Effect of Cr on the corrosion behavior of low carbon vanadium micro alloyed weathering steel in a simulated industrial atmosphere

Abstract

The study investigates the practical application of cyclic wet/dry corrosion tests in simulated industrial atmospheres to assess the impact of chromium (Cr) on the protective properties of vanadium micro-alloyed weathering steels. Two types of steels were examined: a V-N steel and a V-N-Cr micro-alloyed weathering steel. These steels were subjected to corrosion tests with 0.01 mol/L NaHSO₃ at a pH range of 4.4–4.8 for varying durations. The findings indicate that the inclusion of Cr in the composition of vanadium micro-alloyed weathering steel enhances corrosion resistance and leads to the accumulation of Cr in the inner rust layer. Furthermore, the distribution of corrosion-resistant elements (Cr, Ni, Cu, P, and Mo) in V-N and V-N-Cr steels is analyzed. The rust layer was observed to exhibit stratification in the corrosive environment, with the outer layers being dense and uniform, while the inner layers were porous and exhibited poor adhesion to the matrix. The study also delves into the anticorrosion mechanism of vanadium weathering steel using techniques such as X-ray diffractometer, electron probe microanalysis, and potential-phase diagram.