FRACTURE TOUGHNESS CHARACTERIZATION OF HIGH STRENGH MARTENSITIC STEELS SUBJECTED TO HYDROGEN

High strength steels that are subjected to hydrogen may experience environmentally assisted degradation. These types of steels exhibit a loss of load bearing capacity. This paper presents a numerical-experimental method for screening materials’ susceptibility subjected to hydrogen. In this work it is found that hydrogen needs time to diffuse into the material and time to cause degradation. It is seen in this work that experimental fracture mechanics combined with cathodic polarization is an excellent choice to obtain reproducible results as well as a screening method of materials sensitivity to hydrogen embrittlement. An environmentally driven transition from high to low toughness was observed in a rather narrow range of loading rates. In this range, it was also observed that the hydrogen degradation may be mitigated by crack growth leaving less time for the degradation process to occur and a rise in toughness
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