PHILIPPINE SOCIETY OF MECHANICAL ENGINEERS WESTERN REGION SAUDI ARABIA – JEDDAH CHAPTER Kingdom of Saudi Arabia Web: www.psme-wrsa.org Email: psmewrsainbox@gmail.com
“MOST OUTSTANDING CHAPTER, YEARS 2005, 2006, 2007 & 2011”
BOARD OF DIRECTORS
NAPOLEON M. CEPRIASO, PME President
MAURICIO T. VIADO JR., ME Vice President
EDGAR B. TONGSON, ME Secretary
JAIME L. LEVISTE, ME Treasurer
RAUL I. SIENES, ME Auditor
JOSEPH MAR ADRIAS, ME PRO
RODRIGO C. LOFAMIA, ME Membership Director
DANIEL A. MAGAYANO, PME Technical Affairs Director
ROEL ALFON G. BANAWIS, ME Plant Tours Director
Resource Speaker:
ACE GLEN B. GARCIA, ME External Affairs Director
Mr. WAYNE WINGLE
JEFFREY C. ESPERANZA, ME Internal Affairs Director
JULIUS Q. GARCIA, ME Professional Enhancement Director
CRISOSTOMO C. ORTIZ, ME Sports Director
LEE I. BONIFACIO, ME Code of Ethics
April 20, 2012
JOEL A. SANTOS, ME Information Technology Director
ENRICO I. DELGADO, ME Yanbu/Rabigh APU Coordinator
New Al Jedaani Hospital Lecture Room Jeddah, Saudi Arabia
THEME: " Mechanical Engineering Towards Economic Priorities in Renewable and Sustainable Energy"
***PAST PRESIDENTS***
*2011 – Rainier P. Patawi, ME * 2010 - Joselito B. Bentulan, PME * 2009 - Julio D. Caringal, PME * 2008 - Froilan G. Miro, PME * 2007 Joselito A. Arellano, PME * 2006 - Willie C. Leoncio, PME * 2005 - Ernesto C. Cala, PME * 2004 - WIlfredo R. Ruiz, PME * 2003 - Orlando L. Digma, PME * 2002 - Juan U. Berbie, PME * 2001 - Dionisio A. Lora Jr., PME * 2000 - Wilfredo R. Ruiz, PME * 1999 - Filemon E. Agulo, PME * 1998 - Danilo V. Gercio, PME * 1997 - Rene C. Bernales, PME * 1996 * Rene Y. Logarta, ME * 1995- Ruben N. Parpan, ME * Nildo K. Tan Jr., PME - 1994 Charter President
Non-Destructive Testing and Welding Process Applications PREPARED FOR THE PHILIPINO SOCIETY OF MECHANICAL ENGINEERS CONTINUED EDUCATION LECTURE SERIES JEDDAH, KINGDOM OF SAUDI ARABIA LECTURE BY MR.WAYNE WINGLE, LIVERPOOL, ENGLAND.
CONTENTS • Introduction to the Welding Processes • Welding Design Knowledge • Welding Codes • Weld Imperfections and their causes • Visual Inspection • Dye Penetrant Inspection • Radiographic Inspection • Magnetic Particle Inspection • Dye Penetrant Inspection • Ultrasonic Inspection
Introduction to the Welding Processes
Most welding processes are commonly referred to as Arc welding welding, but can be clearly separated and “Arc� categorised now. The four most common welding processes p ocesses that t at people peop e cou could d be familiar a a with t aare: e: y SMAW SMAW- Shielded Metal Arc Welding y GMAW- Gas Metal Arc Welding y FCAW- Flux-cored Arc Welding y GTAW- Gas Tungsten Arc Welding
SMAW The American Welding Society defines SMAW as Shielded Metal Arc Welding
y SMAW: { Is commonly known as ‘Stick’ welding or manuall arc welding ldi { Is the most widely used arc welding process in the world { Can be used to weld most common metals and alloys
SMAW Process L t’ take Let’s t k a little littl closer l llook k att th the SMAW process… Electrode
1
Travel direction
4 6 6
Shielding Gas
Slag Slag Weld Puddle 3 Weld Puddle
3 5 5
2 2
Arc Arc
Solidified Weld Metal Solidified Weld Metal
5
1- The Electrode y Is a consumable - it gets g
melted during the welding process y Is composed of two parts {
Core Rod (Metal Filler)
{
Carries welding current Becomes part of the weld
Fl Coating Flux C ti
Produces a shielding gas Can provide additional filler Forms a slag
6
2- The Arc 2 y An arc occurs when the
electrode l t d comes iin contact with the workpiece and completes the circuit i i ‌ lik like turning i on a light! y The electric arc is established in the space between the end of the electrode and the work y The arc reaches temperatures of 10,000°F which hi h melts l the electrode and base material 7
3- Weld Puddle y As the core rod,, flux
coating, and work pieces heat up and melt, l they h fform a pool of molten material called a weld puddle y The weld puddle is what a welder watches and manipulates while welding
1/8� E6013 at 125 Amps AC
8
4- Shielding Gas y A shielding hi ldi gas iis
Shielding Gas 4
3 2
The shielding gas protects the molten puddle from the atmosphere while stabilizing the arc
formed when the flux coating ti melts. lt y This protects the weld puddle from the atmosphere preventing contamination d during the h molten l state 9
Advantages g of SMAW y Low initial cost y Portable y Easy to use outdoors y All position capabilities y Easy E to t change h b between t
many base materials
10
Limitations of SMAW y Lower consumable
efficiency y Difficult to weld very thin materials y Frequent restarts y Lower operating factor y Higher operator skill required for SMAW than some other processes 11
GMAW- Gas Metal Arc Welding g
GMAW (MIG/MAG)
What is GMAW? GMAW = Gas Metal Arc Welding y MIG/MAG Welding { {
MIG = Metal Inert Gas MAG= Metal Active Gas
y Requires a CV and/or
CC Power P S Source y Solid Wire with External Shi ldi G Shielding Gas y DCEP (DC+) Polarity
Gas Metal Arc Welding An arc welding gp process that uses an arc between a continuous filler metal electrode and the weld pool to produce d a ffusion i ((melting) lti ) ttogether th Of the base metal. The process is used with a shielding gas (or gas mixture) from an externally supplied source and without the application of pressure.
