A straightening fracture of an AISI 1045 pump rod with a fused coating by thermal spray welding was investigated. The fracture surface was surveyed for pinhole-related defects in the coating, debonding at the coating/substrate interface, and fracture initiation points. The base metal and coating were also examined using an optical microscope, scanning electron microscope with energy dispersive spectroscopy, tensile testing, and microhardness testing. The base metal rod experienced softening due to the thermal effect of spray welding and fusion. Large residual stress has been found in the outer coating layer using finite element analysis. The open-to-surface crack in the base metal was found to be partially filled by the hard coating. The brittle fracture is believed to be initiated at defects near the coating/rod interface and driven by a combined loading of thermal residual stresses and the applied straightening stress. © 2021 Elsevier Ltd