Api571 parta1 by charlie Chong

Damage Mechanisms Affecting Fixed Equipment in the Refining Industry 影响炼油行业固定设备的损伤机理 2013年内部培训

中国固有领土: 钓鱼岛 Charlie Chong/ Fion Zhang

印度支那不就是 “Indo-China” 吗?, 中华人民共和国不就是 “People Republic of China”. 这 “China” 或 “支那” 不是歧视字眼.“支那”是个威震四方的大国,以前郑和下西洋的“支那“这是闻之丧胆字眼,现在我们也不渐渐变成”强大支那”了吗?. 小的时候(40年前),友族,善意的叫我“中华人”,我很善意的告诉他,我叫“支那人”,虽然我只是东南亚华裔,但我永远以“支那-China" 引以为荣. 我爱中国,我爱 "China" 我爱"支那".

中国固有领土: 钓鱼岛

http://news.ifeng.com/world/detail_2014_03/20/34944726_0.shtml Charlie Chong/ Fion Zhang

影响炼油行业固定设备的损伤机理-2013年内部培训

http://www.smt.sandvik.com/en/search/?q=stress+corrosion+cracking

Speaker: Fion Zhang 2013/7/4

Adobe Acrobat Reader Hotkeys http://allhotkeys.com/adobe_acrobat_reader_hotkeys.html Ctrl + G = find again Ctrl + L = full screen Ctrl + M = zoom to Ctrl + N = go to page (insert number in box) Ctrl + Q = quit program Ctrl + + = zoom in Ctrl + - = zoom out Ctrl + 0 = fit in window Ctrl + 1 = actual size Ctrl + 2 = fit width Ctrl + 3 = fit visible Ctrl + 4 = reflow Ctrl + Shift + A = deselect all Ctrl + Shift + F = search query Ctrl + Shift + G = search results Ctrl + Shift + J = cascade windows Ctrl + Shift + K = tile windows horizontally Ctrl + Shift + L = tile windows vertically

Ctrl + Shift + S = save a copy Ctrl + Shift + P = page setup Ctrl + Shift + W = search word assistant Ctrl + Shift + X = search select indexes Ctrl + Shift + Page Up = first page Ctrl + Shift + Page Down = last page Ctrl + Shift + + = rotate clockwise Ctrl + Shift + - = rotate counterclockwise Ctrl + Alt + W = close all Alt + Left Arrow = go to previous view Alt + Right Arrow = go to next view Alt + Shift + Left Arrow = go to previous document Alt + Shift + Right Arrow = go to next document F4 = thumbnails F5 = bookmarks F8 = hide toolbars F9 = hide menu bar http://en.wikipedia.org/wiki/Table_of_keyboard_shortcuts http://help.adobe.com/en_US/acrobat/using/WS58a04a822e3e50102bd615109794195ff-7aed.w.html

For API 510 ICP - API RP 571, Damage mechanisms Affecting Fixed equipment in the Refining Industry ATTN: Examination questions will be based on the following sections only: Par. 3. 4.2.3 4.2.7 4.2.9 4.2.14 4.2.16 4.3.2 4.3.3 4.3.4 4.3.5 4.3.10 4.4.2 4.5.1 4.5.2 4.5.3 5.1.2.3 5.1.3.1

– Definitions (included as a frame of reference only) – Temper Embrittlement – Brittle Fracture – Thermal Fatigue – Erosion/Erosion-Corrosion – Mechanical Failure – Atmospheric Corrosion – Corrosion Under Insulation (CUI) – Cooling Water Corrosion – Boiler Water Condensate Corrosion – Caustic Corrosion – Sulfidation – Chloride Stress Corrosion Cracking (Cl-SCC) – Corrosion Fatigue – Caustic Stress Corrosion Cracking (Caustic Embrittlement) – Wet H2S Damage (Blistering / HIC/ SOHIC/ SSC) – High Temperature Hydrogen Attack (HTHA)

For API 570 ICP -

API RP 571, Damage mechanisms Affecting Fixed equipment in the Refining Industry ATTN: Examination questions will be based on the following sections only: Par. 3 4.2.7 4.2.9 4.2.14 4.2.16 4.2.17 4.3.1 4.3.2 4.3.3 4.3.5 4.3.7 4.3.8 4.3.9 4.4.2 4.5.1 4.5.3 5.1.3.1

– Definitions (included as a frame of reference only) – Brittle Fracture – Thermal Fatigue – Erosion/Erosion Corrosion – Mechanical Fatigue – Vibration-Induced Fatigue – Galvanic Corrosion – Atmospheric Corrosion – Corrosion Under Insulation (CUI) – Boiler Water Condensate Corrosion – Flue Gas Dew Point Corrosion – Microbiological Induced Corrosion (MIC) – Soil Corrosion – Sulfidation – Chloride Stress Corrosion Cracking (Cl-SCC) – Caustic Stress corrosion Cracking (Caustic Embrittlement) – High Temperature Hydrogen Attack (HTTA)

BODY OF KNOWLEDGE API-510 PRESSURE VESSEL INSPECTOR CERTIFICATION EXAMINATION August 2010 (Replaces January 2009)

API RP 571, Damage Mechanisms Affecting Fixed equipment in the Refining Industry ATTN: API 510 Test questions will be based on the following mechanisms only: Par. 3. - Definitions (included as a frame of reference only) 1. 4.2.3 – Temper Embrittlement 2. 4.2.7 – Brittle Fracture 3. 4.2.9 – Thermal Fatigue 4. 4.2.14 – Erosion/Erosion-Corrosion 5. 4.2.16 – Mechanical Failure 6. 4.3.2 – Atmospheric Corrosion 7. 4.3.3 – Corrosion Under Insulation (CUI) 8. 4.3.4 – Cooling Water Corrosion 9. 4.3.5 – Boiler Water Condensate Corrosion 10. 4.3.10 – Caustic Corrosion 11. 4.4.2 – Sulfidation 12. 4.5.1 – Chloride Stress Corrosion Cracking (Cl-SCC) 13. 4.5.2 – Corrosion Fatigue 14. 4.5.3 – Caustic Stress Corrosion Cracking (Caustic Embrittlement) 15. 5.1.2.3 – Wet H2S Damage (Blistering/HIC/SOHIC/SCC) 16. 5.1.3.1 – High Temperature Hydrogen Attack (HTHA)

BODY OF KNOWLEDGE API-570 AUTHORIZED PIPING INSPECTOR CERTIFICATION EXAMINATION August 2010 (Replaces June 2007)

API RP 571, Damage mechanisms Affecting Fixed equipment in the Refining Industry ATTN: API 570 Examination questions will be based on the following sections only: Par. 3 – Definitions (included as a frame of reference only) 1. 4.2.7 – Brittle Fracture 2. 4.2.9 – Thermal Fatigue 3. 4.2.14 – Erosion/Erosion Corrosion 4. 4.2.16 – Mechanical Fatigue 5. 4.2.17 – Vibration-Induced Fatigue 6. 4.3.1 – Galvanic Corrosion 7. 4.3.2 – Atmospheric Corrosion 8. 4.3.3 – Corrosion Under Insulation (CUI) 9. 4.3.5 – Boiler Water Condensate Corrosion 10. 4.3.7 – Flue Gas Dew Point Corrosion 11. 4.3.8 – Microbiological Induced Corrosion (MIC) 12. 4.3.9 – Soil Corrosion 13. 4.4.2 – Sulfidation 14. 4.5.1 – Chloride Stress Corrosion Cracking (Cl-SCC) 15. 4.5.3 – Caustic Stress corrosion Cracking (Caustic Embrittlement)

2013- API570 Examination

2013-API510 Examination

Par. 3 – Definitions

Par. 3. - Definitions

4.2.7 – Brittle Fracture

4.2.3 – Temper Embrittlement

4.2.9 – Thermal Fatigue

4.2.7 – Brittle Fracture

4.2.14 – Erosion/Erosion Corrosion

4.2.9 – Thermal Fatigue

4.2.16 – Mechanical Fatigue

4.2.14 – Erosion/Erosion-Corrosion

4.2.17 – Vibration-Induced Fatigue

4.2.16 – Mechanical Failure

4.3.1 – Galvanic Corrosion

4.3.2 – Atmospheric Corrosion

4.3.3 – Corrosion Under Insulation (CUI)

4.3.4 – Cooling Water Corrosion

4.3.5 – Boiler Water Condensate Corrosion

4.3.7 – Flue Gas Dew Point Corrosion

4.3.10 – Caustic Corrosion

4.3.8 – Microbiological Induced Corrosion (MIC)

4.4.2 – Sulfidation

4.3.9 – Soil Corrosion

4.5.1 – Chloride Stress Corrosion Cracking (Cl-SCC)

4.4.2 – Sulfidation

4.5.2 – Corrosion Fatigue

4.5.1 – Chloride Stress Corrosion Cracking (Cl-SCC)

4.5.3 – Caustic Stress Corrosion Cracking

4.5.3 – Caustic Stress corrosion Cracking

5.1.2.3 – Wet H2S Damage (Blister/HIC/SOHIC/SCC)

5.1.3.1 – High Temperature Hydrogen Attack (HTTA)

5.1.3.1 – High Temperature Hydrogen Attack (HTHA)

Mechanical and Metallurgical Failure Mechanisms 机械和冶金失效机理 Graphitisation 石墨化

API510

800oF for C Steel

Plain carbon steel

875oF for C ½ Mo Steel

C- ½ Mo

Spheroidisation 碳化物球状

850oF ~ 1400oF

Low alloy steel up to 9% Cr

Tempered Embrittlement

650oF~ 1070oF

2 ¼ Cr-1Mo low alloy steel, 3Cr1Mo (lesser extent), & HSLA CrMo-V rotor steels

Strain Aging 延伸时效

Intermediate temperature

Pre-1980’s C-steels with a large grain size and C- ½ Mo

885oF embrittlement 脆性

600oF~ 1000oF

300, 400 & Duplex SS containing ferrite phases

Sigma-Phase Embrittlement

1000oF~ 1700oF

300, 400 & Duplex SS containing ferrite phases

Below DTBTT

C, C- ½ Mo, 400 SS

回火脆性

σ相脆化 API510

Brittle Fracture

700oF ~ 1000oF

All metals and alloys

Thermal fatigues

Operating temperature

All materials of construction

Short Term Overheating – Stress Rupture 短期过热–应力破裂

>1000oF

All fired heater tube materials and common materials of construction

Steam Blanketing 蒸汽遮盖

>1000oF

Carbon steel and low alloy steels

Creep & stress rupture 蠕变和应力断裂 API510

Dissimilar Metal Weld (DMW) Operating temperature Cracking

Carbon steel / 300 SS junction

Thermal Shock 温度突然变

Cold liquid impinge on hot surface

All metals and alloys.

Flue-gas dew-point corrosion

H2SO4-280oF (138oC), HCL-130oF (54oC).

CS, low alloy and 300 SS

CUI

10oF (–120C) and 350oF (175oC)

C-Steel and low alloy steel

140oF (60oC) and 400oF (205oC)

austenitic stainless steels and duplex stainless steels

High Temperature Corrosion [>400oF (204oC)]

API510

Oxidation

CS - >1000oF (538oC)

氧化

300SS- >1500oF (816oC).

Sulfidation

Iron based alloy 500oF (260oC).

硫腐蚀

Others ?

Carburization 渗碳

>1100oF (593oC)

All metals and alloys

Decarburization

CS and low alloy steel

900oF ~1500oF（482oC~ 816oC）

All metals and alloys All metals and alloys

燃料灰腐蚀

> 700oF(371oC), varies with melting point of salts formed.

Nitriding

>600oF (316oC)

Carbon steels, low alloy steels, 300 Series SS and 400 Series SS

All metals and alloys

脱碳 Metal dusting 金属尘化 Fuel ash corrosion

渗氮

今日课程: 0900~1130hrs 第一篇: 第一章至第三章- 大纲与定义第二篇: 第四章- 一般损伤机制 - 所有行业 1300~1700hrs 第三篇: 第五章- 炼油行业损坏机理第四篇: Q&A 问与答

FOREWORD 前言 The overall purpose of this document is to present information on equipment damage mechanisms in a set format to assist the reader in applying the information in the inspection and assessment of equipment from a safety and reliability standpoint. 本文件的总体目标从安全性和可靠性的角度, 用预设的文件格式, 提供设备损坏机理信息,以协助读者应用此信息协助设备的(1) 检查和 (2) 评估.

