Algorithm of no-pull control in the continuous mill train

The paper provides results of analysis of tensions in the inter-stand gaps of the continuous sub-train of the 2,000 mm mill roughing train of OJSC Magnitogorsk Iron and Steel Works. It shows that the existing system of automated no-pull control does not fulfil modern requirements. Reasons of the roll product dimensional accuracy reduction at the gauge diversification have been defined. The main reason is presence of uncontrolled longitudinal forces in the strip between tandem stands. The study offers the algorithm of electric drive speed mode control based on the calculation of the static load moments for modes of the separate and simultaneous rolling. According to the algorithm, electric drive speed control is performed based on the results of comparing the calculated moments with the set reference values. Results of experimental studies of this algorithm at 2,000 mm mill are provided. Improvement of the tension control accuracy by the factor of 2-2.5 has been proved. The paper emphasizes advantages of the commercial introduction of the developed algorithm and lists main technical effects.