1、Designation:A897/A897M16Standard Specification forAustempered Ductile Iron Castings1This standard is issued under the fixed designation A897/A897M;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
2、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 ductile iron castings that aresubsequently heat treated by an austempering process asdefined in 9.1.1.2 The application of
3、 the austempering heat treatmentextends the range of properties achievable in ductile ironcastings.1.3 No precise quantitative relationship can be stated be-tween the properties of the iron in various locations of the samecasting or between the properties of castings and those of a testspecimen cast
4、 from the same iron(see Appendix X1).However,austempering heat treatment will tend to diminishany differences in mechanical properties.1.4 The production of castings,machining(if required),andthe austempering heat treatments may be performed by differ-ent manufacturers,as covered in Section 13.The p
5、urchasershould establish by contract agreement,at the time of ordering,the responsibility of the various parties for meeting thespecification requirements.1.5 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
6、exact equivalents;therefore,eachsystem shall be used independently of the other.Combiningvalues from the two systems may result in non-conformancewith the standard.1.5.1 ExceptionWithin the text,the SI units are shown inbrackets.2.Referenced Documents2.1 ASTM Standards:2A247 Test Method for Evaluati
7、ng the Microstructure ofGraphite in Iron CastingsA370 Test Methods and Definitions for Mechanical Testingof Steel ProductsA732/A732M Specification for Castings,Investment,Car-bon and Low Alloy Steel for General Application,andCobalt Alloy for High Strength at Elevated TemperaturesA834 Specification
8、for Common Requirements for IronCastings for General Industrial UseE8 Test Methods for Tension Testing of Metallic MaterialsE10 Test Method for Brinell Hardness of Metallic MaterialsE23 Test Methods for Notched Bar Impact Testing of Me-tallic Materials2.2 Military Standard:MIL-STD-129 Military Marki
9、ng for Shipment and Storage33.Ordering Information3.1 Orders for material to this specification shall include thefollowing information:3.1.1 ASTM designation,with year of issue,3.1.2 Grade of austempered ductile iron required(see Table1 or Table 2 and Section 6),3.1.3 Chemical composition requiremen
10、ts,if any(see Sec-tion 4),3.1.4 Heat treated microstructure restrictions(see Section9),3.1.5 Test coupon criteria(see Section 11),3.1.6 Lot size and tests per lot(see 11.6 and Section 13),3.1.7 Special requirements,if desired,including hardness,radiographic soundness,magnetic particle inspection,pre
11、ssuretightness,dimensions,or surface finish(see Section 8),3.1.8 Certification,if required(see Section 14),3.1.9 Special preparation for delivery,if required(see Sec-tion 15).4.Chemical Composition4.1 Although this specification has no specific chemicalrequirements,such requirements may be agreed up
12、on betweenthe manufacturer,heat treater,and the purchaser.4.2 Castings that are of sufficient quality(5.1 and AppendixX1)and properly alloyed(have sufficient hardenability)for the1This specification is under the jurisdiction of ASTM Committee A04 on IronCastings and is the direct responsibility of S
13、ubcommittee A04.02 on Malleable andDuctile Iron Castings.Current edition approved Aug.1,2016.Published August 2016.Originallyapproved in 1990.Last previous edition approved in 2015 as A897/A897M 15.DOI:10.1520/A0897_A0897M-16.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orconta
14、ct ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.3Available from Standardization Documents Order Desk,DODSSP,Bldg.4,SectionD,700RobbinsAve.,Philadelphia,PA19111-5098,http:/dodssp.daps.dla.m
15、il.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 austempering process can be heat treated to meet the minimumproperties for any of the five grades ofADI listed in Table 1 byproper selection of heat treatment temperatures and times,butma
16、y not be properly alloyed to produce castings meeting theminimum properties listed in Table 2.Alloy requirements forthe mixed microstructure grades of ADI(Table 2)will bedifferent than those for the five grades ofADI listed in Table 1.5.Microstructure5.1 The graphite component of the microstructure shallconsist of a minimum 80%spheroidal graphite conforming toTypes I and II per Test Method A247.5.2 The matrix microstructure shall substantially consist ofausferrite(acicular ferrite and high carbo
