Formation of structure and properties of surface layer of case-hardened steel by electromechanical surface hardening

The researching results of the structure and microhardness of the surface layer of steel 20 after vacuum cementation of cylindrical samples to a depth of 1,0 mm and their hardening by volumetric heat treatment in comparison with electromechanical surface hardening are presented. The maximum microhardness of the surface layer of cemented steel 20 is at a depth of 0,05 mm and corresponds to 9650 HV MPa, and gradually decreases within the hardened layer to 8190 HV MPa at a depth of up to 0,75 mm after electromechanical surface hardening has been experimentally established. There isn’t decarbonized layer after the electromechanical surface hardening of cemented steel samples 20. The reaserch practical significance is associated with the possibility of improving the quality and reducing the cost of parts producting from cemented steels by replacing heat treatment after cementation with the technology of hardening the working surfaces by electromechanical surface hardening.