There are many types of heat treatment in precision casting, which can be mainly divided into two categories: firstly, the organizational structure does not change through heat treatment, and secondly, the basic organizational structure changes.
For the second type of heat treatment, significant changes have occurred in the organization, which can be roughly divided into five categories:
1. Softening annealing: mainly depends on decomposing carbides, reducing their hardness, and improving production characteristics. For ductile iron, it depends on obtaining a large amount of ferrite structure.
2. Normalizing treatment: obtaining pearlite and sorbite structures to enhance the mechanical properties of stainless steel casting.
3. Quenching treatment: mainly to achieve higher hardness or wear strength, while also achieving high surface wear resistance characteristics.
4. Surface hardening treatment: mainly to obtain a surface hardening layer while obtaining high surface wear resistance characteristics.
5. Precipitation hardening treatment: mainly used to obtain high strength without causing drastic changes in elongation.