CONTROLLING METHOD FOR STEEL MAKING WITH CONVERTER UTILIZING BLOWING AND OSCILLATING

• Main Author: TACHIBANA RINZOU
• Format: Patent
• Language: English
• Published: 21.05.1983
• Subjects: CHEMISTRY; METALLURGY; METALLURGY OF IRON; PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OFWROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS

PURPOSE:To control the content of P in the stage of blowing out easily and surely by measuring the change in the oscillations of the body or ancillary devices of a converter to be blown with an inert gas, CO2 or O2 from the bottom thereof. CONSTITUTION:For a trunion shaft on a supporting ring 2 of a top or bottom blown converter 1 to be blown with, for example, an inert gas, CO2 and O2, the oscillations of the furnace body are measured by using a differential transformer or the like 3 on the outer side of a supporting base 4. As shown in the figure, oscilltions are fairly large during desiliconization in the initial period of blowing, but upon ending of the desiliconization, the state of slag formation is improved temporarily and the oscillations decreases. With progression of decarburization, the amplitude increases, and at the end period of the blowing, the amplitude decreases sharply on account of a decrease in the effect of decarburization and the progression of slag-off. It is discriminated from a blowing model and the measurement of the contents of C that said decrease in the amplitude is different from the cause occuring in the decrease in the oxygen efficiency of decarburization. The converter is blown out by assuring the time top for dephosphorization blowing from the time when said amplitude (b) decreases lower than 30% the amplitude (a) in the peak period of decarburization until the blowing-out determined according to the target blowing-out concn. of P.