Quenched & Tempered Alloy Steel Socket Set Screws
ASTM F912 specification covers the requirements for quenched and tempered alloy steel socket-set screws (SSS) in nominal diameters #0 through 2 inch in imperial and M1.6 to M48 in metric series having hardnesses 45 to 53 HRC. These set screws are intended for compression applications only and are not customarily subjected to embrittlement tests. The screws shall be fabricated from alloy steel made to fine grain practice. In the event of controversy over grain size, referee tests on finished screws conducted in accordance with Test Methods E112 shall prevail. The screws may be forged, formed, extruded, machined, or ground to meet the dimensional characteristics and performance requirements. Set screws shall be heat treated by quenching in oil from above the transformation temperature and then tempered by reheating to meet the hardness range. Unless otherwise specified, the screws shall be furnished with one of the following standard surfaces as manufactured, at the option of the manufacturer; (1) bright uncoated; (2) thermal black oxide; or (3) chemical black oxide. Hydrogen embrittlement tests shall not be required for screws furnished in these conditions.
| Element | Composition, % | |
|---|---|---|
| Heat Analysis | Product Analysis | |
| C | 0.30 to 0.48 | 0.28 to 0.50 |
| P, max | 0.035 | 0.040 |
| S, max | 0.040 | 0.045 |
| Nominal Size | Shortest Nominal Screw Lengths Subject to Torque Testing for | Test Torque | |||
|---|---|---|---|---|---|
| Cup and Flat Points | Cone and Oval Points | Half Dog Points | in.-lb, min | ||
| 0 | 0.060 | 0.109 | 0.125 | 0.109 | 1.1 |
| 1 | 0.073 | 0.125 | 0.141 | 0.125 | 2.1 |
| 2 | 0.086 | 0.125 | 0.141 | 0.141 | 2.1 |
| 3 | 0.099 | 0.141 | 0.156 | 0.156 | 6.0 |
| 4 | 0.112 | 0.141 | 0.172 | 0.156 | 6.0 |
| 5 | 0.125 | 0.156 | 0.188 | 0.172 | 11 |
| 6 | 0.138 | 0.172 | 0.203 | 0.188 | 11 |
| 8 | 0.164 | 0.188 | 0.219 | 0.203 | 23 |
| 10 | 0.190 | 0.188 | 0.250 | 0.234 | 40 |
| 1/4 | 0.250 | 0.250 | 0.312 | 0.297 | 94 |
| 5/16 | 0.312 | 0.312 | 0.391 | 0.359 | 183 |
| 3/8 | 0.375 | 0.375 | 0.438 | 0.438 | 317 |
| 7/16 | 0.437 | 0.438 | 0.547 | 0.484 | 502 |
| 1/2 | 0.500 | 0.500 | 0.609 | 0.547 | 750 |
| 5/8 | 0.625 | 0.625 | 0.766 | 0.672 | 1460 |
| 3/4 | 0.750 | 0.750 | 0.906 | 0.797 | 2520 |
| 7/8 | 0.875 | 0.875 | 1.125 | 0.984 | 5750 |
| 1 | 1.000 | 1.000 | 1.266 | 1.125 | 8000 |
| 11/8 | 1.125 | 1.125 | 1.391 | 1.188 | 8000 |
| 11/4 | 1.250 | 1.250 | 1.500 | 1.312 | 11 000 |
| 13/8 | 1.375 | 1.375 | 1.656 | 1.438 | 11 000 |
| 11/2 | 1.500 | 1.500 | 1.797 | 1.562 | 18 100 |
| 13/4 | 1.750 | 1.750 | 2.219 | 1.953 | 38 000 |
| 2 | 2.000 | 2.000 | 2.391 | 2.078 | 38 000 |
Product Shall be Marked with our manufacturing trade mark "TorqBolt" or "TB" along with the
designated Grade.
Grade and manufacturer’s identification symbols shall be applied to one end of studs and to the heads of
bolts and screws of all sizes. (If the available area is inadequate, the grade symbol may be marked on
one end and the manufacturer’s identification symbol marked on the other end.) For bolts and screws
smaller than 1⁄4 in. [6 mm] in diameter and studs smaller than 3⁄8 in. [10 mm] in diameter and for 1⁄4
in. [6 mm] in diameter studs requiring more than a total of three symbols, the marking shall be a matter
of agreement between the purchaser and the manufacturer.
B18.3
Hexagon Socket Head Cap Screws
B18.3
Hexagon Socket Head Shoulder Screws
B18.3
Hexagon Socket Flat Countersunk Head Cap Screws
B18.3
Spline Socket Head Cap Screws
B18.3
Hexagon And Spline Socket Head Cap Screws
B18.3
Hexagon Socket And Spline Socket Button Head Cap Screws
B18.3
Hexagon And Spline Socket Flat Countersunk Head Cap Screws
B18.3
Hexagon And Spline Socket Set Screws
B18.3
Hexagon And Spline Socket Set Screw Optional Cup Points
A751 Test Methods, Practices, and Terminology for Chemical Analysis of Steel
Products
E3 Guide for Preparation of Metallographic Specimens
E112 Test Methods for Determining Average Grain Size
E384 Test Method for Microindentation Hardness of Materials
F606/F606M Test Methods for Determining the Mechanical Properties of Externally and
Internally Threaded Fasteners, Washers, Direct Tension Indicators, and Rivets
F2328 Test Method for Determining Decarburization and Carburization in Hardened and
Tempered Threaded Steel Bolts, Screws, Studs, and Nuts