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

The causes of tiny spot defects on the surface of hot-dip galvanized automotive steel sheets were studied using scanning electron microscopy(SEM)and energy dispersive spectrometer(EDS),and effective control measures were introduced.The results show that rubbing against the top roller after galvanizing is easy due to the local thickness of tiny spot defect location coating;therefore,the surface morphology is different from the normal part.Three kinds of defects,namely zinc slag,small slivers,and pitting,are likely to cause local thickening of the coating after galvanizing,leading to the formation of tiny spots.Therefore,resolving the three types of defects can effectively control the generation of tiny spot defects.Among them,due to the hereditary nature of the small sliver defect,focusing on its control and supervision is necessary.

应用直接控制图监控小批量毛条质量的方法

文章指出了传统统计过程质量监控工具、休哈特控制图的缺点,探讨了采用直接控制图对成品毛条条重指标的现场监控实践与具体方法,分析了直控图的优势,为小批量产品质量控制提供了一种新的途径。

热镀锌汽车板表面小黑点缺陷研究及改进

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。

异形曲面压力棒隔距块应用实践

针对如何能少投入、少设备改造、见效快地提高成纱品质,详细分析了异形曲面压力棒隔距块的曲面与浮游区的关系和改善成纱品质的作用机理。并通过与不同形式产品的对比试验,证明该产品的特性和积极效果;同时提出使用中的注意事项。