Study of temperature effect on hydrogen embrittlement in X70 pipeline steel

The study investigates the temperature effect on hydrogen embrittlement (HE) in X70 steel using Devanathan-Stachurski and tensile tests under varying cathodic hydrogen-charging currents. The most severe HE temperature threshold is identified via scanning electron microscope (SEM) and electron backscatter diffraction (EBSD) methods. The temperature thresholds for 10 mA/cm2 and 20 mA/cm2 are 293 K and 283 K, respectively, while no critical temperature at 30 mA/cm2. The underlying mechanism is studied, and a predictive model is established. Also, the primary hydrogen-induced fracture plane is identified as {110}, beneath where hydrogen enhances plastic deformation in {110}<111> and inhibits in {112}<111>.