Production process for improving number of continuous casting furnaces of aluminum-containing titanium-containing plate blank molten steel

Abstract

The invention provides a production process for increasing the number of continuous casting furnaces of aluminum-containing and titanium-containing slab molten steel, and aims to solve the technical problems of nozzle clogging and low number of continuous casting furnaces of a tundish during continuous casting of the existing slab molten steel. According to the technology, in the converter steelmaking and tapping process, after deoxidizing is conducted through a deoxidizing agent and slag washing is conducted through a calcium slag washing agent, formed inclusions are rapidly removed under the argon stirring effect; then adding silicomanganese and a carburant for alloying, controlling the tapping amount of a converter, controlling the content of acid-soluble aluminum in molten steel entering an argon blowing station to meet the target requirement, enabling the molten steel to enter the argon blowing station, adopting a large-medium-small argon blowing mode during the period, uniformizing the components of the molten steel, adjusting the titanium content by using ferrotitanium, and removing a deoxidized product; small argon blowing is carried out for more than or equal to 10 minutes after calcification treatment; and finally, protective pouring is carried out during continuous casting. According to the technology, under the condition that high acid-soluble aluminum is obtained, molten steel is purified, the probability that a water gap is blocked by Al2O3 is reduced, the number of continuous casting furnaces of a tundish is increased to 60 or above from 10, and nodules are avoided in the whole continuous casting process.

Description

Technical Field

[0001] The invention relates to the technical field of metallurgical processes, and in particular to a production process for increasing the number of continuous casting furnaces for molten steel containing aluminum and titanium slabs. Background Art

[0002] Aluminum- and titanium-containing slab steel is aluminum-killed steel. To ensure good processing performance and strength, the acid-soluble aluminum is required to be ≥200ppm, and a certain amount of titanium is added for strengthening. The traditional production process is: converter smelting → argon station treatment → LF refining treatment → continuous casting and pouring. Among them, the converter smelting process: Since this type of steel belongs to low-silicon and low-carbon steel, the oxygen value of the molten steel is high, and a two-step method is required to control aluminum, that is, part of the aluminum deoxidizer is used for deoxidation during the steelmaking process, and the order of alloy addition is weak first and then strong, that is, silicon manganese and carburizer are added first, and then aluminum iron is added for deoxidation; Argon station treatment process: After the molten steel arrives at the argon station, sampling and analysis are carried out, and aluminum wire is added according to the acid-soluble aluminum content to make the acid-soluble aluminum in the molten steel reach a certain content. After the aluminum wire is added, the molten steel is hoisted out of the station to the LF refining furnace; LF refining process: During the refining process, the acid-soluble aluminum in the molten steel is adjusted through white slag refining, and aluminum particles are used to adjust the acid-soluble aluminum in the molten steel as a supplement for aluminum burnout, and titanium iron is added in the later stage of refining to regulate the titanium content in the molten steel. After the molten steel refining is completed, soft argon blowing should be performed for ≥5 minutes.

[0003] However, the production of aluminum- and titanium-containing steel using the traditional converter + refining process has the following problems: 1. Long production cycle: Refining treatment is adopted, and the refining cycle is extended by 40 minutes; 2. High processing cost: Refining treatment will increase the cost by 50 yuan / t steel; 3. Unstable production. The production process uses a large amount of aluminum, and aluminum is added in stages, which leads to incomplete floating of Al2O3 inclusions produced by deoxidation. During the continuous casting process, the nozzle floccules are serious. The number of continuous casting furnaces is low, reaching only 15 to 20 furnaces at most. The casting is forced to stop due to the serious nozzle floccules, resulting in unstable production and seriously affecting the quality of the steel billet. 4. Due to factors such as long production cycle and process burning, the acid-soluble aluminum content in molten steel is unstable. Summary of the invention

[0004] The purpose of the present invention is to solve the problems of long processing time, large amount of Al2O3 inclusions produced and difficult to float and remove, serious flocculent flow in the continuous casting process, low number of continuous casting furnaces in the middle ladle, long production cycle, high cost, etc. The present invention optimizes and adjusts the production process of aluminum- and titanium-containing slab steel, adopts one-step deoxidation + slag washing in converter steel tapping, direct continuous casting process, cancels LF refining outside the furnace, shortens the production cycle, reduces production costs, and increases the number of continuous casting furnaces in the middle ladle according to the mechanism of molten steel deoxidation and Al2O3 inclusion removal.

