Localized Depth of Galvanic Corrosion of Dissimilar Metal Welding A508/Inconel 182/316L

Abstract

The nickel-based Inconel 82/182 alloy was used as a filler for GTAW welds to produce the A508/Inconel-182/316L dissimilar weldment. The depth of galvanic corrosion was related to the change in potential and current density using the potentiodynamic polarization test and the morphology of the depth of galvanic corrosion was investigated thoroughly. The results showed that A508 low alloy steel generally suffered from corrosion attack, but the most severe corrosion attack was found in the weld joint interface area of A508/Inconel 182 low alloy steel joints due to the effect of galvanic corrosion. This symptom will not be seen if observed on the outside of the surface alone, but severe symptoms occur in the area of the inner side of A508/Inconel 182 weld joint. And also, in the joint of surface area, corrosion products such as Fe₃O₄ and scale were produced. Finally, there has been a change in the slits and concave shape (depth of galvanic corrosion effect) of the interface of weld joint between the Inconel 182 and low alloy steel A508, due to the effect of galvanic corrosion with changes in potential, current density and immersion time of dissimilar welding materials.

Keywords: Corrosion depth, dissimilar welding, galvanic corrosion, low alloy steel A508, and stainless steel 316L.