1、Designation: A995/A995M 18aStandard Specification forCastings, Austenitic-Ferritic (Duplex) Stainless Steel, forPressure-Containing Parts1This standard is issued under the fixed designation A995/A995M; the number immediately following the designation indicates the yearof original adoption or, in the
2、 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 austenitic-ferritic (duplex)stainless steel castings for val
3、ves, flanges, fittings, and otherpressure-containing parts.1.2 The duplex stainless steels offer a combination ofenhanced mechanical properties and corrosion resistance whenproperly balanced in composition and properly heat treated.Ferrite levels are not specified, but these grades will develop aran
4、ge of approximately 30 to 60 % ferrite with the balanceaustenite. It is the responsibility of the purchaser to determinewhich grade shall be furnished depending on design andservice conditions, mechanical properties, and corrosion-resistant characteristics.NOTE 1Because of the possibility of precipi
5、tation of embrittlingphases, the grades included in this specification are not recommended forservice at temperatures above 600 F 315 C.1.3 The values stated in either SI units or inch-pound unitsare to be regarded separately as standard. The values stated ineach system may not be exact equivalents;
6、 therefore, eachsystem shall be used independently of the other. Combiningvalues from the two systems may result in nonconformancewith the standard.1.4 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision
7、on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2A488/A488M Practice for Steel Castings, Welding, Qualifi-cations of Procedures and Per
8、sonnelA703/A703M Specification for Steel Castings, GeneralRequirements, for Pressure-Containing PartsE125 Reference Photographs for Magnetic Particle Indica-tions on Ferrous CastingsE165/E165M Practice for Liquid Penetrant Examination forGeneral IndustryE562 Test Method for Determining Volume Fracti
9、on bySystematic Manual Point CountG48 Test Methods for Pitting and Crevice Corrosion Resis-tance of Stainless Steels and Related Alloys by Use ofFerric Chloride Solution3. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 duplex stainless steelan iron-chromium-nickel-molybdenum all
10、oy that, when properly heat treated, consists ofapproximately 30 to 60 % ferrite with the balance austenite.4. General Conditions for Delivery4.1 Material furnished to this specification shall conform tothe applicable requirements of Specification A703/A703M,including the supplementary requirements
11、that are indicated onthe purchaser order. Failure to comply with the generalrequirements of Specification A703/A703M constitutes non-conformance with this specification. In case of conflict be-tween the requirements of this specification and SpecificationA703/A703M, this specification shall prevail.
12、5. Ordering Information5.1 It is the responsibility of the purchaser to specify allrequirements that are necessary for material ordered under thisspecification. Such requirements may include, but are notlimited to, the following:5.1.1 A description of the casting by pattern number ordrawing (dimensi
13、onal tolerances shall be included on thecasting drawing),5.1.2 Quantity (weight and number of castings),5.1.3 Specification designation and date of issue,5.1.4 Grade of steel,5.1.5 Supplementary requirements including acceptancecriteria, and1This specification is under the jurisdiction of ASTM Commi
14、ttee A01 on Steel,Stainless Steel and Related Alloys and is the direct responsibility of SubcommitteeA01.18 on Castings.Current edition approved Sept. 1, 2018. Published October 2018. Originallyapproved in 1998. Last previous edition approved in 2018 as A995/A995M 18.DOI: 10.1520/A0995_A0995M-18A.2F
15、or referenced ASTM 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.*A Summary of Changes section appears at the end of this standa
16、rdCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of Int
17、ernational Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.15.1.6 Additional requirements.6. Process6.1 The steel shall be made by the electric furnace processwith or without separate refining.7. Heat Treatment7.1 All castings
18、shall be heat treated in accordance withTable 1.8. Chemical Composition8.1 The steel shall conform to the requirements as tochemical composition prescribed in Table 2.9. Tensile Properties9.1 One tension test shall be made from each heat and shallconform to the requirements as to tensile properties
19、prescribedin Table 3.10. Quality10.1 When additional inspection is desired, SupplementaryRequirements S5, S6, and S10 may be ordered.11. Repair by Welding11.1 Repairs shall be made using procedures and weldersqualified under Practice A488/A488M.11.2 The composition of the deposited weld metal may be
