In the hot strip finishing mill, the range of the strip dimension has been widened as represented by rolling the high grade heavy line pipe material. On the other hand, the dimensional accuracy of the strip is also required to be further improved. Hence, the loopers in the finishing mill must have a large scaled mechanical frame to lift up the interstand heavy material. This scale up of the looper frame inevitably reduces its tension control performance especially for the light interstand material to disturb the product dimensional accuracy.
To cope with this problem, the authors developed full stand looperless tension control system for heavy material by adopting statistical processing scheme to estimate the rolling model parameters and realizing accurate tension measurement using rolling moter information. This was successfully applied to the hot strip mill (HSM) of Keihin Works, NKK.
This resulted in developping a new rolling method characterized in that the loopers are designed only for the use of light material to control fine tension to improve the dimensional accuracy of the HSM products.
