Research On Deformation Mechanism Of The Cold Rolling Strip With Different Width-thickness Ratio

As the cold rolled strip becomes wider and thinner,the width-thickness ratio increases obviously,resulting in a sharp increase in the difficulty of flatness control and higher requirements of quality.In order to improve the flatness measurement and control index of cold rolled strip,it is very necessary to study the influence on the deformation mechanism of cold rolled strip with different width-thickness ratio.The thesis aims to study the influences of rolling parameters and control measures on the transverse distribution of rolling pressure,transverse displacement,elongation and edge thinning of cold rolled strip with different width-thickness ratio by physical experiments and simulation analysis.The relation between the deformation law and the flatness state of cold rolled strip is systematically summarized.Firstly,for the non-uniform deformation of cold rolled strip with different width-thickness ratio,the strip is lined with a laser marker.In order to reveal the deformation mechanism of cold rolled strip with different width-thickness ratio.The effects of compression rate,rolling force and deformation resistance on the strip elongation,lateral displacement and edge thinning are analyzed according to the experimental data.Secondly,the longitudinal residual stress of rolled strip is measured by X-ray stress meter.The corresponding law of elongation and longitudinal residual stress distribution in rolling of strip with different width-thickness ratio is analyzed.And the cascade relationship between lateral displacement and off-line flatness is analyzed by comparison.Then for cold rolled strip with large width-thickness ratio.The rolling process of six high reversing mill with different process parameters such as tension,friction coefficient and set value of control means is simulated.The influence mechanism of rolling pressure,lateral displacement and edge thinning of cold rolled strip with different width-thickness ratio was analyzed in order to find out the internal relation between stress state,deformation behavior and flatness state of cold rolled strip with large width-thickness ratio.Finally,the influence law of different control means,tension and friction coefficient on 1-4 flatness components is analyzed,which is based on the high order flatness problem of cold rolled strip with large width-thickness ratio.At the same time,the characteristics of flatness control and the complementary relationship of different control means are studied,which is helpful to analyze the coupling relationship between lateral displacement and the 4 flatness component.The above research provides an important reference for the research on the flatness measurement and control process of very thin cold rolled strip with large width-thickness ratio.It is not only conducive to know the physical deformation mechanism of cold rolled strip with different width-thickness ratio,but also able to implement a specific flatness control strategy for cold rolled strip with specific specifications.Therefore,the project has certain theoretical significance and engineering value for improving the flatness measurement and control effect of cold rolled strip.