The impact of hydrogen on mechanical performance of carbon alloy plates detected by eddy current method

ABSTRACT Hydrogen diffuses in the material and accumulates in dislocations, holes, etc. which will lead to deterioration of the mechanical properties of the material and affect the health state of the structural parts of hydrogen service. In this paper, a characterisation method for the degradation degree of hydrogen-induced properties of materials based on eddy current response signal is proposed. Based on the semi-infinite planar source diffusion model and hydrogen permeation model, an improved hydrogen diffusion and distribution analysis model was established, and an early hydrogen damage eddy current detection model for multilayer conductive structure materials was constructed. The evolution of material properties under the action of hydrogen was analysed, and a linear relationship between hydrogen content and conductivity was obtained. The loss of elongation was selected as the damage index and the relationship between the eddy current response signal and hydrogen embrittlement performance index is established. Experiments verify that the eddy current response signal is sensitive to the performance index and increases with the intensification of hydrogen-induced performance degradation.