Temperature distribution and melt pool size in a semi-infinite body due to a moving laser heat source

Heating and melting of a semi-infinite body due to volumetric absorption of a moving laser radiation were studied. The problem is essentially a transient three-dimensional conduction problem with a moving heat source and a moving phase boundary. An explicit finite difference technique was used to solve for the temperature distribution and the melt pool size. In order to save computing time the solution domain was divided into inner and outer regions. The inner region was sized to contain the maximum pool size. A fine grid pattern was used for the inner region, where the temperature gradient is large and where the accurate location of the solid-liquid interface is desired. In order to validate the numerical results, comparisons were made with experimental data. The results show that the heat-affected zone and the melt pool size decrease as the translational speed of the beam increases.