Papers by Author: Yong Hua Xiang

Abstract: The micro-plasma arc welding technology（MPAW） was used to remanufacture the exhaust valve of W615 engine. The ST6 Co alloy powder was selected as overlaying material, the processing parameters of overlaying was optimized considering the geometry demand of deposited layer, and the current downslope method was adopted to weaken the arc crater. The microstructure characteristics and the micro-hardness of the weld were investigated, no defects were found in the deposited layer or at the interface, and the heat-affected zone among joint was not evident. The maximum hardness situated at the top layer being 657.8HV, with a slight decrease towards the bottom layer and fusion zone.

Abstract: The thrust surface of W615 engine is remanufactured by plasma transferred arc (PTA) powder surfacing technology. The Ni15 Nickle-based alloy powder is selected as deposited metal. By optimizing the welding procedure, the coating is free of crack and pore. The microstructure characteristics of deposition layer are investigated by metallographic microscope, and the microhardness of the overlay is measured by vickers hardness tester. It is found that the heat affected zone is narrow, the rate of dilution is low and the microhardness of deposition layer is about HV130 which is close to that of base metal. Furthermore, the hardness of welding surface can meet the needs of the engine.