CN-117305546-B - Smelting method for reducing LF refining power consumption

Abstract

The invention relates to the technical field of LF refining, in particular to a smelting method for reducing LF refining electricity consumption, which comprises the steps of adding refined slag into tapping of a primary refining furnace without lime, dividing the LF smelting temperature-rising process into two stages, selecting different power factors and configuring different voltage gears and currents in different stage time periods, respectively adding 50% lime in second and third time periods of a first stage, heating molten steel in the LF temperature-rising second stage by adopting the different power factors and configuring the different voltage gears and currents, and calculating the time for naturally cooling the molten steel to the temperature required by the end of LF temperature rising and the required temperature-rising time. According to the invention, the slag charge is controlled to be added in the tapping process so as to facilitate LF early start and rapid slag formation, the refining electrifying submerged arc heating is facilitated, the optimal electrifying mode is selected in the follow-up process, the heating with low energy consumption is rapid, and then the mode of naturally cooling down to the required temperature is adopted, so that the LF electrifying energy consumption is reduced while the smelting rhythm is satisfied, and the cost and efficiency of the whole steel flow are reduced.

Inventors

• QU ZHIDONG
• MENG XIAOLING
• YANG PU
• GUAN TING
• HE JIAJIA
• SHEN YAN
• XIE YOU
• WANG XIANGHONG
• LIN JUN

Assignees

• 中天钢铁集团有限公司
• 常州中天特钢有限公司

Dates

Publication Date

20260505

Application Date

20230928

Claims (6)

1. 1. The smelting method for reducing the LF refining power consumption is characterized by comprising the following steps of: firstly, tapping in a primary smelting furnace, adding refined slag, and not adding lime; step two, dividing the LF smelting temperature rising process into two stages, wherein the first stage comprises three time periods; the second step specifically comprises: LF smelting is carried out for 0-2 min, and power factor cos is selected =0.85, Heating molten steel in 270V voltage range and current 24KA, LF smelting for 2-4 min, adding lime in 50%, and selecting power factor cos =0.75, Continuously heating molten steel by matching with 270V voltage gear and current of 30KA, adding the rest 50% lime for use in LF smelting for 4-8 min, selecting power factor cos =0.75, And with 270V voltage gear and 30KA current, the temperature of the molten steel is continuously raised; thirdly, in the second stage of LF smelting temperature rise, calculating the time for naturally cooling the molten steel after the temperature rise is finished to the temperature required by the end of LF and the temperature rise time required by the second stage of LF temperature rise; the third step specifically comprises: LF smelting is carried out for 8 th minutes to measure the temperature T 1 =1547deg.C, and the power factor cos is selected by heating =0.75, And the temperature of the molten steel is continuously raised by matching with 344V voltage gear and current 37 KA.
2. 2. The smelting method for reducing LF refining power consumption according to claim 1, wherein the refining slag comprises 40% -50% CaO, 5% MgO, 35% Al 2 O 3 ：35%~45%、SiO 2 % and 1% FeO.
3. 3. The smelting method for reducing the power consumption of LF refining according to claim 1, wherein the primary refining furnace is a 120-ton converter, the LF is a 120-ton refining furnace, and 45 steel is produced by using a continuous casting machine.
4. 4. Smelting method for reducing power consumption in LF refining according to claim 1, characterized in that the lime amount is 500kg.
5. 5. The smelting method for reducing the power consumption of LF refining according to claim 1, wherein the time formula for naturally cooling molten steel to the temperature required for LF finishing after the temperature rise is as follows: t ́ ́= wherein a is the temperature rising rate, b is the temperature falling rate, T 1 is the measured temperature of molten steel after the first stage of LF smelting temperature rising is finished, The required temperature of molten steel after the first stage of LF smelting temperature rise is finished; the temperature rise time required for the second stage of temperature rise.
6. 6. The smelting method for reducing power consumption in LF refining according to claim 1, wherein the temperature rise time required for the second stage of temperature rise is expressed by the formula: t ́=t-t ́ ́-t 0 Wherein t is the total period of LF smelting, t 0 is the total time of the first stage of LF smelting temperature rise, and t ́ ́ is the time for naturally cooling molten steel after the temperature rise to the temperature required by the end of LF.

