Carburising

Carburising is a heat treatment process used primarily in metallurgy to improve the surface properties of ferrous metals, particularly steel. The technique involves introducing carbon into the surface layer of a metal part through a controlled heating process, followed by a rapid cooling step. This process enhances the hardness, wear resistance, and fatigue strength of the material while maintaining a softer core for improved toughness.

The carburising process typically begins with the part being heated to a temperature range between 800°C and 950°C, depending on the type of steel and desired carbon concentration. The metal is then exposed to a carbon-rich environment, which can be achieved through various methods such as gas carburising (using acetylene or natural gas), liquid carburising (using cyanide or other salt baths), or solid carburising (using charcoal or other carbonaceous materials). The carbon diffuses into the surface of the metal, creating a hardened layer known as the case.

After carburising, the part is quenched in water, oil, or another quenching medium to rapidly cool the surface while allowing the core to retain its original temperature. This step solidifies the carbon-rich layer, resulting in a hardened surface that resists wear and abrasion. The core remains relatively soft and ductile, enabling the material to withstand impact and bending without fracturing.

Carburising is widely used in industries such as automotive, aerospace, and machinery manufacturing, where components require both high surface hardness and good core strength. The process can be tailored to specific applications through adjustments in temperature, carbon concentration, and quenching methods, ensuring optimal performance for the intended use.