1、Designation:A68108(Reapproved 2015)Standard Specification forTool Steels Alloy1This standard is issued under the fixed designation A681;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
2、 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 the chemical,mechanical,andphysical requirements
3、for available wrought alloy tool steelproducts.1.2 These products,which include hot or cold finished bar,plate,sheet,strip,rod,wire,or forgings,are normally fabri-cated into tools,dies,or fixtures.The selection of a material fora particular application will depend upon design,serviceconditions,and d
4、esired properties.1.3 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:2A370 Test Methods and Defi
5、nitions for Mechanical Testingof Steel ProductsA561 Practice for Macroetch Testing of Tool Steel BarsA600 Specification for Tool Steel High SpeedA700 Guide for Packaging,Marking,and Loading Methodsfor Steel Products for ShipmentE3 Guide for Preparation of Metallographic SpecimensE30 Test Methods for
6、 ChemicalAnalysis of Steel,Cast Iron,Open-Hearth Iron,and Wrought Iron(Withdrawn 1995)3E45 Test Methods for Determining the Inclusion Content ofSteelE59 Practice for Sampling Steel and Iron for Determinationof Chemical Composition(Withdrawn 1996)3E527 Practice for Numbering Metals and Alloys in theU
7、nified Numbering System(UNS)2.2 Military Standard:4MIL-STD-163 Steel Mill Products,Preparation for Ship-ment and Storage2.3 Federal Standards:4Fed.Std.No.123 Marking and Shipment(Civil Agencies)Fed.Std.No.183 Continuous Identification Marking of Ironand Steel Products2.4 Other Standards:5SAE J1086 R
8、ecommended Practice for Numbering Metalsand Alloys(UNS)3.Classification3.1 Material in accordance with this specification is classi-fied by chemical composition.Types correspond to respectiveAISI designations.3.1.1 Hot Work Tool Steels,Identification H:3.1.1.1 Types H10 to H19 are characterized by a
9、 controlledchromium content along with other alloying elements.The firstfour,containing molybdenum,offer excellent toughness andhigh hardenability and are frequently used in cold workapplications requiring toughness at relatively high hardnesslevels.3.1.1.2 Types H21 to H26 are characterized by a co
10、ntrolledtungsten content along with other alloying elements.Thesesteels offer greater resistance to the softening effect of elevatedservice temperatures but exhibit a lower degree of toughness.3.1.1.3 Types H41 to H43 are low-carbon modifications ofmolybdenum high speed tool steels(Note 1)and have c
11、harac-teristics similar to the tungsten types.NOTE1High-speed tool steels are covered in Specification A600.3.1.2 Cold Work Tool Steels,Identification ATypes A2 toA10 cover a wide range of carbon and alloy contents but allhave high hardenability and may be hardened in air.The lowcarbon Types A8 and
12、A9 have less wear resistance but offergreater toughness than others in this group.TypeA7,with high1This specification is under the jurisdiction of ASTM Committee A01 on Steel,Stainless Steel and Related Alloysand is the direct responsibility of SubcommitteeA01.29 on Tool Steels.Current edition appro
13、ved Sept.1,2015.Published September 2015.Originallyapproved in 1973.Last previous edition approved in 2008 as A681 08.DOI:10.1520/A0681-08R15.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume
14、information,refer to the standards Document Summary page onthe ASTM website.3The last approved version of this historical standard is referenced onwww.astm.org.4Available from DLA Document Services,Building 4/D,700 Robbins Ave.,Philadelphia,PA 19111-5094,http:/quicksearch.dla.mil.5Available from SAE
15、 International(SAE),400 Commonwealth Dr.,Warrendale,PA 15096,http:/www.sae.org.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 carbon and vanadium,offers exceptional wear resistance but ata very low level of toughness.3.1.3 Cold Work Tool
16、 Steels,Identification DTypes D2 toD7 are characterized by high carbon and high chromiumcontents and exhibit high resistance to abrasion.The typescontaining molybdenum may be hardened in air and offer ahigh degree of dimensional stability in heat treatment.3.1.4 Cold Work Tool Steels,Identification OTypes O1 toO7 are low-alloy types that must be hardened by quenching inoil.Sizes over about 2 in.(50 mm)in cross section usuallyexhibit lower interior hardness.3.1.5 Shock-Resisting Steels,Identifica
