Study and redesign of high temperature batch annealing furnace for production of grain oriented electrical steel

Grain oriented electrical steel coils are batch annealed at 1200 degrees C to develop the magnetic properties of the strip, Temperature gradients are known to exist within the coils, which can affect the three important react ions occurring in the steel during annealing. These gradients result from t he anisotropic conduction properties of the coil and the application of fur nace heat. Heat is applied from the furnace to the coil in the radial direc tion. Studies of the conduction properties of an electrical steel coil have shown that the radial coefficient is similar to 20% of the axial coefficie nt. Computational fluid dynamics was employed to simulate a furnace redesig n, comprising increased axial heating and a larger coil size. The results s how that the annealing cycle time may be shortened and annealing conditions simultaneously improved. The difference between process requirements and p rocess performance can be significantly narrowed by use of the redesigned f urnace. I&S/1456.