BENEFITS, CHALLENGES AND LIMITS IN NEW ROUTES FOR HOT STRIP PRODUCTION

In this lecture several aspects of the new casting processes and of th e 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 r ate of shell growth and friction between strand and mold. Model comput ations show that the maximum casting rate for secure casting is in the range of 5 to 10m min(-1). In the new strip casting processes with tr aveling molds in which the friction problem does not arise the product ivity may be constrained by the general geometry of the casting machin e, With the twin-roll process there is the problem that the roll diame ters become unpractically large for high speed casting. There is no pr oductivity problem with the single-belt process, but there are other d ifficulties. Results are given on the control of thickness uniformity of the strand. If hot rolling is linked directly to the casting the ro lling speed must be slower than in the conventional process. Another c hallenge is hot rolling down to strip of 1 mm thickness or below. Theo retical data are presented for temperature loss and for scale growth i n non-conventional hot rolling. The models were used to compute the de velopments of temperature and of scale thickness in the integrated sin gle-belt casting/hot rolling lines.