ASTM A508/A508M-18(2023)
(Specification)Standard Specification for Quenched and Tempered Vacuum-Treated Carbon and Alloy Steel Forgings for Pressure Vessels
Standard Specification for Quenched and Tempered Vacuum-Treated Carbon and Alloy Steel Forgings for Pressure Vessels
ABSTRACT
This specification covers quenched and tempered vacuum-treated carbon and alloy steel forgings for pressure vessels, such as those used in reactor systems, specifically, vessel closures, shells, flanges, tube sheets, rings, heads, and similar parts. Steels shall be manufactured by basic electric-furnace process except when secondary ladle refining or remelting process is employed, and shall be vacuum treated prior to or during the pouring of the ingot. Materials shall also go through preliminary heat treatment and quenching for mechanical properties. Heat and product analyses shall be executed to evaluate the conformance of the forgings with specified chemical requirements. Tension and Charpy impact tests shall also be performed to examine the conformance of steel specimens with the following mechanical properties: tensile strength, yield strength, elongation, and reduction of area. Nondestructive inspection procedures, such as magnetic particle examination, and longitudinal wave and angle beam ultrasonic examination, shall also be carried out. Repair welding may be permitted at the option of the purchaser.
SCOPE
1.1 This specification2 covers quenched and tempered vacuum-treated carbon and alloy steel forgings for pressure vessels such as those used in reactor systems. Specifically, it covers forgings for vessel closures, shells, flanges, tube sheets, rings, heads, and similar parts.
1.2 All grades are considered weldable under proper conditions. Welding technique is of fundamental importance, and it is presupposed that welding procedure and inspection will be in accordance with approved methods for the grade of material used.
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.
1.4 Unless the order specifies the applicable “M” specification designation, the material shall be furnished to the inch-pound units.
Note 1: Grades 1 and 1A are composed of different chemistries but have the same mechanical requirements.
Note 2: Designations have been changed as follows:
Current
Formerly
Grade 1
Class 1
Grade 1A
Class 1A
Grade 2 Class 1
Class 2
Grade 2 Class 2
Class 2A
Grade 3 Class 1
Class 3
Grade 3 Class 2
Class 3A
Grade 4N Class 1
Class 4
Grade 4N Class 2
Class 4A
Grade 4N Class 3
Class 4B
Grade 5 Class 1
Class 5
Grade 5 Class 2
Class 5A
Grade 22 Class 3
Class 22B
Grade 22 Classes 4, 5, 6, and 7
Grade 3V
Class 3V
1.5 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
1.6 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.
General Information
Relations
Buy Standard
Standards Content (Sample)
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.
Designation: A508/A508M − 18 (Reapproved 2023)
Standard Specification for
Quenched and Tempered Vacuum-Treated Carbon and Alloy
Steel Forgings for Pressure Vessels
This standard is issued under the fixed designation A508/A508M; 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.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope
Grade 5 Class 2 Class 5A
Grade 22 Class 3 Class 22B
1.1 This specification covers quenched and tempered
Grade 22 Classes 4, 5, 6, and 7
vacuum-treated carbon and alloy steel forgings for pressure Grade 3V Class 3V
vessels such as those used in reactor systems. Specifically, it
1.5 This standard does not purport to address all of the
covers forgings for vessel closures, shells, flanges, tube sheets,
safety concerns, if any, associated with its use. It is the
rings, heads, and similar parts.
responsibility of the user of this standard to establish appro-
priate safety, health, and environmental practices and deter-
1.2 All grades are considered weldable under proper condi-
mine the applicability of regulatory limitations prior to use.
tions. Welding technique is of fundamental importance, and it
is presupposed that welding procedure and inspection will be in
1.6 This international standard was developed in accor-
accordance with approved methods for the grade of material
dance with internationally recognized principles on standard-
used. ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom-
1.3 The values stated in either SI units or inch-pound units
mendations issued by the World Trade Organization Technical
are to be regarded separately as standard. The values stated in
Barriers to Trade (TBT) Committee.
each system may not be exact equivalents; therefore, each
system shall be used independently of the other. Combining
2. Referenced Documents
values from the two systems may result in non-conformance
with the standard.
2.1 ASTM Standards:
A275/A275M Practice for Magnetic Particle Examination of
1.4 Unless the order specifies the applicable “M” specifica-
tion designation, the material shall be furnished to the inch- Steel Forgings
A370 Test Methods and Definitions for Mechanical Testing
pound units.
of Steel Products
NOTE 1—Grades 1 and 1A are composed of different chemistries but
A388/A388M Practice for Ultrasonic Examination of Steel
have the same mechanical requirements.
Forgings
NOTE 2—Designations have been changed as follows:
A788/A788M Specification for Steel Forgings, General Re-
Current Formerly
Grade 1 Class 1
quirements
Grade 1A Class 1A
A966/A966M Practice for Magnetic Particle Examination of
Grade 2 Class 1 Class 2
Steel Forgings Using Alternating Current
Grade 2 Class 2 Class 2A
Grade 3 Class 1 Class 3 E208 Test Method for Conducting Drop-Weight Test to
Grade 3 Class 2 Class 3A
Determine Nil-Ductility Transition Temperature of Fer-
Grade 4N Class 1 Class 4
ritic Steels
Grade 4N Class 2 Class 4A
Grade 4N Class 3 Class 4B E428 Practice for Fabrication and Control of Metal, Other
Grade 5 Class 1 Class 5
than Aluminum, Reference Blocks Used in Ultrasonic
Testing (Withdrawn 2019)
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. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved March 15, 2023. Published April 2023. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 1964. Last previous edition approved in 2018 as A508/A508M – 18. Standards volume information, refer to the standard’s Document Summary page on
DOI: 10.1520/A0508_A0508M-18R23. the ASTM website.
