Method for quickly smelting special-shaped blanks in LF (ladle furnace)

Abstract

The invention discloses a method for quickly smelting a special-shaped blank in an LF (ladle furnace), which is characterized by comprising the following steps: 1) heating according to the tapping condition of a converter, and replenishing proper ferro-aluminum, aluminum particles, lime and bauxite for slagging and deoxidizing; (2) after heating for the first time, dipping slag for observation, supplementing aluminum particles for deoxidation in the stirring process according to the slag color to achieve the purpose of rapid slag formation, and then sampling; (3) continuously heating, raising the temperature and slagging, and adjusting the adding amount of lime according to the in-place S content and the slag viscosity; 4) dipping slag after the secondary heating is finished, and supplementing silicon-calcium-barium for deoxidation according to the color of the slag; and (5) after the slag is made, feeding and soft blowing are carried out. The invention aims to provide the method for quickly smelting the special-shaped blank in the LF furnace, and aims to achieve the effects of quickly slagging, removing S, floating inclusions and the like in a short time by optimizing a process control mode in the LF refining furnace. The quality of molten steel is guaranteed, and the casting machine can be prevented from flocculating flow and the like.

Description

Technical Field

[0001] The invention relates to the technical field of LF refining furnace technology, in particular to a method for rapid smelting of special-shaped billets in an LF furnace. Background Art

[0002] The high crack rate of shaped billets has always been a problem that troubles major steel mills across the country. In recent years, Baosteel has been affected by the high crack rate of shaped billets, resulting in the failure to improve production capacity and efficiency, so it has been studying how to achieve the goal of rapid smelting and slag formation in LF furnaces. In the actual production process, there are always situations such as late timing, difficulty in desulfurization, difficulty in slag formation, and unstable flocculent pouring of molten steel. In order to ensure that all parameters meet the requirements and smelt good molten steel in a limited time, a method for rapid smelting of shaped billets in LF furnaces is proposed. Summary of the invention

[0003] The purpose of the present invention is to provide a method for rapid smelting of profiled billets in an LF furnace, and the purpose is to achieve the effects of rapid slag formation, S removal, floating inclusions, etc. in a short time by optimizing the process control mode of the LF refining furnace, which can not only ensure the quality of molten steel but also prevent the occurrence of floccules in the casting machine.

[0004] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0005] The present invention provides a method for rapid smelting of profiled blanks in an LF furnace, comprising:

[0006] 1) Heat treatment according to the steel-making conditions of the converter and add appropriate amount of aluminum iron, aluminum particles, lime and bauxite for slag deoxidation;

[0007] 2) After the first heating, dip the slag in the water for observation. According to the slag color, add aluminum particles to deoxidize the slag during the stirring process to achieve the purpose of rapid slag formation, and then take samples;

[0008] 3) Continue heating and slagging, and adjust the amount of lime added according to the in-situ S content and slag viscosity; (if the in-situ S content is 0.020%-0.030%, 2kg / t of lime needs to be added, and if the in-situ S content is 0.010%-0.020%, 1kg / t of lime needs to be added.)

[0009] 4) After the secondary heating is completed, dip the slag first, and add silicon calcium barium deoxidation according to the slag color; (If the color is light gray, add 0.2kg / t silicon calcium barium deoxidation, and if the color is grayish white, add 0.1kg / t silicon calcium barium deoxidation.)

[0010] 5) After the slag is made, feed the silk and blow it softly.

[0011] Furthermore, the timing for observing the color of the slag is adjusted from after stirring to before stirring.

[0012] Furthermore, in the later stage, silicon calcium barium is used instead of aluminum particles for deoxidation, which can not only reduce aluminum deoxidation products, but also play the role of calcium treatment.

[0013] Furthermore, bauxite is used instead of fluorite balls to change the refined slag system to increase the Al2O3 content in the slag (the Al2O3 content is increased from about 8% to about 14%).

[0014] Furthermore, the principle of like dissolves like can be used to effectively adsorb aluminum deoxidation products, improve product quality and stabilize production operations.

[0015] Compared with the prior art, the beneficial technical effects of the present invention are:

[0016] 1) This method is easy to implement and can effectively reduce the crack rate and increase production capacity;

[0017] 2) This method requires key technologies, so it is easy to promote and implement, and can ensure the implementation effect;

[0018] 3) This method can be promoted and applied in other steel mills to achieve the effect of rapid smelting in LF furnace. DETAILED DESCRIPTION

[0019] A method for rapid smelting of profiled blanks in an LF furnace, comprising:

[0020] 1) Heat treatment according to the steel-making conditions of the converter and add appropriate amount of aluminum iron, aluminum particles, lime and bauxite for slag deoxidation;

[0021] 2) After the first heating, dip the slag in the water for observation. According to the slag color, add aluminum particles to deoxidize the slag during the stirring process to achieve the purpose of rapid slag formation, and then take samples;

[0022] 3) Continue heating and slag formation, and adjust the amount of lime added according to the in-situ S content and slag viscosity; if the in-situ S content is 0.020%-0.030%, 2kg / t of lime needs to be added, and if the in-situ S content is 0.010%-0.020%, 1kg / t of lime needs to be added.

