1、Designation: A729/A729M 09 (Reapproved 2014)Standard Specification forAlloy Steel Axles, Heat-Treated, for Mass Transit andElectric Railway Service1This standard is issued under the fixed designation A729/A729M; the number immediately following the designation indicates the yearof original adoption
2、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. Scope1.1 This specification covers heat-treated alloy steel axlesfor mass transit and
3、commuter cars in electric and locomotivehauled railway service.1.2 This specification is for solid design roller bearing axleswith machined bodies.1.3 Various axle designs are used for this service includingmotor and non-motor with either inboard or outboard journals.1.4 Supplementary requirements i
4、ncluding those in the gen-eral requirements of Specification A788/A788M are providedfor use when additional testing or inspection is desired. Theseshall apply only when specified individually by the purchaserin the order.1.5 Unless the order specifies the applicable “M” specifica-tion designation, t
5、he axles shall be furnished to the inch-poundunits.1.6 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
6、 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-WroughtA275/A275M Practice for Magnetic Particle Examination ofSteel ForgingsA388/A388M Practice for Ultraso
7、nic Examination of SteelForgingsA788/A788M Specification for Steel Forgings, General Re-quirementsE112 Test Methods for Determining Average Grain SizeE381 Method of Macroetch Testing Steel Bars, Billets,Blooms, and ForgingsE1426 Test Method for Determining the Effective ElasticParameter for X-Ray Di
8、ffraction Measurements of Re-sidual Stress2.2 Other Standards:AAR Manual of Standards and Recommended Prac-tices Wheels and Axles33. Ordering Information3.1 Material supplied to this specification shall conform tothe requirements of Specification A788/A788M, which out-lines ordering information, man
9、ufacturing requirements, test-ing and retesting methods and procedures, marking,certification, product analysis variations, and additional supple-mentary requirements.3.1.1 If the requirements of this specification are in conflictwith the requirements of Specification A788/A788M, then therequirement
10、s of this specification shall prevail.3.2 In addition to the ordering information required bySpecification A788/A788M, the purchaser should include withthe inquiry and order a detailed drawing, sketch or writtendescription of the axle showing complete details pertaining todimensions, tolerances if m
11、ore restrictive than those containedin this specification, degree of finish, and location of stamping.3.2.1 Unless the purchaser designates a class in the purchaseorder or contract, the class used shall be at the producersdiscretion.3.3 Supplementary requirements, if needed, including anythat are ap
12、propriate from Specification A788/A788M.4. Chemical Requirements4.1 Chemical CompositionThe steel shall conform to thechemical requirements specified in Table 1.1This specification is under the jurisdiction of ASTM Committee A01 on Steel,Stainless Steel and Related Alloys and is the direct responsib
13、ility of SubcommitteeA01.06 on Steel Forgings and Billets.Current edition approved Oct. 1, 2014. Published October 2014. Originallyapproved in 1976. Last previous edition approved in 2009 as A729/A729M 091.DOI: 10.1520/A0729_A0729M-09R14.2For referenced ASTM standards, visit the ASTM website, www.as
14、tm.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 from Association of American Railroads (AAR), 425 Third St., SW,Washington, DC 20024, http:/www.aar.org.*A Summa
15、ry 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 States14.2 Seven classes of steel are included in Table 1. Unlessotherwise specified by the purchaser, the choice of steel class tobe us
16、ed for any given axle grade is at the option of theproducer.4.3 Classes F, G, and H are referenced in the AAR Manualof Standards and Recommended Practices and unspecifiedelement additions to these classes shall be reported.4.4 The purchaser may use the requirements of Specifica-tion A788/A788M for a
17、 product analysis.5. Manufacture5.1 Forging PracticeThe axle may be made direct fromthe ingot or from blooms, the total reduction in cross-sectionalarea from ingot or strand cast blooms to axle forging being notless than 3 to 1, unless otherwise specified.5.2 Cooling and Heating:5.2.1 Blooms shall b
