Abstract
Detailed data on sensitization behavior of low carbon grade stainless steels have been obtained because such data are essential in establishing fabrication procedures for the construction of chemical plants. Experiments consisted of testing 304L and 316L stainless steels in nitric acid or acid sulfate tests. Carbon contents in the low carbon grade range (0.012%, 0.022%), cold work, and post-fabrication heat-treatment were the parameters of main interest. All specimens were tested after sensitizing heat treatment in the laboratory. The sensitizing region in the TTS curve expands with an increase in carbon even in the low carbon range tested. Cold work also expands the sensitizing region either in the shorter time direction (304L) or higher temperature direction (316L). Annealing 304L at 920°C followed by air cooling removes the detrimental effects of previous cold work. Similar treatment is not as effective with 316L. When the cooling rate is low, i.e., 60°C/hr, the adverse effect remains; intercrystalline corrosion of cold worked 316L(2%) is twice that of the fully annealed material.