hot rolling process and their evolution in the final galvanised product. Fig 14 illustrates the yield stress of the same coil in a hot rolled state and after cold rolling and annealing (HDG line). The yield stress of hot rolled strip reveals the presence of regular peaks that are related to the skid marks effect during slab reheating. This represents a sort of a finger print on the slab and then on the hot rolled strip. It is well known that the skid mark produces a small difference in the slab reheating temperature that yields to a significant difference in the dissolution and re-precipitation of (Nb, Ti) CN during hot rolling process. In the case reported in Fig 11 the overall difference in terms of yield stress, due to skid mark, is in the range of 20-40 MPa. On more specific applications this small variation of September 2021

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ROLLING

flow stress could lead to non-compliant properties such as, for example, oil and gas products, which have high demanding toughness. It is quite astonishing to see that the same features are still visible in the final cold rolled product, even if slightly reduced in intensity.

It is worthy to note that the presence of walking beam skid marks and the relevant uneven tensile properties are not detected by all steel suppliers. This means that in some cases, slab reheating countermeasures are taken to avoid this occurrence.

Another quite interesting application of Tensil-pro is the evaluation of the processproduct relationship. This is particularly important for AHSS production. Also in this case the comparison between hot rolled strip properties and final properties is fundamental in order to understand the effective role played by HDG processing conditions (annealing temperature, speed, etc) and the inheritance from the hot rolling process. Fig 15 plots the soaking temperature evolution of a DP600 and the relevant yield stress profile in hot rolled strip and final HDG product. These plots are very useful and important because from these it is possible to evaluate quantitatively the effect of temperature variation on microstructure evolution and tensile properties directly on the industrial plant conditions. Fig 16, shows the proposed schematic architecture of the global model that can integrate hot rolling and downstream processes. The key enabler factor is, therefore, the implementation of virtual smart sensors (Tensil-Pro) in several strategic processes: hot rolling mill (roughing and finishing), cold rolling and skin pass. The virtual smart sensors continuously measure the metallurgical characteristics allowing the realization of through process mathematical models that can understand and/or investigate the effective role played by each process parameter on the final properties.

Conclusions This paper has presented the benefits and some results relevant to the implementation of a new modelling approach offering the possibility to realize the digital integration of the metallurgical processes of hot rolling with the cold rolling mill complex manufacturing route (MasterModel project). The focus was focused on the online monitoring of the tensile properties and microstructure September 2021

Ferraiulolo.indd 7

evolution of hot rolled strip as well as during cold rolling and HDG processing.

The key enabling factor that allowed us to achieve the above goal was the Tensil-Pro mathematical model that evaluates online and continuously the tensile properties, work hardening, intercritical austenite fraction, martensite ratio, and grain size. The MasterModel project allowed us to achieve a very tight monitoring of hot/cold processes and to achieve a deep comprehension of the relationship between process parameters and final product properties. These results produced two big benefits: the real-time reaction enabling a full automatization of the HDG line. The second benefit is the coil-by-coil optimization of the annealing processing conditions, highest productivity rate, quality performance and energy efficiency of the processes. The MasterModel allows us to shift from the manual management of the key processes of the galvanizing lines – generally based on manual presets or individual models for each process – to a totally automatized process aimed at reaching the best compromise between quality yield, productivity and operational flexibility. The results achieved are quite interesting and MasterModel could be used to introduce online adjustments to the hot rolling schedule in order to optimize productivity and improve final strip quality and mechanical performances.

From these premises, a significant competitive advantage is expected due to lower manufacturing costs and improved capability to fit the most stringent expectations and technical specifications of European end users. More recently this methodology has been implemented in the hot rolling process to realize a ‘Smart Rolling’ process in which the smart sensors’ results can be used for online adjustments in accordance with specific feedback algorithms in order to optimize productivity, final strip/plate quality and mechanical performances of high strength steels. Until now there has been very little in the way of published data correlating hot and cold rolled tensile properties comparing the whole length of the tensile properties on industrial plant. The tensile properties of hot rolled strip (yield stress, strength, work hardening and grain size) are evaluated with the implementation of a mathematical model (Tensil-Pro) installed at level 2 of the first stand of two cold rolling mills at the Ravenna works (tandem

and reversible mill). The comprehension of the metallurgical inheritance of the hot rolling process is quite important in order to build a fully integrated picture of the whole process and calculate the final properties. The complementary results of Tensil-Pro gathered during the galvanising process have allowed us to fully understand and quantitatively evaluate the effect of metallurgical mechanisms occurring during the high temperature annealing process.

The effect of reverse austenite-to-ferrite transformation on the final ferrite grain size and, therefore, the final tensile properties, were evaluated quantitatively. � References 1.

Ferraiuolo A., New approach for calculation of the

austenite fraction formed during continuous annealing of HSLA/AHSS steel grades; International Congress Galvatech 2021, June 2021.

2.

Ferraiuolo A., Investigation on Softening/

Hardening Mechanisms in Hot Rolling Process by means of Advanced, Self-Training, Virtual Smart Sensors, International Congress AISTECH 2021.

3.

Yoshie A , Fujioka M , Watanabe Y , Nishioka K , ‘

Modelling of microstructural evolution and mechanical properties of steel plates produced by thermomechanical control process ’, ISIJ Int. , 1992 , 32 , 395 – 403 .

4.

Park S H , Jonas J J , ‘ Mathematical modelling of

CCP (continuous-cooling precipitation) diagrams ’, Proc.

Int. Symp. on Mathematical Modelling of Hot Rolling of Steel, ed. by Yue S , CIM , Hamilton, Ontario , 1990 , 446 – 456.

5.

Senuma T. , Takemoto Y., ISIJ International, Vol. 48

(2008), No. 11, pp. 1635–1639.

6.

M.F. Ashby, The deformation of plastically non-

homogeneous materials, Philos. Mag. 21(170)(1970) 399-424.

7.

Ferraiuolo A.; New approach for online tensile-

structure properties evaluation on HSLA/AHSS steel grades, La Metallurgia Italiana, Marzo 2020.

8.

Estrin Y , Mecking H ( 1984 ), Acta Metall , 32 , 57

– 70.