2 4
For ASME Boiler and Pressure Vessel Code applications see related Specifi- The last approved version of this historical standard is referenced on
cation SA-508/SA-508M in Section II of that Code. www.astm.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
A508/A508M − 18 (2023)
2.2 American Society of Mechanical Engineers Standard: 4.3.1 When specified by the purchaser, it is permissible to
Boiler and Pressure Vessel Code—Section III, Articles perform Magnetic particle examination using the AC yoke in
NB 2300, NC 2300, ND 2300, NE 2300, NF 2300, NG accordance with Practice A966/A966M instead of using Prac-
2300 tice A275/A275M (see 9.2.1).
4.4 The optional minimum silicon content as expressed in
3. Terminology
Footnote B to Table 1, if required.
3.1 Definitions:
4.5 If the requirements of this specification are in conflict
3.1.1 controlling cross section thickness (T )—the diameter
C
with the requirements of Specification A788/A788M, the
of the largest theoretical sphere which can be inscribed within
requirements of this specification shall prevail.
the volume of the forging.
5. Materials and Manufacture
4. Ordering Information
5.1 Melting Process:
4.1 Purchase Order—In addition to the ordering informa-
5.1.1 The steel shall be made by the basic electric-furnace
tion required by Specification A788/A788M, the purchaser
process except when secondary ladle refining or the remelting
shall include with the inquiry and order a detailed drawing that
process is employed, in which case the melting processes of
locates the areas of significant loading in the forging (when
Specification A788/A788M are permitted.
required), the method of selecting test locations (see 7.1.5 and
5.1.2 The molten steel shall be vacuum treated in accor-
7.1.6), and purchase options (see 5.2.2, 7.2, and 11.1) and any
dance with the methods described in Specification A788/
supplementary requirements desired.
A788M, prior to or during the pouring of the ingot, in order to
remove objectionable gases, particularly hydrogen.
4.2 Forging Drawing—Each forging shall be manufactured
Grade 22 Classes 4, 5, 6, and 7 liquid steel shall be produced
in accordance with a purchaser-approved drawing showing the
to a fine grain melting practice which has been shown to result
prequenched dimensions, the finished dimensions, the surfaces
in a prior austenitic grain size of five or finer.
that will be subjected to significant loading, and the locations
5.1.3 Discard—Sufficient discard shall be made from each
of mechanical test specimens.
ingot to secure freedom from piping and excessive segregation.
4.3 Material supplied to this specification shall conform to
5.2 Heat Treatment:
the requirements of Specification A788/A788M, which out-
lines additional ordering information, manufacturing 5.2.1 Preliminary Heat Treatment—After forging and be-
fore reheating, the forgings shall be cooled to provide substan-
requirements, testing and retesting methods and procedures,
marking, certification, product analysis variations, and addi- tially complete transformation of austenite. Preliminary heat
treatment may be applied to improve machinability and to
tional supplementary requirements.
enhance subsequent heat treatments.
5.2.2 Heat Treatment for Mechanical Properties—The forg-
ings shall be heated to a temperature which produces an
austenitic structure and then quenched in a suitable liquid
medium by spraying or immersion. For Grade 4N, Classes 1
Available from American Society of Mechanical Engineers (ASME), ASME
International Headquarters, Two Park Ave., New York, NY 10016-5990, http://
www.asme.org.
TABLE 1 Chemical Requirements
Composition, %
A
Grade 1 Grade 1A Grade 2 Grade 3 Grade 4N Grade 5 Grade 22 Grade 3V Grade 3VCb Grade 6
Carbon 0.35 max 0.30 max 0.27 max 0.25 max 0.23 max 0.23 max 0.11–0.15 0.10–0.15 0.10–0.15 0.28–0.33
Manganese 0.40–1.05 0.70–1.35 0.50–1.00 1.20–1.50 0.20–0.40 0.20–0.40 0.30–0.60 0.30–0.60 0.30–0.60 0.75–1.15
Phosphorus 0.025 max 0.025 max 0.025 max 0.025 max 0.020 max 0.020 max 0.015 max 0.020 max 0.020 max 0.025 max
Sulfur 0.025 max 0.025 max 0.025 max 0.025 max 0.020 max 0.020 max 0.015 max 0.020 max 0.010 max 0.025 max
B
Silicon 0.40 max 0.40 max 0.40 max 0.40 max 0.40 max 0.30 max 0.35 max 0.10 max 0.10 max 0.35 max
Nickel 0.40 max 0.40 max 0.50–1.00 0.40–1.00 2.8–3.9 2.8–3.9 0.25 max . . . 0.25 max 0.75–0.95
Chromium 0.25 max 0.25 max 0.25–0.45 0.25 max 1.50–2.00 1.50–2.00 2.00–2.50 2.8–3.3 2.7–3.3 0.70–1.00
Molybdenum 0.10 max 0.10 max 0.55–0.70 0.45–0.60 0.40–0.60 0.40–0.60 0.90–1.10 max 0.90–1.10 0.90–1.10 0.30–0.45
Vanadium 0.05 max 0.05 max 0.05 max 0.05 max 0.03 max 0.08 max 0.02 max 0.20–0.30 0.20–0.30 0.05 max
C
Columbium 0.01 max 0.01 max 0.01 max 0.01 max 0.01 max 0.01 max 0.01 max 0.01 max 0.015–0.070 0.01 max
Copper 0.20 max 0.20 max 0.20 max 0.20 max 0.25 max 0.25 max 0.25 max 0.25 max 0.25 max 0.25 max
Calcium 0.015 max 0.015 max 0.015 max 0.015 max 0.015 max 0.015 max 0.015 max 0.015 max 0.0005–0.0150 0.015 max
Boron 0.003 max 0.003 max 0.003 max 0.003 max 0.003 max 0.003 max 0.003 max 0.001–0.003 0.003 max 0.003 max
Titanium 0.015 max 0.015 max 0.015 max 0.015 max 0.015 max 0.015 max 0.015 max 0.015–0.035 0.015 max 0.015 max
D
Aluminum 0.030 max 0.030 max 0.030 max 0.030 max 0.025 max 0.025 max 0.025 max 0.015 max 0.015 max 0.025 max
A
For Grade 22 Classes 5, 6, and 7 with section thickness at heat treat of 8 in. or greater, the carbon and manganese shall be held to 0.13 to 0.15 and 0.50 to 0.60,
respectively.
