Hydrogen Embrittlement Sensitivity of 10Ni5CrMo Steel at Different Temperatures and Polarization Potentials

The effects of temperature and polarization potential on hydrogen embrittlement sensitivity of 10Ni5CrMo steel in seawater environment were studied by electrochemical impedance spectroscopy, slow strain rate test and fracture morphology observation. The results show that at the same temperature, with the negative shift of polarization potential, charge transfer resistance decreased, fracture time, percentage elongation and percentage reduction of area after fracture decreased significantly, the hydrogen embrittlement coefficient (F) increased, and the hydrogen embrittlement sensitivity of the material increased significantly. When the polarization potential reached -1 000 mV (vs. SCE), F exceeded the maximum allowable value (25%) of the safety zone, which indicated that hydrogen embrittlement of the material would happen. At the same polarization potential, as the temperature increased, charge transfer resistance decreased, fracture time, percentage elongation and percentage reduction of area after fracture decreased, F increased, and hydrogen embrittlement sensitivity of the material increased. Compared with polarization potential, temperature had little effect on the hydrogen embrittlement sensitivity of 10Ni5CrMo steel at 4-25 ℃.