连退板表面白线缺陷成因和控制措施

针对首钢连退板表面白线缺陷问题，能谱分析发现白线缺陷内为海绵铁颗粒，且截面观察发现缺陷存在一定的压入深度，得出该缺陷是热轧卷表面的氧化铁皮压入所致。通过应用在线表检系统对问题卷表面进行反查，发现白线缺陷的热轧卷表面主要有3种类型氧化铁皮缺陷形貌，即条带状铁皮缺陷、西瓜皮状铁皮形貌、热轧机架共振造成轧辊氧化膜脱落形成的麻点形貌。针对此情况，对热轧工艺、轧辊氧化膜控制方法及热轧除鳞系统提出了优化措施，降低了连退板白线缺陷的产生。

Analysis of the formation reasons and control measures of white line defect on continuous annealing strip

In view of white line defect problem of continuous annealing strip at Shougang, the white line defect mainly composed of sponge iron particle by energy spectrum analysis and the pressed depth of defect were observed. So, its main reason was scale indentation. Through the history record of surface quality detection system, three kinds of scale morphology could be found on the hot rolled strip surface, which were banded scale, watermelon peel like scale, pock defect induced by oxide film dropping of roll. Therefore, the optimization measures about hot rolling temperature parameters, oxide film of mill roll control and descaling system were proposed , and good effects were obtained.