Research on marine atmospheric corrosion behavior of carbon steel during Western Pacific voyage

In this study, the dynamic marine atmospheric corrosion behavior of Q235 carbon steel was investigated during 9 voyages from the Yellow Sea to the Western Pacific Ocean over a period of 24 months. Field-exposure tests and inductance probe corrosion monitoring measurement were used to analyze the corrosion kinetics of carbon steel. The average corrosion depth measured by the inductance probe corrosion monitoring techniques showed excellent agreement with the data obtained from weight loss tests, demonstrating its reliability for corrosion monitoring and prediction in marine atmospheric environments. The results revealed a two-stage evolution of the corrosion rate: rapidly increased during the initial 3 months of exposure, reaching a peak of 166.2 mu m/year; and then gradually decreased due to the formation of a stable protective rust layer composed of alpha-FeOOH, Fe2O3 and Fe3O4. Carbon steel exhibited both general corrosion and localized corrosion. The localized corrosion demonstrated a progressive deepening trend, primarily driven by the synergistic effects of environmental factors, including alternating temperature variations, high relative humidity, and elevated chloride deposition during the voyage. This work provides key corrosion data for the application of carbon steel in marine equipment and the development of protective technologies, while also offering fundamental insights into kinetic modeling of dynamic marine atmospheric corrosion processes.