B8 Cl.2Stud bolt
ASTM A193 Grade B8 Class 2
The same 304 as Class 1, cold worked to roughly the strength of B7 in small diameters. Strength falls sharply as diameter grows — check the table before assuming it holds at M36.
- Base material
- Austenitic stainless steel, AISI 304
- Heat treatment condition
- Solution treated then strain hardened
- Hardness, max
- 321 HBW / 35 HRC maximum
Service temperature
-254 °C+400 °C−273+900 °C
Above roughly 400 °C the cold work relaxes and the strength advantage over Class 1 disappears. Class 2 is not available above 1½ in diameter.
Chemical composition
| Element | Min (% by weight) | Max (% by weight) |
|---|---|---|
| C | — | 0.08 |
| Mn | — | 2.00 |
| Si | — | 1.00 |
| P | — | 0.045 |
| S | — | 0.030 |
| Cr | 18.0 | 20.0 |
| Ni | 8.0 | 11.0 |
Mechanical properties
| Diameter | Tensile strength, min | Yield strength, min | Elongation, min | Reduction of area, min |
|---|---|---|---|---|
| ≤ ¾ in (≤ M20) | 860 MPa (125 ksi) | 690 MPa (100 ksi) | 12 % | 35 % |
| > ¾ – 1 in (M20–M24) | 795 MPa (115 ksi) | 550 MPa (80 ksi) | 15 % | 35 % |
| > 1 – 1¼ in (M24–M30) | 725 MPa (105 ksi) | 450 MPa (65 ksi) | 20 % | 35 % |
| > 1¼ – 1½ in (M30–M36) | 690 MPa (100 ksi) | 345 MPa (50 ksi) | 28 % | 45 % |
Matching nuts
Equivalent grades
- AISI 304 cold worked
- EN 1.4301
- ISO 3506 A2-70 (gan tuong duong)
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