1、Designation: A988/A988M 11Standard Specification forHot Isostatically-Pressed Stainless Steel Flanges, Fittings,Valves, and Parts for High Temperature Service1This standard is issued under the fixed designation A988/A988M; the number immediately following the designation indicates the yearof origina
2、l adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval.A superscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This specification covers hot isostatically-pressed, pow-der meta
3、llurgy, stainless steel piping components for use inpressure systems. Included are flanges, fittings, valves, andsimilar parts made to specified dimensions or to dimensionalstandards, such as in ASME specification B16.5.1.2 Several grades of martensitic, austenitic, age hardening,and austenitic-ferr
4、itic stainless steels are included in thisspecification.1.3 Supplementary requirements are provided for use whenadditional testing or inspection is desired. These shall applyonly when specified individually by the purchaser in the order.1.4 This specification is expressed in both inch-pound unitsand
5、 in SI units. Unless the order specifies the applicable “M”specification designation (SI units), however, the material shallbe furnished to inch-pound units.1.5 The values stated in either inch-pound units or SI unitsare to be regarded separately as the standard. Within the text,the SI units are sho
6、wn in parentheses. The values stated in eachsystem may not be exact equivalents; therefore, each systemshall be used independently of the other. Combining valuesfrom the two systems may result in non-conformance with thestandard.1.6 The following safety hazards caveat pertains only to testmethods po
7、rtions 8.1, 8.2, 9.5-9.7, and Section 10 of thisspecification: This standard does not purport to address all ofthe safety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bi
8、lity of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2A262 Practices for Detecting Susceptibility to IntergranularAttack in Austenitic Stainless SteelsA275/A275M Practice for Magnetic Particle Examinationof Steel ForgingsA745/A745M Practice for Ultrasonic Examination
9、 of Aus-tenitic Steel ForgingsA751 Test Methods, Practices, and Terminology for Chemi-cal Analysis of Steel ProductsA923 Test Methods for Detecting Detrimental IntermetallicPhase in Duplex Austenitic/Ferritic Stainless SteelsA961/A961M Specification for Common Requirements forSteel Flanges, Forged F
10、ittings, Valves, and Parts for PipingApplicationsB311 Test Method for Density of Powder Metallurgy (PM)Materials Containing Less Than Two Percent PorosityE112 Test Methods for Determining Average Grain SizeE165 Practice for Liquid Penetrant Examination for GeneralIndustryE340 Test Method for Macroet
11、ching Metals and AlloysE606 Practice for Strain-Controlled Fatigue TestingG48 Test Methods for Pitting and Crevice Corrosion Resis-tance of Stainless Steels and Related Alloys by Use ofFerric Chloride Solution2.2 MSS Standard:SP 25 Standard Marking System for Valves, Fittings,Flanges, and Unions32.3
12、 ASME Specifications and Boiler and Pressure VesselCodes:B16.5 Dimensional Standards for Steel Pipe Flanges andFlanged Fittings42.4 ASME Specification IX Welding Qualifications:SFA-5.4 Specification for Corrosion-Resisting Chromiumand Chromium-Nickel Steel Covered Welding Electrodes4SFA-5.9 Specific
13、ation for Corrosion-Resisting Chromiumand Chromium-Nickel Steel Welding Rods and BareElectrodes41This specification is under the jurisdiction of ASTM Committee A01 on Steel,Stainless Steel and Related Alloys and is the direct responsibility of SubcommitteeA01.22 onSteel Forgings and Wrought Fittings
14、 for Piping Applications and BoltingMaterials for Piping and Special Purpose Applications.Current edition approved May 1, 2011. Published June 2011. Originallyapproved in 1998. Last previous edition approved in 2007 as A988/A988M 07.DOI: 10.1520/A0988_A0988M-11.2For referenced ASTM standards, visit
