Overview of 40Cr Steel: Composition, Specifications, and Uses

40Cr is a medium-carbon, low-alloy steel renowned for its excellent strength, toughness, and hardenability. Widely used in engineering and manufacturing, this steel grade is favored for components requiring durability under moderate to high stress. Its versatility, combined with cost-effectiveness, makes 40Cr a popular choice across multiple industries.

Chemical Composition

The properties of 40Cr stem from its precise chemical makeup:

Carbon (C): 0.37-0.44%, providing hardness and strength.

Silicon (Si): 0.17-0.37%, enhancing elasticity.

Manganese (Mn): 0.50-0.80%, improving toughness and wear resistance.

Chromium (Cr): 0.80-1.10%, boosting hardenability and corrosion resistance.

Phosphorus (P): ≤0.035%, minimized to prevent brittleness.

Sulfur (S): ≤0.035%, kept low for better ductility.

This composition allows 40Cr to achieve a good balance of mechanical properties, especially after heat treatment, making it suitable for demanding applications.

Dimensions and Specifications

40Cr is available in various forms, including bars, plates, and pipes. Steel plates typically range from 2 mm to 120 mm in thickness, 1000 mm to 2500 mm in width, and 2000 mm to 12,000 mm in length. Round bars are produced with diameters from 10 mm to 400 mm, while seamless pipes offer outer diameters of 6 mm to 530 mm, with customizable wall thicknesses. These dimensions support its use in both small and large-scale components.

Delivery Condition

40Cr is generally supplied in a normalized or quenched-and-tempered state. Normalization at 850-880°C refines the grain structure, while quenching at 840-860°C followed by tempering at 500-650°C enhances hardness (typically 229-269 HB) and toughness. This treatment ensures optimal performance for machined parts.

Application Range

40Cr excels in applications requiring strength and wear resistance. It is commonly used in the automotive industry for gears, shafts, and axles, and in machinery for spindles, bolts, and couplings. Additionally, it serves in construction equipment and tools, benefiting from its ability to withstand dynamic loads after heat treatment.

In summary, 40Cr is a reliable steel grade, valued for its robust composition, flexible sizing, and broad industrial applications.