B
When required by the purchaser a minimum silicon content of 0.15 % shall apply for Grades 1, 1A, 2, 3, and 4N.
C
Columbium (Cb) and Niobium (Nb) are alternate names for Element 41 in the Periodic Table of the Elements.
D
Aluminum content reported shall be the combined total soluble and insoluble aluminum.
A508/A508M − 18 (2023)
and 3, the austenitizing temperature shall be 1540 °F [840 °C] within 20 points of the Brinell Hardness of the forging that has
min to 1640 °F [895 °C] max. Quenching shall be followed by been tested for mechanical properties.
tempering at a subcritical temperature and holding at this 7.1.2.2 Forgings or Multiple Forgings (Note 3) with Weight
temperature for a minimum time of one-half hour per inch of at Time of Heat Treatment Not Exceeding 10 000 lb [4540 kg]
maximum section thickness. Except when Supplementary Re- and Having a Heat-Treated Length (Exclusive of Test Prolon-
quirement S 13 is specified for Grades 2 and 3, the minimum gation) of 80 in. [2032 mm] or Less—A test prolongation (Note
tempering temperatures shall be as follows: 4) shall be located at one end. One tension test specimen shall
be taken from the test prolongation.
Grades 1, 1A, 2 Class 2, and 3 Class 2 1150 °F [620 °C]
Grades 2 Class 1 and 3 Class 1 1200 °F [650 °C]
7.1.2.3 Forgings or Multiple Forgings with Weight at Time
Grades 4N Classes 1 and 2, and 5 1100 °F [595 °C]
of Heat Treatment Not Exceeding 10 000 lb [4540 kg] and
Classes 1 and 2
Grade 4N Class 3 1125 °F [605 °C] Having a Heat-Treated Length (Exclusive of Test Prolonga-
Grades 3V and 3VCb 1250 °F [675 °C]
tions) Exceeding 80 in. [2032 mm]—A test prolongation shall
Grade 22, Class 3 1200 °F [650 °C]
be located at each end. One tension test specimen shall be
Grade 22, Classes 4, 5, 6, and 7 1100 °F [593 °C]
taken from each test prolongation. An orientation of 180° shall
Specific cooling rates from the tempering temperature shall
be established between the two tension test specimens.
be applied if Supplementary Requirement S14 is specified.
7.1.2.4 Forgings or Multiple Forgings with Weight at Time
5.3 For Grades 1, 1A, 2, 2A, 3, or 3A, a multiple stage
of Heat Treatment Over 10 000 lb [4540 kg] and Having a
austenitizing procedure may be used whereby the forging is
Heat-Treated Length (Exclusive of Test Prolongation) of 80 in.
first fully austenitized and liquid quenched, followed by
[2032 mm] or Less—A test prolongation shall be located at one
reheating within the intercritical temperature range to partially
end. Two tension test specimens shall be taken from the test
reaustenitize and again liquid quenched. On completion of the
prolongation and shall be oriented 180° apart.
austenitizing/quenching cycles, the forgings shall be tempered
7.1.2.5 Forgings or Multiple Forgings with Weight at Time
at a subcritical temperature as described in 5.2.2.
of Heat Treatment Over 10 000 lb [4540 kg] and Having a
Heat-Treated Length (Exclusive of Test Prolongations) Exceed-
6. Chemical Composition
ing 80 in. [2032 mm]—A test prolongation shall be located at
6.1 Heat Analysis—The heat analysis obtained from sam-
each end. The tension test specimens oriented 180° apart from
pling in accordance with Specification A788/A788M shall
each other shall be taken from each test prolongation. The two
comply with Table 1 except that the additional features of
tension specimens located in one test prolongation shall be
Supplementary Requirements S7, S8, S9, and S11 shall also
oriented 90° in relation to the two tension specimens located in
apply as individually specified in the ordering information.
the other test prolongation.
6.2 Product Analysis—The manufacturer shall use the prod-
NOTE 3—Multiple forgings in 7.1.2.2 through 7.1.2.5 are those which
uct analysis provision of Specification A788/A788M to obtain
will be separated after the quench and temper treatment.
a product analysis from a forging representing each heat or
NOTE 4—A test prolongation is defined as that integral test metal
multiple heat. The permissible variations provided in the table
located at an end of the forging or forging multiples.
on Permissible Variations in Product Analysis for Killed Steel
7.1.3 Samples for mechanical test specimen shall be re-
in Specification A788/A788M apply for manganese, nickel,
moved from forgings after the quenching and tempering heat
chromium, molybdenum, and vanadium only. Boron is not
treatment. The sample material shall be subjected to a simu-
subject to product analysis. The purchaser may also make this
lated post weld heat treatment if Supplementary Requirement
determination in accordance with Specification A788/A788M.
S1 is specified.
7.1.4 For upset disk forgings, the longitudinal axis of the
7. Mechanical Properties
test specimens shall be in the tangential direction. For all other
7.1 Tension Test:
parts, the longitudinal axis of the specimens shall be parallel to
7.1.1 The steel shall conform to the requirements of Ta
...
