Hardening of long steel products by shot peening

Abstract

The negative effect of surface defects and a decarburized layer on the cyclic resistance of steel products is shown. Information about the places of destruction of parts in operation and during bench tests are presented. The use of shot peening of long-length steel products of complex configuration in relation to the hardening of the surface layer of parts by methods of thermochemical treatment and high-frequency hardening is justified. The technology of work hardening of the surface layer of the truck front axle beam has been developed. After straightening long-length parts to eliminate warpage and achieve geometric accuracy, shot peening is performed. It is recommended to use DSLU – 2.2. steel shot for hardening. Information on the structure, grain composition and hardness of various types of shot are presented. Processing parts with shot is carried out for 20 minutes. An increase in the microhardness of the surface layer by 77HV in relation to the hardness of the base metal of the part was established. As a result of hardening of the surface layer, the cyclic resistance of the front axle beam exceeded 1 million 400 thousand cycles. A device for assessing the degree of hardening by shot of the truck front axle beam has been developed and implemented. The basis of the device is a beam on which Almen plates are installed in the recesses. The plates are located in different parts of the part and take into account the features of its configuration and the most loaded areas in operation.