ASTM F879 Stainless Steel Socket Button and Flat Head Cap Screws
The stainless low-head socket screws: button and flat countersunk heads in 304 or 316, annealed at 85 ksi maximum or cold worked to 80 and 102 ksi minimum, passivated.
What F879 is.
ASTM F879 covers socket button head and socket flat countersunk head cap screws in austenitic stainless steel, Alloy Group 1 (304, 304L, 305, 384, 18-9LW, 302HQ) and 316/316L. Conditions are AF annealed, CW cold worked to 80 ksi and CW1 cold worked to 102 ksi in the smaller sizes. The screws are passivated and dimensioned to ASME B18.3.
We machine F879 button and flat head screws in special lengths and threads from certified 304 and 316 bar, passivated.
Chemical composition.
| Element | 304 | 316 | — |
|---|---|---|---|
| Carbon, max | 0.08 | 0.08 | |
| 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 | — | 2.00–3.0 |
Values per ASTM F879-02a Table 2 (verified against the specification). Confirm the edition called out on your purchase order with our estimating team.
Mechanical properties.
| Condition | Tensile strength, full size (ksi) | Yield strength, machined specimen (ksi) | Elongation, min (%) | Core hardness | — |
|---|---|---|---|---|---|
| AF (annealed) | 85 max | 55 max | 40 | 95 HRB max | |
| CW (cold worked) | 80 min | 40 min | 25 | 50 HRA min | |
| CW1 (cold worked) | 102 min | 65 min | 20 | 59 HRA min |
Values per ASTM F879-02a Table 1 (verified against the specification). Confirm the edition called out on your purchase order with our estimating team. Sizes over ⅝ in. are by agreement.
Specifications that apply.
How F879 ships from Houston.
- Hex and heavy hex bolts and cap screws
- Studs and threaded rod
- Nuts and washers to match
- Machined specials to drawing
F879 fasteners we make.
Every item is manufactured to your drawing or standard in F879, imperial or metric, with an EN 10204 3.1 certificate.
Testing, certification and marking
- Tensile and hardness per lot
- Manufacturer's identification on the head where size allows
- Certificate of conformance or test report with heat number
- Intergranular corrosion capability per ASTM A262
ASTM F835 Alloy Steel Socket Button and Flat Head Cap Screws
The low-head socket screws: button and flat countersunk heads in alloy steel at 144 ksi (½ in. and smaller) and 136 ksi above, 37 to 44 HRC — rated below A574 because the shallow head, not the shank, limits the load.
ASTM F837-20 · ASME B18.3ASTM F837 Stainless Steel Socket Head Cap Screws
The stainless socket head cap screw specification: 304-group and 316-group alloys annealed or cold worked, or 410 hardened and tempered to 180 ksi, passivated and dimensioned to ASME B18.3 — the corrosion-resistant counterpart of A574.
ASTM A276 bar · ASTM F593 bolts304 Stainless Steel (UNS S30400)
The general-purpose 18-8 stainless: 75 ksi annealed bar, cold-worked bolts to 160 ksi, non-magnetic, and resistant to water, food and most mild chemicals.