Publication Details

Haq, A. J., Muzaka, K., Dunne, D. P., Calka, A. & Pereloma, E. V. (2013). Effect of microstructure and composition on hydrogen permeation in X70 pipeline steels. International Journal of Hydrogen Energy, 38 (5), 2544-2556.


The influence of microstructure and composition on permeation of hydrogen in 1.2 and 0.5 wt.% Mn X70 pipeline steels after different processing was investigated using an electrochemical permeation technique. For 1.2 wt.% Mn (standard Mn) steel, the microstructure of normalised transfer bar was coarse equiaxed ferrite grains. This sample exhibited the highest diffusivity, followed by transfer bar, with a mixed ferriteebainitic ferrite microstructure; and hot rolled strip, with fine elongated ferrite grains. The 0.5 wt.% Mn (medium Mn) strip displayed lower diffusivity than the 1.2 wt.% Mn strip, due to hydrogen trapping by finer ferrite grains and a higher density of carbonitride precipitates. Moreover, the medium Mn strip exhibited a uniform microstructure and consequently similar diffusion coefficients for the edge and centreline regions, whereas the finer grains of the edge region of the standard Mn strip resulted in a lower diffusivity than the centreline region. Copyright © 2012, Hydrogen Energy Publications, LLC.

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