ASTM A859/A859M-23

Standard Specification for Age-Hardening Alloy Steel Forgings for Pressure Vessel Components

ABSTRACT
This specification covers the standard requirements for low-carbon age-hardened nickel-copper-chromium-molybdenum-columbium alloy steel forgings for pressure vessel components. Materials shall be manufactured to a killed fine austenitic grain size, by vacuum degas melting process. Heat treatment shall be conducted, according to class, by: normalizing and precipitation hardening (Grade A, Class 1); liquid quenching and precipitation hardening (Grade A, Class 2); or double liquid-quenching, tempering, double austenitizing, and precipitation hardening (Grade B). Heat and product analyses shall be used to evaluate the conformance of forgings to required chemical compositions. Tensile, notch toughness, and Charpy impact requirements shall be examined, for which one of four sampling methods may be employed. One tension test and one impact test (for three samples) shall be made for each forging. Dimensions and finishes of the forgings shall conform to that specified by the purchaser. Repair welding shall also be performed only if permitted by the purchaser.
SCOPE
1.1 This specification covers requirements for low-carbon age-hardening nickel-copper-chromium-molybdenum-columbium alloy steel forgings for pressure vessel components.  
1.2 Forgings under this specification are available as Grades A or B. Grade A may be ordered in one or two classes as follows:  
1.2.1 Grade A Class 1—Normalized-and-precipitation-heat-treated, providing a minimum yield strength of 55 ksi [380 MPa] and a minimum tensile strength of 65 ksi [450 MPa].  
1.2.2 Grade A Class 2—Quenched-and-precipitation-heat-treated, providing a minimum yield strength of 65 ksi [450 MPa] and a minimum tensile strength of 75 ksi [515 MPa].  
1.2.3 Grade A was the original steel composition in this specification.  
1.3 Although the material is readily weldable, welding procedures are of fundamental importance and must be such as not to affect adversely the properties of the material, especially in the heat-affected zone. It is presupposed that welding procedures will be suitable for the material being welded.  
1.4 Supplementary requirements, including those applicable in Specification A788/A788M, are provided for use when additional testing or inspection is desired. These shall apply only when specified individually by the purchaser in the order.  
1.5 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system are not necessarily exact equivalents; therefore, to ensure conformance with the standard, each system shall be used independently of the other and values from the two systems shall not be combined.  
1.6 This specification is expressed in both inch-pound and SI units. However, unless the order specifies the applicable “M” specification designation [SI units], the material shall be furnished to inch-pound units.  
1.7 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

• Status: Published
• Publication Date: 31-Oct-2023
• ICS: 77.140.30 - Steels for pressure purposes
• Technical Committee: A01 - Steel, Stainless Steel and Related Alloys
• Drafting Committee: A01.06 - Steel Forgings and Billets

Relations

• Replaces: ASTM A859/A859M-04(2019)e1 - Standard Specification for Age-Hardening Alloy Steel Forgings for Pressure Vessel Components
• Effective Date: 01-Nov-2023
• Refers: ASTM A370-24 - Standard Test Methods and Definitions for Mechanical Testing of Steel Products
• Effective Date: 01-Mar-2024
• Refers: ASTM A275/A275M-23 - Standard Practice for Magnetic Particle Examination of Steel Forgings
• Effective Date: 01-Nov-2023
• Refers: ASTM A370-23 - Standard Test Methods and Definitions for Mechanical Testing of Steel Products
• Effective Date: 15-Sep-2023
• Refers: ASTM A275/A275M-18(2023) - Standard Practice for Magnetic Particle Examination of Steel Forgings
• Effective Date: 01-Mar-2023
• Referred By: ASTM A788/A788M-23 - Standard Specification for Steel Forgings, General Requirements
• Effective Date: 01-Nov-2023

Overview

ASTM A859/A859M-23 is the internationally recognized standard specification developed by ASTM for low-carbon age-hardening alloy steel forgings used in pressure vessel components. This specification outlines requirements for nickel-copper-chromium-molybdenum-columbium alloy steel in both inch-pound and SI units, supporting global harmonization. It covers forging grades, heat treatments, chemical composition, mechanical properties, and testing procedures, ensuring reliable performance for critical pressure vessel applications.

