ASTM A471-05
(Specification)Standard Specification for Vacuum-Treated Alloy Steel Forgings for Turbine Rotor Disks and Wheels
Standard Specification for Vacuum-Treated Alloy Steel Forgings for Turbine Rotor Disks and Wheels
SCOPE
1.1 This specification covers vacuum-treated alloy steel forgings intended for use as turbine rotor disks and wheels.
1.2 The values stated in inch-pound units are to be regarded as the standard.
1.3 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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Standards Content (Sample)
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Designation: A 471 – 05
Standard Specification for
Vacuum-Treated Alloy Steel Forgings for Turbine Rotor
1
Disks and Wheels
This standard is issued under the fixed designation A 471; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope* 3.3 Supplementary requirements are provided and shall
apply only when specified in the purchaser’s order.
1.1 This specification covers vacuum-treated alloy steel
forgings intended for use as turbine rotor disks and wheels.
4. Materials and Manufacture
1.2 The values stated in inch-pound units are to be regarded
4.1 Melting Process:
as the standard.
4.1.1 The steel shall be made by the basic electric-furnace
1.3 This standard does not purport to address all of the
process.
safety concerns, if any, associated with its use. It is the
4.1.2 Provisions for subsequent secondary melting of the
responsibility of the user of this standard to establish appro-
steel by the consumable electrode-electroslag or vacuum-arc
priate safety and health practices and determine the applica-
remelting processes are included in Supplementary Require-
bility of regulatory limitations prior to use.
ment S4.
2. Referenced Documents 4.2 Vacuum Treatment—The vacuum degassing require-
2 ments of Specification A 788 are mandatory.
2.1 ASTM Standards:
4.2.1 The molten steel shall be vacuum treated prior to or
A 275/A 275M Test Method for Magnetic Particle Exami-
during the pouring of the ingot in order to remove objection-
nation of Steel Forgings
able gases, particularly hydrogen.
A 370 Test Methods and Definitions for MechanicalTesting
4
4.2.1.1 When the vacuum stream degassing process is
of Steel Products
used,thevacuumsystemmustbeofsufficientcapacitytoeffect
A 388/A 388M Practice for Ultrasonic Examination of
a blank-off pressure low enough (usually less than 1000 µm) to
Heavy Steel Forgings
break up the normal tight, rope-like stream of molten metal
A 788 Specification for Steel Forgings, General Require-
into a wide-angled conical stream of relatively small droplets.
ments
The capacity of the system must also be sufficiently high to
E30 Test Methods for Chemical Analysis of Steel, Cast
3
reduce the initial surge pressure at the start of the pour to a low
Iron, Open-Hearth Iron, and Wrought Iron
level within 2 min.
E 139 Practice for Conducting Creep, Creep-Rupture, and
4
4.2.1.2 When the vacuum-lift process is utilized, the mol-
Stress-Rupture Tests of Metallic Materials
tenmetalshallberepeatedlydrawnintotheevacuatedvesselto
3. Ordering Information
give a recirculation factor (Note 1) of at least 2.5 to ensure
thorough degassing and mixing of the entire heat. The evacu-
3.1 The purchaser shall specify in the inquiry and order the
ation system shall be capable of reducing the pressure surges,
class of steel desired and test and purchase options (see 4.5.5,
which occur each time a new portion of steel is admitted to the
5.2.2, 6.1, 6.3, 7, and 15.1).
vessel, to increasingly lower levels until a blank-off pressure
3.2 Forging Drawing—Each forging shall be manufactured
(usually less than 1000 µm) is achieved.
in accordance with a purchaser-supplied drawing showing the
finished dimensions and the locations of mechanical test
NOTE 1—The recirculation factor is obtained as follows:
specimens.
tons of steel lifted per cycle 3 number of cycles
heat weight in tons
1
This specification is under the jurisdiction of ASTM Committee A01 on Steel,
4.2.1.3 When the ladle degassing process is used, the
Stainless Steel, and RelatedAlloys, and is the direct responsibility of Subcommittee
evacuation system shall be capable of reducing the system
A01.06 on Steel Forgings and Billets.
vacuum pressure to a low level (usually less than 1000 µm).
Current edition approved Sept. 1, 2005. Published September 2005. Originally
approved in 1962. Last previous edition approved in 2002 as A 471 – 02.
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
4
Standards volume information, refer to the standard’s Document Summary page on Details of the vacuum stream degassing process may be found in the Journal
the ASTM website. of the Iron and Steel Institute, Vol 191, January 1959; “Vacuum Pouring of Ingots
3
Withdrawn. for Heavy Forgings” by J. H. Stoll.
*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.
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A 471–05
The molten metal shall be adequate
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