这份文件反映了行业信息,但它不是一个强制性的标准或规范.这作业指导 “Recommended practice 571” 是作为 API 检验规范如 API 510, API 570, API 653 和执行基于风险的检验API 580/API 581提供有用的信息本出版物中包含的综合指导,考虑的事项有:  可能会影响工艺设备的损伤机理实用信息,  设备上, 有关可以预测到的损伤类型和损害程度,  如何从这些知识帮助选择正确的选择检验方法来发现/鉴定与检测尺寸.

This publication contains guidance for the combined considerations of:  Practical information on damage mechanisms that can affect process equipment, 影响设备损坏机理的实用信息,  Assistance regarding the type and extent of damage that can be expected, and 协助确定设备潜在的损伤类别与损伤程度,  How this knowledge can be applied to the selection of effective inspection methods to detect size and characterize damage. 通过上述的知识确定如何选用真确的探测方法来对损伤定型与定量.

值得留意的是此文件 API571没提到: 材料选择作为损坏机理的防范.同样的是, 在 ASME B31.3 300(6) Compatibility of materials with the service and hazards from instability of contained fluids are not within the scope of this Code. See para. F323. 材料的兼容性对因所含流体(媒介)不稳定造成的危害,不在本规范范围内.

Table of contents 目录 1.0 2.0 3.0 4.0 5.0

Introduction and scope 简介及范围 References 参考 Definition of terms and abbreviations 定义,术语和缩略语 General damage mechanisms – all industries 一般损伤机制 - 所有行业 Refining industry damage mechanisms 炼油行业损坏机理 Appendix a – technical inquiries 附录A - 技术咨询

SECTION 1.0 Introduction and scope 简介及范围

1.1 Introduction 序言 ASME 和 API 加压设备的设计规范和标准-提供设计,制造,检验和测试 “新的” 压力容器,管道系统和储罐的规则. 这些规范不解决设备在服务期间设备的老化, 腐蚀, 损坏等的考虑.这 RP主要针对在役设备上述信息. 在执行适用性评价(FFS),基于风险的检验 (RBI), 也提供需要的信息.因为:  进行 FFS/ API RP 579- FFS 评估第一步是确定(1) 缺陷类型和 (2) 损坏的原因.  基于风险的检验 (RBI) 第一个步骤也是正确的识别系统设备损伤机理或其他形式的恶化原因.

当进行FFS/RBI评估时也作为重点:  观察到的或预测的损坏的原因  未来进一步损坏的可能性和损坏程度化工设施的材料/环境条件相互作用非常多样化.许多不同的处理单元各有其自身的进取过程,媒介组合,不同的温度/压力条件这些不确定因素带给FFS/RBI 评估带来一些难度.

当设备观察到的缺陷时,这缺陷可能是:  使用前新建造,本来缺陷,  在职服务导致的后来缺陷. 在役服务导致的后来缺陷原因有:  设计不足的因素- (包括材料的选择和缺乏设计详细考虑)  设备运行中的腐蚀性的环境/条件引起 - (正常的服务或瞬态期间)

In general, the following types of damage are encountered in petrochemical equipment: 化工设备一般损伤类型 1. 2. 3. 4. 5.

General and local metal loss due to corrosion and/or erosion, 由于腐蚀和/或侵蚀均匀与局部金属减薄 Surface connected cracking, 表面连接开裂 Subsurface cracking, 内表面开裂 Microfissuring/microvoid formation, 微裂纹/微孔形成 Metallurgical changes. 金相变化

基于外观或形态, 损伤分类

SECTION 4.0 GENERAL DAMAGE MECHANISMS – ALL INDUSTRIES 一般损伤机制 - 所有行业 4.2 Mechanical and Metallurgical Failure Mechanisms. 机械和冶金失效机制 4.3 Uniform or Localized Loss of Thickness. 均衡或局部厚度亏损 4.4 High Temperature Corrosion [400°F (204°C)].高温腐蚀 4.5 Environment Assisted Cracking. 环境辅助开裂 SECTION 5.0 REFINING INDUSTRY DAMAGE MECHANISMS 炼油工业的损伤机制 5.1.1 Uniform or Localized Loss in Thickness Phenomena 均匀或局部现象损失厚度 5.1.2 Environment-Assisted Cracking 环境辅助开裂

基于引发因素, 损伤分类

General and local metal loss/ 均匀与局部减薄

General and local metal loss/

均匀与局部减薄

General and local metal loss/ 均匀与局部减薄

Surface connected cracking

SCC or fatigue cracks nucleate at stress concentration points

SCC cracks have highly branch

Corrosion fatigue cracks have little branching

Surface connected cracking

subsurface cracking

Microfissuring/microvoid formation

http://www.aws.org/wj/supplement/WJ_1985_04_s91.pdf

Microfissuring/microvoid formation

http://www.aws.org/wj/supplement/WJ_1985_04_s91.pdf

Metallurgical changes

Each of these general types of damage may be caused by a single or multiple damage mechanisms. In addition, each of the damage mechanisms occurs under very specific combinations of materials, process environments, and operating conditions. 每个损伤,可能是由一个或多个损坏机理造成.每一个损伤机制有非常具体的(1)材料 (2)过程环境和 (3)操作条件,的组合下发生.

1.2 Scope 范围 This recommended practice provides general guidance as to the most likely damage mechanisms affecting common alloys used in the refining and petrochemical industry and is intended to introduce the concepts of serviceinduced deterioration and failure modes. These guidelines provide information that can be utilized by plant inspection personnel to assist in identifying likely causes of damage; to assist with the development of inspection strategies; to help identify monitoring programs to ensure equipment integrity. 此规范对石油化工行业常用材料在役损蚀与失效最可能的损坏机理一般指导. 协助检验人员识别可能导致伤害的原因, 从而确定检测策略, 以确保设备的完整性. The summary provided for each damage mechanism provides the fundamental information required for an FFS assessment performed in accordance with API 579-1/ASME FFS-1 or an RBI study performed in accordance with API RP 580. 每个损伤机理的总结作为提供RBI/FFS评估所需的基本信息.

API571,此规范对石油化工行业常用材料在役损蚀与失效最可能的损坏机理一般指导. 协助检验人员识别可能导致伤害的原因, 从而确定检测策略, 以确保设备的完整性.

1.3 Organization and Use 格式和使用 The information for each damage mechanism is provided in a set format as shown below. This recommended practice format facilitates use of the information in the development of inspection programs, FFS assessment and RBI applications. 为了协助 (1) 检验计划的开发/ (2) FFS 使用性评估 (3) RBI 基于风险分析检验的运用, 个别的损坏机理的信息提供的格式如下:

a) Description of Damage – a basic description of the damage mechanism. 损伤机理的基本描述 b) Affected Materials – a list of the materials prone to the damage mechanism.受影响的材料 c) Critical Factors – a list of factors that affect the damage mechanism (i.e. rate of damage).破坏机理的影响因素列表 d) Affected Units or Equipment – a list of the affected equipment and/or units where the damage mechanism commonly occurs is provided. 受影响的单元或设备 e) Appearance or Morphology of Damage – a description of the damage mechanism, with pictures in some cases, to assist with recognition of the damage.外观或损伤形态学.

f) Prevention / Mitigation – methods to prevent and/or mitigate damage. 预防/缓解 g) Inspection and Monitoring – recommendations for NDE for detecting and sizing the flaw types associated with the damage mechanism. 检查和监测 h) Related Mechanisms – a discussion of related damage mechanisms. 相关的损伤机理讨论 i) References – a list of references that provide background and other pertinent information. 参考.

Damage mechanisms that are common to a variety of industries including refining and petrochemical, pulp and paper, and fossil utility are covered in Section 4.0. 通用炼油化工,纸浆和纸张,以及石化设施- 损坏机理信息 Damage mechanisms that are specific to the refining and petrochemical industries are covered in Section 5. 专门针对炼油和石化工业- 损坏机理信息 In addition, process flow diagrams are provided in 5.2 to assist the user in determining primary locations where some of the significant damage mechanisms are commonly found. 5.2 提供了一些工艺流程图主要的单元常见的一些重大损害机理.

提供损伤机理作为定性定量的信息 提供损伤机理作为FFS/RBI 评估有用的信息 提供损伤机理作为API510/ 570/ 653 在职设备检验有用的信息 损伤机理可以分为5大类型 设备损伤发现可能是源于新建或在职服务导致.

SECTION 2.0 REFERENCES 2.1 Standards 2.2 Other References

2.1 Standards API • API 530 Pressure Vessel Inspection Code • Std. 530 Calculation of Heater Tube Thickness in Petroleum Refineries • RP 579 Fitness-For-Service • Publ. 581 Risk-Based Inspection - Base Resource Document • Std. 660 Shell and Tube Heat Exchangers for General Refinery Service • RP 751 Safe Operation of Hydrofluoric Acid Alkylation Units • RP 932-B Design, Materials, Fabrication, Operation and Inspection Guidelines for Corrosion Control in Hydroprocessing Reactor Effluent Air Cooler (REAC) Systems • RP 934 Materials and Fabrication Requirements for 2-1/4 Cr-1Mo & 3Cr1Mo Steel Heavy Wall Pressure Vessels for High Temperature, High Pressure Service • RP 941 Steels for Hydrogen Service at Elevated Temperatures and Pressures in Petroleum Refineries and Petrochemical Plants • RP 945 Avoiding Environmental Cracking in Amine Units

ASM • Metals Handbook Volume 1, Properties and Selection: Iron, Steels, and High-Performance Alloys; • Volume 13, Corrosion in Petroleum Refining and Petrochemical Operations; • Volume 11, Failure Analysis and Prevention ASME • Boiler and Pressure Vessel Code Section III, Division I, Rules for Construction of Nuclear Power Plant Components; Section VIII, Division I, Pressure Vessels. ASTM • MNL41 Corrosion in the Petrochemical Industry • STP1428 Thermo-mechanical Fatigue Behavior of Materials BSI • BSI 7910 Guidance on Methods for Assessing the Acceptability of Flaws in Fusion Welded Structures MPC • Report FS-26 Fitness-For Service Evaluation Procedures for Operating Pressure Vessels, Tanks and Piping in Refinery and Chemical Service

NACE • • •

• • • • • • •

Std. MR 0103 Materials Resistant to Sulfide Stress Cracking in Corrosive Petroleum Refining Environments” RP 0169 Standard Recommended Practice: Control of External Corrosion on Underground or Submerged Metallic Piping Systems RP 0170 Protection of Austenitic Stainless Steels and Other Austenitic Alloys from Polythionic Acid Stress Corrosion Cracking during Shutdown of Refinery Equipment RP 0198 The Control of Corrosion Under Thermal Insulation, and Fireproofing – A Systems Approach RP 0294 Design, Fabrication, and Inspection of Tanks for the Storage of Concentrated Sulfuric Acid and Oleum at Ambient Temperatures RP 0296 Guidelines for Detection, Repair and Mitigation of Cracking of Existing Petroleum Refinery Pressure Vessels in Wet H2S Environments RP 0472 Methods and Controls to Prevent in-Service Environmental Cracking of Carbon Steel Weldments in Corrosive Petroleum Refining Environments Publ. 5A151 Materials of Construction for Handling Sulfuric Acid Publ. 5A171 Materials for Receiving, Handling, and Storing Hydrofluoric Acid Publ. 8X194 Materials and Fabrication

WRC • Bulletin 32 Graphitization of Steel in Petroleum Refining Equipment and the Effect of Graphitization of Steel on Stress-Rupture Properties • Bulletin 275 The Use of Quenched and Tempered 2-1/4Cr-1Mo Steel for Thick Wall Reactor Vessels in Petroleum Refinery Processes: An Interpretive Review of 25 Years of Research and Application • Bulletin 350 Design Criteria for Dissimilar Metal Welds • Bulletin 409 Fundamental Studies Of The Metallurgical Causes And Mitigation Of Reheat Cracking In 1¼Cr-½Mo And 2¼Cr-1Mo Steels • Bulletin 418 The Effect of Crack Depth (a) and Crack-Depth to Width Ratio (a/W) on the Fracture Toughness of A533-B Steel • Bulletin 452 Recommended Practices for Local Heating of Welds in Pressure Vessels

2.2 Other References A list of publications that offer background and other information pertinent to the damage mechanism is provided in the section covering each damage mechanism.

SECTION 3.0 DEFINITION OF TERMS AND ABBREVIATIONS 3.1 Terms 3.2 Symbols and Abbreviations

3.1 Terms 3.1.1 Austenitic奥氏体– a term that refers to a type of metallurgical structure (austenite) normally found in 300 Series stainless steels and nickel base alloys. 3.1.2 Austenitic stainless steels 奥氏体系不锈钢– the 300 Series stainless steels including Types 304, 304L, 304H, 309, 310, 316, 316L, 316H, 321, 321H, 347, and 347H. The “L” and “H” suffixes refer to controlled ranges of low and high carbon content, respectively. These alloys are characterized by an austenitic structure. 3.1.3 Carbon steel 碳素钢– steels that do not have alloying elements intentionally added. However, there may be small amounts of elements permitted by specifications such as SA516 and SA106, for example that can affect corrosion resistance, hardness after welding, and toughness. Elements which may be found in small quantities include Cr, Ni, Mo, Cu, S, Si, P, Al, V and B.

