Optimization of laser beam welding of steel parts made by additive manufacturing

Abstract

To pursue all the benefits of additive manufacturing of metals, recent studies have been aimed at assessing a proper welding technology to obtain large products by means of joining smaller parts. Indeed, at present, two or more parts must be manufactured individually and then assembled to produce the final component, when the size is incompatible with the building chamber or severe deformations arise during building. In this paper, laser beam welding is explored to join stainless steel components made by the process of laser powder bed fusion, in order to benefit from all the known advantages of this joining technique, aiming at producing a welding bead with homogeneous mechanical features with respect to the unwelded counterpart: a factorial plan is built, and the response surfaces are presented; then, the consolidated method of the desirability function is used to find the optimum condition of welding with reference to the current international standards, taking into account the geometry, the welding imperfections, and the extent of the heat-affected zone. The suggested optimum is eventually assessed via tensile testing and compared to the unwelded sample.