THERMAL-ANALYSIS OF HYDROGEN-CHARGED AUSTENITIC AND DUPLEX STAINLESS-STEELS

Observations on the hydrogen trapping behaviour of 22Cr5Ni duplex aust enitic ferritic and AISI 304 austenitic stainless steels by a thermal analysis method are presented. After hydrogen cathodic charging at con stant current density, in the range 30-3000 min, the analyses were car ried out after a break period of 20 min and 1440 min, to remove in par t the diffusible hydrogen. Hydrogen trapping phenomena in steel with d ual phase structure and in fcc structure are related to different evol ution rate peaks of outgassed hydrogen. The effects of cathodic chargi ng on microstructure were observed metallographically.