Measurement and Modeling of Sensitization Development in Stainless Steels as a Function of Thermomechanical Processing

摘要

An analytical model has been developed for predicting thermomechanical effects on the development of grain boundary chromium depletion in austenitic stainless steel as a first step in predicting intergranular stress corrosion cracking susceptibility. Model development and validation is based on sensitization development analysis of over 30 Type 316 and 304 stainless steel heats. The data base included analysis of deformation effects on resultant sensitization development. Continuous cooling sensitization behavior is examined and modeled with and without strain. Gas tungsten arc girth pipe weldments are also characterized by experimental measurements of heat affected zone temperatures, strains and sensitization during/after each pass; pass by pass thermal histories are also predicted. The model is then used to assess pipe chemistry changes on chromium depletion changes.