Technology development on dual beam laser lap welding of mg casting alloys for automotive applications

Abstract

Magnesium casting alloys have many desirable attributes that make them attractive materials for automotive applications. Some of these attributes include; high specific strength and stiffness for weight reduction, improved sound dampening capability compared to steel and aluminum, and electromagnetic interference shielding ability. Laser welding, which is a highly desirable methods of joining automotive body materials, due to its ability to provide high productivity and structural integrity has been considered for magnesium. However, there is a major challenge for laser welding of Mg alloys: the propensity of porosity formation within the weld. In this paper, the porosity formation mechanism and the factors that influence the porosity formation in a lap joint will be discussed first. Second, a new technology based on dual beam welding will be introduced and elaborated upon, along with recent preliminary results which show that this newly developed technology can significantly reduce porosity and achieve improved quality welds at higher welding speed.Magnesium casting alloys have many desirable attributes that make them attractive materials for automotive applications. Some of these attributes include; high specific strength and stiffness for weight reduction, improved sound dampening capability compared to steel and aluminum, and electromagnetic interference shielding ability. Laser welding, which is a highly desirable methods of joining automotive body materials, due to its ability to provide high productivity and structural integrity has been considered for magnesium. However, there is a major challenge for laser welding of Mg alloys: the propensity of porosity formation within the weld. In this paper, the porosity formation mechanism and the factors that influence the porosity formation in a lap joint will be discussed first. Second, a new technology based on dual beam welding will be introduced and elaborated upon, along with recent preliminary results which show that this newly developed technology can significantly reduce porosity and achieve i...