SPHC热轧带钢酸洗表面发黑原因分析

柳钢生产的SPHC热轧带钢氧化铁皮难以酸洗清除,酸洗后板面出现了不同程度的发黑现象,影响了酸洗板表面质量。利用粗糙度仪、X射线衍射仪、扫描电镜、静态酸洗等多种试验分析方法,探究酸洗板发黑现象产生的原因。结果表明,柳钢生产的SPHC带钢残余元素Cu、Ni、Cr和As偏高,这些残余元素会富集于氧化铁皮下的基体金属中,增强氧化铁皮的黏附作用力,导致酸洗困难,残留的氧化铁皮会造成酸洗板表面偏黑。通过控制残余元素含量,酸洗后带钢表面色泽明显改善。

Cause analysis of surface blackening of SPHC hot rolled strip after pickling

The oxide scale of SPHC hot rolled strip produced by Liuzhou Iron and Steel Co.， Ltd. was difficult to be removed by pickling. Moreover， the surface of the plate appeared blackening in varying degrees after pickling， which affected the surface quality of pickling strip. The causes of blackening phenomenon of strip after pickling were explored by several testing and analysis methods， including roughness tester， X-ray diffractometer， scanning electron microscope and static pickling test. The results showed that the contents of residual Cu， Ni， Cr and As in SPHC strip produced by Liuzhou Iron and Steel Co.， Ltd. were high. These residual elements would be enriched in the matrix metal under the oxide scale， which enhanced the adhesion force of oxide scale， resulting in the difficulty of pickling. The residual oxide scale caused the surface blackening of strip after pickling. By controlling the content of residual elements， the surface color and luster of strip after pickling was obviously improved.