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: A508/A508M − 18 (Reapproved 2023)
Standard Specification for
Quenched and Tempered Vacuum-Treated Carbon and Alloy
Steel Forgings for Pressure Vessels
This standard is issued under the fixed designation A508/A508M; 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.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope
Grade 5 Class 2 Class 5A
Grade 22 Class 3 Class 22B
1.1 This specification covers quenched and tempered
Grade 22 Classes 4, 5, 6, and 7
vacuum-treated carbon and alloy steel forgings for pressure Grade 3V Class 3V
vessels such as those used in reactor systems. Specifically, it
1.5 This standard does not purport to address all of the
covers forgings for vessel closures, shells, flanges, tube sheets,
safety concerns, if any, associated with its use. It is the
rings, heads, and similar parts.
responsibility of the user of this standard to establish appro-
priate safety, health, and environmental practices and deter-
1.2 All grades are considered weldable under proper condi-
mine the applicability of regulatory limitations prior to use.
tions. Welding technique is of fundamental importance, and it
is presupposed that welding procedure and inspection will be in
1.6 This international standard was developed in accor-
accordance with approved methods for the grade of material dance with internationally recognized principles on standard-
used.
ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom-
1.3 The values stated in either SI units or inch-pound units
mendations issued by the World Trade Organization Technical
are to be regarded separately as standard. The values stated in
Barriers to Trade (TBT) Committee.
each system may not be exact equivalents; therefore, each
system shall be used independently of the other. Combining
2. Referenced Documents
values from the two systems may result in non-conformance
with the standard.
2.1 ASTM Standards:
A275/A275M Practice for Magnetic Particle Examination of
1.4 Unless the order specifies the applicable “M” specifica-
Steel Forgings
tion designation, the material shall be furnished to the inch-
pound units. A370 Test Methods and Definitions for Mechanical Testing
of Steel Products
NOTE 1—Grades 1 and 1A are composed of different chemistries but
A388/A388M Practice for Ultrasonic Examination of Steel
have the same mechanical requirements.
Forgings
NOTE 2—Designations have been changed as follows:
A788/A788M Specification for Steel Forgings, General Re-
Current Formerly
Grade 1 Class 1 quirements
Grade 1A Class 1A
A966/A966M Practice for Magnetic Particle Examination of
Grade 2 Class 1 Class 2
Steel Forgings Using Alternating Current
Grade 2 Class 2 Class 2A
Grade 3 Class 1 Class 3 E208 Test Method for Conducting Drop-Weight Test to
Grade 3 Class 2 Class 3A
Determine Nil-Ductility Transition Temperature of Fer-
Grade 4N Class 1 Class 4
ritic Steels
Grade 4N Class 2 Class 4A
Grade 4N Class 3 Class 4B
E428 Practice for Fabrication and Control of Metal, Other
Grade 5 Class 1 Class 5
than Aluminum, Reference Blocks Used in Ultrasonic
Testing (Withdrawn 2019)
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. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved March 15, 2023. Published April 2023. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 1964. Last previous edition approved in 2018 as A508/A508M – 18. Standards volume information, refer to the standard’s Document Summary page on
DOI: 10.1520/A0508_A0508M-18R23. the ASTM website.
2 4
For ASME Boiler and Pressure Vessel Code applications see related Specifi- The last approved version of this historical standard is referenced on
cation SA-508/SA-508M in Section II of that Code. www.astm.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
A508/A508M − 18 (2023)
2.2 American Society of Mechanical Engineers Standard: 4.3.1 When specified by the purchaser, it is permissible to
Boiler and Pressure Vessel Code—Section III, Articles perform Magnetic particle examination using the AC yoke in
NB 2300, NC 2300, ND 2300, NE 2300, NF 2300, NG accordance with Practice A966/A966M instead of using Prac-
2300 tice A275/A275M (see 9.2.1).
4.4 The optional minimum silicon content as expressed in
3. Terminology
Footnote B to Table 1, if required.
3.1 Definitions:
4.5 If the requirements of this specification are in conflict
3.1.1 controlling cross section thickness (T )—the diameter
C
with the requirements of Specification A788/A788M, the
of the largest theoretical sphere which can be inscribed within
requirements of this specification shall prevail.
the volume of the forging.
5. Materials and Manufacture
4. Ordering Information
5.1 Melting Process:
4.1 Purchase Order—In addition to the ordering informa-
5.1.1 The steel shall be made by the basic electric-furnace
tion required by Specification A788/A788M, the purchaser
process except when secondary ladle refining or the remelting
shall include with the inquiry and order a detailed drawing that
process is employed, in which case the melting processes of
locates the areas of significant loading in the forging (when
Specification A788/A788M are permitted.
required), the method of selecting test locations (see 7.1.5 and
5.1.2 The molten steel shall be vacuum treated in accor-
7.1.6), and purchase options (see 5.2.2, 7.2, and 11.1) and any
dance with the methods described in Specification A788/
supplementary requirements desired.
A788M, prior to or during the pouring of the ingot, in order to
remove objectionable gases, particularly hydrogen.
4.2 Forging Drawing—Each forging shall be manufactured
Grade 22 Classes 4, 5, 6, and 7 liquid steel shall be produced
in accordance with a purchaser-approved drawing showing the
to a fine grain melting practice which has been shown to result
prequenched dimensions, the finished dimensions, the surfaces
in a prior austenitic grain size of five or finer.
that will be subjected to significant loading, and the locations
of mechanical test specimens. 5.1.3 Discard—Sufficient discard shall be made from each
ingot to secure freedom from piping and excessive segregation.
