Method for controlling rolling plate shape of steel plate

Abstract

The invention relates to a method for controlling the rolling plate shape of a steel plate which is particularly the steel plate with the thickness of 14mm-25mm and with the yield strength larger than 5000MPa and belongs to the steel rolling field. The method for controlling the rolling plate shape of the steel plate comprises the following control steps that controlled rolling is adopted by the steel plate, the secondary temperature-holding thickness of the steel plate in the finish rolling stage is 2-3.5 times as much as the thickness of the finished steel plate, the appropriate number of times of finish rolling is set, and the absolute rolling reduction of the last two times of finish rolling of the steel plate is limited. According to the method, the problem of unevenness of the steel plate with the yield strength larger than 500 MPa and with the thickness between 14mm-25mm is solved and the unevenness of the steel plate is reduced to no more than 4mm / m from over 50mm / m in the prior art. The rate of the added cold leveling procedure, due to the fact that the unevenness exceeds the standard, of the steel plate is reduced to 3% from 95% in the prior art.

Description

technical field [0001] The invention relates to a rolling shape control method of a steel plate, in particular to a steel plate with a thickness of 14-25 mm and a yield strength higher than 500 MPa, and belongs to the field of steel rolling. Background technique [0002] The traditional shape control method mainly focuses on controlling the crown of the steel plate, mainly through changing the roll shape of the backup roll and the work roll to change the shape of the roll gap to achieve the purpose of changing the shape of the steel plate. In recent years, with the development of metallurgical materials science, the purity of molten steel has increased, emphasizing the purpose of improving the comprehensive mechanical properties of steel plates by refining grains. In order to fully refine the grains of the steel plate, the trace element Nb is added to the steel plate, especially the steel with a yield strength greater than 500MPa. The purpose of adding niobium is to enable t...

AI Technical Summary

Problems solved by technology

Since the last pass is an empty pass, and the empty passing speed is between 1 and 3 m / s, the speed is relatively slow and the passing time is long, and the temperature drop is relatively large for thinner steel plates. In order to ensure the cooling of the rolled steel plate As a result, the actual final rolling temperature of the steel plate, that is, the temperature of the last pass with a reduction, will increase, and the increase in the actual final rolling temperature is not conducive to improving the performance of the steel plate

In addition, this method is not suitable for wide and thick plate rolling mills that use automatic control systems. For rolling mills that use automatic steel rolling, the position of the steel plate confirmed by the control system is completely determined according to parameters such as roller table speed and rolling force. The slipping between the roller tables causes the actual running speed of the steel plate to be lower than the speed of the roller table, so the position of the steel plate calculated by the system based on the roller table speed does not match the actual position of the steel plate. However, the actual steel plate is still in the machine frame. Since the margin for setting the empty roll gap is very small, the operator often has no time to manually intervene, resulting in the pressing down of the screw and strip steel, which will cause equipment safety accidents; finally, due to the final There is no reduction in one pass, and it is impossible to completely eliminate the poor shape of the corrugated plate that occurs during the rolling process of thinner high-strength steel, which affects the flatness and appearance of the steel plate