18、e reheated for forging in a manner thatwill prevent internal bursts and overheating.5.2.2 Axles that are heat-treated directly from forging shallbe cooled below the transformation temperature to at least1000F 538C before any reheating operation.5.3 Heat Treatment:5.3.1 Axles shall be heat-treated in
19、 accordance with Table 2.5.3.2 Grades A and F shall be heat-treated by doublenormalizing, followed by tempering. After heating to andholding at an appropriate temperature in the austenitic range,the axles shall be cooled in still air to under 500F 260C.They shall then be reheated into the austenitic
20、 range to thesame or a lower temperature and again air cooled to under500F 260C. A furnace charge thus treated is termed adouble normalizing charge. After cooling, the axles are thentempered as in 5.3.4.5.3.3 All other Grades shall be liquid quenched and tem-pered. After heating to and holding at an
21、 appropriate tempera-ture in the austenitic range, the axles shall be quenched in asuitable medium. A furnace charge thus treated is termed aquenching charge. Following quenching, the axles are tem-pered as in 5.3.4.5.3.3.1 Grade H axles require a normalizing cycle prior tothe quenching heat treatme
22、nt.5.3.3.2 At the manufacturers option for Grade G, a normal-izing cycle may precede austenitizing for the liquid quenchingoperation.5.3.4 TemperingAxles shall be reheated gradually to andheld at an appropriate subcritical temperature, and shall then beallowed to cool under uniform conditions. A fur
23、nace chargethus treated is termed a tempering charge.TABLE 1 Chemical RequirementsComposition %Class A Class B Class C Class DAClass F ClassesG in the case of motor axleshaving a conglomerate of diameters for the seats for wheel,gear, gear case bearing, and grounding ring the entire area shallFIG. 2
24、 Location of Reference Holes in an AxleFlat Bottom Hole Sizes for a Heat-Treated AxleA729/A729M 09 (2014)4be rough machined to a single diameter18 to14 in. 3.2 to6.4 mm over the finished diameter of the segment having thelargest diameter. Longitudinally18 to14 in. 3.2 to 6.4 mm ofmetal shall be allo
25、wed at each change of cross section for finishmachining.10.1.6 The smooth-machined body shall be to the specifiedsize with no more than18 in. 3.2 mm over on the diametersand shall have no more than18 in. 3.2 mm allowancelongitudinally at each change of cross section.11. Workmanship and Finish11.1 Ax
26、les shall conform to the size, shape, and finishshown on the purchasers drawing and unless otherwisespecified shall have center holes with clearance drilled for lathecenter points and not counter bored. All machining shall bedone in a workmanlike manner.11.2 Where a smooth-machined finish on the bod
27、y (10.1.6)is specified, it shall be to a maximum of 250 in. 6.35 m.Rough machining shall be free of excessively rough ridges andcoarse chatter marks.11.3 Finish machined axle surfaces shall be free of injuriousimperfections as defined in Annex A1.12. Product Marking12.1 In addition to the marking re
28、quirements of Specifica-tion A788/A788M, axles shall be legibly cold-stamped withletters and figures not less than14 in. 6.4 mm high. Thisstamping shall be on the end face or under cut shoulder at theend of the journal as shown on the purchasers drawing. Itshould include month and year made, manufac
29、turers name ortrademark, heat number, and serial number.12.2 In addition to the above required markings, bar codetags may be applied to the axles. If these tags are applied, it isrecommended that Bar Code 39 be used. The size and locationof the tags, as well as the information to be included, shall
30、beagreed upon by the purchaser and the manufacturer.13. Keywords13.1 axles; rail applications; steel forgingsSUPPLEMENTARY REQUIREMENTSThe following supplementary requirement shall apply only when specified by the purchaser. Detailsshall be agreed upon by the manufacturer and the purchaser.S1. Macro
31、scopical TestsS1.1 The prolongation from the largest axle in each heatshall be sawed normal to the axis of the axle and shall then besplit longitudinally. The transverse and the longitudinal facesshall be etched for macro examination in accordance withMethod E381.S1.2 Acceptance criteria shall be ba
32、sed on the adjuncts ofMethod E381 as specified in the purchase order.S2. Accelerated Cooling after Stress ReliefS2.1 When specified, the rough machined axle shall begiven a sub-critical quench from a temperature above 900F480C. Sufficient allowance shall be left in the rough ma-chined billet so that