9.

Mecking H , Kocks U F ( 1981 ), Acta Metall , 29 ,

1865 – 1875.

10. Sellars C. M. and Whiteman J. A., Met. Sci., 13 (1979), 187.

11. Ferraiuolo A., New stainless TWIP steel Fe-17CrMnNiCu: mechanical properties characterization and microstructure evolution during deformation; La Metallurgia Italiana - n. 3, 2017.

12. Ferraiuolo A. , Investigation on softening/ hardening mechanisms occurring during hot rolling process by means of new advanced, self training smart sensors; International Congress AISTech 2021, June 2021.

13. Ferraiuolo A., Patent N. 102021000008636, IPO, april 2021.

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ELECTRIC STEELMAKING CoJet burners firing uniformly around the furnace

25 years of CoJet technology for the EAF The introduction of Linde’s CoJet coherent injection technology 25 years ago is now adopted by over 170 EAF operators resulting in greater efficiency of operations and thereby a reduction in CO2 emissions, a factor further enhanced by the system being ‘H2 ready.’

IN September 1996. Gerdau MacSteel at Fort Smith, Arkansas, was the first steelmaker to install a CoJetTM Gas Injection system in its 60-ton electric arc furnace (EAF), replacing conventional manual lancing with the new concept of a wall mounted multi-functional fixed burner/lance system. Twenty five years later, in January 2021, fellow group steelmaker, Gerdau Steel in Midlothian, Texas, installed three CoJet systems in its 150-ton EAF. In this 25-year period, 172 furnaces have installed CoJet technology across the continents of the world, in North and South America, in Europe and Asia.

Coherent jet injection technology was conceived in the USA by Praxair. Praxair merged with Linde of Germany in 2019 to form Linde plc. This new breakthrough technology, named CoJet, was a significant step in injecting chemical energy into an www.steeltimesint.com

Cojet.indd 1

EAF in an efficient manner. It was the first to introduce the concept of fixed wall mounted injectors, with each injector designed to perform multiple functions, incorporating an oxyfuel burner, oxygen lancing, post combustion, and carbon injection.

“That the CoJet programme has been a success, is clearly evident”, says Pravin Mathur of Linde, who pioneered the implementation of CoJet technology in electric arc furnaces. “The testimony to its wide acceptance in the EAF melting process can be summarised as follows”: • Over 170 furnaces authorised to operate this technology worldwide over the past 25 years, and perhaps twice as many additional furnaces using a similar concept; • A wide geographical distribution with customers in North and South America, Europe, and Asia;

• Furnaces ranging in capacity from 30 to 400 metric tonnes tap weight; • The number of injectors installed per furnace ranging from one to five; • Various furnace types including AC, DC, Shaft, Consteel and Conarc; • Raw material input to the furnace with wide ranging variation – 100% scrap, 100% DRI, a mixture of scrap and DRI, various percentages of hot metal, continuous scrap feeding; • Furnaces operating under constant flat bath conditions with continuously varying bath heights; • Inherent burner capacity of 3MW to 6MW per injector; • Designed oxygen lancing from 600Nm3/h to 4750Nm3/h; • A wide spectrum of oxygen practice from 12Nm3/ton to 55Nm3/ton.

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Fig 1. A flame shrouding the supersonic jet of oxygen extends the length of its coherency to 70 times the nozzle diameter

The technology Exploratory research on supersonic gas jet behaviour by Linde’s corporate fellow, Dr John Anderson, first led to the concept of flame-shrouded jets. These become coherent and maintain their exit velocities and momentum over long distances. For example, an optimum flame shroud extends the length of a Mach 2.0 supersonic oxygen jet in ambient air from around 15 times the nozzle diameter to about 70 times the nozzle diameter (Fig 1).

In an EAF, the laser-like oxygen jet from a coherent injector travels significantly farther than an oxygen jet from a conventional supersonic lance. Hence, coherent jet injectors can be positioned well above the bath in the sidewall of the furnace, and still carry out effective bath lancing. Also, when the coherent jet of oxygen produced by the nozzle impinges and penetrates through the slag and into the molten steel bath, the concentrated momentum of the oxygen jet dissipates in the steel as fine bubbles, providing deep penetration and effective slag-metal mixing. This results in high efficiency lancing and decarburisation.

The CoJet injector assembly, in addition to lancing, is also designed to provide multiple functions. Each injector also functions as a burner to melt scrap and to simultaneously inject supplementary oxygen at subsonic velocity for post combustion.

The post combustion oxygen is introduced in a controlled fashion at a specific shallow angle and close to the main lance oxygen to achieve maximum benefits, not only during scrap melting, but also during flat bath periods. This results in a further reduction in electric power consumption, and an increase in furnace productivity.

The CoJet injector assembly (Fig 2) also incorporates a feature to introduce carbon.

The carbon is injected in a fully automated September 2021

Cojet.indd 2

Fig 2. CoJet assembly mounted on the furnace shell.

mode through a port specifically located to allow for effective slag foaming and reduction. Under proper conditions, this injected carbon can also provide some recarburisation of the bath. The benefits resulting from this efficient mode of carbon injection is the excellent slag foaming achieved, with a significant reduced quantity of injected carbon used.

Gas requirements CoJet technology is fuel flexible in that a wide range of hydrocarbon fuels can be used for the burner and shrouding gas.

Natural gas, desulphurised coke-oven gas, LPG, kerosene, and fuel oil have all been commercially deployed.

Linde has also developed CoJet using hydrogen as the shrouding gas and burner fuel. “Hydrogen is in fact an ideal fuel to produce coherent jets,” said William Mahoney, who spearheaded the use of hydrogen, while leading the development of coherent jets in applications other than the EAF. “Not only does hydrogen produce the longest coherent jets for oxygen lancing (greater than 85 times the nozzle diameter), it also improves the heat transfer efficiency for scrap melting”. The existing CoJet burners can be easily used with hydrogen with minimal modification (Fig 3).

Given the high temperature atmosphere in an EAF, questions are periodically raised by customers about the need for a shrouding fuel to produce coherency.

