Method for calculating erosion amount of tundish lining in casting area of continuous casting tundish and application of method

Abstract

The invention provides a method for calculating the erosion amount of a tundish lining in a continuous casting tundish casting area. The method comprises the steps that S1, the content of MgO in the tundish lining and the content of CaO and MgO in a tundish covering agent before use are detected; s2, the molten steel is cast, a tundish is cast into a first furnace, and a tundish covering agent is added into a tundish casting area; the tundish is cast for the last furnace, the content of CaO and the content of MgO in tundish slag are detected, and the content ratio of the MgO to the CaO in the tundish slag is calculated; s3) obtaining the weight of MgO in the tundish slag according to the mass conservation of the tundish covering agent CaO in the casting area; the MgO increment in the ladle slag in the casting area in the casting process is calculated and is derived from ladle lining erosion, and therefore the ladle lining erosion amount of the casting area is calculated. According to the calculation method provided by the invention, the tundish lining erosion amount under different working conditions can be accurately calculated and evaluated, and a key data support is provided for optimizing continuous casting tundish refractory and a steel casting process.

Description

Technical Field

[0001] The invention relates to the technical field of metallurgy, and in particular to a method for calculating the erosion amount of a lining in a casting zone of a continuous casting tundish and an application thereof. Background Art

[0002] The tundish is an important metallurgical container for continuous casting machines, and plays an important metallurgical function such as diverting molten steel, purifying steel quality, and regulating molten steel temperature. During the steel casting process, the lining of the tundish is constantly eroded by melting. When the lining erosion reaches a certain level, the tundish needs to be taken offline and rebuilt. Therefore, optimizing the development of supporting tundish refractory materials and auxiliary materials, and inhibiting the erosion rate of the tundish lining have become important directions for achieving cost reduction and efficiency improvement of continuous casting tundishes. Accurately calculating and determining the erosion amount of the tundish lining under different working conditions is the key basis for optimizing the development of tundish refractory materials and auxiliary materials.

[0003] At present, the relevant patents for reducing the erosion of the lining of the tundish mainly focus on the optimization of the refractory materials, auxiliary materials and flow control devices of the tundish. For example: The Chinese patent with publication number CN105127385A discloses a synthetic slag for the tundish covering agent, which can avoid the secondary oxidation of the molten steel in the tundish, reduce the erosion of the refractory materials in the tundish, and improve the adsorption capacity of the covering agent for inclusions in the molten steel. The Chinese patent with publication number CN118237571A discloses an open-casting special tundish for threaded steel and its smelting method, which reduces the erosion of the molten steel on the tundish body and reduces the erosion of the tundish through the cooperation of the trough body, the impact cup, the short dam and the movable buffer mechanism. The Chinese patent with publication number CN118221444A discloses a magnesium dry material for the tundish and a preparation method, which is beneficial to the filling of the gaps between the magnesia sands by mixing the fused magnesia sands and the sintered magnesia sands, and can resist the penetration of the slag into the refractory materials. At the same time, the low melting point phase produced during the reaction is small, which improves the slag erosion resistance of the refractory materials. The Chinese patent with publication number CN118106482A discloses a method for improving the baking quality of the working layer of the tundish of a small billet continuous casting machine, which improves the baking quality by controlling the baking process of the working layer of the tundish in a standardized manner, prevents the working layer from cracking and embrittlement, and further prevents the occurrence of non-corrosion-resistant materials falling into the molten steel to affect product quality, block the water inlet, and fail to start pouring. The Chinese patent with publication number CN117862447A discloses a control method for increasing the number of continuous casting furnaces of the tundish of an ultra-high-speed continuous casting machine, which improves the production, baking, material, and production mode of the tundish, and through the improvement, the number of continuous casting furnaces of the tundish is increased by more than 6 furnaces compared with the previous improvement, and the continuous casting time is increased by more than 3 hours. The Chinese patent with publication number CN117550878A discloses a low-cost, long-life tundish slag line dry material, the prepared dry material has excellent corrosion resistance, and is relatively low in cost, and has a service life of more than 60 hours on the T-shaped billet tundish, and has a long service life.

