Research of Acid Soil Corrosion Resistant New Steels for Grounding Grid

Abstract

The corrosion behavior of a commercial carbon steel Q235, and two new steels A1 and A2 in an artificial soil, which consisted of diatomite and appropriate acid solution to simulate a typical acidic soil at Southern China was studied by mean of corrosion weight loss measurement, and then the corrosion morphology and products were characterized by SEM and XRD. The results showed that the corrosion rate of Q235, A1 and A2 steel in the simulated acidic soil was 0.48, 0.14 and 0.097 mm/a respectively after 300 h corrosion; the tendency to micro-cell corrosion of a steel can be lowered as the carbon content of the steel has been reduced; an appropriate addition of Cr can shift positively the corrosion potential of the matrix; the enrichment of Cr in the inner portion of the rust scale can improve its compactness, and change the propagation mode of corrosion pits;the corrosion products of Q235, A1 and A2 steel were mainly consisted of α- Fe OOH, γ- Fe OOH and Fe3O4, however, the corrosion products of A1 and A2 steels possess a ratio of α-Fe OOH to γ-Fe OOH ca 10 times higher than that of Q235 steel, which implying a better protectiveness of the rust layers for the two new steels.