Corrosion behavior of the high-strength low alloy steel welded joint in natural seawater

In this work, the corrosion behavior of high-strength low alloy (HSLA) steel welded joints in natural seawater solution was investigated by electrochemical and immersion tests. The experimental results prove that the corrosion resistance of the weld metal (WM) was higher than that of the base metal (BM). The scanning Kelvin probe results show that the potential distribution of the BM zone is lower than the heat-affected zone (HAZ) and WM zone. The scanning vibrating electrode technique results demonstrate that the initial attack for the HSLA welded joint majorly took place in the BM zone after immersion in natural seawater. The corrosion morphology of the HSLA welded joint after immersion was observed by scanning electron microscope. The corrosion morphology of BM and HAZ regions tends to be uniform corrosion, whereas it is mainly pitting corrosion for the WM zone.