Galvanic corrosion behavior of welded joint in marine atmosphere environment based on capillary microcell

Abstract

The kinetical behavior and mechanism of micro-galvanic corrosion of Q690 bainitic weathering steel welded joint in marine atmosphere were investigated. The results showed that a micro-galvanic corrosion cell formed among different regions of the Q690 welded joint. The kinetical behavior of micro-galvanic corrosion could be divided into four stages: the initiation and development of micro-galvanic corrosion, the decreasing of galvanic corrosion rate, the polarity reversal of galvanic couple, and the disappearance of galvanic effect. The difference of corrosion rate between Q690 steel and its welded joint is closely related to the micro-galvanic corrosion kinetic behavior.