4140 | 1.7225 | SCM440 | 42CrMo
4140 (1.7225 / 42CrMo4) is a chromium-molybdenum alloy steel offering high strength, good toughness, and excellent hardenability. It provides a good balance of wear resistance, fatigue strength, and machinability, making it suitable for demanding mechanical components and engineering applications.
Available Form
Round Bar
Custom Diameter & Length
Flat Bar
Custom Thickness, Width & Length
Square Bar
Custom Width & Length
Steel Plate
Custom Thickness, Width & Length
Steel Grade Comparison
| W-Nr | EN | AISI | JIS |
| 1.7225 | 42CrMo4 | 4140 | SCM440 |
Chemical Composition(wt%)
| C | Si | Mn | P | S | Cr | Mo |
| 0.35~0.45 | 0.20~0.80 | 0.70~1.00 | ≤0.04 | ≤0.045 | 0.80~1.10 | 0.15~0.25 |
Physical Properties
Density：7.85 g/cm³
Modulus of Elasticity: 205 GPa
Thermal Conductivity: 42.6 W/(m.K)
| Temperature | 20-100°C | 2-200°C | 2-300°C | 2-400°C |
| Coefficient of Thermal Expansion (×10-6 /K) | 11.1 | 12.1 | 12.9 | 13.5 |
Heat Treatment Process
Hardening: Heat the steel evenly to 840~880°C until the whole section reaches temperature. Then quench in oil to cool.
Annealing: Heat the steel to 840~860°C, hold it well at temperature, and then let it cool slowly inside the furnace.
Tempering: Heat the steel uniformly, hold it at the selected tempering temperature, and then allow it to cool in still air. Tempering temperature: 400~650°C (depending on required hardness).
Application Fields
Suitable for medium and high-stress components in automotive and mechanical engineering: shafts, connecting rods, crankshafts, bolts, etc.
Disclaimer: the information and data presented herein are typical values for reference and are not intended as warranties to readers.
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