| AISI 8640 | |
 | |
| Category | Steel |
| Class | Alloy steel |
| Type | Standard |
| Common Names | Nickel-chromium-molybdenum steel |
| Designations |
Germany: DIN 1.6546 Italy: UNI 40 NiCrMo 2 KB United Kingdom: B.S. Type 7 United States: ASTM A322 , ASTM A331 , ASTM A506 , ASTM A519 , MIL SPEC MIL-S-16974 , SAE J404 , SAE J412 , SAE J770 , UNS G86400 |
| Composition | |
| |
| Element | Weight % |
| C | 0.38-0.43 |
| Mn | 0.75-1.00 |
| P | 0.035 (max) |
| S | 0.04 (max) |
| Si | 0.15-0.30 |
| Cr | 0.40-0.60 |
| Ni | 0.40-0.70 |
| Mo | 0.15-0.25 |
| Mechanical Properties | |
| |
| Properties | Conditions | ||
| T (°C) | Treatment | ||
| Density (×1000 kg/m3) | 7.7-8.03 | 25 | |
| Poisson's Ratio | 0.27-0.30 | 25 | |
| Elastic Modulus (GPa) | 190-210 | 25 | |
| Tensile Strength (Mpa) | 1862 | 25 | oil quenched, fine grained, tempered at 205°C more |
| Yield Strength (Mpa) | 1669 | ||
| Elongation (%) | 10 | ||
| Reduction in Area (%) | 40 | ||
| Hardness (HB) | 505 | 25 | oil quenched, fine grained, tempered at 205°C more |
