ASTM A472 - A 472M - 23

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Designation: A472/A472M −23
Standard Speciﬁcation for
Heat Stability of Steam Turbine Shafts and Rotor Forgings
1
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*
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 supple-
mentary requirements shall apply only when speciﬁed indi-
vidually 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 appro-
priate safety, health, and environmental practices and deter-
mine the applicability of regulatory limitations prior to use.
1.5 This international standard was developed in accor-
dance with internationally recognized principles on standard-
ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom-
mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
2
A788 Speciﬁcation for Steel Forgings, General Require-
ments
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.
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 purchas-
er’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 opera-
tions.
1
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 Nov. 1, 2023. Published November 2023. Originally
approved in 1962. Last previous edition approved in 2022 as A472/A472M – 07
(2022). DOI: 10.1520/A0472_A0472M-23.
2
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
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.
1

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 thermocouples

from the heat source.

8.3 Apply heat uniformly to avoid localized overheating.

Heat the forging at a rate not exceeding 200 °F ⁄h [110 °C ⁄h] to

the stability test temperature speciﬁed by the purchaser. Main-

tain the speciﬁed testing temperature until the forging is heated

uniformly. A uniform temperature condition shall be consid-

ered to exist when three consecutive hourly deﬂection mea-

surements taken at the test temperature are within 0.0005 in.

[0.013 mm]. To consider a uniform test temperature condition

to exist, it is also necessary that the axial thermal expansion be

consistent within 0.010 in. [0.25 mm] for three consecutive

hourly readings at the test temperature.

8.4 After uniform test conditions as described in 8.3 have

been reached, cool the forging, while rotating, to below 100 °F

[40 °C]. The heating chamber may be opened during cooling,

but the cover shall not be removed until the temperature of the

forging is less than 500 °F [260 °C]. After the forging has

cooled to approximately room temperature, rotate it for at least

2 h before the second cold measurements (see 9.4) are re-

corded.

9. Stability Measurements

9.1 Use an indicator located outside the heating chamber to

measure to the nearest 0.0005 in. [0.013 mm]. Actuate the

indicator by a rod with one end contacting the forging at test

bands described in 6.2 or 6.3. Take measurements at each test

band at positions A, B, C, and D. For each band, the indicator

may be set to zero for the minimum deﬂection at one of the

positions A, B, C, or D or the ﬁgures may be reduced to

minima by subtraction.

9.2 First Cold Measurements—Take measurements on each

band after rotation is started but prior to heating. If the runout

exceeds 0.002 in. [0.05 mm] at any band, continue rotation for

1 h. If runout continues to exceed 0.002 in. [0.05 mm], recenter

the forging or remachine the bands until the runout does not

exceed 0.002 in. [0.05 mm] in any band. Refer to the last

measurements as the official ﬁrst cold measurements.

9.3 Hot Measurements—Take measurements on all bands

hourly during the heating cycle until the forging has been

heated to the speciﬁed temperature. When three consecutive

hourly deﬂection measurements at the speciﬁed temperature

check within 0.0005 in. [0.013 mm], cooling may commence.

Refer to the last of these measurements as the official hot

measurements.

9.4 Second Cold Measurements—After cooling in accor-

dance with 8.4, take measurements on all bands at half-hour

intervals until two consecutive deﬂection measurements check

within 0.0005 in. [0.013 mm]. Refer to the last of these

measurements as the official second cold measurements.

10. Interpretation of Results

10.1 The forging shall be acceptable if the movement of its

center is not greater than 0.001 in. [0.025 mm] when deter-

mined by the difference between the official hot and the official

cold second measurements. This movement shall be deter-

mined for each band as follows:

10.1.1 From the official hot measurements at position A

subtract the official cold measurement for position A.

10.1.2 Repeat the procedure for positions B, C, and D.

10.1.3 For each of these four results, numerically total the

greatest plus value and the greatest minus value without regard

to sign. The maximum deﬂection in any band as indicated by

these totals shall not exceed 0.002 in. [0.05 mm].

10.2 In case of changes in measurements in bands 1 and 5,

suitable corrections may be made to results obtained from

bands 2, 3, and 4. The corrected ﬁgures shall be within the

requirements of 10.1.3.

10.3 If the forging does not meet the requirements of the

stability test, it may be retested, stress relieved before retest, or

completely reheat treated before retest.

11. Report

11.1 The forging supplier shall report to the purchaser the

official ﬁrst cold measurements, the hourly measurements

during heating and holding at speciﬁed temperature, the official

hot measurements and the official second cold measurements,

A472/A472M − 23

as well as the temperature of the forging when these measure-

ments were obtained. The report shall include the calculated

change in measurements as determined under 10.1.3.

12. Keywords

12.1 emissivity; heat stability; rotor forgings; steam turbines

SUPPLEMENTARY REQUIREMENTS

The following supplementary requirements shall only apply when speciﬁed individually by the

purchaser in the contract or purchase order.

S1. Emissivity Coating

S1.1 Apply a surface coating that will provide a uniform

thermal emissivity throughout the test. The coating shall be

uniform and completely cover all surfaces within and adjacent

to the ovens. Successive light coats applied by spraying are

recommended.

APPENDIX

(Nonmandatory Information)

X1. RESULTS DISCUSSION

X1.1 This speciﬁcation determines whether a forging will

be stable at elevated temperatures and sets go/no go limits for

acceptance. Instability is typically caused by one of several

factors including non-uniform emissivity (see Supplementary

Requirement S1) or relief of residual stresses (in both cases

these rotors will normally be stable during a subsequent test),

non-uniform heat treatment, and machining off the forging

centerline. Rotors that do not meet the go/no go limits are

considered unstable and are normally subject to further review,

retested, or even re-heat treated and retested.

SUMMARY OF CHANGES

Committee A01 has identiﬁed the location of selected changes to this standard since the last issue

(A472/A472M – 07 (2022)) that may impact the use of this standard. (Approved Nov. 1, 2023.)

(1) Added Referenced Documents Section 2and Terminology

Section 3.

ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentioned

in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk

of 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 and

if not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards

and should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of the

responsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you should

make 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, PA 19428-2959,

United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the above

address or at 610-832-9585 (phone), 610-832-9555 (fax), or service@astm.org (e-mail); or through the ASTM website

(www.astm.org). Permission rights to photocopy the standard may also be secured from the Copyright Clearance Center, 222

Rosewood Drive, Danvers, MA 01923, Tel: (978) 646-2600; http://www.copyright.com/

A472/A472M − 23

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摘要：

ASTM A472 - A 472M - 23 是行业标准中针对锅炉与过热器用铁素体合金钢无缝钢管的最新规范，涵盖材料的化学成分、力学性能、尺寸公差与检测要求。该标准适用于高温高压环境下使用的钢管，确保其在承受极端温度与压力时具备良好的抗氧化性、蠕变强度与韧性。文档中明确了管材的制造工艺、热处理条件、水压与无损检测要求，以及验收与标记规则。遵循 ASTM A472/A472M-23 可帮助工程师、采购人员与质量管理人员选择符合国际安全与性能标准的锅炉用管材，减少设备失效风险，提升电站与工业锅炉的

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