[0005] To achieve the above purpose, the technical solution adopted by the present invention is as follows: A production process for increasing the number of continuous casting furnaces for aluminum- and titanium-containing slab molten steel, wherein during the steelmaking and tapping process of a converter, firstly, a deoxidizer is used for deoxidation and a calcium slag detergent is used for slag washing, and then, under the stirring action of argon, the formed inclusions are quickly removed; then, silicon manganese and a carburizer are added for alloying, the steel tapping amount of the converter is controlled, and the acid-soluble aluminum content of the molten steel entering the argon blowing station is controlled to reach a target requirement, the molten steel enters the argon blowing station, during which a large-medium-small argon blowing mode is adopted to even out the composition of the molten steel, titanium content is adjusted using ferrotitanium, and deoxidation products are removed; then, after calcification treatment, a small argon blowing period of ≥10 minutes is performed; and finally, protective pouring is performed during continuous casting.

[0006] As the preferred technical solution: Optionally, the method specifically includes the following steps: Step 1: Converter steelmaking The converter is charged with molten iron, the requirements of which are: silicon = 0.10-0.80%, manganese ≤ 0.50%, phosphorus ≤ 0.250%, sulfur ≤ 0.015%, and the temperature is ≥ 1250°C for steelmaking. Then, the final composition of the converter is controlled to be: carbon = 0.05-0.15%, phosphorus ≤ 0.015%, and sulfur ≤ 0.015%; Step 2: Deoxidation slag washing According to the requirements of the final oxygen content and the acid-soluble aluminum content of the molten steel entering the station, during the steel-making process, a deoxidizer is first added to the molten steel for deoxidation, and then lime and slag washing agent are added for slag washing. A large amount of argon blowing is used for stirring at the bottom of the molten steel to make the generated Al2O3 inclusions combine with the slag washing agent to form low-melting-point inclusions, which are quickly removed from the molten steel; Step 3: Alloying Continue to add silicon manganese and carburizer for alloying, control the output of converter and the acid-soluble aluminum content of molten steel entering argon blowing station; Step 4: Argon blowing station After steel is tapped, the molten steel enters the argon blowing station. Depending on the tumbling of the molten steel, the argon pressure is adjusted to 0.2~0.5Mpa. The argon is blown for 2 minutes, with the molten steel surface tumbling but not violently blown. Then the argon blowing intensity is reduced and changed to medium argon blowing. At the same time, sampling and analysis are performed. Aluminum wire is used to adjust the acid-soluble aluminum content of the molten steel to a qualified level. Titanium iron is then added to adjust the titanium content of the molten steel. After the molten steel composition is adjusted to a qualified level, the argon blowing is changed to small argon blowing. Through this argon blowing mode, large particle inclusions in the molten steel can be quickly floated up and removed under the action of large volume stirring in the early stage. The medium argon blowing is changed to reduce the disturbance of the molten steel and the slag roll. Then the small argon blowing is changed to small argon blowing. Driven by small bubbles, the fine inclusions in the molten steel are further gathered and floated up for removal. Step 5: Calcification treatment According to the acid-soluble aluminum content in the molten steel, calcification treatment is carried out. First, medium argon blowing is carried out for 2-3 minutes, and then the CaFe line is fed for 200-300m. After completion, small argon blowing is carried out for ≥10 minutes, and the steel ladle composite insulation agent is added to the station. Among them, the purpose of controlling the time of medium argon blowing within this range is that the temperature drop is large if the time is too long, the cycle is extended, and the time is too short, which is not conducive to the uniformity of the composition; the purpose of controlling the time of small argon blowing within this range is that the temperature drop is large if the time is too long, the cycle is extended, and the time is too short, which is not conducive to the floating of inclusions; Step 6: Protective pouring The molten steel is poured into the tundish, and then poured into the crystallizer with a long nozzle for protection. Open pouring is prohibited. When pouring, the long nozzle of the large ladle is first put on, and then the slide plate is opened for pouring. A high-alkalinity covering agent is added to the molten steel surface of the tundish to prevent the molten steel in the tundish from being exposed and to avoid secondary oxidation of the molten steel during pouring. The gap between the tundish cover plate and the tundish is completely sealed with refractory fiber and fire mud. The plug rod hole and other holes on the cover plate are processed into corresponding regular hole shapes with aluminum silicate fiber felt and then tightly covered. Step 7: Continuous Casting Control During continuous casting, the shroud and lower shroud of the tundish are protected by argon sealing to ensure that the argon reaches the top of the shroud. During the casting process, the loss of acid-soluble aluminum is controlled within 0.010%, and the ratio of acid-soluble aluminum to total aluminum in the tundish is controlled to be ≥90%. Optionally, in the step 1, the converter uses a slide plate to block the slag, and the amount of slag discharged during steel tapping is strictly controlled, and the thickness of the slag layer is less than 50 mm.

