Study on microstructure evolution and mechanical properties of similar joint of Al-Mg-Si alloy by tungsten inert gas welding

Department of Mechanical Engineering, Faculty of Engineering, Universitas Sumatera Utara, Jl. Almamater Kampus USU, Medan, 20155, Indonesia

^* Corresponding author: suprianto@usu.ac.id

Abstract

Aluminium alloys are widely used to structural material purposes, there is sometimes the welding processes are needed to join this material. One of the promising welding methods are Tungsten inert gas (TIG) can be used to join of similar or dissimilar aluminium. Their qualities are influenced by correct selected of the weld parameters. The inert gas, filler rod, heat treat, and current intensity are such important parameters. The aim of this research to investigate mechanical properties and microstructure evolution with varying welding current. In the present work the similar joint of the A6061 aluminium was carried out by TIG method by using ER 5356 filler rod, and current intensities (90A, 100A, and 110 A). The hardness and tensile strength obtained through micro Vickers and universal testing machine respectively at room temperature. The microstructure observation at heat effected zone and weld metal area with optical microscope was conducted. The results show that the TIG was successful to join A6061 which is the maximum 243 MPa of ultimate tensile strength and ±104 HV hardness acquired. It was clearly observed that the weld metal area has a finer grain as weld processes with 110 A current in comparison with other current intensities.