1、Designation: A 995/A 995M 98 (Reapproved 2007)Standard Specification forCastings, Austenitic-Ferritic (Duplex) Stainless Steel, forPressure-Containing Parts1This standard is issued under the fixed designationA 995/A 995M; the number immediately following the designation indicates the yearof original
2、 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. Scope1.1 This specification covers austenitic-ferritic (duplex)stainless ste
3、el castings for valves, 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 grade
4、s will develop arange 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 pos
5、sibility of precipitation of embrittlingphases, the grades included in this specification are not recommended forservice at temperatures above 600F 315C.1.3 The values stated in either inch-pound units or SI unitsare to be regarded separately as standard. Within the text, theSI units are shown in br
6、ackets. 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.2. Referenced Documents2.1 ASTM Standards:2A 488/A 488M Practice for Steel Casti
7、ngs, Welding, Quali-fications of Procedures and PersonnelA 703/A 703M Specification for Steel Castings, GeneralRequirements, for Pressure-Containing PartsE 125 Reference Photographs for Magnetic Particle Indica-tions on Ferrous CastingsE 165 Test Method for Liquid Penetrant ExaminationE 562 Test Met
8、hod for Determining Volume Fraction bySystematic Manual Point Count3. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 duplex stainless steelan iron-chromium-nickel-molybdenum alloy which when properly heat treated consistsof approximately 30 to 60 % ferrite with the balance auste
9、nite.4. General Conditions for Delivery4.1 Material furnished to this specification shall conform tothe applicable requirements of Specification A 703/A 703M,including the supplementary requirements that are indicated onthe purchaser order. Failure to comply with the generalrequirements of Specifica
10、tion A 703/A 703M constitutes non-conformance with this specification. In case of conflict be-tween the requirements of the specification and SpecificationA 703/A 703M, this specification shall prevail.5. Ordering Information5.1 It is the responsibility of the purchaser to specify allrequirements th
11、at are necessary for material ordered under thisspecification. Such requirements may included, but are notlimited to, the following:1This specification is under the jurisdiction of ASTM Committee A01 on Steel,Stainless Steel and Related Alloys and is the direct responsibility of SubcommitteeA01.18 o
12、n Castings.Current edition approved Nov. 1, 2007. Published December 2007. Originallyapproved in 1998. Last previous edition approved in 2003 as A 995 98 (2003).2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book o
13、f ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.TABLE 1 Heat Treatment RequirementsGrade Heat Treatment1B Heat to 1900F 1040C minimum, hold for sufficient time to heatcasting uniformly to temperature, quench in water or rapid cool byother means.2A
14、Heat to 2050F 1120C minimum, hold for sufficient time to heatcasting uniformly to temperature, quench in water or rapid cool byother means.3A Heat to 1950F 1070C minimum, hold for sufficient time to heatcasting uniformly to temperature, quench in water or rapid cool byother means.4A Heat to 2050F 11
15、20C minimum for sufficient time to heat castinguniformly to temperature and water quench, or the casting may befurnace cooled to 1850F 1010C 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 2050F 1120C minimum, hold
16、for sufficient time to heatcasting to temperature, furnace cool to 1910F 1045C minimum,quench in water or rapid cool by other means.6A Heat to 2010F 1100C minimum, hold for sufficient time to heatcasting uniformly to temperature, quench in water or cool rapidly byother means.1Copyright ASTM Internat
17、ional, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5.1.1 A description of the casting by pattern number ordrawing (dimensional tolerances shall be included on thecasting drawing),5.1.2 Quantity (weight and number of castings),5.1.3 Specification designation an
18、d date of issue,5.1.4 Grade of steel,5.1.5 Supplementary requirements including acceptance cri-teria, and5.1.6 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 shall be heat treated in acc
19、ordance 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 prescribedin Table 3.10. Qua
20、lity10.1 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 A 488/A 488M.11.2 The composition of the deposited weld metal may besimilar to that of the cas
21、ting 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.11.4 When postweld heat treatment is believed necessaryfor adequate corrosion resistance or impact tou
22、ghness, Supple-mentary Requirement S11, Post Weld Heat Treatment, shall beincluded in the purchase order.12. Post Weld Heat Treatment After Major Weld Repair12.1 Weld repairs shall be considered major in the case of acasting that has leaked on hydrostatic testing or when the depthof the cavity after
23、 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 other weld repairs shall be considered minor.12.2 Castings shall be heat-treated after major weld repairs.Heat treatment af
24、ter minor weld repairs is not required exceptupon agreement between the manufacturer and the purchaser.12.3 Post weld heat treatment shall be in accordance withTable 1.13. Keywords13.1 austenitic-ferritic; duplex stainless steel; pressure-containing; steel castingsTABLE 2 Chemical RequirementsGrade
25、1B 2A 3A 4A 5AA6AAType 25Cr-5Ni-M0-Cu-N 24Cr-10Ni-Mo-N 25Cr-5Ni-Mo-N 22Cr-5Ni-Mo-N 25Cr-7Ni-Mo-N 25Cr-7Ni-Mo-NUNS J93372 J93345 J93371 J92205 J93404 J93380ACI CD4MCuN CE8MN CD6MN CD3MN CE3MN CD3MWCuNComposition:Carbon, max 0.040 0.080 0.060 0.030 0.030 0.030Manganese, max 1.00 1.00 1.00 1.50 1.50 1.
