Calculation method for removal amount of TiO2 inclusions in ladle casting area in titanium-containing steel continuous casting process and application

Abstract

The invention provides a method for calculating the removal amount of TiO2 inclusions in a tundish casting area in the titanium-containing steel continuous casting process. The method comprises the steps that S1, the CaO content of a tundish covering agent before use is detected; (S2) the titanium-containing molten steel is subjected to continuous casting, a tundish is cast into a first furnace, and a certain amount of tundish covering agent is added into a tundish casting area; the content of CaO and the content of TiO2 in tundish slag are detected respectively in the last furnace of tundish casting; s3) calculating the weight of CaO in the tundish covering agent; calculating the content ratio of TiO2 to CaO in the tundish slag; and S4) according to the mass conservation of CaO, the weight of TiO2 in the tundish slag is the removal amount of TiO2 inclusions in the tundish casting area. The calculation method provided by the invention can provide data support for optimal design of a tundish covering agent matched with the titanium-containing steel and other tundish refractory materials, so that the cleanliness of the titanium-containing steel is improved, and inclusions are reduced.

Description

Technical Field

[0001] The invention relates to the field of metallurgical technology, and in particular to a method for calculating the amount of TiO2 inclusion removal in a ladle casting zone during a titanium-containing steel continuous casting process and its application. Background Art

[0002] As an important alloying element, titanium can effectively improve the mechanical properties of steel and has been widely used in the steel industry. With the addition of titanium in steel, titanium-containing steel will be affected by secondary oxidation and other factors during smelting and continuous casting, which will produce more TiO2 inclusions and affect the cleanliness of molten steel. If the TiO2 inclusions in titanium-containing steel are not fully removed by floating, more TiO2 inclusions in the steel will affect the mechanical properties and surface quality of the product.

[0003] Focusing on the production process technology of titanium-containing steel, researchers have designed and proposed many technical solutions in combination with the characteristics of steel grades. For example: Chinese patent with publication number CN118207485A discloses a hot-rolled strip steel for automobile hollow stabilizer bars and its production method. Light pressure is implemented in the continuous casting sector, electromagnetic stirring is turned on in the continuous casting second cooling zone, and the temperature of the tundish is controlled to be superheated at 10 to 25°C. The obtained hot-rolled strip steel solves the problems of cracking and easy surface decarburization of automobile stabilizer bar steel during processing. The hollow stabilizer bar steel has the advantage of small core segregation. Chinese patent with publication number CN118291845A discloses a method for controlling the titanium content in an electrical steel billet, achieving the goal of a stable titanium content of less than 0.0015wt% in a high-aluminum electrical steel billet, thereby ensuring the high quality and stability of the electrical steel prepared by the electrical steel billet. The Chinese patent with publication number CN118287644A discloses a continuous casting protective slag suitable for high-titanium, low-aluminum, high-oxygen welding wire steel, which can improve the ability of protective slag to control heat transfer and ensure the stability of protective slag performance after slag reaction and absorption of inclusions. The Chinese patent with publication number CN118127408A discloses a preparation method of 3.0-12.0mm titanium microalloyed H40 steel strip for petroleum casing: molten iron pretreatment, converter composite blowing, LF refining, continuous casting, slab heating, hot rolling, laminar cooling and coiling; the hot rolling includes heating furnace, rough rolling and finishing rolling; it produces H40 hot-rolled steel strip that meets the requirements for petroleum casing by optimizing the composition design and rolling process, and the product cost is low. A Chinese patent with publication number CN117845123A discloses a method for manufacturing 1000MPa grade high titanium steel. By stably controlling multiple node components in the production process, the fluctuation of titanium content in the high titanium steel is reduced, and the stability of product production is improved.

