Weld strength improvement for Al alloy by using laser weaving method

Laser welding of aluminum alloys usually produces linear welds that have shear-tensile strength lower than that of the base metal. This is usually due to porosity resulting from an unstable keyhole and cracking which is related to the high crack sensitivity of many of these alloys. In this work laser weaving is used to improve the joint strength of laser welds. In this research, lap welds and bead-on-plate welds were produced on 1 mm thick aluminum alloy sheets using various weaving schemes. When the weaving width was 4 mm, crack propagation was reduced, compared with a weaving width of 2mm. No cracks occurred when the weaving frequency was 5 Hz for weaving widths of 2 and 4 mm. The shear-tensile strengths were measured according to the weaving parameters such as weaving width and frequency. The laser weaving increased the fusion line length, therefore improving the joint strength. (C) 2010 Loser Institute of America.