Combined effect of cathodic potential and sulfur species on calcareous deposition, hydrogen permeation, and hydrogen embrittlement of a low carbon bainite steel in artificial seawater

摘要

Calcareous deposition, hydrogen permeation, and hydrogen embrittlement of E690 steel in thiosulfate-containing artificial seawater (ASW) under cathodic polarization are investigated. Sulfur species in acidic ASW eliminate the aragonite precipitation, attributed to the variation of cathodic reaction, favorable adsorption of HS- and enhanced hydrogen evolution. The maximum permeation current was achieved at - 850 mV(SCE )due to the change of interfacial pH and promotion ability of sulfur species. Hydrogen embrittlement susceptibility increases linearly with logarithm increase of hydrogen concentration, while the preferential cracking pathway evolves from lath boundary separation at low hydrogen concentration to prior austenite grain boundary failure at high concentrations.