Advantages g y Variety of Metals y Various V i Thickness Thi k off
Materials
y High Efficiency
Applications
y High Radiated Heat
Advantages g continued y All Position Welding y Quality Welds y Little to No Slag y Low Spatter
Limitations
y Cost y Portability y Outdoor Welding y Clean Base Material
Limitations continued
y Potential for Cold Lap y Potential for Undercut y Operator Skill y High Radiated Heat
FLUX CORED ARC WELDING FCAW C - SS Innershield速 FCAW - GS Outershield速
What is FCAW-SS? FCAW SS = Flux Cored Arc FCAW-SS Welding-Self Shielded y Innershield速 Welding y Process Developed by Lincoln Electric y Tubular T b l Wire Wi with ith Fluxing Fl i Agents Inside the Core to Protect the Weld y Most Electrodes Operate DCEN (DC-) polarity, some on DCEP (DC+)
FCAW-SS A flux cored arc welding process variation that uses an arc between a continuous filler metal electrode and the weld pool in which shielding is obtained exclusively from the flux within the electrode and without ith t th the application li ti of pressure.
Advantages y Outdoor Usability b y y Minimize Restarts y No Shielding h ld Gas Costs y High Deposition Rates
Advantages continued y Mechanical Properties p y Effective Smoke
Removal y Dirty Steels y All Position Welding g
Limitations y Smoke and Fumes y Spatter y Slag l ((Cleaning l Time)) y Break Electrode to
Restrike
What is FCAW-GS? FCAW-GS = Flux Cored Arc Welding-Gas Shielded y Outershield® Welding & “Double Shield” Welding y Tubular Wire With Fluxing Agents Inside the Core y Used With An External Shielding Gas y All Electrodes El d O Operate on DCEP (DC+) Polarity
FCAW-GS A flux cored arc welding process variation that uses an arc between a continuous fill metal filler t l electrode l t d and the weld pool in which shielding hi ldi gas is i supplied li d through the gas nozzle without the application of pressure, in addition to that obtained from the flux within the electrode.
Advantages y Bead Appearance pp y Little to No Spatter y High h Deposition Rates y Mechanical Properties
Advantages g continued y High g Efficiencies
(90+%) y Easy Re-strike y All Position Welding y Low Hydrogen y g Weld
Deposits
Limitations y Smoke and Fumes y Portability y Outdoor Weldability y Potential for Gas
Marks y High Radiated Heat y Slag
GAS TUNGSTEN ARC WELDING
GTAW (TIG)
What is GTAW? GTAW = Gas Tungsten Arc Welding y “TIG” W Welding ldi y Requires a Constant Current Power Source y Non-Consumable Tungsten Electrode y Requires an External Shielding Gas
What is GTAW? y A Filler Rod May y or Mayy Not Be
Necessary y AC Polarity y for Aluminum & Magnesium g y DC- Polarity for Most Other Materials y DC+ Rarely if Ever Used
Gas Tungsten g Arc Welding g An arc welding process that uses an arc between a tungsten electrode (non-consumable) and the weld pool. l The process is used with shielding gas ((or g gas mixture)) from an externally supplied source and without the application off pressure.
Advantages g y High Quality Welds y All Position Welding y Can Be Used on a
Variety of Metals y Excellent on Very y
Thin Materials
Advantages continued
y Fusion (Autogenous)
Welding is Possible y No N Sl Slag y No Spatter y High Efficiency
Limitations continued
y Low Deposition Rates y High h Operator Skill k ll
Necessary y Often Slow
Welding Design E Exceptional ti lW Welding-design ldi d i is i in i ffactt th the precondition diti f outstanding for t t di weldments. Important p as it mayy be,, this is not always y self-evident. Because of their standard p preparation, p , Designers and Engineers, however expert in their profession, may lack involvement in certain aspects of welding technology, essential to successful welding design. Why is Good Design so important? Because, being the required knowledge so vast, it is quite possible for professionals, exposed only occasionally to welding as one of many other fabrication technologies, to neglect inadvertently fundamental details too specialized to be of common knowledge. Thi iin turn may cause more costly This l welding ldi operations, i or diffi difficulties l i iin obtaining b i i d defect f ffree weldments, or even welding failures that could have been prevented. In the Conclusion at the end of Chapter 5 - Design for Welding - of the American Welding Society (AWS) Welding Handbook, Ninth Edition, Volume 1, at page 236 one reads: "Many issues are related to the process of designing for welding. In addition to component performance, service, intended life and safety, the designer should have a good understanding of the fundamentals of welding, metallurgy, fabrication technology and inspection techniques . techniques".
Welding g Design g y In the introduction to the above Chapter the authors list fifteen items of
specialized knowledge whose effects on Welding-design should always be evaluated, and they add that designers should "refrain to rely only on their own k knowledge l d and d experience" i "b but should h ld b be ""encouraged d to consult l with i h welding ldi experts wherever appropriate". y This condition, when coming from welding professionals, risks usually of them being be g dismissed d s ssed as "self se serving", se v g , by co confident de t des designers g e s who w ob brag, ag, to themselves and to their management, that they don't need any additional welding advice. y It seems to be increasingly accepted the modern trend indicating a growing need in Welding Welding-design design team activity activity, to satisfy requirements covering different disciplines that cannot possibly be mastered by a single individual. At a minimum, the chief designer should make sure to submit new design to professionals with welding experience for their review of welding issues. y A short h page on W Welding-design ldi d i lik like this hi one can only l alert l receptive i and d curious professionals to the large mass of specialized knowledge available, that should be tapped in every instance of involvement with any project calling g and encourage g them to check the issues in depth, p either alone or for welding, with h the h h help l off experts off the h matter.
Welding g Design g Individuals responsible for Welding-design Welding design should dedicate time and study to learn and assimilate at least the basic principles of the different subjects intervening in establishing effective weldments, in order to be receptive to the input available from welding specialists. Converselyy welding g experts p should familiarize themselves with Welding-design g g to the point of understanding construction and manufacturing requirements even if it is not their piece of cake, and developing an effective communication language to make their points clear without generating resistance or hostility. The Role of Experience There is no substitute for experience. Welding-design should be based on knowledge of the principles, refined by experience, distilled in quality examples of successful, cost effective realizations. W ldi d i Welding-design, as well ll as any other h engineering i i d design i not iinvolving l i welding, ldi starts as an approximate idea or sketch of what is needed, with estimated applied and service loads, once a general idea is conceived about the form and functionality of the new construction. Th t will That ill provide id a provisional i i l approach h as to t which hi h elements l t mustt b be used d and d off their tentative dimensioning. The design process must undergo successive alterations and refinement, that permit to determine with increasing precision the loads acting on single members.