15、the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from Manufacturers Standardization Society of the Valve and FittingsIndustry (MSS), 127
16、Park St., NE, Vienna, VA 22180-4602, http:/www.mss-.4Available from American Society of Mechanical Engineers (ASME), ASMEInternational Headquarters, Three Park Ave., New York, NY 10016-5990, http:/www.asme.org.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM Internat
17、ional, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.SFA-5.11 Specification for Nickel and Nickel-Alloy Cov-ered Welding Electrodes43. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 can, nthe container used to encapsulate the powderduring th
18、e pressure consolidation process; it is partially or fullyremoved from the final part.3.1.2 compact, nthe consolidated powder from one can. Itmay be used to make one or more parts.3.1.3 consolidation, nthe bonding of adjacent powderparticles in a compact under pressure by heating to a tempera-ture b
19、elow the melting point of the powder.3.1.4 fill stem, nthe part of the compact used to fill thecan. It is not usually integral to the part produced.3.1.5 hot isostatic-pressing, na process for simultane-ously heating and forming a compact in which the powder iscontained in a sealed formable enclosur
20、e usually made frommetal and the so-contained powder is subjected to equalpressure from all directions at a temperature high enough topermit plastic deformation and consolidation of the powderparticles to take place.3.1.6 lot, na number of parts made from a single powderblend following the same manu
21、facturing practice.3.1.7 part, na single item coming from a compact, eitherprior to or after machining.3.1.8 powder blend, na homogeneous mixture of powderfrom one or more heats of the same grade.3.1.9 rough part, nthe part prior to final machining.4. Ordering Information4.1 It is the responsibility
22、 of the purchaser to specify in thepurchase order all requirements that are necessary for materialordered under this specification. Such requirements may in-clude, but are not limited to, the following:4.1.1 Quantity (weight or number of parts),4.1.2 Name of material or UNS number,4.1.3 ASTM designa
23、tion and year of issue,4.1.4 Dimensions (tolerances and surface finishes should beincluded),4.1.5 Microstructure examination if required (5.1.4),4.1.6 Inspection (15.1),4.1.7 Whether rough part or finished machined part (8.2.2),4.1.8 Supplementary requirements, if any,4.1.9 Additional requirements (
24、See 7.2 and 17.1), and4.1.10 Requirement, if any, that the manufacturer shallsubmit drawings for approval showing the shape of the roughpart before machining and the exact location of test specimenmaterial (See 9.3).TABLE 1 Chemical RequirementsComposition, %AUNSDesignationGrade Carbon Manganese Pho
25、sphorus Sulfur Silicon Nickel Chromium MolybdenumColumbiumplus TantalumTantalum TitaniumMartensitic Stainless SteelsS41000 13 chromium 0.15 1.00 0.040 0.030 1.00 11.513.5 . . . . . . . . . . . .S41026 13 chromium 0.15 1.00 0.020 0.020 1.00 1.002.00 11.513.5 0.400.60 Other Elements0.5 molybdenum Cu 0
26、.50S41500 13 chromium, 4 0.05 0.501.00 0.030 0.030 0.60 3.55.5 11.514.0 0.501.00 . . . . . . . . .nickelS42390 12 chromium, 1.0 0.180.25 1.00 0.030 0.030 1.00 0.300.80 11.512.5 0.801.20 Other Elementsmolybdenum, N 0.030.08modified V 0.250.35with vanadium Cb 0.080.15Austenitic Stainless SteelsS30400B
27、18 chromium, 8nickel0.08 2.00 0.045 0.030 1.00 8.011.0 18.020.0 . . . . . . . . . . . .S30403B18 chromium, 8nickel,low carbon0.035 2.00 0.045 0.030 1.00 8.013.0 18.020.0 . . . . . . . . . . . .S30451C18 chromium, 8nickel,modified withnitrogen0.08 2.00 0.045 0.030 1.00 8.011.0 18.020.0 . . . . . . .