[0007] Optionally, in step 2, the endpoint oxygen content is controlled at ≤900ppm, and the inlet acid-soluble aluminum content requirement is Als=0.035-0.050%, wherein the endpoint oxygen is controlled at ≤900ppm to reduce the amount of aluminum and iron used for deoxidation and reduce the generation of Al2O3 inclusions; The deoxidizer is aluminum iron, and the specific process step of the deoxidation is to add 200-400 kg of aluminum iron / furnace at one time when the steel tapping amount is 1 / 5 in the early stage of steel tapping. The deoxidizer of the present invention is not limited to this, and can also be steel core aluminum, etc. Other deoxidation agents that can achieve deoxidation and remove Al2O3 inclusions in molten steel are within the protection scope of the present invention; The amount of lime added is 150-200 kg / furnace, the slag washing agent is a special slag washing agent for CaO-Al2O3, and the amount of slag washing agent added is 50-70 kg / furnace. The specific steps of slag washing are: lime is added into molten steel from a high-level silo, and the slag washing agent is added into the molten steel manually at the same time, and the slag washing agent must be added after the aluminum and iron are added; The large argon blowing and stirring means that the flow rate of argon gas blown in can meet the requirement that the diameter of the exposed area of ​​molten steel is greater than 500mm; Among them, the amount of aluminum iron added is adjusted according to the oxygen content. The specific adjustment method is that when the oxygen content is 700~900ppm, 300~350kg / furnace of aluminum iron is used; when the oxygen content is 500~700ppm, 200~300kg / furnace of aluminum iron is used.

[0008] Optionally, in step three, the specific process steps of alloying are as follows: after the molten steel is deoxidized and the slag is washed, silicon manganese and a recarburizer are added successively when the tapping amount is 1 / 3, the silicon manganese added in an amount of 450-500 kg / furnace, the recarburizer is a 90 low-sulfur recarburizer, and its added amount is 80-100 kg / furnace; the converter tapping amount is controlled at 70 t / furnace, and the acid-soluble aluminum content of the molten steel at the argon blowing station is controlled at Als=0.035-0.050%.

[0009] Optionally, in the step 4, when the acid-soluble aluminum content meets the requirements, no aluminum wire is fed; when the acid-soluble aluminum content is low, aluminum wire is fed to fine-tune the acid-soluble aluminum, and the content is controlled to be 0.035%≤acid-soluble aluminum≤0.050%; the titanium iron is specifically 70 titanium iron, and the addition amount thereof is 80 kg / furnace.

[0010] Optionally, in step 4 and step 5, the large argon blowing refers to the argon flow rate blown in that can meet the requirement that the diameter of the exposed area of ​​the molten steel is greater than 500 mm, the medium argon blowing refers to the argon flow rate blown in that can meet the requirement that the diameter of the exposed area of ​​the molten steel is 300-500 mm; and the small argon blowing refers to the argon flow rate blown in that can meet the requirement that the diameter of the exposed area of ​​the molten steel is 200-300 mm.

