Laser welding of additively manufactured medium manganese steel alloy with conventionally manufactured dual-phase steel

Abstract Additive manufacturing (AM) of vehicle components is becoming increasingly important for faster development and economic reasons. The challenge lies in joining additively manufactured structures with conventionally manufactured components. For this purpose, a new steel alloy additive powder with medium manganese concept has been developed, which mimics the properties of automotive dual-phase steel. The focus of this paper lies on the investigation of laser weldability of this AM powder in order to achieve hybrid structures that fulfill both economic and mechanical requirements. AM test specimens of the developed alloy were manufactured using a laser-powder-bed-process. Starting with the welding of similar types of additive-powder-alloy, the combination of additive and conventional galvanized steel (HCT780XD) was considered for investigation. The resulting microstructures and the determined mechanical properties indicate a good weldability of this material. The results show laser typical and low-distortion weld seams, whereby hardening occurs in the weld seam. Moreover, the high roughness of the AM components assists a complete zinc-outgassing.