六西格玛视域下平整机斑迹类质量改进  

THE IMPROVEMENT OF SPOT QUALITY IN THE SIX SIGMA PERSPECTIVE

作　　者：张宝来 刘雪芹 Zhang Baolai;Liu Xueqin(School of Management,North China University of Science and Technology,Tangshan 063009,Hebei;Shougang Jingtang Iron and Steel United Co.,Ltd.,Tangshan 063009,Hebei)

机构地区：[1]华北理工大学管理学院,河北唐山063009 [2]首钢京唐钢铁联合有限责任公司,河北唐山063009

出　　处：《河北冶金》2023年第2期62-68,共7页Hebei Metallurgy

摘　　要：钢铁企业在工业大生产下,缺陷的处理往往通过定性分析制定改进措施,满足现阶段标准即可,而非达到最优效果。利用六西格玛管理理论研究了平整机斑迹类缺陷产生的原因及控制策略,发现镀锡产品平整机斑迹类缺陷形貌呈白色圆形或条形拖尾状,大小1~20 mm不等,分布在带钢上下表面整板面;微观分析显示缺陷处带钢表面纹路仍为轧辊轧制纹路,纹路表面未被破坏,成分主要为C、O(除去基体元素Fe)元素,C元素含量为51.2%,O元素含量8%,判定为油脂类有机物残留导致。通过因子思维导图、CE矩阵评估、FMEA失效分析和假设检验验证,锁定了平整液压力、平整液温度和支撑辊挡水板间隙为关键影响因子。并通过DOE实验和回归分析确定了平整液压力最优控制范围为3.7~5.0 bar,最佳控制点为4.4 bar;平整液温度的最优控制范围为42.0~45.6℃,最佳控制点为43.7℃;支撑辊挡水板间隙最优设定值为0.5 mm。改进后,平整机斑迹类质量缺陷降级量由147 t/月降至54 t/月。In the industrial production of iron and steel enterprises, the treatment of defects is often through qualitative analysis to develop improvement measures to meet the current standard, rather than to achieve the optimal effect. Based on the Six Sigma management theory, the causes and control strategies of spot defects of the mill were studied. It was found that the spot defects of the tin-coated mill were round or strip-tail, ranging in size from 1 mm to 20mm, and white, distributed on the upper and lower surfaces of the strip. Microscopic analysis shows that the strip surface pattern at the defect is still rolling pattern, and the surface of the pattern is not damaged. The main components are C and O elements(except the matrix element Fe), the content of C element is 51.2%, and the content of O element is 8%, which is determined to be caused by the residues of grease and organic matter. Through factor mind mapping, CE matrix evaluation, FMEA failure analysis and hypothesis testing, the key influencing factors were identified as the leveling fluid pressure, leveling fluid temperature and the gap between water baffle plates of the support roll. Through DOE experiment and regression analysis, the optimal control range of leveling fluid pressure is determined to be 3.7~5.0 bar, and the optimal control point is 4.4 bar. The optimal control range of the tempering liquid temperature is 42.0~45.6 ℃, and the optimal control point is 43.7 ℃. The optimal setting value of water baffle gap of support roll is 0.5 mm. After the improvement, the average degradation of spot quality defects of the whole machine decreased from 147 t to 54 t per month.

关 键 词：六西格玛 平整机 斑迹类缺陷 平整液压力 平整液温度 支撑辊 挡水板间隙 

分 类 号：TG335.21[金属学及工艺—金属压力加工]