1、Designation: A729/A729M 09 (Reapproved 2014)A729/A729M 15Standard Specification forCarbon and Alloy Steel Axles, Heat-Treated, for Mass Transitand Electric Railway Service1This standard is issued under the fixed designation A729/A729M; the number immediately following the designation indicates the y
2、earof 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 Scope*1.1 This specification covers heat-treated carbon
3、and alloy steel axles for mass transit and commuter cars in electric andlocomotive hauled railway service.1.2 This specification is for solid design roller bearing axles with machined bodies.1.3 Various axle designs are used for this service including motor and non-motor with either inboard or outbo
4、ard journals.1.4 Supplementary requirements including those in the general requirements of Specification A788/A788M are provided for usewhen additional testing or inspection is desired. These shall apply only when specified individually by the purchaser in the order.1.5 Unless the order specifies th
5、e applicable “M” specification designation, the axles shall be furnished to the inch-pound units.1.6 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in eachsystem may not be exact equivalents; therefore, each system shall be used
6、independently of the other. Combining values from thetwo systems may result in non-conformance with the standard.2. Referenced Documents2.1 ASTM Standards:2A29/A29M Specification for General Requirements for Steel Bars, Carbon and Alloy, Hot-WroughtA275/A275M Practice for Magnetic Particle Examinati
7、on of Steel ForgingsA388/A388M Practice for Ultrasonic Examination of Steel ForgingsA788/A788M Specification for Steel Forgings, General RequirementsE112 Test Methods for Determining Average Grain SizeE381 Method of Macroetch Testing Steel Bars, Billets, Blooms, and ForgingsE1426 Test Method for Det
8、ermining the X-Ray Elastic Constants for Use in the Measurement of Residual Stress Using X-RayDiffraction Techniques2.2 Other Standards:3AAR Manual of Standards and Recommended Practices Wheels and Axles3. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 classthe set of chemical r
9、equirements for the steel to be used for the axles to be supplied.3.1.2 gradethe designation of the specific set of mechanical properties selected for the axle(s) to be supplied. The grade isselected based on the axle design and service requirements.3.2 Users of this specification are cautioned that
10、 the above terms may be used differently in other industry standards andpurchaser ordering information. Producers and purchasers should ensure that both parties are in agreement regarding the specificmechanical and chemical requirements for the axles to be supplied.1 This specification is under the
11、jurisdiction ofASTM Committee A01 on Steel, Stainless Steel and RelatedAlloys and is the direct responsibility of Subcommittee A01.06on Steel Forgings and Billets.Current edition approved Oct. 1, 2014May 15, 2015. Published October 2014June 2015. Originally approved in 1976. Last previous edition ap
12、proved in 20092014 asA729/A729M 091.(2014). DOI: 10.1520/A0729_A0729M-09R14.10.1520/A0729_A0729M-15.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Doc
13、ument Summary page on the ASTM website.3 Available from Association of American Railroads (AAR), 425 Third St., SW, Washington, DC 20024, http:/www.aar.org.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made
14、to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.*A Sum
15、mary 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. Ordering Information4.1 Material supplied to this specification shall conform to the requirements of Specification A788/A788
16、M, which outlinesordering information, manufacturing requirements, testing and retesting methods and procedures, marking, certification, productanalysis variations, and additional supplementary requirements.4.1.1 If the requirements of this specification are in conflict with the requirements of Spec
17、ification A788/A788M, then therequirements of this specification shall prevail.4.2 In addition to the ordering information required by Specification A788/A788M, the purchaser should include with theinquiry and order a detailed drawing, sketch or written description of the axle showing complete detai
18、ls pertaining to dimensions,tolerances if more restrictive than those contained in this specification, degree of finish, and location of stamping.4.2.1 Unless the purchaser designates a class in the purchase order or contract, the class used shall be at the producersdiscretion.4.3 Supplementary requ
