Role of microstructural degradation in the Heat-affected zone of 2.25Cr-1Mo steel weldments on subscale features during steam oxidation and their role in weld failures

摘要

Microstructural degradations in the base metaladjacent to the weld pool, i.e., the heat-affected zone (HAZ), causedduring welding of 2.25Cr-1Mo steel, were characterized by electronand optical microscopy of different regions of the weldments. Inorder to study the influence of the microstructural degradations onscaling kinetics in steam and the resulting subscale features, samplesof the base metal, the HAZ, and weld metal specimens were extractedfrom the weldment and oxidized in an environments of 35 pct steam+ nitrogen at 873 K for 10 hours.