热轧酸洗板氧化铁皮缺陷原因分析及控制措施

针对热轧表检仪不能有效识别的片状、条状、山水画状、边部粗糙酸洗氧化铁皮缺陷,介绍了其形貌特征,对热轧工艺中的影响因素进行了分析和排查,得到了缺陷的形成原因。回炉板坯重复入炉加热,氧化铁皮的生成量将会增加,容易造成酸洗后片状氧化铁皮缺陷。除鳞水压力、喷射角度、喷射面重叠量及除鳞道次对二次氧化铁皮破除能力不足时,容易产生酸洗后条状、山水画状氧化铁皮缺陷。同时,粗轧工作辊轧制公里数较长、中间坯温度过高也会对山水画状氧化铁皮缺陷有一定的影响。热轧带钢终轧或卷取温度较高,薄规格带钢板形较差时,会造成酸洗后带钢边部粗糙氧化铁皮缺陷。为此,对板坯加热工艺、粗轧及除鳞工艺、精轧及层冷工艺进行了优化,大大降低了酸洗板氧化铁皮缺陷的发生率,提高了产品表面质量。

Cause analysis and control measures of oxide scale defects of hot rolled and pickled sheet

Aiming at the flake,strip-shaped,landscape painting and rough edge oxide scale defects of strip after pickled,which cannot be effectively identified by the hot rolling gauge inspection instrument,the morphological characteristics of these kinds of defects were introduced,and the influencing factors in the hot rolling process were analyzed and checked.The causes of the these defects were found out.When the slab is repeatedly heated in the furnace,the generation of scale will increase,it is likely to cause the flaky scale defects after pickling.When the descaling water pressure,spraying angle,overlap amount of spraying surface and the number of descaling passes are insufficient for the removal of secondary oxide scale,it is easy to produce strip-shaped and landscape painting oxide scale defects after pickling.At the same time,the long rolling kilometers of roughing work rolls and the excessively high temperature of the intermediate billet will also have a certain effect on the defects of landscape painting oxide scale.When the finishing rolling and coiling temperatures are high,and the flatness is bad of thin gouge strip,it is easy to produce rough oxide scale defects on the edges of strip after pickling.Therefore,the slab heating process,roughing rolling and descaling process,finishing rolling and laminar cooling process have been optimized,which greatly reduces the incidence of scale defects of pickled sheets and improves the surface quality of the products.