A method for improving the success rate of pouring low-carbon aluminum steel

Abstract

The present invention discloses a method for improving the success rate of low-carbon aluminum steel casting, belonging to the technical field of steelmaking production process, comprising the following steps: modifying the tundish and configuring a roaster, then performing a roasting operation on the tundish and maintaining the roasting until before casting; adding a 5-minute low-air-volume roasting operation before casting to the tundish to maintain the molten steel in a reducing atmosphere during the casting process and prevent oxidation of the molten steel during casting. The present invention adopts a two-stage roasting process to form a reducing atmosphere in the tundish, prevent secondary oxidation of the molten steel during casting, reduce the blockage of the tundish water inlet by aluminum oxide inclusions, improve the stability of molten steel casting, and improve the success rate of molten steel casting; at the same time, a 5-minute low-air-volume roasting data acquisition curve before casting is added to the display of the roaster operation box to improve the accuracy of the roasting operation and further ensure the success rate of molten steel casting.

Description

Technical Field

[0001] The present invention relates to the technical field of steelmaking production technology, in particular to a method for improving the success rate of low-carbon aluminum steel casting. Background Art

[0002] Continuous casting, an essential process in modern steel metallurgical production, plays a crucial role in maintaining the continuity of the entire production process and improving the production efficiency and product quality of steel companies. The start of pouring is a crucial step in continuous casting production. Its purpose is to divert molten steel from the ladle into the crystallizer, and then cast the molten steel into billets through the tundish to facilitate the subsequent rolling process. A high success rate in the start of pouring is crucial for achieving stable and efficient production.

[0003] The cross-sectional dimensions of the billet continuous casting machine are 140*140mm, and the upper water inlet of the tundish is only 22mm. The aluminum content of the aluminum-added steel (ML08AL) is 0.025%~0.055%. During the later continuous casting process, the molten steel will undergo secondary oxidation when it comes into contact with air. The aluminum oxide inclusions produced by oxidation will gather around the upper water inlet of the tundish. After multiple continuous castings, a large amount of aluminum oxide inclusions will accumulate at the water inlet of the tundish, blocking the upper water inlet of the tundish. As a result, the molten steel cannot be cast normally in the tundish, resulting in unsuccessful casting. The conventional operation to address this problem is to provide protective casting and use argon gas to replace the air in the tundish before pouring to reduce the secondary oxidation of the molten steel. However, the replacement effect is not good, and the molten steel is still easily oxidized during the pouring process, resulting in unsuccessful casting. Summary of the Invention

[0004] Technical problem to be solved: In view of the problem of unsuccessful pouring caused by blockage of the tundish in the continuous casting technology in the prior art, the present invention provides a method for improving the success rate of pouring of low-carbon aluminum steel. A two-stage baking process is adopted to form a reducing atmosphere in the tundish to prevent the secondary oxidation of the molten steel during pouring, reduce the blockage of the upper water inlet of the tundish by aluminum oxide inclusions, and improve the success rate of pouring of molten steel.

[0005] Technical solution: The method of improving the success rate of low-carbon aluminum steel casting according to the present invention comprises the following steps:

[0006] Step 1: Modify the tundish and configure a baker, then bake the tundish and keep baking until pouring begins;

[0007] Step 2: Before pouring, add 5 minutes of small air volume baking to the tundish to maintain the molten steel in a reducing atmosphere during the pouring process to prevent oxidation of the molten steel during the casting process.

[0008] Preferably, the tundish in step 1 comprises a tundish shell and a refractory lining layer arranged on the inner wall of the tundish shell;

[0009] The roaster includes a roaster cover plate correspondingly buckled on the tundish, and a plurality of roasting slots are correspondingly opened on the roaster cover plate; a roasting main pipe is provided on one side above the roaster cover plate, and the roasting main pipe is provided with a plurality of roasting branch pipes corresponding to the roasting slots;

[0010] The roaster is equipped with a roaster operating box, which controls and adjusts the parameters of the roasting gas flow and the compressed air flow.

[0011] Preferably, the specific steps of the tundish baking operation in step 1 are: lowering the baking device cover and snapping it onto the tundish shell, igniting the flame of gas and compressed air through the baking main pipe and the baking branch pipe to spray into the tundish to heat the refractory lining, maintaining the temperature of the refractory lining at 900°C, and reducing the temperature drop of the molten steel when pouring.

