Cold Treatment Of Steel

Property Changes Of Steel After Cold Treatment

Cold treatment is closely related with heat treatment or we can say cold treatment is the extension of heat treatment. After cold treatment, because of the transferring of remained austenite and increasing of martensite, the hardness of steel will increase.

Attentions In The Cold Treatment Of Steel

• 1.Cold treatment should be carried out immediately after quenching and cooling the steel parts to room temperature. Since in the quenching and cooling process there is stabilization effect of austenite, in order to cooling the steel parts to room temperature and get more martensite in the later cooling, cold treatment should be carried out immediately.
• 2.The volume of martensite transferred from the remained austenite is decided by the cooling temperature reached. The transformation from remained austenite to martensite is finished instantly, so we do not need to keep the steel parts in low temperature for long time. What we need to do is to cooling the steel parts completely from inside and outside.
• 3.The cold treatment will lead to the increasing of remanent stress in steel parts; also there might be some harmful changes about the mechanical property of steel. If the steel parts are not properly handled, the parts will crack, so after cold treatment, we need to temper the steel parts immediately.
• 4.In order to reduce the stress and distortion of steel parts and reduce the volume of remained austenite, the quenching temperature should be as low as possible. In the process of cold treatment, we should slowing cooling the steel parts to below 0℃.