Modeling of energy absorption in steel during its treatment by powerful high-frequency pulses of varied frequency

Based on the previously developed model of thermal, electromagnetic, and structural-phase processes in surface layers of carbon steels under the action of high-frequency pulses, the heat release in these layers in the range of allowable field frequencies from $66$ kHz to $40.12$ MHz is studied. The specific energy flux of the electromagnetic field is considered as the basic energy parameter characterizing the intensity of high-frequency treatment. Frequency dependences of the dynamics of steel heating up to the liquidus point for treatment regimes important for practice with $\langle W\rangle=10^8$ and $2\cdot10^8$ W/m$^2$ for the width of the pulse-action zone on the steel surface equal to $1.5$ and $4$ mm are obtained. The data of numerical calculations are used to construct the specific flux of energy as a function of the maximum surface temperature; together with the results of numerical simulations of structural-phase transformations in the steel grain, these dependences allow one to choose the optimal hardening modes at different frequencies.