[0004] Although the above patents disclose many process technologies and material optimization and improvement methods for reducing the erosion of the tundish lining, they do not propose how to accurately calculate and evaluate the erosion amount of the tundish lining during the steel casting process. Therefore, the above patents are still difficult to provide intuitive and reliable data support for related optimization and improvement work. Summary of the invention

[0005] The technical problem solved by the present invention is to provide a method for calculating the erosion amount of the lining of the casting area of ​​the continuous casting tundish. The calculation method provided in the present application can accurately calculate and evaluate the erosion amount of the lining of the continuous casting tundish.

[0006] In view of this, the present application provides a method for calculating the lining erosion amount of a casting area of ​​a continuous casting tundish, comprising the following steps:

[0007] S1) Detect the MgO content in the lining material of the tundish before use, denoted as w' M , wt%;

[0008] The contents of CaO and MgO in the middle package covering agent before use were respectively detected and recorded as w 1C 、w 1M , wt%;

[0009] S2) Casting the molten steel, pouring the first heat in the tundish, adding W1 kg of the tundish covering agent into the tundish casting area; calculating the weight of MgO and CaO respectively, and recording them as W 1CaO , W 1MgO , where W 1CaO =W1×w 1C , W 1MgO =W1×w 1M ;

[0010] After the last batch of tundish casting, the contents of CaO and MgO in the tundish slag were detected and recorded as w 2C 、w 2M , wt%, calculate the ratio of MgO to CaO in the tundish slag R2, R2 = w 2M / w 2C ;

[0011] S3) According to the mass conservation of CaO covering agent in the casting area, the weight W of MgO in the tundish slag is obtained. 2MgO =W 1CaO ×R2, kg;

[0012] Calculate the MgO increment ΔW in the slag ladle in the casting area during casting MgO =W 2MgO -W 1MgO The increase of MgO in the tundish slag comes from the lining erosion. The lining erosion amount W in the casting area is calculated. 包衬侵蚀 =ΔWMgO / w' M , kg.

[0013] Preferably, in step S1), the detected amount of the tundish lining material is ≥100 g.

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

[0015] 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.

[0016] Preferably, in step S2), the timing for respectively detecting the contents of CaO and MgO in the tundish slag is when the weight of the molten steel in the ladle remains 30-50wt%.

[0017] Preferably, in step S2), the detected amount of the middle ladle slag is ≥100g.

[0018] Preferably, in step S1), the w' M >80wt%.

[0019] Preferably, during the casting process, a retaining wall is provided between the tundish casting zone and the impact zone.

[0020] Preferably, in step S1), the middle package covering agent includes CaO, MgO, Al2O3, and SiO2.

[0021] The present application also provides the application of the calculation method in the design of tundish lining materials.

[0022] The present application provides a method for calculating the erosion amount of the lining of a casting area of ​​a continuous casting tundish, which first detects the weight of MgO in the lining material of the tundish before use and the contents of CaO and MgO in the tundish covering agent before use; then casts molten steel, starts pouring the first furnace of the tundish, adds a certain amount of tundish covering agent to the tundish casting area, calculates the weight of MgO and CaO therein, and respectively detects the contents of CaO and MgO in the tundish slag in the last furnace of tundish casting, and calculates the ratio of the two; then, according to the mass conservation of CaO in the tundish covering agent, the weight of MgO in the tundish slag is obtained; finally, the MgO increment in the tundish slag in the casting area during the casting process is calculated, and during the casting process, the stopper rod, retaining wall and other flow control devices in the tundish casting area do not contain MgO, therefore, the MgO increment in the tundish slag can be considered to be entirely derived from the lining erosion amount, and thus the MgO increment can be used to calculate the erosion weight of the tundish lining during the casting process. The calculation method provided in the present application is a calculation method for calibrating the amount of lining erosion in the casting area of ​​the continuous casting tundish during the steel pouring process based on the change in the MgO / CaO ratio of the tundish slag. It utilizes the mass conservation of CaO and the increase in MgO during the casting process to accurately calculate and evaluate the amount of lining erosion in the tundish, providing key data support for optimizing the continuous casting tundish refractory and steel pouring process. DETAILED DESCRIPTION

[0023] 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.