Materials must be vacuum degas melted, achieving a killed fine austenitic grain size. Specific heat treatment classes deliver defined minimum yield and tensile strengths, ensuring the mechanical reliability of forged parts. Supplementary requirements, such as additional testing and inspection procedures, may be included as specified by the purchaser.

Key Topics

• Material Grades and Classes

  • Grade A (Class 1): Normalized and precipitation-hardened (minimum yield: 55 ksi / 380 MPa; tensile: 65 ksi / 450 MPa)
  • Grade A (Class 2): Quenched and precipitation-hardened (minimum yield: 65 ksi / 450 MPa; tensile: 75 ksi / 515 MPa)
  • Grade B: Double quenched, tempered, austenitized, and precipitation hardened

• Chemical Composition

  • Well-defined limits for elements including carbon, manganese, phosphorus, sulfur, silicon, chromium, nickel, molybdenum, copper, columbium, and trace elements

• Manufacturing and Heat Treatment

  • Required vacuum degas melting process
  • Defined normalizing, quenching, tempering, austenitizing, and precipitation hardening protocols per grade/class

• Mechanical and Impact Testing

  • Tensile, notch toughness, and Charpy V-notch impact test criteria
  • Multiple sampling methods based on forging size and configuration

• Testing Methods

  • Product and heat analysis for chemical composition conformance
  • Required reporting of all test outcomes, including methods and heat treatment details

• Welding and Repair

  • Material is weldable; however, welding procedures must not compromise heat-affected zone properties
  • Repair welding is only allowed with purchaser consent and must follow ASME Boiler and Pressure Vessel Code Section IX

Applications

ASTM A859/A859M-23 provides comprehensive requirements for manufacturing alloy steel forgings used in:

• Pressure Vessel Components: Ensuring safety and longevity for parts exposed to high-pressure environments, such as reactors, heat exchangers, storage tanks, and piping systems.
• Industrial and Power Generation: Applied to components within oil and gas processing, petrochemical plants, and power stations requiring high strength, toughness, and resistance to corrosion and embrittlement.
• Heavy Engineering: Valuable for large, complex forged parts where mechanical integrity under cyclic and thermal loads is critical.

Careful adherence to the specifications ensures consistent material performance, safety compliance, and international interoperability in critical infrastructures.

Related Standards

For comprehensive compliance and cross-referencing, users of ASTM A859/A859M-23 should consider the following related standards:

• ASTM A788/A788M - General requirements for steel forgings
• ASTM A370 - Mechanical testing of steel products
• ASTM A275/A275M - Magnetic particle examination of steel forgings
• ASTM A388/A388M - Ultrasonic examination of steel forgings
• ASME Boiler and Pressure Vessel Code - Section IX - Welding qualifications
• ASTM E208 - Drop-weight test for transition temperature
• ASTM E604 - Dynamic tear tests of metallic materials

These referenced specifications ensure that all aspects of pressure vessel alloy steel forging-from raw material selection to manufacturing and inspection-are thoroughly covered, promoting the highest standards of safety and performance in service.

