冷轧板表面黄斑缺陷原因分析及预防

摘要

The causes of macular defect on cold rolled sheet are analyzed by scanning and process investigation.It is believed that there is much residual emulsion on the surface of acid chilled rolls;in the case of incomplete cleaning, residual emulsion is cracked in the furnace under the action of high temperature reducing gas, which forms carbon enrichment.At the same time, iron compounds are formed by a series of chemical reactions occured between the residual Cl-on the surface of strip after pickling and water in water-quenching tank of continuous annealing furnace, which leads to macular.The macular defect on cold rolled plate surface are eliminated through a series of measures such as reducing acid emulsion concentration, impraving the reflectivity and cleaning effect of chill rolls and controlling water quenching tank temperature.%通过扫描电镜及能谱分析、工艺调查等手段,分析了冷轧板黄斑缺陷形成的原因.认为酸轧冷硬卷表面乳化液残留较多,在清洗不彻底情况下,残存乳化液在高温还原性气体作用下在炉内裂解,形成碳元素富集;同时酸洗后残留在带钢表面的Cl-,在连退炉水淬槽与水发生一系列化学反应形成了铁的化合物,导致黄斑缺陷的产生.通过降低酸轧乳化液浓度,提高冷硬卷反射率和清洗效果,控制水淬槽水温等一系列措施,根除了冷轧板表面的黄斑缺陷.