Benefite, Challenges and Limits in New Routes for Hot Strip Production
In this lecture several aspects of the new casting processes and of the linkage of casting with hot rolling into a combined in-line process is treated. A very important point is productivity. In a process with stationary mold the casting rate is limited by two phenomena, namely rate of shell growth and friction between strand and mold. Model computations show that the maximum casting rate for secure casting is in the range of 5 to 10 m min<sup>–1</sup>. In the new strip casting processes with traveling molds in which the friction problem does not arise the productivity may be constrained by the general geometry of the casting machine. With the twin-roll process there is the problem that the roll diameters become unpractically large for high speed casting. There is no productivity problem with the single-belt process, but there are other difficulties. Results are given on the control of thickness uniformity of the strand. If hot rolling is linked directly to the casting the rolling speed must be slower than in the conventional process. Another challenge is hot rolling down to strip of 1 mm thickness or below. Theoretical data are presented for temperature loss and for scale growth in non-conventional hot rolling. The models were used to compute the developments of temperature and of scale thickness in the integrated single-belt casting/hot rolling lines.
- ISIJ international
ISIJ international 38(8), 852-861, 1998-08-15
The Iron and Steel Institute of Japan