Electrified weir plate of tundish and method for removing inclusions of electrified weir plate

Abstract

The invention discloses an electrified weir plate of a tundish and a method for removing inclusions of the electrified weir plate. The electrified weir plate comprises an electrified weir plate body, a power supply and a conductive structure, the conductive structure is arranged on the electrified weir plate body; the power supply is connected with the conductive structure through a cable; the electrified weir plate body is arranged between a long nozzle and a submersed nozzle of the tundish; the section shape of the electrified weir plate body is matched with the section shape of the through steel of the tundish; and a steel through hole is formed in the bottom of the electrified weir plate body. According to the invention, non-metallic inclusions in tundish molten steel can be effectively removed, and the inclusions are prevented from entering a crystallizer along with the molten steel to influence the final quality of a casting blank.

Description

Technical Field

[0001] The invention relates to a high-quality steel continuous casting technology, and more specifically to an electrified weir plate of a tundish and a method for removing inclusions therefrom. Background Art

[0002] In high-quality steel products, especially in the production of automotive plates and other products, there are extremely high requirements for the purity and surface quality of molten steel. Therefore, all aspects of molten steel pollution that may be caused in steelmaking and continuous casting production must be strictly controlled. In the production process of high-quality steel, molten iron from the blast furnace is smelted and refined into qualified molten steel, which is poured from the ladle into the continuous casting tundish, flows through the tundish, poured into the crystallizer, and finally solidified into qualified ingots.

[0003] However, the closer the large non-metallic inclusions are to the crystallizer, the more difficult it is to remove them. Inclusions that are not removed will enter the crystallizer with the steel flow, and form oxide inclusion steel defects in the ingot after solidification, which will cause greater damage to the steel quality of the ingot and seriously affect the final quality of the ingot.

[0004] The main way to remove inclusions in the continuous casting process is to promote the floating removal of non-metallic inclusions by optimizing the molten steel flow field in the tundish. Summary of the invention

[0005] In view of the defects existing in the prior art, the purpose of the present invention is to provide an electrified weir plate of a tundish and a method for removing inclusions therefrom, which can effectively remove non-metallic inclusions in the molten steel in the tundish and prevent the inclusions from entering the crystallizer with the molten steel and affecting the final quality of the ingot.

[0006] To achieve the above object, the present invention adopts the following technical solution:

[0007] A first aspect of the present invention provides an electrified weir plate of a tundish, comprising an electrified weir plate body, a power source and a conductive structure;

[0008] The conductive structure is arranged on the energized weir plate body;

[0009] The power source is connected to the conductive structure via a cable;

[0010] The electrified weir plate body is arranged between the long water inlet and the submerged water inlet of the tundish;

[0011] The cross-sectional shape of the electrified weir plate body is adapted to the cross-sectional shape of the through steel of the tundish;

[0012] A through steel hole is provided at the bottom of the electrified weir plate body.

[0013] Preferably, the conductive structure includes a conductive hook and a ceramic conductive element;

[0014] The ceramic conductive elements have a pair, symmetrically located on two sides of the through steel hole;

[0015] The conductive hooks are provided in a pair, symmetrically arranged on the top of the energized weir plate body, respectively connected to the corresponding ceramic conductive elements, and also respectively connected to the positive and negative electrodes of the power supply through the cables.

[0016] Preferably, the material composition of the ceramic conductive element includes the following components by mass percentage:

[0017] C: 20-35%;

[0018] Al 2 O 3 : 45~60%;

[0019] SiO 2 :6~12%.

[0020] Preferably, the volume density of the ceramic conductive element is ≥2.4 g / cm 3 , apparent porosity ≤19%, flexural strength ≥5.5MPa, compressive strength ≥40MPa.

[0021] Preferably, the material of the electrified weir plate body is:

[0022] MgO≥75wt%,Fe 2 O 3 ≤2wt%.

[0023] Preferably, the volume density of the electrified weir plate body is ≥2.75g / cm 3 , flexural strength ≥5.0MPa, compressive strength ≥40MPa.

[0024] The second aspect of the present invention provides a method for removing inclusions from the electrified weir plate of the tundish provided in the first aspect of the present invention, comprising the following steps:

[0025] S1, the electrified weir plate body is arranged between the long water inlet and the submerged water inlet of the tundish, and the ceramic conductive element is connected to the positive and negative electrodes of the power supply to form a conductive circuit;

[0026] S2, opening the slide plate of the ladle, the molten steel flows into the tundish from the long water inlet, and then flows through the steel through hole. Under the action of the conductive loop formed by the ceramic conductive element, the non-metallic inclusions in the molten steel gather toward the negative electrode, thereby achieving the purpose of removing the non-metallic inclusions;

[0027] S3. The molten steel after the non-metallic inclusions are removed enters the crystallizer through the submerged water inlet.

