The heat treatment process of cast steel joints generally consists of three stages: heating, heat preservation and cooling.
Heat treatment methods include: annealing, normalizing, normalizing and tempering.
The mechanical properties of three methods are different, for the general shape is not too complex, the wall thickness and not too thick cast steel joints are most commonly used is normalizing. It is more suitable for the steel joints with complex shape and easy deformation and cracking to use annealing. Normalizing and tempering are used for thicker carbon steel castings and low-alloy steels. The aim of tempering is to eliminate the stress of cast steel joints and avoid deformation and cracking of cast steel joints.
Temperature and time of heat treatment is the key link, heat treatment temperature-time chart is the important data to monitor the rationality of heat treatment.