Description

Smelting method for reducing LF refining power consumption Technical Field The invention relates to the technical field of LF refining, in particular to a smelting method for reducing LF refining power consumption. Background The production process flow of most types of steel comprises an LF process, the LF refining time is long, the alloy consumption is large, and the electricity consumption in the refining process is relatively large in proportion of steelmaking cost, so that the LF refining electricity consumption is reduced, the energy consumption can be reduced by refining, the LF refining process flow is an important component for reducing the production cost, the electric power characteristic curve of an LF transformer is scientifically researched, and the optimization of tapping slag and the like becomes an important link for steelmaking energy conservation and synergy. The literature 'optimization of 120tLF power supply curve', which indicates that LF (ladle furnace) secondary refining is a key process for producing cold rolled low carbon steel by converter-LF-CSP flow, only emphasizes how to study the most efficient heating gear, ignores the influence of smelting rhythm and slag-making technology in the actual production process on LF power consumption, and further does not pay much attention to how to utilize the most efficient heating gear in the actual production process. The literature 'forecast and control of molten steel temperature in the refining process of an LF furnace' indicates that the whole LF heating zone is divided into a heating period and a heat preservation period. The report does not pay attention to the influence of the relation between the slag submerged arc effect in the slagging stage and the cooperation of the power supply gear, the slag submerged arc effect in the slagging stage is poor, the low gear is adopted to slowly heat up to wait for slagging and slagging, and the temperature rise stage can be started after completion, on the other hand, the power supply gear with higher energy consumption and lower heat efficiency is adopted in the heat preservation stage, so that the balance of temperature rise and temperature reduction of molten steel is ensured, and the energy consumption is high and the energy efficiency is low. Disclosure of Invention Aiming at the defects of the existing method, the invention controls the slag charge addition in the tapping process so as to facilitate LF early rapid slag formation, facilitate refining electrifying submerged arc heating, and subsequently adopts the mode of rapidly heating with low energy consumption and naturally cooling to the required temperature by selecting the optimal electrifying mode, thereby reducing LF electrifying energy consumption while meeting the smelting rhythm so as to realize cost reduction and synergy of the whole steel flow. The technical scheme adopted by the invention is that the smelting method for reducing the LF refining power consumption comprises the following steps: firstly, tapping in a primary smelting furnace, adding refined slag, and not adding lime; Further, the refining slag comprises 40% -50% of CaO, less than 5% of MgO, less than 5% of Al 2O3：35％～45％、SiO2% and less than 1% of FeO. Further, the primary smelting furnace tapping is to produce 45 steel for a 120 ton converter, a 120 ton refining furnace and a continuous casting machine. Further, the lime amount was 500kg. Step two, the LF smelting temperature rising process is divided into two stages, the first stage is divided into three time periods, different power factors are selected in different time periods, different voltage gears and different currents are configured, and 50% lime is added in the second time period and the third time period of the first stage respectively. Further, the second step specifically includes: The method comprises the steps of selecting a power factor cos phi=0.85 in 0-2 minutes of an LF smelting temperature rising first stage, matching with a 270V voltage gear and a current 24KA to heat molten steel, adding 50% lime consumption in the LF smelting for 2-4 minutes, selecting the power factor cos phi=0.75, matching with a 270V voltage gear and a current 30KA to continuously heat the molten steel, adding the rest 50% lime consumption in the LF smelting for 4-8 minutes, selecting the power factor cos phi=0.75, matching with the 270V voltage gear and the current 30KA to continuously heat the molten steel. Thirdly, in the second stage of LF smelting temperature rise, adopting different power factors, configuring different voltage gears and currents to heat the molten steel, and calculating the time from the end of the heat up of the molten steel to the temperature required by the end of LF natural cooling and the required temperature rise time; further, the third step specifically includes: The temperature T 1 =1547 ℃ is measured in 8 minutes, the power factor cos phi=0.75 is selected for heating, and the temperatur