The Corrosion Behaviors of Welded Joints of 3C Carbon Hull Structural Steels

Two kinds of carbon hull structural steels (the 3C steel which is Re-free and the 3C corrosion resistant steel which is modified by Re) and three kinds of welding consumables are selected and made into six kinds of welded joint specimen.The difference of corrosion behaviors of six welded joint specimen and distinct zones of the welded joint specimen have been investigated by means of laboratory stirring immersion test,dry-wet intermittent test and constant potential anodic dissolution test.Furthermore,conbined with the metallurgical analysis,the reason which makes these corrosion results are discussed.The results indicate that the weld zone and base metal show more corrosive than the heat affected zone(HAZ),while the weld zone is easier to corrode than the base metal.Not only is the corrosion resistance of structural steel improved itself with Re additions,but also the corrosion resistance of the steel welded joint is also improved correspondingly (compared to the same welding consumable).For Both the 3C steels which are Re-free and the 3C corrosion resistant steel which is modified by Re,the corrosion resistance of welded joint using J422 consumable is higher than using other two welding consumables.