[0011] Optionally, in step five, the ladle composite insulation does not need to contain a high silica content. After the CaFe wire is fed, the soft blowing time must be ensured to be more than 10 minutes before it goes on stage. The purpose of this is to cause small inclusions to gather and float under the soft blowing of argon, and to reduce the tumbling of molten steel and slag rolling.

[0012] Optionally, in step seven, the casting speed is 1.00-1.25 m / min, the specific water content is 0.8-0.9 L, the high basicity covering agent refers to CaO / SiO2 with a mass ratio of >2.0, and the addition amount is 50-80 kg / furnace.

[0013] Optionally, in the step seven, the loss of acid-soluble aluminum is controlled within 0.010% during the pouring process, and the ratio of acid-soluble aluminum in the tundish steel to total aluminum is controlled to be ≥90%. The control method is as follows: when the ladle is started to be poured, a long water nozzle is first installed, and then a slide plate is opened to prevent the molten steel from contacting with the air and oxidizing; then argon is blown into the tundish to prevent the molten steel from oxidizing; argon is sealed at the lower water nozzle of the tundish to prevent the molten steel from absorbing air and oxidizing, and under the full protection of the pouring, the oxidation amount of acid-soluble aluminum in the molten steel is controlled to be less than 0.010%, thereby increasing the effective acid-soluble aluminum content.

[0014] Invention mechanism: In the traditional process, due to the large amount of aluminum used, the Al2O3 inclusions generated by deoxidation are difficult to remove in a short time. In order to avoid the precipitation of Al2O3 and the blocking of the water outlet during continuous casting, LF refining outside the furnace is used to remove the Al2O3 inclusions in the molten steel, so as to achieve the purpose of purifying the molten steel. The present invention cancels the LF refining production process outside the furnace, and uses the process of first deoxidation and then slag washing before steel tapping, which is conducive to the argon blowing and stirring at the bottom of the molten steel. The oxygen in the molten steel can be completely removed in a very short time. The Al2O3 inclusions generated are combined with lime and CaO in the slag washing agent to generate low melting point compounds, and the molten steel is quickly discharged, which plays a role in efficiently purifying the molten steel. At the same time, through the control of the large-medium-small argon blowing mode of the argon station, the residual inclusions in the molten steel are further removed, and the continuous casting is fully protected to prevent the acid-soluble aluminum from oxidizing to generate Al2O3 to block the water outlet again.

[0015] Compared with the prior art, the present invention has the following beneficial effects: 1. The process of the present invention completely solves the problem of continuous casting pouring nozzle flocculent flow, the number of tundish continuous casting furnaces is increased from 10 to more than 60, there is no nodule in the whole continuous casting process, and the production is not interrupted.

[0016] 2. The acid-soluble aluminum content of the finished product in the whole process of the process of the present invention is stably controlled, reaching an average of 300ppm.

[0017] 3. The present invention cancels the LF refining production process outside the furnace, shortens the production cycle by 40 minutes, and reduces the production cost by 50 yuan / t. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 The present invention is a flow chart of the production process for increasing the number of continuous casting furnaces for molten steel containing aluminum and titanium slabs. DETAILED DESCRIPTION

[0020] In the following, only some exemplary embodiments are briefly described. As those skilled in the art will appreciate, the described embodiments may be modified in various ways without departing from the spirit or scope of the present invention. Therefore, the drawings and descriptions are considered to be exemplary and non-restrictive in nature.