[0012] Preferably, in step 1, the tundish is baked by controlling the baking box to bake at low, medium, or high heat;

[0013] Among them, the gas flow rate of low-fire baking is 100~150 L / min, the air volume is 300 L / min, and the baking time is 1 hour;

[0014] The gas flow rate for medium-fire baking is 200-300 L / min, the air volume is 300 L / min, and the baking time is 1 hour;

[0015] The gas flow rate for high-fire baking is 300~400 L / min, the air volume is 500 L / min, and the baking time is 1~2h.

[0016] Preferably, the specific steps for setting the gas and compressed air for low, medium and high fire in step 1 are: select the button gas setting → enter the gas setting flow → confirm, if the input is incorrect, select cancel and reset according to the steps; select the button air volume setting → enter the air volume setting flow → confirm, if the input is incorrect, select cancel and reset according to the steps.

[0017] Preferably, in step 1, the baking condition of the refractory lining of the tundish should be observed more frequently during the high-fire baking process. If the refractory lining of the tundish is found to be obviously shiny and white, and the temperature of the tundish shell exceeds 800°C, it indicates that the refractory lining is over-baked. The process parameters are adjusted through the baking machine operating box to reduce the compressed air volume to 300 L / min, reduce the gas flow to 100 L / min, and reduce the tundish shell temperature to 600~700°C to reduce the baking oxidation phenomenon of the refractory lining of the tundish.

[0018] Preferably, in step 2, the specific steps of adding 5 minutes of small air volume baking before pouring are as follows: adjust the gas flow rate to 1000L / min and the compressed air volume to 200L / min, continue baking for 5 minutes, extract the baking heat flow to the upper water inlet of the tundish to heat and bake the upper water inlet until it is closed when ready to pour.

[0019] Preferably, the baking machine operating box in step 2 includes a gas concentration detection mechanism and a display, and the display adds a small air volume baking data acquisition curve display 5 minutes before pouring. After the query set parameters are displayed on the display, by observing the small air volume curve, it is confirmed whether the set gas concentration is reached to ensure normal pouring.

[0020] Compared with the prior art, the present invention has at least the following beneficial effects:

[0021] 1. The method of the present invention adopts a two-stage baking process to form a reducing atmosphere in the tundish, preventing secondary oxidation of molten steel during pouring, reducing the blockage of the tundish water inlet by aluminum oxide inclusions, improving the stability of molten steel casting, and increasing the success rate of molten steel pouring. The success rate of ML08AL steel pouring has increased from 75% to 98%, reducing one unsuccessful tundish pouring attempt per month, thereby reducing production costs.

[0022] 2. Add 5 minutes of low-air-volume baking time to the tundish before pouring to further improve the reducing atmosphere of the refractory lining of the tundish and enhance the protective pouring effect of the tundish; at the same time, add a 5-minute low-air-volume baking data acquisition curve before pouring to the display of the baking machine operation box to improve the accuracy of the baking operation and further ensure the success rate of molten steel pouring. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a flow chart of a method for improving the success rate of pouring low-carbon aluminum steel according to the present invention;

[0024] Figure 2 This is a schematic diagram of the installation structure of the tundish and the roaster of the present invention;

[0025] Figure 3 This is a curve chart showing the baking data collection of small air volume 5 minutes before pouring, as displayed on the baking device display of the present invention.

[0026] Reference numerals: 1, tundish; 2, roaster; 21, roasting main pipe; 22, roasting branch pipe; 23, roaster cover; 24, roasting notch; 3, roaster operating box. DETAILED DESCRIPTION

[0027] To make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the following Figures 1-3The technical solutions of the embodiments of the present invention are clearly and completely described. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the described embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field are within the scope of protection of the present invention.

[0028] like Figures 1-3 As shown, the present invention discloses a method for improving the success rate of low-carbon aluminum steel casting, comprising the following steps:

[0029] Step 1: Modify the tundish 1 and install a roaster 2. The tundish 1 comprises a tundish shell and a refractory lining on its inner wall. The refractory lining is primarily composed of magnesium oxide, which has a melting point of approximately 3000°C. Normal molten steel temperatures are around 1600°C, indicating that the refractory lining has sufficient high-temperature resistance. The roaster 2 includes a roaster cover 23 that snaps onto the tundish 1. The roaster cover 23 is provided with multiple roasting notches 24 corresponding to the notches. A roasting main pipe 21 is located above the roaster cover 23, with multiple roasting branches 22 corresponding to the notches 24. The roaster 2 also includes an air supply system and an ignition device connected to the roasting main pipe 21. These systems provide gas and compressed air to the roaster 2, generating high-temperature airflow to heat the refractory lining of the tundish 1. The roaster 2 is also equipped with a roaster control box 3, which controls and adjusts the roasting gas and compressed air flow parameters.