Welding g Design g y Stability is traditionally assured by calculation of the applied loads or forces, those
y y y y y
deriving from the weight of the structure itself and from environmental conditions (wind, snow etc.), and those produced by the performance of the intended functions (i.e. hoisting, moving materials or whatever action is done). Loads and a provisional selection of shape and dimensions for force sustaining members define stresses and strains operating on the structural elements and on the joints. The largest Stresses to be sustained by the structure allow to select tentatively the materials to be employed employed, based on tables of mechanical properties properties. At some point one has to check the service conditions (normal and extreme temperatures, exposure to atmospheric or corrosive media) and to verify if the provisional selection is adequate. Th final The fi l selection l i iis most off times i a compromise i solution, l i as usuall ffor many other engineering decisions, acceptable in terms of functionality, economy and building time. It is the designer's g responsibility p y to verifyy that working g stresses are well within acceptable bl li limits i for f safe f operation. In d definite f cases the h Welding-design ld d off certain structures must, by law, meet Code Requirements
Welding g Design g y
Properties p s of Materials s It should be remembered that material properties include both those insensitive and those sensitive to metallurgical structure. To the first group pertain physical properties like thermal expansion and conductivity, melting point (or range), p g specific p heat and emissivity, y density, y Vapor p p pressure and electrical conductivity. One should remark that the Modulus of Elasticity, valid only in the elastic range, is structure insensitive but temperature dependent, while the Elastic Limit, delimiting the elastic behavior and the start of plastic deformation, is structure sensitive. T the To th second d group pertain t i mechanical h i l properties ti like lik Yield Yi ld and d Ulti Ultimate t St Strength, th h hardness, d ductility and elastic limit, Toughness, Fatigue Strength, Creep and Rupture Strength. As affected by microstructure, these are the properties most likely to be modified by welding processes, usually (not always) performed by applying considerable amounts of heat. Therefore the properties of as welded metals may be strikingly different from those of the base metal before welding application. Furthermore one should be alert to factors that, without being properties, affect mightily the suitability of weldments to perform safely for their service life: among these are notch effects, multi-axial and residual stresses,, surface finishes and special p coatings. g If welding is needed for fabrication, weldability of proposed materials must be verified. It should be understood that properties and characteristics of materials are influenced and changed by welding processes, and therefore at the Welding-design stage one must specify the required processes while taking into account their consequences on integrity and stability
Welding g Design g y Metallurgy and weldability are essential considerations for Welding-design, Welding design,
y y y
y
especially when it appears that special procedures have to be implemented for successful welding. In certain cases suitable controls should be specified in drawings and implemented during welding to avoid brittle fracture. The requirements may well be established in detail by experts, experts but the designer is responsible for specifying their adoption on the drawing or other binding document. The Mechanical properties to consider are those displayed at actual service temperature. temperature When considering Welding-design involving the use of aluminum alloys, it is important to remember that the strongest alloys are not weldable by regular fusion processes, as explained on the Materials page, and that only specific processes can be used to preserve those high properties (like strength and corrosion resistance), as explained in a page on Aluminum Welding. Material selection should follow a complex procedure which has to consider, besides standard mechanical properties and manufacturing constraints, also requirements i t for f resistance i t tto corrosion i or weathering th i agents, t need d ffor protection, t ti finishing and ease of maintenance, as well as availability and economy of production.
Welding g Design g y Special design instructions may be needed, needed like minimum
ambient temperature required for load testing of structures whose toughness may be affected by very cold conditions. Fracture g is a veryy important p p property p y to be studied thoroughly g y toughness because it is likely to depend on ambiental conditions (temperature), load application (rate and directionality) and presence of notch (stress concentrating feature). y Projected j d savings i iin maintenance i along l the h planned l d lif life off the h structure may suggest the selection of a more resistant material even if more expensive at purchase time. This concept is sometimes called the Total Life cost. cost y Similarly, if weight is at premium (for high rise constructions or for transport), higher properties may permit weight reduction and savings even if more expensive materials are selected. savings, selected It is not uncommon to examine different designs to find out maximum advantages at minimum costs or compromize solutions.
Welding g Design g For Welding-design Welding design the following Factors should be considered: y Review of Experience with existing products and eventual modifications y Review of prevailing load conditions, to provide for fatigue resistance if required, for y y y y
y y y y
the h d design i service i lif life Review of interaction with other members or service media Review of Metallurgy and weldability of proposed materials Weld joint design geometry, geometry dimensioning and preparation that takes into account the welding process to be used Tolerances on Size of welds Note: - If mechanized and robotic fabrication is considered, Welding-design should pay particular attention to set realistic joint tolerances tolerances, especially for sheet metal parts. Subassemblies, provisions for fool proof assembly Availability, y cost Ease of fabrication, manufacturing constraints and economy of production Safety and stiffness without over-designing, resistance to weld distortion
Welding g Design g For Welding-design the following Factors should be considered(contd): y Heat flow,, internal constraints,, residual stresses y Accessibility for manufacturing and ease of maintenance y Closed sections for torque resistance, esthetic requirements, use of standard y y y y y y y
sections Inclusion l i off welding ldi aids id lik like attachments h ffor h hoisting, i i h handling, dli overturning i Accessibility for inspection, provisions for use of positioners Welding procedures W ld Map Weld M establishing t bli hi placement l t and d sequence off welds ld Need of preheating and post weld heat treatment Inspections requirements Cleaning needs of protection and Finishing Cleaning,
Welding g Design g y Unacceptable defects are those compromising stability and/or functionality. They
y
y y y
should be established by design, specifying limits for acceptable discontinuities, detected by visual and other non destructive inspection methods, each technique with its requirements. q When using radiography (X-Ray inspection), reference is usually made to the volumes of Reference Radiographs (see in Welding Inspection), according to materials and thickness: the designer has to select the maximum size and density of defects that is acceptable p for the service conditions of the item on hand,, and establish on the drawing a note to this effect. If resistance to fatigue straining is an issue, then the assessment of the relative fatigue life of welds should be researched and, if applicable, fatigue life improvement (i.e. shot peening) methods should be implemented. Drawings of weldments should use the standard Symbols that express completely the essential features and requirements of welded joints. ANSI/AWS A2.4:2012 Standard Symbols for Welding, Welding Brazing, Brazing Nondestructive Examination American Welding Society / 01-Jan-2012 / 152 pages
Welding g Design g y
y y y y y y y y y y y y
Drawing g Notes s As a consequence of the final configuration of the design adopted, definite instructions representing essential information must be included in welding drawings. This is done by adding suitable notes to the drawings, as listed hereafter. The notes assure the transmission to the fabrication personnel of the practical ways to be employed for realizing the designer's i t ti intentions. Material and condition as per Specification, Joint design and dimensions as described by the use of standard symbols, welding process to be selected or authorized alternatives, Joint dimensions, preparation and fixturing, Cleaning procedures, Tolerances for fit-up, Filler material,, size and Specification, p , Minimum and acceptable joint size, (as it can influence quality and cost) Special precautions as Welding Procedure Specification (WPS) if required, Inspection requirements and acceptance limits, Heat Treatment if required, required Code Requirements if applicable like: { { {
WPS (Welding Procedure Specification), PQR (Process Qualification Record) and WPQ (Welder Performance Qualification).
