1、Use of 9Cr-1Mo-V (Grade 91) Steel in the Oil Refining IndustryAPI TECHNICAL REPORT 938-B FIRST EDITION, JUNE 2008Use of 9Cr-1Mo-V (Grade 91) Steel in the Oil Refining IndustryDownstream SegmentAPI T ECHNICAL REPORT 938-B FIRST EDITION, JUNE 2008Special NotesAPI publications necessarily address probl
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9、rwise, without prior written permission from the publisher. Contact the Publisher, API Publishing Services, 1220 L Street, N.W., Washington, D.C. 20005.Copyright 2008 American Petroleum InstituteForewordThis recommended practice is under the jurisdiction of the API Subcommittee on Fiberglass and Pla
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16、L Street, N.W., Washington, D.C. 20005.Suggested revisions are invited and should be submitted to the Standards Department, API, 1220 L Street, NW, Washington, D.C. 20005, standardsapi.org.iiiContentsPage1 Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
17、. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12 Terms, Definitions, Acronyms, and Symbols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12.1 Terms and Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
18、. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12.2 Acronyms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12.3 Symbols. . . . . . . . . . . . . . . . . . . . . . . .
19、. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .33 Base Metal Chemical, Physical, Mechanical and Metallurgical Properties . . . . . . . . . . . . . . . . . . . . . . . .33.1 General. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
20、. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .33.2 Chemical Composition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .33.3 Physical Properties . . . . . . . . .
21、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .33.4 Metallurgical Properties. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .73.5 Mechanical Prop
22、erties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .144 Metallurgy and Environmental Related Failure Mechanisms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .214.1 Oxidation and Sulfidation Res
23、istance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .214.2 Wet Hydrogen Sulfide Cracking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .214.3 Hydrogen Attack Resistance. .
24、. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .224.4 Hydrogen Embrittlement, Hydrogen Diffusivity and Trapping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .224.5 Temper Embrittlement . . . . . . . . . . . . . .
25、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .224.6 Type IV Cracking. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .225 Material Requirements. . . .
26、. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .235.1 Base Metal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .235.2 Wel
27、ding Consumables. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .236 Fabrication and Welding Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .276.1 Gener
28、al Concerns. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .276.2 Cold Bending . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
29、 . . . . . . .276.3 Hot Bending . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .286.4 Welding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
30、 . . . . . . . . . . . . . . . . . . . . . . . .287 Examples of 9Cr-1Mo-V Applications and Refinery Experiences. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .367.1 Experiences. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
31、 . . . . . . . . . . . . . . . . . . .367.2 Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .36Bibliography. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
32、. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40Figures1 Thermal Conductivity. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .42 Mean Coefficient of Linear Expansion. . . . . . . . . . .
33、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .63 Modulus of Elasticity vs. Temperature. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .74 Deep Hardening Behavior of Grade 91 Steel. . . . . . . . . . . .
34、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .85 Effect of Ni + Mn on AC1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .96 CCT Diagram of Grade 91 Steel . . . . . . . . . . . . . . . . . . .
