Dual laser beam brazing process

The experiments of dual laser beam brazing of galvanized steel sheets with automatic wire feeding were carried out, in which CuSi3 was used as filler metal. The influence of laser power, defocusing type, dual laser beam energy ratio and distance between the spots on joint quality were analyzed. The experimental results indicate that better process adaptability is found in dual beam brazing with the variation of laser power, and more excellent joint quality is obtained when negative defocusing account of parallel beam brazing is used, or the distance between the spots of tandem dual laser beams is 2 mm and the first laser beam power is larger than the second one. Moreover, optical microscope, SEM and EDX were used to analyze the microstructures and elements distribution at the interface. The results show that the base metal grain size of the dual beam brazed joint is smaller than the single beam brazed joint' s, and the coarse grain zone is narrower. At the same time, there are Fe-Si intermetallics at the interface of dual beam brazed joint.