Влияние параметров плазменного упрочнения на качество поверхностного слоя тяжелонагруженных изделий

Abstract

There has been studied the effect of the hardening current, the distance between the nozzle and the hardened surface of the product, the flow rate of the plasma-forming gas, the dependence of the cooling rate during plasma hardening on the speed of the plasma torch movement (treatment speed), and the diameter of the nozzle. Based on the theory of thermal processes, the cooling rates have been calculated for various values of the current strength. It has been shown that the ratings characterizing the significance of the main technological parameters of the plasma hardening mode for the depth and width of the hardened zone are practically the same. While the effect of the current strength on the dimensions (depth and width) of the plasma hardening zone significantly exceeds the effect of the other parameters of the hardening mode. This indicates that the arc current is the main controlled parameter of the plasma hardening process. There has been shown the possibility of regulating the mechanical properties of the hardened surface of the solid-rolled railway wheel rim depending on the required level of mechanical characteristics by means of controlling the speed of the wheelset.