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: A859/A859M − 23
Standard Specification for
Age-Hardening Alloy Steel Forgings for Pressure Vessel
Components
This standard is issued under the fixed designation A859/A859M; 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* 1.6 This specification is expressed in both inch-pound and
SI units. However, unless the order specifies the applicable
1.1 This specification covers requirements for low-carbon
“M” specification designation [SI units], the material shall be
age-hardening nickel-copper-chromium-molybdenum-
furnished to inch-pound units.
columbium alloy steel forgings for pressure vessel compo-
1.7 This international standard was developed in accor-
nents.
dance with internationally recognized principles on standard-
1.2 Forgings under this specification are available as Grades
ization established in the Decision on Principles for the
A or B. Grade A may be ordered in one or two classes as
Development of International Standards, Guides and Recom-
follows:
mendations issued by the World Trade Organization Technical
1.2.1 Grade A Class 1—Normalized-and-precipitation-heat-
Barriers to Trade (TBT) Committee.
treated, providing a minimum yield strength of 55 ksi
[380 MPa] and a minimum tensile strength of 65 ksi
2. Referenced Documents
[450 MPa].
2.1 ASTM Standards:
1.2.2 Grade A Class 2—Quenched-and-precipitation-heat-
A275/A275M Practice for Magnetic Particle Examination of
treated, providing a minimum yield strength of 65 ksi
Steel Forgings
[450 MPa] and a minimum tensile strength of 75 ksi
A370 Test Methods and Definitions for Mechanical Testing
[515 MPa].
of Steel Products
1.2.3 Grade A was the original steel composition in this
A388/A388M Practice for Ultrasonic Examination of Steel
specification.
Forgings
A788/A788M Specification for Steel Forgings, General Re-
1.3 Although the material is readily weldable, welding
quirements
procedures are of fundamental importance and must be such as
E208 Test Method for Conducting Drop-Weight Test to
not to affect adversely the properties of the material, especially
Determine Nil-Ductility Transition Temperature of Fer-
in the heat-affected zone. It is presupposed that welding
ritic Steels
procedures will be suitable for the material being welded.
E604 Test Method for Dynamic Tear Testing of Metallic
1.4 Supplementary requirements, including those applicable
Materials
in Specification A788/A788M, are provided for use when
2.2 ASME Standard:
additional testing or inspection is desired. These shall apply
ASME Boiler and Pressure Vessel Code—Section IX
only when specified individually by the purchaser in the order.
1.5 The values stated in either SI units or inch-pound units
3. Ordering Information and General Requirements
are to be regarded separately as standard. The values stated in
3.1 In addition to the ordering information required by
each system are not necessarily exact equivalents; therefore, to
Specification A788/A788M, the purchaser shall include with
ensure conformance with the standard, each system shall be
the inquiry and order a detailed drawing, sketch, or written
used independently of the other and values from the two
description of the forging and the method of selecting test
systems shall not be combined.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
This specification is under the jurisdiction of ASTM Committee A01 on Steel, contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
Stainless Steel and Related Alloys and is the direct responsibility of Subcommittee Standards volume information, refer to the standard’s Document Summary page on
A01.06 on Steel Forgings and Billets. the ASTM website.
Current edition approved Nov. 1, 2023. Published November 2023. Originally Available from American Society of Mechanical Engineers (ASME), ASME
approved in 1986. Last previous edition approved in 2019 as A859/A859M – 04 International Headquarters, Two Park Ave., New York, NY 10016-5990, http://
ɛ1
(2019) . DOI:10.1520/A0859_A0859M-23. www.asme.org.
*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
A859/A859M − 23
location (see 6.3). When appropriate, the areas of significant 5. Chemical Composition
loading in the forging shall be designated.
5.1 Heat Analysis—The heat analysis obtained from sam-
pling in accordance with Specification A788/A788M shall
3.2 Material supplied to this specification shall conform to
comply with Table 1.
the requirements of Specification A788/A788M, which out-
lines additional ordering information, manufacturing
5.2 Product Analysis—The purchaser may use the product
requirements, testing and retesting methods and procedures,
analysis provision of Specification A788/A788M to obtain a
marking, certification, product analysis variations, and addi-
product analysis from a forging representing each heat or
tional supplementary requirements.
multiple heat.
3.3 If the requirements of this specification are in conflict
6. Mechanical Requirements
with the requirements of Specification A788/A788M, the