[0023] 4) After the secondary heating is completed, dip the slag first and add silicon calcium barium deoxidation according to the slag color; if the color is light gray, add 0.2kg / t silicon calcium barium deoxidation, and if the color is grayish white, add 0.1kg / t silicon calcium barium deoxidation.

[0024] 5) After the slag is made, feed the silk and blow it softly.

[0025] Furthermore, the timing for observing the color of the slag is adjusted from after stirring to before stirring.

[0026] Furthermore, in the later stage, silicon calcium barium is used instead of aluminum particles for deoxidation, which can not only reduce aluminum deoxidation products, but also play the role of calcium treatment.

[0027] Furthermore, bauxite is used instead of fluorite balls to change the refined slag system to increase the Al2O3 content in the slag (the Al2O3 content is increased from about 8% to about 14%).

[0028] Furthermore, the principle of like dissolves like can be used to effectively adsorb aluminum deoxidation products, improve product quality and stabilize production operations.

[0029] Implementation case (5 new smelting methods were adopted in 2021, and the annual crack rate was reduced by 1.47% compared with 2020)

[0030] Case 1:

[0031] The crack rate of Baosteel's special-shaped billets was 2.42% in 2020 and 0.95% in January-December 2021, a decrease of 1.47% from 2020. From January to December 2021, the output of Q235B was 550,964.673 tons, the output of Q355B (V) was 344,231.971 tons, the price of heavy scrap steel was 3,037 yuan / ton (calculated based on the weighted average of ERP for the whole year of 2021), and the manufacturing cost price of billets was 3,973.09 yuan / ton (calculated based on the weighted average of ERP for the whole year of 2021).

[0032] Benefit calculation: reduction in the tonnage of cracked steel billets × (steel billet manufacturing cost - unit price of heavy scrap steel) = 895196.644 tons × 1.47% × (3973.09 yuan / ton - 3037 yuan / ton) = 12.3183 million yuan.

[0033] Case 1:

[0034] According to the comparison of special-shaped billet production capacity in 2020 and 2021, the current average production capacity can be increased by 31 tons per shift, and the annual output of steel billets can be increased by 22,320 tons.

[0035] Comparison results between the original operation method and the operation method of the present invention:

[0036]

[0037] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A method for rapid smelting of profiled blanks in an LF furnace, characterized in that: include: 1) Heat treatment according to the steel-making conditions of the converter and add appropriate amount of aluminum iron, aluminum particles, lime and bauxite for slag deoxidation; 2) After the first heating, dip the slag in the water for observation. According to the slag color, add aluminum particles to deoxidize the slag during the stirring process to achieve the purpose of rapid slag formation, and then take samples; 3) Continue heating and slag making, and adjust the amount of lime added according to the in-situ S content and slag viscosity; 4) After the secondary heating is completed, dip the slag first and add silicon calcium barium for deoxidation according to the slag color; 5) After the slag is made, feed the silk and blow it softly.

2. The method for rapid smelting of profiled blanks in an LF furnace according to claim 1, characterized in that: The timing for observing the color of slag is adjusted from after stirring to before stirring.

3. The method for rapid smelting of profiled blanks in an LF furnace according to claim 1, characterized in that: In the later stage, silicon calcium barium is used instead of aluminum particles for deoxidation, which can not only reduce aluminum deoxidation products, but also play the role of calcium treatment.

4. The method for rapid smelting of profiled blanks in an LF furnace according to claim 1, characterized in that: Using bauxite instead of fluorite balls to change the refined slag system increases the Al2O3 content in the slag.

5. The method for rapid smelting of profiled blanks in an LF furnace according to claim 4, characterized in that: The principle of like dissolves like can be used to effectively adsorb aluminum deoxidation products, improve product quality and stabilize production operations.

6. The method for rapid smelting of profiled blanks in an LF furnace according to claim 1, characterized in that: In the above 3), when the in-situ S content is between 0.020% and 0.030%, 2kg / t of lime needs to be added, and when the in-situ S content is between 0.010% and 0.020%, 1kg / t of lime needs to be added.

7. The method for rapid smelting of profiled blanks in an LF furnace according to claim 1, characterized in that: In the above 4), if the color is light gray, 0.2 kg / t of silicon calcium barium deoxidation needs to be added, and if the color is grayish white, 0.1 kg / t of silicon calcium barium deoxidation needs to be added.

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