The Optimization And Improvement On AGC Control System Of Qiangang2250Mm Hot Mill

When we compare the current market demand for hot-rolled coils and the production ability of it in China, we can draw the conclusion that the latter is much higher than the former. In this condition, the product performance, quality and the cost determine the competitiveness and survivability of the company.In all the qualities of hot-rolled coils, thickness is an important indicator. In order to achieve a high level of thickness control, we adopt the AGC, which is automatic gauge control in the finishing mill of2250mm hot strip mill in Qian’an Iron and Steel Co.,Ltd..In2011, we were obsessed with the thickness deviation and unstable rolling, which had serious impact on the competitiveness improvement and cost reduction..To reduce the thickness deviation, improve the thickness precision and make the rolling stable, we do a lot of work.First, this paper analyzes the control system of2250mm hot strip mill in Qian’an iron and steel Co.,Ltd. And it comes to the conclusion that AGC system is the control kernel of the strip thickness control. At the same time, it analyzes the basic control theory of AGC in hot rolling mill, the variable rigidity control of rolling mill, the control mode of thickness control, the hydraulic gap control of AGC system, mill zeroing, rigidity test of rolling mill and compensation control of AGC.Then, this paper analyses the AGC control system deeply. And it gives the ideas about how to solve the thickness deviation of strip tail, strip head and strip body and about how to make the rolling process stable. It describes the optimization methods of the AGC control of strip tail, the transformation of absolute AGC control and relative AGC control, the impact compensation of AGC. Also, it introduces the improving method of the rigidity of rolling mill and does analysis on its feasibility.At last, the above methods are applied in practice. And the problems of thickness deviation and unstable rolling are solved.