[0021] The embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0022] The embodiment of the present invention provides a production process for increasing the number of continuous casting furnaces of molten steel containing aluminum and titanium slabs, such as Figure 1 As shown, the following steps are included: Step 1: Converter steelmaking The converter is loaded with molten iron, the requirements of which are: silicon = 0.10~0.80%, manganese ≤ 0.50%, phosphorus ≤ 0.250%, sulfur ≤ 0.015%, and the temperature ≥ 1250°C, for steelmaking. Then, the final composition of the converter is controlled to be: carbon = 0.05~0.15%, phosphorus ≤ 0.015%, and sulfur ≤ 0.015%. The converter uses a slide plate to block the slag, strictly controls the amount of slag discharged from the steel, and the thickness of the slag layer is less than 50mm. Step 2: Deoxidation slag washing According to the requirements of the final oxygen content and the acid-soluble aluminum content of the molten steel entering the station, during the steel-making process, a deoxidizer is first added to the molten steel for deoxidation, and then lime and slag washing agent are added for slag washing, and a large amount of argon blowing is used at the bottom of the molten steel for stirring, so that the generated Al2O3 inclusions are combined with the slag washing agent to form low-melting-point inclusions, which are quickly removed from the molten steel; wherein, the final oxygen content is controlled at ≤900ppm, the acid-soluble aluminum content requirement for entering the station is Als=0.035~0.050%, the deoxidizer is aluminum iron, and the specific process steps of deoxidation are as follows: in the early stage of steel-making, when the steel-making amount is 1 / 5, 200~400kg of aluminum iron is added at one time / furnace for deoxidation for 1~2min; the amount of lime added is 15 0~200kg / furnace, the slag washing agent is a special slag washing agent for CaO-Al2O3, and the addition amount is 50~70kg / furnace. The specific steps of slag washing are: lime is added to the molten steel from the high-level silo, and the slag washing agent is added to the molten steel manually at the same time. The slag washing agent must be added after the aluminum and iron are added, and the slag washing reaction takes 1~2min; the amount of aluminum and iron is adjusted according to the oxygen content. The specific adjustment method is that when the oxygen content is 700~900ppm, 300~350kg / furnace of aluminum and iron is used, and when the oxygen content is 500~700ppm, 200~300kg / furnace of aluminum and iron is used; large argon blowing stirring means that the flow rate of argon gas blown in can meet the diameter of the exposed area of ​​molten steel>500mm; Step 3: Alloying Continue to add silicon manganese and carburizer for alloying, control the converter tapping amount and control the acid-soluble aluminum content of molten steel at the argon blowing station; wherein, the specific process steps of alloying are as follows: after the molten steel is deoxidized and slag is washed, silicon manganese and carburizer are added successively when the tapping amount is 1 / 3, the amount of silicon manganese added is 450-500kg / furnace, the carburizer is 90 low-sulfur carburizer, the amount of which is 80-100kg / furnace, and the alloying reaction is 1-2min; the converter tapping amount is controlled at 70t / furnace, and the acid-soluble aluminum content of molten steel at the argon blowing station is controlled at Als=0.035-0.050%; Step 4: Argon blowing station After steel is tapped, the molten steel enters the argon blowing station. Depending on the tumbling of the molten steel, the argon pressure is adjusted to 0.2~0.5Mpa. The argon is blown for 2 minutes, with the molten steel surface tumbling but not violently blown. Then the argon blowing intensity is reduced and changed to medium argon blowing. At the same time, sampling and analysis are performed. According to the acid-soluble aluminum content of the molten steel, aluminum wire is used to adjust it to a qualified level. Titanium iron is then added to adjust the titanium content of the molten steel. After the molten steel composition is adjusted to a qualified level, small argon blowing is performed. Among them, when the acid-soluble aluminum content meets the requirements, aluminum wire is not fed. When the acid-soluble aluminum content meets the requirements, ferrotitanium is added to adjust the titanium content of the molten steel. If it is too low, feed aluminum wire to fine-tune the acid-soluble aluminum, and control the content to be 0.035%≤acid-soluble aluminum≤0.050%; the specific titanium iron is 70 titanium iron, and the addition amount is 80kg / furnace; large argon blowing refers to the argon flow rate that can meet the exposed area diameter of molten steel>500mm, medium argon blowing refers to the argon flow rate that can meet the exposed area diameter of molten steel of 300~500mm; small argon blowing refers to the argon flow rate that can meet the exposed area diameter of molten steel of 200~300mm; Step 5: Calcification treatment Carry out calcification treatment according to the acid-soluble aluminum content in the molten steel, feed the CaFe line, first blow argon for 2~3min, then feed the CaFe line for 200~300m, after completion, blow argon for ≥10min, add ladle composite insulation, exit the station and go on stage; the ladle composite insulation does not need to contain insulation with high silica, after the CaFe line is fed, it must be ensured that the soft blowing time is more than 10min before going on stage, the medium argon blowing and small argon blowing are consistent with step 4; Step 6: Protective pouring The molten steel is poured into the tundish, and then poured into the crystallizer with a long nozzle for protection. Open pouring is prohibited. When pouring, the long nozzle of the large ladle is first put on, and then the slide plate is opened for pouring. A high-alkalinity covering agent is added to the molten steel surface of the tundish to prevent the molten steel in the tundish from being exposed and to avoid secondary oxidation of the molten steel during pouring. The gap between the tundish cover plate and the tundish is completely sealed with refractory fiber and fire mud. The plug rod hole and other holes on the cover plate are processed into corresponding regular hole shapes with aluminum silicate fiber felt and then tightly covered. Step 7: Continuous Casting Control During the continuous casting process, the long shroud of the large ladle and the lower shroud of the middle ladle are protected by argon sealing during pouring to ensure that argon reaches the top of the long shroud. During the pouring process, the loss of acid-soluble aluminum is controlled within 0.010%, and the ratio of acid-soluble aluminum in the tundish steel to total aluminum is controlled to be ≥90%. The specific control method is to start pouring the ladle, first cover the long shroud, and then open the slide plate; then blow argon into the tundish, and seal the lower shroud of the tundish with argon. Under the full protection of pouring, the oxidation amount of acid-soluble aluminum in the molten steel is controlled to be less than 0.010%, thereby increasing the effective acid-soluble aluminum content; wherein, the casting billet pulling speed is 1.00-1.25m / min, the specific water content is 0.8-0.9L, and the high basicity covering agent refers to CaO / SiO2 with a mass ratio of >2.0, and the addition amount is 50-80kg / furnace.