[0024] In view of the lack of a quantitative calibration calculation method for the amount of ladle lining erosion during steel casting in the prior art, the present application provides a method for calculating the amount of ladle lining erosion in the casting area of ​​a continuous casting tundish, which calculates the amount of lining erosion in the casting area of ​​a continuous casting tundish during steel casting based on the change in the MgO / CaO ratio of the tundish slag and the conservation of CaO mass. The calculation method can accurately calculate and evaluate the amount of tundish refractory erosion under different working conditions, and provides key data support for optimizing the continuous casting tundish refractory and steel casting process. Specifically, an embodiment of the present invention discloses a method for calculating the amount of lining erosion in the casting area of ​​a continuous casting tundish, comprising the following steps:

[0025] S1) Detect the MgO content in the lining material of the tundish before use, denoted as w' M , wt%;

[0026] The contents of CaO and MgO in the middle package covering agent before use were respectively detected and recorded as w 1C 、w 1M , wt%;

[0027] S2) Casting the molten steel, pouring the first heat in the tundish, adding W1 kg of the tundish covering agent into the tundish casting area; calculating the weight of MgO and CaO respectively, and recording them as W 1CaO , W 1MgO , where W 1CaO =W1×w 1C , W 1MgO =W1×w 1M ;

[0028] After the last batch of tundish casting, the contents of CaO and MgO in the tundish slag were detected and recorded as w 2C 、w 2M , wt%, calculate the ratio of MgO to CaO in the tundish slag R2, R2 = w 2M / w 2C ;

[0029] S3) According to the mass conservation of CaO covering agent in the casting area, the weight W of MgO in the tundish slag is obtained. 2MgO =W 1CaO ×R2;

[0030] Calculate the MgO increment ΔW in the slag ladle in the casting area during casting MgO =W 2MgO -W 1MgO The increase of MgO in the tundish slag comes from the lining erosion. The lining erosion amount W in the casting area is calculated. 包衬侵蚀 =ΔW MgO / w' M .

[0031] The calculation method provided in this application is aimed at calculating the amount of lining erosion in the casting area of ​​the continuous casting tundish during the casting process, and there is no special restriction on the type of steel; that is, the calculation method provided in this application has good applicability.

[0032] First, the present application detects the MgO content in the tundish lining material before use, which is denoted as w' M , wt%; wherein the detected amount of the tundish lining material is ≥100g, specifically, the detected amount of the tundish lining material is 200-300g. The present application also detects the contents of CaO and MgO in the tundish covering agent before use, respectively, and records them as w 1C 、w 1M , wt%. In the present application, the main component of the tundish lining material is MgO, and it also contains a small amount of SiO2, Al2O3 and other components, wherein the content of MgO is greater than 80wt%. In a specific embodiment, the content of MgO is 87-95wt%. The main components of the tundish covering agent are CaO, Al2O3, MgO, and it contains a small amount of SiO2.

[0033] The molten steel is cast, and 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, a certain amount of tundish covering agent is added to the tundish casting area and other areas. The amount of the tundish covering agent added is recorded as W1 kg; specifically, the timing of adding the tundish covering agent is when the weight of the molten steel in the tundish reaches 45-55wt% of the nominal capacity. On this basis, the contents of MgO and CaO in the above-mentioned added tundish covering agent are calculated, respectively, and recorded as W 1CaO , W 1MgO , where W 1CaO =W1×w 1C , W 1MgO =W1×w 1M .

