Hydrogen-enhanced oxidation of ferrite phase in stainless steel cladding and the contribution to stress corrosion cracking in deaerated high temperature water

[摘要] Oxide film properties and stress corrosion cracking (SCC) behaviour are investigated in the 308L stainless steel cladding layer with and without being H-charged in a deaerated high temperature water. Phase boundary (PB) has lower oxidation resistance than austenite and delta-ferrite matrix. A compact and high Cr content-bearing inner oxide layer improves the oxidation resistance of the delta-ferrite phase without H charging. H-induced PB penetration oxidation and grain boundary (GB) preferential oxidation are observed in H-charged specimen due to the PB and GB act as H trapping sites. Charged H decreases the oxidation resistance of delta-ferrite and austenite. delta-Ferrite acts as a path for H diffusing and H flux facilitates mass transport, resulting in the poor oxidation resistance of delta-ferrite. The mechanism underlying the effect of H on the oxidation behaviours of delta-ferrite and austenitic phases, as well as SCC performance, are discussed. (C) 2021 Published by Elsevier B.V.

[发布日期] 2021-12-15

[关键词] Stainless steel;Ferrite;Hydrogen;Oxidation;Stress corrosion cracking;High temperature water