Disk Pressure Tests have been performed on polycrystalline Armco iron flat samples within a wide range of applied hydrogen pressure rise rates. The experimental overall response has been used to validate axisymmetric FE simulations of the test with isotropic elastic-plastic behavior. The distributions of the diffusive and trapped hydrogen concentrations in the zone of interest for HE show the effect of the applied pressure rise rate on the coupling between plastic strain and hydrogen transport. Moreover, submodelling in 3D synthetic polycrystals obeying crystal plasticity permits to exhibit statistically the effects of local heterogeneities on the hydrogen distribution and suggest local criteria for HE initiation. To go further on anisotropy analysis, preliminary results of full 3D simulations of bulging made on single crystals with various orientations are presented and discussed.