requirements of this specification shall prevail.
6.1 Tensile Requirements—The forgings, as represented by
the tension test specimens, shall conform to the requirements
4. Manufacture
of Table 2. The largest obtainable tension test specimen as
specified in Test Methods and Definitions A370 shall be used.
4.1 Melting Practice—The steel shall be made to a killed,
6.2 Notch Toughness Requirements:
fine austenitic grain size, practice.
6.2.1 For Grade A, Class 1 or 2 forgings, unless Supple-
4.1.1 Vacuum degassing in accordance with Specification
mentary Requirement S6 is specified, the Charpy impact test
A788/A788M is highly recommended.
results shall conform to the requirements of Table 3. One set of
4.2 Heat Treatment:
three specimens shall be removed from each specimen location
4.2.1 Normalizing may, at the manufacturer’s option, pre-
as specified in 6.3. The supplier may select a test temperature
cede the prescribed heat treatment cycle.
colder than that specified in the order, but in any case, the
actual test temperature shall be reported with the test results.
4.2.2 Grade A Class 1 forgings shall be normalized at a
6.2.2 For Grade B forgings two sets of Charpy impact
temperature in the range from 1600 °F to 1725 °F [870 °C to
specimens shall be removed from each test specimen location
940 °C] and then precipitation hardened in the range from
as specified in and shall conform to the requirements of Table
1000 °F to 1225 °F [540 °C to 665 °C] for a time to be
3.
determined by the material manufacturer.
6.2.3 Full-size, 10 mm by 10 mm, Charpy V-notch speci-
4.2.3 Grade A Class 2 forgings shall be liquid quenched
mens shall be used unless the material thickness or configura-
from a temperature in the range from 1600 °F to 1725 °F
tion makes it impossible to obtain full-size specimens. If the
[870 °C to 940 °C] and then precipitation hardened in the range
use of sub-size specimens is necessary, the largest standard
from 1000 °F to 1225 °F [540 °C to 665 °C] for a time to be
sub-size specimen it is possible to obtain shall be used.
determined by the material manufacturer.
6.2.4 The acceptance values for sub-size specimens shall be
4.2.4 Grade B forgings shall be double quenched and
reduced in direct ratio to the reduction of specimen width.
tempered (liquid quenched twice) by austenitizing twice at a
temperature in the range of 1600 °F to 1725 °F [870 °C to 6.3 Sampling—The longitudinal axis and the mid-length of
940 °C], and then precipitation hardened at a temperature in tension and impact test specimens shall be positioned in
the range of 1000 °F to 1300 °F [540 °C to 700 °C] for a time accordance with one of the following methods as specified by
to be determined by the manufacturer. the purchaser:
TABLE 1 Chemical Requirements
Composition, %
Element Grade A Grade B
Carbon 0.07 max 0.02–0.04
Manganese 0.40–0.70 0.75–1.05
Phosphorus, max 0.025 0.015
Sulfur, max 0.025 0.002
Silicon, max 0.40 0.40
Chromium 0.60–0.90 0.45–0.75
Nickel 0.70–1.00 3.35–3.85
Molybdenum 0.15–0.25 0.55–0.65
Copper 1.00–1.30 1.15–1.75
Columbium 0.02 min 0.02–0.06
Vanadium max . 0.008
Aluminum max . 0.03
Titanium max . 0.003
Tin max . 0.03
Arsenic max . 0.025
Antimony max . 0.025
Nitrogen . report
A859/A859M − 23
TABLE 2 Tensile Requirements
Property Grade A Grade A
Grade B
Class 1 Class 2
Yield strength 0.2 % offset ksi [MPa] 55 [380 min] 65 [450] min 100–115 [690–800]
Tensile Strength ksi [MPa] 65–85 [450–585] 75–95 [515–650] 105 [725] min
Elongation in 2 in. or 50 mm % min 20 20 16
Reduction of Area % min 45 45 45
TABLE 3 Charpy Impact Requirements
Grade A Grade A
Grade B Grade B
Class 1 Class 2
0 °F [–18 °C] –120 °F [–85 °C]
−50 °F [−45 °C] −50 °F [−45 °C]
A
Test Average, ft/lb [J] 20 [27] 20 [27] 80 [110] 60 [80]
Minimum single value, ft/lb [J] 15 [20] 15 [20] 75 [100] 55 [75]
A
Not more than one specimen from a set may be below this value.
6.3.1 Method 1—This method shall always be used when cracks unless the welded areas are completely removed by
the maximum as-heat-treated thickness does not exceed 2 in. subsequent machining.
[50 mm]. Specimens shall be located in the production forging
6.5 Samples shall be removed from forgings after heat
or test forging (as described in Method 4) at mid-thickness and
treatment. The sample material shall be subjected to a simu-
at least 2 in. [50 mm] from other as-heat-treated surfaces.
lated post-weld heat-treatment if Supplementary Requirement
6.3.2 Method 2—T by 2T, where T is the distance from the
S1 is specified.
area of significant loading (see 3.1) to the nearest as-heat-
treated surface. However, the specimen shall not be nearer to
6.6 Orientation—For upset disk forgings, the longitudinal
one as-heat-treated surface than ⁄4 in. [20 mm] and not nearer
axis of all test specimens shall be oriented in the tangential
than 1 ⁄2 in. [40 mm] to a second as-heat-treated surface. When
direction. For all other forgings, the longitudinal axis of the
this method of testing is employed, forgings are usually
specimens shall be oriented in the direction of maximu
...

