31 船体溶接部に生じる溝状腐食に関する実験的検討

概要

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In late years the accidents due to hull structural deterioration over time occurred frequently. In particular the hull strength deterioration due to grooving corrosion occurring on welded joints for ship structure is one of the main problems for ship safety. Therefore it is important to elucidate about growth mechanism of grooving corrosion. In this paper, continuous immersion tests in seawater using working stressed and pre-strained specimens were carried out to investigate the effect of working stress and plastic strain on corrosion rate, namely, stress corrosion. It becomes clear that corrosion rate is not influenced by working stress and plastic strain, but corrosion accelerates because a new area is formed if the rust of stress concentration part exfoliates by an active deformation, etc.. Moreover electrochemical tests using specimen with fillet welded joint were also carried out to measure corrosion potential of base metal and weld metal and to observe galvanic corrosion. From the above experimental results and observation result of grooving corrosion of welded joint collected from a ship, it is considered that grooving corrosion occurring on welded joints should grow up by galvanic corrosion and stress corrosion.
社団法人日本船舶海洋工学会の論文