20、similar to that of the casting or may be suitably alloyed toachieve the desired corrosion resistance and mechanical prop-erties.11.3 Weld repairs shall be subject to the same qualitystandards as used to inspect the castings.12. Post-Weld Heat Treatment After Major Weld Repair12.1 Weld repairs shall
21、be considered major in the case of acasting that has leaked on hydrostatic testing or when the depthof the cavity after preparation for repair exceeds 20 % of theactual wall thickness, or 1 in. 25 mm, whichever is smaller,or when the extent of the cavity exceeds approximately 10 in.265 cm2. All othe
22、r weld repairs shall be considered minor.12.2 Castings shall be heat treated after major weld repairs.Heat treatment after minor weld repairs is not required unlessSupplementary Requirement S11 is included in the purchaseorder.12.3 Post-weld heat treatment shall be in accordance withTable 1.13. Keyw
23、ords13.1 austenitic-ferritic; duplex stainless steel; pressure-containing; steel castingsTABLE 1 Heat Treatment RequirementsGrade Heat Treatment1B Heat to 1900 F 1040 C minimum, hold for sufficient time to heatcasting uniformly to temperature, quench in water or rapid cool byother means.2A Heat to 2
24、050 F 1120 C minimum, hold for sufficient time to heatcasting uniformly to temperature, quench in water or rapid cool byother means.3A Heat to 1950 F 1070 C minimum, hold for sufficient time to heatcasting uniformly to temperature, quench in water or rapid cool byother means.4A Heat to 2050 F 1120 C
25、 minimum for sufficient time to heat castinguniformly to temperature and water quench, or the casting may befurnace cooled to 1850 F 1010 C minimum, hold for 15 minminimum and then water quench. A rapid cool by other means maybe employed in lieu of water quench.5A Heat to 2050 F 1120 C minimum, hold
26、 for sufficient time to heatcasting to temperature, furnace cool to 1910 F 1045 C minimum,quench in water or rapid cool by other means.6A Heat to 2010 F 1100 C minimum, hold for sufficient time to heatcasting uniformly to temperature, quench in water or rapid cool byother means, or the casting may b
27、e furnace cooled to a temperatureno lower than 1925 F 1050 C, hold for 15 min minimum, and thenquench in water or rapid cool by other means.7A Heat to 2065 F 1130 C minimum, hold for sufficient time to heatcasting to temperature, furnace cool to 1940 F 1060 C minimum,quench in water or rapid cool by
28、 other means.A995/A995M 18a2SUPPLEMENTARY REQUIREMENTSThe following supplementary requirements shall not apply unless specified in the purchase order.Alist of standardized supplementary requirements for use at the option of the purchaser is included inSpecification A703/A703M. Those which are ordina
29、rily considered suitable for use with thisspecification are given below. Others enumerated in Specification A703/A703M may be used with thisspecification upon agreement between the manufacturer and purchaser.S1. Unspecified ElementsS2. Destruction TestsS5. Radiographic InspectionS6. Liquid Penetrant
30、 InspectionS8. Charpy Impact TestS10. Examination of Weld PreparationS10.1 Liquid penetrant examination of cavities prepared forwelding shall be performed to verify removal of those discon-tinuities found unacceptable by the inspection method specifiedfor the casting. The method of performing liquid
31、 penetrantexamination shall be in accordance with Practice E165/E165M. Unless other degrees of shrinkage or types of discon-tinuities found in the cavities are specified, Type II, InternalShrinkage, of Reference Photographs E125, of Degree 2 insections up to 2 in. 50 mm thick, and of Degree 3 in sec
32、tionsover 2 in. 50 mm thick shall be acceptable.S11. Post-Weld Heat TreatmentS11.1 Castings shall be given a post-weld solution heattreatment in accordance with Table 1.S12. Prior Approval of Major Weld RepairsOther supplementary requirements considered suitable foruse with this specification are:TA
33、BLE 2 Chemical RequirementsGrade 1B 2A 3A 4A 5AA6AA7ABType 25Cr-5Ni-Mo-Cu-N24Cr-10Ni-Mo-N 25Cr-5Ni-Mo-N 22Cr-5Ni-Mo-N 25Cr-7Ni-Mo-N 25Cr-7Ni-Mo-N 27Cr-7Ni-Mo-W-NUNS J93372 J93345 J93371 J92205 J93404 J93380 J93379ACI CD4MCuN CE8MN CD6MN CD3MN CE3MN CD3MWCuN CD3MWNComposition:Carbon, max 0.040 0.080
34、0.060 0.030 0.030 0.030 0.030Manganese, max 1.00 1.00 1.00 1.50 1.50 1.00 1.003.00Silicon, max 1.00 1.50 1.00 1.00 1.00 1.00 1.00Phosphorus, max 0.040 0.040 0.040 0.040 0.040 0.030 0.030Sulfur, max 0.040 0.040 0.040 0.020 0.040 0.025 0.020Chromium 24.526.5 22.525.5 24.027.0 21.023.5 24.026.0 24.026.
