Gap bridging ability in aluminum laser welding

Abstract

In this paper the gap bridging ability of a 4 kW Nd:YAG laser while welding two types of aluminum is studied: cast alloy AlSiMg10 and wrought alloy AlMg4.5Mn0.4. The samples had constant growing gap that reached a maximum of 1.5 mm and 1.0 while having a 1.5 mm thickness and 2.0 mm gap while having a 6.0 mm thickness. Welds, both with and without filler wire, were produced by varying laser power, welding speed, filler wire feeding speed and defocus. The parameters were tuned aiming to achieve a good weld surface quality and an optimum amount of heat into the weld pool. The found results are that aluminum suffers considerably with sagging because of the low viscosity of its liquid phase. When defocus is increased no increased gap bridging was observed as the sagging phenomenon was also increased due to the higher amount of base material melted. Ideal parameters were found for each type of sample.