26、00Silicon, max 1.00 1.50 1.00 1.00 1.00 1.00Phosphorus, max 0.040 0.040 0.040 0.040 0.040 0.030Sulfur, max 0.040 0.040 0.040 0.020 0.040 0.025Chromium 24.5-26.5 22.5-25.5 24.0-27.0 21.0-23.5 24.0-26.0 24.0-26.0Nickel 4.7-6.0 8.0-11.0 4.0-6.0 4.5-6.5 6.0-8.0 6.5-8.5Molybdenum 1.70-2.30 3.0-4.5 1.75-2
27、.50 2.5-3.5 4.0-5.0 3.0-4.0Copper 2.7-3.3 . . . . . . 1.00, max . . . 0.50-1.00Tungsten . . . . . . . . . . . . . . . 0.50-1.00Nitrogen 0.10-0.25 0.10-0.30 0.15-0.25 0.10-0.30 0.10-0.30 0.20-0.30A%Cr+3.3%Mo+16%N$ 40.TABLE 3 Tensile RequirementsGrade 1B 2A 3A 4A 5A 6AType 25Cr-5Ni-Mo-Cu-N 24Cr-10Ni-M
28、o-N 25Cr-5Ni-Mo-N 22Cr-5Ni-Mo-N 25Cr-7Ni-Mo-N 25Cr-7Ni-Mo-NTensile strength, ksi MPa, min 100 690 95 655 95 655 90 620 100 690 100 690Yield strength (0.2 % offset), ksi MPa,min70 485 65 450 65 450 60 415 75 515 65 450Elongation in 2 in. 50 mm, %, minA16 25 25 25 18 25AWhen ICI test bars are used in
29、tensile testing as provided for in this specification, the gage length to reduced section diameter ratio shall be 4:1.A 995/A 995M 98 (2007)2SUPPLEMENTARY REQUIREMENTSThe following supplementary requirements shall not apply unless specified in the purchase order. Alist of standardized supplementary
30、requirements for use at the option of the purchaser is included inSpecification A 703/A 703M. Those which are ordinarily considered suitable for use with thisspecification are given below. Others enumerated in Specification A 703/A 703M may be used withthis specification upon agreement between the m
31、anufacturer and purchaser.S1. Unspecified ElementsS2. Destruction TestsS5. Radiographic InspectionS6. Liquid Penetrant InspectionS8. Charpy Impact TestS10. Examination of Weld PreparationS10.1 Liquid penetrant examination of cavities prepared forwelding shall be performed to verify removal of those
32、discon-tinuities found unacceptable by the inspection method specifiedfor the casting. The method of performing liquid penetrantexamination shall be in accordance the with Practice E 165.Unless other degrees of shrinkage or types of discontinuitiesfound in the cavities are specified, Type II, Intern
33、al Shrinkage,of Reference Photographs E 125, of Degree 2 in sections up to2 in. 50 mm thick and of Degree 3 in sections over 2 in. 50mm 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 Approv
34、al of Major Weld RepairsOther supplementary requirements considered suitable foruse with this specification are:S50. Estimating Ferrite ContentS50.1 Ferrite contents shall be determined by point count(Practice E 562), by other quantitative metallographic methodssuch as image analysis, by measurement
35、 of magnetic response,or by other methods upon agreement between the manufacturerand the purchaser. Frequency of testing and location of testsshall be by agreement between the manufacturer and thepurchaser.S51. Prior Approval of Weld MaterialS51.1 The purchaser must give approval of all weld fillerm
36、aterials to be used prior to any weld repairs.ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, a
37、nd the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revis
38、ion of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you s
39、houldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).A 995/A 995M 98 (2007)3
