Specifications ASTM A194
ASTM A194 covers nuts made from carbon steel, stainless steel or alloy, most commonly 2H, 2HM, 3, 4, 6, 7, 7M, 8, 8M, 8T, 16,.. .,used by ASTM A193 bolt for high pressure and high temperature. Size ranges from 1/4 to 4 inches or from M6 to M100.
Grade
| Grade | Crafting materials |
|---|---|
| 2 | Carbon steel |
| 2H | Carbon steel is heat treated and tempered |
| 2HM | Carbon steel is heat treated and tempered, hardness tested |
| 3 | Stainless Steel 501 |
| 4 | Carbon Steel – Molybdenum is heat treated and tempered |
| 6 | Stainless steel 401 |
| 7 | Chromium Molybdenum Steel (4140,4142, 4145, 4140H, 4142H, 4145H) heat treated and tempered |
| 7M | Chromium Molybdenum Steel (4140,4142, 4145, 4140H, 4142H, 4145H) is heat treated and tempered, tested for hardness |
| 7L | Chromium Molybdenum Steel (4140,4142, 4145, 4140H, 4142H, 4145H) heat treated and tempered, impact tested |
| 8 | Stainless Steel 304 |
| 8M | Stainless Steel 316 |
| 8T | Stainless Steel 321 |
| 16 | Heat-treated and tempered chromium-molybdenum-vanadium alloy steel |
Chemical composition
| Ingredient | Grade | ||||||||
|---|---|---|---|---|---|---|---|---|---|
| 2H, 2HM | 3 | 4 | 6 | 7, 7M | 8 | 8M | 8T | 16 | |
| Carbon | Min 0.40 | Min 0.10 | 0.4 – 0.5 | 0.15 | 0,37 – 0.49 | 0.08 | 0.08 | 0.08 | 0.36 – 0.47 |
| Mangan | 1 | 1 | 0.7 – 0.9 | 1 | 0.65 – 1.1 | 2 | 2 | 2 | 0.45 – 0.7 |
| Phosphorus | 0.04 | 0.04 | 0.035 | 0.04 | 0.035 | 0.045 | 0.045 | 0.045 | 0.035 |
| Sulfur | 0.05 | 0.03 | 0.04 | 0.03 | 0.04 | 0.03 | 0.03 | 0.03 | 0.04 |
| Silicon | 0.4 | 1 | 0.15 – 0.35 | 1 | 0.15 – 0.35 | 1 | 1 | 1 | 0.15 – 0.35 |
| Chromium | – | 4 – 6 | – | 11.5 – 13.5 | 0.75 – 1.2 | 18 – 20 | 16 – 18 | 17 – 19 | 0.8 – 1.15 |
| Niken | – | – | – | – | – | 8 – 11 | 10 – 14 | 9 – 12 | – |
| Molypden | – | 0.4 – 0.65 | 0.2 – 0.3 | – | 0.15 – 0.25 | – | 2 – 3 | – | 0.5 – 0.65 |
| Titan | – | – | – | – | – | – | – | Min 5x(C+N) Max 0.7 |
– |
| Nitrogen | – | – | – | – | – | – | – | 0.1 | – |
| Khác | – | – | – | – | – | – | – | – | Vanadium 0.25 – 0.35 Aluminum Max 0.015 |
Hardness
| Grade | Brinell hardness | Hardness | ||
|---|---|---|---|---|
| HRC | HRB | |||
| 2H | Less than1½ inch or M36 | 248 – 327 | 24 – 35 | – |
| Over 1½ inch or M36 | 212 – 327 | Max 35 | Min 95 | |
| 2HM And 7M | 159 – 235 | – | 84 – 99 | |
| 3, 4, 7, 16 | 248 – 327 | 24 – 35 | – | |
| 6 | 225 – 271 | 20 – 28 | – | |
| 8, 8C, 8M, 8F, 8MCuN | 126 – 300 | Max 32 | Min 60 | |
