ASTM_A_436_-_84_2015.pdf

Designation:A43684(Reapproved 2015)Standard Specification forAustenitic Gray Iron Castings1This standard is issued under the fixed designation A436;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the U.S.Department of Defense.1.Scope1.1 This specification covers austenitic gray iron castingsthat are used primarily for their resistance to heat,corrosion,and wear.Austenitic gray iron is characterized by uniformlydistributed graphite flakes,some carbides,and the presence ofsufficient alloy content to produce an austenitic structure.1.2 The values stated in inch-pound units are to be regardedas standard.The values given in parentheses are mathematicalconversions to SI units that are provided for information onlyand are not considered standard.2.Referenced Documents2.1 ASTM Standards:2E30 Test Methods for ChemicalAnalysis of Steel,Cast Iron,Open-Hearth Iron,and Wrought Iron(Withdrawn 1995)3E59 Practice for Sampling Steel and Iron for Determinationof Chemical Composition(Withdrawn 1996)3E94 Guide for Radiographic ExaminationE165 Practice for Liquid Penetrant Examination for GeneralIndustryE351 Test Methods for ChemicalAnalysis of Cast IronAllTypesE433 Reference Photographs for Liquid Penetrant Inspec-tionE446 Reference Radiographs for Steel Castings Up to 2 in.(50.8 mm)in Thickness3.Ordering Information3.1 Orders for material to this specification shall include thefollowing information:3.1.1 ASTM designation and date of issue,3.1.2 Type of austenitic gray iron required(see 5.1),3.1.3 Heat treatment required(see 4.2 through 4.5),3.1.4 If repair of castings is permitted(see 4.6),3.1.5 Size and number of test bars required(see 11 through8.4 and 12.1),3.1.6 If special tests are required(see Section 7 and 9.1),3.1.7 If certification is required(see 14.1),and3.1.8 If different preparation for delivery requirements areneeded(see 15.1).4.Materials and Manufacture4.1 Melting may be done in any furnace that producescastings meeting the chemical compositions and mechanicalproperties outlined in this specification.These include cupolas,air furnaces,electric furnaces,crucible furnaces,and so forth.4.2 By agreement between the manufacturer and thepurchaser,the castings may be stress relieved by heating to andholding in the temperature range from 1150 to 1200F(620 to650C)for not less than 1 nor more than 2 h/in.of thickness inthe thickest section.Heating and cooling shall be uniform andshall be not more than 400F(222C)/h for castings less than1 in.in maximum thickness,nor more than 400F/h divided bythe maximum section thickness in inches for thicker castings.During the cooling cycle,castings may be cooled in still airafter the temperature has dropped to 600F(315C).4.3 If the manufacturer can demonstrate that another treat-ment provides satisfactory stress relief,it may be used byagreement between the manufacturer and the purchaser.4.4 Whenever dimensional changes in high-temperatureservice are a problem,by agreement between the manufacturerand the purchaser,the castings may be stabilized by heating at1600F(870C)for 1 h/in.of section,for a minimum of 1 h.Otherwise,the austenite that is supersaturated with respect tocarbon may reject carbon during service and produce dimen-sional changes.4.5 By agreement between the manufacturer and thepurchaser,castings with chilled edges or excessive carbidesmay be annealed at 1750 to 1900F(955 to 1040C)for12to5 h,followed by uniform cooling,preferably in still air.4.6 Castings shall not be repaired by welding,plugging,orother methods without written permission from the purchaser.1This specification is under the jurisdiction of ASTM Committee A04 on IronCastings and is the direct responsibility of Subcommittee A04.01 on Grey and WhiteIron Castings.Current edition approved Nov.1,2015.Published November 2015.Originallyapproved in 1959.Last previous edition approved in 2011 as A43684(2011).DOI:10.1520/A0436-84R15.2For 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.3The last approved version of this historical standard is referenced onwww.astm.org.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 5.Chemical Composition5.1 Many combinations of alloys can be used to obtain anaustenitic gray iron.This specification includes only the sixtypes defined by the chemical composition limits specified inTable 1.5.2 The chemical analysis for total carbon shall be made onchilled cast pencil-type specimens or from thin wafers approxi-mately132in.(0.8 mm)thick cut from test coupons