New proposal for the solution of thick plates lap joint problem

Abstract

The strength of laser welding with lap joints depends on its welding length and width of bead at plates interface. Therefore, the narrow bead width of laser lap welding joints at plates interface forces to apply multi-times welding to get required strength. The goal of this paper is to increase interface bead width on thick plate laser lap welding. The authors turn their attention to the penetration shapes of high power CO2 laser welding for achieve that. It is well known that penetration shapes are like a wine cup in the case of deep penetration welding using high power CO2 laser. The penetration shape of the wine cup is suggested that a large amount of laser power is absorbed at the surface of the test pieces. Then, the authors have studied how to change the heat source distribution on laser lap welding, and have succeeded to increase the bead width at the interface by a new developed process.