Codes Governing g Welding g A code d iis a sett off requirements i t covering i permissible i ibl materials, service limitations, fabrication, inspection, testing procedures and qualification of welders. welders Welding codes ensure that safe and reliable welded products are produced and that persons associated with the welding procedures are safe. Clients specify in the contract the codes that will be used on a project. All welding must then be carried out according to the guidelines and specifications outlined in that code.
Codes Governing g Welding g
Codes and standards that apply to welding quality and safety have been developed and published by a number of internationally recognised bodies: y American Society of Mechanical Engineers (ASME) y American Welding g Societyy ((AWS)) y American Petroleum Institute (API) y American National Standards Institute (ANSI)
ASME ASME has h ttwo codes: d th the ASME Boiler B il and dP Pressure Vessel Code and ASME B31, Code for Pressure Piping The ASME Boiler and Pressure Vessel Code Piping. contains eleven sections the most commonly referenced by welders are as follows: y Section II, Material Specifications- This section contains t i s the th sspecifications ifi ti s ffor acceptable t bl fferrouss (Part A) and n0n-ferrous (Part B) base metals and for acceptable welding and brazing filler metals and fluxes (Part C)
ASME y Section V,, NDE- This
See Handout 1 for ASME B31 References.
section covers the methods and standards for the non non-destructive destructive examination of boilers and p pressure vessels. y Section IX, Welding and Brazing QualificationsThis hi section i covers the h qualification of brazers and the procedures for welding or brazing boilers.
AWS
The AWS publishes numerous documents covering welding. These documents include codes, standards specifications, standards, specifications recommended practices and guides guides. See Handout 2 for AWS D1.1 Structural Weld Code-Steel R f References.
AWS D1.1,, Structural Welding Code-Steel, is the most frequently referenced It covers referenced. welding and qualification requirements q for welded structures of carbon and low-alloy steels. It is not intended to apply to pressure vessels, pressure p p piping p g or base metals less than � thick.
American Petroleum Institute
The API publishes documents in all areas related to petroleum production. API 1104, Standard for Welding of Pipelines and Related Facilities, applies to the arc and oxy-fuel gas welding of piping, pumping, transmission and distribution systems for petroleum. It presents methods for making acceptable welds b qualified by lifi d welders ld using i approved d welding ldi procedures, d materials and equipment. It also presents suitable methods to ensure proper analysis of weld quality. See Handout 3 for Reference to a “Typical welding procedure document� related to API 1104
Weld Discontinuities and their Causes AWS defines d fi a “di “discontinuity” ti it ” as an iinterruption t ti off th the typical structure of a weldment, such as lack of homogeneity in the mechanical mechanical, metallurgical or physical characteristics of the material or weldment. A discontinuity is not necessarily a defect defect. A defect found during inspection will require the weld to be rejected A single excessive discontinuity or a rejected. combination of discontinuities can make a weldment defective However a weld can have one or more defective. discontinuities and still be acceptable .
Weld e d Discontinuities sco u es a and d their e Causes Causes: Porosity o os y The most common weld discontinuities are the following: y Porosity y Inclusions y Cracks y Incomplete joint preparation y Incomplete fusion y Undercuts y Arc strikes y Spatter y Unacceptable weld profiles
Porosity Porosity is the presence of voids or empty spots in the weld metal. This occurs as a result of gas pockets being trapped in the weld as it is being made. As the molten metal hardens, the gas pockets form voids. Unless the gas pockets work up to the surface off the h weld ld b before f iit h hardens, d iit cannot be viewed by visual inspection. p
Weld e d Discontinuities sco u es a and d their e Causes Causes: Porosity o os y Porosity can be grouped into the following major types: y Uniformly scattered porosity- May be located through single pass welds or through several passes in multi-run welds y Clustered p porosityy A localised grouping of pores resulting from improper starting and stopping techniques. y Linear Porosity- May be aligned along a weld interface, the root of a weld or a boundaryy between welds. y Piping porosity- Normally extends from the root of the weld towards the face. These elongated g p pores are also called wormholes.
Weld e d Discontinuities sco u es a and d their e Causes Causes: Porosity o os y y Most porosity is caused by
improper welding techniques or contamination. Improper welding techniques may cause i d inadequate t shielding hi ldi gas coverage of the weldment, as a result parts of the weld are left p Oxygen yg in the air,, unprotected. or moisture in the flux or on the base metal that dissolves in the weld pool can become trapped and produce porosity porosity. y The intense heat of the weld can decompose paint, dirt, oil or p g other contaminants, producing hydrogen. This becomes trapped in the molten, but solidifying pool and produces porosity.
Inclusions
Inclusions are foreign matter trapped in the weld metal, as above.
Weld Discontinuities and their Causes: Inclusions Inclusions generally result from faulty welding techniques, improper access to the joint or both. A very common example is slag, the protective cover which normally is p over a completed p deposited weld. Incorrect manipulation of the welding electrode results in slag g being g blown in to the weld pool. With proper welding techniques and ideal parameters for welding, p g, most inclusions can be avoided or kept to a minimum.
Other remedies include the following: y Position the work to maintain slag control y Change the electrode to improve molten slag control y Thoroughly Th hl remove slag l during weld passes y Grind the weld surface if it is rough and likely to trap slag y Remove heavy millscale on all materials y Avoid the use of electrodes with damaged coverings
Weld e d Discontinuities sco u es a and d their e Causes Causes: C Cracks ac s Three b Th basic i types t off cracks can occur in weld metal: transverse, transverse longitudinal and crater. As seen in the sketch the cracks are named to correspond with their di ti and direction d llocation ti
Weld e d Discontinuities sco u es a and d their e Causes Causes: C Cracks ac s y
Transverse cracks run across the face of the weld or may extend into the base metal. They are very common in joints that have a high degree of restraint.
y
Longitudinal L it di l cracks k are usually ll located in the centre of the weld deposit. They may be the continuation of crater cracks or cracks in the first layer of welding. welding Cracking in the first pass or root run is likely to+ y occur if the deposition is too thin. Removal of the crack at this stage is vital otherwise it will result in the propagation of the crack to the surface. y
Crater cracks tend to appear where there has been an interruption to the welding operation. These usually proceed to the edge of the crater and may be the starting point for longitudinal weld cracks.
