New considerations and experimental results on laser lap welding of zinc coated steel sheets

Abstract

Laser welding of zinc-coated steel sheets in lap configuration poses a challenging problem, because of the zinc vapors spoiling the quality of the weld. Laser lap welding of zinc-coated sheets needs still investigations in order to be properly inserted in production line. We have investigated several methods and propose a combined solution of cutting a slot and welding it over by a combined tandem of laser beams. We present theoretical and experimental work. We propose another solution, which should be easier to implement in production and not only limited to zinc coated steel sheets but also useable with aluminum alloys. This solution utilizes adaptive optics in order to adjust in real time the laser beam wave front profile to slow the keyhole cooling to exhaust zinc vapors.Laser welding of zinc-coated steel sheets in lap configuration poses a challenging problem, because of the zinc vapors spoiling the quality of the weld. Laser lap welding of zinc-coated sheets needs still investigations in order to be properly inserted in production line. We have investigated several methods and propose a combined solution of cutting a slot and welding it over by a combined tandem of laser beams. We present theoretical and experimental work. We propose another solution, which should be easier to implement in production and not only limited to zinc coated steel sheets but also useable with aluminum alloys. This solution utilizes adaptive optics in order to adjust in real time the laser beam wave front profile to slow the keyhole cooling to exhaust zinc vapors.