The double-wire feed and plasma arc additive manufacturing process for deposition in Cr-Ni stainless steel

Abstract

This paper proposes an innovative and high efficiency process to fabricate Cr-Ni stainless steel components using a double-wire feed and plasma arc additive manufacturing process (DWF-PAM). The superior characteristics exhibited by DWF-PAM processing in terms of the bead appearance, microstructure, and mechanical properties of all the test components, were investigated. The results show that, at the same process parameters, in contrast to the single-wire feed and plasma additive manufacturing (SWF-PAM) process, the deposition rate in the DWF-PAM process increased by 1.06 times on an average. A large number of complete grown equiaxed ferrite (CGEF) grains were found in the interface area close to the next layer of the DWF-PAM-processed sample; while for the SWF-PAM-processed samples, incomplete grown equiaxed ferrite grains were observed in same area. The CGEF grains provided a significant improvement to the ultimate tensile strengths and elongation rates of the DWF-PAM-processed samples. The ultimate tensile strength increased by 10.2% on an average, while the maximal increment of the elongation rate reached 176%. In view of these results, components manufactured by the DWF process can have a finer-grained microstructure and superior mechanical properties compared to those manufactured by the SWF process. Moreover, a higher deposition rate can also be achieved with the DWF-PAM process.