1、Designation: A 957/A 957M 08Standard Specification forInvestment Castings, Steel and Alloy, CommonRequirements, for General Industrial Use1This standard is issued under the fixed designationA 957/A 957M; the number immediately following the designation indicates the yearof original adoption or, in t
2、he 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 a group of requirements thatare mandatory for castings pr
3、oduced by the investment castingprocess to meet the metallurgical requirements of the followingsteel casting specifications issued by ASTM.ASTM Designation Title of SpecificationA 27/A 27M Steel Castings, Carbon, for General Ap-plicationA 148/A 148M Steel Castings, High-Strength, for Struc-tural Pur
4、posesA 297/A 297M Steel Castings, Iron-Chromium and Iron-Chromium-Nickel, Heat-Resistant, forGeneral ApplicationA 447/A 447M Steel Castings, Chromium-Nickel-Iron Al-loy (25-12 Class), for High-TemperatureServiceA 494/A 494M Castings, Nickel and Nickel AlloyA 560/A 560M Castings, Chromium-Nickel Allo
5、yA 732/A 732M Castings, Investment, Carbon and LowAlloy Steel for General Application, andCobalt Alloy for High Strength at ElevatedTemperaturesA 743/A 743M Castings, Iron-Chromium, Iron-Chromium-Nickel, Corrosion-Resistant, for GeneralApplicationA 744/A 744M Castings, Iron-Chromium-Nickel, Corro-si
6、on Resistant, for Severe ServiceA 747/A 747M Steel Castings, Stainless, PrecipitationHardeningA 890/A 890M Castings, Iron-Chromium-Nickel-Molybdenum Corrosion-Resistant, Duplex(Austenitic/Ferritic) for General Applica-tionA 915/A 915M Steel Castings, Carbon and Alloy, Chemi-cal Requirements Similar
7、to StandardWrought Grades1.2 This specification also covers a group of supplementaryrequirements that may be applied to the above specifications asindicated therein. These are provided for use when additionaltesting or inspection is desired and apply only when specifiedindividually by the purchaser
8、in the order.1.3 When investment castings are ordered, the requirementsstated in this specification form an integral part of the materialspecification. In cases of conflict, the requirements of thisspecification shall take precedence over the individual materialspecification requirements.1.4 The val
9、ues stated in either inch-pound or SI units are tobe regarded separately as standard. Within the text, the SI unitsare shown in brackets. The values stated in each system are notexact equivalents; therefore, each system must be used inde-pendently of the other. Combining values from the two systemsm
10、ay result in nonconformance with the specification. Inch-pound units are applicable for material ordered to SpecificationA 957 and SI units for material ordered to SpecificationA 957M.2. Referenced Documents2.1 ASTM Standards:2A 27/A 27M Specification for Steel Castings, Carbon, forGeneral Applicati
11、onA 148/A 148M Specification for Steel Castings, HighStrength, for Structural PurposesA 297/A 297M Specification for Steel Castings, Iron-Chromium and Iron-Chromium-Nickel, Heat Resistant, forGeneral ApplicationA 370 Test Methods and Definitions for Mechanical Testingof Steel ProductsA 447/A 447M Sp
12、ecification for Steel Castings,Chromium-Nickel-Iron Alloy (25-12 Class), for High-Temperature ServiceA 488/A 488M Practice for Steel Castings, Welding, Quali-fications of Procedures and PersonnelA 494/A 494M Specification for Castings, Nickel andNickel AlloyA 560/A 560M Specification for Castings, C
13、hromium-Nickel AlloyA 609/A 609M Practice for Castings, Carbon, Low-Alloy,and Martensitic Stainless Steel, Ultrasonic ExaminationThereofA 732/A 732M Specification for Castings, Investment, Car-bon and Low Alloy Steel for General Application, andCobalt Alloy for High Strength at Elevated Temperatures
14、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 on Castings.Current edition approved March 1, 2008. Published April 2008. Originallyapproved in 1996. Last previous edition approved
15、in 2006 as A 957 06.2For 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.1*A Summary of Changes section appears at
16、 the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.A 743/A 743M Specification for Castings, Iron-Chromium,Iron-Chromium-Nickel, Corrosion Resistant, for GeneralApplicationA 744/A 744M Specification for Castings,
17、 Iron-Chromium-Nickel, Corrosion Resistant, for Severe ServiceA 747/A 747M Specification for Steel Castings, Stainless,Precipitation HardeningA 751 Test Methods, Practices, and Terminology forChemical Analysis of Steel ProductsA 800/A 800M Practice for Steel Casting, Austenitic Alloy,Estimating Ferr
18、ite Content ThereofA 890/A 890M Specification for Castings, Iron-Chromium-Nickel-Molybdenum Corrosion-Resistant, Duplex(Austenitic/Ferritic) for General ApplicationA 903/A 903M Specification for Steel Castings, SurfaceAcceptance Standards, Magnetic Particle and Liquid Pen-etrant InspectionA 915/A 91
