ASTM A 729 Class A Structural and constructional steels

Material group: Ferrous Alloys / Structural and constructional steels

Country / Standard: United States / ASTM

Data updates

Latest Update: 2015-11

Total number of updates: 1

Update History

This material has 39 properties — only a subset is shown here.

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ASTM A 729 Class A Chemical Composition

CRITERIA

VALUE

UNIT

CAS NUMBER

CRITERIA

VALUE

≤ 0.04

UNIT

CAS NUMBER

7429-90-5

CRITERIA

VALUE

0.43 – 0.48

UNIT

CAS NUMBER

7440-44-0

CRITERIA

VALUE

0.20 – 0.35

UNIT

CAS NUMBER

7440-47-3

CRITERIA

VALUE

val1

UNIT

CAS NUMBER

7439-96-5

CRITERIA

VALUE

val1

UNIT

CAS NUMBER

7723-14-0

CRITERIA

VALUE

val1

UNIT

CAS NUMBER

7704-34-9

CRITERIA

VALUE

val1

UNIT

CAS NUMBER

7440-21-3

CRITERIA

VALUE

val1

UNIT

CAS NUMBER

7440-62-2

A729/A729M: 2017 / Standard Specification for Carbon and Alloy Steel Axles, Heat-Treated, for Mass Transit and Electric Railway Service

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ASTM A 729 Class A Physical Properties

Temperature

0 - 30°C

PROPERTY / VALUE

Modulus of Elasticity

190 — 210 GPa

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Density

7.67 — 7.86 kg/dm³

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Poisson Coefficient

0.27 — 0.3

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This material has 39 properties — only a subset is shown here.

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ASTM A 729 Class A Heat Treatments

After heating to and holding at an appropriate temperature in the austenitic range the axles shall be cooled in still air to under 260°C (500°F). They shall then be reheated into the austenitic range to the same or a lower temperature and again air cooled to under 260°C (500°F). A furnace charge thus treated is termed a double normalizing charge. After cooling, the axles are then tempered.
Tempering - Axles shall be reheated gradually to and held at an appropriate subcritical temperature and shall then be allowed to cool under uniform conditions. A furnace charge thus treated is termed a tempering charge. When required by supplementary requirement S2, axles that have been rough machined after heat treatment shall be heated to and held for an appropriate time at a temperature that is less than the last tempering temperature by at least 10°C (50°F). Then the axles shall be quenched directly into water with the axle length vertical.
Straightening- if necessary, shall be done before machining and at a temperature between 510°C (950°F)and 55°C (100°F) below the final tempering temperature. Straightening performed at temperatures lower than 510°C (950°F) shall be followed by stress relieving or applicable heat treatment. These requirements do not apply to straightening performed prior to final heat treatment.

ASTM A 729 Class A Mechanical Properties

Temperature

0 - 30°C

PROPERTY / VALUE

Tensile Strength

≥ 595 MPa

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Elongation, A

≥ 21 %

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Reduction of Area

val1 %

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Yield Strength, Rp0.2

≥ 330 MPa

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-Cross References

8Composition
8Mechanical Properties
3Physical Properties
1Heat Treatment
-Metallography
-Machinability

-Stress-Strain
-Formability
-Fatigue
-Fracture
-Creep

-Joints
-Coatings
19Dimensions
-Tribology

-Corrosion
-Ageing
-Weatherability
-Irradiation

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