A Study on the Influence of Different Defect Types on the Corrosion Behavior of Q235/TA2 Composite Plates in a Marine Environment

The structural design of steel–titanium composite plates significantly affects their corrosion resistance. To investigate the impact of defects of different shapes and sizes on the corrosion behavior of steel–titanium composite plates, this study designed six types of defects and conducted a series of characterization tests. The results showed that due to the galvanic interaction between carbon steel and titanium alloy, small defects initially accelerate corrosion, resulting in 50% to 200% more corrosion weight loss compared to large defects. However, in the later stages of immersion, the corrosion rate of small defects decreased by up to 35%, which was attributed to the accumulation of protective corrosion products. Additionally, there is an inverse relationship between the corrosion rate and the thickness ratio of the composite plate. The reduction in the area of Q345B also results in additional corrosion loss of up to 32%.