Study On The Mechanism And Control Technology Of Edge Thinning During The Rolling Process Of Four Cold Mill

With the progress of technology and the improvement of living standard,the requirements of the strip’s quality and geometry has become more and more strict in steel industry,and edge drop of strip has great influence to the yield rate and shape accuracy of the strip steel.Therefore,how to analyze the formation mechanism of edge thinning,accurately calculate the thickness of strip and control technology have become an important research topic.This research has important theoretical value and practical significance to improve the yield and accuracy of the strip steel.Firstly,based on the previous researchers,a new concept of strip edge thinning region is defined,including the width of the edge thinning region and the maximum thickness reduction of the edge thinning region.The formation mechanism of edge thinning is analyzed,and two main factors are studied,which are metal’s lateral flow and roll’s elastic squash.A mixed modified elastic squash coefficient model is created,which is combined by two elastic squash coefficient models,then create a theoretical model which can calculate the thickness of strip steel.Then,based on the established theoretical model,the software of “four roll cold rolling mill’s edge thinning prediction” is developed.Quantitative analysis of the influence of the thickness of the inlet,the width of the inlet,the rate of rolling reduction,the shape of the roll and the roll shifting amount on the edge thinning area,which provide valuable technical guidance for the production site.Finally,two sets of optimization techniques are developed based on the edge thinning control:(1)The roll shape optimization technique with the aim of edge thinning control.Develop a set of roll shape optimization technology,and the application of the technology in a typical type of four roller cold mill shows the reliability of the optimization design by the analysis of the result;(2)The roll shifting optimization technique with the aim of edge thinning control.Develop a set of roll shifting optimization technology,and the application of the technology in a typical type of four roller cold mill shows the reliability of the optimization design by the analysis of the result.