Speaker
Description
Efficient control of heat transfer during hot rolling is essential for both product quality and rolls lifetime. This paper presents results from research on various descaling strategies and work-roll cooling.
Experimental investigations of various descaling systems—including conventional high-pressure nozzles, opposite-nozzle configurations, hydromechanical rotary descaling (HIDROD), and shot blasting—were conducted using laboratory heat-transfer measurements and real-scale trials. The results show that the descaling strategy significantly affects heat extraction, ranging from negligible heat loss with shot blasting to reductions exceeding 50% with optimized rotary systems.
Complementary laboratory measurements of roll cooling were performed to determine spatially resolved heat transfer coefficient (HTC) distributions under realistic spray conditions. It was demonstrated that HTC cannot be directly inferred from water distribution due to nozzle orientation and flow interactions, leading to substantial variations in cooling intensity along the roll circumference. These experimentally determined HTC fields were subsequently implemented into a thermo-mechanical model of the work roll.
Numerical simulations reveal that both descaling-induced heat losses and the roll-cooling strategy critically influence the thermal crown, temperature gradients, and the stress state in the roll. In particular, improper timing and positioning of cooling can increase maximum tensile stresses by more than 30%, significantly accelerating roll degradation. The results highlight that upstream descaling conditions modify the thermal input to the roll, while downstream cooling governs stress evolution.
The study demonstrates that integrated optimization of descaling and roll cooling provides a powerful pathway to reduce energy losses, improve surface quality, and extend roll service life, offering practical guidelines for modern hot rolling operations.
| Speaker Company/University | Heat Transfer and Fluid Flow Laboratory, Brno University of Technology, Faculty of Mechanical Engineering |
|---|