ASTM F879 - 12

    Standard Specification for Stainless Steel Socket Button and Flat Countersunk Head Cap Screws

    Active Standard ASTM F879 | Developed by Subcommittee: F16.04

    Book of Standards Volume: 01.08


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    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.

    This abstract is a brief summary of the referenced standard. It is informational only and not an official part of the standard; the full text of the standard itself must be referred to for its use and application. ASTM does not give any warranty express or implied or make any representation that the contents of this abstract are accurate, complete or up to date.

    1. Scope

    1.1 This specification covers the chemical and mechanical requirements for stainless steel inch hexagon socket button (SBHCS) and flat countersunk (SFHCS) head cap screws with nominal thread 0.060 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.

    TABLE 1 Mechanical Property Requirements

    Alloy Group

    Alloy
    Condition

    Full Size Product TestsA

    Machined Specimen Tests

    Core HardnessB

    Tensile
    Strength ksi

    ExtensionC
    min

    Tensile
    Strength ksi

    Yield
    Strength ksi

    Elongation
    % min

    Vickers

    Rockwell

    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.
    CD denotes nominal thread size.
    TABLE 2 Chemical Requirements

    Alloy Group

    UNS Designation

    Alloy

    Composition, % maximum except as shown

    Carbon

    Manganese

    Phosphorus

    Sulfur

    Silicon

    Chromium

    Nickel

    Copper

    Molybdeneunm

    Austenitic Alloys

    1

    S30400

    304 

    0.08

    2.00

    0.045

    0.030

    1.00

    18.0 to 20.0

     8.0 to 10.5

    1.00

    . . .

    1

    S30403

    304L

    0.030

    2.00

    0.045

    0.030

    1.00

    18.0 to 20.0

     8.0 to 12.0

    1.00

    . . .

    1

    S30500

    305 

    0.12

    2.00

    0.045

    0.030

    1.00

    17.0 to 19.0

    10.5 to 13.0

    1.00

    . . .

    1

    S38400

    384 

    0.08

    2.00

    0.045

    0.030

    1.00

    15.0 to 17.0

    17.0 to 19.0

    . . .

    . . .

    1

    S30430

    18–9LW 

    0.10

    2.00

    0.045

    0.030

    1.00

    17.0 to 19.0

     8.0 to 10.0

    3.0 to 4.0

    . . .

    1

    S30433

    302HQ

    0.03

    2.00

    0.045

    0.030

    1.00

    17.0 to 19.0

     8.0 to 10.0

    3.0 to 4.0

    . . .

    2

    S31600

    316 

    0.08

    2.00

    0.045

    0.030

    1.00

    16.0 to 18.0

    10.0 to 14.0

    . . .

    2.00 to 3.0

    2

    S31603

    316L

    0.03

    2.00

    0.045

    0.030

    1.00

    16.0 to 18.0

    10.0 to 14.0

    . . .

    2.00 to 3.0


    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 and health practices and determine the applicability of regulatory limitations prior to use.


    2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.

    ASTM Standards

    A262 Practices for Detecting Susceptibility to Intergranular Attack in Austenitic Stainless Steels

    A342/A342M Test Methods for Permeability of Feebly Magnetic Materials

    A380 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, Practices, and Terminology for Chemical Analysis of Steel Products

    A967 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 Method for Vickers Hardness of Metallic Materials

    E384 Test Method for Knoop and Vickers Hardness of Materials

    F593 Specification for Stainless Steel Bolts, Hex Cap Screws, and Studs

    F606 Test Methods for Determining the Mechanical Properties of Externally and Internally Threaded Fasteners, Washers, Direct Tension Indicators, and Rivets

    F788/F788M Specification for Surface Discontinuities of Bolts, Screws, and Studs, Inch and Metric Series

    F1470 Practice for Fastener Sampling for Specified Mechanical Properties and Performance Inspection

    ASME Standard

    B18.3 Socket Cap, Shoulder and Set Screws (Inch Series) Available from Global Engineering Documents, 15 Inverness Way, East Englewood, CO 80112-5704, http://www.global.ihs.com.


    ICS Code

    ICS Number Code 21.060.10 (Bolts, screws, studs)

    UNSPSC Code

    UNSPSC Code 31161501(Cap screws)


    Referencing This Standard

    DOI: 10.1520/F0879-12

    ASTM International is a member of CrossRef.

    Citation Format

    ASTM F879-12, Standard Specification for Stainless Steel Socket Button and Flat Countersunk Head Cap Screws, ASTM International, West Conshohocken, PA, 2012, www.astm.org

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