[0034] In the last batch of tundish casting, preferably when the weight of the molten steel in the large ladle is 30-50wt% remaining, the tundish slag is taken in the tundish casting area. The tundish slag is formed after the tundish covering agent melts and absorbs inclusions. The CaO and MgO contents in the tundish slag are detected and recorded as w 2C 、w 2M , wt%, and the content ratio of CaO and MgO in the tundish slag is calculated accordingly R2=w 2M / w 2C Specifically, the detection time of the middle ladle slag is when the weight of the large ladle molten steel remains 35-45wt%. The detection amount of the middle ladle slag is ≥100g, specifically, the detection amount of the middle ladle slag is 200-300g.

[0035] 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 material in the casting does not contain CaO. Therefore, it can be considered that the mass of CaO in the tundish covering agent in the casting area is conserved, that is, the mass of CaO in the tundish covering agent and the tundish slag remains unchanged. Based on this, the weight of MgO in the tundish slag in the casting area when the tundish is cast for the last batch can be quantitatively calculated. 2MgO =W 1CaO ×R2,kg.

[0036] Based on the above calculation, calculate the increment ΔW of MgO in the tundish slag relative to the tundish covering agent during the steel casting process. MgO , ΔW MgO =W 2MgO -W 1MgO .

[0037] Since the main component of the tundish lining material is MgO (reaching more than 80%), and during the steel casting process, the flow control devices such as the stopper rod, retaining wall, and retaining dam in the tundish casting area are generally made of Al2O3-C and do not contain MgO; therefore, the MgO increment in the tundish slag can be considered to be entirely derived from the lining erosion. The erosion weight of the tundish lining during the casting process is W包衬侵蚀 =ΔW MgO / w' M , kg.

[0038] The present application also provides the application of the above-mentioned calculation method in the design of the lining material of the intermediate ladle; the design can be the design of the material of the lining material, or the design of the structure of the lining material, and the present application does not impose any special restrictions on this.

[0039] This application proposes for the first time a calibration calculation method for the lining erosion in the casting area of ​​the continuous casting tundish during the steel pouring process based on the change in the MgO / CaO ratio of the tundish slag, which can effectively solve the current research deficiencies and fill the research gap in the calibration calculation method of the lining erosion. The calculation method provided in this application can quickly and accurately calculate and evaluate the erosion of the long nozzle based on the relevant component detection data of the production process, without affecting the normal production process, and can provide data support for optimizing the refractory and steel pouring process of the continuous casting tundish, thereby reducing the cost of tundish steel pouring, while helping to improve the cleanliness of molten steel and reduce the loss of inclusion defects. It is expected to create an annual benefit of at least 1 million yuan.

[0040] In order to further understand the present invention, the calculation method of the erosion amount of the casting zone lining of the continuous casting tundish provided by the present invention is described in detail below in conjunction with the embodiments. The protection scope of the present invention is not limited by the following embodiments.

[0041] Example Calculation of the lining erosion weight in the casting area of ​​the tundish after continuous casting of 10 furnaces of ultra-low carbon steel in a two-stream 70-ton tundish

[0042] (1) Take 150g of the middle bag lining material before use and detect and analyze its MgO content w' M =87%;

[0043] (2) Take 200g of the middle package covering agent before use and detect and analyze its CaO and MgO contents, which are w 1C =30.75%, w 1M =10.5%;

[0044] (3) Calculate the ratio of MgO to CaO content in the covering agent before use R1 = w 1M / w 1C =10.5% / 30.75%=0.34;

[0045] (4) When pouring steel, the first heat of the tundish is poured. When the weight of the molten steel in the tundish reaches 60% of the nominal capacity, a certain amount of tundish covering agent is added to the tundish casting area and other areas. The weight of the tundish covering agent added is W1 = 160 kg.