3.1.4 Di-ethanolamine二乙醇胺 (DEA) – used in amine treating to remove H2S and CO2 from hydrocarbon streams. 3.1.5 Duplex stainless steel 双相不锈钢– a family of stainless steels that contain a mixed austenitic-ferritic structure including Alloy 2205, 2304, and 2507. The welds of 300 series stainless steels may also exhibit a duplex structure. 3.1.6 Ferritic 铁素体– a term that refers to a type of metallurgical structure (ferrite) normally found in carbon and low alloy steels and many 400 series stainless steels. 3.1.7 Ferritic stainless steels 铁素体不锈钢– include Types 405, 409, 430, 442, and 446. 3.1.8 Heat Affected Zone (HAZ) – the portion of the base metal adjacent to a weld which has not been melted, but whose metallurgical microstructure and mechanical properties have been changed by the heat of welding, sometimes with undesirable effects.

Add Nickel

0% Nickel-Ferrite 铁素体

Add Nickel

5% Nickel-Duplex 双相(铁素/奥氏体)

>8% Nickel-Austenite 奥氏体

The 1949 Schaeffler diagram

http://www.intechopen.com/books/environmental-and-industrial-corrosion-practical-and-theoreticalaspects/corrosion-behaviour-of-cold-deformed-austenitic-alloys

3.1.9 Hydrogen Induced Cracking (HIC) 氢致开裂– describes stepwise internal cracks that connect adjacent hydrogen blisters on different planes in the metal, or to the metal surface. No externally applied stress is needed for the formation of HIC. The development of internal cracks (sometimes referred to as blister cracks) tends to link with other cracks by a transgranular plastic shear mechanism because of internal pressure resulting from the accumulation of hydrogen. The link-up of these cracks on different planes in steels has been referred to as stepwise cracking to characterize the nature of the crack appearance. 3.1.10 Low alloy steel 低合金结构钢– a family of steels containing up to 9% chromium and other alloying additions for high temperature strength and creep resistance. The materials include C-0.5Mo, Mn-0.5Mo, 1Cr-0.5Mo, 1.25 Cr-0.5Mo, 2.25Cr-1.0Mo, 5Cr-0.5Mo, and 9Cr-1Mo. These are considered ferritic steels.

3.1.11 Martensitic 马氏体– a term that refers to a type of metallurgical structure (martensite) normally found in some 400 series stainless steel. Heat treatment and or welding followed by rapid cooling can produce this structure in carbon and low alloy steels.

3.1.12 Martensitic stainless steel – include Types 410, 410S, 416, 420, 440A, 440B, and 440C. 3.1.13 Methyldiethanolamine (MDEA) – used in amine treating to remove H2S and CO2 from hydrocarbon streams. 3.1.14 Monoethanolamine (MEA) – used in amine treating to remove H2S and CO2 from hydrocarbon streams. 3.1.15 Nickel base alloy– a family of alloys containing nickel as a major alloying element ( Ni>30% ) including Alloys 200, 400, K-500, 800, 800H, 825, 600, 600H, 617, 625, 718, X-750, and C276.

3.1.16 Stress oriented hydrogen induced cracking (SOHIC) 应力导向氢致开裂– describes an array of cracks, aligned nearly perpendicular to the stress, that are formed by the link-up of small HIC cracks in steel. Tensile strength (residual or applied) is required to produce SOHIC. SOHIC is commonly observed in the base metal adjacent to the Heat Affected Zone (HAZ) of a weld, oriented in the throughthickness direction. SOHIC may also be produced in susceptible steels at other high stress points, such as from the tip of the mechanical cracks and defects, or from the interaction among HIC on different planes in the steel. 3.1.17 Stainless steel 不锈钢– there are four categories of stainless steels that are characterized by their metallurgical structure at room temperature: austenitic, ferritic, martensitic and duplex. These alloys have varying amounts of chromium and other alloying elements that give them resistance to oxidation, sulfidation and other forms of corrosion depending on the alloy content.

3.2 Symbols and Abbreviations 3.2.1 3.2.2 3.2.3 3.2.4 3.2.5 3.2.6 3.2.7 3.2.8 3.2.9 3.2.10 3.2.11 3.2.12 3.2.13 3.2.14 3.2.15

ACFM AE AET AGO AUBT BFW C2 C3 C4 Cat CDU CH4 CO CO2 CVN

– alternating current magnetic flux leakage testing. – acoustic emission. – acoustic emission testing. – atmospheric gas oil. – automated ultrasonic backscatter testing. – boiler feed water. – chemical symbol referring to ethane or ethylene. – chemical symbol referring to propane or propylene. – chemical symbol referring to butane or butylenes. – catalyst or catalytic. – crude distillation unit. – methane. – carbon monoxide. – carbon dioxide. – charpy v-notch.

3.2.16 3.2.17 3.2.18 3.2.19

CW DIB DNB DEA

3.2.20

3.2.21 3.2.22 3.2.23 3.2.24 3.2.25 3.2.26 3.2.27 3.2.28 3.2.29 3.2.30

FCC FMR H2 H2O H2 S HAZ HB HCO HCGO HIC

– cooling water. – deisobutanizer. – Departure from Nucleate Boiling. – diethanolamine, used in amine treating to remove H2S and CO2 from hydrocarbon streams. – eddy current, test method applies primarily to nonferromagnetic materials. – fluid catalytic cracker. – field metallographic replication. – hydrogen. – also known as water. – hydrogen sulfide, a poisonous gas. – Heat Affected Zone – Brinnell hardness numbe – heavy cycle oil. – heavy coker gas oil. – Hydrogen Induced Cracking

571-3 Charlie Chong/ Fion Zhang

3.2.31 3.2.32 3.2.33 3.2.34 3.2.35 3.2.36 3.2.37 3.2.38 3.2.39 3.2.40 3.2.41 3.2.42 3.2.43 3.2.44 3.2.45 3.2.46 3.2.47 3.2.48

HP HPS HVGO HSLA HSAS IC4 IP IRIS K.O. LCGO LCO LP LPS LVGO MDEA MEA mpy MT

– high pressure. – high pressure separator. – heavy vacuum gas oil. – high strength low alloy. – heat stable amine salts. – chemical symbol referring isobutane. – intermediate pressure. – internal rotating inspection system. – knock out, as in K.O. Drum. – light coker gas oil. – light cycle oil. – low pressure. – low pressure separator. – light vacuum gas oil. – methyldiethanolamine. – monoethanolamine. – mils per year. – magnetic particle testing

3.2.49 3.2.50 3.2.51 3.2.52 3.2.53 3.2.54 3.2.55 3.2.56 3.2.57 3.2.58 3.2.59 3.2.60 3.2.61 3.2.62 3.2.63 3.2.64 3.2.65 3.2.66

NAC NH4HS PMI PFD PT RFEC RT SCC SOHIC SS: SW SWS SWUT Ti UT VDU VT WFMT

– naphthenic acid corrosion. – ammonium bisulfide. – positive materials identification. – process flow diagram. – liquid penetrant testing. – remote field eddy current testing. – radiographic testing. – stress corrosion cracking. – Stress Oriented Hydrogen Induced Cracking – Stainless Steel. – sour water. – sour water stripper. – shear wave ultrasonic testing. – titanium. – ultrasonic testing. – vacuum distillation unit. – visual inspection. – wet fluorescent magnetic particle testing.

SECTION 4.0 GENERAL DAMAGE MECHANISMS – ALL INDUSTRIES 一般损伤机制 - 所有行业

4.1 General 大纲 4.2 Mechanical and Metallurgical Failure Mechanisms. 机械和冶金失效机制 4.3 Uniform or Localized Loss of Thickness. 均衡或局部厚度亏损 4.4 High Temperature Corrosion [400°F (204°C)]. 高温腐蚀 4.5 Environment Assisted Cracking. 环境辅助开裂

GENERAL DAMAGE MECHANISMS – ALL INDUSTRIES 一般损伤机制 - 所有行业

美国德克萨斯化肥厂爆炸,死亡人数攀升至35人

GENERAL DAMAGE MECHANISMS – ALL INDUSTRIES 一般损伤机制 - 所有行业

GENERAL DAMAGE MECHANISMS – ALL INDUSTRIES http://edition.cnn.com/2013/04/18/us/texas-explosion/ 一般损伤机制 - 所有行业

GENERAL DAMAGE MECHANISMS – ALL INDUSTRIES 一般损伤机制 - 所有行业

GENERAL DAMAGE MECHANISMS – ALL INDUSTRIES 一般损伤机制 - 所有行业. API 571 人为的把损伤机理分类为4种作为学习; 1. 机械和冶金失效机理, 2. 均衡或局部厚度亏损. 3. 高温腐蚀, 4. 环境辅助开裂

4.2 Mechanical & Metallurgical Failure Mechanisms 机械和冶金失效机理

4.3 Uniform or Localized Loss of Thickness 均衡或局部厚度亏损

4.4 High Temperature Corrosion高温腐蚀

4.5 Environment Assisted Cracking 环境辅助开裂

4.2 Mechanical & Metallurgical Failure Mechanisms 机械和冶金失效机制

4.2 Mechanical and Metallurgical Failure Mechanisms 4.2.1 Graphitization. 4.2.2 Softening (Spheroidization). 4.2.3 Temper Embrittlement. 4.2.4 Strain Aging. 4.2.5 885°F (475°C) Embrittlement. 4.2.6 Sigma Phase Embrittlement . 4.2.7 Brittle Fracture. 4.2.8 Creep and Stress Rupture. 4.2.9 Thermal Fatigue . 4.2.10 Short Term Overheating – Stress Rupture. 4.2.11 Steam Blanketing. 4.2.12 Dissimilar Metal Weld (DMW) Cracking. 4.2.13 Thermal Shock. 4.2.14 Erosion/Erosion – Corrosion. 4.2.15 Cavitation. 4.2.16 Mechanical Fatigue. 4.2.17 Vibration-Induced Fatigue. 4.2.18 Refractory Degradation. 4.2.19 Reheat Cracking. 4.2.20 GOX-Enhanced Ignition & Combustion

2013- API570 Examination

2013-API510 Examination

Par. 3 – Definitions

Par. 3. - Definitions

4.2.7 – Brittle Fracture

4.2.3 – Temper Embrittlement

4.2.9 – Thermal Fatigue

4.2.7 – Brittle Fracture

4.2.14 – Erosion/Erosion Corrosion

4.2.9 – Thermal Fatigue

4.2.16 – Mechanical Fatigue

4.2.14 – Erosion/Erosion-Corrosion

4.2.17 – Vibration-Induced Fatigue

4.2.16 – Mechanical Failure

4.3.1 – Galvanic Corrosion

4.3.2 – Atmospheric Corrosion

4.3.3 – Corrosion Under Insulation (CUI)

4.3.4 – Cooling Water Corrosion

4.3.5 – Boiler Water Condensate Corrosion

4.3.7 – Flue Gas Dew Point Corrosion

4.3.10 – Caustic Corrosion

4.3.8 – Microbiological Induced Corrosion (MIC)

4.4.2 – Sulfidation

4.3.9 – Soil Corrosion

4.5.1 – Chloride Stress Corrosion Cracking (Cl-SCC)

4.4.2 – Sulfidation

4.5.2 – Corrosion Fatigue

4.5.1 – Chloride Stress Corrosion Cracking (Cl-SCC)

4.5.3 – Caustic Stress Corrosion Cracking

4.5.3 – Caustic Stress corrosion Cracking

5.1.2.3 – Wet H2S Damage (Blister/HIC/SOHIC/SCC)

5.1.3.1 – High Temperature Hydrogen Attack (HTTA)

5.1.3.1 – High Temperature Hydrogen Attack (HTHA)

Exam

510

Damage Mechanism

Temperatures

Affected materials

Graphitisation

800°F~1100°F for C Steel

Plain carbon steel

875°F for C ½ Mo Steel

C, C ½ Mo

Spheroidisation

850 °F ~ 1400 °F

Low alloy steel up to 9% Cr

Tempered Embrittlement

650 °F~ 1070 °F

2 ¼ Cr-1Mo low alloy steel, 3Cr1Mo (lesser extent), & HSLA CrMo-V rotor steels

Strain Aging

Intermediate temperature

Pre-1980’s C-steels with a large grain size and C- ½ Mo

885°F embrittlement

600 °F~ 1000 °F

300, 400 & Duplex SS containing ferrite phases

Sigma-Phase Embrittlement

1000 °F~ 1700 °F

Ferritic, austenitic & duplex SS. Sigma forms most rapidly from the ferrite phase that exists in 300 Series SS and duplex SS weld deposits. It can also form in the 300 Series SS base metal (austenite phase) but usually more slowly.

