Abstract
Hydrogen Embrittlement is detrimental for product quality and a reliable estimate and assessment of its effects is of utmost importance to optimize the degassing treatments at both liquid and solid state by saving time and energy. As far as fatigue behavior is concerned, hydrogen presence, if higher than critical concentration, triggers phenomena such as decrease in cohesion forces and increase in pressure due to its deposition in microcavities. Therefore, the Hydrogen Embrittlement contribution is compounded to stress intensification, causing material fracture at lower loads. In this work the contribution of HE to crack growth behaviour is assessed by determining the threshold stress intensity factor KIHE and the critical value KIC-H, related to the fracture opening mode I in presence of hydrogen. To this aim, a special experimental apparatus was developed by adapting a standard apparatus for fatigue tests, and experiments on several specimens were conducted to validate the proposed approach.