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- 42CrMo4 alloy steel 1.7225 SCM440 4140 round bar carbon steel
42CrMo4 alloy steel 1.7225 SCM440 4140 round bar carbon steel
Details
42CrMo is a high-performance medium-carbon chromium-molybdenum alloy structural steel specified by Chinese standard GB/T 3077. Compared with ordinary 40Cr steel, the addition of molybdenum greatly improves its hardenability, high-temperature strength, anti-temper brittleness and fatigue resistance. It can obtain uniform and deep hardened layer after heat treatment, with excellent matching of high strength, high toughness and wear resistance. Its machining performance is satisfactory under normalized or quenched-tempered state, so it is a mainstream material for heavy-load mechanical parts all over the world.
Chemical Composition of 42CrMo (Mass Fraction)
| Element | Content Range | Main Function |
|---|---|---|
| C | 0.38–0.45% | Provides basic hardness and tensile strength |
| Si | 0.17–0.37% | Deoxidizes molten steel, raises elastic limit |
| Mn | 0.50–0.80% | Optimizes toughness and hardening performance |
| Cr | 0.90–1.20% | Enhances wear resistance and hardenability |
| Mo | 0.15–0.25% | Suppresses temper brittleness, stabilizes high-temperature performance |
| P | ≤0.035% | Harmful impurity, limited to prevent cold brittleness |
| S | ≤0.035% | Harmful impurity, controlled to avoid hot brittleness |
International Equivalent Grades of 42CrMo
| Region & Country | Standard Grade | Material No. & Standard Code |
|---|---|---|
| China | 42CrMo | GB/T 3077 |
| United States | AISI 4140 | ASTM A29 / A29M |
| European Union | 42CrMo4 | 1.7225, EN 10083-1 |
| Japan | SCM440 | JIS G4053 |
| International Standard | 42CrMo4 | ISO 683-1 |
| Russia | 38ХМ | GOST 4543 |
After quenching and high-temperature tempering, 42CrMo steel achieves tensile strength above 1080 MPa and good impact toughness. It can also adopt surface induction hardening or nitriding to get hard wear-resistant surface while maintaining tough core, which adapts to complex working conditions with alternating load, impact and friction.
Its application scope covers heavy industry sectors. In automobile manufacturing, it is used for engine crankshafts, transmission drive shafts, gear shafts, connecting rods and vehicle axle parts bearing huge alternating torque. In general machinery and machine tools, it produces heavy-duty spindles, large gears, spline shafts, hydraulic cylinder piston rods and high-strength large bolts. For engineering machinery and mining equipment, it is made into pin shafts, gearbox components, hydraulic parts and heavy load bearings. Besides, it is widely applied in wind power equipment, plastic mold holders, petroleum drilling mechanical parts and high-pressure valve bodies that require long service life under variable loads.
With superior comprehensive mechanical properties and stable heat treatment effect, 42CrMo is irreplaceable for manufacturing key heavy-load components, and its equivalent international grades facilitate cross-border procurement and global mechanical equipment production.
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