Carburising, also referred to as Case or Cyanide Hardening, is a heat treatment process that produces a surface which is resistant to wear and tear, while maintaining the durability and strength of the core. This treatment is applied to low carbon steel and iron parts after machining, as well as high alloy steel gears, bearings, and other components.
An object usually undergoes the case hardening process once it has been formed into its final shape, but the process can also be used to enhance the hardening element of bars to be used in pattern welding and similar processes.