ASTM F879-23
(Specification)Standard Specification for Stainless Steel Socket Button, Low and Flat Countersunk Head Cap Screws
Standard Specification for Stainless Steel Socket Button, Low and Flat Countersunk Head Cap Screws
ABSTRACT
This specification covers the chemical and mechanical requirements for stainless steel metric hexagon socket button (SBHCS) and flat countersunk (SFHCS) head cap screws with nominal thread M 3 through M 20 intended for use in applications requiring general corrosion resistance. These steels are designated into three classes: Austenitic Class A 1-50 in an annealed condition, Austenitic Class A1-55 in a cold worked condition, and Austenitic Class A 1-70 in a cold worked condition. The austenitic stainless steel socket screw shall be designated F879M A1-50, F879M A1–55, or F 879M A1-70. Screws shall be formed by upsetting or extruding, or both. Also, these screws shall be roll threaded. Austenitic alloys ClassA 1-50 screws, following manufacture, shall be annealed by heating to a certain temperature to obtain maximum corrosion resistance and minimum permeability. The screws shall be held for a sufficient time at temperature, then cooled at a rate sufficient to prevent precipitation of the carbide and provide the properties specified. Different tests shall be conducted in order to determine the following mechanical properties of screws: tensile strength, minimum extension, yield strength, elongation, Vickers hardness, and Rockwell hardness.
SCOPE
1.1 This specification covers the chemical and mechanical requirements for stainless steel inch hexagon socket button (SBHCS), flat countersunk (SFHCS) head cap screws with nominal thread 0.060 through 0.625 in. and low head (SLHCS) cap screws with nominal thread 0.112 through 0.625 in. intended for use in applications requiring general corrosion resistance.
1.2 Two groups of austenitic stainless steel alloys and three conditions are covered. See Table 1 and Table 2.
1.3 Units—The values stated in inch-pound units are to be regarded as standard. No other units of measurement are included in this standard.
1.4 The following precautionary caveat pertains only to the test method portion, Section 12, of this specification: 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.
1.5 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.
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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: F879 − 23
Standard Specification for
Stainless Steel Socket Button, Low and Flat Countersunk
1
Head Cap Screws
This standard is issued under the fixed designation F879; 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* Attack in Austenitic Stainless Steels
A342/A342M Test Methods for Permeability of Weakly
1.1 This specification covers the chemical and mechanical
Magnetic Materials
requirements for stainless steel inch hexagon socket button
A380/A380M Practice for Cleaning, Descaling, and Passi-
(SBHCS), flat countersunk (SFHCS) head cap screws with
vation of Stainless Steel Parts, Equipment, and Systems
nominal thread 0.060 through 0.625 in. and low head (SLHCS)
A555/A555M Specification for General Requirements for
cap screws with nominal thread 0.112 through 0.625 in.
Stainless Steel Wire and Wire Rods
intended for use in applications requiring general corrosion
A751 Test Methods and Practices for Chemical Analysis of
resistance.
Steel Products
1.2 Two groups of austenitic stainless steel alloys and three
A967/A967M Specification for Chemical Passivation Treat-
conditions are covered. See Table 1 and Table 2.
ments for Stainless Steel Parts
D3951 Practice for Commercial Packaging
1.3 Units—The values stated in inch-pound units are to be
regarded as standard. No other units of measurement are E18 Test Methods for Rockwell Hardness of Metallic Ma-
terials
included in this standard.
E92 Test Methods for Vickers Hardness and Knoop Hard-
1.4 The following precautionary caveat pertains only to the
ness of Metallic Materials
test method portion, Section 12, of this specification: This
E384 Test Method for Microindentation Hardness of Mate-
standard does not purport to address all of the safety concerns,
rials
if any, associated with its use. It is the responsibility of the user
F593 Specification for Stainless Steel Bolts, Hex Cap
of this standard to establish appropriate safety, health, and
Screws, and Studs
environmental practices and determine the applicability of
F606/F606M Test Methods for Determining the Mechanical
regulatory limitations prior to use.
Properties of Externally and Internally Threaded
1.5 This international standard was developed in accor-
Fasteners, Washers, Direct Tension Indicators, and Rivets
dance with internationally recognized principles on standard-
F788 Specification for Surface Discontinuities of Bolts,
ization established in the Decision on Principles for the
Screws, Studs, and Rivets, Inch and Metric Series
Development of International Standards, Guides and Recom-
F1470 Practice for Fastener Sampling for Specified Me-
mendations issued by the World Trade Organization Technical
chanical Properties and Performance Inspection
Barriers to Trade (TBT) Committee.
