Corrosion behavior of stainless steels was investigated in nitric acid for the effect of cold work, sensitization heat treatment and is combination. Corrosion rate of solution-treated Type 304 with extra low carbon (304ELC) increased with time end reached constant values after 1000 h of immersion time. Constent corrosion rates, however, were obtained for 25 Cr-20Ni-Nb (310Nb) from the initial stage of immersion. Cold work mitigated corrosion of the solution-treated stainless steels. The effect of cold work was different on the two stainless steels wth sensitization heat treatment, showing accelerated corrosion for 304ELC. The corrosion resistance of 310Nb was superior to 304ELC after all the treatments. Chromium concentration of the sensitization treeaed 304 ELC was Iower in the grain-boundary region than that of the solution-treated one, although no chromium carbide precipitation was observed. This might be the cause of corrosion enhancement by sensitization treatment.
Keywords: reprocessing, stainless steel, nitric acid, sensitization, corrosion, cold work, dislocation, marlensite intergranuler corrosion, trans-passive corrosion, cold work, dislocation, martensite