Exam

Damage Mechanism

510/570 Brittle Fracture

Temperatures

Affected materials

Below DTBTT

C, C- ½ Mo, 400 SS

Creep & stress rupture 700 °F ~ 1000 °F 510/570 Thermal fatigues

All metals and alloys

Operating temperature

All materials of construction

Short Term Overheating – Stress Rupture

>1000 °F

All fired heater tube materials and common materials of construction

Steam Blanketing

>1000 °F

Carbon steel and low alloy steels

Dissimilar Metal Weld (DMW) Cracking

Operating temperature

Carbon steel / 300 SS junction

Thermal Shock

Cold liquid impinge on hot surface

All metals and alloys.

Exam

Damage Mechanism

Temperatures

Affected materials

Service temperature

All

Service temperature

All

570/510 Mechanical fatigue

Service temperature

All

570

Vibration-Induced Fatigue

Service temperature

All

Refractory Degradation

Service temperature

All

Reheat Cracking

Service temperature

CS, 300SS, Ni Based

GOX enhances combustion

Service temperature

All

570/510 Erosion/Erosion Corrosion Cavitation

4.2.1 Graphitization 石墨化 (不是API510/570考试项)

Prolong Exposure 800°F ~ 1100°F for C Steel >875°F for C ½ Mo Steel

4.2.1 Graphitization 石墨化 4.2.1.1 Description of Damage a) Graphitization is a change in the microstructure of certain carbon steels and 0.5Mo steels after long-term operation in the 800°F to 1100°F (427°C to 593°C) range that may cause a loss in strength, ductility, and/or creep resistance.在800°F 1100°F长期运行后 b) At elevated temperatures, the carbide phases in these steels are unstable and may decompose into graphite nodules. This decomposition is known as graphitization.碳钢/C - ½ Mo钢, 在长期受到高温度影响，钢中碳化物相变得不稳定, 从而分解成石墨结节 4.2.1.2 Affected Materials Some grades of carbon steel and 0.5Mo steels. (普通碳钢/0.5钼钢)

碳钢/C - ½ Mo钢, 在长期受到高温度影响，钢中碳化物相变得不稳定, 从而分解成石墨结节

Graphitization Location: Areas with tubes containing carbon steel and C-Mo. Most likely in the weld heat-affected zones and high residual stress areas. 易受影响区: 碳钢或 C- ½ Mo 普通碳钢, 焊接热影响区和高残余应力区

Probable cause: Prolonged exposure to above 800°F (425°C) for carbon steels and greater than 875°F (470°C) for the carbon- ½ molybdenum alloys. In graphitized boiler components, the nucleation of graphite likely starts by the precipitation of “carbon” from super-saturated ferrite, an aging phenomenon. This nucleation is enhanced by strain, in effect a strain aging. The preferential formation of graphite within the heat-affected zone is dependent on the balance of the structure being nearly strain free. Thus the “more unstable” heat-affected zone microstructure will decompose into ferrite and graphite before the annealed ferrite and pearlite of the normalized structure will. If the base metal is coldworked, the annealing of the weld will slow the nucleation of graphite, and the strained tube will graphitize before the heat-affected zone. 在长时间的高温影响下,蝶状珠光体(碳化铁)首先转化为粒状珠光体,然后碳从超饱和的碳化铁析出,晶核形成石墨与周边缺碳纯铁素体.

4.2.1.3 Critical Factors a) The most important factors that affect graphitization are the chemistry, stress, temperature, and time of exposure. b) In general, graphitization is not commonly observed. Some steels are much more susceptible to graphitization than others, but exactly what causes some steels to graphitize while others are resistant is not well understood. It was originally thought that silicon and aluminum content played a major role but it has been shown that they have negligible influence on graphitization. c) Graphitization has been found in low alloy C-Mo steels with up to 1% Mo. The addition of about 0.7% chromium has been found to eliminate graphitization. d) Temperature has an important effect on the rate of graphitization. Below 800째F (427째C), the rate is extremely slow. The rate increases with increasing temperature.

e) There are two general types of graphitization. First is random graphitization in which the graphite nodules are distributed randomly throughout the steel. While this type of graphitization may lower the room-temperature tensile strength, it does not usually lower the creep resistance.

f) The second and more damaging type of graphitization results in chains or local planes of concentrated graphite nodules. • Weld heat-affected zone graphitization is most frequently found in the heat-affected zone adjacent to welds in a narrow band, is called “eyebrow,” graphitization. • Non-weld graphitization is a form of localized graphitization that sometimes occurs along planes of localized yielding in steel. It also occurs in a chain-like manner in regions that have experienced significant plastic deformation as a result of cold working operations or bending.

Weld heat affected zone graphitization is most frequently found in the heat-affected zone adjacent to welds in a narrow band, corresponding to the low temperature edge of the heat affected zone. In multi-pass welded butt joints, these zones overlap each other, covering the entire cross-section. Graphite nodules can form at the low temperature edge of these heat affected zones, resulting in a band of weak graphite extending across the section. Because of its appearance, this graphite formation within heat affected zones is called â&#x20AC;&#x153;eyebrowâ&#x20AC;? graphitization.

Type 2: HAZ graphite nodules

eyebrow! Type2 Graphitization 焊缝热影响区石墨化现象

eyebrow! Graphitization

eyebrow! Type 2 Graphitization 焊缝热影响区现象

太厉害了,别人的肖像变成他家的版权了..NMD

Non-weld graphitization is a form of localized graphitization that sometimes occurs along planes of localized yielding in steel. It also occurs in a chain-like manner in regions that have experienced significant plastic deformation as a result of cold working operations or bending. 显著地塑性变形区域, 石墨化可能以链状方式形成.

Type 2: Non Weld Chains or local planes of concentrated graphite nodules

4.2.1.4 Affected Units or Equipment a) Primarily hot-wall piping and equipment in the FCC, catalytic reforming and coker units. b) Bainitic grades are less susceptible than coarse pearlitic grades. c) Few failures directly attributable to graphitization have been reported in the refining industry. However, graphitization has been found where failure resulted primarily from other causes. d) Several serious cases of graphitization have occurred in the reactors and piping of fluid catalytic cracking units, as well as with carbon steel furnace tubes in a thermal cracking unit and the failure of seal welds at the bottom tube sheet of a vertical waste heat boiler in a fluid catalytic cracker. A graphitization failure was reported in the long seam weld of a C 0.5Mo catalytic reformer reactor/inter-heater line.

e) Where concentrated eyebrow graphitization occurs along heat-affected zones, the creep rupture strength may be drastically lowered. Slight to moderate amounts of graphite along the heat-affected zones do not appear to significantly lower room or high-temperature properties. f) Graphitization seldom occurs on boiling surface tubing but did occur in low alloy C-0.5Mo tubes and headers during the 1940’s. Economizer tubing, steam piping and other equipment that operates in the range of temperatures of 850°F to 1025°F (441°C to 552°C) is more likely to suffer graphitization.

4.2.1.5 Appearance or Morphology of Damage 1. Damage due to graphitization is not visible or readily apparent and can only be observed by metallographic examination (Figure 4-1 and Figure 4-2). 2. Advanced stages of damage related to loss in creep strength may include micro-fissuring / microvoid formation, subsurface cracking or surface connected cracking.

0.5Îźm

Figure 4-1 â&#x20AC;&#x201C; High magnification photomicrograph of metallographic sample showing graphite nodules. Compare to normal microstructure shown in Figure 4-2.

Figure 4-2 â&#x20AC;&#x201C; High magnification photomicrograph of metallographic sample showing typical ferrite-pearlite structure of carbon steel.

4.2.1.6 Prevention / Mitigation 预防/缓解 Graphitization can be prevented by using chromium containing low alloy steels for long-term operation above 800°F (427°C).

The addition of about 0.7% chromium has been found to eliminate graphitization.

0.7% chromium

以消除石墨化.

4.2.1.7 Inspection and Monitoring a) Evidence of graphitization is most effectively evaluated through removal of full thickness samples for examination using metallographic techniques. Damage may occur mid-wall so that field replicas may be inadequate. b) Advanced stages of damage related to loss in strength include surface breaking cracks or creep deformation that may be difficult to detect. 4.2.1.8 Related Mechanisms Spheroidization (see 4.2.2) and graphitization are competing mechanisms that occur at overlapping temperature ranges. Spheroidization tends to occur preferentially above 1025째F (551째C), while graphitization predominates below this temperature.

Spheroidization (see 4.2.2) and graphitization are competing mechanisms that occur at overlapping temperature ranges. Spheroidization tends to occur preferentially above 1025째F (551째C), while graphitization predominates below this temperature. Graphitization can be prevented by using chromium containing low alloy steels for long-term operation above 800째F (427째C). Affected Materials: Some grades of carbon steel and 0.5Mo steels. Graphitization has been found in low alloy C-Mo steels with up to 1% Mo. The addition of about 0.7% chromium has been found to eliminate graphitization.

Creep Type: Microvoid formation & jointing of ligament between voids

Typical ferrite-pearlite structure of carbon steel.

Typical martensitic structure of carbon steel.

Figure 13: Lower bainite generated by isothermal transformation of 52100 steel at 230C for 10h http://www.msm.cam.ac.uk/phase-trans/2011/Bearings/index.htm l

Random graphitization

Chain graphitization http://davidnfrench.com/Graphitization.html

Graphitization of A Cast Iron Main

>800째F

石墨化,学习重点: 1. 高温现象: 800°F to 1100°F 2. 受影响材料: 碳钢(不包括低合金钢), ½ Mo钢 3. 损伤模式: (1) 无规则石墨化(仅仅影响室温抗拉)与 (2) HAZ/平面石墨化 (较为严厉,影响室温抗拉高温蠕变性能) 4. 注意项: ½ Mo钢,抗拒性较强,敏感温度为 875°F高于碳钢 800°F 5. 添加 0.7%Cr 有效阻止石墨化. 6. 不是API 510/570考试学习项.

http://www.chasealloys.co.uk/steel/alloying-elements-in-steel/#chromium

4.2.2 Carbide Spheroidization 碳化物球化 (不是API510/570考试项)

Spheroidization Prolong Exposure 850째F ~ 1400째F

4.2.2 Softening (Spheroidization) 碳化物球化 4.2.2.1 Description of Damage Spheroidization is a change in the microstructure of steels after exposure in the 850°F to 1400°F (440°C to 760°C) range, where the carbide phases 碳化物 in carbon steels are unstable and may agglomerate from their normal plate-like form to a spheroidal form, or from small, finely dispersed carbides in low alloy steels like 1Cr-0.5Mo to large agglomerated carbides. Spheroidization may cause a loss in strength and/or creep resistance. 4.2.2.2 Affected Materials All commonly used grades of carbon steel and low alloy steels including C0.5Mo, 1Cr-0.5Mo,1.25Cr-0.5Mo, 2.25Cr-1Mo, 3Cr -1Mo, 5Cr-0.5Mo, and 9Cr1Mo steels. 高温现象: 在长期高温下,细分散或板状碳化物形成球状形式. 涵盖了普通碳钢, 0.5Mo钢, 低合金钢,

Figure 9: The microstructures near the OD surface were mostly decarburized. The remaining carbides were highly spheroidized and agglomerated along the ferrite grain boundaries. The microstructure 90째 from the rupture and at the tube end is shown.(Nital etch, Mag. 500X)

Figure 10: The microstructures near the ID surface consisted of partially and highly spheroidized and agglomerated carbides along the ferrite grain boundaries. The microstructure 90째 from the rupture and at the tube end is shown. (Nital etch, Mag. 500X)

http://www.met-tech.com/short-term-overheat-rupture-of-t11-superheater-tube.html

Differences  Softening (Spheroidization), at prolong exposure to high temperature carbide phases in carbon steels are unstable and may agglomerate from their normal plate-like form to a spheroidal form, or from small, finely dispersed carbides in low alloy steels like 1Cr-0.5Mo to large agglomerated carbides. 在长期高温工作下,低合金碳钢,碳化物相变得不稳定, 导致正常板状形式凝聚成一个球状形式.  Graphitisation, the carbide phases in carbon/Molydenum steels are unstable and may decompose into graphite nodules.在高温长期工作下,普通碳钢/0.5钼钢中的化物相变得不稳定,这碳化物分解成石墨结节. 影响的材料差别为; (1) 普通碳钢/受石墨化影响 (2) 低合金含铬钼高强度,高温钢受碳化物球化

Spheroidization 球化 in physical metallurgy, a process consisting in the transition of excess-phase crystals into a globular (spheroidal) form. The transition occurs at relatively high temperatures and is associated with a decrease in the interfacial energy 高温下界面的能量减少. Of particular importance is the spheroidization of the cementite plates contained in pearlite. In this process, the lamellar pearlite is converted into granular pearlite片状珠光体转变为粒状珠光体. As a result, the hardness and the strength of the metal are significantly decreased, but the ductility is increased.

