Abstract: Effects of the layerstructure oxide scale on the industrial atmosphere corrosion of hotrolled low carbon steels were investigated by wet/dry cyclic corrosion test. The corrosion weight gain， corrosion product structure and electrochemistry behavior of the specimens with the oxide scales were analyzed compared with that of the specimens without the oxide scales through scanning electron microscopy (SEM) and electrochemistry methods. It was found that the corrosion rate of the samples with oxide scale was lower than that of the naked steel. Polarization curves indicated that the samples covered with oxide scale had a lower corrosion potential than that of the naked steel. Single phase layered structure oxide scales had a good corrosion resistance that kept the substrate steel from corrosion. The integrity of oxide scale was the crucial prerequisite that the oxide scale protect the substrate steel. If the oxide scale was broken， galvanic corrosion will happen between the iron oxide and the substrate steel at the location of defects.

Key words: oxide scale, low carbon steel, industrial atmosphere corrosion, wet/dry cyclic corrosion test, local corrosion