Corrosion Resistance of a New Low-carbon High-strength Wear-resistant Cast Steel NMZ1

The corrosion behavior of a new wear-resistant cast marine steel NMZ1 with low carbon and high silicon was investigated in simulated sea-water by means of immersion test and corrosion-surface-morphology observation. The corrosion resistance had been evaluated by comparing the weight-loss with that of 20Cr5Cu for centrifugal pump impeller and Q345 for slurry pipeline. The results showed that sea-water corrosion resistance of NMZ1 was superior to that of Q345 but inferior to that of 20Cr5Cu. The corrosion rate of NMZ1 was 0.1215 mm/a in the 3.5% (wt) NaCl solution, which was about 2/3 of Q345 and 1.5 times of 20Cr5Cu. Alloying elements of NMZ1 could improve the protection of surface products and inhibit the occurrence of pitting, thus the alloy obtained a lower corrosion rate with uniform corrosion morphology.