Plasma manual hardfacing on nuclear valves

Nuclear energy production advances are essential to meeting projected world energy needs. Safe, continuous plant operation will guarantee the generation of this energy. Within nuclear power plants, valve service is critical to daily operation and maintenance and plant emergency controls. To increase nuclear stainless steel valve quality and reliability, the Westinghouse Electro-mechanical Division has selected manual plasma transferred arc hardfacing for three critical wear applications - backseat ring bore, gate wedge guide surface, and gate disc guide lug. The manual plasma process was initially compared with these alternatives - gas tungsten arc, shielded metal arc, and oxy-acetylene hardfacing. The considerations influencing process selection were: customer and engineering design requirements, materials, manufacturability, and relative costs. Process selection and implementation elements and current production controls have accomplished superior finished component quality. (Author)