Method for reducing rephosphorization amount in converter tapping process and after slagging

Abstract

The invention discloses a method for reducing the rephosphorization amount in the converter tapping process and after slagging, and relates to the technical field of converter steelmaking processes, and the method comprises the following steps: pouring out part of slag, shaking a converter to a zero position, adding lime with the mass of a1 into the converter according to the temperature condition, shaking the converter for tapping, and judging the result according to the tapping temperature and end point components, a slagging deoxidizing agent with the mass a2 is added into a steel ladle, a slagging deoxidizing agent with the mass a3 and lime powder with the mass a4 are added into molten steel according to the phosphorus content at the end point of the converter and whether the converter is subjected to slagging or not, and argon blowing-in flow parameters in a molten steel tank are adjusted; according to the method, the whole treatment process of reducing the rephosphorization amount is within the rocking furnace tapping and tapping period time, the converter smelting period and production procedures cannot be increased, lime and a slagging deoxidizing agent needed in the treatment process of the method are all common materials in the normal production process, the method can be suitable for a converter without adopting a sliding plate to stop slag, and the cost is low. And the application range is wider.

Description

technical field [0001] The invention relates to the technical field of converter steelmaking technology, in particular to a method for reducing the converter tapping process and the amount of phosphorus returned after slagging. Background technique [0002] Phosphorus in steel is a harmful element. High phosphorus content will cause "cold brittleness" of steel, reduce low-temperature plasticity and impact toughness of high-priced steel, and deteriorate the welding performance and cold bending performance of steel. Phosphorus reduces steel. The element of surface tension, with the increase of phosphorus content, the surface tension of molten steel decreases significantly, thereby reducing the crack resistance of steel; phosphorus has a high degree of segregation in continuous casting slabs, and the diffusion rate in iron solid melt Very small, segregation is difficult to eliminate, affecting the quality of steel; [0003] In the process of sample tapping at the end of conver...

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Problems solved by technology

[0004] Chinese patent document 201110336040.X discloses a process of deep dephosphorization of molten steel by spraying powder on the ladle outside the furnace. The method provided by this patent is essentially a process of spraying dephosphorization powder in the ladle to dephosphorize molten steel in the ladle. It is suitable for For the production of ultra-low phosphorus steel (finished product phosphorus content ≤ 0.008%), special powder spraying stations need to be added during the production process, and special dephosphorization powder D (calcium silicon powder) needs to be sprayed in the ladle, and the molten steel needs to be transferred after dephosphorization treatment Go to the slag removal station for slag removal treatment. This treatment method is equivalent to adding a process between the converter and refining. The disadvantage is that if the above process is used when producing low-phosphorus steel grades with a phosphorus content of ≥0.008% in the finished product, One is that the temperature drop in the whole treatment process is large; the other is that the transfer time of the steel ladle is increased, which has a great impact on the production rhythm; Slag removal after phosphorus treatment will inevitably lead to an increase in the consumption of steel materials in the entire production process;

[0006] Patent 202010291260.4 discloses a control method for reducing the amount of phosphorus returned in the tapping process of low-phosphorus steel produced by a dephosphorization furnace, which includes the following steps: 1) After the end of the converter, the carbon is drawn, and the sub-lance is used to quickly measure the temperature and take samples. After the sampling is completed, the use of nitrogen is prohibited. Press the slag, shake the furnace directly on the slag surface, and pour out part of the phosphorus-rich slag; 2) After pouring the phosphorus-rich slag, shake the converter to zero, and add lime and sinter to the furnace; Meet the tapping requirements, start shaking furnace tapping; 4) During the tapping process, add graphite carbon powder to the ladle for pre-deoxidation; 5) After the pre-deoxidation is completed, add synthetic slag; 6) After the synthetic slag is added, perform final deoxidation of molten steel , Alloying operation; 7) The sliding plate blocks the slag at the end point, and the slag in the tap hole is prohibited from being put into the ladle after the steel is put in. This method is suitable for the converter using the sliding plate to block the slag, but not for the converter using the slag blocking rod to block the slag.

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