Effects of welding current on the shape and microtructure evolution of thin-walled low-carbon parts built by wire arc additive manufacturing

Abstract

Wire are additive manufacturing (WAAM) is nowadays gaining much attention from both the academic and industrial sectors for the manufacture of medium and large dimension metal parts because of its high deposition rate and low costs of equipment investment. In the literature, WAAM has been extensively investigated in terms of the shape and dimension accuracy of built parts. However, limited research has focused on the effects of welding parameters on the microstructure characteristics of parts manufactured by this process. In this paper, the effects of the welding current in the WAAM process on the shape and the microstructure evolution of thin-walled low-carbon steel components were studied. For this purpose, the thin-walled low-carbon steel samples were built layer-by-layer on the substrates by using an industrial gas metal arc welding robot with different levels of the welding current. The shape, microstructures, and mechanical properties of the thin-walled samples were then analyzed. The obtained results show that the welding current plays an important role in the shape stability, but it insignificantly influences the microstructure evolution of thin-walled samples. The increase in the welding current only leads to a coarser grain size and decreases the hardness of each zone of the walls. The mechanical properties (i.e. hardness and tensile properties) of the WAAM thin-walled low-carbon steel parts are also comparable to those of wrought low-carbon steel, and to be adequate with real applications.