利用不同冷却方式在SS400热轧带钢表面形成了不同结构的氧化皮,通过腐蚀形貌宏观观察、SEM、EDS、XRD、失重法、干湿周期浸润腐蚀加速实验和电化学方法对不同结构氧化皮的热轧带钢在NaHSO_3溶液中腐蚀行为进行了研究。研究表明,不同冷却方式下所制热轧带钢的氧化皮均主要由Fe_3O_4组成,另含有Fe_2O_3和Fe。随着冷却速度的减小,氧化皮中Fe_3O_4的含量增加,但未发现有FeO;随炉冷却所制热轧带钢的氧化皮较厚且均匀,并存在分层现象(外层为Fe_2O_3,内层为Fe_3O_4+Fe),在NaHSO_3溶液中耐蚀性最好;装罐冷却所制氧化皮较均匀平整,耐蚀性次之;自然空冷所制氧化皮存在着较多的缺陷,耐蚀性最差。
Different structures scales were formed on the surface of SS400 hot rolled strip with different cooling methods.Corrosion behaviors of hot rolled strip with different oxide scales were investigated in sodium bisulfite solution by SEM,EDS,XRD,accelerated cyclic wet-dry immersion corrosion test,polarization curves and electrochemical impedance spectroscopy(EIS).The results showed that three kinds of oxide scales prepared by different cooling methods mainly consisted of Fe_3O_4,as well as a spot of Fe_2O_3 and Fe.The content of Fe_3O_4 increased with cooling rate reducing,but FeO was not detected.Oxide scale prepared by furnace cooling on the strip consisted of the outer Fe_2O_3 layer and the inner Fe_3O_4+Fe layer,and its thickness was more thick and homogeneous than the rest scales.Oxide scale prepared by jar cooling was homogeneous,but that prepared by air cooling had a lot of defects.Corrosion resistance of strip prepared by furnace cooling was best in 0.01 mol/L sodium bisulfite solution,but that of strip prepared by air cooling was worst.