Cementation as a type of chemical heat treatment plays the important role in the treatment of metal that combines chemical and thermal effects on the metal to change the properties and composition of the part, namely the saturation of the outer layer of carbon at a temperature of 850-950 °C. This treatment is applied to parts that are exposed to high temperatures. The treatment is applied to parts with hard-wearing working surfaces and ductile core, e.g. gears (chevron, cylindrical and bevel), crankshafts, worms, pinion shafts, axles, camshafts, keys, cams etc.