Heat treatment process is normally needed after the
investment castings are finished. Heat treatment can help to improve the mechanical properties of those
lost wax casting. Especially for the
stainless steel investment casting, it will have better machining property after heat treatment.
The normal heat treatment processes are the following:
Tempering treatment
The main function for this heat treatment process is to decompose the carbide, thus to reduce the hardness of the castings. This can help to machine the castings easily. For ductile iron castings, tempering treatment can help to get more ferrite structure to increase the quality of the castings.
Annealing treatment
The main function for this heat treatment process is to get the pearlite and sorbite structure of the castings, thus to increase the mechanical properties of the
investment castings.
Hardening treatment
The main function of hardening treatment is to get higher hardness, thus to increase the wear resistance property.
surface-hardening treatment
The main function of surface-hardening treatment is to get a hardened layer on surface of the castings, thus to increase the wear resistance of the castings. Compare with hardening treatment, surface-hardening treatment are usually used for some special areas of castings. Induction hardening is widely used for this surface treatment process.
Precipitation hardening treatment
The precipitation hardening treatment is used to increase the strength of the castings, without changing the elongation property of the castings.