Influence of cathodic polarization on stress corrosion cracking susceptibility of 35CrMo steel for high strength bolt in simulated deep-sea environment

The effect of cathodic polarization on stress corrosion cracking (SCC) of 35CrMo steel for high strength bolt in the simulated deep-sea environment has been studied. The results show that 35CrMo steel has a higher SCC sensitivity at open circuit potential in the simulated deep-sea environment than that in the shallow seawater. With potential negatively shifted to -750 mV, 35CrMo steel presents the lowest SCC sensitivity. And the SCC susceptibility is increased significantly with the further negative shift of potential because of the intensive hydrogen evolution. When the potential is below -950 mV, hydrogen embrittlement with hydrogen-enhanced-plasticity mediated decohesion should be the dominant SCC micro-mechanism.