[0004] Continuous casting is a key process in the production process of titanium-containing steel and is closely related to product quality. In particular, the tundish, as an important metallurgical container in the continuous casting process, plays an important role in the floating removal of TiO2 inclusions in titanium-containing steel. Quantitatively and accurately evaluating the floating removal amount of TiO2 inclusions in the tundish during the continuous casting process of titanium-containing steel is the key basis for optimizing the design of supporting tundish covering agents and other tundish refractory materials. However, the above patent mainly proposes a process technology solution for the full process design of titanium-containing steel, and does not involve the evaluation and calculation method of the floating removal amount of TiO2 inclusions in the tundish during the continuous casting process. Summary of the invention

[0005] The technical problem solved by the present invention is to provide a method for calculating the amount of TiO2 inclusions removed in the ladle casting area during the continuous casting process of titanium-containing steel. The calculation method provided by the present application can accurately calculate and evaluate the amount of TiO2 inclusions removed in the ladle casting area during the casting process.

[0006] In view of this, the present application provides a method for calculating the amount of TiO2 inclusion removal in the ladle casting zone during the continuous casting process of titanium-containing steel, comprising the following steps:

[0007] S1) Detect the CaO content of the middle package covering agent before use, denoted as w 1C , wt%;

[0008] S2) continuously casting the titanium-containing molten steel, pouring the first furnace of the tundish, adding the tundish covering agent into the tundish casting area, and the added weight of the tundish covering agent is recorded as W1, kg;

[0009] In the last batch of tundish casting, the contents of CaO and TiO2 in the tundish slag were detected and recorded as w 2C 、w 2T , wt%;

[0010] S3) Calculate the weight of CaO in the middle package covering agent, recorded as W 1CaO , W 1CaO =W1×w 1C , kg;

[0011] Calculate the content ratio of TiO2 and CaO in the tundish slag, denoted as R, R = w 2T / w 2C ;

[0012] S4) According to the CaO mass conservation law, the weight of TiO2 in the tundish slag is recorded as W 2TiO2 , W 2TiO2 =W 1CaO ×R,kg.

[0013] Preferably, the middle package covering agent does not contain TiO2.

[0014] Preferably, in step S1), the detected amount of the middle package covering agent is ≥100g.

[0015] Preferably, in step S1), the detected amount of the middle package covering agent is 200-300 g.

[0016] Preferably, in step S2), the timing of adding the tundish covering agent is: the weight of the molten steel in the tundish reaches 40-60wt% of the nominal capacity.

[0017] Preferably, in step S2), the timing for detecting the tundish slag is when the weight of the molten steel in the ladle remains 30-50wt%.

[0018] Preferably, in step S2), the detected amount of the middle ladle slag is ≥100g.

[0019] Preferably, in step S2), the detected amount of the middle bag slag is 200-300g.

[0020] The present application also provides the application of the calculation method in the design of the middle package covering agent.

[0021] The present application provides a method for calculating the amount of TiO2 inclusions removed in a ladle casting area during continuous casting of titanium-containing steel. The method first detects the CaO content of a tundish covering agent before use. During continuous casting of titanium-containing molten steel, the tundish is opened for the first furnace, and the tundish covering agent is added to the tundish casting area, and the amount of the tundish covering agent added is marked. After the last furnace of tundish casting, the contents of CaO and TiO2 in the tundish slag are detected, and the content of CaO in the tundish covering agent and the content ratio of TiO2 to CaO in the tundish slag are calculated respectively. Finally, the TiO2 in the tundish slag is obtained according to the CaO mass conservation law. Since the main materials of the refractory materials in the tundish casting area are MgO-C and Al2O3-C, which do not contain TiO2, the TiO2 in the tundish slag can be considered to come from the titanium-containing molten steel. 2TiO2 That is, the weight of TiO2 inclusions in molten steel that floats up into the tundish slag. Therefore, the calculation method provided in this application is based on the calculation method for the floating removal amount of TiO2 inclusions in the tundish casting area during the continuous casting of titanium-containing steel with its own components in the tundish slag, which can accurately calculate and evaluate the floating removal amount of TiO2 inclusions in the tundish casting area of ​​titanium-containing steel during the casting process, thereby providing data support for optimizing the design of supporting tundish covering agents and improving their ability to adsorb and remove TiO2 inclusions in molten steel. This invention can be promoted and applied in the industry. DETAILED DESCRIPTION

[0022] In order to further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, rather than limiting the claims of the present invention.

