Hydrogen behaviour in 34CrMo4 martensitic steels; Comportement de l'hydrogene dans les aciers martensitiques 34CrMo4

This study aims at a better understanding of the mechanisms of embrittlement, of the hydrogen-material interactions (diffusion, permeation, trapping) and of the hydrogen-plasticity interactions, and their consequences on hydrogen embrittlement in order to optimize steel microstructure. In the case of the 34CrMo4 martensitic steel, the study comprises a material elaboration and characterization, an investigation of hydrogen-microstructures interactions, an investigation of the influence of microstructure on material susceptibility to hydrogen embrittlement (by tensile tests on samples pre-hydrogenated or hydrogenated under mechanical solicitations), and the modelling of the role of microstructures in the damaging of martensitic steels by hydrogen. This paper reports the results obtained for the first three steps of this study