TEMPERATURE CONTROL METHOD OF CONTINUOUS ANNEALING FURNACE FOR HIGH QUALITY ELECTRICAL STRIP MARKING

摘要

A temperature control method of a continuous annealing furnace for manufacturing of high quality electrical strip is provided to maintain an atmospheric temperature within the furnace within a stable temperature range of a fracture critical temperature or less according to type and size of a workpiece by cooling a tube and absorbing latent heat within the furnace, thereby emitting the latent heat to the outside of the furnace. A temperature control method of a continuous annealing furnace for manufacturing of high quality electrical strip comprises the steps of: performing a normal operation if the strip moves at a speed of not lower than a half of a normal speed, and performing a cooling control if the strip moves at a speed of not higher than the half of the normal speed by sensing a moving speed of a strip; cutting off combustion gas and improving output of an exhaust fan so that cooling air flows into the furnace when the cooling control is performed; increasing an inflow amount of cooling air if a temperature of the strip is higher than a normal temperature range of 740 to 760 deg.C and measuring a temperature of the furnace if the temperature of the strip is lower than the normal temperature range; increasing an inflow amount of cooling air if a temperature of the furnace is higher than a normal temperature range of 780 to 770 deg.C and measuring a temperature of a tube if the temperature of the furnace is lower than the normal temperature range; and maintaining temperatures of the strip, the furnace and the tube by increasing an inflow amount of cooling air if a temperature of the tube is higher than a normal temperature range of 780 to 800 deg.C and decreasing the inflow amount of cooling air if the temperature of the tube is lower than the normal temperature range.