35、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .97 Typical Microstructure of T/P91 After Normalizing and Tempering . . . . . . . . . . . . . . . . . . . . . . . . . . . . .108 Grain Coarsening Behavior. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
36、 . . . . . . . . . . . . . . . . . . . . . . . . . . . .139 Typical Plot of Hardness vs. Tempering Temperature for Heat Rolled and Normalized Grade 91 Steel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1410 Yield (0.2 %) and Ult
37、imate Tensile Strengths vs. Temperature for Grade 91 Alloy Steel . . . . . . . . . . . .1511 Charpy Impact Energy vs. Temperature of Grade 91 Alloy Steel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1712 Stress Rupture Strength of Commercial Heats of N + T Grade 91 Alloy Steel at 593
38、 C (1100 F) . . . .2013 Comparison of Creep Rupture Strength of Grade 91 Steel Weldments to Base Metal . . . . . . . . . . . . .21vPage14 Hardness Profile of Grade 91 Weldment with Type IV Soft Zone . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2315 Effect of Oxygen Content on Toughne
39、ss for Selected Grade 91 Weldments . . . . . . . . . . . . . . . . . . . . .2616 Influence of PWHT Temperature on Toughness of Grade 91 Filler Metal . . . . . . . . . . . . . . . . . . . . . . . .3317 Influence of PWHT Temperature and Holding Time on Hardness of Grade 91 SMAW Weld Metal. . . .34Tabl
40、es1 Specifications and Code Cases for 9Cr-1Mo-V Steels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .42 Chemical Composition (Heat Analysis) of 9Cr-1Mo-V and 9Cr-1Mo Steels. . . . . . . . . . . . . . . . . . . . . . . .53 Physical Properties of T/P91 Alloy vs. Temp
41、erature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .64 Heat Treatment and Mechanical Properties of 9Cr-1Mo-V Steel and 9Cr-1Mo Steel . . . . . . . . . . . . . . .115 Temperature Limits for 9Cr-1Mo-V Steel per ASME Section VIII, Division 1 (Section II, Part D) .
42、 . . . . .166 Temperature Limits of 9Cr-1Mo-V Steel per Section VIII, Division 2 (Section II, Part D) . . . . . . . . . . . .167 Maximum Allowable Stress Values “S” in ASME Section VIII, Division 1, for 9Cr-1Mo-V Steel in Comparison with 2 1/4 Cr-1Mo-V, 2 1/4 Cr-1Mo 9Cr-1Mo Alloy Steels and 316H Sta
43、inless Steel . . . .188 Design Stress Intensity Values “Sm” in ASME Section III, Division 2, for 9Cr-1Mo-V Steel in Comparison with 2 1/4 Cr-1Mo, 2 1/4 Cr-1Mo-V, 9Cr-1Mo Steels and 316 H Stainless Steel . . . . . . . . 199 Creep Rupture of ASTM A213 Grade T91 Steel. . . . . . . . . . . . . . . . . .
44、 . . . . . . . . . . . . . . . . . . . . . . . . . . . .2010 Compositional Specifications of 9Cr-1Mo-V Steels Weld Consumables. . . . . . . . . . . . . . . . . . . . . . . . .2411 Dissimilar Welding Filler Metal Selection for 9Cr-1Mo-V Steels . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
45、 . . .3512 Guideline for PWHT Temperature for Dissimilar Metal Welds. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3513 Case Histories of Grade 91 Refinery Uses Reported in NACE REFIN-COR . . . . . . . . . . . . . . . . . . . . . .3714 Additional Case History for Using Grade P91/
46、T91 Steel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .38IntroductionAlloy steel 9Cr-1Mo-V was initially developed in the 1950s by the ORNL for the Clinch River Breeder Reactor. In 1974, a task force was initiated by the U.S. Department of Energy (DOE) to select materia
47、ls for the Liquid Metal Fast Breeder Reactor Program (LMFBR). ORNL assisted by Combustion Engineering, initiated a program to develop a 9Cr-1Mo steel for 512 C (970 F) service temperature and with toughness of 54 J (40 ft-lbs) at room temperature 36, 37. This was achieved through the controlled addi
48、tions of vanadium (V), Nb and nitrogen (N) to become Grade 91. Later, the carbon content in Grade 91 was lowered to the range of 0.08 % to 0.12 % from 0.15 % maximum specified for the standard 9Cr-1Mo steel.In the 1980s, it was recognized that the elevated temperature mechanical properties of Grade
49、91 made it a viable candidate for utility boiler applications. Code Case 1943 20 approved on July 20, 1983, permitted the use of Grade 91 for Section I construction. The 9Cr-1Mo-V alloy steels are now included in Section II, Part D for ASME Section VIII, Division 1 2, applications up to 649 C (1200 F) but their use is not permitted in ASME Section VIII, Division 2 4, except as allowed by Code Case 1973-2 22. This alloy also has allowable stresses about 50 % higher than standard 9Cr-1Mo alloy steel for temperatures up to 510 C (950 F) and the difference is significantly m