4.3 Material supplied to this specification shall conform to
the requirements of Specification A788/A788M, which out- 5.2 Heat Treatment:
5.2.1 Preliminary Heat Treatment—After forging and be-
lines additional ordering information, manufacturing
requirements, testing and retesting methods and procedures, fore reheating, the forgings shall be cooled to provide substan-
tially complete transformation of austenite. Preliminary heat
marking, certification, product analysis variations, and addi-
tional supplementary requirements. treatment may be applied to improve machinability and to
enhance subsequent heat treatments.
5.2.2 Heat Treatment for Mechanical Properties—The forg-
ings shall be heated to a temperature which produces an
austenitic structure and then quenched in a suitable liquid
medium by spraying or immersion. For Grade 4N, Classes 1
Available from American Society of Mechanical Engineers (ASME), ASME
International Headquarters, Two Park Ave., New York, NY 10016-5990, http://
www.asme.org.
TABLE 1 Chemical Requirements
Composition, %
A
Grade 1 Grade 1A Grade 2 Grade 3 Grade 4N Grade 5 Grade 22 Grade 3V Grade 3VCb Grade 6
Carbon 0.35 max 0.30 max 0.27 max 0.25 max 0.23 max 0.23 max 0.11–0.15 0.10–0.15 0.10–0.15 0.28–0.33
Manganese 0.40–1.05 0.70–1.35 0.50–1.00 1.20–1.50 0.20–0.40 0.20–0.40 0.30–0.60 0.30–0.60 0.30–0.60 0.75–1.15
Phosphorus 0.025 max 0.025 max 0.025 max 0.025 max 0.020 max 0.020 max 0.015 max 0.020 max 0.020 max 0.025 max
Sulfur 0.025 max 0.025 max 0.025 max 0.025 max 0.020 max 0.020 max 0.015 max 0.020 max 0.010 max 0.025 max
B
Silicon 0.40 max 0.40 max 0.40 max 0.40 max 0.40 max 0.30 max 0.35 max 0.10 max 0.10 max 0.35 max
Nickel 0.40 max 0.40 max 0.50–1.00 0.40–1.00 2.8–3.9 2.8–3.9 0.25 max . . . 0.25 max 0.75–0.95
Chromium 0.25 max 0.25 max 0.25–0.45 0.25 max 1.50–2.00 1.50–2.00 2.00–2.50 2.8–3.3 2.7–3.3 0.70–1.00
Molybdenum 0.10 max 0.10 max 0.55–0.70 0.45–0.60 0.40–0.60 0.40–0.60 0.90–1.10 max 0.90–1.10 0.90–1.10 0.30–0.45
Vanadium 0.05 max 0.05 max 0.05 max 0.05 max 0.03 max 0.08 max 0.02 max 0.20–0.30 0.20–0.30 0.05 max
C
Columbium 0.01 max 0.01 max 0.01 max 0.01 max 0.01 max 0.01 max 0.01 max 0.01 max 0.015–0.070 0.01 max
Copper 0.20 max 0.20 max 0.20 max 0.20 max 0.25 max 0.25 max 0.25 max 0.25 max 0.25 max 0.25 max
Calcium 0.015 max 0.015 max 0.015 max 0.015 max 0.015 max 0.015 max 0.015 max 0.015 max 0.0005–0.0150 0.015 max
Boron 0.003 max 0.003 max 0.003 max 0.003 max 0.003 max 0.003 max 0.003 max 0.001–0.003 0.003 max 0.003 max
Titanium 0.015 max 0.015 max 0.015 max 0.015 max 0.015 max 0.015 max 0.015 max 0.015–0.035 0.015 max 0.015 max
D
Aluminum 0.030 max 0.030 max 0.030 max 0.030 max 0.025 max 0.025 max 0.025 max 0.015 max 0.015 max 0.025 max
A
For Grade 22 Classes 5, 6, and 7 with section thickness at heat treat of 8 in. or greater, the carbon and manganese shall be held to 0.13 to 0.15 and 0.50 to 0.60,
respectively.
B
When required by the purchaser a minimum silicon content of 0.15 % shall apply for Grades 1, 1A, 2, 3, and 4N.
C
Columbium (Cb) and Niobium (Nb) are alternate names for Element 41 in the Periodic Table of the Elements.
D
Aluminum content reported shall be the combined total soluble and insoluble aluminum.
A508/A508M − 18 (2023)
and 3, the austenitizing temperature shall be 1540 °F [840 °C] within 20 points of the Brinell Hardness of the forging that has
min to 1640 °F [895 °C] max. Quenching shall be followed by been tested for mechanical properties.
tempering at a subcritical temperature and holding at this 7.1.2.2 Forgings or Multiple Forgings (Note 3) with Weight
temperature for a minimum time of one-half hour per inch of at Time of Heat Treatment Not Exceeding 10 000 lb [4540 kg]
maximum section thickness. Except when Supplementary Re- and Having a Heat-Treated Length (Exclusive of Test Prolon-
quirement S 13 is specified for Grades 2 and 3, the minimum gation) of 80 in. [2032 mm] or Less—A test prolongation (Note
tempering temperatures shall be as follows: 4) shall be located at one end. One tension test specimen shall
be taken from the test prolongation.
