Discussion on intergranular corrosion of stainless steel
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At room temperature, stainless steel can also suffer from intergranular corrosion in these media. Why is that? Does this not meet the definition of intergranular corrosion?
When austenitic stainless steel is exposed to sensitization temperatures, intergranular corrosion occurs in specific media. Unstable austenitic stainless steels with a carbon content exceeding 0.03% (i.e., 0Cr18Ni9 stainless steel without titanium or niobium) are prone to intergranular corrosion in certain environments if not heat-treated properly. When these steels are heated between 425 and 815°C, or when cooled slowly through this temperature range, intergranular segregation occurs. Such heat treatment leads to the precipitation of carbides at the grain boundaries (sensitization), and it also results in chromium depletion in the adjacent areas, making those areas susceptible to corrosion. Sensitization can also occur during welding, causing subsequent localized corrosion in the weld heat-affected zone.