[0030] The specific steps of the tundish baking operation are as follows: lower the baking device cover 23 and snap it onto the tundish shell; ignite the flame of coal gas and compressed air through the baking main pipe 21 and the baking branch pipe 22 and spray it into the tundish to heat the refractory lining, maintain the temperature of the refractory lining at 900°C, and reduce the temperature drop of the molten steel when it is poured.

[0031] The tundish baking operation is controlled by the baking machine operating box 3, with the baking operation of low, medium, and high heat. Tundish 1 is baked and maintained until pouring begins. For low-heat baking, the gas flow rate is 100-150 L / min, the air volume is 300 L / min, and the baking time is 1 hour; for medium-heat baking, the gas flow rate is 200-300 L / min, the air volume is 300 L / min, and the baking time is 1 hour; for high-heat baking, the gas flow rate is 300-400 L / min, the air volume is 500 L / min, and the baking time is 1-2 hours. It should be noted that the gas flow rate for low-fire baking can be selected as 100, 125, and 150 L / min, the gas flow rate for medium-fire baking is 200, 250, and 300 L / min, and the gas flow rate for high-fire baking is 300, 350, and 400 L / min. The specific value of the gas flow rate is dynamically adjusted according to demand to meet the ladle baking operation and ensure that the refractory lining is not over-baked.

[0032] The specific steps for setting the gas and compressed air for low, medium and high fire are as follows: Select the button for gas setting → enter the set gas flow → Confirm. If the input is incorrect, select Cancel and reset according to the steps; Select the button for air volume setting → enter the set air volume flow → Confirm. If the input is incorrect, select Cancel and reset according to the steps.

[0033] During the high-fire baking process, the baking condition of the refractory lining of the tundish should be observed frequently. If the refractory lining of the tundish is found to be noticeably shiny and white, it is a sign of over-baking and oxidation of the refractory lining. This can be confirmed by measuring the temperature of the tundish shell. If the tundish shell temperature exceeds 800°C, it indicates that the refractory lining is over-baked. Therefore, the process parameters should be adjusted through the baking machine operating box, reducing the compressed air volume to 300 L / min and the gas flow rate to 100 L / min. This will lower the tundish shell temperature to 600-700°C and reduce the baking oxidation of the refractory lining of the tundish. During the baking process, the color of the refractory lining of the tundish can be observed frequently based on experience. If the color of the refractory lining is dark red, it can be preliminarily determined that the refractory lining of the tundish meets the baking requirements.

[0034] This step uses a baking process to form a reducing atmosphere in the tundish, preventing secondary oxidation of the molten steel during pouring, reducing the blockage of the tundish's water inlet by aluminum oxide inclusions, improving the stability of molten steel casting, and increasing the success rate of molten steel pouring.

[0035] Step 2: Before pouring, add 5 minutes of small air volume baking to the tundish to maintain the molten steel in a reducing atmosphere during the pouring process to prevent oxidation of the molten steel during the casting process. The specific steps of adding 5 minutes of small air volume baking before pouring are: adjust the gas flow rate to 1000L / min and the compressed air volume to 200L / min, continue baking for 5 minutes, extract the baking heat flow to the upper water inlet of the tundish to heat and bake the upper water inlet until it is closed when ready to pour. The baking machine operation box 3 includes a gas concentration detection mechanism and a display. The display adds a 5-minute small air volume baking data acquisition curve display before pouring (such as Figure 3 After querying the set parameters on the display, observe the small air volume curve to confirm whether the set gas concentration is reached to ensure normal pouring.

