Process optimization and thermo-plasticity analysis of laser welding-MIG for 6063 aluminum alloy

Abstract

The process of laser-MIG welding for 6063 aluminum alloy was optimized by the first regression orthogonal design method. Gleeble-1500 thermal simulator was used to check the thermo-plasticity. The brittleness temperature range of 6063 aluminum alloy was 470-620°C. On the basis of process optimization parameters, the welding currents: 150A, 180A and 210A, were selected for experiments. The types and causes of hot cracks were researched by means of SEM and EDS. The results show, with increasing the heat input, the welding thermo-plasticity decreases first and then increases. The crack is transformed from the liquefied crack to crystalline crack in the weld metal area. When the welding current is 180A, that is, the heat input is 3.0KJ/cm, the welding joint can obtain the best weld penetration. Its thermal plasticity is the smallest and the welding thermal crack is crystalline crack.