Case-hardening steels

Case-hardening steels are special types of steel that have been developed for case-hardening, in particular for carbonization (carburization). This heat treatment method increases the hardness and wear resistance of the surface, while the core of the component remains tough and ductile to withstand impact loads.

Carbonizing increases the carbon content in the layers near the surface of the steel by diffusion. This is achieved by heating the workpiece in a carbon-rich atmosphere, such as is generated in gaseous, solid or liquid media. The temperature is typically between 850 and 950 degrees Celsius. The carbon diffuses into the steel and forms a carbon-rich surface layer, while the core retains its original carbon content.

After carburizing, the workpiece is often quenched to harden the surface layer. This surface layer contains martensite, which is formed by rapid cooling, resulting in high hardness and wear resistance. The core remains tough and elastic due to the lower carbon content, giving the component an ideal combination of surface hardness and core toughness.

Case-hardening steels such as 16MnCr5 or 20MoCr4 are typical examples of materials that are optimized for this process. They are frequently used in the automotive industry, in mechanical engineering and in gear components where high load-bearing capacity and wear resistance are required. Carburizing makes it possible to significantly extend the service life of components and increase their performance in demanding applications.