We manufacture forging ingots, billets, and blooms in alloy steel specifically for SAE 4140, designed for high-strength and heavy-duty engineering applications.
SAE 4140 is a medium carbon chromium-molybdenum alloy steel renowned for its exceptional strength, high toughness, and excellent fatigue resistance. It is engineered to withstand high mechanical loads, shock, and repeated stress, making it an ideal choice for automotive, heavy machinery, oil & gas, and critical engineering components.
The addition of chromium enhances hardenability and wear resistance, while molybdenum improves toughness, tempering resistance, and high-temperature performance. SAE 4140 also offers good machinability in the annealed condition and maintains dimensional stability after heat treatment, making it highly suitable for forging and precision machining applications.
This grade provides an excellent balance of performance, durability, and cost-effectiveness for demanding industrial uses.
| Element | Content (%) | Function / effect |
| Carbon (c) | 0.38 – 0.43 | Provides hardness and tensile strength |
| Manganese (mn) | 0.75 – 1.00 | Improves hardenability and toughness |
| Silicon (si) | 0.15 – 0.35 | Increases strength and elasticity |
| Chromium (cr) | 0.80 – 1.10 | Enhances hardness, wear resistance, and depth of hardening |
| Molybdenum (mo) | 0.15 – 0.25 | Improves toughness, fatigue resistance, and tempering stability |
| Phosphorus (p) | Max 0.035 | Impurity; lower content improves toughness |
| Sulphur (s) | Max 0.040 | Impurity; controlled for better machinability |
(properties may vary depending on section size and heat treatment conditions)
The heat treatment process can be optimized to achieve the desired balance of strength and toughness based on specific application requirements.
SAE 4140 has several international equivalents, including:
SAE 4140 offers a superior combination of high strength, toughness, and fatigue resistance. Its excellent hardenability and stable response to heat treatment make it ideal for components subjected to heavy loads and cyclic stress. Additionally, its good machinability and dimensional stability help reduce manufacturing costs and improve final product quality.
| Grade | Carbon (%) | Key applications | Heat treatment | Comments |
| SAE 4140 | 0.38 – 0.43 | Shafts, gears, crankshafts | Quenching & tempering | High strength and fatigue resistance |
| 42CrM04 | 0.38 – 0.45 | Automotive and heavy machinery parts | Quenching & tempering | European equivalent |
| En19 | 0.35 – 0.45 | General engineering components | Quenching & tempering | Widely used british equivalent |
SAE 4140 is a high-performance chromium-molybdenum alloy steel optimized for quench and temper applications in automotive and engineering industries. It delivers reliable performance, long service life, and excellent value for a wide range of high-stress components.