[0023] The existing technology usually adopts the process route of converter smelting → argon station treatment → LF refining treatment → continuous casting to prepare aluminum-containing and titanium-containing slabs. In the preparation process, silicon manganese and carburizer are first added for alloying treatment, and then aluminum-iron deoxidizer is added for deoxidation treatment. In the LF refining process, lime and slag washing agent are added to remove Al2O3 and other inclusions by slag washing, and finally continuous casting is performed. This method has a long cycle and high cost. In the early smelting process, due to unstable production, large aluminum consumption in the production process, and staged aluminum addition, Al2O3 and other inclusions produced by deoxidation are not completely floated. During the casting process, the water inlet flocculation is serious, and the number of continuous casting furnaces is low, reaching only 15 to 20 furnaces at most. The present invention eliminates the segmented aluminum addition method by first deoxidizing slag washing and then alloying treatment, that is, adopting a large-medium-small argon blowing mode in the argon blowing station, adding aluminum wire in one step, omitting the LF refining treatment step while ensuring the dissolved aluminum content in molten steel, shortening the entire production cycle. It has been verified that the LF furnace refining production is eliminated, the production cycle is shortened by 40 minutes, and the production cost is reduced by 50 yuan / t. The process of the present invention completely solves the problem of continuous casting pouring nozzle floccules, and molten steel is continuously poured for 77 furnaces without floccules, and production is uninterrupted, which can be widely promoted and applied.

[0024] The above describes the specific embodiments of the present invention. The present invention is not limited to the above specific embodiments, and those skilled in the art may make various changes or modifications within the scope of the claims, which does not affect the essence of the present invention. In the absence of conflict, the embodiments of the present application and the features in the embodiments may be combined with each other at will.

Claims

1. A production process for increasing the number of continuous casting furnaces for aluminum- and titanium-containing slab molten steel, characterized in that: During the steelmaking and tapping process in the converter, first use a deoxidizer for deoxidation and a calcium slag washer for slag washing, and then under the action of argon stirring, the formed inclusions are quickly removed; then silicon manganese and a carburizer are added for alloying, the converter tapping amount is controlled, and the acid-soluble aluminum content of the molten steel entering the argon blowing station is controlled to meet the target requirements. The molten steel enters the argon blowing station, during which a large-medium-small argon blowing mode is adopted to even out the composition of the molten steel, adjust the titanium content with ferrotitanium, and remove deoxidation products; then after calcification treatment, a small argon blowing period of ≥10 minutes is performed; finally, protective pouring is performed during continuous casting.

