ASTM_A_646_-_A_646M_-_06_2016.pdf

Designation:A646/A646M06(Reapproved 2016)Standard Specification forPremium Quality Alloy Steel Blooms and Billets for Aircraftand Aerospace Forgings1This standard is issued under the fixed designation A646/A646M;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.1.Scope*1.1 This specification covers premium quality alloy steelsemifinished rolled or forged blooms and billets for reforginginto critical parts such as aircraft landing-gear forgings.1.2 Blooms and billets,hereinafter referred to as blooms,are semifinished steel products,hot rolled or forged to approxi-mate cross-sectional dimensions.Blooms may be square,round,hexagonal,octagonal,or rectangular in section.For thepurposes of this specification,minimum bloom section sizewill be 16 in.2103 cm2.1.3 This specification covers two basic classifications ofsteel:1.3.1 Class IVacuum-induction melted or consumable-electrode vacuum melted,or other suitable processes whichwill satisfy the quality requirements of this specification.1.3.2 Class IIAir-melted vacuum degassed.1.3.3 Class IIIAir melted electric furnace ladle refinedand vacuum degassed.1.4 The values stated in either inch-pound or SI(metric)units are to be regarded separately as standards.Within the textand tables,the SI units are shown in brackets.The values statedin each system are not exact equivalents;therefore,eachsystem shall be used independently of the other.Combiningvalues from the two systems may result in nonconformancewith the specification.1.5 Unless the order specifies the applicable“M”specifica-tion the material shall be furnished to the inch-pound units.2.Referenced Documents2.1 ASTM Standards:2A255 Test Methods for Determining Hardenability of SteelA388/A388M Practice for Ultrasonic Examination of SteelForgingsA788/A788M Specification for Steel Forgings,General Re-quirementsA604/A604M Practice for Macroetch Testing of Consum-able Electrode Remelted Steel Bars and BilletsE45 Test Methods for Determining the Inclusion Content ofSteelE114 Practice for Ultrasonic Pulse-Echo Straight-BeamContact TestingE127 Practice for Fabrication and Control of AluminumAlloy Ultrasonic Standard Reference BlocksE214 Practice for Immersed Ultrasonic Testing by the Re-flection Method Using Pulsed Longitudinal Waves(With-drawn 2007)3E381 Method of Macroetch Testing Steel Bars,Billets,Blooms,and Forgings2.2 AMS Standards:4AMS 2300 Steel Cleanliness,Premium-QualityAMS 2301 Steel Cleanliness,Aircraft-QualityAMS 2304 Steel Cleanliness,Special Aircraft-Quality3.Terminology3.1 In addition to the terminology requirements of Specifi-cation A788/A788M,the following terms that are specific tothis specification apply:3.2 Definitions:3.2.1 air-melted vacuum-degassed steelarc-or induction-furnace-melted steel that is vacuum treated immediately priorto or during the operation of pouring the ingot.3.2.2 consumable-electrode vacuum-remelted steelmetalthat has been remelted into a crucible in vacuum from single ormultiple electrodes.3.2.3 electroslag-melted steelmetal that has been remeltedinto a crucible from single or multiple electrodes utilizing anelectrical discharge through molten slag as a source of heat.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 March 1,2016.Published April 2016.Originallyapproved in 1971.Last previous edition approved in 2011 as A646/A646M 06(2011).DOI:10.1520/A0646_A0646M-06R16.2For 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.4Available from SAE International(SAE),400 Commonwealth Dr.,Warrendale,PA 15096,http:/www.sae.org.*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 States1 3.2.3.1 DiscussionFor the purposes of this specificationthe parent heat from which any electrode for remelting by theelectroslag process has been produced shall have been eithermelted under vacuum or vacuum degassed immediately priorto or during pouring of the heat.3.2.4 vacuum induction melted steelmetal that has beenmelted,refined,and poured from an induction furnace operat-ing under vacuum.4.Ordering Information and General Requirements4.1 Material supplied to this specification shall conform tothe requirements of Specification A788/A788M,which out-linesadditionalorderinginformation,manufacturingrequirements,testing and retest