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.
´1
Designation: A859/A859M − 04 (Reapproved 2019) A859/A859M − 23
Standard Specification for
Age-Hardening Alloy Steel Forgings for Pressure Vessel
Components
This standard is issued under the fixed designation A859/A859M; 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.
ε NOTE—MPa value was added in 1.2.2 editorially in April 2019.
1. Scope Scope*
1.1 This specification covers requirements for low-carbon age-hardening nickel-copper-chromium-molybdenum-columbium alloy
steel forgings for pressure vessel components.
1.2 Forgings under this specification are available as Grades A or B. Grade A may be ordered in one or two classes as follows:
1.2.1 Grade A Class 1—Normalized-and-precipitation-heat-treated, providing a minimum yield strength of 55 ksi [380 MPa] and
a minimum tensile strength of 65 ksi [450 MPa].
1.2.2 Grade A Class 2—Quenched-and-precipitation-heat-treated, providing a minimum yield strength of 65 ksi [450 MPa] and
a minimum tensile strength of 75 ksi [515 MPa].
1.2.3 Grade A was the original steel composition in this specification.
1.3 Although the material is readily weldable, welding procedures are of fundamental importance and must be such as not to affect
adversely the properties of the material, especially in the heat-affected zone. It is presupposed that welding procedures will be
suitable for the material being welded.
1.4 Supplementary requirements, including those applicable in Specification A788/A788M, are provided for use when additional
testing or inspection is desired. These shall apply only when specified individually by the purchaser in the order.
1.5 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each
system are not necessarily exact equivalents; therefore, to ensure conformance with the standard, each system shall be used
independently of the other and values from the two systems shall not be combined.
1.6 This specification is expressed in both inch-pound and SI units. However, unless the order specifies the applicable “M”
specification designation [SI units], the material shall be furnished to inch-pound units.
1.7 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.
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, 2019Nov. 1, 2023. Published April 2019November 2023. Originally approved in 1986. Last previous edition approved in 20142019
ɛ1
as A859/A859M–04 (2014). – 04 (2019) DOI:10.1520/A0859_A0859M–04R19E01. DOI:10.1520/A0859_A0859M-23.
*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
A859/A859M − 23
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
E208 Test Method for Conducting Drop-Weight Test to Determine Nil-Ductility Transition Temperature of Ferritic Steels
E604 Test Method for Dynamic Tear Testing of Metallic Materials
2.2 ASME Standard:
ASME Boiler and Pressure Vessel Code—Section IX
3. Ordering Information and General Requirements
3.1 In addition to the ordering information required by Specification A788/A788M, the purchaser shall include with the inquiry
and order a detailed drawing, sketch, or written description of the forging and the method of selecting test location (see 6.3). When
appropriate, the areas of significant loading in the forging shall be designated.
3.2 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.
3.3 If the requirements of this specification are in conflict with the requirements of Specification A788/A788M, the requirements
of this specification shall prevail.
4. Manufacture
4.1 Melting Practice—The steel shall be made to a killed, fine austenitic grain size, practice.
4.1.1 Vacuum degassing in accordance with Specification A788/A788M is highly recommended.
4.2 Heat Treatment:
4.2.1 Normalizing may, at the manufacturer’s option, precede the prescribed heat treatment cycle.
4.2.2 Grade A Class 1 forgings shall be normalized at a temperature in the range from 16001600 °F to 1725 °F [870[870 °C to
940 °C] and then precipitation hardened in the range from 10001000 °F to 1225 °F [540[540 °C to 665 °C] for a time to be
determined by the material manufacturer.
4.2.3 Grade A Class 2 forgings shall be liquid quenched from a temperature in the range from 16001600 °F to 1725 °F
[870[870 °C to 940 °C] and then precipitation hardened in the range from 10001000 °F to 1225 °F [540[540 °C to 665 °C] for a
time to be determined by the material manufacturer.
4.2.4 Grade B forgings shall be double quenched and tempered (liquid quenched twice) by austenitizing twice at a temperature
