CMT-based wire arc additive manufacturing of Inconel 625 alloy

Abstract

Cold metal transfer (CMT) technology is considered in an application for wire arc additive manufacturing (WAAM) of refractory highly corrosion-resistant Inconel 625 alloy. Based on the fabricated wall, the suitability of CMT–WAAM for the sound formation of welds and homogeneous distribution of mechanical properties is shown. Microscopic analysis reveals that the microstructure of the deposited alloy along the height of the wall element is relatively uniform. Minor differences in the microstructure are observed in the bottom part, caused by welding specifically. It should be noted that there is a slight decrease in strength indicators from the bottom to the top of the welded product, but they do not exceed 5%, which is considered entirely satisfactory. This phenomenon is caused by structural transformations that take place under slightly different cooling conditions – namely, in the lower layers. The substrate on which the surfacing is carried out plays a more significant role in heat flow. This leads to more intensive cooling of the lower layers and, as a result, slightly higher values of strength.