Weld metal cracking can usually be reduced by taking one or more of the following actions: y Improve the contour or composition of the weld deposit by changing h i the h electrode l d manipulation or electrical conditions y Increase the thickness of the deposit and provide more weld metal to resist the stresses by decreasing the travel speed y Reduce thermal stress by pre preheating y Use low-hydrogen electrodes y Balance shrinkage stress by sequencing weld deposits y Avoid rapid cooling conditions
Weld e d Discontinuities sco u es a and d their e Causes Causes: C Cracks ac s Underbead cracking is limited mainly i l to steel, l they h are usually ll found at regular intervals under the weld metal , they cannot be d t t db detected by visual i l iinspection. ti Toe cracks are generally the result of strains caused by thermal shrinkage acting on a heat affected zone which has been embrittled. They sometimes occur when the base metal cannot accommodate the shrinkage strains that are imposed by welding. Base metal crack reduction can be reduced by: preheating, controlled heat input p and d correct o electrode od and material selection.
Weld Discontinuities and their Causes: Incomplete Joint Penetration
Incomplete joint penetration is generally associated with groove welds. It may result from insufficient welding heat, improper joint design or generally poor welding ldi technique h i
Examples of poor welding techniques h i are: y Using electrodes that are too large g for the g groove to be welded y Travelling too fast y Using welding currents that are too low Incomplete penetration is always l undesirable d i bl iin welds, especially in single groove welds where the root of the weld is subject either to tension or bending stresses
Examples of joint designs both correct and incorrect. All of the incorrect examples can lead to problems occurring with incomplete joint penetration, or in some cases excessive joint penetration which can have serious implications to the credibilityy of the weld also.
Weld Discontinuities and their Causes: Incomplete Fusion Incomplete p fusion mayy occur at any point in a groove or fillet weld, including the root of the weld weld. Often the weld metal simply rolls over onto the plate surface. Generally this is referred to as overlap. In many cases the weld has good fusion at the h root and d at the h plate l surface, but because of poor technique p q and insufficient heat, the toe of the weld does not fuse.
Weld Discontinuities and their Causes: Incomplete Fusion
IIncomplete l t ffusion i di discontinuities ti iti affect joint integrity in much the same way as porosity or slag inclusions. inclusions
The diagrams opposite show variations i ti off incomplete i l t fusion and overlap in some commonly used weld preparations Causes of preparations. incomplete fusion include the following: y Insufficient heat due to low welding currents, high travels speeds or an arc gap that is too short. y Wrong size or type of electrode y Poor base metal p preparation p y Improper joint design y Inadequate gas shielding
Weld Discontinuities and their Causes: Undercut • Undercut is the groove
melted lt d into i t th the b base metal t l beside the weld. It is the result of the arc removing more material from the joint face than is being replaced by the weld metal. Undercutting is normallyy caused myy improper electrode manipulation. Other causes include: • Using too high a current • Having an arc gap that is too long • Failing to fill up the crater completely with weld metal
Weld Discontinuities and their Causes: Arc Strikes and Spatter y Arc strikes are small, localized
points i where h surface f melting li occurs away from the welded joint. The spots may be caused by striking the arc in the wrong place or by faulty earth connections. y Striking the arc on the base metal th t will that ill nott b be welded ld d should h ld b be avoided. Arc strikes can cause hardness zones in the base metal propagation p g and mayy become a p point for cracking.
Spatter is made up of very fine particles of metal on the plate surface adjoining the weld area. It is usuallyy caused db by h high h current, a long arc, an irregular or unstable arc or improper shielding. Spatter makes a poor appearance on the weld and can make inspection difficult. Both of these discontinuities as well as many others can more often than not be put down to operator error.
Components p of a Welded Joint Before B f carrying i outt any visual i l inspections i ti it is i vital it l tto b be familiar with the components and the terminology related to welded joints. We can categorise welds into either “fillet” fillet or “butt” welds regardless of the material and process usage. Butt welds are commonly referred to as “grooves.”
Typical fillet weld
Typical butt weld
Fillet Welds A fillet weld is a weld that is approximately triangular in cross section and is used with T lap and corner joints. T, joints The sizes and locations of fillet welds are usually given as welding symbols. symbols The two types of fillet welds are “convex” and “concave”. A convex fill fillett weld ld h has it its surface bowed out like the outside surface of a ball. A concave fillet fill t weld ld h has it its surface bowed in like the inside of a bowl.
Fillet Welds cont’d. The following g terms are used to describe a fillet weld: • Weld face- The exposed surface of the weld •LegLeg The distance from the root of the joint to the toe of a fillet weld •Weld toe- The junction between the face of a weld and the base metal •Weld root- The point shown in the cross section at which the metal intersects with the base metal and extends farthest away into the weld joint •Size- The leg lengths of the largest right triangle that can be drawn within the cross section of a fillet weld •Actual A l throath Th shortest The h distance di ffrom the h root off the h weld ld to iits fface •Effective throat- The minimum distance, minus any convexity, from the root of the weld to its face •Theoretical throat- The distance from the beginning of the joint root that is perpendicular to the hypotenuse of the largest right angle triangle that can be inscribed within the cross-section of a fillet weld (These terms can be referenced to the sketch section 4 of the handout)
Fillet Welds cont’d. The ideal fillet weld has a uniform concave or convex face, the next slide, shows acceptable p and non-acceptable weld profiles for both fillet and groove welds.
Butt Welds Butt welds should be made with i h a slight li h reinforcement i f (not exceeding �) and with a gradual transition to th b the base metal t l att each h ttoe. Butt welds should not have excess reinforcement, i insufficient ffi i t th throat, t excessive undercut or overlap. If a butt weld has any off these th d defects f t it should be repaired. Commonly, the bead width should not exceed the groove width by more than �.
Cross section of a butt weld
Introduction IIntroduction t d ti The philosophy that often guides the fabrication of welded assemblies and structures is "to to assure weld quality." However, the term "weld quality" is relative. The application determines what is good or bad bad. Generally, any weld is of good quality if it meets appearance pp requirements q and will continue indefinitelyy to do the job for which it is intended. The first step in assuring weld quality is to determine the degree required by the application. A standard should be established based on the service requirements.
