Process technology method for efficient and low-cost converter production of ultra-low phosphorus liquid steel

Abstract

The invention relates to a process technology method for efficient and low-cost converter production of ultra-low phosphorus liquid steel. According to the method, liquid steel with a temperature of 1260-1350 DEG C is added to a converter, wherein P content in the liquid steel is less than or equal to 0.11%, Si content in the liquid steel is 0.3-0.5%, and Mn content in the liquid steel is 0.3-0.6%; a slag material is added, argon gas is blown from the bottom, oxygen gas is blown from the top, and then the 1 / 3-1 / 2 of the slag is removed, wherein the flow rate of the argon gas is more than or equal to 0.07 Nm<3. / t.min, the pressure of the oxygen gas is less than or equal to 0.8 MPa, the bath temperature is less than or equal to 1450 DEG C, and the early stage converting time is 7-10 minutes; in the middle stage, a high lance position operation is adopted, the slag material is complementally added, and then 40-60% of the slag is removed, wherein the C content in the liquid steel is 0.30-0.60%, and the temperature is 1520-1560 DEG C; in the later stage, per ton of the steel is complementally added with 2-5 kg of lime and 2-5 kg of a cooling agent, a large amount of the argon gas is blown from the bottom, a stirring treatment is performed for more than or equal to 1.5 minutes, and the steel is discharged when the end point C content is 0.025-0.08% and the temperature is 1600-1630 DEG C. According to the present invention the ultra-low phosphorus liquid steel with the phosphorus content less than or equal to 50 ppm is produced.

Description

technical field [0001] The invention belongs to the field of metallurgical technology, and in particular provides a technical method for producing ultra-low phosphorus molten steel by a converter with high efficiency and low cost. Background technique [0002] The phosphorus content in steel affects various properties of steel, such as low-temperature toughness, etc. With the increasing requirements for material performance, the demand for ultra-low phosphorus steel is increasing, and the phosphorus content in steel is required to be ≤50 ppm (mass fraction, 10 -4 %). In order to produce ultra-low phosphorus steel, it is necessary to strictly control the phosphorus content in the steelmaking process. At present, there are two main modes for the production of ultra-low phosphorus steel in the converter steelmaking process. One is the single converter double slag method, but the molten iron is dephosphorized. Pretreatment, so that the phosphorus content of the molten iron ent...

AI Technical Summary

Problems solved by technology

These two process modes have certain disadvantages. The first method requires pre-dephosphorization of molten iron, which greatly increases the equipment and production costs of molten iron pretreatment, and the dephosphorization effect of the ordinary double-slag method is unstable. The slag does not fully meet the kinetic conditions of early dephosphorization, the dephosphorization effect is poor, and it is difficult to achieve a dephosphorization rate greater than 95%. Even if the molten iron entering the furnace is in good condition, it is difficult to stably produce molten steel with P≤50ppm; another The double converter method adds a special dephosphorization converter, increases equipment investment and operating costs, increases energy consumption, and the double converter is not easy to organize