Laser Beam Welding of 6013 Aluminum Alloy Sheet using Different Filling Powders

Abstract

Butt welds of 1.6 mm thick sheet of the alloy 6013-T4 were produced using a Nd-Yag laser and filler powders of different aluminum alloys. Microstructures, hardness, tensile properties and the corrosion behavior of the welds were investigated in the as-welded condition and in the post-weld heat treated T6 temper. A dendritic solidification structure with interdendritic eutectic phases was observed in the fusion zone. Porosity was the prevailing weld defect. Artificial aging resulted in an increase of hardness in the fusion zone, indicating precipitation strengthening in the weld region. Joint efficiencies depend upon the filler powders used. Values between 75 and 90 % were achieved for as welding joints. When heat treated to the T6 temper, the weld exhibited strengths ranging from 70 to 90 % of the ultimate tensile strength of the base alloy 6013-T6. As indicated by cyclic acidified salt spray testing, the corrosion behavior of the welds was similar to that of the base material, which was sensitive to pitting. Joints in the as welded condition were found to be susceptible to stress corrosion cracking in the heat affected zone.