19、irements, if needed, including any that are appropriate from Specification A788/A788M.5. Chemical Requirements5.1 Chemical CompositionThe steel shall conform to the chemical requirements specified in Table 1.5.2 Seven classes of steel are included in Table 1. Unless otherwise specified by the purcha
20、ser, the choice of steel class to beused for any given axle grade is at the option of the producer.5.3 Classes F, G, and H are referenced in the AAR Manual of Standards and Recommended Practices and as Grades F, G, andH and unspecified element additions to these classes shall be reported.5.4 The pur
21、chaser may use the requirements of Specification A788/A788M for a product analysis.6. Manufacture6.1 Forging PracticeThe axle may be made direct from the ingot or from blooms, the total reduction in cross-sectional areafrom ingot or strand cast blooms to axle forging being not less than 3 to 1, unle
22、ss otherwise specified.6.2 Cooling and Heating:6.2.1 Blooms and ingots shall be reheated for forging in a manner that will prevent internal bursts and overheating.6.2.2 Axles that are heat-treated directly from forging shall be cooled below the transformation temperature to at least and fullytransfo
23、rmed before any reheating operation. The temperature of the axle shall be below 1000F 538C before the start of anyreheating operation.6.3 Heat Treatment:6.3.1 Axles shall be heat-treated in accordance with Table 2.6.3.2 Grades A and F shall be heat-treated by double normalizing, followed by temperin
24、g. After heating to and holding at anappropriate temperature in the austenitic range, the axles shall be cooled in still air to under 500F 260C. They shall then bereheated into the austenitic range to the same or a lower temperature and again air cooled to under 500F 260C.Afurnace chargethus treated
25、 is termed a double normalizing charge. After cooling, the axles are then tempered as in 5.3.46.3.4.6.3.3 All other Grades shall be liquid quenched and tempered.After heating to and holding at an appropriate temperature in theaustenitic range, the axles shall be quenched in a suitable medium. A furn
26、ace charge thus treated is termed a quenching charge.Following quenching, the axles are tempered as in 5.3.46.3.4.6.3.3.1 Grade H axles require a normalizing cycle prior to the quenching heat treatment.TABLE 1 Chemical RequirementsComposition %Class A Class B Class C Class DA Class F Classes G in th
27、e case of motor axles having a conglomerate of diameters for the seats for wheel, gear, gear case bearing,and grounding ring the entire area shall be rough machined to a single diameter 18 to 14 in. 3.2 to 6.4 mm over the finisheddiameter of the segment having the largest diameter. Longitudinally 18
28、 to 14 in. 3.2 to 6.4 mm of metal shall be allowed at eachchange of cross section for finish machining.11.1.6 The smooth-machined body shall be to the specified size with no more than 18 in. 3.2 mm over on the diameters andshall have no more than 18 in. 3.2 mm allowance longitudinally at each change
29、 of cross section.12. Workmanship and Finish12.1 Axles shall conform to the size, shape, and finish shown on the purchasers drawing and unless otherwise specified shallhave center holes with clearance drilled for lathe center points and not counter bored.All machining shall be done in a workmanlikem
30、anner.A729/A729M 15512.2 Where a smooth-machined finish on the body (10.1.611.1.6) is specified, it shall be to a maximum of 250 in. 6.35 m.Rough machining shall be free of excessively rough ridges and coarse chatter marks.12.3 Finish machined axle surfaces shall be free of injurious imperfections a
31、s defined in Annex A1.13. Product Marking13.1 In addition to the marking requirements of Specification A788/A788M, axles shall be legibly cold-stamped with letters andfigures not less than 14 in. 6.4 mm high. This stamping shall be on the end face or under cut shoulder at the end of the journalas sh
32、own on the purchasers drawing. It should include month and year made, manufacturers name or trademark, heat number,and serial number.13.2 In addition to the above required markings, bar code tags may be applied to the axles. If these tags are applied, it isrecommended that Bar Code 39 for 1-D bar co
33、de labels or AAR S-920 for 2-D bar code labels be used. The size and location ofthe tags, as well as the information to be included, shall be agreed upon by the purchaser and the manufacturer.14. Keywords14.1 axles; rail applications; steel forgingsSUPPLEMENTARY REQUIREMENTSThe following supplementa
34、ry requirement shall apply only when specified by the purchaser. Detailsshall be agreed upon by the manufacturer and the purchaser.S1. Macroscopical TestsS1.1 The prolongation from the largest axle in each heat shall be sawed normal to the axis of the axle and shall then be splitlongitudinally. The