[0023] In view of the lack of a quantitative calculation method for the removal of TiO2 inclusions in the intermediate ladle casting area of ​​the continuous casting process in the prior art, the present invention proposes a calculation method for the removal of TiO2 inclusions in the intermediate ladle casting area of ​​the continuous casting process of titanium-containing steel based on the inherent composition of the intermediate ladle slag. Under the premise of not affecting the smooth progress of the intermediate ladle casting process and the performance of the auxiliary material components, the intermediate ladle slag composition changes are used to accurately calculate and evaluate the adsorption and removal effect of the intermediate ladle slag on the TiO2 inclusions in the molten steel, providing accurate data support for optimizing and adjusting the intermediate ladle covering agent and other process parameters. The embodiment of the present invention discloses a calculation method for the removal of TiO2 inclusions in the intermediate ladle casting area of ​​the continuous casting process of titanium-containing steel, comprising the following steps:

[0024] S1) Detect the CaO content of the middle package covering agent before use, denoted as w 1C , wt%;

[0025] S2) continuously casting the titanium-containing molten steel, pouring the first furnace of the tundish, adding the tundish covering agent into the tundish casting area, and the added weight of the tundish covering agent is recorded as W1, kg;

[0026] In the last batch of tundish casting, the contents of CaO and TiO2 in the tundish slag were detected and recorded as w 2C 、w 2T , wt%;

[0027] S3) Calculate the weight of CaO in the middle package covering agent, recorded as W 1CaO , W 1CaO =W1×w 1C , kg;

[0028] Calculate the content ratio of TiO2 and CaO in the tundish slag, denoted as R, R = w 2T / w 2C ;

[0029] S4) According to the CaO mass conservation law, the weight of TiO2 in the tundish slag is recorded as W 2TiO2 , W 2TiO2 =W 1CaO ×R,kg.

[0030] In the calculation method of the amount of TiO2 inclusions removed in the ladle casting area during the continuous casting of titanium-containing steel, the present application first detects the content of CaO in the middle ladle covering agent. In this process, the middle ladle covering agent preferably uses a middle ladle covering agent sample of ≥100g. Specifically, the detection amount of the middle ladle covering agent is 200-300g. In addition, the other components in the middle ladle covering agent are components well known to those skilled in the art, and the present application does not impose any special restrictions on this. Specifically, the main components of the middle ladle covering agent include: CaO 30-50wt%, Al2O3 20-35wt%, MgO 5-10wt%, SiO2<7wt%, and does not include TiO2. CaO is one of the main components in the covering agent, and its content is relatively high, and it is easy to accurately detect and determine; importantly, in the middle ladle casting process, since the refractory material in the middle ladle casting area does not contain CaO, the CaO in the covering agent can be considered to be conserved in mass. Therefore, in the present application, CaO is used as a marker, and the weight of other components can be finally determined by detecting the content of other components and the CaO content in the covering agent during the tundish casting process, and then according to the ratio of the content of other components to the CaO content.

[0031] In the process of pouring steel, the first furnace is poured in the tundish. Preferably, when the weight of the molten steel in the tundish reaches 40-60wt% of the nominal capacity, the above-mentioned tundish covering agent is added to the tundish casting area and other areas. The weight of the tundish covering agent added to the casting area is recorded as W1, kg. When the tundish is cast to the last furnace, the CaO and TiO2 contents in the tundish slag (formed by the melting of the tundish covering agent and the absorption of inclusions) in the tundish casting area are detected and recorded as w 2C 、w 2T , wt%; During the casting process, when the remaining molten steel in the large ladle is too little, the temperature of the molten steel in the tundish is low, which may affect the slag-forming performance of the slag in the tundish impact zone, and the slag in the tundish may form a crust, which makes it more difficult to take slag samples from the tundish slag, and the composition of the slag samples taken out is large. When the remaining steel in the large ladle is too high, the shroud is still eroded during the casting of the remaining molten steel in the large ladle, resulting in a small calculated erosion weight of the shroud. In view of this, the detection time of CaO and TiO2 in the tundish slag is selected when the weight of the large ladle molten steel is 30-50%.

