1、Designation:A439/A439M15Standard Specification forAustenitic Ductile Iron Castings1This standard is issued under the fixed designation A439/A439M;the number immediately following the designation indicates the yearof original adoption or,in the case of revision,the year of last revision.A number in p
2、arentheses indicates the year of last reapproval.A superscript 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 ductile iron castings,which
3、 are used primarily for their resistance to heat,corrosion,and wear,and for other special purposes.1.2 Austenitic ductile iron,also known as austenitic nodulariron or austenitic spheroidal iron,is characterized by having itsgraphite substantially in a spheroidal form and substantiallyfree of flake g
4、raphite.It contains some carbides and sufficientalloy content to produce an austenitic structure.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;therefore,eachsystem shall be used indep
5、endently of the other.Combiningvalues from the two systems may result in non-conformancewith the standard.2.Referenced Documents2.1 ASTM Standards:2A247 Test Method for Evaluating the Microstructure ofGraphite in Iron CastingsA370 Test Methods and Definitions for Mechanical Testingof Steel ProductsE
6、8 Test Methods for Tension Testing of Metallic MaterialsE10 Test Method for Brinell Hardness of Metallic MaterialsE30 Methods for Chemical Analysis of Ferroalloys3E59 Practice for Sampling Steel and Iron for Determinationof Chemical Composition3E351 Test Methods for ChemicalAnalysis of Cast IronAllT
7、ypes3.Ordering Information3.1 Orders for material to this specification shall include thefollowing information:3.1.1 ASTM designation,3.1.2 Type of austenitic ductile iron required(see 6.1),3.1.3 Heat treatment options(see 4.3 4.6),3.1.4 If repair of castings is permitted(see 4.7),3.1.5 Size and num
8、ber of test bars required(see 9.1 9.4and 10.1),3.1.6 Special tests,if required(see 12.1),3.1.7 Certification,if required(see 14.1),and3.1.8 Different preparation for delivery requirements,ifneeded(see 15.1).4.Manufacture4.1 Melting may be done in any furnaces that producecastings meeting the chemica
9、l and mechanical requirementsoutlined in this specification.These include cupolas,airfurnaces,electric furnaces,crucible furnaces,and so forth.Nodularizing and inoculation practice shall be optional withthe foundry to produce a microstructure in accordance with 1.2and Test Method A247.4.2 Austenitic
10、 ductile iron castings may be supplied ineither the as-cast or the heat-treated condition.4.3 By agreement between the manufacturer and thepurchaser,the castings may be stress relieved by heating to1150 to 1200F 620 to 650C for not less than 1 h and not formore than 2 h per inch 25 mm of thickness i
11、n the thickestsection.Heating and cooling shall be uniform and shall not bemore than 400F/h 220C/h for castings less than 1 inch25 mm in maximum thickness and shall be not more than400F/h 220C/h divided by the maximum section thicknessin inches 25 mm for thicker castings.During the coolingcycle,cast
12、ings may be cooled in still air after the temperaturehas dropped to 600F 310C.4.4 By agreement between the manufacturer and thepurchaser,the castings may be in-mold stress relieved byallowing castings to cool slowly in the mold at a rate notexceeding 400F/h 220C/h.Once the temperature hasdropped bel
13、ow 600F 310C,castings can be removed fromthe mold and cooled in still air.1This specification is under the jurisdiction of ASTM Committee A04 on IronCastings and is the direct responsibility of Subcommittee A04.02 on Malleable andDuctile Iron Castings.Current edition approved Nov.1,2015.Published De
14、cember 2015.Originallyapproved in 1960.Last previous edition approved in 2009 as A439 83(2009).DOI:10.1520/A0439_A0439M-15.2For 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 t
15、o the standards Document Summary page onthe ASTM website.3Withdrawn.The last approved version of this historical standard is referencedon www.astm.org.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 4.5 Whenever dimensional changes in hig
16、h-temperatureservice are a problem,by agreement between the manufacturerand the purchaser,the castings may be stabilized by heating at1600F 870C for a period of 1 h per inch 25 mm of section,with a minimum period of 1 hour,followed by uniformcooling,preferably in still air.Otherwise,the austenite,whichis super-saturated with respect to carbon,can reject carbonduring service and produce dimensional changes.4.6 By agreement between the manufacturer and thepurchaser,castings with chilled edges or e
