Cementation process improves surface hardness, abrasion resistance and continuous strength, as well as improves part core region strength and ductility. In this way, it is ensured that large loads are transported and loads in impact style are met.
Cementation materials carbon ratio is generally between 0.10 - 0.20%, in some varieties it can be up to 0.25%. They can be produced with or without alloy.
Cementation steels can be heat treated in different ways after cementation. After the cementation process, the amount of carbon in the core region remains at 0.10% - 0.20, while the amount of carbon in the surface region rises up to 0.8%. In this case, the choice of heat treatment temperature becomes difficult due to the varying amount of carbon all over the part structure. The temperature to be selected based on the core region causes grain size in the part wall region, and the temperature to be selected based on the part wall region causes the core region not to harden sufficiently. For this reason, the easiest method to be applied is direct hardening from the cementation temperature. This method can be applied only after salt bath and gas cementation. The method is more suitable for fine-grained steels.
Core strength can be increased by increasing the amount of carbon in cementation steels and with the added alloy elements. However, the most efficient result can be achieved with core hardening after cementation. This method is called double hardening. The part that is cooled suddenly from the appropriate curing temperature of the core region is subjected to intermediate annealing, and then the hardness of the wall region is obtained by cooling the curing temperature suitable for the wall region.
Welding ability of case hardening steels is good. Alloy steels require annealing after welding. Machining is best achieved with normally annealed or coarse grained material. Softened material is not preferred because it gives bad surface quality.