ASTM A668/A668M-16
(Specification)Standard Specification for Steel Forgings, Carbon and Alloy, for General Industrial Use
Standard Specification for Steel Forgings, Carbon and Alloy, for General Industrial Use
ABSTRACT
This specification deals with the standard requirements for untreated and heat-treated carbon and alloy steel forgings for general industrial use. This specification covers six classes of carbon steels (Class A to F) and seven classes of alloy steels (Class G, H, and J to N). Materials shall be forged by hot mechanical work. Except for Class A, all forgings shall be heat treated, depending on class, by the following techniques: annealed, or normalized, or normalized and tempered (Classes B, C, D, and G); normalized and tempered, or double-normalized and tempered (Class E); quenched and tempered, or normalized, quenched, and tempered (Classes F); normalized and tempered (Class H); normalized and tempered, or normalized, quenched, and tempered (Class J); and normalized, quenched, and tempered (Classes K, L, M, and N). Steel specimens shall undergo heat and product analyses, and shall conform to required chemical compositions for manganese, phosphorus, and sulfur. Steel forgings shall also be tested on their conformance to the following tensile requirements: tensile strength, yield point, yield strength, elongation, reduction of area, and Brinell hardness.
SCOPE
1.1 This specification covers untreated and heat-treated carbon and alloy steel forgings for general industrial use. Other ASTM specifications for forgings are available for specific applications such as pressure vessels, railroad use, turbine generators, gearing, and others involving special temperature requirements.
1.2 Hot-rolled or cold finished bars are not within the scope of this specification.
1.3 Six classes of carbon steel and seven classes of alloy steel forgings are listed (see Section 7), which indicates their required heat treatments, as well as mechanical properties.
1.4 Provision, with the suffix H for certification and marking, for the supply of forgings after hardness testing only.
1.5 Supplementary requirements, including those in Specification A788/A788M, of an optional nature are provided. These shall apply only when specified by the purchaser.
1.6 Appendix X1 lists the current classes corresponding to the various classes of Specifications A235, A237, and A243, which have been superseded by this specification.
1.7 The values stated in either SI units or inch-pound units are to be regarded separately as standard; within the text and tables, the SI units are shown in brackets. 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 nonconformance with the standard.
1.8 Unless the order specifies the applicable "M" specification, the forgings shall be furnished to the inch-pound units.
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Designation:A668/A668M −16 American Association State
Highway and Transportation Officials Standard
AASHTO No.: M 102
Standard Specification for
Steel Forgings, Carbon and Alloy, for General Industrial
1
Use
This standard is issued under the fixed designationA668/A668M; the number immediately following the designation indicates the year
of original adoption or, in the case of revision, the year of last revision.Anumber 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* 2. Referenced Documents
2
2.1 ASTM Standards:
1.1 This specification covers untreated and heat-treated
carbonandalloysteelforgingsforgeneralindustrialuse.Other A275/A275MPracticeforMagneticParticleExaminationof
Steel Forgings
ASTM specifications for forgings are available for specific
applications such as pressure vessels, railroad use, turbine A370Test Methods and Definitions for Mechanical Testing
of Steel Products
generators, gearing, and others involving special temperature
requirements. A388/A388MPractice for Ultrasonic Examination of Steel
Forgings
1.2 Hot-rolled or cold finished bars are not within the scope
A788/A788MSpecification for Steel Forgings, General Re-
of this specification.
quirements
1.3 Six classes of carbon steel and seven classes of alloy
E290Test Methods for Bend Testing of Material for Ductil-
steel forgings are listed (see Section 7), which indicates their
ity
required heat treatments, as well as mechanical properties.
E340Practice for Macroetching Metals and Alloys
1.4 Provision, with the suffix H for certification and
3. Terminology
marking, for the supply of forgings after hardness testing only.
3.1 The terminology section of Specification A788/A788M
1.5 Supplementary requirements, including those in Speci-
is applicable to this specification.
fication A788/A788M, of an optional nature are provided.
