ASTM A320/A320M-22a

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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: A320/A320M − 22 A320/A320M − 22a
Standard Specification for
Alloy-Steel and Stainless Steel Bolting for Low-Temperature
1
Service
This standard is issued under the fixed designation A320/A320M; 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*
2
1.1 This specification covers alloy and stainless steel bolting materials and bolting components for pressure vessels, valves,
flanges, and fittings for low-temperature service. See Specification A962/A962M for the definition of bolting. The bars shall be
hot-wrought and may be further processed by centerless grinding or by cold drawing. Austenitic stainless steel may be solution
annealed or annealed and strain-hardened. When strain hardened austenitic stainless steel is ordered, the purchaser should take
special care to ensure that Appendix X1 is thoroughly understood.
1.2 Several grades are covered, including both ferritic and austenitic steels designated L7, B8, etc. Selection will depend on
design, service conditions, mechanical properties, and low-temperature characteristics. The mechanical requirements of Table 1
indicate the diameters for which the minimum mechanical properties apply to the various grades and classes, and Table 2 stipulates
the requirements for Charpy impact energy absorption. The manufacturer should determine that the material can conform to these
requirements before parts are manufactured. For example, when Grade L43 is specified to meet the Table 2 impact energy values
at −150 °F [−101 °C], additional restrictions (such as procuring a steel with lower P and S contents than might normally be
supplied) in the chemical composition for AISI 4340 are likely to be required.
NOTE 1—The committee formulating this specification has included several grades of material that have been rather extensively used for the present
purpose. Other compositions will be considered for inclusion by the committee from time to time as the need becomes apparent. Users should note that
hardenability of some of the grades mentioned may restrict the maximum size at which the required mechanical properties are obtainable.
1.3 The following referenced general requirements are indispensable for application of this specification: Specification
A962/A962M.
1.4 Nuts for use with bolting are covered in Section 10 and the nut material shall be impact tested.
1.5 Supplementary Requirements are provided for use at the option of the purchaser. The supplementary requirements shall apply
only when specified in the purchase order or contract.
1.6 This specification is expressed in both inch-pound units and SI units; however, unless the purchase order or contract specifies
the applicable M specification designation (SI) units, the inch-pound units shall apply.
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This specification is under the jurisdiction of ASTM Committee A01 on Steel, Stainless Steel and Related Alloys and is the direct responsibility of Subcommittee A01.22
on Steel Forgings and Wrought Fittings for Piping Applications and Bolting Materials for Piping and Special Purpose Applications.
Current edition approved May 1, 2022Nov. 1, 2022. Published June 2022November 2022. Originally approved in 1948. Last previous edition approved in 20212022 as
A320/A320M – 21a.A320/A320M – 22. DOI: 10.1520/A0320_A0320M-22.10.1520/A0320_A0320M-22A.
2
For ASME Boiler and Pressure Vessel Code applications, see related Specification SA-320 in Section II of that Code.
*A Summary of Changes section appears at the end of this standard
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A320/A320M − 22a
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TABLE 1 Mechanical Requirements
Minimum Tensile Yield Strength, Elongation
Reduction
Tempering Strength, min, ksi in 2 in. Hardness,
Class and Grade, Diameter, in. [mm] Heat Treatment of Area,
Temperature, min, ksi [MPa] (0.2 % or 50 max
min, %
°F [°C] [MPa] offset) mm, min, %
Ferritic Steels
L7, L7A, L7B, L7C, L70, L71, L72, L73 125 105 16 50 321 HBW or 35
HRC
A
1
2 ⁄2 [65] and under quenched and tempered 1100 [860] [725]
[593]
L43 125 105 16 50 321 HBW or 35
HRC
A
4 [100] and under quenched and tempered 1100 [860] [725]
[593]
B
L7M 100 80 18 50
...

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation: A320/A320M − 22a
Standard Specification for
Alloy-Steel and Stainless Steel Bolting for Low-Temperature
1
Service
This standard is issued under the fixed designation A320/A320M; 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* 1.3 The following referenced general requirements are in-
2 dispensable for application of this specification: Specification
1.1 This specification covers alloy and stainless steel bolt-
A962/A962M.
ing materials and bolting components for pressure vessels,
valves, flanges, and fittings for low-temperature service. See 1.4 Nuts for use with bolting are covered in Section 10 and
Specification A962/A962M for the definition of bolting. The the nut material shall be impact tested.
bars shall be hot-wrought and may be further processed by
1.5 Supplementary Requirements are provided for use at the
centerless grinding or by cold drawing. Austenitic stainless
option of the purchaser. The supplementary requirements shall
steel may be solution annealed or annealed and strain-
apply only when specified in the purchase order or contract.
hardened. When strain hardened austenitic stainless steel is
1.6 This specification is expressed in both inch-pound units
ordered, the purchaser should take special care to ensure that
and SI units; however, unless the purchase order or contract
Appendix X1 is thoroughly understood.
specifies the applicable M specification designation (SI) units,
1.2 Several grades are covered, including both ferritic and
the inch-pound units shall apply.
austenitic steels designated L7, B8, etc. Selection will depend
1.7 The values stated in either SI units or inch-pound units
on design, service conditions, mechanical properties, and
are to be regarded separately as standard. The values stated in
low-temperature characteristics. The mechanical requirements
each system may not be exact equivalents; therefore, each
of Table 1 indicate the diameters for which the minimum
system shall be used independently of the other. Combining
mechanical properties apply to the various grades and classes,
values from the two systems may result in non-conformance
and Table 2 stipulates the requirements for Charpy impact
with the standard.
energy absorption. The manufacturer should determine that the
material can conform to these requirements before parts are 1.8 This international standard was developed in accor-
dance with internationally recognized principles on standard-
manufactured. For example, when Grade L43 is specified to
meet the Table 2 impact energy values at −150 °F [−101 °C], ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom-
additional restrictions (such as procuring a steel with lower P
and S contents than might normally be supplied) in the mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee.
chemical composition for AISI 4340 are likely to be required.
NOTE 1—The committee formulating this specification has included
2. Referenced Documents
several grades of material that have been rather extensively used for the
3
present purpose. Other compositions will be considered for inclusion by 2.1 ASTM Standards:
the committee from time to time as the need becomes apparent. Users
A194/A194M Specification for Carbon Steel, Alloy Steel,
should note that hardenability of some of the grades mentioned may
and Stainless Steel Nuts for Bolts for High Pressure or
restrict the maximum size at which the required mechanical properties are
High Temperature Service, or Both
obtainable.
A962/A962M Specification for Common Requirements for
Bolting Intended for Use at Any Temperature from Cryo-
genic to the Creep Range
1
This specification is under the jurisdiction of ASTM Committee A01 on Steel,
E566 Practice for Electromagnetic (Eddy Current/Magnetic
Stainless Steel and Related Alloys and is the direct responsibility of Subcommittee
Induction) Sorting of Ferrous Metals
A01.22 on Steel Forgings and Wrought Fittings for Piping Applications and Bolting
Materials for Piping and Special Purpose Applications.
Current edition approved Nov. 1, 2022. Published November 2022. Originally
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approved in 1948. Last previous edition approved in 2022 as A320/A320M – 22. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
DOI: 10.1520/A0320_A0320M-22A. contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
2
For ASME Boiler and Pressure Vessel Code applicatio
...