Grades 1, 1A, 2 Class 2, and 3 Class 2 1150 °F [620 °C]
Grades 2 Class 1 and 3 Class 1 1200 °F [650 °C]
7.1.2.3 Forgings or Multiple Forgings with Weight at Time
Grades 4N Classes 1 and 2, and 5 1100 °F [595 °C]
of Heat Treatment Not Exceeding 10 000 lb [4540 kg] and
Classes 1 and 2
Grade 4N Class 3 1125 °F [605 °C] Having a Heat-Treated Length (Exclusive of Test Prolonga-
Grades 3V and 3VCb 1250 °F [675 °C]
tions) Exceeding 80 in. [2032 mm]—A test prolongation shall
Grade 22, Class 3 1200 °F [650 °C]
be located at each end. One tension test specimen shall be
Grade 22, Classes 4, 5, 6, and 7 1100 °F [593 °C]
taken from each test prolongation. An orientation of 180° shall
Specific cooling rates from the tempering temperature shall
be established between the two tension test specimens.
be applied if Supplementary Requirement S14 is specified.
7.1.2.4 Forgings or Multiple Forgings with Weight at Time
5.3 For Grades 1, 1A, 2, 2A, 3, or 3A, a multiple stage
of Heat Treatment Over 10 000 lb [4540 kg] and Having a
austenitizing procedure may be used whereby the forging is
Heat-Treated Length (Exclusive of Test Prolongation) of 80 in.
first fully austenitized and liquid quenched, followed by
[2032 mm] or Less—A test prolongation shall be located at one
reheating within the intercritical temperature range to partially
end. Two tension test specimens shall be taken from the test
reaustenitize and again liquid quenched. On completion of the
prolongation and shall be oriented 180° apart.
austenitizing/quenching cycles, the forgings shall be tempered
7.1.2.5 Forgings or Multiple Forgings with Weight at Time
at a subcritical temperature as described in 5.2.2.
of Heat Treatment Over 10 000 lb [4540 kg] and Having a
Heat-Treated Length (Exclusive of Test Prolongations) Exceed-
6. Chemical Composition
ing 80 in. [2032 mm]—A test prolongation shall be located at
6.1 Heat Analysis—The heat analysis obtained from sam-
each end. The tension test specimens oriented 180° apart from
pling in accordance with Specification A788/A788M shall
each other shall be taken from each test prolongation. The two
comply with Table 1 except that the additional features of
tension specimens located in one test prolongation shall be
Supplementary Requirements S7, S8, S9, and S11 shall also
oriented 90° in relation to the two tension specimens located in
apply as individually specified in the ordering information.
the other test prolongation.
6.2 Product Analysis—The manufacturer shall use the prod-
NOTE 3—Multiple forgings in 7.1.2.2 through 7.1.2.5 are those which
uct analysis provision of Specification A788/A788M to obtain
will be separated after the quench and temper treatment.
a product analysis from a forging representing each heat or
NOTE 4—A test prolongation is defined as that integral test metal
multiple heat. The permissible variations provided in the table
located at an end of the forging or forging multiples.
on Permissible Variations in Product Analysis for Killed Steel
7.1.3 Samples for mechanical test specimen shall be re-
in Specification A788/A788M apply for manganese, nickel,
moved from forgings after the quenching and tempering heat
chromium, molybdenum, and vanadium only. Boron is not
treatment. The sample material shall be subjected to a simu-
subject to product analysis. The purchaser may also make this
lated post weld heat treatment if Supplementary Requirement
determination in accordance with Specification A788/A788M.
S1 is specified.
7.1.4 For upset disk forgings, the longitudinal axis of the
7. Mechanical Properties
test specimens shall be in the tangential direction. For all other
7.1 Tension Test:
parts, the longitudinal axis of the specimens shall be parallel to
7.1.1 The steel shall conform to the requirements of Table 2.
the direction of major working of the forging.
7.1.2 The location and number of tension test specimens for
7.
...
This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: A508/A508M − 18 A508/A508M − 18 (Reapproved 2023)
Standard Specification for
Quenched and Tempered Vacuum-Treated Carbon and Alloy
Steel Forgings for Pressure Vessels
This standard is issued under the fixed designation A508/A508M; 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.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope*Scope
1.1 This specification covers quenched and tempered vacuum-treated carbon and alloy steel forgings for pressure vessels such
as those used in reactor systems. Specifically, it covers forgings for vessel closures, shells, flanges, tube sheets, rings, heads, and
similar parts.
1.2 All grades are considered weldable under proper conditions. Welding technique is of fundamental importance, and it is
presupposed that welding procedure and inspection will be in accordance with approved methods for the grade of material used.
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.
1.4 Unless the order specifies the applicable “M” specification designation, the material shall be furnished to the inch-pound units.
NOTE 1—Grades 1 and 1A are composed of different chemistries but have the same mechanical requirements.
NOTE 2—Designations have been changed as follows:
Current Formerly
Grade 1 Class 1
Grade 1A Class 1A
Grade 2 Class 1 Class 2
Grade 2 Class 2 Class 2A
Grade 3 Class 1 Class 3
Grade 3 Class 2 Class 3A
Grade 4N Class 1 Class 4
Grade 4N Class 2 Class 4A
Grade 4N Class 3 Class 4B
Grade 5 Class 1 Class 5
Grade 5 Class 2 Class 5A
Grade 22 Class 3 Class 22B
Grade 22 Classes 4, 5, 6, and 7
Grade 3V Class 3V
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 March 1, 2018March 15, 2023. Published March 2018April 2023. Originally approved in 1964. Last previous edition approved in 20172018 as
A508/A508MA508/A508M – 18.-17. DOI: 10.1520/A0508_A0508M-18.10.1520/A0508_A0508M-18R23.
For ASME Boiler and Pressure Vessel Code applications see related Specification SA-508/SA-508M in Section II of that Code.
*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
A508/A508M − 18 (2023)
1.5 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, health, and environmental practices and determine the applicability of
regulatory limitations prior to use.
1.6 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.
