A study on heat flow and temperature monitoring in the laser brazing of a pin-to-plate joint

An advantage offered by laser brazing over fusion welding is that strong joints can be produced at a relatively low heat input. To minimize the thermal effects and maintain the designed dimension of assemblies, the CO₂ laser beam was applied to the brazing of joints between a pin and a hole as a micro heat source. The heat flow and temperature distribution of the brazed parts were calculated using the finite element method with a two-dimensional axisymmetric model and the surface temperature of the brazed joint was measured with laser brazing by using a infrared radiation sensor system. The laser beam mode was considered as a process parameter and its influence was predicted with respect to the temperature distribution and joint quality through finite element analysis. The measured and calculated results were compared with each other, showing fairly good agreement. Based on these results, the proper process parameters were selected to obtain a good joint quality.