Carbide Spheroidization 碳化物球化

Figure 1. Corroded sheath exterior (0.85X Original Magnification)

Figure 2. Etched sample of a section of non-corroded material (200X Original Magnification with Nital Etch)

http://www.matter.org.uk/steelmatter/forming/4_5.html

 Graphitisation and spheroidization both were high temperature phenomenon.石墨化与球化都是材料高温效应  Graphitisation affect normal carbon steel. It is a break down of carbides into ferrite and free graphite (carbon) nodules.石墨化是高温下,碳化物分解为铁素体和游离石墨/碳.  Spheroidization affect Cr-Mo low carbon steel up to 9%Cr. It is a agglomeration of carbides forming spheroidal carbides. 球化是高温下,界面的能量减少导致片状珠光体转变为粒状珠光体

Spheroidization affect Cr-Mo low carbon steel up to 9% Cr. It is a agglomeration of carbides forming spheroidal carbides 影响达 9%Cr 低合金碳钢,高温下界面的能量减少,片状珠光体转变为粒状珠光体 (片状碳化物集聚形成球状碳化物).

含

9% Chromium

碳化物球化影响范围.

 Residual stress & cold works accelerated graphitization.残余应力和冷工程加速石墨化.  For spheroidisation coarse-grained steels are more resistant than fine-grained. Fine grained silicon-killed steels are more resistant than aluminum killed.  粗粒度的钢比细粒度更抗拒碳化物球化.  细晶硅镇静钢比铝镇静更抗拒碳化物球化.

Susceptibility to Spheroidization 球化易感性 • Annealed steels 退火钢材 are more resistant to spheroidization than normalized steels. • Coarse-grained steels 粗粒度钢材 are more resistant than fine-grained. • Fine grained silicon-killed steels are more resistant than aluminum-killed. • The loss in strength 强度损失 may be as high as about 30% but failure is not likely to occur except under very high applied stresses.

Exam

Temperatures

Affected materials

Graphitisation

800°F~1100°F for C Steel

Plain carbon steel

875°F for C ½ Mo Steel

C, C ½ Mo

 Some grades of carbon steel and 0.5Mo steels. NO

Spheroidisation 850°F ~ 1400°F

Low alloy steel up to 9% Cr.

All commonly used grades of carbon steel and low alloy steels including C-0.5Mo, 1Cr-0.5Mo,1.25Cr-0.5Mo, 2.25Cr-1Mo, 3Cr-1Mo, 5Cr-0.5Mo, and 9Cr-1Mo steels. Spheroidization (see 4.2.2) and graphitization are competing mechanisms that occur at overlapping temperature ranges. Spheroidization tends to occur preferentially above 1025°F (551°C), while graphitization predominates below this temperature. Discussion: Graphitization occurs on some carbon steel and 0.5Mo steels only.

Spheroidization is a change in the microstructure of steels after exposure in the 850°F to 1400°F (440°C to 760°C) range, where the carbide phases in carbon steels are unstable and may agglomerate from their normal plate-like form to a spheroidal form. 碳化物球化学习重点: 1. 高温现象 – 850°F to 1400°F, 2. 原理: 低合金碳钢,高温下界面的能量减少,片状珠光体转变为粒状珠光体 (片状碳化物集聚形成球状碳化物), 3. 受影响材质:涵盖了普通碳钢, 0.5Mo钢,低合金钢至 9Cr1Mo钢, 4. 粗粒度的钢比细粒度更抗拒碳化物球化, 5. 细晶硅镇静钢比铝镇静更抗拒碳化物球化, 6. 不同于石墨化,碳化物还是碳化物只不过高温下聚集成为球状, 7. 非API 510/570考试题非API 510/570考试题

API510-Exam

4.2.3 Temper Embrittlement 回火脆化

API510-Exam

650 F~ 1070 F

API510-Exam

Graphitization 石墨化

800°F~1100°F for C Steel Plain carbon steel / 0.5Mo Steel 875°F for C ½ Mo Steel

Spheroidization碳 850°F ~ 1400°F 化物球化 Tempered Embrittlement 回火脆化

650°F~ 1070°F

0.5Mo Steel, Low alloy steel up to 9 % Cr 2 ¼ Cr-1Mo low alloy steel, 3Cr-1Mo (lesser extent), & HSLA Cr-Mo-V rotor steels

API510-Exam

4.2.3 Temper Embrittlement 回火脆化 4.2.3.1 Description of Damage Temper embrittlement is the reduction in toughness due to a metallurgical change that can occur in some low alloy steels as a result of long term exposure in the temperature range of about 650°F to 1100°F (343°C to 593°C) . This change causes an upward shift in the ductile-to-brittle transition temperature as measured by Charpy impact testing. Although the loss of toughness is not evident at operating temperature, equipment that is temper embrittled may be susceptible to brittle fracture during start-up and shutdown. 2¼ Cr-1Mo ~ 3Cr-1Mo量低合金钢在650°F to 1100°F工作下,导致受影响材质, 韧脆转变温度向上移位. 工作状态下,设备不会受到此损伤机理任何影响,但在关机,重启时的低温下,材料会因回火脆性的损伤机理导致产生设备受压母材脆裂.

API510-Exam

Temper embrittlement is the reduction in toughness due to a metallurgical change that can occur in some low alloy steels as a result of long term exposure in the temperature range of about 650°F to 1100°F (343°C to 593°C) . 2¼ Cr-1Mo~ 3Cr-1Mo钢材在650°F to 1100°F 工作下,导致受影响材质, 韧脆转变温度向上移位.

API510-Exam

4.2.3.2 Affected Materials a) Primarily 2 ¼ Cr-1Mo (P5A) low alloy steel, 3Cr-1Mo (P5A) (to a lesser extent), and the high-strength low alloy Cr-Mo-V (P5C) rotor steels. b) Older generation 2 ¼ Cr-1Mo materials manufactured prior to 1972 may be particularly susceptible. Some high strength low alloy steels are also susceptible. c) The C- ½ Mo (P3) and 1 ¼ Cr- ½ Mo (P4) alloy steels are not significantly affected by temper embrittlement. However, other high temperature damage mechanisms promote metallurgical changes that can alter the toughness or high temperature ductility of these materials. 主要是对 2¼ Cr-1Mo~ 3Cr-1Mo低合金钢, Cr-Mo-V轴钢受影响.

API510-Exam

Temper Embrittlement 回火脆性易感性

3Cr-1Mo (to a lesser extent)

Primarily 2.25Cr-1Mo low alloy steel. and the highstrength low alloy Cr-Mo-V rotor steels.

The C-0.5Mo, 1Cr0.5Mo and 1.25Cr0.5Mo alloy steels are not significantly affected.

API510-Exam

[Embrittlement temperature 650째F~1070째F]

API510-Exam

[Embrittlement temperature 650째F~1070째F]

API510-Exam

[Embrittlement temperature 650째F~1070째F]

API510-Exam

韧脆转变温度

API510-Exam

韧脆转变温度向上移位

API510-Exam

脆性转变温度向上移位.另个特征是回火脆化,不会对脆性转变点上搁架冲击功有任何影响.

API510-Exam

SEM fractographs of tempered embrittled material show primarily intergranular cracking due to impurity segregation at grain boundaries 材料的回火脆化,主要是由于晶界杂质偏聚导致是沿晶开裂

API510-Exam

http://www.twi.co.uk/news-events/bulletin/archive/1999/januaryfebruary/welding-and-fabrication-of-high-temperature-components-foradvanced-power-plant-part-1/

API510-Exam

4.2.3.3 Critical Factors 关键因素 a) Alloy steel composition, thermal history, metal temperature and exposure time are critical factors. 受热历史,金属温度和受感时间是关键因素 b) Susceptibility to temper embrittlement is largely determined by the presence of the alloying elements manganese and silicon, and the tramp elements phosphorus, tin, antimony, and arsenic. The strength level and heat treatment/fabrication history should also be considered. 回火脆化敏感性很大程度上决定于锰/硅与杂元素(磷/锡/锑和砷)含量. c) Temper embrittlement of 2.25Cr-1Mo steels develops more quickly at 900°F (482°C) than in the 800°F to 850°F (427°C to 440°C) range, but the damage is more severe after long-term exposure at 850°F (440°C). 高温下易感性较大,但在低温下伤害较为严重.

API510-Exam

d) Some embrittlement can occur during fabrication heat treatments, but most of the damage occurs over many years of service in the embrittling temperature range. 有的损伤是因建造热处理引发,但一般上大多数受感于长期在敏感温度下操作引发的. e) This form of damage will significantly reduce the structural integrity of a component containing a crack-like flaw. An evaluation of the materials toughness may be required depending on the flaw type, the severity of the environment, and the operating conditions, particularly in hydrogen service. 含裂纹状缺陷的部件会减弱结构完整性. 特别是氢服务设备,应在考虑缺陷的类型, 处理工艺的严峻性与操作条件,进行材料的韧性评估.

API510-Exam

4.2.3.4 Affected Units or Equipment a) Temper embrittlement occurs in a variety of process units after long term exposure to temperatures above 650°F (343°C). It should be noted that there have been very few industry failures related directly to temper embrittlement. b) Equipment susceptible to temper embrittlement is most often found in hydroprocessing units, particularly reactors, hot feed/effluent exchanger components, and hot HP separators. Other units with the potential for temper embrittlement include catalytic reforming units (reactors and exchangers), FCC reactors, coker and visbreaking units. c) Welds in these alloys are often more susceptible than the base metal and should be evaluated. 受影响的设备主要是用于高温处理单元,例如加氢装置,催化重整装置,催化裂化反应器,炼焦器,减粘裂化单元,等. 焊接部位受感性比母材强,这位应当作为评估考虑部位.

API510-Exam

http://www.twi-global.com/technical-knowledge/job-knowledge/defectsimperfections-in-welds-reheat-cracking-048/ http://en.wikipedia.org/wiki/Welding_defect

API510-Exam

4.2.3.5 Appearance or Morphology of Damage a) Temper embrittlement is a metallurgical change that is not readily apparent and can be confirmed through impact testing. Damage due to temper embrittlement may result in catastrophic brittle fracture. 外观变化不明显,需要通过冲击试验证实. b) Temper embrittlement can be identified by an upward shift in the ductile-tobrittle transition temperature measured in a Charpy V-notch impact test, as compared to the non-embrittled or de-embrittled material (Figure 4-5). Another important characteristic of temper embrittlement is that there is no effect on the upper shelf energy.夏比V型缺口冲击试验证实韧性- 脆性转变温度向上移位.另个特征是回火脆化,不会对脆性转变点上搁架冲击功有任何影响. c) SEM fractographs of severely temper embrittled material show primarily intergranular cracking due to impurity segregation at grain boundaries. 主要为晶间开裂

API510-Exam

Intergranular Cracking

API510-Exam

Intergranular Cracking Metal surface Cr5C2/ Cr3C2 precipitated Low Cr grain boundary Crack initiation & growth

Progressive crack

API510-Exam

Embrittlement Mechanism

Tensile stress

Grain Boundary Cr depleted grain boundary PPT as Cr5C2/Cr3C2

Grain boundary decohesionCrack initiation pt.

API510-Exam

4.2.3.6 Prevention / Mitigation a) Existing Materials 1. Temper embrittlement cannot be prevented if the material contains critical levels of the embrittling impurity elements and is exposed in the embrittling temperature range. 2. To minimize the possibility of brittle fracture during startup and shutdown, many refiners use a pressurization sequence to limit system pressure to about 25 percent of the maximum design pressure for temperatures below a Minimum Pressurization Temperature (MPT). Note that MPT is not a single point but rather a pressure temperature envelope which defines safe operating conditions to minimize the likelihood of brittle fracture.

API510-Exam

3. MPT’s generally range from 350°F (171°C) for the earliest, most highly temper embrittled steels, down to 125°F (52°C) or lower for newer, temper embrittlement resistant steels (as required to also minimize effects of hydrogen embrittlement). 4. If weld repairs are required, the effects of temper embrittlement can be temporarily reversed (de-embrittled) by heating at 1150°F (620°C) [compared: embrittlement temperature 650°F~1070°F] for two hours per inch of thickness, and rapidly cooling to room temperature. It is important to note that re-embrittlement will occur over time if the material is re-exposed to the embrittling temperature range.