in the range of 16001600 °F to 1725 °F [870[870 °C to 940 °C], and then precipitation hardened at a temperature in the range of
10001000 °F to 1300 °F [540[540 °C to 700 °C] for a time to be determined by the manufacturer.
5. Chemical Composition
5.1 Heat Analysis—The heat analysis obtained from sampling in accordance with Specification A788/A788M shall comply with
Table 1.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Available from American Society of Mechanical Engineers (ASME), ASME International Headquarters, Two Park Ave., New York, NY 10016-5990, http://
www.asme.org.
A859/A859M − 23
TABLE 1 Chemical Requirements
Composition, %
Element Grade A Grade B
Carbon 0.07 max 0.02–0.04
Manganese 0.40–0.70 0.75–1.05
Phosphorus, max 0.025 0.015
Sulfur, max 0.025 0.002
Silicon, max 0.40 0.40
Chromium 0.60–0.90 0.45–0.75
Nickel 0.70–1.00 3.35–3.85
Molybdenum 0.15–0.25 0.55–0.65
Copper 1.00–1.30 1.15–1.75
Columbium 0.02 min 0.02–0.06
Vanadium max . 0.008
Aluminum max . 0.03
Titanium max . 0.003
Tin max . 0.03
Arsenic max . 0.025
Antimony max . 0.025
Nitrogen . report
5.2 Product Analysis—The purchaser may use the product analysis provision of Specification A788/A788M to obtain a product
analysis from a forging representing each heat or multiple heat.
6. Mechanical Requirements
6.1 Tensile Requirements—The forgings, as represented by the tension test specimens, shall conform to the requirements of Table
2. The largest obtainable tension test specimen as specified in Test Methods and Definitions A370 shall be used.
6.2 Notch Toughness Requirements:
6.2.1 For Grade A, Class 1 or 2 forgings, unless Supplementary Requirement S6 is specified, the Charpy impact test results shall
conform to the requirements of Table 3. One set of three specimens shall be removed from each specimen location as specified
in 6.3. The supplier may select a test temperature colder than that specified in the order, but in any case, the actual test temperature
shall be reported with the test results.
6.2.2 For Grade B forgings two sets of Charpy impact specimens shall be removed from each test specimen location as specified
in and shall conform to the requirements of Table 3.
6.2.3 Full-size, 1010 mm by 10 mm, Charpy V-notch specimens shall be used unless the material thickness or configuration makes
it impossible to obtain full-size specimens. If the use of sub-size specimens is necessary, the largest standard sub-size specimen
it is possible to obtain shall be used.
6.2.4 The acceptance values for sub-size specimens shall be reduced in direct ratio to the reduction of specimen width.
6.3 Sampling—The longitudinal axis and the mid-length of tension and impact test specimens shall be positioned in accordance
with one of the following methods as specified by the purchaser:
6.3.1 Method 1—This method shall always be used when the maximum as-heat-treated thickness does not exceed 2 in. [50 mm].
Specimens shall be located in the production forging or test forging (as described in Method 4) at mid-thickness and at least 2 in.
[50 mm] from other as-heat-treated surfaces.
TABLE 2 Tensile Requirements
Property Grade A Grade A
Grade B
Class 1 Class 2
Yield strength 0.2 % offset ksi [MPa] 55 [380 min] 65 [450] min 100–115 [690–800]
Tensile Strength ksi [MPa] 65–85 [450–585] 75–95 [515–650] 105 [725] min
Elongation in 2 in. or 50 mm % min 20 20 16
Reduction of Area % min 45 45 45
A859/A859M − 23
TABLE 3 Charpy Impact Requirements
Grade A Grade A
Grade B Grade B
Class 1 Class 2
0 °F [18 °C][–18 °C] –120 °F [–85 °C]
−50 °F [−45 °C] −50 °F [−45 °C]
A
Test Average, ft/lb [J] 20 [27] 20 [27] 80 [110] 60 [80]
Minimum single value, ft/lb [J] 15 [20] 15 [20] 75 [100] 55 [75]
A
Not more than one specimen from a set may be below this value.
6.3.2 Method 2—T by 2T, where T is the distance from the area of significant loading (see 3.1) to the nearest as-heat-treated
3 1
surface. However, the specimen shall not be nearer to one as-heat-treated surface than ⁄4 in. [20 mm] and not nearer than 1 ⁄2 in.
[40 mm] to a second as-heat-treated surface. When this method of testing is employed, forgings are usually manufactured in
accordance with a purchaser-approved drawing showing pre-heat-treatment dimensions and the location of test specimens.
6.3.3 Method 3— ⁄4T by T, where T is the maximum thickness of the forging as-heat-treated. When this method of testing is
employed for Class 2, the maximum as-heat-treated thickness shall not exceed 8
...