Effect of low temperature tempering prior cryogenic treatment on carburized steels

The effect of deep cryogenic treatment on the hardness and wear resistance of carburized steels used in gears was studied. The performance of the deep cryogenic treatment on quenched and tempered (first stage of tempering) steels, increased the wear resistance but the hardness was only increased in steels tempered at 200 °C. To avoid the influence of the retained austenite, and considering this presence beneficial for its application on gears, it was stabilized prior to performing the cryogenic treatment. It is suggested the possibility of creation of nuclei sites during the 200 °C tempering, where new segregations of carbon and alloying elements could cluster during the cryogenic treatment producing an increase in the hardness.