API510-Exam

Existing Material: De-embrittlement treatment.

Heating at 1150°F (620°C) [compared: embrittlement temperature 650°F~1070°F (343°C to 593°C) ] for two hours per inch of thickness, and rapidly cooling to room temperature.

API510-Exam

b) New Materials The best way to minimize the likelihood and extent of temper embrittlement is to limit the acceptance levels of manganese, silicon, phosphorus, tin, antimony, and arsenic in the base metal and welding consumables. In addition, strength levels and PWHT procedures should be specified and carefully controlled. 最好的缓解方法是控制母材/焊材的锰,硅,磷,锡,锑,砷的成分.

Acceptance Level of Mn, Si, P, Sn, Sb, As.

API510-Exam

Susceptibility to temper embrittlement A common way to minimize temper embrittlement is to limit the "J*" Factor for base metal and the "X" Factor for weld metal, based on material composition as follows: J* = (Si + Mn) x (P + Sn) x 104 {elements in wt%} X = (10P + 5Sb + 4Sn + As)/100 {elements in ppm}

API510-Exam

Typical J* and X factors used for 2.25 Cr steel are a maximum of 100 and 15, respectively. Studies have also shown that limiting the (P + Sn) to less than 0.01% is sufficient to minimize temper embrittlement because (Si + Mn) control the rate of embrittlement.

J* : 100 Max. (Base metal) X : 15 Max. (Weld metal)

API510-Exam

4.2.3.7 Inspection and Monitoring a) a) A common method of monitoring is to install blocks of original heats of the alloy steel material inside the reactor. Samples are periodically removed from these blocks for impact testing to monitor/establish the ductile-brittle transition temperature. The test blocks should be strategically located near the top and bottom of the reactor to make sure that the test material is exposed to both inlet and outlet conditions. b) Process conditions should be monitored to ensure that a proper pressurization sequence is followed to help prevent brittle fracture due to temper embrittlement. 4.2.3.8 Related Mechanisms Not applicable.

API510-Exam

Figure 4-5 â&#x20AC;&#x201C; Plot of CVN toughness as a function of temperature showing a shift in the 40-ft-lb transition temperature.

API510-Exam

Temper embrittlement is inherent in many steels and can be characterized by reduced impact toughness. The state of temper embrittlement has practically no effect on other mechanical properties at room temperature. Figure 1 shows schematically the effect of temperature on impact toughness of alloy steel which is strongly liable to temper embrittlement. Many alloy steels have two temperature intervals of temper embrittlement. For instance, irreversible temper brittleness may appear within the interval of 250-400째C and reversible temper brittleness, within 450째C-650째C. http://www.keytometals.com/Articles/Art102.htm

API510-Exam

irreversible temper brittleness may appear within the interval of 250-400째C

reversible temper brittleness, within 450째C-650째C.

API510-Exam

Metallurgy of Mo in alloy steel & iron Temper embrittlement may occur when steels are slowly cooled after tempering through the temperature range between 450 and 550°C. This is due to the segregation of impurities such as phosphorus, arsenic, antimony and tin on the grain boundaries. The molybdenum atom is very large relative to other alloying elements and impurities. It effectively impedes the migration of those elements and thereby provides resistance to temper embrittlement. http://www.imoa.info/molybdenum_uses/moly_grade_alloy_steels_irons/tempering.php Other/ 其他阅读 Other reference: http://www.twi.co.uk/technical-knowledge/faqs/material-faqs/faq-what-is-temperembrittlement-and-how-can-it-be-controlled/

回火脆化学习重点: 1. 高温现象: 650°F to 1100°F, 2. 原理: 材料的回火脆化,主要是由于晶界杂质偏聚导致是沿晶开裂 3. 受影响材质:, 2.25Cr1Mo ~ 3Cr1Mo低合金钢与轴钢,不涵盖普通碳钢, 4. 最好的缓解方法是控制母材/焊材的锰,硅,磷,锡,锑,砷的成分, 5. 其他缓解方法: 控制材料强度(?)与热处理受感温度, 6. 这种脆化现象不能在高于受感温度热处理逆转恢复. 7. 除了低温冲击功,不影响其他高低温机械性能.

4.2.4 Strain Aging 时效伸张 (不是API510/570考试项)

Intermediate temperature

Graphitisation

800°F for C Steel

Plain carbon steel

875°F for C ½ Mo Steel Spheroidization

850oF ~ 1400oF

Plain carbon + Low alloy steel up to 9% Cr

Tempered Embrittlement

650°F~ 1070°F

2 ¼ Cr-1Mo low alloy steel, 3Cr1Mo (lesser extent), & HSLA Cr-Mo-V rotor steels

Strain Aging

Intermediate temperature

pre-1980’s carbon steels with a large grain size and C-0.5 Mo

885oF embrittlement

600°F~ 1000°F

300, 400 & Duplex SS containing ferrite phases

受影响的材质是那些老工艺的炼钢方法的普通碳钢与 0.5Mo钢 – 含有高成分的关键杂质元素与粗晶粒.

4.2.4 Strain Aging 伸张时效 4.2.4.1 Description of Damage Strain aging is a form of damage found mostly in older vintage carbon steels and C-0.5 Mo low alloy steels under the combined effects of deformation and aging at an intermediate temperature. This results in an increase in hardness and strength with a reduction in ductility and toughness. 4.2.4.2 Affected Materials Mostly older (pre-1980’s) carbon steels with a large grain size and C-0.5 Mo low alloy steel. When susceptible materials are plastically deformed and exposed to intermediate temperatures, the zone of deformed material may become hardened and less ductile. 一般上受影响的是1980年或更早前的碳钢(特别是大粒径 / C- ½ Mo), 当这些敏感的材料, 经过塑性变形和接触中间温度作业时，这变形材料区可能变硬和延展性与韧性降低。

Most of the effects of cold work on the strength and ductility of structural steels can be eliminated by thermal treatment, such as stress relieving, normalizing, or annealing. However, such treatment is not often necessary. 伸张时效对强度和韧性的影响能以热处理逆转恢复.

http://link.springer.com/article/10.1007%2Fs11668-006-5014-3#page-1 http://link.springer.com/article/10.1007%2FBF02715166#page-1 http://matperso.mines-paristech.fr/Donnees/data03/386-belotteau09.pdf

韧性减低/抗拉曾强

拉力 AISC- Guide to Design Criteria for Bolted and Riveted Joints

4.2.4.3 Critical Factors关键因素 a) Steel composition and manufacturing process determine steel susceptibility. b) Steels manufactured by the Bessemer or open hearth process contain higher levels of critical impurity elements than newer steels manufactured by the Basic Oxygen Furnace (BOF) process. c) In general, steels made by BOF and fully killed with aluminum will not be susceptible. The effect is found in rimmed and capped steels with higher levels of nitrogen and carbon, but not in the modern fully killed carbon steels manufactured to a fine grain practice. 受感性强材质:  含有高成分的关键杂质元素的转炉或平炉炼钢法(老炼钢法),  含大量的氢与碳元素的压盖钢/半镇静钢/沸腾钢不受影响材质:  碱性氧气转炉炼钢法, 铝镇静钢,细晶粒实践钢.

d) Strain aging effects are observed in materials that have been cold worked and placed into service at intermediate temperatures without stress relieving. 冷加工件(无热处理)用于中等温度服务. e) Strain aging is a major concern for equipment that contains cracks. If susceptible materials are plastically deformed and exposed to intermediate temperatures, the zone of deformed material may become hardened and less ductile. This phenomenon has been associated with several vessels that have failed by brittle fracture. 塑性变材料当接触到中等温度时, 变形的区域会变硬与减少韧性,如这材料带裂缝时会导致设备脆性断裂. f) The pressurization sequence versus temperature is a critical issue to prevent brittle fracture of susceptible materials.加压顺序与温度是预防时效伸张开裂的关键方法. g) Strain aging can also occur when welding in the vicinity of cracks and notches in a susceptible material. 焊接加热也会加剧带裂纹的受感材料.

Bessemer Process

Open hearth Process

Open hearth Process 平炉炼钢法

Basic Oxygen Process 碱性氧气转炉炼钢法

Basic Oxygen Process

Metallurgy for Dummies http://metallurgyfordummies.com/steelmaking-technology/

Capped Steel半镇静钢,加盖钢:  It has characteristics similar to those of rimmed steels but to a degree intermediate between those of rimmed and semi-killed steels.  A deoxidizer may be added to effect a controlled running action when the steel is cast. the gas entrapped during solidification is in excess of that needed to counteract normal shrinkage, resulting in a tendency for the steel to rise in the mould.  The capping operation caused the steel to solidify faster, thereby limiting the time of gas evolution, and prevents the formation of an excessive number of gas voids within the ingot.  Capped steel is generally cast in bottle-top moulds using a heavy metal cap.  Capped steel may also be cast in open-top moulds, by adding aluminum or ferro-silicon on the top of molten steel, to cause the steel on the surface to lie quietly and solidify rapidly.

4) Rimmed Steel 沸腾钢,不脱氧钢:  In rimmed steel, the aim is to produce a clean surface low in carbon content. Rimmed steel is also known as drawing quality steel.  The typical structure results for a marked gas evolution during solidification of outer rim.  They exhibit greatest difference in chemical composition across sections and from top to bottom of the ingot.  They have an outer rim that is lower in carbon, phosphorus, and sulphur than the average composition of the whole ingot and an inner portion or core that is higher the average in those elements.  In rimming, the steel is partially deoxidized. Carbon content is less than 0.25% and manganese content is less than 0.6%.  They do not retain any significant percentage of highly oxidizable elements such as Aluminum, silicon or titanium.  A wide variety of steels for deep drawing is made by the rimming process, especially where ease of forming and surface finish are major considerations.  These steel are, therefore ideal for rolling, large number of applications, and is adapted to cold-bending, cold-forming and cold header applications.

应变时效学习重点: 1. 中等温度现象 – ?°F to ?°F, 2. 受感材质:含有高成分的关键杂质元素的转炉或平炉炼钢法,未经过热处理冷加工件.粗晶粒钢. 3. 受感设备: 高厚度非热处理受感材质设备. 4. 碱性氧气转炉炼钢法,铝镇静钢,细晶粒实践钢不受影响. 5. 蓝脆性为别名. 6. 非API 510/570考试题非API 510/570考试题

4.2.5 885°F (475°C) embrittlement 885°F 脆化-铁素体不锈钢/双相钢 (不是API510/570考试项)

885째F (475째C) embrittlement 600째F~ 1000째F

Graphitisation

800°F for C Steel

Plain carbon steel

875°F for C ½ Mo Steel Spheroidization

850oF ~ 1400oF

Plain carbon + Low alloy steel up to 9% Cr

Tempered Embrittlement

650°F~ 1070°F

2 ¼ Cr-1Mo low alloy steel, 3Cr1Mo (lesser extent), & HSLA Cr-Mo-V rotor steels

Strain Aging

Intermediate temperature

pre-1980’s carbon steels with a large grain size and C-0.5 Mo

885°F embrittlement

600°F~ 1000°F

300*, 400 & Duplex SS containing ferrite phases

受影响的材质:含铁素土的不锈钢. * 锻与铸件奥氏体不锈钢.

4.2.5 885°F (475°C) Embrittlement 4.2.5.1 Description of Damage  885°F (475°C) embrittlement is a loss in toughness due to a metallurgical change that can occur in stainless steel containing a ferrite phase, as a result of exposure in the temperature range 600°F~1000°F (316°C to 540°C). 4.2.5.2 Affected Materials a) 400 Series SS- ferritic & martensitic (e.g., 405, 409, 410, 410S, 430, and 446). b) Duplex stainless steels such as Alloys 2205, 2304, and 2507. c) Wrought and cast 300 Series SS containing ferrite, particularly welds and weld overlay. 高温现象: 600°F to 1000°F 含有铁素体相不锈钢 (铁素体/马氏体/双相/奥氏体-全包含)由于冶金的变化韧性的损失现象.

