热轧钢氧化铁皮层对基体钢腐蚀动力学及电化学行为的影响

Effect of Oxide Scale Structure of Hot-rolled Steel on Corrosion Kinetics and Electrochemical Behavior of Matrix Steel

通过干湿交替加速腐蚀实验测定了带有4种结构氧化铁皮的实验钢的耐蚀性,测定了极化曲线,并根据极化曲线计算出氧化铁皮的孔隙率。研究结果表明:80周期腐蚀后,带有共析组织超过70%的氧化铁皮实验钢的腐蚀增重量最大,没有发生共析和先共析反应的氧化铁皮最小。带有4种结构氧化铁皮的实验钢的腐蚀动力学曲线具有相同的规律:腐蚀初期均符合直线规律,腐蚀中后期均符合抛物线规律。通过极化曲线测定出氧化铁皮的孔隙率,共析组织超过70%的氧化铁皮的孔隙率最大。带有氧化铁皮实验钢的腐蚀机理为电化学行为和氧化铁皮孔隙率综合作用的结果。

The corrosion behavior of hot-rolled steel with four types of oxide scale was investigated by the dry and wet cyclic accelerated corrosion test.By means of polarization curve measurements,the corrosion resistance and porosity of oxide scale were studied.The results showed that the oxide scale with over 70% eutectoid structure corrosion had maximum increment in weight,while the oxide scale without eutectoid or proeutectoid reaction had minimum increment in weight after 80 corrosion cycles.Corrosion kinetics curves of four types of oxide scale followed the same law：linear law at initial corrosion stage and parabolic law at middle and later corrosion stage.The model of corrosion kinetics was built by experimental data and the simulation results were closed to the practical corrosion data.Porosity was measured by polarization curve.The oxide scale with over 70% eutectoid structure had the maximum porosity.The corrosion mechanism resulted from the joint effects of electrochemical behavior and porosity of oxide scale.