Heat treatment of precision castings

Due to the different purposes of precision castings, there are many types of heat treatment, which can be mainly divided into two categories. The first type is that the microstructure will not change or should not change through heat treatment, and the second type is that the basic microstructure changes. The first heat treatment program is mainly used to eliminate internal stress, which is caused by different cooling conditions and conditions during the stainless steel casting process. The organization, strength, and other mechanical properties shall not undergo significant changes due to heat treatment.

For the second type of heat treatment, there have been significant changes in Al Qaeda, which can be roughly divided into five categories:

1. Softening annealing: Its main purpose is to decompose carbides, reduce their hardness, and improve processing performance. For ductile iron, its purpose is to obtain more ferrite structure.

2. Normalizing treatment: The main purpose is to obtain pearlite and sorbite structures to improve the mechanical properties of stainless steel casting.

3. Quenching treatment: mainly to achieve higher hardness or wear strength, while also achieving very high surface wear resistance characteristics.

4. Case-hardening treatment: mainly to obtain Case-hardening layer and obtain very high surface wear resistance.

5. Precipitation hardening treatment: mainly for obtaining high strength, the elongation does not change drastically.