885°F (475°C) embrittlement Embrittlement of stainless steels containing ferrite phase upon extended exposure to temperatures between 730°F and 930°F (400°C and 510°C ). This type of embrittlement is caused by fine, chromium-rich precipitates that segregate at grain boundaries: time at temperature directly influences the amount of segregation. Grain-boundary segregation of the chromium-rich precipitates increases strength and hardness, decreases ductility and toughness, and changes corrosion resistance. This type of embrittlement can be reversed by heating above the precipitation range. 885°F 脆化,这种类型的脆化是由于富含铬的析出物在晶界处偏析出.晶界偏析的富含铬的析出增加强度和硬度,降低塑性和韧性和耐腐蚀变化(减弱).这种脆化现象能在高于析出温度热处理逆转恢复. http://www.keytometals.com/page.aspx?ID=CheckArticle&site=kts&LN=CN&NM=102

ď Ž Most refining companies limit the use of ferritic stainless steels to nonpressure boundary applications because of this damage mechanism. ď Ž 885Â°F embrittlement is a metallurgical change that is not readily apparent with metallography but can be confirmed through bend or impact testing (Figure 4-6).

 The existence of 885°F embrittlement can be identified by an increase in hardness in affected areas. Failure during bend testing or impact testing of samples removed from service is the most positive indicator of 885°F embrittlement.  885°F embrittlement is reversible by heat treatment to dissolve precipitates, followed by rapid cooling. The de-embrittling heat treatment temperature is typically 1100°F (593°C) or higher and may not be practical for many equipment items. If the de-embrittled component is exposed to the same service conditions it will re-embrittle faster than it did initially.

4.2.5.3 Critical Factors 关键因素 a) The alloy composition, particularly chromium content, amount of ferrite phase, and operating temperature are critical factors. 铬,铁素体相的数量和操作温度 b) Increasing amounts of ferrite phase increase susceptibility to damage when operating in the high temperature range of concern. A dramatic increase in the ductile-to-brittle transition temperature will occur. 越来越多的铁素体相的增加损伤的易感性(韧脆转变温度显著提高) c) A primary consideration is operating time at temperature within the critical temperature range. Damage is cumulative and results from the precipitation of an embrittling intermetallic phase that occurs most readily at approximately 885°F (475°C). Additional time is required to reach maximum embrittlement at temperatures above or below 885°F (475°C). For example, many thousands of hours may be required to cause embrittlement at 600°F (316°C). 损伤是因在受感温度操作时,金属间项 (intermetallic phase)的溢出/沉淀在晶间导致的.

d) Since 885°F embrittlement can occur in a relatively short period of time, it is often assumed that susceptible materials that have been exposed to temperatures in the 700°F to 1000°F (371°C to 538°C) range are affected. 受感温度一般上定义为700°F至1000°F 之间 e) The effect on toughness is not pronounced at the operating temperature, but is significant at lower temperatures experienced during plant shutdowns, startups or upsets.对韧性的影响体现在较低于操作温度例如在停机,启动和颠覆状态时. f) Embrittlement can result from tempering at higher temperatures or by holding within or cooling through the transformation range. 在受感温度回火热处理或当冷却时在受感(转变)温度停留会导致885°F脆化.

Fig. 2â&#x20AC;&#x201D;Microstructure of solution-annealed 304LN stainless steel

Fig. 3â&#x20AC;&#x201D;Oxalic acid etched microstructures of 304LN stainless steel sensitized for (a) 1 h, (b) 25 h, (c) 50 h, and (d) 100 h.

4.2.5.7 Inspection and Monitoring a) Impact or bend testing of samples removed from service is the most positive indicator of a problem. b) Most cases of embrittlement are found in the form of cracking during turnarounds, or during startup or shutdown when the material is below about 200째F (93째C) and the effects of embrittlement are most detrimental. c) An increase in hardness is another method of evaluating 885째F embrittlement.

Impact energy and brinell hardness as function of time exposure qt 475째C 475oC Embrittlement in a Duplex Stainless Steel UNS S31803

475oC Embrittlement in a Duplex Stainless Steel UNS S31803 http://www.scielo.br/scielo.php?pid=S1516-14392001000400003&script=sci_arttext

http://www.sciencedirect.com/science/article/pii/S0921509309000197

 885°F (475°C) Embrittlement of stainless steels in alloys containing a ferrite phase (Ferritic/Martensitic/Duplex stainless steel and ferrite phases in austenitic stainless steel e.g. weld areas) 影响材质: 含铁素体的不锈钢  Grain-boundary segregation of the chromium-rich precipitates increases strength and hardness, decreases ductility and toughness, and changes corrosion resistance (lower). 含富铬金属间 (intermetallic)在晶间溢出导致脆化.  This type of embrittlement can be reversed by heating above the precipitation range.可以通过加热逆转恢复  Impact testing/bend test & hardness testing used to evaluate susceptibility. 冲击试验,弯曲试验,硬度试验作为易感性的评估.  Restrict the used of ferritic steel to non-pressure boundary application. 限制铁素体不锈钢用于非受压用途.

4.2.6 Sigma-Phase Embrittlement “西格玛”相脆化 (不是API510/570考试项)

Sigma-Phase Embrittlement 1000oF~1700oF

885°F embrittlement

600°F~ 1000°F

300*, 400 & Duplex SS containing ferrite phase

Sigma phase embrittlement

1000°F~ 1700°F

300, 400 & Duplex SS containing ferrite phases

受影响的材质:含铁素体的不锈钢, * 锻与铸件奥氏体不锈钢

4.2.6 Sigma Phase Embrittlement 4.2.6.1 Description of Damage Formation of a metallurgical phase known as sigma phase can result in a loss of fracture toughness in some stainless steels as a result of high temperature exposure. 4.2.6.2 Affected Materials a) 300 Series SS wrought metals, weld metal, and castings. Cast 300 Series SS including the HK and HP alloys are especially susceptible to sigma formation because of their high (10-40%) ferrite content. b) The 400 Series SS and other ferritic and martensitic SS with 17% Cr or more are also susceptible (e.g., Types 430 and 440). c) Duplex stainless steels. 受影响的材质: 铁素体不锈钢,含铁素体的马氏体,奥氏体不锈钢和双相不锈钢. 脆化原因: 在受感温度下,西格玛相形成,在铁素体项析出导致脆化. http://www.hindawi.com/journals/isrn.metallurgy/2012/732471/

Sigma-Phase Embrittlement 西格玛相脆化 Description: Embrittlement of iron-chromium alloys caused by precipitation at grain boundaries of the hard, brittle intermetallic sigma phase σ during long periods of exposure to temperatures between approximately 565oC and 980oC (1050oF and 1800oF). Sigma phase embrittlement results in severe loss in toughness and ductility and can make the embrittled material structure susceptible to intergranular corrosion. 在长时间暴露在温度约 565oC ~ 980oC (1050oF ~ 1800oF)之间,硬而脆的金属间化合物(σ相)在铁素体晶界处析出, σ相脆化导致的韧性和延展性严重损失与导致易受晶间腐蚀. http://www.keytometals.com/page.aspx?ID=CheckArticle&site=kts&LN=CN&NM=102

4.2.6.3 Critical Factors 关键因素 a) Alloy composition, time and temperature are the critical factors. 化学成分, 时间, 温度都是关键因素. b) In susceptible alloys, the primary factor that affects sigma phase formation is the time of exposure at elevated temperature. 易感材料;时间与经历温度为主要因素. c) Sigma phase occurs in ferritic (Fe-Cr), martensitic (Fe-Cr), austenitic (FeCr-Ni) and duplex stainless steels when exposed to temperatures in the range of 1000°F to 1700°F (538°C to 927°C). Embrittlement can result by holding within or cooling through the transformation range. 铁素体,马氏体, 奥氏体,双相钢,当停留或冷却途径1000°F to 1700°F 温度时,产生σ相析出. d) Sigma forms most rapidly from the ferrite phase that exists in 300 Series SS and duplex SS weld deposits. It can also form in the 300 Series SS base metal (austenite phase) but usually more slowly. σ相以较快的速度在铁素体相析出,但也会在奥氏体项较慢的速度析出.

e) The 300 Series SS can exhibit about 10% to 15% sigma phase. Cast austenitic stainless steels can develop considerably more sigma. σ 相在奥氏体不锈钢以10%~15%表现出来,铸件可能还高. f) Formation of sigma phase in austenitic stainless steels can also occur in a few hours, as evidenced by the known tendency for sigma to form if an austenitic stainless steel is subjected to a post weld heat treatment at 1275°F (690°C). σ相在奥氏体的析出只需几个小时,这脆化趋向可以从1275°F焊接热处理后, 出现σ相的到证明. g) The tensile and yield strength of sigmatized stainless steels increases slightly compared with solution annealed material. This increase in strength is accompanied by a reduction in ductility (measured by percent elongation and reduction in area) and a slight increase in hardness. σ相脆化后,抗拉强度.硬度相比固溶退火材料略有增加, 同时,延展性与韧性减少.

ÎŁ(Ď&#x192;)phase in austenitic matrix http://www.intecho pen.com/books/met allurgy-advancesin-materials-andprocesses/homogeni zation-heattreatment-toreduce-the-failureof-heat-resistantsteel-castings

ÎŁ(Ď&#x192;)phase in austenitic matrix

h) Stainless steels with sigma can normally withstand normal operating stresses, but upon cooling to temperatures below about 500°F (260°C) may show a complete lack of fracture toughness as measured in a Charpy impact test. Laboratory tests of embrittled weld metal have shown a complete lack of fracture toughness below 1000°F (538°C) 一般上材料在正常操作温度时不受西格玛相脆化影响,但是当材料温度降至 500°F材料完全缺乏韧性(实验室导致完全缺乏韧性的温度可能高至1000°F). i) The metallurgical change is actually the precipitation of a hard, brittle intermetallic compound that can also render the material more susceptible to intergranular corrosion. The precipitation rate increases with increasing chromium and molybdenum content.缺乏韧性是因硬脆性金属间化合物沉淀在晶间.随着铬和钼含量提高,沉淀率相应加速.

σ相脆化- 缺乏韧性是因硬脆性金属间(intermetallic-sigma phase)化合物沉淀在晶间.随着铬和钼含量提高,沉淀率相应加速.

Cr% & Mo% 铬和钼含量增加

The precipitation rate increases σ 相析出增加

4.2.6.4 Affected Units or Equipment a) Common examples include stainless steel cyclones, piping ductwork and valves in high temperature FCC (fluidized catalytic cracking )Regenerator service. b) 300 Series SS weld overlays and tube-to-tubesheets attachment welds can be embrittled during PWHT treatment of the underlying CrMo base metal. c) Stainless steel heater tubes are susceptible and can be embrittled.

FCC (fluidized catalytic cracking ) Regenerator service

http://www.phxequip.com/plant.73/fluid-catalytic-cracker-unit.aspx

FCC (fluidized catalytic cracking ) Regenerator service

Stainless steel heater tubes

tube-to-tubesheets attachment

4.2.6.5 Appearance or Morphology of Damage 损伤外观形态 a) Sigma phase embrittlement is a metallurgical change that is not readily apparent, and can only be confirmed through metallographic examination and impact testing. (Tables 4-1 and 4-2)外观上不能体现损伤,只能依靠金相分析和冲击试验 b) Damage due to sigma phase embrittlement appears in the form of cracking, particularly at welds or in areas of high restraint. σ相脆化一般上以开裂的形态出现特别是在焊缝与高抑制区域. c) Tests performed on sigmatized 300 Series SS (304H) samples from FCC regenerator internals have shown that even with 10% sigma formation, the Charpy impact toughness was 39 ft-lbs (53 J) at 1200°F (649°C). 材料: 304H 敏化度: 10%σ相温度/冲击功: 649°C / 53J

设备:催化裂化再生器材料: 304H 敏化度: 10%σ相温度/冲击功: 649°C / 53J 新材料的机械性能: SPECIFICATION FOR HEAT-RESISTING CHROMIUM AND CHROMIUM-NICKEL STAINLESS STEEL PLATE, SHEET, AND STRIP FOR PRESSURE VESSELS ASTM SA-240

SPECIFICATION FOR HEAT-RESISTING CHROMIUM AND CHROMIUM-NICKEL STAINLESS STEEL PLATE, SHEET, AND STRIP FOR PRESSURE VESSELS ASTM SA-240

d) For the 10% sigmatized specimen, the values ranged from 0% ductility at room temperature to 100% at 1200°F (649°C). Thus, although the impact toughness is reduced at high temperature, the specimens broke in a 100% ductile fashion, indicating that the wrought material is still suitable at operating temperatures. See Figures 4-7 to 4-11.敏化材料的室温延展性或许降至为零.但在1200°F材料的延展性可能不受任何的影响. e) Cast austenitic stainless steels typically have high ferrite/sigma content (up to 40%) and may have very poor high temperature ductility.铸造奥氏体不锈钢敏化都可能高至40%的σ相,这导致很差的高温塑性/延展性.

