PURPOSE: To automatically and easily make the Si concn. of a continuously produced high-Si concn. steel strip coincide with a target Si concn. with high accuracy regardless of a fluctuation in the thickness of the steel strip.
CONSTITUTION: The thickness of the steel strip 1 on the inlet side of a siliconizing furnace 2 is measured online by a thickness gage 7. A calculator 8 calculates the thickness difference between the normal thickness of the steel strip 1 and the actually measured thickness by the thickness gage 7. The finish Si concn. of the steel strip 1 is calculated from this thickness difference and the concn. difference between this finish Si concn. and the target Si concn. is calculated. The correction rate of a siliconizing treatment gas is calculated in accordance with this concn. difference. The calculator 8 sends such an opening degree command as to make the corrected gas flow rate coincide with the actually measured flow rate by a flow rate detector 6 to a flow rate regulating valve 5.
HIROKAWA TAKASHI
YAMAJI TSUNEHIRO
