Experimental investigation on laser welding dissimilar materials between galvanized steel and carbon steel plates

Dissimilar metal plates welding between galvanized steel and carbon steel was investigated experimentally.The fiber laser and equipped robot were used in the experiment.The microstructure and mechanical properties of joints were analyzed.Based on the experiment,the influence of parameters variation such as laser beam power,welding speed and defocusing distance on the width and depth of welding seam was studied.The experimental results indicate that the width and depth of welding seam are inclined to be higher with the increase of laser beam power and the decrease of welding speed,and the surface hardness in the welded joint and heat affected zone are higher than that of base materials,and the tensile strength of the welded joint is reasonable equal to that of the carbon steel under the experimental condition.It is advisible that laser beam center offset a bit to the carbon steel side so as to prevent the uncoinciding between the centerline of joint and butt caused by the material physical properties difference,and to keep the continuity of strength and performance in the joint during the laser welding dissimilar materials between galvanized steel and carbon steel.