Evaluation of Sigma Phase Embrittlement of a Stainless Steel 304H Fluid Catalyst Cracking Unit Regenerator Cyclone 不锈钢 304H催化裂化再生旋风器σ相脆化评价. Authors: Ali Y. Al-Kawaie and Abdelhak Kermad ABSTRACT Testing was performed on a 304H stainless steel sample removed from a Fluid Catalyst Cracking Unit (FCCU) regenerator cyclone after 25 years of service to check for sigma phase formation. Sigma phase is a nonmagnetic inter-metallic phase composed mainly of iron and chromium (FeCr), which forms in ferritic and austenitic stainless steels during exposure at the temperature range 1,050 °F to 1,800 °F (560 °C to 980 °C), causing loss of ductility and toughness. Cracking may also occur if the component was impact-loaded or excessively stressed during shutdown or maintenance work. This article discusses the effect of sigma phase embrittlement on the FCCU regenerator cyclone after extended high temperature service. http://www.saudiaramco.com/content/dam/Publications/Journa l%20of%20Technology/Spring2011/Art%2012%20%20JOT%20Internet.pdf

Table 3. Micro-hardness testing. Test load: 200 g, Calibration Block Hardness: 256 + 10 HV, Measured Hardness of the calibration block: 258 VHN.

Table 2. Impact testing (Test Method: ASTM E23)

Fig. 1. Cyclone sample, as received.

Fig. 2. Micrograph showing carburized layer at the outer (top) surface, 100x (As received).

Fig. 3. Micrograph showing the microstructure at the outer (top) surface, 100x (Heat treaded).

Note: solution annealing at 1,066 째C for four hours, followed by a water quench before testing.

Fig. 4. Micrograph showing sigma formation at the center of the sample. Estimated volume fraction 7%, 100x (As received).

Fig. 5. Micrograph showing the microstructure at the center of the heat treated sample, 100x (Heat treated).

Note: solution annealing at 1,066 째C for four hours, followed by a water quench before testing.

Fig. 6. Micrograph showing sigma phase at the inner (bottom) surface of the original sample, 100x (As received).

Fig. 7. Micrograph showing the microstructure at the inner surface of the heat treated sample, 100x (Heat treated).

Note: solution annealing at 1,066 째C for four hours, followed by a water quench before testing.

Fig. 8a. SEM fractography showing the brittle fracture surface (Top - As received)

Fig. 8b. SEM fractography showing the ductile fracture (Bottom - Heat treated) of the impact tested samples.

4.2.6.6 Prevention / Mitigation a) The best way to prevent sigma phase embrittlement is to use alloys that are resistant to sigma formation or to avoid exposing the material to the embrittling range. 最好的预防方法是不用易敏材料与避免使材料暴露在脆化温度范围作业(这牵涉到设定合适的IOW) b) The lack of fracture ductility at room temperature indicates that care should be taken to avoid application of high stresses to sigmatized materials during shutdown, as a brittle fracture could result. 室温断裂韧性不足是σ相脆化损伤机理的特点. 这显著地影响设备在启动,关断与瞬态状态的使用; 在设备处于低温状态时避免设备受到高应力(设备随着温度提高增加设备受压).* c) The 300 Series SS can be de-sigmatized by solution annealing at 1950°F (1066°C) for four hours followed by a water quench. However, this is not practical for most equipment. σ相脆化损伤可以可以通过加热逆转恢复(温度 1950°F固溶退火). 然而这往往并不是在役设备实用的修护方案. Note* 注意设备压力试验时可能导致低温脆裂的危险.

d) Sigma phase in welds can be minimized by controlling ferrite in the range of 5% to 9% for Type 347 and somewhat less ferrite for Type 304. The weld metal ferrite content should be limited to the stated maximum to minimize sigma formation during service or fabrication, and must meet the stated minimum in order to minimize hot short cracking during welding. 奥氏体不锈钢铁素体含量的控制用于减少σ相脆化的形成. e) For stainless steel weld overlay clad Cr-Mo components, the exposure time to PWHT temperatures should be limited wherever possible.铬钼覆盖层焊后热处理尽量减少暴露时间.

What causes knife-line attack? For stabilized stainless steels and alloys, carbon is bonded with stabilizers (TiC or NbC) and no weld decay occurs in the heat affected zone during welding. In the event of a subsequent heat treatment or welding (above 1200oC), however, first the TiC / NbC may dissociated into free Ti, Nb and C, on cooling precipitation of chromium carbide Cr23C6 is possible and this leaves the narrow band adjacent to the fusion line susceptible to intergranular corrosion.

What causes weld decay? As in the case of intergranular corrosion, grain boundary precipitation, notably chromium carbides in non-stabilized stainless steels, is a well recognized and accepted mechanism of weld decay. In this case, the precipitation of chromium carbides is induced by the welding operation when the heat affected zone (HAZ) experiences a particular temperature range (550oC~850oC). The precipitation of chromium carbides consumed the alloying element - chromium from a narrow band along the grain boundary and this makes the zone anodic to the unaffected grains. The chromium depleted zone becomes the preferential path for corrosion attack or crack propagation if under tensile stress.

Anodic site

4.2.6.7 Inspection and Monitoring 检验与监测 a) Physical testing of samples removed from service is the most positive indicator of a problem. 设备采样机械试验时最好的方法确认损伤机制. b) Most cases of embrittlement are found in the form of cracking in both wrought and cast (welded) metals during turnarounds, or during startup or shutdown when the material is below about 500°F (260°C) and the effects of embrittlement are most pronounced. σ相脆化开裂失效模式一般出现于设备温度处于低于500°F (260°C) 状态例如当设备周转,启动,关断时. 4.2.6.8 Related Mechanisms 相关机制 Not applicable.不适用

Figure 10: Shaeffler diagram showing the embrittlement region of theﾏパhase [33]. http://www.hindawi.com/journals/isrn.metallurgy/2012/732471/

http://www.metalconsult.com/failure-analysis-furnace-tubes.html

http://www.metallograf.de/start-eng.htm?/untersuchungen-eng/sigmaphase/sigmaphase.htm

http://www.industrialheating.com/articles/90371-sigma-phase-embrittlement http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1517-70762009000300017

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1517-70762009000300017

Table 4: Chemical composition of ferrite austenite and sigma phases at 900oC

Polishing markings

Improperly etched specimen showing little or no sign of sigma phase

NaOH etched

Oxalic acid etchedDuplex SS

Sigma-phase embrittlement  高温现象:1000oF~1700oF  影响材质:铁铬合金  原理:σ相脆化损伤机理: 是当铁铬合金暴露在高温下, 硬,脆性的σ相金属间化合物晶界沉淀引起的脆性现象.  解决方法: σ相脆化损伤可以可以通过加热逆转恢复(温度1950°F固溶退火). 然而这往往并不是在役设备实用的修护方案.  非 API 510/570考试项

API510/570-Exam

4.2.7 Brittle Fracture 脆性破裂 API 510/570考试学习科目

API510/570-Exam

Brittle Fracture Below DTBTT DTBT: Ductile to brittle transition temperature.

API510/570-Exam

No shear lip, little micro void coalescence, little deformation

API510/570-Exam

4.2.7 Brittle Fracture 脆性断裂 4.2.7.1 Description of Damage 损伤描述 Brittle fracture is the sudden rapid fracture under stress (residual or applied) where the material exhibits little or no evidence of ductility or plastic deformation. 脆性断裂- 在应力(残余或应用)作用下突然快速断裂.材料表现出很少的延展性, 塑性变形. 4.2.7.2 Affected Materials 受影响材质 Carbon steels and low alloy steels are of prime concern, particularly older steels. 400 Series SS are also susceptible. 受影响的材质有; 碳钢, 低合金钢与铁素体/马氏体不锈钢 Affected Materials Ferritic/Martensitic STEELS 只对铁素体/马氏体钢材影响

API510/570-Exam

4.2.7.3 Critical Factors 关键因素 a) When the critical combination of three factors is reached, brittle fracture can occur: 1. The materials’ fracture toughness (resistance to crack like flaws) as measured in a Charpy impact test;断裂韧性 2. The size, shape and stress concentration effect of a flaw; 应力的形状与大小 3. The amount of residual and applied stresses on the flaw. 残余或外加应力 b) Susceptibility to brittle fracture may be increased by the presence of embrittling phases. 晶体脆化相存在会增加脆裂易感性 c) Steel cleanliness and grain size have a significant influence on toughness and resistance to brittle fracture.钢的纯净度和晶粒大小显著地影响材料韧性和断裂抗拒能力.

API510/570-Exam

d) Thicker material sections also have a lower resistance to brittle fracture due to higher constraint which increases triaxial stresses at the crack tip. 较厚的材料因更高的应力约束,增加了在裂纹尖端的三轴应力;导致较低的断裂阻力 d) In most cases, brittle fracture occurs only at temperatures below the Charpy impact transition temperature (or ductile-to-brittle transition temperature), the point at which the toughness of the material drops off sharply. 一般上脆裂发生在低于韧脆转变温度.

API510/570-Exam

Definition of Brittle Fracture 脆性断裂定义 a steel member may experience a brittle fracture. Three basic factors contribute to a brittle-cleavage type of fracture. They are; • • •

a triaxial state of stress, a low temperature, and a high strain rate or rapid rate of loading.

All these factors need not be present. Crack often propagates by cleavage – breaking of atomic bonds along specific crystallographic planes (cleavage planes), propagate rapidly without further increase in applied stress (applied or residual) with little indication of plastic deformation. In contrast, a ductile fracture occurs mainly by shear, usually preceded by considerable plastic deformation.

API510/570-Exam

Figure 7: The fracture examination using a SEM on C1 and C2 revealed features typical of transgranular fracture (left and middle) and signatures of intergranular cracking (left and right). The presence of both intergranular and transgranular features indicates a mixed-mode fracture morphology. http://www.drillingcontractor.org/tubular-fracturing-pinpointing-the-cause-14544

API510/570-Exam

In Case 2 from Oklahoma, the pin connection twisted off while making up the pin connection of a saver sub. http://www.drillingcontractor.org/tubular-fracturing-pinpointing-the-cause-14544

API510/570-Exam

Figure 4: The fracture on the Case 1 sub showed a grainy texture and â&#x20AC;&#x153;chevron marksâ&#x20AC;? that point toward the initiation site, which is typical morphology for brittle cracking

API510/570-Exam

Figure 5: The fracture on C3 exhibited a small fatigue region that was followed by brittle fracture. The fracture surface had a grainy appearance and presented a minuscule shear lip, which is also typical of a brittle fracture

API510/570-Exam

Various stages during ductile fracture 韧性断裂 are schematically shown in above figure. (a) Necking, 缩颈 (b) Cavity formation (microvoid), 微孔形成 (c) Cavity coalescence to form a crack (microvoid coalescence), 微孔的聚结 (d) Crack propagation, 裂缝蔓延 (e) Fracture (shear fracture). 断裂 (剪切断裂)

API510/570-Exam

Brittle fracture of a shaft caused by a small fatigue crack close to the keyway. The fatigue would be expected to start at the keyway root but actually began at a surface defect. http://www.surescreen.com/scientifics/library-of-failures.php

API510/570-Exam

http://www.wermac.org/misc/pressuretestingfailure2.html

API510/570-Exam

4.2.7.4 Affected Units or Equipment 受影响的单元或设备 a) Equipment manufactured to the ASME Boiler and Pressure Vessel Code, Section VIII, Division 1, prior to the December 1987 Addenda, were made with limited restrictions on notch toughness for vessels operating at cold temperatures. However, this does not mean that all vessels fabricated prior to this date will be subject to brittle fracture. Many designers specified supplemental impact tests on equipment that was intended to be in cold service. ASME锅炉和压力容器规范1987年12月前,因为对低温操作设备缺乏材料韧性要求的限制,这些设备可能有脆裂的隐患. 然而虽然不是规范要求,有的设计会因设备低温操作,对材质附加低温冲击要求. b) Equipment made to the same code after this date were subject to the requirements of UCS 66 (impact exemption curves). 引用ASME VIII DIV1 UCS 66 对材料冲击要求宽松条款的设备.

API510/570-Exam

c) Most processes run at elevated temperature so the main concern is for brittle fracture during startup, shutdown, or hydrotest/tightness testing. Thick wall equipment on any unit should be considered. 在设备因周转,启动,停机时低温状态 d) Brittle fracture can also occur during an auto-refrigeration event in units processing light hydrocarbons such as methane, ethane/ethylene, propane/propylene, or butane. This includes alkylation units, olefin units and polymer plants (polyethylene and polypropylene). Storage bullets/spheres for light hydrocarbons may also be susceptible. 蒸发自动冷却服务. e) Brittle fracture can occur during ambient temperature hydrotesting due to high stresses and low toughness at the testing temperature. 室温试压时

UCS-66 MATERIALS.