Commonly used heat treatment methods
The heat treatment of steel is divided into three categories.
Integral heat treatment (including annealing, normalizing, quenching, quenching + tempering, tempering and others).
Surface heat treatment (including surface quenching and tempering, etc.)
chemical heat treatment (including carburizing, nitriding, carburizing, carburizing, carburizing, carburizing, other non-metals, carburizing, polycarburizing, carburizing).
All heat treatment consists of three stages: heat preservation and cooling. 
