Research On Absorptivity Of Laser During Laser Heat Treatments

At present, it is difficult to select the best laser processing parameters during the laser heat treatment. In order to solve this problem, this thesis studies the absorptivity of laser which has a greatest effect on regulating laser parameters. The surface roughness of materials can affect the absorptivity of laser, but it's difficult to determine. This thesis deals with the roughness of the surface contour equivalently and puts forward to a caculation equation of the surface roughness effect to the material's laser absorptivity. The equation can caculate the angle of incidence laser. While nonmetallic materials' laser absorptivity is a variation function of the angle of incidence laser, the application of the equation for caculating nonmetallic materials' laser absorptivity is introduced here. Meanwhile, the impact of external electric field to metallic materials during laser heat treating is researched. After analyzing the reason why the electric field can affect the metallic material from the electromechanical aspect, and an equation on the relationship of the external electric field between the metallic materials' laser absorptivity is deduced, whose feasibility is approved by experiments. At last, this thesis analyses various factors which affect the metallic meterials' absorptivity, corrects the caculation equation of metallic meterials' absorptivity, makes a new curve of metallic materials' laser absorptivity according to some common ones, and experimentally proves the application of the caculation equation in practical production. The studies on the laser absorptivity can offer important reference to the adjustment of laser parameters in the laser heat treating.