ASTM F880 Stainless Steel Socket Set Screws
ASTM F880 is a standard specification for austenitic stainless steel set screws, covering socket set screws, square head set screws, and slotted headless set screws. These fasteners are used to secure components in position, with different head and drive configurations available for different installation requirements. The standard defines requirements related to material composition, mechanical performance, and testing to help ensure that the fasteners meet the specified technical criteria.
When selecting ASTM F880 socket set screws, the stainless steel grade, dimensional specifications, thread size, and material condition are important considerations. The standard specifies two material conditions: AF (solution annealed) and CW (cold worked). Socket strength, torque resistance, and corrosion resistance are also relevant when evaluating product performance. Selecting the appropriate specifications helps ensure that the screws meet the requirements of the intended assembly and operating environment.
Product Type:
ASME B18.3 specifies the dimensional requirements for inch-series socket set screws, including different point styles and nominal screw sizes. Key dimensions include thread diameter, thread pitch, overall length, hex socket dimensions, and point geometry. These specifications help ensure dimensional consistency and compatibility with mating components.
ASTM F880 socket set screws can be specified according to the dimensional requirements of ASME B18.3, with product selection based on nominal size, thread series, length, and point style. Common configurations include cup point, flat point, cone point, oval point, and half dog point set screws, each offering different contact characteristics for specific assembly requirements.
Material Chemical Composition:
ASTM F880 specifies the chemical composition requirements for austenitic stainless steel set screws. The permitted composition depends on the stainless steel alloy grade, with limits established for elements such as carbon, chromium, nickel, and molybdenum, where applicable. These elements influence the material’s corrosion resistance, mechanical characteristics, and suitability for different service environments.
The chemical composition of the steel must comply with the requirements specified for the applicable alloy grade. When selecting ASTM F880 stainless steel socket set screws, the alloy designation and chemical composition should be considered alongside the required material condition and mechanical properties. The table below presents the chemical composition limits for the applicable stainless steel grades.
| UNS Designation | Alloy | Carbon | Manganese | Phosphorus | Sulfur | Silicon | Chromium | Nickel | Copper | Molybdenum |
|---|---|---|---|---|---|---|---|---|---|---|
| S30300 | 303ᴬ | 0.15 | 2.00 | 0.20 | 0.15 min | 1.00 | 17.0 - 19.0 | 8.0 - 10.0 | -- | 0.60 maxᴬ |
| S30323 | 303se | 0.15 | 2.00 | 0.20 | 0.06 | 1.00 | 17.0 - 19.0 | 8.0 - 10.0 | -- | Se 0.15 min |
| S30400 | 304.00 | 0.08 | 2.00 | 0.05 | 0.03 | 1.00 | 18.0 - 20.0 | 8.0 - 10.5 | 1.00 | -- |
| A30403 | 304L | 0.03 | 2.00 | 0.05 | 0.03 | 1.00 | 18.0 - 20.0 | 8.0 - 12.0 | 1.00 | -- |
| S30500 | 305.00 | 0.12 | 2.00 | 0.05 | 0.03 | 1.00 | 17.0 - 19.0 | 10.5 - 13.0 | 1.00 | -- |
| S38400 | 384.00 | 0.08 | 2.00 | 0.05 | 0.03 | 1.00 | 15.0 - 17.0 | 17.0 - 19.0 | -- | -- |
| S20300 | XM1ᴬ | 0.08 | 5.00 to 6.50 | 0.40 | 0.18 to 0.35 | 1.00 | 16.0 - 18.0 | 5.0 - 6.5 | 1.75 - 2.25 | 0.50 maxᴬ |
| S30430 | 18-9LW | 0.10 | 2.00 | 0.05 | 0.03 | 1.00 | 17.0 - 19.0 | 8.0 - 10.0 | 3.0 - 4.0 | -- |
| S30433 | 302HQ | 0.03 | 2.00 | 0.05 | 0.03 | 1.00 | 17.0 - 19.0 | 8.0 - 10.0 | 3.0 - 4.0 | -- |
| S31600 | 316.00 | 0.08 | 2.00 | 0.05 | 0.03 | 1.00 | 16.0 - 18.0 | 10.0 - 14.0 | -- | 2.0 - 3.0 |
| S31603 | 316 L | 0.03 | 2.00 | 0.05 | 0.03 | 1.00 | 16.0 - 18.0 | 10.0 - 14.0 | -- | 2.0 - 3.0 |
Torsional Strength Requirements:
ASTM F880 specifies minimum torque requirements for stainless steel socket set screws to verify their resistance to torsional loading during installation. The screws must withstand the specified test torque without socket reaming or screw bursting. The required torque values depend on the nominal screw size and material condition. The table below summarizes the minimum test torque requirements for applicable screw sizes.
| Nominal Screw Size | Cup and Flat Points, mm | Cone and Oval Points | Half Dog Points, mm | Test Torque, in-lb, min AF | Test Torque, in-lb, min CW | |
| 0.00 | 0.06 | 0.11 | 0.13 | 0.11 | 0.30 | 0.60 |
| 1.00 | 0.07 | 0.13 | 0.14 | 0.13 | 0.70 | 1.20 |
| 2.00 | 0.09 | 0.13 | 0.14 | 0.14 | 0.70 | 1.20 |
| 3.00 | 0.10 | 0.14 | 0.16 | 0.16 | 1.60 | 3.30 |
| 4.00 | 0.11 | 0.14 | 0.17 | 0.16 | 1.60 | 3.30 |
| 5.00 | 0.13 | 0.19 | 0.19 | 0.17 | 3.00 | 5.00 |
| 6.00 | 0.14 | 0.17 | 0.20 | 0.19 | 3.00 | 5.00 |
| 8.00 | 0.16 | 0.19 | 0.22 | 0.20 | 9.00 | 16.00 |
| 10.00 | 0.19 | 0.19 | 0.25 | 0.23 | 16.00 | 26.00 |
| 1/4" | 0.25 | 0.25 | 0.31 | 0.30 | 40.00 | 67.00 |
| 5/16" | 0.31 | 0.31 | 0.39 | 0.36 | 79.00 | 135.00 |
| 3/8" | 0.38 | 0.38 | 0.44 | 0.44 | 135.00 | 237.00 |
| 7/16" | 0.44 | 0.44 | 0.55 | 0.48 | 220.00 | 378.00 |
| 1/2" | 0.50 | 0.50 | 0.61 | 0.55 | 358.00 | 600.00 |