[0046] (5) In the last batch of tundish casting, when the weight of the molten steel in the large ladle remains at 35%, 150 g of tundish slag (the tundish slag formed by the melting of the added tundish covering agent) is taken from the tundish casting area to test the CaO and MgO contents of the tundish slag, which are w 2C =23.17%, w 2M =18.06%;

[0047] (6) Calculate the weight of CaO and MgO covering agents before use, respectively recorded as W 1CaO , W 1MgO , where W 1CaO =W1×w 1C =160kg×30.75%=49.2kg, W 1MgO =W1×w 1M =160kg×10.5%=16.8kg;

[0048] (7) Calculate the ratio of MgO to CaO in the slag of the last batch of tundish casting R2 = w 2M / w 2C =18.06% / 23.17%=0.78;

[0049] (8) 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 material in the casting 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 MgO in the tundish slag in the casting area when the tundish is cast for the last batch can be quantitatively calculated. 2MgO =W 1CaO ×R2=49.2kg×0.78=38.4kg;

[0050] (9) Calculation of the MgO increment ΔW in the slag ladle during steel casting MgO =W 2MgO -W 1MgO =38.4kg-16.8kg=21.6kg.

[0051] (10) Since the main component of the tundish lining material is MgO (reaching more than 80%), and during the steel casting process, the material of the flow control devices such as the stopper rod, retaining wall, and dam in the casting area of ​​the tundish is generally Al2O3-C, which does not contain MgO; therefore, the increase in MgO in the tundish slag can be considered to be entirely derived from the lining erosion. The erosion weight of the tundish lining during the casting process is W 包衬侵蚀 =ΔW MgO / w' M =21.6kg / 87%=24.8kg.

[0052] In order to verify the accuracy of the calculation method of the present application, the weight of the dry material in the casting area of ​​the ladle in the embodiment before and after use was compared; in the embodiment, before the ladle was put into use, the weight of the dry material used in the casting area of ​​the knotted ladle was weighed to be 315.4 kg, and after the ladle was used and unloaded, the weight of the dry material in the casting area of ​​the ladle that was not eroded was weighed again to be 291.2 kg, that is, the eroded weight of the dry material in the casting area during the use of the ladle was 315.4-291.2=24.2 kg. Compared with the actual measured erosion weight of 24.2 kg, the calculated result of 24.8 kg differed by only 0.6 kg, with a small deviation, indicating that the calculation method provided by the present application has a high calculation accuracy.

[0053] 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.

[0054] 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 lining erosion amount of a continuous casting tundish casting area, comprising the following steps: S1) Detect the MgO content in the lining material of the tundish before use, denoted as w' M , wt%; The contents of CaO and MgO in the middle package covering agent before use were respectively detected and recorded as w 1C 、w 1M , wt%; S2) Casting the molten steel, pouring the first furnace of the tundish, adding W1kg of the tundish covering agent to the tundish casting area; calculating the weight of MgO and CaO respectively, and recording them as W 1CaO , W 1MgO , where W 1CaO =W1×w 1C , W 1MgO =W1×w 1M ; After the last batch of tundish casting, the contents of CaO and MgO in the tundish slag were detected and recorded as w 2C 、w 2M , wt%, calculate the ratio of MgO to CaO in the tundish slag R2, R2 = w 2M / w 2C ; S3) According to the mass conservation of CaO covering agent in the casting area, the weight W of MgO in the tundish slag is obtained. 2MgO =W 1CaO ×R2, kg; Calculate the MgO increment ΔW in the slag ladle in the casting area during casting MgO =W 2MgO -W 1MgO The increase of MgO in the tundish slag comes from the lining erosion. The lining erosion amount W in the casting area is calculated. 包衬侵蚀 =ΔW MgO / w' M , kg.

2. The calculation method according to claim 1, characterized in that: In step S1), the detected amount of the tundish lining material is ≥100g.

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, 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.

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

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

7. The calculation method according to claim 1, characterized in that: In step S1), the w' M >80wt%.

8. The calculation method according to claim 1, characterized in that: During the casting process, a retaining wall is arranged between the tundish casting area and the impact area.

9. The calculation method according to claim 1, characterized in that: In step S1), the middle package covering agent includes CaO, MgO, Al2O3, and SiO2.

10. Application of the calculation method according to any one of claims 1 to 9 in the design of tundish lining materials.