| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for producing superclean steel by which the steel having high cleanliness can be effectively obtained by promoting coagulation flotation removal of inclusion in molten steel thereby shortening a refining time and improving the cleanliness of the steel. SOLUTION: The method for producing the superclean steel is performed in such a manner that in ladle refining for blowing gas into the molten steel from a tuyere disposed at the bottom part of a ladle, a gas flow rate is periodically changed and in such a case: differenceΔEcyc(J/t) in stirring energy densityεper one tuyere, per unit time and per unit weight of the molten steel between the values ofεat the maximum gas flow rate and the minimum gas flow rate is≥20, the stirring energy densityεbeing obtained by expression (1) ofε=(0.00618×Q×T/m)×[lnä1+(9.8×7000×h)/p}+(1-298/T)]; a period C(s) of change in the gas flow rate satisfies the relationship of 2≤ΔEcyc/C(W/t)≤5; and the stirring energyΣcyc(J/t) per one cycle of the change in the gas flow rate given to the molten steel as the integrated value of the difference of the stirring energy between at the minimum gas flow rate and at the maximum gas flow rate is 50-200. COPYRIGHT: (C)2011,JPO&INPIT |