2. Referenced Documents
2.1 ASTM Standards:
A275/A275M Practice for Magnetic Particle Examination of Steel Forgings
A370 Test Methods and Definitions for Mechanical Testing of Steel Products
A388/A388M Practice for Ultrasonic Examination of Steel Forgings
A788/A788M Specification for Steel Forgings, General Requirements
A966/A966M Practice for Magnetic Particle Examination of Steel Forgings Using Alternating Current
E208 Test Method for Conducting Drop-Weight Test to Determine Nil-Ductility Transition Temperature of Ferritic Steels
E428 Practice for Fabrication and Control of Metal, Other than Aluminum, Reference Blocks Used in Ultrasonic Testing
(Withdrawn 2019)
2.2 American Society of Mechanical Engineers Standard:
Boiler and Pressure Vessel Code—Section III, Articles NB 2300, NC 2300, ND 2300, NE 2300, NF 2300, NG 2300
3. Terminology
3.1 Definitions:
3.1.1 controlling cross section thickness (T )—the diameter of the largest theoretical sphere which can be inscribed within the
C
volume of the forging.
4. Ordering Information
4.1 Purchase Order—In addition to the ordering information required by Specification A788/A788M, the purchaser shall include
with the inquiry and order a detailed drawing that locates the areas of significant loading in the forging (when required), the method
of selecting test locations (see 7.1.5 and 7.1.6), and purchase options (see 5.2.2, 7.2, and 11.1) and any supplementary requirements
desired.
4.2 Forging Drawing—Each forging shall be manufactured in accordance with a purchaser-approved drawing showing the
prequenched dimensions, the finished dimensions, the surfaces that will be subjected to significant loading, and the locations of
mechanical test specimens.
4.3 Material supplied to this specification shall conform to the requirements of Specification A788/A788M, which outlines
additional ordering information, manufacturing requirements, testing and retesting methods and procedures, marking, certification,
product analysis variations, and additional supplementary requirements.
4.3.1 When specified by the purchaser, it is permissible to perform Magnetic particle examination using the AC yoke in
accordance with Practice A966/A966M instead of using Practice A275/A275M (see 9.2.1).
4.4 The optional minimum silicon content as expressed in Footnote B to Table 1, if required.
4.5 If the requirements of this specification are in conflict with the requirements of Specification A788/A788M, the requirements
of this specification shall prevail.
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.
The last approved version of this historical standard is referenced on www.astm.org.
Available from American Society of Mechanical Engineers (ASME), ASME International Headquarters, Two Park Ave., New York, NY 10016-5990, http://
www.asme.org.
A508/A508M − 18 (2023)
TABLE 1 Chemical Requirements
Composition, %
A
Grade 1 Grade 1A Grade 2 Grade 3 Grade 4N Grade 5 Grade 22 Grade 3V Grade 3VCb Grade 6
Carbon 0.35 max 0.30 max 0.27 max 0.25 max 0.23 max 0.23 max 0.11–0.15 0.10–0.15 0.10–0.15 0.28–0.33
Manganese 0.40–1.05 0.70–1.35 0.50–1.00 1.20–1.50 0.20–0.40 0.20–0.40 0.30–0.60 0.30–0.60 0.30–0.60 0.75–1.15
Phosphorus 0.025 max 0.025 max 0.025 max 0.025 max 0.020 max 0.020 max 0.015 max 0.020 max 0.020 max 0.025 max
Sulfur 0.025 max 0.025 max 0.025 max 0.025 max 0.020 max 0.020 max 0.015 max 0.020 max 0.010 max 0.025 max
B
Silicon 0.40 max 0.40 max 0.40 max 0.40 max 0.40 max 0.30 max 0.35 max 0.10 max 0.10 max 0.35 max
Nickel 0.40 max 0.40 max 0.50–1.00 0.40–1.00 2.8–3.9 2.8–3.9 0.25 max . . . 0.25 max 0.75–0.95
Chromium 0.25 max 0.25 max 0.25–0.45 0.25 max 1.50–2.00 1.50–2.00 2.00–2.50 2.8–3.3 2.7–3.3 0.70–1.00
Molybdenum 0.10 max 0.10 max 0.55–0.70 0.45–0.60 0.40–0.60 0.40–0.60 0.90–1.10 max 0.90–1.10 0.90–1.10 0.30–0.45
Vanadium 0.05 max 0.05 max 0.05 max 0.05 max 0.03 max 0.08 max 0.02 max 0.20–0.30 0.20–0.30 0.05 max
C
Columbium 0.01 max 0.01 max 0.01 max 0.01 max 0.01 max 0.01 max 0.01 max 0.01 max 0.015–0.070 0.01 max
Copper 0.20 max 0.20 max 0.20 max 0.20 max 0.25 max 0.25 max 0.25 max 0.25 max 0.25 max 0.25 max
Calcium 0.015 max 0.015 max 0.015 max 0.015 max 0.015 max 0.015 max 0.015 max 0.015 max 0.0005–0.0150 0.015 max
Boron 0.003 max 0.003 max 0.003 max 0.003 max 0.003 max 0.003 max 0.003 max 0.001–0.003 0.003 max 0.003 max
Titanium 0.015 max 0.015 max 0.015 max 0.015 max 0.015 max 0.015 max 0.015 max 0.015–0.035 0.015 max 0.015 max
D
Aluminum 0.030 max 0.030 max 0.030 max 0.030 max 0.025 max 0.025 max 0.025 max 0.015 max 0.015 max 0.025 max
A
For Grade 22 Classes 5, 6, and 7 with section thickness at heat treat of 8 in. or greater, the carbon and manganese shall be held to 0.13 to 0.15 and 0.50 to 0.60,
respectively.
B
When required by the purchaser a minimum silicon content of 0.15 % shall apply for Grades 1, 1A, 2, 3, and 4N.
