Measurement of lattice and apparent diffusion coefficient of hydrogen in X65 and F22 pipeline steels

The permeation through and desorption of hydrogen from cathodically charged micro-alloyed API 5L X65 and low alloy ASTM A182 F22 steels were investigated with the aim to analyse the trapping parameters by means of the electrochemical method developed by Devanathan and Stachurski. The lattice diffusivity of hydrogen as well as the amounts and distribution of the diffusible and trapped hydrogen were found by means of partial permeation transient.

► Electrochemical hydrogen permeation in pipeline steels.
► Hydrogen diffusivity decreases along the curve when trapping becomes effective.
► Partial transient characterizes the lattice diffusivity of hydrogen.
► Density of trap sites and trapping binding energy were found by desorption technique.