Improvement of Electric and Mechanical System for Automated Strip Tension Control at Continuous Wide-Strip Hot-Rolling Mill

It is known that a modern trend in development of wide-strip hot-rolling mill technologies is gauge diversification owing to production of thin strip. Engineers are mastering methods of rolling 0.8−1.5 mm strip that was earlier manufactured at cold rolling mills only. Tension in inter-stand gaps of the continuous train is found to influence thin strip gauge greatly. Based on the example of the 2,500 mm mill at OJSC Magnitogorsk Iron and Steel Works, it has been proven that existing tension and loop size indirect control systems (TLSCSs) does not meet increasingly stringent requirements for accuracy of tension control. Here, improvement of control algorithms does not result in a significant quality rise. Thus, capabilities of the high-speed system for automated gauge control based on the Hydraulic Gap Control (HGC) may be useful. The improved TLSCS has been developed that enables control of the roll speed and HGC location of the previous stand. The system provides improvement of dynamic data due to compensation of the impact of the loop gear location of tension. Mathematical modeling has proven that the system developed ensures control of specific tension to a tolerance of ±10%. A dynamic component of the strip gauge deviation is within 3%. The TLSCS developed is recommended for implementation at 2,500 mm mill of OJSC Magnitogorsk Iron and Steel Works within the framework of the current reconstruction.