Fractal experiment on stress oriented hydrogen induced cracking of pipeline steel

In this paper, a fractal experiment of stress oriented hydrogen induced cracking was carried out on the steel 16MnR and steel 20 of the gathering pipeline network in a sour gas field to verify the correctness of the relevant theoretical models. In the experiment, double cantilever beam specimens of the two steels were prepared and then immersed in the H2S corrosion solutions with different volumetric molar concentrations. Finally, the fracture data was sampled for calculation and analysis. It is verified that the fracture morphology of pipeline steel hydrogen induced cracking has fractal characteristics, and the relationship between the stress intensity factor and the fractal dimension follows a logarithmic proportional trend. What's more, the hydrogen-induced cracking criterion model, the hydrogen-induced cracking fractal propagation rate model and the hydrogen-induced cracking fractal physical mechanism model are verified to be correct. The research results can provide a reference for the prediction of crack growth rate in hydrogen environment of the in-service pipelines.