Effects of Ce-La rare earth microalloying on the microstructure and corrosion characteristics of Q420 high-strength steel

In the present study, the effects of rare earth alloys on the corrosion resistance of Q420 high-strength steel have been studied by performing the neutral salt spray test and the electrochemical test. The influence rules for rare earth microalloying on the improvement of the corrosion resistance of Q420 high-strength steel, were then clarified. The results showed that the addition of rare earth elements will improve the corrosion resistance of Q420 steel. The corrosion resistance of the 2# and 3# steel was found to be better than that of the 1# and 4# steel. This was related to the effect of rare earth alloys on the shape and size of the inclusion. With a further increase in the content of rare earth elements,a large-sized inclusion appeareds in the steel. When the content of the rare earth element was 0.01%, the number and size of the inclusions in the Q420 steel were the smallest, and the corrosion resistance of the Q420 steel was the best. The corrosion resistance of the high-strength steel for transmission towers can thus be effectively enhanced by controlling the amount of rare earth element addition.