ASTM A940/A940M-06(2016)
(Specification)Standard Specification for Vacuum Treated Steel Forgings, Alloy, Differentially Heat Treated, for Turbine Rotors (Withdrawn 2017)
Standard Specification for Vacuum Treated Steel Forgings, Alloy, Differentially Heat Treated, for Turbine Rotors (Withdrawn 2017)
ABSTRACT
This specification covers vacuum treated and differentially heat treated alloy steel forgings for turbine rotors. Materials shall be manufactured by melting process, heat treatment (consisting of normalizing and tempering to achieve creep resistance in the high pressure portion, and quenching and tempering to achieve high toughness in the low pressure portion), rough machining, and boring. Heat and product analyses shall be performed to evaluate conformance of the steel to required chemical compositions. Tension and impact tests shall also be executed to make sure that forgings adhere to tensile and notch toughness requirements, including tensile strength, yield strength, elongation, and reduction of area. Final products shall be free of cracks, seams, laps, shrinkage, and other injurious imperfections. To evaluate such imperfections, nondestructive tests, such as ultrasonic and internal inspection procedures, may be conducted at the preference of the purchaser. Forgings that do not meet the requirements specified, may be retreated one or more times, but not more than three additional times.
SCOPE
1.1 This specification covers vacuum treated, alloy steel forgings, differentially heat treated for turbine rotors.
1.2 Differential heat treatment of a rotor forging involves subjecting two portions of the forging concurrently to two different austenitizing temperatures followed by two different cooling rates for normalizing and quenching, and then tempering, to achieve creep resistance in the high pressure (HP) portion and high toughness in the low pressure (LP) portion.2
1.3 The values stated in either SI units or inch-pound units are to be regarded separately as standard. 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 non-conformance with the standard.
WITHDRAWN RATIONALE
This specification covers vacuum treated, alloy steel forgings, differentially heat treated for turbine rotors.
Formerly under the jurisdiction of Committee A01 on Steel, Stainless Steel and Related Alloys, this specification was withdrawn in November 2017. This standard is being withdrawn without replacement due to its limited use by industry.
General Information
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Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation:A940/A940M −06 (Reapproved 2016)
Standard Specification for
Vacuum Treated Steel Forgings, Alloy, Differentially Heat
1
Treated, for Turbine Rotors
This standard is issued under the fixed designationA940/A940M; 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 E139 Test Methods for Conducting Creep, Creep-Rupture,
and Stress-Rupture Tests of Metallic Materials
1.1 This specification covers vacuum treated, alloy steel
forgings, differentially heat treated for turbine rotors.
3. Ordering Information
1.2 Differential heat treatment of a rotor forging involves
3.1 In addition to the ordering information required by
subjecting two portions of the forging concurrently to two
Specification A788/A788M, the purchaser shall include with
different austenitizing temperatures followed by two different
the inquiry and order a detailed drawing, sketch, or written
cooling rates for normalizing and quenching, and then
description of the forging, including the mechanical test
tempering, to achieve creep resistance in the high pressure
locations, the portion of the forging to be included in the
(HP) portion and high toughness in the low pressure (LP)
2
heating chamber during the stability test, and the minimum
portion.
stability test temperature.
1.3 The values stated in either SI units or inch-pound units
3.2 The purchaser shall specify if check tests for mechanical
are to be regarded separately as standard. The values stated in
properties are required after stress relief or heat stability tests.
each system may not be exact equivalents; therefore, each
system shall be used independently of the other. Combining
3.3 Supplementary Requirements—Supplementary require-
values from the two systems may result in non-conformance
ments are provided. These requirements shall apply only when
with the standard.
specified in the purchase order.
2. Referenced Documents
4. General Requirements
3
2.1 ASTM Standards:
4.1 Material supplied to this specification shall conform to
A275/A275M Practice for Magnetic Particle Examination of
the requirements of Specification A788/A788M, which out-
Steel Forgings
lines additional ordering information, manufacturing
A370 Test Methods and Definitions for Mechanical Testing
requirements, testing and retesting methods and procedures,
of Steel Products
marking, certification, product analysis variations, and addi-
A418/A418M Practice for Ultrasonic Examination of Tur-
tional supplementary requirements.
bine and Generator Steel Rotor Forgings
A470/A470M Specification for Vacuum-Treated Carbon and
4.2 If the requirements of this specification are in conflict
Alloy Steel Forgings for Turbine Rotors and Shafts
with the requirements of Specification A788/A788M, the
A472/A472M Specification for Heat Stability of Steam Tur-
requirements of this specification shall prevail.
bine Shafts and Rotor Forgings
A788/A788M Specification for Steel Forgings, General Re-
5. Manufacture
quirements
5.1 Melting processes of Specification A788/A788M shall
be applicable, except that the open hearth or basic oxygen
1
This specification is under the jurisdiction of ASTM Committee A01 on Steel,
methods of primary melting shall not be used and the molten
Stainless Steel and Related Alloys and is the direct responsibility of Subcommittee
A01.06 on Steel Forgings and Billets. steel shall be vacuum treated during processing. Except for
Current edition approved March 1, 2016. Published April 2016. Originally
vacuum stream degassed ingots, the hydrogen content shall be
approved in 1995. Last previous edition approved in 2011 as A940/A940M – 06
determined. The acceptable hydrogen limit as well as the stage
(2011). DOI: 10.1520/A0940_A0940M-06R16.
2 in processing when sampling, the sample preparation proce-
Symposium on Steel Forgings, ASTM STP 903, ASTM International, West
Conshohocken, PA, 1984, pp. 59–86.
dure and the method of analysis shall be established between
3
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
the manufacturer and the purchaser.
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
5.1.1 If the ESR process is used, the electrodes shall have
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. been produced from vacuum treated primary heat(s).
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A940/A940M−06 (2016)
5.2 In addition to the requirements of Specification A788/ testsampletakenpreferablyd
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