1、Designation:A4912Standard Specification forHeat-Treated Carbon Steel Joint Bars,Microalloyed JointBars,and Forged Carbon Steel Compromise Joint Bars1This standard is issued under the fixed designationA49;the number immediately following the designation indicates the year of originaladoption or,in th
2、e case of revision,the year of last revision.Anumber in parentheses indicates the year of last reapproval.Asuperscriptepsilon()indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.1.Scope1.1 This specific
3、ation covers heat-treated carbon steel jointbars,microalloyed joint bars,and forged compromise joint barsfor general use in standard railroad track.1.2 The joint bars may be used for the production ofinsulated joints.1.3 The values stated in inch-pound units are to be regardedas the standard.The val
4、ues given in parentheses are forinformation only.2.Referenced Documents2.1 ASTM Standards:2A29/A29M Specification for Steel Bars,Carbon and Alloy,Hot-Wrought,General Requirements forA370 Test Methods and Definitions for Mechanical Testingof Steel ProductsA700 Practices for Packaging,Marking,and Load
5、ing Meth-ods for Steel Products for Shipment2.2 American Railway Engineering and Maintenance ofWay Association Manual for Railway Engineering33.Ordering Information3.1 Orders for joint bars under this specification shallinclude the following information as appropriate:3.1.1 Quantitynumber of pairs o
6、f bars,3.1.2 Typedesign or type bar along with section designa-tion and weight of rails being joined,3.1.3 Dimensionoverall length,3.1.4 Punchingtype(elliptical,oval,round,or combina-tions),size,number,location,spacing and elevation ofpunched holes,with dimensional drawing if necessary,3.1.5 Head Ea
7、sementif required,and3.1.6 Certification and Test Report Requirements(see 12.1).4.Manufacture4.1 The steel shall be made by one or both of the followingprocesses:basic-oxygen or electric-furnace.4.1.1 The steel may be cast by a continuous process,or iningots.4.2 Heating and QuenchingQuenched carbon-
8、steel jointbars and forged compromise joint bars shall be uniformlyheated for punching,slotting,shaping,and forging and subse-quently quenched.Maximum depth of decarburized layer offorged bars shall not exceed 0.040 in.4.3 Microalloyed joint bars shall be produced from hotrolled steel sections.Bars
9、shall be sheared or sawed cold,andholes shall be drilled.No reheating and quenching is required.5.Chemical Requirements5.1 The chemical composition of the quenched carbon-steeljoint bars and forged compromise joint bars determined asprescribed in 5.3 shall be within the limits shown in Table 1.5.2 T
10、he chemical composition of the microalloyed joint barsshall be agreed upon by the purchaser and the manufacturer.Microalloying shall be accomplished with columbium,vana-dium,and nitrogen,or combinations thereof.5.3 Heat or Cast AnalysisSeparate analysis shall be madefrom test samples representing on
11、e of the first three and one ofthe last three ingots or continuously cast blooms preferablytaken during the pouring of the heat.Determinations may bemade chemically or spectrographically.Any portion of the heatmeeting the chemical analysis requirements of Table 1 may beapplied.The first heat analysi
12、s shall be recorded as the officialheat analysis,but the purchaser shall have access to all ladleanalyses.Additionally,any material meeting the product analy-sis limits shown in Table 2 may be applied after testing suchmaterial in accordance with Specification A29/A29M.1This specification is under t
13、he jurisdiction of ASTM Committee A01 on Steel,Stainless Steel and Related Alloys and is the direct responsibility of SubcommitteeA01.01 on Steel Rails and Accessories.Current edition approved March 1,2012.Published April 2012.Originallyapproved in 1915.Last previous edition approved in 2006 as A49
14、01(2006).DOI:10.1520/A0049-12.2For 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.3Available fromAmerican Railway Engi
15、neering and Maintenance of WayAssn.,10003 Derekwood Lane,Suite 210,Lanham,MD 20706.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1Copyright by ASTM Intl(all rights reserved);5.4 Product AnalysisWhen ladle tests are not available,finished
16、material representing the heat may be product tested.The product analysis allowance beyond the limits of thespecified ladle analysis shall be within the limits for productanalyses specified in Table 2.5.4.1 An analysis may be made by the purchaser from asample taken from a finished joint bar representing each heat orcast.The chemical composition thus determined shall conformto the requirements in Table 2.6.Tensile Requirements6.1 Properties:6.1.1 The material as represented by a tension test spe
