Enhanced hydrogen induced stress corrosion cracking resistance of Ni-advanced weathering steel by Ni and Mn modification

The stress corrosion cracking (SCC) behavior of three kinds of Ni-advanced weathering steel and a common weathering steel are examined in a simulated harsh marine environment by X-ray diffraction, scanning electron microscopy, electron backscattered diffraction, transmission electron microscopy, electrochemical tests, and slow strain rate tensile tests under different applied potentials. The results show that the SCC susceptibility of all test steel is low at open circuit potential. However, the SCC sensitivity of the conventional weathering steel increases significantly at -1200 mV, while the Ni-advanced weathering steel exhibits good resistance to hydrogen embrittlement, which is attributed to the improved stacking fault energy, decrease of martensiteaustenite constituents and refined grain size caused by increase in Ni and Mn content.