Study On Technology Of Flying Gauge Change And Thickness Control For Tandem Cold Mill

With the development of iron and steel technology, continuous rolling is widely used by the tandem cold mills unit in the modern times. FGC technology is the core of continuous rolling for tandem cold mill. It aims at controlling thickness precision of the strip during FGC and reducing the thickness disqualification length of strip’s head and tail to research on FGC. Then it is possible to reduce the cutting loss and increase rolling yield, which are the great economic benefits to the real industry.By taking the five stands tandem cold mill of Shanghai Baosteel as the main research object and taking thickness control during FGC as the core, the thesis study the thickness setting and thickness compensation technology, and achieve the goal of improving thickness precision during FGC. The main work of the thesis includes the following parts.The main research is carried out about the FGC control technology in tandem cold rolling. The basic principle and control method are analyzed and studied by taking the main parameters of FGC process as the beginning. As well as, a study is carried out which is about the mathematical model of related rolling parameters during FGC. The tension model during FGC is deduced and the setting model is studied. Considering the real situation in the field, the needed key technology in real FGC application is analyzed and studied.Mainly make the research on FGC thickness setting. Combining the BP NN and mathematical model, it sets the rolling force which is the main factor of affecting the thickness and establishes an intelligent model of higher precision for rolling force. Directing at the shortcomings of NN, a GSA algorithm is proposed which is combined GA and SA algorithm to optimize NN for a better result.Another research is mainly on thickness compensation during the FGC. The regulating variable setting values of roll gap is adaptively adjusted timely with adaptive method, in order to compensating thickness during FGC to improve thickness precision.The simulation experiment is carried out by using a great quantity of field data from Baosteel. Rolling force presetting precision is improved much more by the combination of BP network and mathematical model. After optimizing BP network with GSA algorithm, the precision is improved more and the goal of high precision rolling force setting is achieved. During FGC the thickness is compensated and the fluctuation is greatly reduced by adjusting the roll gap adjust volume with adaption method. In a word, it improves the thickness precision, and the quality requirements of the strip’s head and tail are met to use the thickness control technology of thickness setting and compensation during FGC.