Improved microstructure and properties of 6061 aluminum alloy weldments using a double-sided arc welding process

Due to its popularity and high crack sensitivity, 6061 aluminum alloy was s elected as a test material for the newly developed double-sided are welding (DSAW) process. The microstructure, crack sensitivity, and porosity of DSA W weldments were studied systematically. The percentage of fine equiaxed gr ains in the fully penetrated welds is greatly increased. Residual stresses are reduced. Porosity in the welds is reduced and individual pores are smal ler. It was also found that the shape and size of porosity is related to so lidification substructure. In particular, a weld metal zone with equiaxed g rains tends to form small and dispersed porosity, whereas elongated porosit y tends to occur in columnar grains.