INTERACTION OF MICROSTRUCTURE, COMPOSITION, AND COLD WORK ON THE STRESS CORROSION CRACKING OF ALLOY 82 WELD METAL

摘要

Chromium concentration, weld-induced residual stress, and cold work are factors that affect the stress corrosion cracking (SCC) of both wrought Alloy 600 and Alloy 82 weld metal. However, chemical inhomogeneities and plastic strains that result from weld residual stresses that arise during solidification in welds makes it difficult to separate the beneficial influence of elevated chromium in Alloy 82 and the negative impact of weld-induced plastic strains. SCC growth rate tests on a single set of Alloy 82 weld cradles in four conditions were examined, including: as-welded, as-welded and cold worked, fully annealed, and fully annealed and cold worked. Annealing welds resulted in significant improvement in their SCC performance relative to the as-welded materials, but not significantly better than annealed Alloy 600 with similar chromium levels. This work shows that weld-induced plastic strains and cold work are similar and both are key drivers for the SCC performance for these materials.