28、. . . . .S30453 18 chromium, 8nickel,modified withnitrogen0.030 2.00 0.045 0.030 1.00 8.011.0 18.020.0 . . . . . . . . . . . .S31600B18 chromium, 8nickel,modified withmolybdenum0.08 2.00 0.045 0.030 1.00 10.014.0 16.018.0 2.003.00 . . . . . . . . .S31603B18 chromium, 8nickel,modified withmolybdenum,
29、 lowcarbon0.030 2.00 0.045 0.030 1.00 10.014.0 16.018.0 2.003.00 . . . . . . . . .A988/A988M 112TABLE 1 ContinuedComposition, %AUNSDesignationGrade Carbon Manganese Phosphorus Sulfur Silicon Nickel Chromium MolybdenumColumbiumplus TantalumTantalum TitaniumS31651C18 chromium, 8nickel,modified withmol
30、ybdenum andnitrogen0.08 2.00 0.045 0.030 1.00 10.013.0 16.018.0 2.003.00 . . . . . . . . .S31653C18 chromium, 8nickel,modified withmolybdenum andnitrogen0.030 2.00 0.045 0.030 1.00 10.013.0 16.018.0 2.003.00 . . . . . . . . .S31700 19 chromium, 13nickel3.5 molybdenum0.08 2.00 0.045 0.030 1.00 11.015
31、.0 18.0-20.0 3.04.0 . . . . . . . . .S31703 19 chromium, 13nickel,3.5 molybdenum0.030 2.00 0.045 0.030 1.00 11.015.0 18.020.0 3.04.0 . . . . . . . . .S21904 20 chromium, 6nickel, 9manganese0.04 8.010.0 0.045 0.030 1.00 5.57.5 19.021.5 . . . . . . Other ElementsN 0.150.40S31254 20 chromium, 18nickel,
32、 6molybdenum, lowcarbon0.020 1.00 0.030 0.010 0.80 17.518.5 19.520.5 6.06.5 . . . Other ElementsCu 0.50-1.00N 0.18-0.22S31725 19 chromium, 15nickel, 4molybdenum0.030 2.00 0.045 0.030 1.00 13.517.5 18.020.0 4.05.0 . . . Other elementsN 0.20S31726 19 chromium, 15nickel, 4molybdenum0.030 2.00 0.045 0.0
33、30 1.00 14.517.5 17.020.0 4.05.0 . . . Other ElementsN 0.100.20N08367 22 chromium, 25nickel,6.5 molybdenum,lowcarbon0.030 2.00 0.040 0.030 1.00 23.5025.5020.022.0 6.07.0 Other ElementsN 0.180.25Cu 0.75S32654 25 chromium, 22nickel,7 molybdenum, lowcarbon0.020 2.04.0 0.030 0.005 0.50 21.023.0 24.025.0
34、 7.08.0 Other ElementsN 0.450.55Cu 0.300.60Age-Hardening Stainless SteelsS17400 17 chromium, 4nickel, 3 copper0.07 1.00 0.040 0.030 1.00 3.05.0 15.017.5 . . . 0.150.45 Other ElementsCu 3.05.0Austenitic-Ferritic Stainless SteelsS31803 22 chromium, 5.5nickel,modified withnitrogen0.030 2.00 0.030 0.020
35、 1.00 4.56.5 21.023.0 2.53.5 . . . Other ElementsN 0.080.20S32205 22 chromium, 5.5nickel, modifiedwith high nitrogen0.030 2.00 0.030 0.020 1.00 4.56.5 22.023.0 3.03.5 Other ElementsCu 0.75N 0.14-0.20S32950 26 chromium, 3.5nickel,1.0 molybdenum0.030 2.00 0.035 0.010 0.60 3.55.2 26.029.0 1.002.50 . .
