| AISI 4042 | |
 | |
| Category | Steel |
| Class | Alloy steel |
| Type | Standard |
| Common Names | Molybdenum steel |
| Designations | United States: ASTM A322 , ASTM A331 , ASTM A519 , SAE J404 , SAE J412 , SAE J770 , UNS G40420 |
| Composition | |
| |
| 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) | 1800 | 25 | oil quenched, fine grained, tempered at 205°C more |
| Yield Strength (Mpa) | 1662 | ||
| Elongation (%) | 12 | ||
| Reduction in Area (%) | 37 | ||
| Hardness (HB) | 516 | 25 | oil quenched, fine grained, tempered at 205°C more |
