Laser welding of zinc-coated steel with tandem beams: Analysis and comparison

A new method of using two tandem laser beams for lap welding of galvanized steel sheets is being discussed and modeled along with its comparative study. This involves a pre-cursor beam and a higher-power actual beam, generated independently or otherwise split from the same source. The first beam cuts a slot, thus making an exit path for the zinc vapours, while the second beam performs the needed welding. The paper discusses some early experimental results of the method, including the metallurgical analysis obtained in laboratory showing total absence of zinc in the weld area. A comparison of the proposed system with other techniques proposed in the recent years is also drawn along with some quantitative analysis. General analysis in industrial perspective also supports this method to be easier to implement on the production lines, along with entailing some process time saving.