某钢厂冷轧连续退火生产线在生产中发现用某型号平整液平整带钢后，带钢表面出现了黑色条带状脏污。针对这一缺陷问题，采用溶剂溶解试验、扫描电镜及能谱分析等方法分析了黑色脏污产生的原因。结果表明:该黑色条带状脏污是由退火残渣造成的。最后根据原因提出了相应的解决措施。

Black contamination was found on the strip steel surface after using a type of formation fluid in a steel mill’s cold rolling continue annealing line. Aiming at this problem, the solvent dissolution tests, scanning electron microscope and energy diffraction spectrometer were used to analyze the generation causes of the black contamination. The results show that the black contamination was caused by the annealing slag. Finally the countermeasures were proposed according to the causes.