Study On Optimization For Rare Earth Steel Strip Shape Of 2250mm Hot Rolled Mill

Baosteel's 2250 mm hot-rolled rare-earth steel sheet production line is imported from SMS,with a designed production capacity of 5 million tons per year.The product is positioned as a high-value-added elaborate sheet.The leading products are high-quality automotive sheets and household appliances.The featured products are high-strength.steel.The commissioning of this production line ended the history of high-end plate production in the west of China.This hot continuous rolling production line is of great significance to Baotou Steel.The 2250 mm hot continuous rolling mill is currently the widest rolling mill in China.Due to the increase in the length of the roll body,the mechanical behavior of the rolling mill is more complicated.In addition,the lack of sufficient experience in the production of rare earth steel makes the shape control problem particularly prominent.In the rolling process,various types of plates Shape defects frequently occur.In order to solve the problem of bad shape in the production process,this paper takes the rare earth steel rolling of 2250 mm hot-rolled unit of Baotou Steel as the research object,combining theoretical analysis,data statistics,numerical calculation,model simulation and industrial test,aiming at 2250 mm rolling mill plate for in-depth systematic research has been conducted on several aspects,such as the shape control characteristics,the control strategy of the bending shifting roll,the roll shape of the work roll and the back up roll,and the optimization of the wear prediction model.The specific work and results are as follows:Combined with the data of Baotou Steel's 2250 mm production line,ANSYS was used to establish a finite element model of the upstream and downstream mill roll systems in line with the actual production.Through the finite element model,the shape control capabilities of different control methods were analyzed to further grasp.The control characteristics of rolling mills laid the foundation for subsequent research and provided a theoretical basis for guiding industrial production.Statistics and analysis of the rolling process parameters from the site,quantification of the indicators for the adjustment of bending force and shifting roll crown,determination of the crown adjustment ability evaluation mechanism and judgment,to see whether the roll crown of each stand is reasonable,After analysis and calculation,it is found that the F1 stand crown control capability is insufficient,while the downstream stand crown control capability is kind of waste.(3)Analyze the matching characteristics of curved shifting rollers in the cyclic shifiting mode,derive the corresponding mathematical formula,and use this as the basis,combined with the analysis of the crown control ability to optimize the roll shape of the work rolls of each stand to achieve both crown control and the effect of uniform wear of the rolls;after determining the roll shape of the work roll,the roll shape of the back up roll is optimized for the purpose of uniform contact pressure between the rolls.(4)Using the traditional forecasting model to predict the wear roll shape of rare earth steel after rolling,it is found that the prediction accuracy is low,so the on-site roll wear data is analyzed to obtain the characteristics of the wear roll shape,the uneven wear function is improved,and the analysis of influencing factors for uneven wear simplify the function to obtain an improved roll wear prediction model,and its prediction accuracy has been significantly improved.(5)Both the optimized work roll and back up roll roll shape are now in stable industrial production and have achieved good application results.Among them,the shape defect rate has been reduced by nearly 30%,compared with the previous improvement,and the downstream stand roll consumption has been reduced 0.002 kg / t,and no roll peeling accident occurred.