The Research Of AGC Control System On QIANGANG 2250mm Hot Finishing Mill

Comparing the market demand for hot-rolled coils to the production ability of it in China, the latter is much higher than the former. The performance, quality and cost of the product of an enterprise determine its competitiveness and survivability. In terms of product quality strip thickness is an important vital indicator. In order to achieve a high level of thickness accuracy of product, AGC (Automatic Gauge Control) system is used in 2250mm Hot Finishing Mill in Qian’an Iron and Steel Co. Ltd (QIANGANG). Since 2008, in QIANGANG 2250mm hot strip rolling line, for a long time the production had been affected by thickness deviation and instability of the product. It had seriously limited the competitive ability of products and cost reduction work of the enterprise.This thesis takes the AGC system, the core part of quality control in production of QIANGANG 2250mm product line, as its study object. On the base of consulting on a large number of domestic and foreign documents 、 summarizing technical data of the system, we made a lot of study to reveal characteristics of thickness control in hot-rolled production. In order to reduce the thickness deviation, improve the thickness precision and make the rolling process stable, we made analysis of HGC system, the core of the AGC system, in depth.In this thesis, we study the gauge control system of QIANGANG 2250mm hot rolled strip mill firstly, stability of the system, factors affecting the rigidity of the mill and the method of changing the rigidity were all analyzed in depth, we made necessary dynamic simulation study to some of them. It is more important that we give a series of control and compensation strategy of HGC control system is presented, on the base of being familiar with the characteristics of fast response speed and good rigidity etc.With the development of study in HGC control system, in this thesis, we give response speed optimization and improvement proposals on AGC affected by HGC. For stability of rolling process of the mill, the influence rules control measures and its compensation method of various factors is presented.By comparing the actual dynamic characteristic parameters of the finishing mill, rolling mill AGC system dynamic performance mainly depends on the system performance of HGC is verified. Comparative analysis the results of simulation of thickness control system step response by the actual system testing curve in PDA monitoring system verifies the accuracy of the HGC simulation.Using the analysis results in this thesis to the actual production practice, we solved many practical problems about the thickness deviation and instability of rolling mill.