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 design dimension of assemblies, the $CO_2$ Laser beam was applied to the brazing joints between pin and hole as a micro heat source. The heat flow and temperature distribution of brazed parts were calculated by using the finite element method with a three dimensional axisymmetric and asymmetric model. And the source temperature of the brazed joints was measured in laser brazing by using a infrared radition sensor system. The laser beam mode was also considered as a process parameter, and its influence was predicted with respect to the temperature distribution and joint quality through the finite element analysis. The results measured calculated were compare with each other, which show a good agreement. Based on these results, the proper process parameter were selected to get a good joint quality. Also process monitoring to get good quality is enabled by analysis of IR signal.
