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Characteristics Evaluation of Weld Metal Zone Welded with Various Repair Welding Filler Metals

Recently, the fuel oil of diesel engine of marine ships has been changed with heavy oil of low quality as the oil price is getting higher and higher. Therefore, the wear and corrosion against all parts of the engine, such as cylinder liner, piston crown, and spindle and seat ring of exhaust valves has predominantly increased due to its consumption. Thus, the repair welding of the piston crown is a unique method to prolong its life in a economical point of view. In this case, filler metals having a better corrosion and wear resistance are mainly being used for repair welding. However, the piston crown on the ship’s job site is often actually being welded with mild filler metals. Therefore, in this study, the mild filler metals, such as E5016, E1216, and E2316, were welded to the SS401 steel as the base metal, and the corrosion properties of their weld metal zones with and without post weld heat treatment were investigated with some electrochemical methods in 0.1% H2SO4 solution. The weld metal zone welded with E1216 filler metal exhibited the best corrosion resistance among the filler metals with irrespective of heat treatment, however, its corrosion resistance was somewhat decreased due to the post weld heat treatment(annealing:625oC, 2hr). In particular, the weld metal of E2316 exhibited relatively a good corrosion resistances by the post weld heat treatment.