While hot ambient conditions do improve jet lengths of a conventional O2 jet, up to about 35 nozzle diameters, laboratory studies and field experience has shown that they do not produce jet lengths comparable to a perfect coherent jet (>70 nozzle diameters). In addition, the jet length is not consistent throughout the heat, and leads to negative impacts on furnace

operation especially when the bath height changes through the heat based on type of operating practice and general refractory wear (Fig 4).

The purity of oxygen required is less stringent than for a BOF and can be produced by Vacuum Pressure Swing Adsorption (VPSA) in which most of the nitrogen is ‘filtered’ out of the air by molecular ‘sieves’ resulting in a gas containing 90-92% oxygen and 4% argon.

This is a lower cost method than cryogenic liquification of air.

Operational features and benefits A typical CoJet system includes multiple injectors with associated assemblies for mounting on the sidewall of the furnace, a valve skid to independently meter and control the oxygen and fuel, a programmable logic controller, and an operator station usually located in the furnace pulpit.

Historically, conventional EAF operation had been carried out by manual lancing and carbon injection, usually through an open slag door. By using coherent jet technology, the furnace is converted from a manual operation to a fully automated sequenced operation with the slag door closed. In addition, the oxygen and carbon are now uniformly introduced through multiple injectors around the furnace in a homogeneous manner as shown in Fig 5. This allows for the use of higher overall chemical energy and improved safety for the operators.

CoJet coherent jet technology provides a fully automated sequenced operation.

Once a bucket charge is added and the roof closed, the injectors automatically begin to operate in their pre-programmed sequence. With staged firing profiles, the injectors operate to provide different flame www.steeltimesint.com

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ELECTRIC STEELMAKING

Fig 3. Hydrogen is the ideal fuel for the shrouding flame as it produces even longer coherent jets of over 85 times the nozzle diameter

shapes. Initially, the injectors function in a low burner mode to melt the scrap. At this stage, a wide flame is used to heat a large area of scrap. Subsequently, a high burner mode is used with a more cutting or penetrating flame, followed by a low lance cutting mode that is deployed to rapidly cut through the heated scrap and facilitate rapid melting. After the scrap is melted with this sequenced burner/ low lance cutting operation, the injectors automatically switch to high lancing and decarburisation. Concurrently, carbon injection is automatically initiated to inject carbon at set flow rates. Throughout this run, the post combustion oxygen is continuously added, the flow rate modified for each mode of operation of the injectors; ie low burner/high burner/low lance/high lance-refine. This allows for a high rate of utilisation of the CO evolved during the heat, and its combustion to transfer energy to the bath.

A furnace operated with CoJet can immediately reap benefits. Typical cost savings derived are from a combination of the following parameters: • Reduced power consumption • Increased productivity • Elimination of supersonic lances and manipulators • Significantly reduced maintenance • Improved yield • Reduced refractory wear at banks • Reduced gunning • Reduced electrode consumption • Reduced injected carbon • Improved delta life Some of the other factors that lend added value to using a coherent jet technology are: • Automation – less operator dependent www.steeltimesint.com

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Fig 4. Coherent jet length with and without shrouding

Variable

Before Installation

After Installation

% Change

Tons / hr

105.5

112.2

6.3

Delays hr

2.68

1.99

-25.7

Tap-to-tap mins

65.44

54.5

-16.7

Power kWh/t

426.1

396.9

-6.9

Electrode loss kg/t

1.97

1.66

-15.4

Delta refractory life

88.74

219.2

147.1

Oxygen Nm3/t

19.2

29.7

54.8

Natural gas Nm3/t

5.6

8.2

46.4

All data are per metric ton of good billet.

Table 1. Average actual savings in a 125 ton AC furnace with three CoJets

• Consistency – from heat to heat • Improved slag foaming – higher rate

of power input • Non-water-cooled injectors – easy to check • Total flexibility – option to selectively

lance with any injector(s) • Improved safety.

Table 1 illustrates average actual savings in a 125 short ton AC furnace with three CoJet injectors.

“With over 170 furnaces around the world authorized to use CoJet technology, considerable knowledge has been garnered at Linde from their experiences with a wide range of furnace types and operating practices,” said Sumant Warty, who leads the worldwide commercialization of CoJet technology at Linde.

Jet characteristics Coherent jets can be designed for remote location on the sidewall even as high as 1.85m above the bath. CoJet offers coherency of the jet, at supersonic speeds, up to 2.5m in length from the nozzle face.

This factor becomes even more critical when furnaces are operated with hot metal, 100% DRI feed or continuous feeding of

scrap. Under these conditions, the furnaces are in a flat bath condition all the time and the bath height changes significantly over the extent of the heat. Under such conditions, it becomes critical to have accurate quantitative data on jet length.

This helps ensure that a truly coherent jet is designed with the appropriate requirements, and with its characteristics maintained over the requisite distances.

Well-designed coherent jets can function effectively in such furnaces with continuous feeding, or even in furnaces where there are bath height changes due to bottom wear.

It is critical to have quantitative data on coherent jet length and ‘perfect’ coherent jets to handle variations in bath height without splashing or creating negative effects on the furnace. Imperfect coherent jets, when installed in such furnaces, can render considerable damage to the furnace and negatively impact the operation. Typical problems that can be encountered with poorly designed coherent jets are: • Excessive splashing • Excessive overheating of panels • High delta wear • High refractory wear • High levels of FeO • Poor yield September 2021

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Fig 5. CoJet System: General layout and scope of supply

Another key aspect of coherent jets is the shroud ports, which are integral to the injector design. Maintaining the appropriate gas flows through the flame shroud (fuel gas and shroud oxygen) is critical for proper operation in each of the modes. If the flows to the shroud ports are not independently controlled, the integrity of the coherent jet can be compromised during a campaign.

Such occurrences lead to negative effects on the furnace, some of which are listed above.

Sometimes customers in countries with high fuel prices request that the coherent jet offer be made without using a shrouding fuel. As indicated in Fig 4, this is not advisable, and it results in excessive splashing, loss in yield, longer heat times, increase in O2 consumption due to lower injection efficiency, and significantly higher carbon injection consumption to combat raised FeO levels. The effects of flame shrouding on the penetration length of a supersonic oxygen jet are huge. While, relative to ambient air, the hot furnace gases increase the natural jet penetration length, the application of a flame shroud maximises the coherent jet length to more than double the length inside the hot furnace.