[0036] This step adds 5 minutes of low-air-volume baking time to the tundish before pouring, further enhancing the reducing atmosphere of the refractory lining and strengthening the tundish's protective pouring effect. A 5-minute low-air-volume baking data acquisition curve is also added to the display of the baking unit's operating box, improving the accuracy of baking operations and further ensuring the success rate of molten steel pouring. The success rate of ML08AL steel pouring has increased from 75% to 98%. This reduces one unsuccessful tundish pour per month, and at a cost of 27,200 yuan per tundish, this saves 27,200 yuan in tundish costs per month. Furthermore, assuming the tundish cold steel capacity is 40 tons, each ton of cold steel is considered defective at 400 yuan. This translates to an annual profit of 27,200 yuan * 12 months + 400 yuan / 10,000 yuan * 40 tons * 12 months = 518,400 yuan, thus reducing production costs.

[0037] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for improving the success rate of pouring low-carbon aluminum steel, characterized in that: The following steps are involved: Step 1: transform the tundish (1) and configure a roaster (2), then perform a roasting operation on the tundish (1) and maintain the roasting until the start of pouring; wherein, the tundish (1) includes a tundish shell and a refractory lining layer arranged on the inner wall of the tundish shell; the roaster (2) includes a roaster cover (23) correspondingly fastened to the tundish (1), and the roaster cover (23) is correspondingly provided with a plurality of roasting slots (24); a roasting main pipe (21) is provided on one side above the roaster cover (23), and the roasting main pipe (21) is provided with a plurality of roasting branch pipes (22) corresponding to the roasting slots (24); the roaster (2) is provided with a roaster operation box (3), and the roaster operation box (3) controls and adjusts the roasting gas flow rate and the compressed air flow rate parameters; and the roasting of the tundish is controlled by the roaster operation box (3) to perform the roasting operation according to low fire, medium fire and high fire; wherein, the gas flow rate of low fire roasting is 100~150 L / min, and the air volume is 300 L / min, baking time is 1h; medium-fire baking gas flow rate is 200~300 L / min, air volume is 300 L / min, baking time is 1h; high-fire baking gas flow rate is 300~400 L / min, air volume is 500 L / min, baking time is 1~2h; Step 2: Before pouring, add 5 minutes of small air volume baking to the tundish to maintain the molten steel in a reducing atmosphere during the pouring process to prevent the molten steel from oxidizing during the casting process; the specific steps of adding 5 minutes of small air volume baking before pouring are as follows: adjust the gas flow rate to 1000L / min and the compressed air volume to 200L / min, and continue baking for 5 minutes. The baking heat flow is extracted to the upper water inlet of the tundish to heat and bake the upper water inlet until it is closed when ready to pour.

2. The method for improving the success rate of pouring low carbon aluminum steel according to claim 1, characterized in that: The specific steps of the tundish baking operation in step 1 are as follows: lower the baking device cover (23) and snap it onto the tundish shell, ignite the flame of gas and compressed air through the baking main pipe (21) and the baking branch pipe (22) and spray it into the tundish to heat the refractory lining, maintain the temperature of the refractory lining at 900°C, and reduce the temperature drop of the molten steel when pouring.

3. The method for improving the success rate of pouring low carbon aluminum steel according to claim 2, characterized in that: Specific steps for setting the gas and compressed air for low, medium and high fire in step 1: Select the button Gas Setting → Enter the set gas flow → Confirm. If the input is incorrect, select Cancel and reset according to the steps; Select the button Air Volume Setting → Enter the set air volume flow → Confirm. If the input is incorrect, select Cancel and reset according to the steps.

4. The method for improving the success rate of pouring low carbon aluminum steel according to claim 3, characterized in that: During the high-fire baking process in step 1, the baking condition of the refractory lining of the tundish should be observed more frequently. If the refractory lining of the tundish is found to be obviously shiny and white, and the temperature of the tundish shell exceeds 800°C, it indicates that the refractory lining is over-baked. Adjust the process parameters through the baking machine operating box, reduce the compressed air volume to 300 L / min, reduce the gas flow to 100 L / min, and reduce the tundish shell temperature to 600~700°C to reduce the baking oxidation phenomenon of the refractory lining of the tundish.

5. The method for improving the success rate of pouring low carbon aluminum steel according to claim 1, characterized in that: In step 2, the baking machine operating box (3) includes a gas concentration detection mechanism and a display. The display increases the display of a small air volume baking data acquisition curve 5 minutes before pouring. After the query setting parameters are displayed on the display, by observing the small air volume curve, it is confirmed whether the set gas concentration is reached to ensure normal pouring.

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