33、 the axle can be machined to finaldimensions after sub-critical quench.S3. Residual Stress MeasurementS3.1 When specified, fee residual compressive stresses shallbe measured in the body section of one representative axle.X-ray diffraction residual stress measurements to Test MethodE1426 shall be con
34、sidered the standard method.S3.2 The results shall be reported.ANNEX(Mandatory Information)A1. INTERPRETATION OF IMPERFECTIONS CONSIDERED INJURIOUS IN AXLESA1.1 GeneralA1.1.1 The conditions that have been most difficult forinspectors to evaluate are light lines visible to the normalunaided eye, vari
35、ously described as actual seams, hairlines,stringers, shadow seams, ghost lines, and so forth, whichappear after the axles have been finish machined and burnishedor ground. It is, therefore, advisable to describe these condi-tions in more detail.A1.1.2 The interpretation of injurious imperfections a
36、s enu-merated below is not to be considered as precluding otherunforeseen or objectionable conditions not specifically listed.The right of the purchaser is reserved to reject temporarily suchaxles and make final settlement on the basis of furthernegotiations between representatives of the manufactur
37、er andthe purchaser who are especially qualified to decide suchquestions.A729/A729M 09 (2014)5A1.1.3 Any transverse or circumferential seams, cracks, orlaps of indeterminate depth on the axle surfaces other than thediscolorations listed in A1.1.4 regardless of their location, areconsidered to be inj
38、urious and are cause for rejection withoutfurther machining.A1.1.4 Ghost lines, shadow marks, or other similardiscolorations, visible to the normal unaided eye that are notactual separations in the metal are not considered injuriousregardless of location.A1.1.5 Any longitudinal discontinuity, variou
39、sly termedhairline, stringer, or fine seam, in machined fillets is consideredto be injurious and is cause for rejection without furtherconditioning.A1.2 Journals and Dust GuardsA1.2.1 Fine longitudinal discontinuities on the finished(burnished or ground) surfaces variously termed hairlines,stringers
40、, or fine seams are not considered injurious if theymeet the following conditions:A1.2.1.1 Must not extend into fillets.A1.2.1.2 Must not be over34 in. 20 mm long individuallyin the journal nor12 in. 12.7 mm long individually in thedust-guard seat.A1.2.1.3 Total length of such imperfections over14 i
41、n.6.4 mm long must not exceed 2 in. 50.8 mm in any one endof the axle.A1.3 Wheel Seats, Gear Seats, Gear Case Bearing Seat,and Grounding Ring SeatsA1.3.1 Longitudinal discontinuities on the finished-machined surface of wheel and gear seats, variously termedhairlines, stringers, fine seams, tight sea
42、ms, surfaceimperfections, and so forth, are not considered injurious if theymeet the following conditions:A1.3.1.1 Must not extend within 112 in. 38.1 mm of eitherend of the seats covered in this section.A1.3.1.2 Must not be over12 in. 12.7 mm long individu-ally.A1.3.1.3 Total length of such imperfe
43、ctions,14 in. 6.4 mmto12 in. 12.7 mm long, must not exceed 3 in. 76.2 mm inany one end of the axle.A1.4 Areas Between Attachment Seats (Body) Specified toBe Smooth MachinedA1.4.1 Longitudinal discontinuities on the smooth ma-chined body, variously termed hairlines, stringers, or fineseams, are not c
44、onsidered injurious if they meet the followingconditions:A1.4.1.1 Must not extend into fillets at the ends of the body,A1.4.1.2 Must not be over12 in. 12.7 mm longindividually,A1.4.1.3 Total length of such imperfections,14 in. 6.4 mmto12 in. 12.7 mm long, must not exceed 112 in. 38.1 mm inany 12 in.
45、 305 mm of body length, andA1.4.1.4 Axles containing longitudinal discontinuities inthe body in excess of those described in A1.4.1.2 and A1.4.1.3may be reconditioned by grinding or machining provided thediameter is not reduced below the specified minimum.APPENDIX(Nonmandatory Information)X1. COMPOS
46、ITIONS FOR AXLE APPLICATIONSX1.1 For the guidance of the purchaser, typical standardcompositions that cloud be used for axle applications are listedbelow, however the diameter of the axle at the time of heattreatment must be taken into account when selecting theforging composition.Grade Standard Com
47、positionSpecification A29/A29MB 4130C 4140D 8630ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights,
48、 and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for rev
49、ision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, P
