ASTM_A_668_-_A_668M_-_17.pdf

Designation:A668/A668M17American Association StateHighway and Transportation Officials StandardAASHTO No.:M 102Standard Specification forSteel Forgings,Carbon and Alloy,for General IndustrialUse1This standard is issued under the fixed designation A668/A668M;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 parentheses 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.Scope*1.1 This specification covers untreated and heat-treatedcarbon and alloy steel forgings for general industrial use.OtherASTM specifications for forgings are available for specificapplications such as pressure vessels,railroad use,turbinegenerators,gearing,and others involving special temperaturerequirements.1.2 Hot-rolled or cold finished bars are not within the scopeof this specification.1.3 Six classes of carbon steel and seven classes of alloysteel forgings are listed(see Section 7),which indicates theirrequired heat treatments,as well as mechanical properties.1.4 Provision,with the suffix H for certification andmarking,for the supply of forgings after hardness testing only.1.5 Supplementary requirements,including those in Speci-fication A788/A788M,of an optional nature are provided.These shall apply only when specified by the purchaser.1.6 Appendix X1 lists the current classes corresponding tothe various classes of Specifications A235,A237,and A243,which have been superseded by this specification.1.7 The values stated in either SI units or inch-pound unitsare to be regarded separately as standard;within the text andtables,the SI units are shown in brackets.The values stated ineach system may not be exact equivalents;therefore,eachsystem shall be used independently of the other.Combiningvalues from the two systems may result in nonconformancewith the standard.1.8 UnlesstheorderspecifiestheapplicableMspecification,the forgings shall be furnished to the inch-poundunits.1.9 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade(TBT)Committee.2.Referenced Documents2.1 ASTM Standards:2A275/A275M Practice for Magnetic Particle Examination ofSteel ForgingsA370 Test Methods and Definitions for Mechanical Testingof Steel ProductsA388/A388M Practice for Ultrasonic Examination of SteelForgingsA788/A788M Specification for Steel Forgings,General Re-quirementsE290 Test Methods for Bend Testing of Material for Ductil-ityE340 Practice for Macroetching Metals and Alloys3.Terminology3.1 The terminology section of Specification A788/A788Mis applicable to this specification.3.2 Definitions of Terms Specific to This Standard:3.2.1classa description of steel forgings based on heattreatment,mechanical properties and composition.3.2.2 controlling cross section thickness(TC)the diameterof the largest theoretical sphere which can be inscribed withinthe volume of the forging.3.2.3 TPdesignates prolongations which have a size otherthan the controlling cross section thickness(TC).1This specification is under the jurisdiction of ASTM Committee A01 on Steel,Stainless Steel and Related Alloys and is the direct responsibility of SubcommitteeA01.06 on Steel Forgings and Billets.Current edition approved May 1,2017.Published May 2017.Originallyapproved in 1972.Last previous edition approved in 2016 as A668/A668M-16.DOI:10.1520/A0668_A0668M-17.2For 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.*A Summary of Changes section appears at the end of this standardCopyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade(TBT)Committee.1 4.Ordering Information and General Requirements4.1 Material supplied to this specification shall conform tothe requirements of Specification A788/A788M which outlinesadditional ordering information,manufacturing requirements,testing and retesting methods and procedures,marking,certification,product analysis variations and additional supple-mentary requirements.4.1.1 If the requirements of this specification are in conflictwith the requirements of Specification A788/A788M,therequirements of this specification shall pre