ASTM A266/A266M-21

Standard Specification for Carbon Steel Forgings for Pressure Vessel Components

ABSTRACT
This specification covers four grades of carbon steel forgings for boiler and pressure vessel components, and associated equipment. Materials shall be manufactured by melting process and hot-worked forging. Heat and product analyses shall be performed wherein forgings shall conform to chemical requirements for carbon, manganese, phosphorus, sulphur, and silicon. Mechanical properties such as tensile strength, yield strength, elongation, and reduction of area shall be inspected as well. The requirements for annealed, normalized, or normalized and tempered steel forgings, and that for quenched and tempered steel forgings have been specified separately.
SCOPE
1.1 This specification2 covers four grades of carbon steel forgings for boilers, pressure vessels, and associated equipment.
Note 1: Designations have been changed as follows:    
Current  
Formerly    
Grade 1  
Class 1  
Grade 2  
Class 2  
Grade 3  
Class 3  
Grade 4  
Class 4  
1.2 Supplementary requirements are provided for use when additional testing or inspection is desired. These shall apply only when specified individually by the purchaser in the order.  
1.3 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system 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.  
1.4 Unless the order specifies the applicable “M” specification designation, the material shall be furnished to the inch-pound units.  
1.5 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: 30-Apr-2021
• ICS: 77.140.30 - Steels for pressure purposes
• ICS: 77.140.85 - Iron and steel forgings
• Technical Committee: A01 - Steel, Stainless Steel and Related Alloys
• Drafting Committee: A01.06 - Steel Forgings and Billets

Relations

• 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 A370-19 - Standard Test Methods and Definitions for Mechanical Testing of Steel Products
• Effective Date: 01-Jul-2019
• Refers: ASTM A788/A788M-19 - Standard Specification for Steel Forgings, General Requirements
• Effective Date: 01-May-2019
• Refers: ASTM A788/A788M-18b - Standard Specification for Steel Forgings, General Requirements
• Effective Date: 01-Nov-2018
• Refers: ASTM A788/A788M-18a - Standard Specification for Steel Forgings, General Requirements
• Effective Date: 01-Sep-2018
• Refers: ASTM A788/A788M-18 - Standard Specification for Steel Forgings, General Requirements
• Effective Date: 01-Mar-2018
• Refers: ASTM A370-17a - Standard Test Methods and Definitions for Mechanical Testing of Steel Products
• Effective Date: 15-Nov-2017
• Refers: ASTM A788/A788M-17a - Standard Specification for Steel Forgings, General Requirements
• Effective Date: 01-Nov-2017
• Refers: ASTM A788/A788M-17 - Standard Specification for Steel Forgings, General Requirements
• Effective Date: 01-May-2017
• Refers: ASTM A370-17 - Standard Test Methods and Definitions for Mechanical Testing of Steel Products
• Effective Date: 01-Jan-2017
• Refers: ASTM A788/A788M-16a - Standard Specification for Steel Forgings, General Requirements
• Effective Date: 01-Dec-2016
• Refers: ASTM A370-15 - Standard Test Methods and Definitions for Mechanical Testing of Steel Products
• Effective Date: 01-Nov-2015
• Refers: ASTM A788/A788M-15 - Standard Specification for Steel Forgings, General Requirements
• Effective Date: 01-May-2015
• Refers: ASTM A788/A788M-14a - Standard Specification for Steel Forgings, General Requirements
• Effective Date: 01-Oct-2014

Overview

ASTM A266/A266M-21 is the internationally recognized standard specification developed by ASTM International for carbon steel forgings used in pressure vessel components. This standard outlines the material, manufacturing, chemical, and mechanical property requirements for four grades of carbon steel forgings primarily intended for use in boilers, pressure vessels, and related equipment. The specification ensures forgings meet strict criteria for performance and safety in critical applications involving high pressure environments.

Key Topics

• Material Coverage: Specifies four grades of carbon steel, with distinct mechanical properties and chemical compositions, suitable for diverse pressure vessel applications.
• Manufacturing Process: Requires steel to be produced through approved melting and hot-working forging processes to ensure integrity and consistency.
• Heat Treatment: Mandates annealing, normalizing, or a combination of normalizing and tempering; alternative quenching and tempering may be allowed upon agreement.
• Chemical Requirements: Forgings must meet strict limits for elements such as carbon, manganese, phosphorus, sulfur, and silicon to ensure material quality and reliability.
• Mechanical Properties: Includes requirements for tensile strength, yield strength, elongation, and reduction of area, verified by mechanical testing post heat-treatment.
• Testing and Inspection: Provides for both heat and product analyses, with supplementary testing and inspection options as specified by purchasers, such as hydrostatic testing, magnetic particle examination, liquid penetrant testing, and macroetch testing.
• Certification and Marking: All forgings must be properly certified, marked with grade and heat treatment indicators, and be traceable to material and test records.

