The corrosion resistance of ultra-low carbon bainitic steel

The corrosion resistance of ultra-low carbon bainitic (ULCB) steel was compared with a weathering steel 09CuPCrNi through accelerated corrosion tests. The results indicated that the corrosion resistance was almost the same for ULCB and 09CuPCrNi based on the weight loss. It can be seen that the grain refinement did not deteriorate corrosion resistance property. The homogeneous microstructure, lower carbon content and random distributing ∑3 boundary could effectively increase the corrosion resistance of the ULCB steel. The characteristics of the rust layers indicated that the inner rust layer contained nanocrystalline Fe3−xO4 particles, while copper and chromium alloying additions were enriched at the rust layer and substrate interface in ULCB steel. These factors played important roles in forming a compact protective rust layer.