Standards “Whatever the standard of quality, all welds should be inspected." Standards designed to impart weld quality may differ from job to job, but the use of appropriate examination techniques can provide assurance that the applicable standards are being met. Whatever the standard of quality, all welds should be inspected, p , even if the inspection p involves nothing g more than the welder looking over his own work after each weld pass. A good-looking weld surface appearance is many times considered indicative of high weld quality quality. However However, surface appearance alone does not assure good workmanship or internal quality.
NDE Methods Non-destructive examination (NDE) methods of inspection make it possible to verify compliance to the standards on an ongoing basis by examining the surface and subsurface of the weld and surrounding base material. Five basic methods are commonly used to examine finished welds: visual, liquid penetrant, magnetic i particle, i l ultrasonic l i and d radiographic di hi (X (X-ray). ) The growing use of computerization with some methods provides added image p g enhancement,, and allows realtime or near real-time viewing, comparative inspections and archival capabilities. A review of each method will help in deciding which process or combination of processes to use for a specific job and in performing the examination most effectively.
Visual Inspection p Visual inspection is often the most cost cost-effective effective method, method but it must take place prior to, during and after welding. Many standards require its use before other methods, because there is no point in submitting an obviously b i l b bad d weld ld to sophisticated hi i d inspection i i techniques. h i The Th ANSI/AWS D1.1, Structural Welding Code-Steel, states, "Welds subject to non-destructive examination shall have been found acceptable by visual inspection." Visual inspection requires little equipment. Aside from good eyesight and sufficient light, all it takes is a pocket rule, a weld size g gauge, g , a magnifying g y gg glass,, and p possiblyy a straight g edge g and square for checking straightness, alignment and perpendicularity. "Visual inspection is the best buy in NDE, but it must take place prior to, during and after welding."
Visual Inspection: p Pre-Welding g Before the first welding arc is struck, materials should be examined to see if they meet specifications for quality, type, size, cleanliness paint, oil, oxide film or heavyy and freedom from defects. Grease, p scale should be removed. The pieces to be joined should be checked for flatness, straightness and dimensional accuracy. Likewise, alignment, fit-up and joint preparation should be examined. Finally, process and procedure variables should be verified, verified including electrode size and type, equipment settings and provisions for preheat or postheat, (refer to handout 4 Welding Procedure). All of these precautions apply regardless of the inspection method being used. During fabrication, visual examination of a weld bead and the end crater may reveal problems such as cracks, inadequate penetration, and d gas or slag l inclusions. l Among the h weld ld d detects that h can b be recognized visually are cracking, surface slag in inclusions, surface porosity and undercut.
Visual Inspection: p Pre-Welding g On simple welds, welds inspecting at the beginning of each operation and periodically as work progresses may be adequate. Where more than one layer of filler metal is being deposited, however, it may be p each layer y before depositing p g the next. The root desirable to inspect pass of a multi-pass weld is the most critical to weld soundness. It is especially susceptible to cracking, and because it solidifies quickly, it may trap gas and slag. On subsequent passes, conditions caused by the shape of the weld eld bead or changes in the joint config configuration ration can cause further cracking, as well as undercut and slag trapping. Repair costs can be minimized if visual inspection detects these flaws before welding progresses progresses. Visual inspection at an early stage of production can also prevent underwelding and “overwelding”. overwelding . Welds that are smaller than “underwelding” called for in the specifications cannot be tolerated. Beads that are too large increase costs unnecessarily and can cause distortion through added shrinkage stress.
Visual Inspection: p Post welding g After welding welding, visual inspection can detect a variety of surface flaws, including cracks, porosity and unfilled craters,, regardless g of subsequent q inspection p procedures. p Dimensional variances, distortion and appearance flaws, as well as weld size characteristics, can be evaluated. Before checking for surface flaws flaws, welds must be cleaned of slag. Shotblasting should not be done before examination,, because the peening p g action mayy seal fine cracks and make them invisible. The AWS D1.1 Structural Welding Code, for example, does not allow peening "on on the root or surface layer of the weld or the base metal at the edges of the weld."
Visual Inspection p An important aspect of visual inspection is checking the dimensional accuracy of the weld after it has been completed. p Dimensional accuracyy is determined byy conventional measuring gauges, their purpose being to determine if the completed weldment is within tolerable limits as defined by applicable codes and specifications specifications. Four of the most commonly used gauges are the following: y Undercut gauge (trade term term- “Bridge Bridge Cam Gauge�) Gauge ) y Butt weld reinforcement gauge y Fillet weld blade gauge set y Hi-Lo gauge
Undercut Gauges g This is used to measure the amount of undercut on the base metal. These gauges have a pointed end that is pushed into the undercut, the reverse side indicates the measurement in millimetres or iinches. h Th The “B “Bridge id C Cam Gauge� has many other functions also capable of measuring preparation angles, fillet weld lengths, reinforcements, throat dimensions d e so sa and d misalignments, a very functional and versatile product.
1.Butt Weld Reinforcement Gauge and 2.Fillet Weld Blade Gauge Set 2. The Th fillet fill t weld ld bl blade d gauge has seven individual blade gauges for measuring convex and concave welds. 1.The Butt weld gauge g has a reinforcement g sliding pointer calibrated to several different scales that are used to measure the size of a fillet weld or the reinforcement of a butt weld. weld
Hi-Lo Gauge g The Hi-Lo g gauge g has multiple functions: y Measuring internal misalignments i li off pipes i y Measuring pipe wall thicknesses y Measuring fit up gaps y Fillet weld gauging y Measuring reinforcement of butt welds y Standard bevel angle gauge for piping
Radiographic Inspection (RT) Radiography is based on the ability of X-rays and gamma rays to pass through h h metall and d other h materials opaque to ordinary light, and produce photographic records of the transmitted radiant energy. All materials will absorb known amounts of this radiant energy and, therefore, X-rays and gamma rays can be used to show discontinuities and inclusions within the opaque material. The permanent film fil record d off the h iinternall conditions di i will show the basic information by which weld soundness can be determined. Radiographic equipment produces radiation that can be harmful to body tissue in excessive amounts, so all safety precautions should be followed closely. All instructions should be followed carefully to achieve satisfactory results. Only personnel who are trained in radiation safety and qualified as industrial radiographers should be permitted to do radiographic testing.