2. The process for increasing the number of continuous casting furnaces of aluminum- and titanium-containing slab molten steel according to claim 1, characterized in that: The specific steps are as follows: Step 1: Converter steelmaking The converter is charged with molten iron, the requirements of which are: silicon = 0.10-0.80%, manganese ≤ 0.50%, phosphorus ≤ 0.250%, sulfur ≤ 0.015%, and the temperature is ≥ 1250°C for steelmaking. Then, the final composition of the converter is controlled to be: carbon = 0.05-0.15%, phosphorus ≤ 0.015%, and sulfur ≤ 0.015%; Step 2: Deoxidation slag washing According to the requirements of the final oxygen content and the acid-soluble aluminum content of the molten steel entering the station, during the steel-making process, a deoxidizer is first added to the molten steel for deoxidation, and then lime and slag washing agent are added for slag washing. A large amount of argon blowing is used at the bottom of the molten steel for stirring, so that the generated Al2O3 inclusions are combined with the slag washing agent to form low-melting-point inclusions, which are quickly removed from the molten steel; Step 3: Alloying Continue to add silicon manganese and carburizer for alloying, control the output of converter and the acid-soluble aluminum content of molten steel entering argon blowing station; Step 4: Argon blowing station After steel is tapped, the molten steel enters the argon blowing station. Depending on the tumbling of the molten steel, the argon pressure is adjusted to 0.2~0.5Mpa. The argon is blown for 2 minutes, with the molten steel surface tumbling but not violently blown. Then the argon blowing intensity is reduced to medium argon blowing. At the same time, sampling is performed for analysis. According to the acid-soluble aluminum content of the molten steel, aluminum wire is used to adjust it to a qualified level. Titanium iron is then added to adjust the titanium content of the molten steel. After the molten steel composition is adjusted to a qualified level, the argon blowing is changed to small level. Step 5: Calcification treatment Calcification treatment is carried out according to the acid-soluble aluminum content in the molten steel. First, argon is blown for 2~3 minutes, and then 200~300m of CaFe line is fed. After completion, argon is blown for ≥10 minutes, and the steel ladle composite insulation agent is added to the station and put on the platform; Step 6: Protective pouring The molten steel is poured into the tundish, and then poured into the crystallizer with a long nozzle for protection. Open pouring is prohibited. When pouring, the long nozzle of the large ladle is first put on, and then the slide plate is opened for pouring. A high-alkalinity covering agent is added to the molten steel surface of the tundish to prevent the molten steel in the tundish from being exposed and to avoid secondary oxidation of the molten steel during pouring. The gap between the tundish cover plate and the tundish is completely sealed with refractory fiber and fire mud. The plug rod hole and other holes on the cover plate are processed into corresponding regular hole shapes with aluminum silicate fiber felt and then tightly covered. Step 7: Continuous Casting Control During the continuous casting process, the long shroud of the large ladle and the lower shroud of the middle ladle are cast with argon sealing protection to ensure that the argon gas reaches the top of the long shroud. During the casting process, the loss of acid-soluble aluminum is controlled within 0.010%, and the ratio of acid-soluble aluminum to total aluminum in the tundish steel is controlled to be ≥90%.

3. The process for increasing the number of continuous casting furnaces of aluminum- and titanium-containing slab molten steel according to claim 1, characterized in that: In the step 1, the converter uses a slide plate to block the slag, and the amount of slag discharged during steel tapping is strictly controlled, and the thickness of the slag layer is less than 50 mm.

