Research On Head Warping Of Heavy Plate For A Steckel Mill

During the era of meager profit, improving the yield rate of the steel and reducing the cost of production are the keys to survive in the fierce competition for plate companies. The improvement of the head warping shape of the steel can significantly reduce the plate cutting loss in order to enhance the yield rate of the steel. This article relies on the project about the head warping shape of the heavy plate, which was carried out for the3500mm Steckel mill of a factory. Through the analysis of the original rolling process and the adjustment of the relevant methods, the head warping shape can be controlled. At the same time, according to the device characteristics and parameters of the thermal leveller, a reasonable leveling strategy is designed to improve the head warping shape. The main research contents and progress are as follows:(1) With the investigation on site, the multiple warping of the head of the plates was described, and the actual situation of the various factors that had an influence on the head warping shape of the plates during the rolling process were studied. At last, the main factors were pointed out. Besides, the thermal leveller was analyzed in order to make the reasonable leveling strategy.(2) The head warping theory of the plate was studied under the effect of the factors, which were the temperature distribution, the SKI coefficient, the height of the rolling line, the friction coefficient and the dynamic characteristics of the electric engine etc. The warping curvature formula was derived and the head warping law was pointed out.(3) The theory of leveling with static pressure was analyzed and the leveling strategy was developed. The multiple warping of the head of the high strength steel like X70, Q690etc. can be improved by leveling with static pressure for a time delay and then with the normal leveling process.(4) According to the head warping theory and the actual situation on site, the experimental program was designed, which consisted of the adjustment of the rolling line, the even-numbered pass plus the planishing pass rolling and the adjustment of the dynamic characteristics of the electric engine. After summarizing the results of the experiment, the optimal solution was obtained and successfully applied to the on-site mass production.