Lancing efficiency and carbon When lancing with coherent jets, the decarburisation efficiency improves considerably. This becomes a useful tool to reduce refining times, improve productivity, and make gains in power savings. Generally, carbon injection with the CoJet system has demonstrated that best results are achieved with additions of less than 5-8 kg/ ton. With the slag door closed, the foamy slag generated can be retained and carbon injection proportionally reduced or stopped.

Reduced injected carbon of up to 60% September 2021

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Fig 6. Inverse ratio of EAF power applied versus oxygen consumption

achieved in some cases. In addition, since the ingress of air is curtailed when the slag door is closed, NOx emissions that form in the vicinity of the arc are reduced.

The improvements in jet penetration, uniformity of lancing around the furnace and better slag foaming also result in lower nitrogen levels in the steel. Reductions up to 10 ppm have been achieved, both in scrap and DRI charged furnaces.

Maintenance A frequent concern of any melt shop is the kind of attention and the level of maintenance necessary for any new system and hardware installed. This aspect is crucial since any down time needed to carry out maintenance, comes at a price.

The injector itself requires no cooling water and weighs barely 13kg. A quick inspection of an injector takes about 10 minutes. Generally, such an inspection is advised at least once a week on a down day to ensure the integrity of the nozzle face. A notification in the operator station is available to alert the operator, in case any specific changes occur.

Another key benefit from a maintenance perspective is the life of the coherent jet injector. Experience shows, provided adequate cooling water is maintained, basic flows and pressures of oxygen and fuel are held and sustained in the various modes – especially during charging, the injector life is significant.

Customers have been using CoJet injectors and panels for more than a year, and in some cases, over 18 months.

Sustainability In recent years the EAF’s lower carbon footprint has grown increasingly important compared with the integrated blast furnace – basic oxygen furnace (BF-BOF) route. For

an EAF charging 100% scrap, a reduction in energy requirements as high as 75% can be achieved, and scrap is defined as carrying zero CO2. CO2 emissions from an EAF charging 100% scrap are in the order of 0.33tCO2/tonne of steel produced.

Over the past 25 years, global EAF output has doubled from 246Mt to 494Mt. However, the share of EAF global steel production has fallen from 33% to 26% over this period, reflecting the vast expansion of steel output from China using the BF-BOF route, with EAF production here accounting for only 9% of output in 2020.

The ratio of EAF to BF-BOF production is generally much higher elsewhere; 42% in Europe and Asia (excluding China), and 70% in NAFTA countries, in 2020.

Total CO2 emissions are dependent on the carbon emissions relating to electricity generation, the fuel gases used in burners, electrode consumption, carbon injection, and so on.

If quality requirements demand part charging of primary iron such as DRI, pig iron or hot metal, the CO2 emissions increase. Indeed, it is impossible to reach zero emissions in any steelmaking process since the steel itself requires carbon as an alloying element. Even DRI produced with 100% hydrogen requires carbon to passivate it to avoid spontaneous combustion on exposure to moisture, unless directly linked via an inert conveyor to the EAF. The ability of CoJet technology to use hydrogen as the fuel for shrouding and for burner flame without major conversion of the hardware readily lends itself as a ‘H2 Ready’ application for the steelmaking process and one that will further lower the CO2 footprint of the EAF once ‘green’ hydrogen can be supplied at a commercial price. www.steeltimesint.com

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ELECTRIC STEELMAKING

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Other applications of CoJet CoJet technology has been demonstrated in the basic oxygen furnace (BOF) replacing the top lance with a CoJet system. The greater penetration and smaller area of impact of the CoJet coherent flow of oxygen resulted in less splashing, improved mixing of metal and slag, shorter blowing times, reduced slopping and improved efficiency of oxygen use. In trials, the degree of stirring was similar to that achieved using bottom stirring through porous plugs. The amount of slopping fell from 50% when using a conventional lance, to 20% with CoJet. In addition, heavier scrap can be included in the charge, FeO is lower, resulting in improved yield, and refractory wear is less. From a quality point of view, there is reduced nitrogen in the steel. The CoJet top lance can potentially be used in burner mode for scrap preheating to help increase scrap charged to the BOF. Non-ferrous applications A lower pressure (145 kPa) version of CoJet has been applied in a copper smelter using Inco’s MK ‘top blowing, nitrogen bottomstirring converter’. A marked improvement in the efficiency of oxygen utilisation was achieved through a reduction in ‘horn’ formation at the lance tip, which has stopped the need for midcharge lance tip cleaning thereby increasing productivity. Cleaning is still required at the end of each charge, but the task is now much easier and quicker.

At Rio Tinto Kennecott in the USA, CoJet technology has been installed to speed up melting of scrap copper in the anode-refining furnace, and also achieve rapid sulphur removal by oxidation. The lancing capability of the process further helps to remove hearth accretions.

The increased scrap melting capacity in the anode furnace is growing in importance worldwide in support of minimising CO2 efforts.

Conclusions and outlook The past 25 years have seen a dramatic increase in the production of steel in the electric arc furnace with a growth in furnace heat size coming close to that of many BOF converters (Fig 6). To alleviate longer tap-to-tap times for refining resulting from the shallower hearth of the EAF compared with the BOF, steelmakers are searching for means of speeding up reaction rates in the EAF. CoJet technology has proved to be an excellent way of achieving this goal. As the proportion of EAF steelmaking increases with the move to decarbonise steel production, CoJet technology becomes of even greater significance in the drive to support this decarbonisation roadmap.

“The introduction of CoJet 25 years ago changed the industry standard completely, created many learnings that yielded further operational improvements, and formed a platform for the future.

CoJet is ‘H2 ready’, but there are also a number of other interesting developments with ‘fluidic burner’ and multi-injection, which will make a great technology even greater going forward”, said Joachim von Scheele, who carries the overall responsibility for commercialisation of Linde’s technologies to the steel industry.

