Influence of nanosized precipitate on the corrosion behavior of high-strength low-alloy steels: a review

Compared with the widely used plain carbon steels, high-strength low-alloy steels exhibit high tensile strength, excellent fatigue performance, good plasticity, and toughness, and have attracted considerable attention in recent years. In the strengthening and toughening of high-strength low-alloy steels, the addition of carbide-forming and nitride-forming elements (i.e., Nb, V, and Ti) promotes the formation of nanosized precipitates. Nanosized precipitate in high-strength low-alloy steels plays a significant role in the microstructure optimization, which could maintain the high mechanical properties and excellent corrosion resistance of the steel matrix. With the advancement of characterization techniques and simulation methods in the atomic scale over the past few decades, the effect of nanosized precipitate on the corrosion behavior of high-strength low-alloy steels has become increasingly clear. Based on the obtained achievements in China and abroad, the existing morphology of nanosized precipitate and its influence on hydrogen diffusion, uniform corrosion, stress corrosion cracking, and hydrogen-induced damage were reviewed systematically in this study. Results show that the influence of nanosized precipitates on the corrosion behavior of high-strength low-alloy steels depends on its size, quantity, and status of crystal deposition. The fine and (semi-)coherent precipitate in the steel matrix can significantly improve not only the corrosion resistance by refining the microstructure (including the substructure) but also the resistance to hydrogen-induced damage by acting as an irreversible hydrogen-trapping site and strongly restraining hydrogen diffusion. However, incoherent precipitates with a large size would deteriorate the corrosion resistance because of the loss of microstructure optimization. Finally, this study forecasts the influence of nanosized precipitate on fatigue corrosion of high-strength low-alloy steels, which has not been investigated in previous studies. The optimization of the corrosion resistance of high-strength low-alloy steels can be achieved by controlling the nanosized precipitates. Clarifying the influence of nanosized precipitate on corrosion behavior would contribute significantly to the development of high-quality high-strength low-alloy steels.