ASTM F880 Stainless Steel Socket Set Screws
The stainless socket set screw specification: 303, 304, 316 and related austenitic grades in annealed or cold-worked condition, torque tested by size, passivated — for shafts and collars in corrosive and food service.
What F880 is.
ASTM F880 covers socket, square head and slotted headless set screws in austenitic stainless steel (socket set screws 0.060 to 1.000 in.): 303, 303Se, 304, 304L, 305, 384, XM1, 18-9LW, 302HQ, 316 and 316L. Two conditions are offered, AF annealed and CW cold worked, each with a minimum torsional strength by size. Hardness is 70 to 95 HRB in condition AF and 96 HRB to 33 HRC in condition CW (clause 7.2). The screws are passivated per A380 or A967, dimensioned to ASME B18.3 or B18.6.2, and must be capable of passing the A262 intergranular corrosion test.
We machine F880 set screws in special lengths, points and threads on the Swiss lathes from certified 303, 304 and 316 bar, passivated.
Chemical composition.
| Element | 304 | 316 | — |
|---|---|---|---|
| Carbon, max | 0.08 | 0.03 | |
| Manganese, max | 2.00 | 2.00 | |
| Phosphorus, max | 0.045 | 0.045 | |
| Sulfur, max | 0.030 | 0.030 | |
| Silicon, max | 1.00 | 1.00 | |
| Chromium | 18.0–20.0 | 16.0–18.0 | |
| Nickel | 8.0–10.5 | 10.0–14.0 | |
| Molybdenum | — | 2.0–3.0 | |
| Copper, max | 1.00 | — |
Values per ASTM F880-12 Table 2 (verified against the specification). Confirm the edition called out on your purchase order with our estimating team. 303, 304L, 305, 316L and the other permitted alloys are in the same table.
Mechanical properties.
| Nominal size | Test torque AF, min (in·lbf) | Test torque CW, min (in·lbf) | — | — | — |
|---|---|---|---|---|---|
| #4 (0.112 in.) | 1.6 | 3.3 | |||
| #10 (0.190 in.) | 16 | 26 | |||
| ¼ in. | 40 | 67 | |||
| ⅜ in. | 138 | 237 | |||
| ½ in. | 358 | 600 |
Values per ASTM F880-12 Table 1 (verified against the specification). Confirm the edition called out on your purchase order with our estimating team. Torque testing is not required above ½ in. unless specified.
Specifications that apply.
How F880 ships from Houston.
- Hex and heavy hex bolts and cap screws
- Studs and threaded rod
- Nuts and washers to match
- Machined specials to drawing
F880 fasteners we make.
Every item is manufactured to your drawing or standard in F880, imperial or metric, with an EN 10204 3.1 certificate.
Stainless set screws and holding power
A stainless set screw cannot be hardened, so its cup point is softer than an alloy steel one and it holds by a combination of friction and a shallower bite. F880 compensates with the cold-worked CW condition, which raises torsional strength by about two thirds, and by requiring raw material capable of passing the ASTM A262 Practice E intergranular corrosion test. For hard shafts in corrosive service, a 17-4 PH set screw or a stainless screw with a hardened insert point is the alternative.
Testing, certification and marking
- Torsional strength per lot; hardness where size allows
- Manufacturer's identification on the package
- Certificate of conformance or test report with heat number
ASTM F912 Alloy Steel Socket Set Screws
The socket set screw specification: alloy steel through hardened to 45 to 53 HRC, torque tested rather than tensile tested, with cup, flat, cone, oval and half-dog points — black oxide finished.
ASTM A582 bar · ASTM F593 bolts303 Free-Machining Stainless Steel (UNS S30300)
304 with sulfur added for fast, clean machining — the grade for complex turned fasteners and fittings where corrosion resistance can give a little.
ASTM A276 bar · ASTM F593 bolts316 Stainless Steel (UNS S31600)
The marine and chemical-plant stainless: 2 to 3 percent molybdenum for pitting and crevice resistance in chlorides, with the same strength tables as 304.