[0032] Based on the content and weight detected above, the weight of CaO in the coating agent is calculated and recorded as W 1CaO , W 1CaO =W1×w 1C ; Calculate the content ratio of TiO2 and CaO in the tundish slag, R = w 2T / w 2C .

[0033] Since a retaining wall is usually installed between the tundish casting area and the impact area, it can effectively block the slag (containing CaO) from the ladle from flowing to the casting area. At the same time, the refractory in the casting area does not contain CaO. Therefore, it can be considered that the mass of CaO in the tundish covering agent added to the casting area is conserved. Based on this, the weight of TiO2 in the tundish slag in the casting area when the tundish is cast for the last batch can be quantitatively calculated. 2TiO2 =W 1CaO ×R. Furthermore, since the main materials of the refractory materials in the casting area of ​​the tundish are MgO-C and Al2O3-C, which do not contain TiO2, it can be considered that the weight of TiO2 in the tundish slag is W 2TiO2 All from titanium-containing molten steel, W 2TiO2 It is the weight of TiO2 inclusions in molten steel that floats up into the tundish slag.

[0034] The calculation method provided in the present application is applicable to the calculation of the amount of TiO2 inclusions removed in the continuous casting zone during the continuous casting of titanium-containing steel, wherein the titanium-containing steel is a type of titanium-containing steel well known to those skilled in the art; illustratively, the titanium-containing steel is titanium-containing ultra-low carbon steel.

[0035] The present application also provides the application of the above calculation method in the design of the middle package covering agent.

[0036] The calculation method provided by the present invention can provide data support for optimizing the design of the middle package covering agent and other refractory materials for titanium-containing steel, thereby improving the cleanliness of titanium-containing steel and reducing the economic losses caused by inclusions and other problems. It is expected to create an annual benefit of at least 500,000 yuan.

[0037] In order to further understand the present invention, a method for calculating the amount of TiO2 inclusions removed in the ladle casting zone during the continuous casting of titanium-containing steel provided by the present invention is described in detail below in conjunction with embodiments. The protection scope of the present invention is not limited by the following embodiments.

[0038] Example Calculation of the weight of TiO2 inclusions removed by floating in the post-casting zone of the molten steel in a two-stream 70-ton tundish continuous casting of 10 furnaces of titanium-containing ultra-low carbon steel

[0039] (1) Take 200g of the middle package covering agent (without TiO2) before use and detect and analyze its CaO content w 1C =30.75%;

[0040] (2) When the titanium-containing steel is continuously cast, the first heat is poured from the tundish. When the weight of the molten steel in the tundish reaches 60% of the nominal capacity, a certain amount of covering agent is added to the casting area and other areas of the tundish. The weight of the covering agent added to the casting area is W1 = 160 kg.

[0041] (3) In the last batch of tundish casting, when the weight of the molten steel in the large ladle remains at 40%, 200g of tundish slag (formed after the added tundish covering agent melts and absorbs inclusions) is taken from the tundish casting area to test the CaO and TiO2 contents of the tundish slag.2C =23.17%, w 2T =10.54%;

[0042] (4) Calculate the weight of CaO covering agent before use, recorded as W 1CaO , W 1CaO =W1×w 1C =160kg×30.75%=49.2kg;

[0043] (5) Calculate the ratio of TiO2 to CaO content in the slag of the last batch of tundish casting (R = w) 2T / w 2C =10.54% / 23.17%=0.45;