Magnetic ag et c Particle a t c e Inspection spect o (MT) ( ) Magnetic particle inspection is a method of locating and defining discontinuities in magnetic materials It is excellent for detecting surface defects in welds, including discontinuities that are too small ll to be b seen with i h the h naked eye, and those that are slightly subsurface. This method may be used to inspect plate edges prior to welding, in process inspection of eac o each weld e d pass o or layer, aye , postweld evaluation and to inspect repairs.
Dye y Penetrant Inspection p Surface cracks and p pinholes that are not visible to the naked eye can be located by liquid penetrant inspection. It is widely used to locate leaks in welds and can be applied with austenitic steels and nonferrous materials where magnetic particle inspection would be useless useless. Liquid penetrant inspection is often referred to as an extension of the visual inspection method. h d Many standards, d d such h as the AWS D1.1 Code, say that "welds subject j to liquid q penetrant p testing g ... shall be evaluated on the basis of the requirements for visual inspection."
Liquid penetrant inspection is a nond destructive i method h d ffor llocating i d defects f that h are open to the surface, it cannot detect internal defects! The technique is based on the ability of a penetrating t ti li liquid, id which hi h iis usually ll red d iin colour, to wet the surface opening of a discontinuity and be drawn into it, known as capillary action. action � The inspection is a three step “capillary process:
1. Liquid penetrant is sprayed onto the surface of the weld. Note thorough cleaning must be observed before commencement as any dirt or rust present could block cracks and inhibit the penetrants ability. ability 2. A cleaner is applied to remove excess penetrant. 3. A dry powder developer, which is usually white in colour, is then applied over p If a flaw is significant, g , red dp penetrant b bleeds d through o g the white the specimen. developer to indicate a discontinuity or defect.
Dye y Penetrant Inspection p Advantages y Can find small defects not visible to the naked eye y Usable on most metals y Relatively inexpensive y Easy to interpret results with little training
Disadvantages y Takes more time than other p processes to view results y Can only y find surface defects y Interpretation p can sometimes be distorted y Obvious chemical hazard
Ultrasonic Inspection (UT) y Ultrasonic Inspection is a method
of detecting discontinuities by directing a high-frequency sound beam through the base plate and weld on a predictable path. When the sound beam's path strikes an interruption in the material continuity, some of the sound is reflected back. The sound is collected ll t d by b the th instrument, i t t amplified and displayed as a vertical trace on a video screen. Both surface and subsurface d f defects in i metals l can b be d detected, d located and measured by ultrasonic inspection, including flaws too small to be detected byy other h methods. h d Very h high h skill k ll llevell required to carry out UT procedures.
Inspection p of Weld Samples p I have h brought b ht along l six i weld ld samples l off various i thicknesses and configurations, given the information received today and in your handouts handouts, please take the time to inspect all six pieces, and note down the defects found through the visual inspection of the pieces in sheet 5 of the handouts.
Non Destructive Testing and Welding Applications Supplementary Information Information.
1. 2. 3. 4. 5. 6.
CONTENTS ASME B31 CODE AWS D1.1 STRUCTURAL WELDING CODE API 1104 FILLET WELD DIAGRAM SAMPLE WELDING PROCEDURE VISUAL INSPECTION RESULTS
ASME B31-Standards of Pressure Piping
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B31 Code for pressure piping, developed by American Society of Mechanical Engineers - ASME, covers Power Piping, Fuel Gas Piping, Process Piping, Pipeline Transportation Systems for Liquid Hydrocarbons and Other Liquids, Refrigeration Piping and Heat Transfer Components and Building Services Piping. ASME B31 was earlier known as ANSI B31. B31.1 - 2001 - Power Piping Piping for industrial plants and marine applications. This code prescribes minimum requirements for the design, materials, fabrication, erection, test, and inspection of power and auxiliary service piping systems for electric generation stations, industrial institutional plants, central and district heating plants. The code covers boiler external piping for power boilers and high temperature, high pressure water boilers in which steam or vapour is generated at a pressure of more than 15 PSIG; and high temperature water is generated at pressures exceeding 160 PSIG and/or temperatures exceeding 250 degrees F. B31.2 - 1968 - Fuel Gas Piping This has been withdrawn as a National Standard and replaced by ANSI/NFPA Z223.1, but B31.2 is still available from ASME and is a good reference for the design of gas piping systems (from the meter to the appliance). B31.3 - 2002 - Process Piping Design of chemical and petroleum plants and refineries processing chemicals and hydrocarbons, water and steam. This Code contains rules for piping typically found in petroleum refineries; chemical, chemical pharmaceutical, pharmaceutical textile, textile paper, paper semiconductor, semiconductor and cryogenic plants; and related processing plants and terminals. This Code prescribes requirements for materials and components, design, fabrication, assembly, erection, examination, inspection, and testing of piping. This Code applies to piping for all fluids including: (1) raw, intermediate, and finished chemicals; (2) petroleum products; (3) gas, steam, air and water; (4) fluidized solids; (5) refrigerants; and (6) cryogenic fluids. Also included is piping which interconnects pieces or stages within a packaged equipment assembly. B31.4 - 2002 - Pipeline Transportation Systems for Liquid Hydrocarbons and Other Liquids This Code prescribes requirements for the design design, materials materials, construction construction, assembly assembly, inspection, inspection and testing of piping transporting liquids such as crude oil, condensate, natural gasoline, natural gas liquids, liquefied petroleum gas, carbon dioxide, liquid alcohol, liquid anhydrous ammonia and liquid petroleum products between producers' lease facilities, tank farms, natural gas processing plants, refineries, stations, ammonia plants, terminals (marine, rail and truck) and other delivery and receiving points. Piping consists of pipe, flanges, bolting, gaskets, valves, relief devices, fittings and the pressure containing parts of other piping components. It also includes hangers and supports, and other equipment items necessary to prevent overstressing the pressure containing parts. It does not include support pp structures such as frames of buildings, g , buildings g stanchions or foundations
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Requirements for offshore pipelines are found in Chapter IX. Also included within the scope of this Code are: (A) Primary and associated auxiliary liquid petroleum and liquid anhydrous ammonia i piping i i at pipeline i li terminals i l ((marine, i rail il and d truck), k) tank k ffarms, pump stations, pressure reducing stations and metering stations, including scraper traps, strainers, and prover loop; (B) Storage and working tanks including pipe-type storage fabricated from pipe and fittings, and piping interconnecting these facilities; (C) Liquid petroleum and liquid anhydrous ammonia piping located on property which has been set aside for such piping within petroleum refinery, natural gasoline,, gas g g p processing, g, ammonia,, and bulk plants; p ; (D) Those aspects of operation and maintenance of liquid pipeline systems relating to the safety and protection of the general public, operating company personnel, environment, property and the piping systems. B31.5 - 2001 - Refrigeration Piping and Heat Transfer Components This Code prescribes requirements for the materials, design, fabrication, assembly, erection, test, and inspection of refrigerant, heat transfer components, and secondary coolant piping for temperatures as low as -320 deg F (-196 deg C), whether erected on the premises or factory assembled assembled, except as specifically excluded in the following paragraphs. Users are advised that other piping Code Sections may provide requirements for refrigeration piping in their respective jurisdictions. This Code shall not apply to: (a) any self- contained or unit systems subject to the requirements of Underwriters Laboratories or other nationally recognized testing laboratory: (b) water piping; (c) piping designed for external or internal gage pressure not exceeding 15 psi (105 kPa) regardless of size; or (d) pressure vessels, compressors, or pumps, but does include all connecting refrigerant and secondary coolant piping starting at the first joint adjacent to such apparatus.
