A Numerical Study of Skid Marks on the Slabs in a Walking-Beam Type Slab Reheating Furnace

Abstract

Three-dimensional simulations are performed for the turbulent reactive flow and radiation heat transfer in a walking-beam type slab reheating furnace. The temperature nonuniformity of the slab, which causes skid marks later during the rolling process, is explored and its improvement is investigated by varying either the distance between two static beams or the height of the skid buttons. The numerical model built takes care of the true geometry and all components of a real furnace. The temperature distributions of the slab and the gas mixture are obtained through a coupled calculation. The investigation shows the skid mark is mainly caused by the radiation shielding effect of the walking-beam system and worsened by the cooling system. The skid mark above the static beam near the furnace wall is more serious than above the other static beam because of poor mixing of fuel and air, and thus less combustion there. To improve the skid mark, the static beams should be moved outward in the soaking zone and the height of the skid button should be increased.

The support of this work by the China Steel Corporation under the contract 96T6D0012E and by the National Science Council, Taiwan, under the contract NSC 95-2221-E-002-336-MY2, is gratefully acknowledged.