1. Case Hardening is the process of making the outer part of a component to be hard while leaving the inner part soft.
2. Tempering: This is the process of making or reducing the hardness of a component to a tolerance or the require hardness.
3. Normalizing: This is the process of making or refining the internal structure of a distorted grain structure of any component i.e bringing a material back to its original structure after deformation by force.