| The technological production process is introduced, especially US Steel Group's technological process. The structures and functions of the preheating zone, heating zone, soaking zone, slow cooling zone and rapid cooling zone are described. The furnace is divided into several model zones according to each section's characteristic.The mathematical model is presented and the off-line simulations are carried out for a strip steel hot-dip galvanizing annealing furnace, which adopt US Steel Group's technological process. The model simulates temperature of strip steel, wall, radiant tube, thermocouple and so on. DDC (direct digital control) module is applied for the control of reheating furnace.View factors in radiant tube furnace are calculated and the formulations for quaternary total radiative exchange areas and furnace temperature are deduced. Based on above works, the steady-state model and dynamic model are proposed. Applying steady-state model, the temperature and heat supplying strategies are obtained and convective heat-transfer coefficient in the reheating and rapid cooling sections is calculated. Taking the steady results as the initial values the transient process is simulated, in which the thermal characteristics of furnace is obtained from the process of the scale change of strip steel.VB.net is used. The computer program can read different parameters from the file and the results can be written into designated file. Therefore it can simulate and control temperature fields with different initial conditions.
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