ASTM A469/A469M-07(2012)
(Specification)Standard Specification for Vacuum-Treated Steel Forgings for Generator Rotors
Standard Specification for Vacuum-Treated Steel Forgings for Generator Rotors
ABSTRACT
This specification covers vacuum-treated basic electric steel forgings for use in generator rotors. Steel materials shall be manufactured by vacuum degassing, heat treatment, rough machining, and boring. Heat and product analyses shall be carried out to examine conformation of the specimens with chemical compositions of carbon, manganese, phosphorus, sulfur, silicon, nickel, chromium, molybdenum, vanadium, and antimony. Forgings shall also go through tension, impact, and Charpy V-notch tests, and shall conform with the following tensile and notch toughness requirements: tensile strength, yield strength, elongation, reduction of area, FATT50, and Charpy absorbed energy. Nondestructive test methods such as ultrasonic and internal inspection shall be performed.
SCOPE
1.1 This specification covers vacuum-treated basic electric steel forgings for generator rotors.
1.2 Supplementary requirements are provided, both in this standard and in Specification A788/A788M, for use when additional testing, inspection or processing is required by the purchaser.
1.3 The values stated in either inch-pound or SI (metric) units are to be regarded separately as standards. Within the text and tables, the SI units are shown in brackets. The values stated in each system are not exact equivalents; therefore, each system must be used independent of the other. Combining values from the two systems may result in nonconformance with the specification.
1.4 Unless the order specifies the applicable “M” specification designation, the material shall be furnished to the inch-pound units.
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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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:A469/A469M −07 (Reapproved 2012)
Standard Specification for
Vacuum-Treated Steel Forgings for Generator Rotors
This standard is issued under the fixed designationA469/A469M; 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. Ordering Information and General Requirements
1.1 This specification covers vacuum-treated basic electric 3.1 In addition to the ordering information required by
steel forgings for generator rotors.
Specification A788/A788M, the purchaser shall include with
the inquiry and order, a dimensioned drawing showing the
1.2 Supplementary requirements are provided, both in this
mechanical test specimen locations, together with:
standard and in Specification A788/A788M, for use when
3.1.1 Details of any required magnetic permeability tests
additional testing, inspection or processing is required by the
(6.1).
purchaser.
3.1.2 If the yield strength is to be determined at an offset of
1.3 The values stated in either inch-pound or SI (metric)
0.2%(Table 1), and number of tests (7.1.2 and 7.1.3).
units are to be regarded separately as standards.Within the text
3.1.3 If vertical heat treatment is required (S3).
andtables,theSIunitsareshowninbrackets.Thevaluesstated
3.1.4 If heat treatment by normalizing and tempering is
in each system are not exact equivalents; therefore, each
required (4.2.2 and 4.2.3).
system must be used independent of the other. Combining
3.1.5 If post rough machining stress relief may be omitted
values from the two systems may result in nonconformance
for forgings that have been double tempered (4.2.2).
with the specification.
3.1.6 Details for boring including dimensions, finish, timing
1.4 Unless the order specifies the applicable “M” specifica-
and additional testing if required (8.3 and S1).
tion designation, the material shall be furnished to the inch-
3.1.7 Any applicable instructions regarding the required
pound units.
nondestructive examinations (8).
2. Referenced Documents
3.1.8 If vacuum arc remelted ingots are to be used, the
purchaser may require that footnoteA to Table 2 be applicable.
2.1 ASTM Standards:
A275/A275M Practice for Magnetic Particle Examination of
3.2 Material supplied to this specification shall conform to
Steel Forgings
the requirements of Specification A788/A788M, which out-
A341/A341M Test Method for Direct Current Magnetic
lines additional ordering information, manufacturing
Properties of Materials Using D-C Permeameters and the
requirements, testing and retesting methods and procedures,
Ballistic Test Methods
marking, certification, production analysis variations, and ad-
A370 Test Methods and Definitions for Mechanical Testing
ditional supplementary requirements.
of Steel Products
3.3 Failure to comply with the applicable general require-
A418/A418M Practice for Ultrasonic Examination of Tur-
ments of Specification A788/A788M constitutes nonconfor-
bine and Generator Steel Rotor Forgings
mance with this specification.