Applications

ASTM A266/A266M-21 is widely applied in industries where pressure vessel integrity is critical. Typical uses include:

• Boilers and Pressure Vessels: Core structural and support components that must withstand high internal pressures and demanding service conditions.
• Nuclear and Fossil Power Plants: Essential for components in energy production that require reliable, high-strength materials.
• Petrochemical and Chemical Processing: Used in reactors, separators, and storage vessels where safety and long-term durability are crucial.
• Associated Pressure Equipment: Such as tube sheets, heads, flanges, and hubs designed for welded or bolted connections in pressurized systems.
• Custom-Forged Pressure Parts: Manufacturers and fabricators use this standard as a basis for selecting and qualifying custom-forged parts for OEM or maintenance applications.

Related Standards

ASTM A266/A266M-21 operates alongside several vital industry standards, including:

• ASTM A788/A788M: General requirements for steel forgings, referenced for ordering, processes, marking, and supplementary requirements.
• ASME Boiler and Pressure Vessel Code (BPVC): Specifically, Section II and IX, which incorporate or reference ASTM standards for construction and qualification.
• ASTM A370: Mechanical testing methods for steel products, used for verifying required mechanical properties.
• ASTM A275/A275M: Standard practice for magnetic particle examination of steel forgings.
• ASTM E112, E165/E165M, and E381: Standards covering grain size determination, liquid penetrant testing, and macroetch testing respectively, supporting compliance with supplementary requirements.

Practical Value

Adhering to ASTM A266/A266M-21 ensures:

• Consistent Material Quality: Strict control of chemical and mechanical properties assures safe, reliable performance in pressurized environments.
• Regulatory Compliance: Meets the demands of global codes, creating a pathway for international trade and project certification.
• Design Confidence: Enables engineers and specifiers to select proven materials for safety-critical applications.
• Traceability and Verification: Requirement for certification and detailed marking supports lifecycle management and accountability.

For manufacturers, engineers, and procurement specialists in the pressure vessel industry, conformance to this standard is essential for safety, compliance, and performance.