19、5M Specification for Steel Castings, Carbon,and Alloy, Chemical Requirements Similar to StandardWrought GradesA 941 Terminology Relating to Steel, Stainless Steel, Re-lated Alloys, and FerroalloysA 991/A 991M Test Method for Conducting TemperatureUniformity Surveys of Furnaces Used to Heat Treat Ste
20、elProductsA 997 Practice for Investment Castings, Surface Accep-tance Standards, Visual ExaminationE29 Practice for Using Significant Digits in Test Data toDetermine Conformance with SpecificationsE94 Guide for Radiographic ExaminationE 125 Reference Photographs for Magnetic Particle Indica-tions on
21、 Ferrous CastingsE 165 Test Method for Liquid Penetrant ExaminationE 186 Reference Radiographs for Heavy-Walled (2 to 412in. 51 to 114-mm) Steel CastingsE 192 Reference Radiographs of Investment Steel Castingsfor Aerospace ApplicationsE 280 Reference Radiographs for Heavy-Walled (412 to12-in. 114 to
22、 305-mm) Steel CastingsE 353 Test Methods for Chemical Analysis of Stainless,Heat-Resisting, Maraging, and Other Similar Chromium-Nickel-Iron AlloysE 354 Test Methods for Chemical Analysis of High-Temperature, Electrical, Magnetic, and Other Similar Iron,Nickel, and Cobalt AlloysE 446 Reference Radi
23、ographs for Steel Castings Up to 2 in.51 mm in ThicknessE 709 Guide for Magnetic Particle Examination2.2 SAE Aerospace Recommended Practice:3ARP 1341 Determining Decarburization and Carburizationin Finished Parts of Carbon and Low-Alloy Steel3. Terminology3.1 DefinitionsThe definitions in Test Metho
24、ds and Defi-nitions A 370, Test Methods, Practices, and TerminologyA 751, and Terminology A 941 are applicable to this specifi-cation and to those listed in 1.1.3.2 Definitions of Terms Specific to This Standard:3.2.1 investment casting, na metal casting that is pro-duced in a mold obtained by inves
25、ting (surrounding) anexpendable pattern with a ceramic slurry that is allowed tosolidify. The expendable pattern may consist of wax, plastic, orother material and is removed prior to filling the mold withliquid metal.3.2.2 master heat, na quantity of metal processed in asingle furnace or refining ve
26、ssel at one time in such a manneras to produce the desired composition and properties.3.2.3 sub-heat, na portion of a master heat remeltedwithout additional processing for pouring into castings. Syn-onyms: melt, production heat.4. Materials and Manufacture4.1 Melting ProcessMaster heats shall be mad
27、e by theelectric furnace process with or without separate refining suchas argon-oxygen-decarburization (AOD), vacuum-oxygen-degassing (VOD), vacuum-induction-melting (VIM), and soforth, unless otherwise specified in the individual specificationor agreed upon between the customer and producer. Master
28、heats may be used directly for producing castings or convertedinto ingot, bar, shot, or other suitable form, not including gatesand risers from casting production, for later remelting as asub-heat.4.2 Re-Melting ProcessSub-heats shall be produced frommaster heat metal in suitable batch sizes by elec
29、tric inductionfurnace with or without atmosphere protection such as vacuumor inert gas unless otherwise specified in the individualspecification or agreed upon between the customer and pro-ducer. Revert (gates, sprues, risers, and rejected castings) shallnot be re-melted except in master heats.4.3 S
30、ampling:4.3.1 If castings are poured directly from one or moremaster heats, then the samples for chemical and other requiredtesting shall also be poured directly from each of the masterheats.4.3.2 If castings are poured from a sub-heat, then thesamples for chemical and other required testing shall a
31、lso bepoured from a sub-heat of that same master heat, but notnecessarily from the same sub-heat as the castings. The3Available from Society of Automotive Engineers (SAE), 400 CommonwealthDr., Warrendale, PA 15096-0001, http:/www.sae.org.A 957/A 957M 082sub-heat used for the test samples shall be pr
32、oduced using thesame practices and additions as used for the castings.4.3.3 Unless otherwise specified by the purchaser, testspecimens may be taken from castings or from coupons castintegrally with the castings, in the same molds as the castings,or in separate molds.4.4 Heat Treatment:4.4.1 Castings
33、 shall be heat treated in the working zone of afurnace that has been surveyed in accordance with Test MethodA 991/A 991M.4.4.2 When castings are heat treated at temperatures above2000F (1100C), then the working zone shall have beenestablished by a survey performed at not more than 25F(15C) below nor
34、 more than 200F (110C) above the mini-mum heat treatment temperature specified for the grade. If aminimum heat treatment temperature is not specified for thegrade, then the survey temperature shall be not more than 50F(30C) below nor more than 175F (100C) above the furnaceset point used.4.4.3 The ma