35、0 26.028.0Nickel 4.76.0 8.011.0 4.06.0 4.56.5 6.08.0 6.58.5 6.08.0Molybdenum 1.702.30 3.04.5 1.752.50 2.53.5 4.05.0 3.04.0 2.03.5Copper 2.73.3 . . . . . . 1.00, max . . . 0.501.00 1.00 maxTungsten . . . . . . . . . . . . . . . 0.501.00 3.04.0Nitrogen 0.100.25 0.100.30 0.150.25 0.100.30 0.100.30 0.20
36、0.30 0.300.40Boron . . . . . . . . . . . . . . . . . . 0.00100.0100Barium . . . . . . . . . . . . . . . . . . 0.00020.0100Ce + La . . . . . . . . . . . . . . . . . . 0.0050.030A%Cr+3.3%Mo+16%N$ 40.B%Cr+3.3(%Mo+0.5%W)+16%N$ 45.TABLE 3 Tensile RequirementsGrade 1B 2A 3A 4A 5A 6A 7AType 25Cr-5Ni-Mo-Cu-
37、N24Cr-10Ni-Mo-N25Cr-5Ni-Mo-N22Cr-5Ni-Mo-N25Cr-7Ni-Mo-N25Cr-7Ni-Mo-N27Cr-7Ni-Mo-W-NTensile strength,ksi MPa, min100 690 95 655 95 655 90 620 100 690 100 690 100 690Yield strength(0.2 % offset),ksi MPa, min70 485 65 450 65 450 60 415 75 515 65 450 75 515Elongation in 2 in.50 mm,%, minA16 25 25 25 18 2
38、5 20AWhen ICI test bars are used in tensile testing as provided for in this specification, the gage length to reduced section diameter ratio shall be 4:1.A995/A995M 18a3S50. Estimating Ferrite ContentS50.1 Ferrite contents shall be determined by point count(Test Method E562), by other quantitative m
39、etallographicmethods such as image analysis, by measurement of magneticresponse, or by other methods upon agreement between themanufacturer and the purchaser. Frequency of testing andlocation of tests shall be by agreement between the manufac-turer and the purchaser.S51. Prior Approval of Weld Mater
40、ialS51.1 The purchaser must give approval of all weld fillermaterials to be used prior to any weld repairs.S52. Additional Requirements for Grade 6AS52.1 Casting Thickness, TThe casting thickness, T,isthemaximum thickness of the pressure-containing wall of thecasting exclusive of padding added for d
41、irectionalsolidification, flanges, appendages, and sections designated bythe designer as noncritical. The order, inquiry, and drawingshall designate what the test dimension, T, is for the casting.S52.2 Charpy Impact TestCharpy impact test propertiesshall be determined by testing a set of three Charp
42、y V-notchimpact specimens made from each heat of material.S52.2.1 The thickness of the test blocks used to createCharpy impact test specimens shall be equal to the castingthickness, T. Charpy impact test specimens shall be removedfrom a location at one-half the thickness of the test block.S52.2.2 Wh
43、en the thickness of the test block is less than orequal to 4 in. 100 mm, Charpy impact testing shall beperformed at one of the test temperatures listed in Table S52.1.The test temperature shall be provided by the purchaser. If thetest temperature is not specified, the test temperature used shallbe 5
44、1 F 46 C. The average value of the three specimensshall not be less than specified in Table S52.1, with no morethan one value permitted below the average minimum specifiedand no value permitted below the minimum specified for asingle specimen.S52.2.3 When the thickness of the test block is greater t
45、han4 in. 100 mm, test temperature and absorbed energy valuesshall be agreed upon between the purchaser and the manufac-turer.S52.3 Corrosion TestingA Test Methods G48 Method Aferric chloride pitting resistance test shall be performed for aduration of 24 h at 60 C.S52.3.1 The thickness of the test bl
46、ocks used to createcorrosion test specimens shall be equal to the casting thickness,T. Corrosion test specimens shall be removed from a locationat one-quarter the thickness of the test block.S52.3.2 When the thickness of the test block is less than orequal to 4 in. 100 mm, test specimens shall show
47、no evidenceof pitting when examined optically at 20 magnification, andhave a weight loss of 4g/m2.S52.3.3 When the thickness of the test block is greater than4 in. 100 mm, test block size and acceptance criteria shall beagreed upon between the purchaser and the manufacturer.S52.4 Weld Qualifications
48、Repairs shall be made utilizingwelding procedures qualified in accordance with Section IX oftheASME Boiler and PressureVessel Code, and repair weldingshall be done by welders or welding operators meeting thequalification requirements of Section IX. In addition to theSection IX qualification limits,
49、the weld test plate thicknessshall be as agreed upon between the casting supplier and thepurchaser, but no less than 1.5 times the maximum weld repairdepth. The weld deposit thickness shall be at least 80 % of themaximum repair depth.S52.4.1 When the thickness of the qualification coupon isless than or equal to 4 in. 100 mm, and the qualificationcoupon is subjected to a post-weld solution heat treatment inaccordance with Table 1, Cha
