Width change in roughing train of a hot strip mill is investigated.Formulas by which width spread in vertical and horizontal rolling is predicted are derived according to a regression analysis using measured values on a production mill.A new mathematical model for edger set-up is developed using above mentioned formulas. A feature of the new model is that it is practicable to adjust the roll opening at each edger depending on a given distribution pattern of width reduction at each stand.The new set-up model has been applied to Kashima Steel Works, Sumitomo Metal Ind., Ltd. since March 1979. Compared with the accuracy obtained by the conventional set-up method, width accuracy has been much improved by the present new model.
For the automatic control of hot metal temperature, a new simplified mathematical model of blast furnace has been developed on the following assumptions : (1) The working volume in the furnace is divided into five horizontal zones. Only the specified materials and reactions are considered in each zone. (2) By taking material balance, the flow rates of solid and gas at each zone are determined so that the amount of the material existed in each zone remains constant. (3) Heat balance is applied to solid and gas in each zone, respectively, taking account of their average temperature. (4) The reaction rates are formulated as the functions of operational variables on the basis of their step response characteristics. The temperature of solid and gas at each zone can be predicted by the adjustment of parameters in the model using actual operational data. Since the predicted solid temperature at the fifth zone (tuyere level) agrees well with the actual hot metal temperature, the validity of the model has been proved. At Kokura No. 2 BF, Sumitomo Metal Industries, Ltd., the model is being used for the automatic control and contributes to the stable blast furnace operation.
SynopsisFundamental study on automatic gauge control (AGC) of reversing cold rolling mill was carried out. The study includes the method of evaluating performance of AGC system and designing a control system according to the results of the study.It was concluded that the response of AGC system depends on the dynamic characteristics of a reel motor current control in either case of controlling reel motor current or roll position. The AGC system controlling the reel motor current is better than the AGC system controlling the roll position even with a hydraulic screwdown system.A new AGC system controlling reel motor current and roll position has been developed based on the above results. This system has been applied to Sendzimir and 4-high reversing mills.
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