THERMAL STRESS EVOLUTION OF THE ROLL DURING ROLLING AND IDLING IN HOT STRIP ROLLING PROCESS

초록

This study examined a critical idling time for the roll to attain a target temperature prior to rolling the next strip in the hot strip rolling process. Thermoelastic finite element simulations were performed to compute the temperature evolution and resulting thermal stress variations of the roll during rolling and idling. The results showed that a circumferential compressive stress was generated in the roll during rolling. However, circumferential tensile stress on the roll surface was produced very shortly (about 0.76 s) and reached about 68 MPa around 28 s after the beginning of idling. The temperature distribution of the roll's 1.5-mm-thick outer layer was homogenized and reached a steady state approximately 28 s after the onset of idling. Hence, we may cut down the long idling time (90-120 s), generally adopted in a hot strip rolling process, to decrease (by 68.9-76.7%) the roll temperature elevated during rolling to a target temperature.

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