2.2 ASME Standard:
3
B 18.3 Socket Cap, Shoulder and Set Screws (Inch Series)
2. Referenced Documents
4
2.3 JIS Standard:
2
2.1 ASTM Standards:
JIS G 4309 Stainless Steel Wires
A262 Practices for Detecting Susceptibility to Intergranular
3. Classification
3.1 The designation of the alloy group and condition of this
1
This specification is under the jurisdiction of ASTM Committee F16 on
specification shall be consistent with the stainless steel desig-
Fasteners and is the direct responsibility of Subcommittee F16.04 on Nonferrous
Fasteners. nations in Specification F593.
Current edition approved June 1, 2023. Published July 2023. Originally approved
in 1986. Last previous edition approved in 2020 as F879 – 15 (2020). DOI:
3
10.1520/F0879-23. Available from American Society of Mechanical Engineers (ASME), ASME
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or International Headquarters, Two Park Ave., New York, NY 10016-5990, http://
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM www.asme.org.
4
Standards volume information, refer to the standard’s Document Summary page on Available from Japanese Industrial Standards Committee (JIS) 1-3-1
the ASTM website. Kasumigaseki, Chiyoda-ku, Tokyo 100-8901, JAPAN. http://www.jisc.go.jp
*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
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F879 − 23
TABLE 1 Mechanical Property Requirements
A B
Full
...
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: F879 − 15 (Reapproved 2020) F879 − 23
Standard Specification for
Stainless Steel Socket Button Button, Low and Flat
1
Countersunk Head Cap Screws
This standard is issued under the fixed designation F879; 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 the chemical and mechanical requirements for stainless steel inch hexagon socket button (SBHCS)
and (SBHCS), flat countersunk (SFHCS) head cap screws with nominal thread 0.060 through 0.625 in. and low head (SLHCS)
cap screws with nominal thread 0.112 through 0.625 in. intended for use in applications requiring general corrosion resistance.
1.2 Two groups of austenitic stainless steel alloys and three conditions are covered. See Table 1 and Table 2.
1.3 Units—The values stated in inch-pound units are to be regarded as standard. No other units of measurement are included in
this standard.
1.4 The following precautionary caveat pertains only to the test method portion, Section 12, of this specification: 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.
1.5 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
2.1 ASTM Standards:
A262 Practices for Detecting Susceptibility to Intergranular Attack in Austenitic Stainless Steels
A342/A342M Test Methods for Permeability of Weakly Magnetic Materials
A380/A380M Practice for Cleaning, Descaling, and Passivation of Stainless Steel Parts, Equipment, and Systems
A555/A555M Specification for General Requirements for Stainless Steel Wire and Wire Rods
A751 Test Methods and Practices for Chemical Analysis of Steel Products
A967/A967M Specification for Chemical Passivation Treatments for Stainless Steel Parts
D3951 Practice for Commercial Packaging
E18 Test Methods for Rockwell Hardness of Metallic Materials
E92 Test Methods for Vickers Hardness and Knoop Hardness of Metallic Materials
E384 Test Method for Microindentation Hardness of Materials
1
This specification is under the jurisdiction of ASTM Committee F16 on Fasteners and is the direct responsibility of Subcommittee F16.04 on Nonferrous Fasteners.
Current edition approved April 1, 2020June 1, 2023. Published April 2020July 2023. Originally approved in 1986. Last previous edition approved in 20152020 as
F879F879 – 15 (2020).-15. DOI: 10.1520/F0879-15R20.10.1520/F0879-23.
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 ----------------------
F879 − 23
TABLE 1 Mechanical Property Requirements
A B
Full Size Product Tests Machined Specimen Tests Core Hardness
Alloy
C
Alloy Group
Tensile Extension Tensile Yield Elongation
Condition Vickers Rockwell
min
Strength ksi Strength ksi Strength ksi % min
All AF 85 max 0.6D 85 max 55 max 40 210 max 95 HRB max
All CW 80 min 0.4D 80 min 40 min 25 150 min 50 HRA min
All CW1 102 min 0.4D 87 min 65 min 20 220 min 59 HRA min
A
Actual full-size testing of condition CW and CW1 may result in decreased tensile strength because of the head configuration (see Table 3). For fasteners with nominal
thread diameters larger than 0.625 in., the mechanical properties shall be agreed upon between the user and manufacturer.
B
Core hardness is only required when full-size product testing cannot be accomplished.
C
D denotes nominal thread size.
TABLE 2 Chemical Requirements
Composition, % maximum except as
...
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