Design of Heating Cycle in Hydrogen Annealing Furnaces

Abstract

Cold-rolled steel strips are annealed in batch annealing furnaces after coiling to release rolling residual stresses and to obtain desirable physical properties upon reaching recrystallization temperature. Simulation of coil behavior during heating cycle can be used to predict the temperature of coil middle points that cannot be measured directly so that furnace turn-off is properly scheduled. Using heat transfer equations and experimental data, a mathematical model of coil heating in hydrogen annealing furnaces was developed. This model is not only capable of predicting temperature distribution of all coil under various annealing conditions, but can also be used to design the heating cycles in a manner that all the constraints on temperature differences within coils are satisfied. Experiments confirmed the accuracy of the model in terms of its temperature predictive power and heating cycle scheduling capability.

Keywords:

• Annealing furnace
• Heating scheduling
• Steel strip coil
• Temperature prediction

ACKNOWLEDGMENT

The authors graciously acknowledge the funding of this project by MSC and would like to express their gratitude to the managers of the cold rolling mill and the R&D Department of Mobarakeh Steel Complex for their support.