Coiling temperature control and performance at AHMSA hot strip mill Mexico

To obtain high quality steel strip, rolling mill operators need to accurately control both the coiling temperature and also control the rate of cooling in the hot strip mill finishing process. This paper describes the special features of a coiling temperature control system which achieves these objectives. The system includes: a model reference adaptive control scheme; dynamic feedforward and feedback control strategies; along with a sample tracking system needed to accurately implement the control. The system responds well to changes in strip speed and finishing temperature. The control system is very robust and the impressive performance data included in this paper covers ALL coils rolled during a four month period of operation. The control system has the flexibility to allow adjustment of cooling rate through the use of spray patterns. Cooling rate is a key element in determining consistent metallurgical properties of the strip. This paper also highlights the data logging and draws a comparison between the design performance objectives and impressive actual performance achieved.