Investigation of Susceptibility to Intergranular Corrosion of Tin-Added Austenitic Stainless Steel

The intergranular corrosion(IGC) character of tin-added B316 LX and the influence of tin addition on IGC susceptibility were investigated by DL-EPR, oxalic acid etch test and transmission electron microscopy. IGC susceptibility of B316 LX is mainly caused by the precipitation of M23C6 carbide and intermetallic Laves phase. DL-EPR test is unsuitable to evaluate the IGC susceptibility of B316 LX with long-time sensitization, because more carbides and intermetallic phases are formed at grain boundaries and inside the grains, which induce more severe IGC and pits attacks. Tin addition increases the IGC susceptibility, maybe due to diffusion of tin toward grain boundaries.