Initial Corrosion Behavior of High Strength Low Alloy Steel Welded Joint in Seawater

The initial corrosion behavior of high strength low alloy steel welded joint in seawater was studied by electrochemical methods and surface analysis. The results show that the base metal zone with low initial potential displayed the highest corrosion tendency before immersion. After immersion in seawater, the surface potential of base metal zone showed the largest fluctuation. The welded joint exhibited a transition of anodic dissolution from high speed to low speed during the initial corrosion, and the base metal zone of the joint had the highest current density. The initial corrosion process of welded joint developed in two forms of general corrosion and pitting corrosion in seawater. The composition of the corrosion products was mainly composed of α-Fe₂O₃, α-FeOOH and γ-FeOOH. The corrosion resistance of different zones of the high strength low alloy steel welded joint in seawater increased in order of base metal zone, heat affected zone, weld zone, at the initial stage of immersion in seawater.