2 1/4Cr-1Mo Steels for Coal Conversion Pressure Vessels

Pressure vessels for coal conversion processes are likely to be made of a 2 1/4 Cr-1Mo steel, covered by ASTM specification A387, class 2, grade 22. Under the projected operating conditions, degradation of the mechanical properties of the steel by temper embrittlement and hydrogen embrittlement is a major concern. The significance of these degradation mechanisms is reviewed here in the light of experimental results recently generated by EPRI projects and other results published in the literature.