ASME B31-Standards of Pressure Piping
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B31.8 - 2003 - Gas Transmission and Distribution Piping Systems This Code covers the design, fabrication, installation, inspection, and testing of pipeline i li facilities f ili i used d ffor the h transportation i off gas. This hi Code d also l covers safety f aspects of the operation and maintenance of those facilities. y B31.8S-2001 - 2002 - Managing System Integrity of Gas Pipelines This Standard applies to on-shore pipeline systems constructed with ferrous materials and that transport gas. y Pipeline system means all parts of physical facilities through which gas is transported, including pipe, valves, appurtenances attached to pipe, compressor units metering stations, units, stations regulator stations, stations delivery stations stations, holders and fabricated assemblies The principles and processes embodied in integrity management are applicable to all pipeline systems. This Standard is specifically designed to provide the operator (as defined in section 13) with the information necessary to develop and implement an effective integrity management program utilizing proven industry practices and processes. The h processes and d approaches h within h this h Standard d d are applicable l bl to the h entire pipeline system. y B31.9 - 1996 - Building Services Piping This Code Section has rules for the piping in industrial, institutional, commercial and public buildings, and multi-unit residences, which does not require the range of sizes, pressures, and temperatures covered in B31.1. This Code prescribes requirements for the design, materials, fabrication, installation, inspection examination and testing of piping systems for building services. inspection, services It includes piping systems in the building or within the property limits. y B31.11 - 2002 - Slurry Transportation Piping Systems Design, construction, inspection, security requirements of slurry piping systems. Covers piping systems that transport aqueous slurries of no hazardous materials, such as coal, mineral ores and other solids between a slurry processing plant and the receiving plant. y B31G - 1991 - Manual for Determining g Remaining g Strength g of Corroded Pipelines p A supplement To B31 Code-Pressure Piping
AWS D1.1, Structural Welding Code-Steel y y
1.1 Scope This code contains the requirements for fabricating and erecting welded steel structures. When this code is stipulated in contract documents, conformance with i h all ll provisions i i off the h code d shall h ll b be required, i d except ffor those h provisions i i that h the Engineer (see 1.4.1) or contract documents specifically modifies or exempts. The following is a summary of the code clauses:
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1. General Requirements. This clause contains basic information on the scope and limitations of the code, key definitions, and the major responsibilities of the parties involved with steel fabrication. 2 Design of Welded Connections. 2. Connections This clause contains requirements for the design of welded connections composed of tubular, or nontubular, product form members. 3. Prequalification. This clause contains the requirements for exempting a WPS (Welding Procedure Specification) from the WPS qualification requirements of this code. 4. Qualification. This clause contains the requirements qualification and the qualification q tests required q for WPS q to be passed by all welding personnel (welders, welding operators, and tack welders) to perform welding in accordance with this code. 5. Fabrication. This clause contains general fabrication and erection requirements applicable to welded steel structures governed by this code, including the requirements for base metals, welding consumables, welding technique, welded details, material preparation and assembly, workmanship, weld ld repair, i and d other h requirements. i 6. Inspection. This clause contains criteria for the qualifications and responsibilities of inspectors, acceptance criteria for production welds, and standard procedures for performing visual inspection and NDT (non-destructive testing). 7. Stud Welding. This clause contains the requirement for the welding of studs to structural steel.
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AWS D1.1, Structural Welding Code-Steel
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8. Strengthening g g and Repair p of Existing g Structures. This clause contains basic information pertinent to the welded modification or repair of existing steel structures.
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1.2 Limitations The code was specifically developed for welded steel structures that utilize carbon or low alloy steels that are 1/8 in [3 mm] or thicker with a minimum specified yield strength of 100 ksi [690 MPa] or less. The code may be suitable to govern structurall fabrications f b i i outside id the h scope off the h iintended d d purpose. H However, the h Engineer should evaluate such suitability, and based upon such evaluations, incorporate into contract documents any necessary changes to code requirements to address the specific requirements of the application that is outside the scope of the code. The Structural Welding Committee encourages the Engineer to consider the applicability of other AWS D1 codes for applications involving aluminium (AWS D1.2), sheet steel equal to or less than 3/16 in thick [5 mm] (AWS D1.3), reinforcing steel (AWS D1.4), and stainless steel (AWS D1.6). The AASHTO/AWS D1.5 D1 5 Bridge Welding Code was specifically developed for welding highway bridge components and is recommended for those applications.
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1.3 Definitions The welding terms in this code shall be interpreted in conformance with the definitions given in the latest edition of AWSA3.0, Standard Welding Terms and Definitions, supplemented by Annex K of this code and the following definitions:
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1.3.1 Engineer. “Engineer� shall be defined as a duly designated individual who acts for, and in behalf of, the Owner on all matters within the scope of the code
API 1104 Section 4 Welding Procedure
Weld Terminologies
Sample Weld Visual Findings Sample Number 1. 25mm Plate Open V-Groove Root run and Hot Pass.(SMAW) 2. 12mm Plate Open V-Grooveincomplete. (SMAW) 3. 12mm Plate, Full Penetration-MultiRun fillet fillet.(SMAW) (SMAW) 4. . 25mm Plate Open V-Groove Root run and Hot Pass. (SMAW) 5. 12mm Plate Open V-Groove-three run bead cap. .(SMAW) 6. 12mm plate Multi-Run fillet.(FCAW) Dye Penetrant Test Specimen.
Defects