An experimental study on the quality of hardfacing layer through resistance seam welding

Shaft-shaped parts work normally in wear-resistant conditions. Over time, the shaft might experience wear and fail to maintain the required size, affecting its workability and efficacy. This study examines the hardfacing layer quality of a restored steel shaft obtained through resistance welding. The researchers of this study designed nine welding conditions according to Taguchi's experimental matrix and applied each to experimentally weld steel shaft samples. A recovery welding machine system, which includes a resistance seam welding machine combined with a designed fixture, was used to weld the samples. The experimental results revealed that the welding layers’ surface is flat and has no surface defects. Meanwhile, the hardfacing layer and the retorted shaft surface have good cohesion, as observed through macrostructure photography. The hardness and wear resistance of the hardfacing layer were relatively high and closely resembled those of a new high-frequency quenched steel shaft. The influence level and the relationship of the welding parameters on hardness and wear resistance were also considered in this study. In addition, this study proposes the appropriate welding conditions for obtaining the highest hardness and the smallest worn metal weight. The findings presented in this study offer valuable insights for mechanical manufacturers engaged in the reconditioning process of shafts, aiding in time and cost savings.