Modeling and experimental calibration of the corrosion of RHA steel in immersion and salt-fog environments

An investigation into the general and pitting corrosion rates of rolled homogeneous armour (RHA) steel in immersion and salt-fog environments is presented. Although the mechanical properties of RHA steel have been studied, the corrosion effects on RHA steel have not been quantified. An immersion environment of 3.5% NaCl was used to induce corrosion for four immersion samples. A Q-fog corrosion tester was used to simulate a salt-fog/humidity/drying environment for four salt-fog samples. The different mechanisms of corrosion and their rates were quantified through mass loss, laser profilometry and scanning electron microscopy. The immersion samples show a linear rate of corrosion of 1.47 g/year (R2 = 0.994) throughout the entire testing period. The salt-fog samples had a significant mass gain for the first 500 h of corrosion, as the corrosion products are retained. Immersion samples showed no signs of pitting, while the salt-fog samples had sustained pit nucleation, growth, and coalescence.