Abstract
Composition-based correlations to predict the relative sensitization resistance of AISI 304 and 316 stainless steel (SS) have been evaluated by comparison to a large data base. The best fit to experimental data was achieved using a slightly modified version of Cihal's elemental parameters: Cr*=Cr+1.6 Mo−0.2 Ni−100 C where Cr* is the composite chromium concentration, and all concentrations are expressed as weight percentages (wt%). This composite chromium term effectively normalizes the effects of the major alloying elements on sensitization resistance. Attempts to add other alloying elements such as manganese, silicon, and nitrogen to the equation did not improve the correlation to the data base. Quantitative degree-of-sensitization (DOS) measurements were made on 14 heats of AISI 304 and 316 SS after various isothermal heat treatments using the electrochemical potentiokinetic reactivation (EPR) technique. Comparisons among these heats were found to be consistent with the proposed composite chromium formulism.
