Pass Schedule Optimization for a Tandem Cold Mill
| Authors: | Murakami Akira, Kobe Steel, Ltd., Japan
Nakayama Makishi, Kobe Steel, Ltd., Japan
Okamoto Mitsuo, Kobe Steel, Ltd., Japan
Sano Kenichi, Kobe Steel, Ltd., Japan
Tsuchihashi Tomoya, Kobe Steel, Ltd., Japan
Abiko Yoji, Kobe Steel, Ltd., Japan |
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| Topic: | 6.2 Mining, Mineral & Metal Processing |
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| Session: | Rolling Mills II |
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| Keywords: | steel manufacture, control applications, optimization problems, robustness, multivariable control, linear quadratic regulators |
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Abstract
Pass schedules for a tandem cold mill affect not only the uniformity quality and productivity of rolled strips but also the operation safety. This paper describes pass schedule optimization, which consists of two stages. One is robust pass schedule optimization (RPSO) before rolling, which optimizes pass schedules under distributions in strips' properties and rolling conditions. The other is mill balance control (MBC) during rolling, which slowly changes the pass schedules to cope with remaining distributions and unpredictable during-rolling variations. Results with an actual mill showed an 8% decrease in off-gage length and a 2.4% increase in maximum rolling speed without deterioration in gage accuracy.
