Fully coupled crystal plasticity and hydrogen diffusion modeling of X52 pipeline steel and weld microstructures

Hydrogen diffusion in polycrystalline pipeline steels is greatly influenced by both mechanical stress and local microstructure features, and leads to hydrogen embrittlement and detrimental impacts on performance. In this work, a multiscale modeling approach, expanded to 3D models, is developed to investigate the response of the X52 pipeline steel and its heat affected zones to hydrogen diffusion, mechanical stress, and microstructures. This approach uses a digital microstructure reconstruction, a crystal plasticity constitutive model, and a hydrogen diffusion model based on chemical potential to explore hydrogen-material interactions. The results successfully predict experimentally observed macro- and micro-scale trends for high-cycle and low-cycle fatigue behavior of pipeline steels.