“CoJet is an excellent example of how Linde has been making the world more productive, but it is also providing a tool for decarbonisation available today and ready for the future,” Scheele concluded. � www.steeltimesint.com

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Cokemaking Services

Coal blend optimization We are indeed proud to look back upon more than sixty years of research and development in the field of cokemaking.

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September 2021

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COATING

Responsive control for hot dip galvanizing With zinc prices already exceeding pre-pandemic levels – at USD3,000/t1 – and predicted to rise further over the coming decade2, there is growing economic motivation for the precise control of hot dip galvanizing (HDG) processes. By Chris Burnett* CONTINUOUS HDG, with zinc and zinc alloys, is an efficient technology for galvanized steel strip production. Profitability relies on consistently meeting product quality targets by ensuring a uniform coating of adequate thickness, with minimal excess. Applying just enough zinc to meet product specifications is the goal.

Hot dip zinc coating weight is verified using the Weigh-Strip-Weigh (W-S-W) process, in accordance with ASTM A90 or ISO14603,4, but these are lab-based analyses performed after a finished coil of coated strip exits the mill. The requirement for measurement within the process, to inform process control, has long been recognized, and most producers deploy online x-ray fluorescence technology to measure coating weight towards the ‘cold’ end of the process, once the coated strip has cooled. ‘Hot’ coating weight gauges are an important further evolution with respect to improving the control of HDG, allowing measurement far closer to the zinc pot, and by extension, more responsive process control.

In this article, we consider the benefits of hot coating weight measurement examining its potential to deliver enhanced control,

Fig 1. Schematic of an HDG line showing the installation of cold and hot coating weight gauges

tighter manufacturing tolerances and faster product changeover times. Estimates indicate that the use of hot coating weight gauges can have a major impact on process economics with experience suggesting that projects typically deliver a payback time in the region of six months.

Controlling hot dip galvanizing A schematic of a continuous HDG process is shown in Fig 1. Cleaned, annealed steel strip is fed through a zinc pot, a bath of molten zinc typically operating at a temperature of around 460oC. An air knife blows excess zinc from the surface of the exiting strip to ensure a uniform coating, with air knife position (distance from the strip and angle to it) and applied air pressure directly impacting the amount of zinc removed. These are the primary levers for coating weight control.

Once through the air knife the coated strip is cooled, typically via passage through a cooling tower, prior to post-production processing (where required) and coiling for storage, or transport to the HDG customer, Fig 1.

Cold coating weight gauges measure at a maximum temperature of around 60oC and are necessarily installed some distance from the zinc pot, at a point at which the strip has cooled and strip behaviour and temperature is relatively stable (see Fig 1). Such systems are typically scanning cross profile gauges, measuring across the strip width to verify edge-to-edge uniformity. This is valuable information for control of the air knife.

* Senior field marketing manager, Thermo Fisher Scientific September 2021

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COATING

• where product quality specifications are especially demanding.

The case for installing hot coating weight gauges, closer to the zinc pot, is increasingly compelling.

Exposing a coated steel strip to a primary beam of sufficiently energetic photon radiation (typically x-rays) stimulates excitation of the iron atoms and the associated emission of fluorescence radiation with an energy of 6.4 keV; zinc atoms similarly fluoresce with an energy of 8.6 keV (see above Fig – left). As coating thickness increases, the iron fluorescence signal is progressively attenuated, in other words, less radiation emitted by the iron passes through the coating, while at the same time the signal associated with zinc increases (see above Fig – right). By calibrating measurements made with an online x-ray fluorescence sensor against W-S-W data it is, therefore, possible to determine coating weight.

This technology has been successfully used on HDG lines for more than 40 years and is equally applicable for both hot and cold measurement, provided that the process interface is engineered appropriately.

However, the time lag associated with cold measurement is problematic. A cold coating weight gauge is typically ~120m from the air knife giving a dead time of 72 seconds for a line operating at 100 m/min. During this time there is no information on which to base control action. The associated potential to produce out-of-specification material, following a product changeover, can add up to 40,000 m of scrap coil over the course of a year, for a line making just a single specification change each day.

Cold online coating weight measurement is undoubtedly a major step forward relative

to relying on lab-based analysis for process control. Indeed, most producers now only use lab-generated data for quality control checks, since they have the advantage of direct traceability to certified international labs, and for the calibration of online gauges.

However, cold coating weight gauges alone are gradually becoming insufficient to remaining competitive, particularly: • when zinc prices are high • for producers facing the additional complexity of coating with a range of different alloys • as line speeds increase

An introduction to x-ray fluorescence ASTM A754/A754M-215 provides a ‘Standard Test Method for Coating Weight (Mass) or Metallic Coatings on Steel by X-ray Fluorescence’ and was developed specifically for in-process measurement.

It is suitable for both zinc and zinc alloy coatings.

Implementing hot coating weight measurement The sensor head for a hot coating weight measurement gauge incorporates a stable x-ray source, a safety shutter, filtered ion chambers (to measure the intensity of the fluorescent radiation) and the electronics needed to support operation. Such sensors are installed just 2m behind the air knife and, therefore, require appropriate shielding from vibration and temperature.

This positioning cuts the dead time before measurement from over a minute, the lag associated with cold measurement, to just one second. In effect, measurement becomes real-time affording considerable opportunity to improve process control.

Fig 2 Engineering the process interface to deliver the reliability required for 24/7 operation in this harsh environment is vital. Proven solutions, as exemplified by

Coated strip

Hot gauges

Air knife machinery Correction roll Zinc pot Pot roll

Fig 2. Schematic showing a typical arrangement of hot coating weight gauges directly

Fig 3. An online hot coating weight gauge with at line display of top and bottom

above the zinc pot, ~ 2m from the air knife

side coating weight

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COATING

Fig 4. Contrasting a specification change with control based on cold coating weight

Fig 5. An HDG line under more precise coating control (yellow line) delivers lower

measurement (top) and with the addition of hot coating weight measurement

product variation than one under poor control (red line) and can be operated closer to

(bottom)

lower tolerance limits to deliver material savings (green line)

the Thermo Scientific™ RM310 EH Hot Coating Weight Gauge, incorporate a range of features to maintain and safeguard performance such as: • a distance sensor – to measure the distance between the measurement head and the strip, and enable software-driven, automatic compensation for high-frequency distance variations resulting from strip flutter.

