Research On The Stable Technology Of Strip Conveying In The Heating Section Of Continuous Annealing Furnace

As an essential process for the metallurgical enterprise to produce the high quality cold-rolled sheet steel, annealing can improve the tensile and inflectional strength of steel,and it can improve the mechanical properties and surface quality of sheet steel,too. So far,the annealing control technology has developed this situation that technologies of heating, cooling and high speed and stable strip conveying have been the core of the modern annealing technology. To meet the high demand of users for cold-rolled strip steel,the annealing technology is developing to the direction of producing wider and thinner products and faster speed of strip conveying in the continuous annealing furnace.But buckling and deviation become an increasingly conspicuous problem during strip conveying.The background of this paper is mainly the heating section of continuous annealing furnace where the buckling and deviation of strip often happen. Taking into account the existing control system related to the buckling and deviation of strip,the research on the roll crown and strip tension have been studied in this paper for the stability of strip conveying in the heating section of continuous annealing furnace.Firstly, the affected variation of roll crown is gained,which is based on the analysis of the mechanism of heat transfering between the roll and strip when strip is conveyed in heating section.It playes a role in calculating the compensation of roll crown. The roll crown variation has been compensated by the rule that the amount of compensation is equal to the variation affected by the heat transferring between the roll and strip. According to the specific situation of the top and bottom roll roller room, the roll crown has been compensated by different programs of compensation respectively. So it can avoid the variation of roll crown affected by the heat transferring and contribute to the stability of strip conveying in heating section of furnace.The values of strip tension have been set after the compensation of roll crown by taking models.It is very important to set the accurate values of strip tension because there is no precise and unified method for setting the value of strip tension in heating section of continuous annealing furnace. The setting of tension is gained according to the limit tension model of strip buckling and the analysis of related mechanism.Due to the site conditions affecting the accuracy of the mechanism analysis, the application of BP neural network build the tension model by using the data from the field. However, the two tension models only reflect the general rule,and they don’t give the optimal tension value in heating section. According to the mechanism of tension in heating section, the tension optimization model is gained indirectly by building the optimization model of roll velocity in the heating section. The0-1integer programming optimal model of the roll velocity has been established with considering these systems which contain the’the buckling and deviation of strip’,’energy system’,’production efficiency’,’heat treatment of strip’. The optimized velocity of roll is gained by using genetic algorithm. So the value of strip tension can be indirectly achieved,and it is the optimized strip tension. The research in this paper provides related reference for the stability of strip conveying in heating section.