热处理工艺对热轧带钢氧化皮结构及其耐蚀性的影响

Structure and corrosion resistance of oxide scale formed on hot rolled strip by different heat treatment processes

利用不同热处理工艺在热轧带钢表面形成不同组成与结构的氧化皮。采用SEM、XRD、LRS、干湿周期浸润腐蚀实验、EIS测试、开路电位测试对不同氧化皮热轧带钢在NaHSO3溶液中腐蚀行为进行了研究。研究表明,慢冷和炉冷所制热轧带钢氧化皮均由Fe2O3、Fe3O4、FeO和Fe组成,其中Fe2O3是微量的,前者含有更多的Fe3O4,后者含有更多的FeO。慢冷所制氧化皮致密、连续、厚度均匀;炉冷制备的氧化皮致密性较差,含有大量的缺陷。慢冷制备的氧化皮热轧带钢的耐蚀性要好于炉冷制备的热轧带钢的耐蚀性。

Different component and structure of scales were formed on the surface of hot rolled strip by different heat treatment processes.Corrosion behavior of the hot rolled strip with different oxide scales in sodium bisulfite solution were investigated by means of SEM,XRD,LRS,cyclic wet-dry immersion corrosion test,electrochemical impedance spectroscopy（EIS） and corrosion potential test.The results show that oxide scales prepared by different heat treatment processes mainly consist of Fe3O4/FeO/Fe,as well as a spot of Fe2O3.The relative content of Fe3O4 in the oxide scale prepared with slow cooling rate is higher than that in the oxide scale prepared by furnace cooling,while the relative content of FeO is lower.The scale prepared with slow cooling rate is dense,continuous and homogeneous in thickness,but the scale prepared by furnace cooling is less dense,with a lot of defects existing in the scale.The strip with scale formed at slow cooling rate exhibits more excellent corrosion resistance compared with that formed by furnace cooling.