• temperature sensors – to measure and compensate for temperature variations in the air gap between the measurement head and the strip and to detect and safeguard against over-temperature in the measurement head; automatic retraction protects the measurement head in the event of a problem.

• flexible detector arm mounting – to allow online measurement or offline coated sample and capability checking.

Beyond routine, reliable operation, features that facilitate system installation and maintenance can also be valuable, particularly when it comes to upgrading existing lines. Installation and maintenance platforms can make a substantial contribution with respect to speed of implementation as can installation directly on the head of the air knife, which is an option with some systems. With a modern, well-engineered system, installation involves minimal downtime, making an upgrade easily accessible as part of a planned shutdown; ongoing maintenance is similarly September 2021

Coating Thermo.indd 3

undemanding.

Optimal process control for HDG lines.

Maximizing the benefit of any online measurement relies on optimizing use of the resulting data. Manual operation remains common for many HDG lines and will undoubtedly improve with the implementation of hot coating weight measurement; however, it is automated control that most effectively exploits the full potential of the technology.

For HDG lines under manual control, hot coating weight gauges provide instantaneous feedback on the effect of a process adjustment. This information is particularly useful as the operator takes the line through periods of transition such as significant changes to air knife conditions or to meet a new product specification. ‘At line’ digital displays provide the information required at the point of process interaction (see Fig 3).

For automated HDG lines, hot coating weight gauges bring more responsive control and the ability to respond rapidly to routine issues such as off-centre displacement of the strip, between the air knives, and changes in surface roughness.

Rather than measuring across the strip, hot coating weight gauges measure at a single point, the centre point of the strip, augmenting rather than displacing the information provided by cold coating weight gauges. Automated control systems are structured to reflect the complementary

nature of the two, meshing data from both to optimize operation. Cascade control is highly effective with the cold coating weight gauges in the ‘master’ role, feeding reference input values to guide setpoint setting for the hot coating weight gauges, which drive fast, primary control cycles.

Using standard control engineering techniques producers can use hot coating weight gauges to enhance their ability to implement model-based predictive control and target optimization control, focusing on the target of minimizing zinc consumption. It becomes feasible to rapidly switch conditions to optimize operation for each new coil and specification, cutting changeover times to minimize waste and maximize throughput. Such control can be implemented in-house working with an established control system, but there are also opportunities to purchase sophisticated control platforms that efficiently integrate hot and cold coating weight gauges and dovetail directly with commercial air knife PLC architecture.

Reaping the benefits of hot coating weight measurement Justifying an investment in hot coating weight gauges calls for rigorous evaluation of the potential savings, to estimate return on investment and/or payback time. Fig 4 contrasts automated operation in the presence and absence of hot coating weight gauges and is helpful in elucidating the benefits. www.steeltimesint.com

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COATING

Data used for the Diagram Production of coated steel per year

400,000 t/

year

Fig 6. Annual savings from the implementation of hot coating weight measurement are con-

Average strip thickness

120 g/m²

Zinc price

3000 $/t

Distance cold gauge to air knife

siderable, even for HDG lines

Distance hot gauge to air knife

operating under automated

Average strip speed

control with online cold coating weight measurement

1.2 mm

Average coating weight per side

160 m 2.0 m 100.0 m/

min Coating variation CV0 without measurement

10.0 %

Coating variation CV2 with manual setting

4.0 %

Average setting time TA of air pressure at air knife 0.12 min

The appreciable dead time associated with cold coating weight measurement, means that it is some considerable time after a setpoint change before the control system begins to make informed corrections to establish a new steady state (see Fig 4 – top). During this period, the HDG line moves to the new setpoint using stored parameter values, but variability is considerable. After the first correction, the line fluctuates within narrower limits as more effective control establishes.

There are two important changes when hot coating weight measurement is added (see Fig 4 – bottom). Firstly, the first informed correction is made much earlier, because data comes through more quickly.

The line, therefore, moves more swiftly to steady state. However, once that steady state is reached, the limits within which the line operates are now far narrower. Any fluctuation is detected more quickly and compensated for more responsively. The line is working within a much tighter tolerance.

Fig 5 illustrates the potential benefit of this more precise control.

If an HDG line exhibits wide product variation due to manual or poor automated control (Fig 5 - red line) then it is essential to have a set point some way from the lower tolerance limit. This allows for variability, without breaking the tolerance limit. The penalties for breaking this limit are poor quality or waste/scrap while the penalty associated with operating away from it is lower profitability, a lesser though still critical problem that is often less immediately visible.

Reducing product variability by implementing or improving control (Fig 5 – yellow line) removes the need to operate so far away from the tolerance limit and the set point can be pushed closer towards it (Fig 5 – green line). This is moving www.steeltimesint.com

Coating Thermo.indd 4

operation closer to the goal of applying just enough zinc to meet the specification, and no more and can result in substantial material savings.

In summary, the better control delivered by the addition of hot coating weight gauges delivers benefit in two important ways: • By reducing product transition times – the HDG line moves more rapidly to a new steady state following a change of specification.

• By reducing product variability – enabling the minimization of zinc coating weight within the constraint of meeting a defined specification.

Fig 6 shows how these benefits translate into annual savings in terms of zinc consumption; absolute figures are dependent on both the condition of the line and the number of product changeovers per day. Details of the figures underpinning the calculation are shown. These figures are relatively conservative and would increase further with the inclusion of savings from reduced waste and higher throughput.

However, they are significant and explain why an investment in hot coating weight gauges is typically associated with a relatively short payback time, in the region of just six months even when plants are already operating automated control. This is the impact of the greater responsiveness that hot measurement provides, relatively to cold.

Looking ahead Hot coating weight gauges have now been in use for more than 20 years, ample time to demonstrate industrial reliability standards and economic potential. An investment in online analysis is necessarily made on the basis of deliverable savings

and there is now a body of evidence showing what these are.

