CSP流程薄板坯及热轧板卷氧化皮组织演变

Oxide Scale Microstructure Evolution of Thin Slab and Strip Coil Hot Rolled by CSP

采用SEM和XRD方法对CSP冷轧冲压用钢薄板坯和热轧板氧化皮进行了研究。结果表明,覆盖在板坯表面的氧化皮对高温腐蚀有明显保护作用,均热前后Fe2O3∶Fe3O4∶FeO质量分数比值为5∶35∶60,新鲜基体腐蚀严重些,Fe2O3和Fe3O4质量分数分别增加到28%和64%。卷取后快冷钢的氧化皮以2层结构为主,Fe2O3∶Fe3O4∶FeO质量分数比值为6∶31∶63,缓冷钢的氧化皮中析出了弥散或薄片状的Fe相,Fe2O3∶Fe3O4∶FeO∶Fe质量分数比值为8∶73∶15∶4,二者厚度相差不大。卷取温度升高,缓冷钢中残余FeO明显减少,不利于酸洗。

The oxide scale on both thin slab and hot rolled strip for cold rolled steel has been studied by XRD and SEM. It was found that oxide scale prior to soaking can protect obviously thin slab from high temperature corrosion of oxidation gas. After soaking Fe2O3 ： Fe3O4 ： FeO is 5 ： 35 ： 60, content of Fe2O3 and Fe3O4 are 28% and 64%, respectively. Oxide scale of strip with quick cooling after coiling comprises mainly two layer structure and Fe2O3： Fe3O4 ： FeO is 6 ： 31 ： 63. For the strip with slow cooling, new dispersed or lamellate Fe phase precipi tates and Fe2O3： Fe3O4 ： FeO ： Fe is 8 ： 73 ： 15 ： 4. There is no distinct difference of thickness between two oxide scale. However, for those strip with slow cooling after coiling, content of remained FeO of oxide scale obviously decreases, which is unfavorable to pickling.