Method of setting temperature of continuous heating furnace and method of controlling furnace temperature

A method of setting the temperature of a continuous heating furnace which heats a raw material loaded on a moving hearth using a burner and performs a reduction treatment, comprising the steps of:

• calculating a time function α=f(t) of a metallization rate α and a time function β=g(t) of a carbon content rate β of the raw material, using a furnace temperature T of the continuous heating furnace and an initial carbon content rate βIN of the raw material charged to the continuous heating furnace as parameters;
• dividing a space from a charging hole to a discharge hole of the continuous heating furnace into first to m-th zones (m is a natural number), assuming a furnace temperature Ti (i=1, . . . , m) for each of the zones, and forming a plurality of furnace temperature patterns including the furnace temperature T1 of the first zone to the furnace temperature Tm of the m-th zone;
• calculating a metallization rate α1OUT and a carbon content rate β1OUT at the exit of the first zone, using the metallization rate αIN of the raw material and the initial carbon content rate βIN of the raw material when the raw material is charged as a metallization rate α1IN and a carbon content rate β1IN at an entrance to the first zone, and the time functions α=f(t) and β=g(t) at the furnace temperature T1 of the first zone, and calculating a metallization rate αiOUT and a carbon content rate βiOUT at the exit of an i-th zone, using a metallization rate αi−1OUT and a carbon content rate βi−1OUT at the exit of an (i−1)-th zone (i=2, . . . , m) as a metallization rate αiIN and a carbon content rate βiIN at an entrance to the i-th zone, and the time functions α=f(t) and β=g(t) at the furnace temperature Ti of the i-th zone, thereby calculating the metallization rate αOUT at the discharge hole for each of the furnace temperature patterns;
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• calculating the necessary amounts of heat applied to the continuous heating furnace for the furnace temperature patterns in which the calculated metallization rate αOUT is greater than or equal to a target value, and setting the furnace temperature pattern among the calculated necessary amounts of heat applied which realizes the minimum necessary amount of heat applied as an optimal furnace temperature pattern.