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:A266/A266M −21
Standard Specification for
Carbon Steel Forgings for Pressure Vessel Components
This standard is issued under the fixed designationA266/A266M; 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* A275/A275M Practice for Magnetic Particle Examination of
2 Steel Forgings
1.1 This specification covers four grades of carbon steel
A370 Test Methods and Definitions for Mechanical Testing
forgings for boilers, pressure vessels, and associated equip-
of Steel Products
ment.
A788/A788M Specification for Steel Forgings, General Re-
NOTE 1—Designations have been changed as follows:
quirements
Current Formerly
A1058 Test Methods for Mechanical Testing of Steel
Grade 1 Class 1
Products—Metric
Grade 2 Class 2
E112 Test Methods for Determining Average Grain Size
Grade 3 Class 3
Grade 4 Class 4
E165/E165M Practice for Liquid Penetrant Testing for Gen-
1.2 Supplementary requirements are provided for use when eral Industry
E381 Method of Macroetch Testing Steel Bars, Billets,
additional testing or inspection is desired. These shall apply
only when specified individually by the purchaser in the order. Blooms, and Forgings
2.2 Other Standard:
1.3 The values stated in either SI units or inch-pound units
ASME Boiler and Pressure Vessel Code, Section IX
are to be regarded separately as standard. The values stated in
each system are not necessarily exact equivalents; therefore, to
3. Ordering Information and General Requirements
ensure conformance with the standard, each system shall be
3.1 In addition to the ordering information required by
used independently of the other, and values from the two
Specification A788/A788M, the purchaser shall include with
systems shall not be combined.
the inquiry and order a detailed drawing, sketch, or written
1.4 Unless the order specifies the applicable “M” specifica- description of the forging.
tion designation, the material shall be furnished to the inch-
3.2 Material supplied to this specification shall conform to
pound units.
the requirements of Specification A788/A788M, which out-
1.5 This international standard was developed in accor-
lines additional ordering information, manufacturing
dance with internationally recognized principles on standard-
requirements, testing and retesting methods and procedures,
ization established in the Decision on Principles for the
marking, certification, product analysis variations, and addi-
Development of International Standards, Guides and Recom-
tional supplementary requirements.
mendations issued by the World Trade Organization Technical
3.3 If the requirements of this specification are in conflict
Barriers to Trade (TBT) Committee.
with the requirements of Specification A788/A788M, the
requirements of this specification shall prevail.
2. Referenced Documents
3 3.4 ForhubbedflatheadsandtubesheetsorderedforASME
2.1 ASTM Standards:
Boiler and Pressure Vessel Code application, Supplementary
Requirement S12 of Specification A788/A788M shall be
This specification is under the jurisdiction ofASTM Committee A01 on Steel,
specified in addition to Supplementary Requirement S8 of this
Stainless Steel and Related Alloys and is the direct responsibility of Subcommittee
specification.
A01.06 on Steel Forgings and Billets.
Current edition approved May 1, 2021. Published May 2021. Originally
4. Materials and Manufacture
approved in 1943. Last previous edition approved in 2020 as A266/A266M – 20.
DOI: 10.1520/A0266_A0266M-21.
4.1 The steel shall be made in accordance with the Melting
For ASME Boiler and Pressure Vessel Code applications, see related Specifi-
Process Section of Specification A788/A788M. A sufficient
cation SA–266/SA–266M in Section II of that code.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Available from American Society of Mechanical Engineers (ASME), ASME
Standards volume information, refer to the standard’s Document Summary page on International Headquarters, Two Park Ave., New York, NY 10016-5990, http://
the ASTM website. 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
A266/A266M−21
discard shall be made to secure freedom from injurious pipe 8. Mechanical Properties
and undue segregation.
8.1 General Requirements—Except when otherwise speci-
4.2 The material shall be forged as close as practical to the fied in accordance with Supplementary Requirement S2, the
specified shape and size. material shall conform to the requirements for mechanical
propertiesprescribedinTable2whentestedinaccordancewith
4.3 The finished product shall be a hot-worked forging as
the latest issue of Test Methods and Definitions A370 or Test
defined by Specification A788/A788M.
