ASTM A472/A472M-23

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 to the previous version. Because
it 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 version
of the standard as published by ASTM is to be considered the official document.
Designation: A472/A472M − 07 (Reapproved 2022) A472/A472M − 23
Standard Specification for
Heat Stability of Steam Turbine Shafts and Rotor Forgings
This standard is issued under the fixed designation A472/A472M; 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 Scope*
1.1 This specification covers the determination of heat stability of steam turbine shafts and rotor forgings to ensure stability at
operating temperature. This specification is not ordinarily applicable to generator rotor forgings.
1.2 This specification is expressed in both inch-pound units and in SI units; however, unless the purchase order or contract
specifies the applicable M specification designation (SI units), the inch-pound units shall apply. The values stated in either
inch-pound units or SI units are to be regarded separately as standard. Within the specification, the SI units are shown in brackets.
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.
1.3 Supplementary requirements of an optional nature are provided for use at the option of the purchaser. The supplementary
requirements shall apply only when specified individually by the purchaser in the purchase order or contract.
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of
regulatory limitations prior to use.
1.5 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.
2. Referenced Documents
2.1 ASTM Standards:
A788 Specification for Steel Forgings, General Requirements
A941 Terminology Relating to Steel, Stainless Steel, Related Alloys, and Ferroalloys
3. Terminology
3.1 Definitions:
3.1.1 For definitions of terms specific to this standard, refer to Specification A788 and Terminology A941.
This specification is under the jurisdiction of ASTM Committee A01 on Steel, Stainless Steel and Related Alloys and is the direct responsibility of Subcommittee A01.06
on Steel Forgings and Billets.
Current edition approved March 1, 2022Nov. 1, 2023. Published March 2022November 2023. Originally approved in 1962. Last previous edition approved in 20172022
as A472/A472M – 07 (2022).(2017). DOI: 10.1520/A0472_A0472M-07R22.10.1520/A0472_A0472M-23.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
A472/A472M − 23
4. Ordering Information
4.1 It shall be the responsibility of the purchaser to specify all requirements necessary for testing under this specification.
Requirements to be considered include, but are not limited to, the following:
4.1.1 ASTM designation and year date,
4.1.2 The minimum test temperature,
4.1.3 The portion of the forging to be subjected to the heat stability test temperature, and
4.1.4 Supplementary or other special requirements.
5. Procedure
5.1 The heat stability test shall be conducted by the forging supplier after final heat treatment and after the forging has been
centered and machined with allowance to finish to the purchaser’s drawing. Material for mechanical tests may be removed before
or after the stability test at the manufacturer’s option, unless check tests after the stability test are required by the purchaser.
5.2 With prior approval from the purchaser, the forgings may be stress-relieved as part of the heat stability test. When this is done,
the stress-relieving temperature shall be within 50 °F to 100 °F [30 °C to 55 °C] below final tempering temperature. Rotate the
forgings at 2 r ⁄min to 4 r/min and hold at stress-relieving temperature for at least 2 h/in. [2 h/25 mm] of maximum radial thickness,
after which the temperature may be decreased to the specified heat stability test temperature and the test performed.
6. Heat Stability Test Bands
6.1 The supplier shall mark positions A, B, C, and D, spaced 90° apart circumferentially, preferably on an end of the forging.
Markings shall be retained throughout all subsequent operations.
6.2 Preferably, there shall be a minimum of 5 test bands, denoted as 1, 2, 3, 4, and 5, machined on the circumference of the forging.
Numbering shall start at the left side of the forging drawing. Bands 1 and 5 shall be located as close to the end of the forging as
practical. Band 3 shall be located as near to midlength as practical. Bands 2 and 4 shall be located approximately equidistant
between 1 and 3, and 3 and 5, respectively.
6.3 When the shipped length of the barrel portion of the forging is less than 8 ft [2.4 m], bands 2 and 4 may be omitted.
6.4 The purchaser’s drawing may show the desired number and location of bands and shall indicate that portion of the forging that
shall be located within the heating chamber. Bands 1 and 5 are to be located outside of the heating chamber. Preferably, the gland
areas/packing seal areas are inside the heating chamber.
6.5 The test bands shall be machined with the forging running on centers except in the cases of forgings weighing over 125 000
lb [56.7 metric tons] the machining shall be performed with the forgings running on steady rests. Readings shall be taken with the
forging running on centers except in the cases of forgings weighing over 125 000 lb [56.7 metric tons] where readings may be taken
with the forgings running on steady rests. Between readings, the forgings may be rotated on steady rests.
7. Surface Preparation
7.1 Remove oil, grease, dirt, and other foreign material from the surface of the forging prior to the heat stability test. A suitable
coating may be applied to provide uniform emissivity.
8. Heating and Cooling
8.1 Place the forging in the heating chamber and rotate the forging at a speed of 2 r ⁄min to 4 r/min.
8.2 Place thermocouples in contact with the forging at each test band within the heating chamber. Shield the thermoco
...