Hot coating weight gauges measure just a few metres from the zinc pot providing data in a fraction of the time associated with cold measurement. These data can be used to drive more responsive control that cuts the time taken to transition from one product specification to another and to push operation closer to the goal of minimal zinc consumption. In this way, hot coating weight gauges boost the performance already achieved with online cold measurements delivering much tighter, more precise control. For an industry facing higher zinc prices, faster processing rates and increasingly stringent demands on quality, this improved control ensures a payback time that comfortably justifies investment. �

References 1 Zinc price data. Trading Economics.

Available to view at: https:// tradingeconomics.com/commodity/zinc 2 ‘Global zinc demand to outpace production in 2021narrowing surplus: UGMK’ News Item. Available to view at: https://www.spglobal.com/platts/en/marketinsights/latest-news/metals/031021-globalzinc-demand-to-outpace-productiongrowth-in-2021-narrowing-surplus-ugmk 3 A 90/A 90M Test Method for Weight (Mass) of Coating on Iron and Steel Articles with Zinc or Zinc-Alloy Coatings 4 ISO1460 Metallic Coatings – Hot Dip Galvanized Coatings on Ferrous Materials – Gravimetric Determination of the Mass per Unit Area 5 ASTM A754/A754M-21 Standard Test Method for Coating Weight (Mass) or Metallic Coatings on Steel by X-ray Fluorescence September 2021

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PERSPECTIVES Q&A: ADVANCED ACTUATORS

No compromise on quality Advanced Actuators’ order book is continuing to grow as the world emerges from the effects of the global pandemic. The company has just announced that it is joining forces with Ashton Bulk to offer customers a total solution combining industry design expertise and established manufacturing skills.

Advanced Actuators’ MD, Chris Woodhead* answers this month’s questions Even though aluminium is lighter, which for offshore applications has a benefit as a number of our components are fabrications, there is a lack of qualified companies local to us that have the qualification to weld aluminium. The level of preparation is different to welding steel of which there is a greater number of qualified steel welders.

1. How are things going at ADVANCED ACTUATORS? Is the steel industry keeping you busy?

We’re experiencing a welcome increase across customers in all sectors and the order book is continuing to grow as we emerge from the effects of the pandemic.

However, there still seems to be a delay in the commitment to placing orders from the steel industry. We believe part of the issue is that key players are still working from home and this is creating delays in getting signatures on orders, but we’re optimistic that this delay will ease as people return to the workplace.

2. What is your view on the current state of the global steel industry?

Steel is an essential component for our business of manufacturing hydraulic actuators and we buy steel in many forms necessary to build into our machines and continue business. In the last 12 months, we have seen a definite increase in delivery times and prices are rising which has had a huge impact on our company. We have to be strategic in ordering to minimise any delays in completing orders and while we always resist passing on price increases to customers we’re hoping to see costs settle down soon to prevent prices being pushed up.

3. In which sector of the steel industry does ADVANCED ACTUATORS mostly conduct its business?

Many of our products are used in the steel industry, from the extraction and handling of iron ore to playing a major role in the manufacturing of steel. We have recently completed contracts in Guinea and South Africa on two train-unloading facilities for iron ore where our system unloads a 40-tonne wagon every 90 seconds.

4. Where in the world are you busiest at present?

We’re currently seeing our greatest numbers coming from South Africa and India. We cannot say for definite why this is, but there appears to be a need for new handling plant.

5. Can you discuss any major steel contracts you are currently working on?

We are working on several opportunities both in the UK, Eastern Europe and India, which are in the early stages and we’ll be revealing more when we’re able to share more details.

6. Where does ADVANCED ACTUATORS stand on the aluminium versus steel argument?

Due to the nature of our products we use little aluminium. We use SG iron, carbon steel and various types of stainless steel.

7. Hydrogen steelmaking appears to be the next big thing. What’s your view? Our products are used on bulk materials handling systems so the increased use of hydrogen would reduce our order book as the use of coal/coke will be eliminated. However, we fully agree we must minimise our levels of pollution, and hydrogen could be part of this reduction, but we understand, blue hydrogen is made from coal or natural gas which, to a certain extent, defeats the object of increased hydrogen use.

8. In your dealings with steel producers, are you finding that they are looking to companies like ADVANCED ACTUATORS to offer them solutions in terms of energy efficiency and sustainability? If so, what can you offer them?

We are always looking at ways we can improve our products for customers in all sectors, as this is the only way to stay ahead of the competition and address the needs of our customers in an everchanging world, constantly hit by changes in legislation, challenges in supply and environmental concerns. One of the key areas we have concentrated innovations in recent years is to reduce the energy consumption of our machines and making sure we use as much recyclable product as possible in their make-up. We also spend

* Managing director, Advanced Actuators September 2021

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PERSPECTIVES Q&A: ADVANCED ACTUATORS

a lot of resources on developing better controls to reduce downtime, which can be financially crippling to industry.

9.

How quickly has the steel industry responded to ‘green politics’ in terms of making the production process more environmentally friendly and are they succeeding or fighting a losing battle?

Twenty years ago, processes were put in place in the manufacture of coke for steel, aimed at reducing environmental pollution, which are still in practice today. While there is inevitably some level of pollution produced in the production of steel, processes to combat the environmental effects have been a consideration in the industry for more than two decades.

10. Where does ADVANCED ACTUATORS lead the field in terms of steel production technology?

We specialise in hydraulic actuators, hydraulic systems and full electrical controls of our product including writing software.

Though unrelated directly to the steel industry, we have recently completed contracts for the UK Ministry of Defence on a number of specialist test rigs and a gate control system for Thames Water, London.

Both contracts included a significant amount of steel and stainless fabrications and components.

11. How do you view ADVANCED ACTUATORS’ development over the short-to-medium term in relation to the global steel industry?

We will be concentrating on the integration of hardware and software. Manufacturers of today need an equal understanding of both parts. At Advanced Actuators, we have found that by developing our expertise in software as well as manufacturing we have been able to reduce energy costs and plant downtime for our customers.

12. What is ADVANCED ACTUATORS’ experience of the Chinese steel industry?

Unfortunately, our key markets are driven by price and thus we presume our suppliers have to look for the best prices, which may mean sourcing supplies from other countries such as China. However, we would never compromise on quality to save on cost as this would do our reputation more harm than good. But, as long as the quality is high we will continue to consider procuring from China where necessary.

