The heat treatment of P/M materials includes quenching heat treatment, chemical heat treatment, steam heat treatment and special heat treatment. In a word, the purpose of heat treatment is to make the powder metallurgy process used to obtain the required microstructure and properties. The steel is used for surface hardening through endothermic atmosphere. A layer of oxide is formed to improve the hardness, wear resistance, strength and fatigue resistance of the product, especially for the anti-corrosion of the surface of powder metallurgy materials.

The carbon rich layer on the surface is very effective, but the control of carbon is a common problem in the powder metallurgy process. During the sintering process, the product should be fully decarburized, and then re carbonized to achieve the effect of surface rich carbonization, which increases the surface hardening of powder metallurgy parts.

The heat treatment process of powder metallurgy materials is a complex process, which is related to porosity, alloy type, alloy element content and sintering temperature. Compared with compact materials, the internal homogeneity is poor. To obtain higher hardenability, it is necessary to improve the complete austenitizing temperature and extend the time. Uneven austenitic carburization can obtain a high carbon concentration that is not limited by the saturated carbon concentration of austenite. In addition, the addition of alloy elements can also improve the hardenability. Steam treatment can significantly improve its corrosion resistance and surface hardness.