Laser Sintering of Tungsten Carbide Particles on AISI 304 Steel Surfaces: Modelling of the Temperature Field

Laser heating of AISI 304 steel surfaces is modelled and the temperature field in the irradiated region is predicted numerically. The steel surface is considered to be composed of uniformly distributed tungsten carbide particles of 2.5 mm diameter while resembling the laser sintering process. The effect of the laser beam radius on the temperature field is investigated for the same configuration of particle distribution in the irradiated region. The phase change process taking place during the heating process is modelled by using the enthalpy-porosity method and resulting melt fraction ratios are predicted in the irradiated region. Experiment were carried out using a CO2 laser to verify the predictions of the melt layer thickness for various laser beam radiuses. It is found that the melt depth predicted for various laser beam radiuses agree well with their counterparts obtained from the experiment. The maximum temperature in the melt pool is higher than the melting temperature of steel; however, it is lower than the melting temperature of the tungsten carbide particles. The melted region composes of the liquid and the mushy zones. The size of the liquid zone increases with increasing laser beam radius. The same argument is true for the mush zone.