1、Designation: A 988/A 988M 07Standard Specification forHot Isostatically-Pressed Stainless Steel Flanges, Fittings,Valves, and Parts for High Temperature Service1This standard is issued under the fixed designationA 988/A 988M; the number immediately following the designation indicates the yearof orig
2、inal 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 (e) indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This specification covers hot isostatically-pressed, pow-der
3、metallurgy, 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-
4、ferritic 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 unit
5、sand 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
6、 shown in parentheses. The values stated in eachsystem are not exact equivalents; therefore, each system mustbe used independently of the other. Combining values from thetwo systems may result in nonconformance with the specifi-cation.1.6 The following safety hazards caveat pertains only to testmeth
7、ods portions 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 appl
8、ica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2A 262 Practices for Detecting Susceptibility to Intergranu-lar Attack in Austenitic Stainless SteelsA 275/A 275M Practice for Magnetic Particle Examinationof Steel ForgingsA 370 Test Methods and Definitions
9、for Mechanical Testingof Steel ProductsA 745/A 745M Practice for Ultrasonic Examination ofAus-tenitic Steel ForgingsA 751 Test Methods, Practices, and Terminology forChemical Analysis of Steel ProductsA 923 Test Methods for Detecting Detrimental IntermetallicPhase in Duplex Austenitic/Ferritic Stain
10、less SteelsB311 Test Method for Density Determination for PowderMetallurgy (P/M) Materials Containing Less Than TwoPercent PorosityE112 Test Methods for Determining Average Grain SizeE 165 Test Method for Liquid Penetrant ExaminationE 340 Test Method for Macroetching Metals and AlloysE 606 Practice
11、for Strain-Controlled Fatigue TestingG48 Test Methods for Pitting and Crevice Corrosion Re-sistance 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 ASME Specifications and Boiler and P
12、ressure 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 Specification for Corrosion-Resisting Chromiu
13、mand Chromium-Nickel Steel Welding Rods and BareElectrodes4SFA-5.11 Specification for Nickel and Nickel-Alloy Cov-ered Welding Electrodes41This specification is under the jurisdiction of ASTM Committee A01 on Steel,Stainless Steel and Related Alloys and is the direct responsibility of SubcommitteeA0
14、1.22 onSteel Forgings and Wrought Fittings for Piping Applications and BoltingMaterials for Piping and Special Purpose Applications.Current edition approved Sept. 1, 2007. Published October 2007. Originallyapproved in 1998. Last previous edition approved in 2005 as A 988/A 988M 05.2For referenced AS
15、TM standards, visit 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 Fittings
16、Industry (MSS), 127 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.Cop
17、yright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 can, nthe container used to encapsulate the powderduring the pressure consolidation process; it is partially or fullyr
18、emoved 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 below the melting point of the powder.3.1.4 fill stem, nthe
19、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 simulta-neously heating and forming a compact in which the powder iscontained in a sealed formable enclosure usually made frommetal and the so-contained powder is sub
20、jected 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 manufacturing practice.3.1.7 part, na single item coming from a
21、 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 of the purchaser to specify in thepurchase order all requi
22、rements 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 designation and year of issue,4.1.4 Dimensions (tolerances and sur
23、face 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 (See 7.2 and 17.1), and4.1.10 Requirement, if any, that the
24、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 Phosphorus Sulfur Silicon Nickel Chromium MolybdenumColumbiump
25、lus 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 0.50S41500 13 chromium, 4 0.05 0.501.00 0.030 0.030 0.60 3.5
26、5.5 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 SteelsS30400B18 chromium, 8nickel0.08 2.00 0.045 0.030 1.00 8.011.0 18.0
27、20.0 . . . . . . . . . . . .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 . . . . . . . . . . . .S30453 18 chromium, 8nickel,modified withnitrogen0
28、.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, lowcarbon0.030 2.00 0.045 0.030 1.00 10.014.0 16.018.0 2.0
29、03.00 . . . . . . . . .A 988/A 988M 072TABLE 1 ContinuedComposition, %AUNSDesignationGrade Carbon Manganese Phosphorus Sulfur Silicon Nickel Chromium MolybdenumColumbiumplus TantalumTantalum TitaniumS31651C18 chromium, 8nickel,modified withmolybdenum andnitrogen0.08 2.00 0.045 0.030 1.00 10.013.0 16
30、.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 11.015.0 18.0-20.0 3.04.0 . . . . . . . . .S31703 19 chromium,
31、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, 6molybdenum, lowcarbon0.020 1.00 0.030 0.010 0.80 17.518
32、.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 0.030 1.00 14.517.5 17.020.0 4.05.0 . . . Other ElementsN 0.
33、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 7.08.0 Other ElementsN 0.450.55Cu 0.300.60Age-Hardening
34、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 1.00 4.56.5 21.023.0 2.53.5 . . . Other ElementsN 0.080.
35、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 . . . Other ElementsN 0.15-0.35S32750 25 chromium, 7nickel, 4
36、molybdenum,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 . . . Other ElementsN 0.240.32Cu 0.200.80W 1.502.50S32760D25 chromi
37、um, 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 0.501.00A 988/A 988M 073TABLE 1 ContinuedComposition, %AUNSDesignationGrade Carbon Manganese Phosphorus Sulfur Silicon Nickel Chromium MolybdenumC
38、olumbiumplus 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 and copper0.030 1.50 0.030 0.020 1.00 4.57.0 24.027.0 2
39、.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 %.D%Cr+3.33 %Mo+163 %N40min.5. Materials and Manufactu
40、re5.1 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. The entire assembly shall beheated and placed under s
41、ufficient 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 meltingmethod capable of producing the specified chemical
42、 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.5.1.4 The compact shall be sectioned and the microstruct
43、ureexamined 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 otherwise specified in the purchase order, themanufactur
44、er 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 1).NOTE 1Often, it is advantageous to leave the can ma
45、terial 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 Table1. Test Methods, Practices, and Terminology of A 751 sh
46、allapply.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 1.6.1.2 When required by the purchaser, the chemical c
47、om-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 ele-ments for the purpose of improving the machinabil
48、ity 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 specified element having a required minimumcontent.7. Heat T
49、reatment7.1 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 the martensitic stainless steels in place of thefurnac
