Temperature filed simulation of laser brazing for galvanized steel sheets

The experiments of single and dual laser beam brazing were carried out, in which the base metal is galvanized steel sheets and CuSi3 is used as filler metal. A finite element model was developed for the thermal process on the basis of heating behaviors analysis, and the transient temperature fields in the braze joint were calculated. In the model, the surface heat source was used to model laser heating the surface of filler metal and base metal, and the heat transfer induced by the flow of melted feller metal was simulated by a volume heat source. Nonlinear effect of temperature on thermal properties, latent heat, the convection and irradiative heat losses were considered. Numerical results of the temperature fields in the braze joint were obtained for typical process parameters. The results show that the temperature gradient of individual beam brazing is high, however, in dual laser beam brazing with 2 mm spot distance, the peak temperature and temperature gradient are low and high-temperature zone is wide, which is benefit to achieve good brazing quality.