Due to the different purposes of precision castings, there are many heat treatments, which can be basically divided into two major categories. The first category is that the structure of the structure will not change or should not be changed through the heat treatment, and the second is the basic structure. The first heat treatment procedure is mainly used to eliminate internal stress, which is caused by the different cooling conditions and conditions during the stainless steel casting process. The structure, strength and other mechanical properties do not change significantly due to heat treatment.
For the second type of heat treatment, al-Qaeda has undergone significant changes and can be roughly divided into five categories:
1. Softening annealing: The purpose is mainly to decompose carbides, reduce their hardness, and improve the processing performance. For ductile iron, the purpose is to obtain more ferrite structure.
2. Normalizing treatment: The main purpose is to obtain pearlite and sorbite structure to improve the mechanical properties of stainless steel casting.
3. Quenching treatment: Mainly to obtain higher hardness or abrasion strength, and at the same time to very high surface wear resistance.
4. Surface hardening treatment: mainly to obtain a surface hardening layer and at the same time to obtain very high surface wear resistance.
5. Precipitation hardening treatment: mainly to obtain high strength and the elongation does not change drastically.