热镀锌汽车板表面小黑点缺陷研究及改进

Investigation and improvement of tiny spot defects on hot dip galvanized automotive steel sheet

使用SEM、EDS等试验手段研究了热镀锌汽车板表面小黑点缺陷的产生原因,并提出有效控制措施。研究表明:小黑点缺陷位置镀层局部偏厚,在镀锌后容易与顶辊产生摩擦,所以造成表面形貌与正常镀层有差异;锌渣、基板麻点和小翘皮三类缺陷容易造成镀锌后镀层局部偏厚,导致小黑点缺陷形成,通过对这三类缺陷的改善可有效控制小黑点缺陷的产生;其中,由于小翘皮缺陷的遗传性,需对其重点管控和监督。

The causes of tiny spot defects on the surface of hot-dip galvanized automotive steel sheet were studied by means of SEM and EDS,and effective control measures were put forward.Research shows,because tiny spot defect location plating is locally thick,it is easy to rub against the top roller after galvanizing,so the surface morphology is different from the normal part.Three kinds of defects such as zinc dross,small sliver and petting are likely to cause local thickening of the coating after galvanizing,causing formation of tiny spot.Therefore,improving these three types of defects can effectively control the generation of tiny spot defects.Among them,due to the hereditary nature of the defect of the small sliver,it is necessary to focus on its control and supervision.