Development of hardening parameters of hard-tempered rolling steel by surface-plastic deformation
A short analysis of the known methods of choice of technological hardening parameters of machine-parts by surface-plastic deformation has been made. There are some limitations in the methods offered by the authors and these methods are general in essence. Such parameters, as the force of pressing the tool and the feed have not been calculated. Most researchers solve the tasks of the fatigue strength increase, wear-resistance, machine parts surface quality. The developed methods are directed towards the improvement of superficial layers properties. Contact-fatigue damages of machine parts develop not only on the surface but under it as well. Some authors assert that surface-plastic deformation reduces the resistances of the contact fatigue. On the basis of the results analysis, theoretical researches of the strained state of contacting cylindrical parts and experimental researches of the samples, the main provisions of hardening by a hardened-steel ball rolling that is used for making braces of supporting rolls of the mills for rolling plates have been worked out. The relations for the calculation of technological hardening parameters are given. The developed technology of surface hardening of tempered high-carbon steel has been tested experimentally for the contact fatigue. The samples which were hardened by a hardened-steel ball rolling with the calculated pressing force were of higher durability as compared to the control samples without hardening