Induction furnace dephosphorizing method by top and bottom blowing

Abstract

The invention discloses an induction furnace dephosphorizing method by top and bottom blowing. The method includes the steps that loading and melting are performed; top blowing oxygen smelting is performed, and when the oxygen blowing is performed for 34-36% of whole oxygen supply time, the top blowing oxygen is stopped; slagging is performed; the top blowing oxygen is continuously performed; when the oxygen blowing is performed for 75% of the whole oxygen supply time, argon or nitrogen is started to be blown into the furnace from the bottom; when the smelting is performed to reach to liquid steel target carbon content range, the top blowing is finished; the bottom blowing intensity is enhanced; and conventional slag removal and deoxidation are performed, and tapping is performed to form billets. By means of the method, the dephosphorization and peroxidation contradictions caused by carbon-phosphorus reaction competition oxidation can be overcome, dephosphorizing load is reduced through slag removal at the low temperatrure, the molten bath peroxidation is restrained through inert gas top and bottom blowing, thereby the end liquid steel phosphorus content is reduced to 0.0050-0.0080wt. %, the dissolved oxygen content is lower than 0.060wt. %, the nitrogen content is lower than 0.0020wt. %, the steel clean degree is substantially improved, non-fluorite slagging is utilized in the smelting process to eliminate pollution of fluoride-containing slag to environment.

Description

technical field [0001] The invention relates to the control of impurities in metal smelting, in particular to an induction furnace dephosphorization method using top-bottom blowing. Background technique [0002] Oxide inclusions and phosphorus content in steel are very harmful to the quality and performance of steel. To overcome these defects, it is first necessary to reduce the oxygen content and phosphorus content in steel to the level required by users through steelmaking methods, and to suppress the molten pool synchronized with dephosphorization. peroxidation, reduce production cost. [0003] However, there is a competitive oxidation of carbon-phosphorus reaction in the steelmaking process, which makes the high-carbon area in the low-oxygen position unsuitable for deep dephosphorization; the target temperature of blowing low-carbon steel is not good for dephosphorization, and there is also molten pool overoxidation in the dephosphorization process , the high oxygen lev...

AI Technical Summary

Problems solved by technology

However, the disadvantage of this scheme is that it is difficult to dephosphorize high carbon in the early stage of smelting, the load of slag is large, and the slag is easy to rephosphorize and overoxidize in the later stage, which affects the cleanliness and yield of steel. Simply increasing the flow rate of bottom blowing gas also shortens the bottom blowing Component life issues