Standard specification for carbon and alloy steel nuts.
Scope – This specification covers the chemical and mechanical requirements for carbon and alloy steel nuts used on bolts, studs, and externally threaded fasteners.
Recommended Mating Materials- See ASTM A307, A325, A354, A449, A490
Grades |
A | Carbon steel |
| B | Carbon steel | |
| C | Carbon steel, quenched and tempered | |
| D | Carbon steel, quenched and tempered | |
| DH | Carbon steel, quenched and tempered | |
| C3 | Weathering steel, quenched and tempered | |
| DH3 | Weathering steel, quenched and tempered |
Chemical
|
Element | Grades O, A, B, C | D | DH | |||||
| Carbon | 0.55 max | 0.55 max | 0.20 – 0.55 | ||||||
| Manganese | 0.30 min | 0.60 min | |||||||
| Phosphorus | 0.12 max | 0.04 max | 0.04 max | ||||||
| Sulfur | 0.15 max* | 0.05 max | 0.05 max | ||||||
| Classes for Grade C3* | DH3 | ||||||||
| A | B | C | D | E | F | N | |||
| Carbon | 0.33 – 0.40 | 0.38 – 0.48 | 0.15 – 0.25 | 0.15 – 0.25 | 0.20 – 0.25 | 0.20 – 0.25 | 0.20 – 0.53 | ||
| Manganese | 0.90 – 1.20 | 0.70 – 0.90 | 0.80 – 1.35 | 0.40 – 1.20 | 0.60 – 1.00 | 0.90 – 1.20 | 0.40 min | ||
| Phosphorus | 0.040 max | 0.06 – 0.12 | 0.035 max | 0.040 max | 0.040 max | 0.040 max | 0.07 – 0.15 | 0.046 max | |
| Sulfur | 0.050 max | 0.050 max | 0.040 max | 0.050 max | 0.040 max | 0.040 max | 0.050 max | 0.050 max | |
| Silicon | 0.15 – 0.35 | 0.30 – 0.50 | 0.15 – 0.35 | 0.25 – 0.50 | 0.15 – 0.35 | 0.15 – 0.35 | 0.20 – 0.90 | ||
| Copper | 0.25 – 0.45 | 0.20 – 0.40 | 0.20 – 0.50 | 0.30 – 0.50 | 0.30 – 0.60 | 0.20 – 0.40 | 0.25 – 0.55 | 0.20 min | |
| Nickel | 0.25 – 0.45 | 0.50 – 0.80 | 0.25 – 0.50 | 0.50 – 0.80 | 0.30 – 0.60 | 0.20 – 0.40 | 1.00 max | 0.20 min** | |
| Chromium | 0.45 – 0.65 | 0.50 – 0.75 | 0.30 – 0.50 | 0.50 – 1.00 | 0.60 – 0.90 | 0.45 – 0.65 | 0.30 – 1.25 | 0.45 min | |
| Vanadium | 0.020 min | ||||||||
| Molybdenum | 0.06 max | 0.10 max | 0.15 min** | ||||||
| Titanium | 0.05 max | ||||||||
| *Selection of a class shall be at the option of the manufacturer. **Nickel or Molybdenum may be used. | |||||||||
Mechanical
|
Grade | Material Markings | Style | Size, in. | Proof Load, ksi | Hardness, HBN | |
| Black | Galv. | ||||||
| A |  |
Hex | 1/4 – 1-1/2 | 90 | 68 | 116 – 302 | |
| Heavy Hex | 1/4 – 4 | 100 | 75 | 116 – 302 | |||
| B | Heavy Hex | 1/4 – 1 | 133 | 100 | 121 – 302 | ||
| Heavy Hex | 1-1/8 – 1-1/2 | 116 | 87 | 121 – 302 | |||
| C |  |
Heavy Hex | 1/4 – 4 | 144 | 144 | 143 – 352 | |
| C3 |  |
||||||
| D | D | Heavy Hex | 1/4 – 4 | 150 | 150 | 248 – 352 | |
| DH | DH | Heavy Hex | 1/4 – 4 | 175 | 150 | 248 – 352 | |
| DH3 | DH3 | ||||||