These shall apply only when specified by the purchaser.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 class—a description of steel forgings based on heat
1.6 Appendix X1 lists the current classes corresponding to
treatment, mechanical properties and composition.
the various classes of Specifications A235, A237, and A243,
which have been superseded by this specification. 3.2.2 controlling cross section thickness (T )—the diameter
C
of the largest theoretical sphere which can be inscribed within
1.7 The values stated in either SI units or inch-pound units
the volume of the forging.
are to be regarded separately as standard; within the text and
3.2.3 T —designates prolongations which have a size other
tables, the SI units are shown in brackets. The values stated in
P
than the controlling cross section thickness (T ).
each system may not be exact equivalents; therefore, each
C
system shall be used independently of the other. Combining
4. Ordering Information and General Requirements
values from the two systems may result in nonconformance
with the standard.
4.1 Material supplied to this specification shall conform to
therequirementsofSpecificationA788/A788Mwhichoutlines
1.8 Unless the order specifies the applicable "M"
additional ordering information, manufacturing requirements,
specification, the forgings shall be furnished to the inch-pound
testing and retesting methods and procedures, marking,
units.
certification, product analysis variations and additional supple-
mentary requirements.
1
This specification is under the jurisdiction ofASTM Committee A01 on Steel,
Stainless Steel and RelatedAlloys and is the direct responsibility of Subcommittee
2
A01.06 on Steel Forgings and Billets. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved May 1, 2016. Published May 2016. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 1972. Last previous edition approved in 2015 as A668/A668M–15. Standards volume information, refer to the standard’s Document Summary page on
DOI: 10.1520/A0668_A0668M-16. 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
1
---------------------- Page: 1 ----------------------
A668/A668M−16
4.1.1 If the requirements of this specification are in conflict 7.1.3 Number of Tests—Unless the purchaser specifies that
with the requirements of Specification A788/A788M, the forgingsshallbefurnishedinaccordancewiththerequirements
requirements of this specification shall prevail. of 7.3, the number of tension tests performed shall be as
follows:
4.2 When this specification is to be applied to an inquiry,
7.1.3.1 For all classes of heat-treated
...
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: A668/A668M − 15 A668/A668M − 16 American Association State
Highway and Transportation Officials Standard
AASHTO No.: M 102
Standard Specification for
Steel Forgings, Carbon and Alloy, for General Industrial
1
Use
This standard is issued under the fixed designation A668/A668M; 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 untreated and heat-treated carbon and alloy steel forgings for general industrial use. Other ASTM
specifications for forgings are available for specific applications such as pressure vessels, railroad use, turbine generators, gearing,
and others involving special temperature requirements.
1.2 Hot-rolled or cold finished bars are not within the scope of this specification.
1.3 Six classes of carbon steel and seven classes of alloy steel forgings are listed (see Section 7), which indicates their required
heat treatments, as well as mechanical properties.
1.4 Provision, with the suffix H for certification and marking, for the supply of forgings after hardness testing only.
1.5 Supplementary requirements, including those in Specification A788/A788M, of an optional nature are provided. These shall
apply only when specified by the purchaser.
1.6 Appendix X1 lists the current classes corresponding to the various classes of Specifications A235, A237, and A243, which
have been superseded by this specification.
1.7 The values stated in either SI units or inch-pound units are to be regarded separately as standard; within the text and tables,
the SI units are shown in brackets. 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 nonconformance with the standard.
1.8 Unless the order specifies the applicable "M" specification, the forgings shall be furnished to the inch-pound units.
2. Referenced Documents
2
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
E290 Test Methods for Bend Testing of Material for Ductility
E340 Practice for Macroetching Metals and Alloys
3. Terminology
3.1 The terminology section of Specification A788/A788M is applicable to this specification.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 class—a description of steel forgings based on heat treatment, mechanical properties and composition.
1
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, 2015May 1, 2016. Published March 2015May 2016. Originally approved in 1972. Last previous edition approved in 20142015 as
A668/A668M– 14.– 15. DOI: 10.1520/A0668_A0668M-15.10.1520/A0668_A0668M-16.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM 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
1
---------------------- Page: 1 ----------------------
A668/A668M − 16
3.2.2 controlling cross section thickness (T )—the diameter of the largest theoretical sphere which can be inscribed within the
C
volume of the forging.
3.2.3 T —designates prolongations which have a size other than the controlling cross section thickness (T ).
P C
4. Ordering Information and General Requirements
4.1 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.
4.1.1 If the requirements of this specification are in conflict wit
...
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