Innovative solutions for improvement of operation reliability of parts with stress concentrators

Comparative data concerninf the safety factor of parts made of 45, 40Х, 12XN3A, St.6ps steels, hardened according to different technological schemes, is presented. The use of 40X steel for the manufacture of car ball pins is proposed. A technology of heat treatment of workpieces with the use of water solutions of polymers for quenching is presented. A technology of surface quenching of parts with high-frequency heating currents has been developed. Recommended depth of the hardened layer is 1.5-2.0 mm over the entire surface of the part, excepting its threaded part. Structural studies and results of bench benching test of parts are presented. The technologies of thermal hardening of workpieces and surface hardening of ball fingers of 40x steel for trucks have been introduced into production. Durability and high performance of the parts in operation are achieved by forming a heterogeneous structure in the section of the part: martensite on the surface and sorbite in the core.