[0044] (6) Since a retaining wall is usually installed between the tundish casting area and the impact area, it can effectively prevent the slag (containing CaO) from the ladle from flowing to the casting area. At the same time, the refractory in the casting area does not contain CaO. Therefore, it can be considered that the mass of CaO in the tundish covering agent added to the casting area is conserved. Based on this, the weight of TiO2 in the tundish slag in the casting area when the tundish is cast for the last batch can be quantitatively calculated. 2TiO2 =W 1CaO ×R=49.2kg×0.45=22.14kg;

[0045] Since the main materials of the refractory materials in the casting area of ​​the tundish are MgO-C and Al2O3-C, which do not contain TiO2, the TiO2 in the tundish slag can be considered to come from the titanium-containing molten steel. 2TiO2 =22.14kg is the weight of TiO2 inclusions in molten steel that floats up into the tundish slag.

[0046] In order to verify the accuracy of the calculation method, during the production process of the example, steel samples were taken from the impact zone and casting zone of each furnace. The average total Ti content of the steel samples in the impact zone was 0.0401%, and the average total Ti content of the steel samples in the casting zone was 0.0395%. The total weight of molten steel from all furnaces was 2171 tons. The weight of Ti element loss in the molten steel from the impact zone to the casting zone was △W. Ti =2171×1000×(0.0401%-0.0395%)=13.026kg. The lost Ti element forms TiO2 inclusions which are adsorbed and removed by the tundish slag. Based on the conservation of Ti element mass, the actual weight of TiO2 adsorbed and removed by the tundish slag can be determined as W' 2TiO2 =13.026×80 / 48=21.71kg, where "80" is the relative atomic weight of TiO2 and "48" is the relative atomic weight of Ti.

[0047] Compare the calculation results W in the embodiment of the present application 2TiO2 =22.14kg and the measured result W' 2TiO2=21.71kg, it can be seen that the difference between the two is only 0.43kg, corresponding to a relative error of 2.0, indicating that the calculation method provided in this application has good accuracy.

[0048] The above embodiments are only used to help understand the method and core idea of ​​the present invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

[0049] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for calculating the amount of TiO2 inclusions removed in the ladle casting zone during the continuous casting process of titanium-containing steel, comprising the following steps: S1) Detect the CaO content of the middle package covering agent before use, denoted as w 1C , wt%; S2) continuously casting the titanium-containing molten steel, pouring the first furnace of the tundish, adding the tundish covering agent into the tundish casting area, and the added weight of the tundish covering agent is recorded as W1, kg; In the last batch of tundish casting, the contents of CaO and TiO2 in the tundish slag were detected and recorded as w 2C 、w 2T , wt%; S3) Calculate the weight of CaO in the middle package covering agent, recorded as W 1CaO , W 1CaO =W1×w 1C , kg; Calculate the content ratio of TiO2 and CaO in the tundish slag, denoted as R, R = w 2T / w 2C ; S4) According to the CaO mass conservation law, the weight of TiO2 in the tundish slag is recorded as W 2TiO2 , W 2TiO2 =W 1CaO ×R,kg.

2. The calculation method according to claim 1, characterized in that: The middle package covering agent does not contain TiO2.

3. The calculation method according to claim 1, characterized in that: In step S1), the detected amount of the middle package covering agent is ≥100g.

4. The calculation method according to claim 1 or 2, characterized in that: In step S1), the detected amount of the middle package covering agent is 200-300 g.

5. The calculation method according to claim 1, characterized in that: In step S2), the timing of adding the tundish covering agent is: the weight of the molten steel in the tundish reaches 40-60wt% of the nominal capacity.

6. The calculation method according to claim 1, characterized in that: In step S2), the timing for detecting the tundish slag is when the weight of the molten steel in the large ladle remains 30-50wt%.

7. The calculation method according to claim 1, characterized in that: In step S2), the detected amount of the middle ladle slag is ≥100g.

8. The calculation method according to claim 1, characterized in that: In step S2), the detected amount of the tundish slag is 200-300 g.

9. Application of the calculation method according to any one of claims 1 to 8 in the design of a middle package covering agent.