Effect of Welding Method to Corrosion Property of Repair Welding Zone of Exhaust Valve
Recently a fuel oil of the diesel engine in the merchant ship is being changed with low quality as the oil price is getting up more and more. As a result, the wear and corrosion ofall parts of the engine like cylinder liner, ring groove of piston crown, spindle and seat ring of exhaust valve are increased with using of heavy oil of low quality. In particular the degree of wear and corrosion in between spindle and seat ring are more serious compared to the other parts of the engine due to operating in severe environment such as the high temperature of exhaust gas and repeating impact. Thus repair weld of the exhaust valve is a unique method to prolong the life of the exhaust valve in an economical point of view. In this study, corrosion property of both weld and base metal was investigated with some electrochemical methods such as measurement of corrosion potential, cathodic and anodic polarization curves, cyclic voltammogram and AC impedance etc. in natural sea water solution, in case of being welded with some welding methods and welding materials to the exhaust valve specimen as the base metal. In all cases, the values of hardness of the weld metals were more higher than that of the base metal. And their corrosion resistance were also superior to the base metal. The weld metal of P2F( plasma welding with 2 pass by foreign electrode) showed a relatively good corrosion resistance as well as the hardness compared to the other welding methods. Furthermore pitting potential of weld metals was nobler than base metal and P2F had also a good pitting resistance than other weld metals
Corrosion resistance Repair weld Welding materials Corrosion potential Exhaust valve
Kyung-Man Moon Hwang-Rae Cho Woo-Seok Jang Yun-Hae Kim
Dept.of Mechanical and Material Engineering, Korea Maritime Univ.Dong Sam-2Dong Young Do-Gu, Pusan, 606-791, Korea
国际会议
郑州
英文
2007-10-23（万方平台首次上网日期，不代表论文的发表时间）