Synergic effects of temperature and pressure on the hydrogen diffusion and dissolution behaviour of X80 pipeline steel

Gas-phase hydrogen permeation experiments were conducted on X80 steel at temperatures from-15 degrees C to 60 degrees C and hydrogen pressures of 1, 4, 8 MPa. Hydrogen trap densities were determined, and a method for calculating nonlinear hydrogen concentration distribution was established and verified. Results reveal different temperature dependencies for hydrogen concentrations at varying pressures. At 4 and 8 MPa, the hydrogen concentration increases with temperature, whereas at 1 MPa, it initially decreases before increasing. Additionally, the influences of hydrogen pressure, hydrogen trap binding energy, and hydrogen trap density on this trend are discussed.