C
Columbium (Cb) and Niobium (Nb) are alternate names for Element 41 in the Periodic Table of the Elements.
D
Aluminum content reported shall be the combined total soluble and insoluble aluminum.
5. Materials and Manufacture
5.1 Melting Process:
5.1.1 The steel shall be made by the basic electric-furnace process except when secondary ladle refining or the remelting process
is employed, in which case the melting processes of Specification A788/A788M are permitted.
5.1.2 The molten steel shall be vacuum treated in accordance with the methods described in Specification A788/A788M, prior to
or during the pouring of the ingot, in order to remove objectionable gases, particularly hydrogen.
Grade 22 Classes 4, 5, 6, and 7 liquid steel shall be produced to a fine grain melting practice which has been shown to result
in a prior austenitic grain size of five or finer.
5.1.3 Discard—Sufficient discard shall be made from each ingot to secure freedom from piping and excessive segregation.
5.2 Heat Treatment:
5.2.1 Preliminary Heat Treatment—After forging and before reheating, the forgings shall be cooled to provide substantially
complete transformation of austenite. Preliminary heat treatment may be applied to improve machinability and to enhance
subsequent heat treatments.
5.2.2 Heat Treatment for Mechanical Properties—The forgings shall be heated to a temperature which produces an austenitic
structure and then quenched in a suitable liquid medium by spraying or immersion. For Grade 4N, Classes 1 and 3, the austenitizing
temperature shall be 1540 °F [840 °C] min to 1640 °F [895 °C] max. Quenching shall be followed by tempering at a subcritical
temperature and holding at this temperature for a minimum time of one-half hour per inch of maximum section thickness. Except
when Supplementary Requirement S 13 is specified for Grades 2 and 3, the minimum tempering temperatures shall be as follows:
Grades 1, 1A, 2 Class 2, and 3 Class 2 1150 °F [620 °C]
Grades 2 Class 1 and 3 Class 1 1200 °F [650 °C]
Grades 4N Classes 1 and 2, and 5 1100 °F [595 °C]
Classes 1 and 2
Grade 4N Class 3 1125 °F [605 °C]
Grades 3V and 3VCb 1250 °F [675 °C]
Grade 22, Class 3 1200 °F [650 °C]
Grade 22, Classes 4, 5, 6, and 7 1100 °F [593 °C]
Specific cooling rates from the tempering temperature shall be applied if Supplementary Requirement S14 is specified.
5.3 For Grades 1, 1A, 2, 2A, 3, or 3A, a multiple stage austenitizing procedure may be used whereby the forging is first fully
A508/A508M − 18 (2023)
austenitized and liquid quenched, followed by reheating within the intercritical temperature range to partially reaustenitize and
again liquid quenched. On completion of the austenitizing/quenching cycles, the forgings shall be tempered at a subcritical
temperature as described in 5.2.2.
6. Chemical Composition
6.1 Heat Analysis—The heat analysis obtained from sampling in accordance with Specification A788/A788M shall comply with
Table 1 except that the additional features of Supplementary Requirements S7, S8, S9, and S11 shall also apply as individually
specified in the ordering information.
6.2 Product Analysis—The manufacturer shall use the product analysis provision of Specification A788/A788M to obtain a
product analysis from a forging representing each heat or multiple heat. The permissible variations provided in the table on
Permissible Variations in Product Analysis for Killed Steel in Specification A788/A788M apply for manganese, nickel, chromium,
molybdenum, and vanadium only. Boron is not subject to product analysis. The purchaser may also make this determination in
accordance with Specification A788/A788M.
7. Mechanical Properties
7.1 Tension Test:
7.1.1 The steel shall conform to the requirements of Table 2.
7.1.2 The location and number of tension test specimens for each forging or multiple forging shall be as follows:
7.1.2.1 Individual Forgings with Weights Not Exceeding 1000 lb [455 kg] or Multiple Forgings Separated into Identical Individual
Forgings with Weights not Exceeding 1000 lb [455 kg] [455 kg] Prior to Quenching and Tempering Treatment—At least one
individual forging from each heat and each heat-treating lot shall be tested using the test specimen locations of 7.1.5 or 7.1.6 as
specified on the purchase orders, except that test specimens located at midlength may be closer to the ends of the production
forging than the specified distance to the second surfaces. All forgings shall be quenched and tempered in the same furnace charge.
All forgings from the multiple shall be Brinell hardness tested after heat treatment and forgings not tested for mechanical properties
shall have a Brinell Hardness within 20 points of the Brinell Hardness of the forging that has been tested for mechanical properties.
7.1.2.2 Forgings or Multiple Forgings (Note 3) with Weight at Time of Heat Treatment Not Exceeding 10 000 lb [4540 kg] and
Having a Heat-Treated Length (Exclusive of Test Prolongation) of 80 in. [2032 mm] or Less—A test prolongation (Note 4) shall
be located at one end. One tension test specimen shall be taken from the test prolongation.
7.1.2.3 Forgings or Multiple Forgings with Weight at Time of Heat Treatment Not Exceeding 10 000 lb [4540 kg] and Having a
Heat-Treated Length (Exclusive of Test Prolongations) Exceeding 80 in. [2032 mm]—A test prolongation shall be located at each
end. One tension test specimen shall be taken from each test prolongation. An orientation of 180° shall be established between the
two tension test specimens.
7.1.2.4 Forgings or Multiple Forgings with Weight at Time of Heat Treatment Over 10 000 lb [4540 kg] and Having a
Heat-Treated Length (Exclusive of Test Prolongation) of 80 in. [2032 mm] or Less—A test prolongation shall be located at one end.
Two tension test specimens shall be taken from the test prolongation and shall
...
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