A Study of Change of Carbon Oxygen Equilibrium in 250 t Converter of Mei Steel

In order to ensure and improve the effect of the end-point control of the double-blown converter in Mei Steel, based on the statistical analysis of the current status of the carbon oxygen equilibrium during the campaign in Mei Steel, the influencing factors of the carbon oxygen equilibrium under the weak agitation process were investigated. The results show that the furnace ages of 4^# and 5^# 250 t converters are respectively 8 859 and 7 974, and the carbon oxygen equilibrium is stable at 21×10^-4-26×10^-4 during the campaign, and the average carbon oxygen equilibriums of 4# and 5# converters are 23.1×10^-4 and 24.0×10^-4 respectively, the bottom blowing of converter is well-controlled, which basically solves the problem that bottom blowing effect is gradually worsen with the increase of service life. The end-point temperature of converter, the number of bottom blowing holes and the lance position have significant influence on the carbon oxygen equilibrium. With the increase of end-point temperature, the carbon oxygen equilibrium first increases and then remains unchanged. The carbon oxygen equilibrium increases by 0.6×10^-4-0.8×10^-4 every 10℃. When the end-point temperature is higher than 1 660℃, the carbon oxygen equilibrium is stable at about 25×10^-4. The carbon oxygen equilibrium increases gradually with the increase of plugging number of bottom blowing holes. When the plugging number of bottom blowing holes is more than 6, the carbon oxygen equilibrium increase by 3.5×10^-4-5.0×10^-4 for every 2 plugging holes of bottom blowing. When the plugging number of bottom blowing holes is less than 4, the carbon oxygen equilibrium changes smoothly with the increase of the plugging number of bottom blowing hole, ranging from 21×10^-4-22×10^-4. The position of converter carbon lance is 1.6-1.7 m, and the time of carbon drawing is more than 40 s, which is beneficial to the reduction of carbon oxygen equilibrium and total iron content in slag.