Alloy Steel

Alloy steel grades are selected when a hard, wear-resistant surface is required, along with superior mechanical properties after heat treatment. These steels contain a combination of alloying elements that enhance their strength, toughness, and resistance to impact and fatigue. The choice of steel depends on factors such as the ruling section, required hardness, tensile strength, and intended application.

Typical Applications

Alloy steels are widely used in applications that demand high strength, durability, and resistance to wear and fatigue. Some of the most common applications include:

• Gears – Used in automotive, aerospace, and industrial machinery where high torque and durability are essential.
• Cams & Rollers – Components that experience repetitive motion and require both toughness and wear resistance.
• Transmission Components – Drive shafts, axles, and couplings that must endure high loads and torque.
• Highly Stressed Machine Parts – Parts subjected to dynamic and impact loading, such as bolts, crankshafts, and connecting rods.

To enhance surface hardness and wear resistance, many alloy steels are suitable for induction hardening, making them ideal for applications requiring extreme durability.

Common Specifications

Alloy steels are available under various national and international standards, ensuring quality and performance across different industries. Some common specifications include:

• British Standard (BS 970): 605M36, 708M40, 817M40
• European Standard (EN 10083-1): 41Cr4, 42CrMo4, 34CrNiMo6
• American Standard (AISI): 4140, 4340

Properties & Heat Treatment

Alloy steels typically contain two or more alloying elements, such as nickel, molybdenum, chromium, vanadium, and manganese, which contribute to their strength, hardness, and wear resistance. These steels are supplied in a softened condition, making them easier to machine.

Once machining is complete, components can be hardened and tempered to achieve the desired mechanical properties. Alternatively, some grades are available in a final heat-treated condition, meaning they can be put directly into service without further processing.

Direct hardening alloy steels are particularly beneficial in applications requiring exceptional strength, high fatigue resistance, and impact toughness, ensuring long-lasting performance under demanding conditions.