ASTM_A_434_-_A_434M_-_17.pdf

Designation:A434/A434M17Standard Specification forSteel Bars,Alloy,Hot-Wrought or Cold-Finished,Quenchedand Tempered1This standard is issued under the fixed designation A434/A434M;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 hot-wrought and cold-finishedquenched and tempered alloy steel bars.1.2 Hot-wrought bars are available in three strength levelclasses designated BB,BC,and BD,and cold-finished bars intwo strength level classes designated BB and BC.The bars areavailable in the conditions specified in 4.4 subject to the sizelimitations shown.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 independently of the other.Combiningvalues from the two systems may result in non-conformancewith the standard.2.Referenced Documents2.1 ASTM Standards:2A29/A29M Specification for General Requirements for SteelBars,Carbon and Alloy,Hot-WroughtA108 Specification for Steel Bar,Carbon and Alloy,Cold-FinishedA370 Test Methods and Definitions for Mechanical Testingof Steel ProductsE112 Test Methods for Determining Average Grain Size3.Ordering Information3.1 Orders for material under this specification shouldinclude the following information:3.1.1 Quantity(weight or number of pieces),3.1.2 Name of material(heat-treated alloy steel bars),3.1.3 Method of finish(condition)(4.4),3.1.4 Dimensions,including length(if hot-wrought bars arefor cold finishing,the cold-finished size should also bespecified),3.1.5 ASTM designation and date of issue,3.1.6 Chemical composition grade(Section 5),3.1.7 Strength class(Table 1),3.1.8 Test report,if required(Section 11),3.1.9 Supplementary Requirements or Special Require-ments,if required,and3.1.10 End use.NOTE1A typical ordering description is as follows:10 000 lb,Heat-Treated Alloy Steel Bars,Hot Rolled,1.000 in.diameter 10 ft,ASTM A434 dated _,Grade 4140,Class BB,Test Report Required,Motor Shafts.4.Materials and Manufacture4.1 Melting PracticeThe steel shall be made by one ormore of the following primary processes:open-hearth,basic-oxygen,or electric-furnace.The primary melting may incor-porate separate degassing or refining and may be followed bysecondary melting using electroslag remelting or vacuum arcremelting.Where secondary melting is employed,the heatshall be defined as all of the ingots remelted from a singleprimary heat.4.2 DiscardSufficient discard shall be made to securefreedom from injurious piping and undue segregation.4.3 Slow CoolingHot-wrought alloy bars shall,immedi-ately after rolling,be allowed to cool to a temperature belowthe critical range under suitable conditions to prevent injury bytoo rapid cooling.4.4 ConditionBars shall be furnished in one of the follow-ing conditions,as specified by the purchaser.Generally,sizelimits for various methods of processing round bars are:Hot-wrought or hot-wrought descaled912in.241.3 mm,maxCold-drawn18to 4 in.3.2 to 102 mm,inclCold-drawn,ground,and polished18to 4 in.3.2 to 102 mm,inclTurned and polished34to 9 in.19.1 to 229 mm,inclTurned,ground,and polished34to 9 in.19.1 to 229 mm,incl4.5 Heat Treatment:4.5.1 Heat treatment shall include quenching and temperingfor all classes of material.The material shall be uniformly1This specification is under the jurisdiction of ASTM Committee A01 on Steel,Stainless Steel and Related Alloys and is the direct responsibility of SubcommitteeA01.15 on Bars.Current edition approved March 15,2017.Published March 2017.Originallyapproved in 1959.Last previous edition approved in 2015 as A434/A434M 15.DOI:10.1520/A0434_A0434M-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 heated to the austenitizing temperature,soaked for a sufficientlength of time to produce the desired structure(a lot thusheated being known as a“quenching charge”),and quenched ina suitable medium under substantially uniform conditions foreach quenching charge.The