ASTM A472/A472M-07(2012)
(Specification)Standard Specification for Heat Stability of Steam Turbine Shafts and Rotor Forgings
Standard Specification for Heat Stability of Steam Turbine Shafts and Rotor Forgings
ABSTRACT
This measurement method covers the procedures for the standard practice of determining the heat stability of steam turbine and rotor forgings to ensure stability at operating temperature. Surface and test band preparation, and heating and cooling procedures prior to stability measurements are detailed. Interpretation of the results of cold and hot measurements is also described.
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 unit 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 may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in nonconformance with the standard.
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 and health practices and determine the applicability of regulatory limitations prior to use.
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Designation: A472/A472M −07 (Reapproved 2012)
Standard Specification for
Heat Stability of Steam Turbine Shafts and Rotor Forgings
This standard is issued under the fixed designationA472/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 3. Procedure
1.1 This specification covers the determination of heat 3.1 The heat stability test shall be conducted by the forging
stability of steam turbine shafts and rotor forgings to ensure supplier after final heat treatment and after the forging has been
centered and machined with allowance to finish to the purchas-
stability at operating temperature. This specification is not
ordinarily applicable to generator rotor forgings. er’s drawing. Material for mechanical tests may be removed
before or after the stability test at the manufacturer’s option,
1.2 This specification is expressed in both inch-pound unit
unless check tests after the stability test are required by the
and in SI units; however, unless the purchase order or contract
purchaser.
specifies the applicable M specification designation (SI units),
3.2 With prior approval from the purchaser, the forgings
the inch-pound units shall apply. The values stated in either
may be stress-relieved as part of the heat stability test. When
inch-pound units or SI units are to be regarded separately as
this is done, the stress-relieving temperature shall be within 50
standard. Within the specification, the SI units are shown in
to 100°F [30 to 55°C] below final tempering temperature.
brackets. The values stated in each system may not be exact
Rotate the forgings at 2 to 4 r/min and hold at stress-relieving
equivalents;therefore,eachsystemshallbeusedindependently
temperature for at least 2 h/in. [2 h/25 mm] of maximum radial
of the other. Combining values from the two systems may
result in nonconformance with the standard. thickness, after which the temperature may be decreased to the
specified heat stability test temperature and the test performed.
1.3 Supplementary requirements of an optional nature are
provided for use at the option of the purchaser. The supple-
4. Heat Stability Test Bands
mentary requirements shall apply only when specified indi-
4.1 The supplier shall mark positionsA, B, C, and D, spaced
vidually by the purchaser in the purchase order or contract.
90°apartcircumferentially,preferablyonanendoftheforging.
1.4 This standard does not purport to address all of the
Markings shall be retained throughout all subsequent opera-
safety concerns, if any, associated with its use. It is the
tions.
responsibility of the user of this standard to establish appro-
4.2 Preferably, there shall be a minimum of 5 test bands,
priate safety and health practices and determine the applica-
denoted as 1, 2, 3, 4, and 5, machined on the circumference of
bility of regulatory limitations prior to use.
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
2. Ordering Information
the forging as practical. Band 3 shall be located as near to
2.1 It shall be the responsibility of the purchaser to specify
midlength as practical. Bands 2 and 4 shall be located
all requirements necessary for testing under this specification.
approximately equidistant between 1 and 3, and 3 and 5,
Requirements to be considered include, but are not limited to,
respectively.
the following:
4.3 When the shipped length of the barrel portion of the
2.1.1 ASTM designation and year date,
forging is less than 8 ft [2.4 m], bands 2 and 4 may be omitted.
2.1.2 The minimum test temperature,
2.1.3 The portion of the forging to be subjected to the heat 4.4 The purchaser’s drawing may show the desired number
stability test temperature, and and location of bands and shall indicate that portion of the
2.1.4 Supplementary or other special requirements. 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.
This specification is under the jurisdiction of ASTM Committee A01 on Steel,
Stainless Steel and Related Alloys and is the direct responsibility of Subcommittee
4.5 The test bands shall be machined with the forging
A01.06 on Steel Forgings and Billets.
running on centers except in the cases of forgings weighing
Current edition approved May 1, 2012. Published May 2012. Originally
over 125 000 lb [56.7 metric tons] the machining shall be
approved in 1962. Last previous edition approved in 2007 as A472/A472M – 07.
DOI: 10.1520/A0472_A0472M-07R12. performed with the forgings running on steady rests. Readings
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
A472/A472M − 07 (2012)
shall be taken with the forging running on centers except in the 1 h. If runout continues to exceed 0.002 in. [0.05 mm], recenter
cases of forgings weighing over 125 000 lb [56.7 metric tons] the forging or remachine the bands until the runout does not
where readings may be taken with the forgings running on exceed 0.002 in. [0.05 mm] in any band. Refer to the last
steady rests. Between readings, the forgings may be rotated on measurements as the official first cold measurements.
steady rests.
7.3 Hot Measurements—Take measurements on all bands
hourly during the heating cycle until the forging has been
5. Surface Preparation
heated to the specified temperature. When three consecutive
5.1 Removeoil,grease,dirt,andotherforeignmaterialfrom
hourly deflection measurements at the specified temperature
the surface of the forging prior to the heat stability test. A
check within 0.0005 in. [0.013 mm], cooling may commence.
suitable coating may be applied to provide uniform emissivity.
Refer to the last of these measurements as the official hot
measurements.
6. Heating and Cooling
7.4 Second Cold Measurements—After cooling in accor-
6.1 Place the f
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