ABSTRACT
In the hot-rolling process, comparatively thin strips travel at high speed on the run-out table (ROT). The strip is run without tension during its threading and tailing out. Various defects-termed folded defect in head (Figure 13.1) and folded defect in middle (Figure 13.2)—caused by treading instability in this process have become a chronic problem. When a folded defect occurs in the head end or middle of a strip and is folded under by the coiler pinch roll, the affected part must be cut and discarded in the next process, which reduces product yield. If threading becomes extremely unstable, there are cases where the head end fails to reach the coiler, resulting in serious trouble and long downtime.
