Liquid Carburising
A widely used method of case-hardening steel that eliminates scaling and the tendency to decarburisation and results in clean components. Sodium cyanide is the common media for this process, usually heated within the range of 900-930oC. It is advisable to pre-heat the components in neutral salts to avoid a temperature drop resulting from immersing cold components into the cyanide. After carburising, either single quench hardening or refining and hardening and tempering is carried out.