13. Where do you see most innovation in terms of production technologies – primary, secondary or more downstream?

In all sectors. All want to improve what they do now by better monitoring or being more environmentally friendly.

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14. What exhibitions and conferences will ADVANCED ACTUATORS be attending over the next six months?

Our plans to attend events have been greatly scaled down due to the uncertainty relating to COVID-19, but we hope to return to attending exhibitions and conferences very soon.

15. ADVANCED ACTUATORS is headquartered in the UK, but what’s happening steel-wise in the country?

There are some big development projects underway at some plants but they appear to be taking time to be fully rolled out.

16. Apart from strong coffee, what keeps you awake at night?

Our biggest sleep depriving issue is development of our products and particularly how we can use software to give better control, better monitoring and a reduction in downtime.

17. If you possessed a superpower, how would you use it to improve the global steel industry?

Give people more time to think about how we can develop our products. �

If you would like to be the subject of our regular Perspectives Q&A feature, email: matthewmoggridge@quartzltd.com

An Ashton Bulk-designed stacker/reclaimer

September 2021

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HISTORY

Siemens-Martin open hearth furnaces

Resita – post World War One This is the final article in a series tracing the history of iron and steelmaking in the Romanian town of Resita, which today celebrates 250 years of production, and is presently under the ownership of TMK. The previous article, published in the August digital version of STI, brought the company into the first half of the 19th century, when under the ownership of the Austrian State Railway. Operating Bessemer, Siemens-Martin and electric arc steelmaking, it produced railway track, bridges and rolling stock, including locomotives. By Romulus Ioan* POST WWI the Romanian Government promised to give 50% of all orders to the Resita plant, then still owned by the Austrian State Railway (StEG). In June 1920, the company was nationalised and renamed Resita UDR. As part of the ‘Iron Mills and Domains of Resita’ it encompassed coal mines, iron ore mines, copper and gold mines, as well as the steel works.

Iron and steel plant consisted of two blast furnaces, two coking batteries of 62 ovens each, two Siemens-Martin furnaces of 300t capacity and six of 30t capacity, an electric arc furnace and a foundry. The Bessemer converters had been phased out in 1899, after 31 years in use during which time output reached 30kt/yr. Mills consisted of a profile mill and a sheet mill. Charcoal production was phased out by 1923.

Capital was raised by issues of shares progressively between 1920 and 1937.

During the recession of 1929-33, the State government became heavily involved in supporting the works through orders and loans. From 1930, production of locomotives at Uzinele Resita was sufficient

to meet all domestic demand.

In 1934-5 a new coking plant was built with two 12-chamber Koppers batteries and the old coke plant closed. Coke production increased from 31.725kt in 1934 to 72.625kt in 1944.

Coke production

100

Cast iron production

75

Steel production

80

Rolled product output

70

Build of locomotives

50

Production of railway tyres and wheels

100

Table 1 Share of Resita plant in the economy of Romania

Iron production As well as producing pig iron for the Siemens-Martin furnaces, the blast furnaces produced Spiegel iron (high Mn) for deoxidising and ferro-silicon. Output from the two furnaces increased from 14.074kt in 1920 to a wartime peak of 106.168kt in 1943. In 1940, following the outbreak of WW II in September 1939, Romania fought with the Axis Powers against Russia, but switched to fighting alongside Russia in support of the Allies in August 1944, following a coup of the government.

in 1939 (%)

Steel production Siemens-Martin open-hearth steelmaking increased from 30.882kt in 1920 to 179.822kt in 1944 peaking at 228.289kt in 1943. Electric arc production commenced in 1922 with 331t produced and reached

Rolling mills Modernisation of the mills commenced prior to WWI and consisted of six rolling lines for long and flat products, including an ingot slabbing mill. Further modernisation in 1928-30 increased rolling

4.091kt in 1944, peaking at 6.253kt in 1942. By 1944, there were seven SiemensMartin furnaces of 50t, 60t and 120t capacities, the latter with tilting capability.

Steel types included non-tempered steels, carbon steels, special and alloy steels, the latter including Ni-steels for locomotive axles, crankshafts and gun barrels. Cr-Ni steels were produced for shells and armour plating.

* Dr Ioan is executive director of the modern Resita steelworks, part of the TMK Group September 2021

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HISTORY 56

other heavy items such as roofs and oil and gas tanks from steel provided from the mills. 180 railway bridges and 100 road bridges were built. In 1930, the first all welded bridge in Romania was fabricated at Resita-Stavila. During the war, armaments were produced as well as smaller items for railway rolling stock such as wheels, also winches and rotary cranes. Factories were established to produce agricultural machinery and electric motors and dynamos.

capacity from 160kt/yr in 1930-33 to 210kt in 1940.

Forge Between 1929 and 1931, two ‘Brett’ free falling hammers were installed and in 1937 a Weidmann reheating furnace. Two oilfired and two electric annealing furnaces were commissioned during WWII to meet wartime demand. Both forged and pressed parts were produced, output reaching 5435 tonnes and 6936 tonnes respectively by 1944.

Foundry and repair shop In 1937, the foundry was expanded with 14 small crucible furnaces and one large crucible furnace. Combined capacity reached 18kt/yr.

The mechanical repair shop was equipped with shaping machines, three drilling machines, 10 lathes, three punches, a milling machine, a thread cutter and a hammer and forge.

Bridge building A separate factory constructed bridges and

Prominent position Between the two wars, Resita dominated iron and steel production in Romania and also played a key role in heavy manufacturing. Table 1 illustrates this.

Today, TMK Resita is a modern electric arc furnace plant with a capacity of 450kt/ yr. Its main products are seamless pipe of diameters 122, 250, 280 and 350mm and continuously cast bloom 270x340mm. Steel grades range from carbon steels, medium alloy, alloy steels and re-sulphurised freemachining steel, all of which can be treated by vacuum degassing. �

Dr Ioan is author of the book 250 years of steel in the Resita Plant 17712021.

Written in the Romanian language, the 355 pages of text are followed by extensive summaries in English and Russian. Multiple tables of production and costs are scattered throughout the book. Copies are available from the author who can be reached at the following email address: romulus.ioan@tmk-artrom.eu

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