Research On Reversible Single Stand 4-high Cold Rolling Mill Gauge Control System

The accuracy of strip gauge is one of two major quality control guidelines. It is especially important to increase the strip quality in the fierce competition of in and abroad market economy. The gauge control is the key technology in the field of strip rolling and it is developing fast in the recent years. Based on the 1270mm reversible single stand 4-high cold rolling mill gauge control system of some Iron and Steel Co. Ltd., the author studies the Smith predictor using in monitor AGC according to the large time delay in strip rolling. On the basis, a comprehensive gauge control strategy is developed and applied to field production. This paper main content:(1) On the basis of collecting and understanding literatures in and abroad, the author analyzes the basic theory of strip mill gauge control and several AGC composition methods and control modes of reversible single stand 4-high cold rolling mill.(2) Taking the 1270mm reversible single stand 4-high cold rolling mill gauge control system of some Iron and Steel Co. Ltd. as the research object, a computer control system which is based on the PLC and FM458 of SIEMENS is developed and the hydraulic gauge control system is studied.(3) The monitor AGC system of different controlled objects with Smith predictor is analyzed and simulated. Also the control rates are obtained with different regulators. Meanwhile, the relationship between the sample length of strip and time delay is provided and the Smith predictor is applied to the monitor AGC system successfully.(4) A comprehensive gauge control strategy including feed forward AGC with varying locking value, monitor AGC with Smith predictor using strip tracking, gauge meter AGC with mill spring mode, roll eccentricity compensation and gauge compensation during acceleration and deceleration is developed and applied to the 1270mm reversible single stand 4-high cold rolling mill gauge control system successfully. Field application shows that the gauge control strategy possesses advantages of nice practicability and portability.