36、. Other ElementsN 0.15-0.35S32750 25 chromium, 7nickel, 4molybdenum,modified withnitrogen0.030 1.20 0.035 0.020 0.80 6.0-8.0 24.026.0 3.0-5.0 . . . Other ElementsN 0.240.32Cu 0.50S39274 25 chromium, 7nickel,modified withnitrogenand tungsten0.030 1.0 0.030 0.020 0.80 6.08.0 24.026.0 2.53.5 . . . Othe
37、r ElementsN 0.240.32Cu 0.200.80W 1.502.50S32760D25 chromium, 7nickel, 3.5molybdenum,modified withnitrogen andtungsten0.030 1.00 0.030 0.010 1.00 6.08.0 24.026.0 3.04.0 . . . Other ElementsN 0.200.30Cu 0.501.00W 0.501.00A988/A988M 113TABLE 1 ContinuedComposition, %AUNSDesignationGrade Carbon Manganes
38、e Phosphorus Sulfur Silicon Nickel Chromium MolybdenumColumbiumplus TantalumTantalum TitaniumS39277 25 chromium, 7nickel,3.7 molybdenum0.025 0.80 0.025 0.002 0.80 6.58.0 24.026.0 3.04.0 . . . Other ElementsCu 1.202.00W 0.801.20N 0.230.33S32505 27 chromium, 7nickel, 3molybdenum,modified withnitrogen
39、and copper0.030 1.50 0.030 0.020 1.00 4.57.0 24.027.0 2.93.9 . . . Other ElementsCu 1.502.50N 0.250.30AMaximum, unless otherwise specified.BS30400, S30403, S31600, and S31603 shall have a maximum nitrogen content of 0.10 %.CS30451, S31651, S30453, S31653 shall have a nitrogen content of 0.10 to 0.16
40、 %.D%Cr+3.33 %Mo+163 %N40min.5. Materials and Manufacture5.1 Manufacturing Practice:5.1.1 Compacts shall be manufactured by placing a singlepowder blend into a can, evacuating the can, and sealing it. Thecan material shall be selected to ensure that it has no deleteri-ous effect on the final product
41、. The entire assembly shall beheated and placed under sufficient pressure for a sufficientperiod of time to ensure that the final consolidated part meetsthe density requirements of 8.1.1.1. One or more parts shall bemachined from a single compact.5.1.2 The powder shall be prealloyed and made by a me
42、ltingmethod capable of producing the specified chemical composi-tion, such as but not limited to, air or vacuum inductionmelting, followed by gas atomization.5.1.3 When powder from more than one heat of the samegrade is used to make a blend, the heats shall be mixedthoroughly to ensure homogeneity.5
43、.1.4 The compact shall be sectioned and the microstructureexamined to check for porosity and other internal imperfec-tions. It shall meet the requirements of 8.1.2. The sample shallbe taken from the fill stem or from a location in a part as agreedupon by the manufacturer and purchaser.5.1.5 Unless o
44、therwise specified in the purchase order, themanufacturer shall remove the can material from the surfacesof the consolidated compacts by chemical or mechanicalmethods such as by pickling or machining. This removal shallbe done before or after heat treatment at the option of themanufacturer (See Note
45、 1).NOTE 1Often, it is advantageous to leave the can material in placeuntil after heat treatment or further thermal processing of the consolidatedcompact.6. Chemical Composition6.1 The steel, both as a blend and as a part, shall conform tothe requirements for chemical composition prescribed in Table
46、1. Test Methods, Practices, and Terminology of A751 shallapply.6.1.1 A representative sample of each blend of powder shallbe analyzed by the manufacturer to determine the percentage ofelements prescribed in Table 1. The blend shall conform to thechemical composition requirements prescribed in Table
47、1.6.1.2 When required by the purchaser, the chemical com-position of a sample from one part from each lot of parts shallbe determined by the manufacturer. The composition of thesample shall conform to the chemical requirements prescribedin Table 1.6.2 Addition of lead, selenium, or other unspecified
48、 ele-ments for the purpose of improving the machinability of thecompact shall not be permitted.6.3 The steel shall not contain an unspecified element otherthan nitrogen, for the ordered grade, to the extent that the steelconforms to the requirements of another grade for which thatelement is a specif
49、ied element having a required minimumcontent.7. Heat Treatment7.1 Except as provided in 7.2, the final heat treatment of allparts shall be in compliance with the requirements of Table 2.After hot isostatic-pressing and prior to final heat treatment, thecompacts are permitted to be annealed, at the option of theproducer, either as a part of the consolidation process or as aseparate operation.7.2 When agreed upon by the purchaser, liquid quenchingmay be applied to
