Effects of dissolved oxygen and flow velocity on corrosion of copper and carbon steel in flowing water

摘要

Effect of dissolved oxygen and flow velocity on corrosion of copper and carbon steel has been investigated in the deaerated water (dissolved oxygen concentration DO = 0.5, 2.0, 4.0 and 6.0 mg/l) and in the non-deaerated water (DO = 7.5mg/l) by using a flowing water corrosion test apparatus of loop type. The obtained results are as follows: (1) The corrosion rate of copper became the maximum value at the flow velocity of 1.0 m/s in the water of DO 2.0 and 4.0 mg/l. In the water of DO 7.5 mg/Lit became the minimum value at the flow velocity of 1.5 m/s. (2) The corrosion rate of carbon steel in the water of DO 0.5 mg/l increased with flow velocity. It became the maximum value at the flow velocity of 0.5 m/s in the water of DO 2.0 and 4.0mg/l. The corrosion rates of carbon steel in the water of DO 6.0 and 7.5 mg/l were larger at the flow velocity of 0.5 m/s, whereas they decreased with flow velocity. (3) The corrosion rates of copper and carbon steel became the maximum value in the oxygen supply amount of 4～8 (mg/l) · (m/s). They decreased over the oxygen supply amount owing to the passive film formation on metal surface.