4. The process for increasing the number of continuous casting furnaces of aluminum- and titanium-containing slab molten steel according to claim 1, characterized in that: In the step 2, the end point oxygen content is controlled at ≤900ppm, and the acid-soluble aluminum content at the station is required to be Als=0.035-0.050%; The deoxidizer is aluminum iron, and the specific process step of the deoxidation is to add 200-400 kg of aluminum iron / furnace at one time in the early stage of steel tapping when the steel tapping amount is 1 / 5; The amount of lime added is 150-200 kg / furnace, the slag washing agent is a special slag washing agent for CaO-Al2O3, and the amount of slag washing agent added is 50-70 kg / furnace. The specific steps of slag washing are: lime is added into molten steel from a high-level silo, and the slag washing agent is added into the molten steel manually at the same time, and the slag washing agent must be added after the aluminum and iron are added; The large argon blowing stirring means that the flow rate of argon gas blown in can meet the requirement that the diameter of the exposed area of ​​molten steel is greater than 500mm; Among them, the amount of aluminum iron added is adjusted according to the oxygen content. The specific adjustment method is that when the oxygen content is 700~900ppm, 300~350kg / furnace of aluminum iron is used; when the oxygen content is 500~700ppm, 200~300kg / furnace of aluminum iron is used.

5. The process for increasing the number of continuous casting furnaces for aluminum- and titanium-containing slab molten steel according to claim 1, characterized in that: In the step three, the specific process steps of alloying are as follows: after the molten steel is deoxidized and the slag is washed, silicon manganese and a recarburizer are added successively when the tapping amount is 1 / 3, the amount of silicon manganese added is 450-500 kg / furnace, the recarburizer is a 90 low-sulfur recarburizer, and the amount of 90 low-sulfur recarburizer added is 80-100 kg / furnace; the converter tapping amount is controlled at 70 t / furnace, and the acid-soluble aluminum content of the molten steel at the argon blowing station is controlled at Als=0.035-0.050%.

6. The process for increasing the number of continuous casting furnaces of aluminum- and titanium-containing slab molten steel according to claim 1, characterized in that: In the step 4, when the acid-soluble aluminum content meets the requirements, no aluminum wire is fed; when the acid-soluble aluminum content is low, aluminum wire is fed to fine-tune the acid-soluble aluminum to control the content to be 0.035%≤acid-soluble aluminum≤0.050%; the titanium iron is specifically 70 titanium iron, and the addition amount is 80kg / furnace.

7. The process for increasing the number of continuous casting furnaces of aluminum- and titanium-containing slab molten steel according to claim 1, characterized in that: In step 4 and step 5, the large argon blowing means that the argon flow rate blown in can meet the requirement that the diameter of the exposed area of ​​molten steel is greater than 500mm, the medium argon blowing means that the argon flow rate blown in can meet the requirement that the diameter of the exposed area of ​​molten steel is 300-500mm; the small argon blowing means that the argon flow rate blown in can meet the requirement that the diameter of the exposed area of ​​molten steel is 200-300mm.

8. The process for increasing the number of continuous casting furnaces of aluminum- and titanium-containing slab molten steel according to claim 1, characterized in that: In the step 5, the ladle composite insulation does not need to contain high silicon dioxide insulation. After the CaFe wire is fed, the soft blowing time must be guaranteed to be more than 10 minutes before going on stage.

9. The process for increasing the number of continuous casting furnaces of aluminum- and titanium-containing slab molten steel according to claim 1, characterized in that: In the step seven, the casting speed is 1.00-1.25 m / min, the specific water content is 0.8-0.9 L, and the high basicity covering agent refers to CaO / SiO2 with a mass ratio of >2.0, and the added amount is 50-80 kg / furnace.

10. The process for increasing the number of continuous casting furnaces for aluminum- and titanium-containing slab molten steel according to claim 1, characterized in that: In the step seven, the loss of acid-soluble aluminum is controlled within 0.010% during the pouring process, and the ratio of acid-soluble aluminum in the tundish steel to total aluminum is controlled to be ≥90%. The control method is as follows: start pouring the ladle, first install a long water nozzle, and then open the slide plate; then blow argon gas into the tundish, and seal the lower water nozzle of the tundish with argon. Under the full protection of pouring, the oxidation amount of acid-soluble aluminum in the molten steel is controlled to be less than 0.010%, thereby increasing the effective acid-soluble aluminum content.

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