MethodsA1058whentheMsuffixstandardhasbeenspecified.
ThelargestobtainabletensiontestspecimenasspecifiedinTest
5. Machining
Methods and Definitions A370 or Test Methods A1058,as
5.1 Surfaces shall be machined as designated by the pur-
applicable, shall be used.
chaser. Unmachined surfaces shall be sufficiently free of scale
8.1.1 Except when otherwise specified in accordance with
to permit inspection.
Supplementary Requirement S2, the longitudinal axis of the
5.2 Machiningmaybeperformedeitherpriortoorafterheat
specimensshallbeparalleltothedirectionofmajorworkingof
treatment at the option of the manufacturer unless specified in
theforging.Forupset-discforgings,thelongitudinalaxisofthe
accordance with Supplementary Requirement S1.
test specimen shall be in the tangential direction.
8.1.1.1 The longitudinal axis of the specimen shall be
6. Heat Treatment
located midway between the parallel surfaces of the test
6.1 After forging and before reheating for heat treatment, extensionifaddedtotheperipheryofdisksormidwaybetween
the forgings shall be cooled in such a manner as to prevent thecenterandsurfaceofsolidforgings.Forhollowforgings,or
injury and to accomplish transformation. those heat-treated after boring, the specimen shall be located at
midwall. For the special case of forgings that are heat-treated
6.2 All forgings shall be annealed, normalized, or normal-
solid, but are subsequently bored, the tension test specimen
ized and tempered, but alternatively may be liquid quenched
may be taken at the location of the minimum inside diameter
and tempered when mutually agreed upon between the manu-
after boring instead of the mid-radius position. When sepa-
facturer and the purchaser. When tempering is performed, it
rately forged test blocks are employed as defined in 8.1.3, the
shall be at a subcritical temperature, but no less than 1100 °F
tension test specimens shall be taken from a location that
[595 °C].
representsthemidwalloftheheaviestsectionoftheproduction
6.3 A multiple stage austenitizing procedure may be used
forgings. When specimens are required from opposite ends,
whereby the forging is first fully austenitized and liquid
they shall be taken from the diagonal corners of an axial plane.
quenched, followed by reheating within the intercritical tem-
8.1.2 Except as specified herein, tests for acceptance shall
perature range to partially reaustenitize, and again liquid
be made after heat treatment has been completed. When the
quenched. On completion of the austenitizing/quenching
ends of the cylindrical forgings are closed in by reforging, the
cycles, tempering at a temperature between 1100 °F [595 °C]
cylindrical forgings may be annealed, normalized, or normal-
and the lower critical temperature shall follow.
ized and tempered and tested prior to reforging. After
reforging, the entire forging shall be reheat-treated in the same
NOTE 2—Although liquid quenching from the austenitizing tempera-
turesismoreeffectiveinenhancingimpactproperties,aircoolingfromthe
manner and at the same temperature range as employed when
austenitizing temperatures is also beneficial and may be used instead of
the forging was heat-treated prior to certification testing.
the normalizing procedure in 6.2.
8.1.3 When mutually agreed upon between manufacturer
and purchaser, test specimens may be machined from a
7. Chemical Composition
specially forged block suitably worked and heat-treated with
7.1 Heat Analysis—The heat analysis obtained from sam-
the production forgings. Such a special block shall be obtained
pling in accordance with Specification A788/A788M shall
from an ingot, slab, or billet from the same heat used to make
comply with Table 1 except that the additional features of
the forgings it represents. This block shall receive essentially
Supplementary Requirements S11 and S12 shall also apply as
the same type of hot working and forging reduction as the
individually specified in the ordering information.
production forgings; however, a longitudinally forged bar with
7.2 Product Analysis—The purchaser may use the product
dimensionsnotlessthan Tby Tby3Tmaybeusedtorepresent
analysis provision of Specification A788/A788M to obtain a a ring forging. The dimension T shall be representative of the
product analysis from a forging representing each heat or
heaviest effective cross section of the forging. For quenched
multiple heat.
TABLE 2 Tensile Requirements
Grades
TABLE 1 Chemical Requirements
Grade 1 Grade 3
2 and 4
Composition, %
Tensile strength, min, ksi [MPa] 60–85 70–95 75–100
Grades 1 and 2 Grade 3 Grade 4
[415–585] [485–655] [515–690]
Carbon, max 0.30 0.35 0.30 Yield strength (0.2 % offset), 30 [205] 36
...

