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 |
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
B 18.3 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.
Keywords
corrosion resistant; stainless steel; socket button head cap screws; socket flat countersunk head cap screws;
ICS Code
ICS Number Code 21.060.10 (Bolts, screws, studs)
DOI: 10.1520/F0879-12
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