Furnace Atmosphere Modeling and Heat Pattern Design for Wire Coil Annealing Furnace for Specialty Steel

A wire coil annealing furnace for specialty steel is a furnace for annealing specialty steel wire rods by controlling the atmosphere and temperature in the furnace. When performing heat treatment, it is necessary to determine the heat pattern which is the reference of the furnace temperature and the concentrations of CO and CO2 in the furnace. However, the dynamics of the furnace atmosphere have yet to be modeled. Therefore, the response of the furnace atmosphere cannot be predicted and it takes a lot of time to determine the heat pattern. Conventionally, in heat treatment using simple gas, furnace atmosphere has been modeled by considering the movement of gas in furnace. However, when converted gas is used, the effects of the chemical reactions must also be considered, and this type of furnace atmosphere has not been modeled. In this study, we constructed the furnace atmosphere model that considers the effects of gas movement and chemical reactions in the furnace and developed the design system for heat pattern that can calculate the required flow rate of atmospheric gases during heat treatment. Finally, the effectiveness of the proposed system was demonstrated by comparing the design results with experimental results.