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: A266/A266M − 20 A266/A266M − 21
Standard Specification for
Carbon Steel Forgings for Pressure Vessel Components
This standard is issued under the fixed designation A266/A266M; 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*
1.1 This specification covers four grades of carbon steel forgings for boilers, pressure vessels, and associated equipment.
NOTE 1—Designations have been changed as follows:
Current Formerly
Grade 1 Class 1
Grade 2 Class 2
Grade 3 Class 3
Grade 4 Class 4
1.2 Supplementary requirements are provided for use when additional testing or inspection is desired. These shall apply only when
specified individually by the purchaser in the order.
1.3 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each
system mayare not benecessarily exact equivalents; therefore, to ensure conformance with the standard, each system shall be used
independently of the other. Combiningother, and values from the two systems may result in non-conformance with the
standard.shall not be combined.
1.4 Unless the order specifies the applicable “M” specification designation, the material shall be furnished to the inch-pound units.
1.5 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
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 Nov. 1, 2020May 1, 2021. Published November 2020May 2021. Originally approved in 1943. Last previous edition approved in 20182020 as
A266/A266M – 18.A266/A266M – 20. DOI: 10.1520/A0266_A0266M-20.10.1520/A0266_A0266M-21.
For ASME Boiler and Pressure Vessel Code applications, see related Specification SA–266/SA–266M in Section II of that code.
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.
*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
A266/A266M − 21
A788/A788M Specification for Steel Forgings, General Requirements
A1058 Test Methods for Mechanical Testing of Steel Products—Metric
E112 Test Methods for Determining Average Grain Size
E165/E165M Practice for Liquid Penetrant Testing for General Industry
E381 Method of Macroetch Testing Steel Bars, Billets, Blooms, and Forgings
2.2 Other 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.
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.
3.4 For hubbed flat heads and tube sheets ordered for ASME Boiler and Pressure Vessel Code application, Supplementary
Requirement S12 of Specification A788/A788M shall be specified in addition to Supplementary Requirement S8 of this
specification.
4. Materials and Manufacture
4.1 The steel shall be made in accordance with the Melting Process Section of Specification A788/A788M. A sufficient discard
shall be made to secure freedom from injurious pipe and undue segregation.
4.2 The material shall be forged as close as practical to the specified shape and size.
4.3 The finished product shall be a hot-worked forging as defined by Specification A788/A788M.
5. Machining
5.1 Surfaces shall be machined as designated by the purchaser. Unmachined surfaces shall be sufficiently free of scale to permit
inspection.
5.2 Machining may be performed either prior to or after heat treatment at the option of the manufacturer unless specified in
accordance with Supplementary Requirement S1.
6. Heat Treatment
6.1 After forging and before reheating for heat treatment, the forgings shall be cooled in such a manner as to prevent injury and
to accomplish transformation.
6.2 All forgings shall be annealed, normalized, or normalized and tempered, but alternatively may be liquid quenched and
tempered when mutually agreed upon between the manufacturer and the purchaser. When tempering is performed, it shall be at
a subcritical temperature, but no less than 1100 °F [595 °C].
6.3 A multiple stage austenitizing procedure may be used whereby the forging is first fully austenitized and liquid quenched,
Available from American Society of Mechanical Engineers (ASME), ASME International Headquarters, Two Park Ave., New York, NY 10016-5990, http://
www.asme.org.
A266/A266M − 21
followed by reheating within the intercritical temperature range to partially reaustenitize, and again liquid quenched. On
completion of the austenitizing/quenching cycles, tempering at a temperature between 1100 °F [595 °C] and the lower critical
temperature shall follow.
NOTE 2—Although liquid quenching from the austenitizing temperatures is more effective in enhancing impact properties, air cooling from the
austenitizing temperatures is also beneficial and may be used instead of the normalizing procedure in 6.2.
7. Chemical Composition
7.1 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 S11 and S12 shall also apply as individually specified
in the ordering information.
7.2 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.
8. Mechanical Properties
8.1 General Requirements—Except when otherwise specified in accordance with Supplementary Requirement S2, the material
shall conform to the requirements for mechanical properties prescribed in Table 2 when tested in accordance with the latest issue
of Test Methods and Definitions A370 or Test Methods A1058 when the M suffix standard has been specified. The largest
obtainable tension test specimen as specified in Test Methods and Definitions A370 or Test Methods A1058, as applicable, shall
be used.
8.1.1 Except when otherwise specified in accordance with Supplementary Requirement S2, the longitudinal axis of the specimens
shall be parallel to the direction of major working of the forging. For upset-disc forgings, the longitudinal axis of the test specimen
shall be in the tangential direction.
8.1.1.1 The longitudinal axis of the specimen shall be located midway between the parallel surfaces of the test extension if added
to the periphery of disks or midway between the center and surface of solid forgings. For hollow forgings, the longitudinal axis
of the specimens or those heat-treated after boring, the specimen shall be located midway between the center and outer surfaces
of the wall. at midwall. For the special case of forgings that are heat-treated solid, but are subsequently bored, the tension test
specimen may be taken at the location of the minimum inside diameter after boring instead of the mid-radius position. When
separately forged test blocks are employed as defined in 8.1.3, the tension test specimens shall be taken from a location that
represents the midwall of the heaviest section of the production forgings. When specimens are required from opposite ends, they
shall be taken from the diagonal corners of an axial plane.
8.1.2 Except as specified herein, tests for acceptance shall be made after heat treatment has been completed. When the ends of
the cylindrical forgings are closed in by reforging, the cylindrical forgings may be annealed, normalized, or normalized and
tempered and tested prior to reforging. After reforging, the entire forging shall be reheat-treated in the same manner and at the same
temperature range as employed when the forging was heat-treated prior to certification testing.
8.1.3 When mutually agreed upon between manufacturer and purchaser, test specimens may be machined from a specially forged
block suitably worked and heat treated heat-treated with the production forgings. Such a special block shall be obtained from an
ingot, slab, or billet from the same heat used to make the forgings it represents. This block shall receive essentially the same type
of hot working and forging reduction as the production forgings; however, a longitudinally forged bar with dimensions not less
than T by T by 3T may be used to represent a ring forging. The dimension T shall be representative of the heaviest effective cross
section of the forging. For quenched and tempered forgings for which tests are required at both ends by 8.2.2.3 and 8.2.2.4,
separately forged test blocks are not allowed.
TABLE 1 Chemical Requirements
Composition, %
...