Simulation of thermal processes in a half-space under heating by a moving source with a uniformly distributed heat flow

Abstract

Using the method of applying instantaneous point sources, a solution was obtained to the problem of heat conduction during surface heating of a body in the form of a half-space by a uniformly distributed highly concentrated heat flux moving at a constant speed along a rectilinear trajectory with a different shape of the heating spot at constant thermophysical characteristics of the material. The effect of temperature loading modes and the shape of the heating spot on thermal processes in the heat-affected zone is studied. The surfaces and lines of the temperature level are constructed for different moments of time and speed loading modes in different planes of the heating zone. Time dependences of temperatures, heating and cooling rates for body points are given. The shortcomings of the methods used for linear thermal conductivity, the lack of direct consideration in the design scheme of the surface melt zone of the material do not allow one to reliably assess the effect of heat treatment modes on changes in material properties, focusing only on the level of the maximum design temperature. In this regard, the structure formation of metal in the zone of thermal action is proposed to be associated with a thermal impulse, i.e. the total thermal energy perceived by the material at a given point of the body, as well as with the effective structurization impulse introduced into consideration, which characterizes the energy spent on the process of structural transformations of the material, and the structurization time at a point and some volume of the body. The dependencies of these values on the speed of movement and the shape of the heating spot are presented. The considered approaches can be applied to various metals and alloys. The research results can be used to develop more effective methods for determining the optimal modes of surface hardening of metal products with a high-energy source.