Abstract: A carburization and heat treatment process of a machine part for obtaining different depths of carburizations in different surfaces of the machine part. The process consists of the steps of; deep carburization of a partly preformed blank of the machine part (FIG. 2A and 2B) to a suitable depth of carbon penetration, machining the partly preformed blank to desired sizes (FIG. 1A and 1B) thereby partly or completely removing the carburization in not preformed dimensions of the blank, shallow carburization of the machined machine part to a desired depth of carbon penetration, and finally heat treating of the machine part.