Fe-1.76(w/o) Mn steel was used for the study of the main reason of the depth change in hydrogen induced blistering origin. For this study, a model is proposed as follow: blistering which is a result of the local plastic deformation is taking place due to a modified triaxial stress state around a void in which hydrogen molecules generate gas pressure. Triaxial stress state can be modified by the external or residual stress component to generate the shear stress component which is in responsible for the plastic deformation.
For the verification of this hypothesis, specimen are cold rolled and tensioned to give compressive and tensile residual stress state in the specimens, respectively. It is observed that as the amount of the cold rolling increased the compressive residual stress raised and the depth of hydrogen induced crack was also deepened.
However those specimens which were tensioned believed to have almost same residual tensile stress regardless the amount of the tensile strain show that the depth of the crack origin did not change with the percent deformation except for the first small strain. These observed experimental results give a possible confirmation of the proposed hypothesis which is based on the pressure theory of hydrogen embrittlement.