35、ximum variation in measured temperature asdetermined by the difference between the highest temperatureand the lowest temperature shall be as agreed between thepurchaser and producer except that during production heattreatment, no portion of the furnace shall be below theminimum specified temperature
36、 nor above the maximumspecified temperature for the grade being processed.5. Chemical Composition5.1 Chemical AnalysisChemical analysis of materialscovered by this specification shall be in accordance with TestMethods, Practices, and Terminology A 751.5.2 Heat AnalysisAn analysis of samples obtained
37、 inaccordance with 4.3 or Supplementary Requirement S17 asappropriate, shall be made by the manufacturer to determinethe percentages of the elements specified in the individualspecification for the grade being poured. When drillings areused, they shall be taken not less than116 in. 1.6 mm beneaththe
38、 surface. The chemical composition thus determined shallconform to the requirements in the individual specification forthe grade being poured.5.3 Product AnalysisA product analysis may be made bythe purchaser from material representing each master heat,sub-heat, lot, or casting. The analysis shall b
39、e made onrepresentative material. Samples for carbon analysis of carbonand alloy steel shall be taken no closer than116 in. 1.6 mm toa cast surface, except that castings too thin for this shall beanalyzed on representative material. The chemical compositionthus determined shall meet the requirements
40、 specified in theapplicable specification for the grade involved, or shall besubject to rejection by the purchaser, except that the chemicalcomposition determined for carbon and low alloy steel castingsmay vary from the specified limits by the amounts shown inTable 1. The product analysis tolerances
41、 of Table 1 are notapplicable as acceptance criteria for heat analysis by thecasting manufacturer. When comparing product and heatanalysis for other than carbon and low alloy steels, thereproducibility Data R2, in Test Methods E 353 or E 354,asapplicable, shall be taken into consideration.5.4 Unspec
42、ified ElementsWhen chemical analysis for el-ements not specified for the grade ordered is desired, Supple-mentary Requirement S13 may be specified.NOTE 1All commercial metals contain small amounts of variouselements in addition to those that are specified. It is neither practical nornecessary to spe
43、cify limits for every unspecified element that might bepresent, despite the fact that the presence of many of these elements isoften routinely determined by the producer.5.5 The substitution of a grade or composition differentfrom that specified by the purchaser is prohibited.6. Mechanical Requireme
44、nts6.1 The individual product specifications vary as to whethermechanical tests are required; for this reason, and to determinespecific test requirements, the individual product specificationshould be reviewed. If mechanical testing is required by theproduct specification, sampling shall be in accor
45、dance with 4.3or with Supplementary Requirement S18 as appropriate.6.2 Unless otherwise specified by the purchaser, whenmechanical properties are required by the product specifica-tion, test coupons may be taken from castings, may be castintegrally with the castings, or may be cast in separate molds
46、 ofthe same type and material as those used for the castings, inaccordance with Fig. 1, Fig. 2, Fig. 3,orFig. 4, except whenSupplementary Requirement S15 is specified. The test couponTABLE 1 Product Analysis TolerancesElement Range, %ATolerancesB,COverMaximum or UnderMinimum Limit, %C up to 0.65 0.0
47、3 3 %CL+ 0.02above 0.65 0.04Mn up to 1 0.08 3 %MnL+ 0.01above 1 0.09Si up to 0.60 0.22 3 %SiL 0.01above 0.60 0.15P all 0.13 3 %PL+ 0.005S all 0.36 3 %SL+ 0.001Ni up to 2 0.10 3 %NiL+ 0.03above 2 0.25Cr up to 2 0.07 3 %CrL+ 0.04above 2 0.18Mo up to 0.6 0.04 3 %MoL+ 0.03above 0.6 0.06V up to 0.25 0.23
48、 3 %VL+ 0.004above 0.25 0.06W up to 0.10 0.08 3 %WL+ 0.02above 0.10 0.02Cu up to 0.15 0.18 3 %CuL+ 0.02above 0.15 0.05Al up to 0.10 0.08 3 %AlL+ 0.02above 0.10 0.03AThe range denotes the composition limits up to which tolerances are computedby the equation, and above which the tolerances are given b
49、y a constant.BThe subscript L for the elements in each equation indicates that the limits ofthe element specified by the applicable specification are to be inserted into theequation to calculate the tolerance for the upper limit and the lower limit (ifapplicable), respectively. Examples of computing tolerances are presented infootnote C.CTo illustrate the computation of the tolerance, consider the manganesemaximum of 0.70 for an 0.30 carbon grade 65-35 in SpecificationA 27/A 27M. Themaximum permissible deviation is (0.08 3 0.70 + 0.01) = 0.066. Th