A773/A773M Test Method for dc Magnetic Properties of
Materials Using Ring and Permeameter Procedures with 3.4 If the requirements of this specification are in conflict
dc Electronic Hysteresigraphs
with the requirements of Specification A788/A788M, the
A788/A788M Specification for Steel Forgings, General Re- requirements of this specification shall prevail.
quirements
4. Materials and Manufacture
This specification is under the jurisdiction of ASTM Committee A01 on Steel,
4.1 The vacuum degassing requirements of Specification
Stainless Steel and Related Alloys and is the direct responsibility of Subcommittee
A01.06 on Steel Forgings and Billets. A788/A788M are mandatory.
Current edition approved May 1, 2012. Published May 2012. Originally
4.1.1 Other vacuum methods of degassing may be used if
approved in 1962. Last previous edition approved in 2007 as A469/A469M – 07.
the supplier can demonstrate their adequacy to the satisfaction
DOI: 10.1520/A0469_A0469M-07R12.
of the purchaser, but in this case, hydrogen testing per
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
Supplementary Requirement S4 is mandatory.
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. 4.2 Heat Treatment:
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
A469/A469M−07 (2012)
TABLE 1 Tensile and Notch Toughness Requirements
Grade
Tensile strength, min, ksi 80 90 100 110 100 110 120
[MPa] [550] [620] [690] [760] [690] [760] [825]
A
Yield strength, min, ksi 55 70 80 90 80 90 100
[MPa] [380] [485] [550] [620] [550] [620] [690]
Elongation in 2 in. or 50 mm, min, % 20 20 17 15 18 17 16
Reduction of area, min, % 50 50 45 40 55 50 45
FATT , max, F 100 100 120 175 0 20 40
[FATT , max, C] [38] [38] [49] [80] [−18] [−7] [4]
Charpy absorbed energy at 70 ± 5 30 30 25 15 60 50 40
°F [20 ± 3 °C],
min, ft·lbf[J] [40] [40] [34] [20] [80] [68] [55]
A
Yield strength at 0.02 % offset. Yield strength may also be specified at 0.2 % offset in which case 5000 psi (35 MPa) shall be added to these values.
TABLE 2 Chemical Requirements
Element Composition, %
Grade 2 Grade 3 Grade 4 Grade 5 Grades 6, 7, 8
Carbon, max 0.25 0.27 0.27 0.31 0.28
Manganese, max 0.60 0.60 0.70 0.70 0.60
Phosphorus, max 0.015 0.015 0.015 0.015 0.015
Sulfur, max 0.015 0.015 0.015 0.015 0.015
A
Silicon, max 0.30 0.30 0.30 0.30 0.30
Nickel 2.50 min 2.50 min 3.00 min 3.00 min 3.25 to 4.00
Chromium 0.50 max 0.50 max 0.50 max 0.50 max 1.25 to 2.00
Molybdenum 0.20 to 0.50 0.20 to 0.50 0.20 to 0.60 0.20 to 0.70 0.30 to 0.60
Vanadium 0.03 min 0.03 min 0.03 min 0.05 to 0.15 0.05 to 0.15
B
Antimony . . . . .
A
Optional: For steel that is to be vacuum arc remelted a minimum silicon of 0.15 % may be specified.
B
Report for information on Grades 6, 7, and 8.
4.2.1 Vertical heat treatment of the rotor forging is 5.2 ProductAnalysis—The manufacturer shall use the prod-
preferred, and Supplementary Requirement S3 should be uct analysis provision of Specification A788/A788M to obtain
specified by the purchase order if this is required. a product analysis from a forging representing each heat or
multiple heat.
4.2.2 The heat treatment for mechanical properties shall
consist of quenching and tempering, but normalizing and
tempering is permissible with prior purchaser approval. Also, 6. Magnetic Properties
with prior purchaser approval, the post rough machining stress
6.1 When specified in the ordering information, a perme-
relief in 4.2.3 may be omitted when double tempering is used,
ability test shall be performed in accordance with the latest
instead of a single temper, to complete this heat treatment
issue of Test Method A341/A341M or Test Method A773/
cycle.
A773M.
4.2.3 After heat treatment and the subsequent rough
machining, the forging shall be stress relie
...
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