The Influence of Current on Laser Welding on Mechanical Properties and Micro Structures of Dissimilar Metal Joints

Abstract

The joints of dissimilar metals have several problems because they have different mechanical properties and microstructures. This problem can be solved by using laser welding because the resulting energy focus and hot zone around the welding joint is minimal. The parameters that are important in welding either using welding laser or other welding process is the current. Thus, this study examined the joint of dissimilar metals i.e low carbon steel (mild steel A36) and stainless steel (stainless steel 304) using laser welding. The result of the laser welding joint with a strong variation of current tested its mechanical properties with tensile test and seen its micro structure with photo Scanning Electron Microscopy (SEM). Tensile test results on the current variable 410 - 440 Ampere obtained fracture is on the side of mild steel A36, while at 450 Ampere current strength obtained a fault on the laser welding joints, where the point of the break is below the point of broken mild steel A36. Based on the tensile test, the suitable current strength for nonlinear steel joint of A36 mild steel with stainless steel 304 is 410 - 440 Ampere. In the result of the SEM photo, it is seen that on all variables of the current strength is obtained a photo of the porosity. Based on the microstructure, it is obtained that the results of laser welding are not perfect. This causes easy corrosion and cracks occur so that the laser weld tensile test results are initially good, after some time the results will go down.