ASTM A729/A729M-17(2022)

Standard Specification for Carbon and Alloy Steel Axles, Heat-Treated, for Mass Transit and Electric Railway Service

ABSTRACT
This specification deals with the standard requirements for heat-treated alloy steel axles and solid design roller bearing axles with machined bodies for mass transit and commuter cars in electric and locomotive hauled railway service. Various axle designs are used for this service including motor and non-motor with either inboard or outboard journals. Materials shall be forged, cooled and heat treated by normalizing, liquid quenching, tempering, and straightening. Steels shall conform to chemical composition requirements specified for each of the seven classes considered here. Conformance to mechanical property requirements such as tensile strength, yield strength, elongation, and reduction of area, shall be evaluated by tensile tests. Details of nondestructive ultrasonic and magnetic particle examination procedures are discussed thoroughly. Final axle products shall conform to purchaser-specified size, shape, and finish. Rough machining shall be free of excessively rough ridges and coarse chatter marks, and the finish machined axle surfaces shall be free of injurious imperfections.
SCOPE
1.1 This specification covers heat-treated carbon and alloy steel axles for mass transit and commuter cars in electric and locomotive 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 outboard journals.  
1.4 Supplementary requirements including those in the general requirements of Specification A788/A788M are provided for use when 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 the 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 each system are not necessarily exact equivalents; therefore, to ensure conformance with the standard, each system shall be used independently of the other, and values from the two systems shall not be combined.  
1.7 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 31-Aug-2022
• ICS: 45.040 - Materials and components for railway engineering
• Technical Committee: A01 - Steel, Stainless Steel and Related Alloys
• Drafting Committee: A01.06 - Steel Forgings and Billets

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: A729/A729M −17 (Reapproved 2022)
Standard Specification for
Carbon and Alloy Steel Axles, Heat-Treated, for Mass Transit
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and Electric Railway Service
This standard is issued under the fixed designationA729/A729M; the number immediately following the designation indicates the year
of 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* A29/A29M SpecificationforGeneralRequirementsforSteel
Bars, Carbon and Alloy, Hot-Wrought
1.1 This specification covers heat-treated carbon and alloy
A275/A275M Practice for Magnetic Particle Examination of
steel axles for mass transit and commuter cars in electric and
Steel Forgings
locomotive hauled railway service.
A388/A388M Practice for Ultrasonic Examination of Steel
1.2 This specification is for solid design roller bearing axles
Forgings
with machined bodies.
A788/A788M Specification for Steel Forgings, General Re-
quirements
1.3 Various axle designs are used for this service including
motor and non-motor with either inboard or outboard journals. E112 Test Methods for Determining Average Grain Size
E381 Method of Macroetch Testing Steel Bars, Billets,
1.4 Supplementary requirements including those in the gen-
Blooms, and Forgings
eral requirements of Specification A788/A788M are provided
E1426 Test Method for Determining the X-Ray Elastic
for use when additional testing or inspection is desired. These
Constants for Use in the Measurement of Residual Stress
shall apply only when specified individually by the purchaser
Using X-Ray Diffraction Techniques
in the order.
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2.2 Other Standard:
1.5 Unless the order specifies the applicable “M” specifica-
AAR Manual of Standards and Recommended Prac-
tion designation, the axles shall be furnished to the inch-pound
tices Wheels and Axles, Section G
units.
3. Terminology
1.6 The values stated in either SI units or inch-pound units
are to be regarded separately as standard. The values stated in 3.1 Definitions of Terms Specific to This Standard:
3.1.1 class—the set of chemical requirements for the steel to
each system are not necessarily exact equivalents; therefore, to
ensure conformance with the standard, each system shall be be used for the axles to be supplied.
used independently of the other, and values from the two
3.1.2 grade—the designation of the specific set of mechani-
systems shall not be combined.
cal properties selected for the axle(s) to be supplied. The grade
1.7 This international standard was developed in accor- is selected based on the axle design and service requirements.
dance with internationally recognized principles on standard-
3.2 Users of this specification are cautioned that the above
ization established in the Decision on Principles for the
terms may be used differently in other industry standards and
Development of International Standards, Guides and Recom-
purchaser ordering information. Producers and purchasers
mendations issued by the World Trade Organization Technical
should ensure that both parties are in agreement regarding the
Barriers to Trade (TBT) Committee.
specific mechanical and chemical requirements for the axles to
be supplied.
2. Referenced Documents
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2.1 ASTM Standards: 4. Ordering Information
4.1 Material supplied to this specification shall conform to
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the requirements of Specification A788/A788M, which out-
This specification is under the jurisdiction of ASTM Committee A01 on Steel,
Stainless Steel and Related Alloys and is the direct responsibility of Subcommittee
lines ordering information, manufacturing requirements, test-
A01.06 on Steel Forgings and Billets.
ing and retesting methods and procedures, marking,
Current edition approved Sept. 1, 2022. Published September 2022. Originally
certification,productanalysisvariations,andadditionalsupple-
approved in 1976. Last previous edition approved in 2017 as A729/A729M – 17.
DOI: 10.1520/A0729_A0729M-17R22. mentary requirements.
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For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
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Standards volume information, refer to the standard’s Document Summary page on Available from Association of American Railroads (AAR), 425 3rd St., SW,
the ASTM website. Washington, DC 20024, http://www.aar.org.
*A Summary of Changes section appears at the end of this standard
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