Comparative study on the stress corrosion cracking of a new Ni-advanced high strength steel prepared by TMCP, direct quenching, and quenching & tempering

The stress corrosion cracking (SCC) behaviors of Ni-advanced steels prepared by thermo-mechanical control process (TMCP), direct quenching (DQ), and quenching & tempering (QT) are examined by microstructural characterization, electrochemical test, hydrogen permeation test, and slow strain rate tensile test under different applied potentials. The results show that the SCC susceptibility of these Ni-advanced steels is low at open circuit potential in the simulated environment, and the SCC mechanism is mainly controlled by the anodic dissolution process. However, the SCC sensitivity increases significantly at −1200 mV, and the SCC mechanism becomes hydrogen-induced cracking. The SCC sensitivity of the test steels decreases in the following order: TMCP steel > QT steel > DQ steel, which is primarily attributed to the microstructural difference.