2D modelling of the effect of grain size on hydrogen diffusion in X70 steel

► Diffusion in grains and boundaries was modelled using Cellular Automaton technique. ► The technique is combined with the finite difference method. ► The simulation was implemented in two dimensions in grains and grain boundaries. ► The grain size has a two-fold influence on the diffusion rate. ► Diffusion rate in fine or coarse microstructures are lower than medium grain size.