| AISI 8740 | |
 | |
| 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: AMS 6322 , AMS 6322F , AMS 6323 , AMS 6323D , AMS 6325 , AMS 6325D , AMS 6327 , AMS 6327D , AMS 6358 , AMS 6358B , ASTM A322 , ASTM A331 , ASTM A505 , ASTM A519 , MIL SPEC MIL-S-6049 , SAE J404 , SAE J412 , SAE J770 , UNS G87400 |
| 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 | 0.20-0.30 |
| 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) | 695.0 | 25 | annealed at 815°C more |
| Yield Strength (Mpa) | 415.8 | ||
| Elongation (%) | 22.2 | ||
| Reduction in Area (%) | 46.4 | ||
| Hardness (HB) | 201 | 25 | annealed at 815°C more |
| Impact Strength (J) (Izod) |
40 | 25 | annealed at 815°C more |
