Abstract
Electrochemical hydrogen permeation measurements have been performed on pre-strained pipeline steel base metal and weld simulated heat affected zone specimens. The level of plastic pre-strain was 0-3%. The effective diffusion coefficient decreased with higher pre-strain. At higher pre-strain levels the effect of plastic deformation on hydrogen diffusion is dominating the influence of microstructure. Sub-surface hydrogen concentration was found to be unaffected by plastic strain. The calculated number of traps was clearly higher than results available for alpha ferrite in literature.