35、transverse and the longitudinal faces shall be etched for macro examination in accordance with Method E381.S1.2 Acceptance criteria shall be based on the adjuncts of Method E381 as specified in the purchase order.S2. Accelerated Cooling after Stress ReliefS2.1 When specified, the rough machined axle
36、 shall be given a sub-critical quench from a temperature above 900F 480C.Sufficient allowance shall be left in the rough machined billet so that the axle can be machined to final dimensions after sub-criticalquench.S3. Residual Stress MeasurementS3.1 When specified, feethe residual compressive stres
37、ses shall be measured in the body section of one representative axle.X-ray diffraction residual stress measurements to Test Method E1426 shall be considered the standard method.S3.2 The results shall be reported.ANNEX(Mandatory Information)A1. INTERPRETATION OF IMPERFECTIONS CONSIDERED INJURIOUS IN
38、AXLESA1.1 GeneralA1.1.1 The conditions that have been most difficult for inspectors to evaluate are light lines visible to the normal unaided eye,variously described as actual seams, hairlines, stringers, shadow seams, ghost lines, and so forth, which appear after the axles havebeen finish machined
39、and burnished or ground. It is, therefore, advisable to describe these conditions in more detail.A729/A729M 156A1.1.2 The interpretation of injurious imperfections as enumerated below is not to be considered as precluding other unforeseenor objectionable conditions not specifically listed. The right
40、 of the purchaser is reserved to reject temporarily such axles and makefinal settlement on the basis of further negotiations between representatives of the manufacturer and the purchaser who areespecially qualified to decide such questions.A1.1.3 Any transverse or circumferential seams, cracks, or l
41、aps of indeterminate depth on the axle surfaces other than thediscolorations listed in A1.1.4 regardless of their location, are considered to be injurious and are cause for rejection without furthermachining.A1.1.4 Ghost lines, shadow marks, or other similar discolorations, visible to the normal una
42、ided eye that are not actual separationsin the metal are not considered injurious regardless of location.A1.1.5 Any longitudinal discontinuity, variously termed hairline, stringer, or fine seam, in machined fillets is considered to beinjurious and is cause for rejection without further conditioning.
43、A1.2 Journals and Dust GuardsA1.2.1 Fine longitudinal discontinuities on the finished (burnished or ground) surfaces variously termed hairlines, stringers, or fineseams are not considered injurious if they meet the following conditions:A1.2.1.1 Must not extend into fillets.A1.2.1.2 Must not be over
44、34 in. 20 mm long individually in the journal nor 12 in. 12.7 mm long individually in the dust-guardseat.A1.2.1.3 Total length of such imperfections over 14 in. 6.4 mm long must not exceed 2 in. 50.8 mm in any one end of the axle.A1.3 Wheel Seats, Gear Seats, Gear Case Bearing Seat, and Grounding Ri
45、ng SeatsA1.3.1 Longitudinal discontinuities on the finished-machined surface of wheel and gear seats, variously termed hairlines,stringers, fine seams, tight seams, surface imperfections, and so forth, are not considered injurious if they meet the followingconditions:A1.3.1.1 Must not extend within
46、112 in. 38.1 mm of either end of the seats covered in this section.A1.3.1.2 Must not be over 12 in. 12.7 mm long individually.A1.3.1.3 Total length of such imperfections, 14 in. 6.4 mm to 12 in. 12.7 mm long, must not exceed 3 in. 76.2 mm in any oneend of the axle.A1.4 Areas Between Attachment Seats
47、 (Body) Specified to Be Smooth MachinedA1.4.1 Longitudinal discontinuities on the smooth machined body, variously termed hairlines, stringers, or fine seams, are notconsidered injurious if they meet the following conditions:A1.4.1.1 Must not extend into fillets at the ends of the body,A1.4.1.2 Must
48、not be over 12 in. 12.7 mm long individually,A1.4.1.3 Total length of such imperfections, 14 in. 6.4 mm to 12 in. 12.7 mm long, must not exceed 112 in. 38.1 mm in any12 in. 305 mm of body length, andA729/A729M 157A1.4.1.4 Axles containing longitudinal discontinuities in the body in excess of those d
49、escribed in A1.4.1.2 and A1.4.1.3 may bereconditioned by grinding or machining provided the diameter is not reduced below the specified minimum.APPENDIX(Nonmandatory Information)X1. COMPOSITIONS FOR AXLE APPLICATIONSX1.1 For the guidance of the purchaser, typical standard compositions that cloudcould be used for axle applications are listedbelow, however the diameter of the axle at the time of heat treatment must be taken into account when selecting the forgingcomposition.A729/A729M 158Grad