[0028] Preferably, the flow rate of the molten steel is 2-10 t / min.

[0029] Preferably, the voltage of the power supply is 2-30V, and the current is 10-350A.

[0030] Preferably, the current of the power supply is adjusted as follows:

[0031] I=1800*Q / U

[0032] In the formula, I is the current, unit is A; Q is the steel throughput, unit is t / min; U is the voltage, unit is V.

[0033] The energized weir plate of a tundish and a method for removing inclusions provided by the present invention have the following beneficial effects:

[0034] 1) The electrified weir plate of the tundish of the present invention has a simple structure, is safe and reliable in use, and has no impact on the smooth production and safety;

[0035] 2) The ceramic conductive element in the energized weir plate of the tundish of the present invention has good conductivity, does not pollute the molten steel, is resistant to corrosion and thermal shock, and ensures that the service life is synchronized with the tundish weir plate;

[0036] 3) The method for removing inclusions from the electrified weir plate of the tundish of the present invention uses a safe voltage, and the current can be adjusted with the amount of steel passing through and the voltage. It can effectively remove non-metallic inclusions in the molten steel in the tundish, and prevent the inclusions from entering the crystallizer with the molten steel and affecting the quality of the final ingot. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a schematic structural diagram of the electrified weir plate of the present invention;

[0038] Figure 2 yes Figure 1 Side view of. DETAILED DESCRIPTION

[0039] In order to better understand the above technical solution of the present invention, the technical solution of the present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0040] Combination Figure 1 and Figure 2 As shown, an electrified weir plate of a tundish provided by the present invention comprises an electrified weir plate body 1, a power source 2 and a conductive structure.

[0041] The conductive structure is installed on the energized weir plate body 1 .

[0042] The power source 2 is electrically connected to the conductive structure via a cable 3 .

[0043] The cross-sectional shape of the electrified weir plate body 1 is adapted to the cross-sectional shape of the through steel of the tundish, and a through steel hole 4 is provided at the bottom. The electrified weir plate body 1 is arranged between the long water inlet and the submerged water inlet of the tundish, and the molten steel can only flow through the through steel hole 4.

[0044] The conductive structure includes a conductive hook 5 and a ceramic conductive element 6 .

[0045] There is a pair of ceramic conductive elements 6 symmetrically located on two side surfaces of the through-steel hole 4 , forming positive and negative poles on the two side surfaces of the through-steel hole 4 .

[0046] There is a pair of conductive hooks 5 symmetrically arranged on the top of the electrified weir plate body 1 , which are respectively connected to corresponding ceramic conductive elements 6 , and are also respectively connected to the positive and negative electrodes of the power source 2 through the cable 3 .

[0047] The material composition of the ceramic conductive element 6 includes the following components by mass percentage:

[0048] C: 20-35%;

[0049] Al 2 O 3 : 45~60%;

[0050] SiO 2 :6~12%.

[0051] The C content of the ceramic conductive element 6 is 20-35%. Such a C content makes the C in the material form a continuous distribution state to ensure that the resistivity is less than 0.5×10-4Ω·m, and the function and efficiency of the applied electric field are particularly guaranteed. In addition, if the C content is too high, the strength of the ceramic conductive element 6 is low, and the anti-erosion performance of the molten steel and slag liquid in the tundish is reduced, and a good service life cannot be guaranteed.

[0052] The volume density of the ceramic conductive element 6 is ≥ 2.4 g / cm 3 , apparent porosity ≤19%, flexural strength ≥5.5MPa, compressive strength ≥40MPa.

[0053] The ceramic conductive element 6 is characterized by good conductivity, no pollution to molten steel, corrosion resistance, thermal shock resistance, and ensuring synchronization of service life with the energized weir plate body 1.

[0054] The ceramic conductive element 6 is isostatically pressed and pre-made into a long strip shape (the same as the plug rod production method). When the energized weir plate body 1 is cast, it is pre-embedded and placed in the designed position of the weir plate mold to be integrated into an energized weir plate body 1 as a whole.

[0055] The materials of the electrified weir plate body 1 include:

[0056] MgO≥75wt%,Fe2 O 3 ≤2wt%.

[0057] The volume density of the electrified weir plate body 1 is ≥2.75g / cm 3 , flexural strength ≥5.0MPa, compressive strength ≥40MPa.

[0058] The second aspect of the present invention provides a method for removing inclusions from an electrified weir plate of a tundish provided in the first aspect of the present invention, comprising the following steps:

[0059] S1, the electrified weir plate body 1 is placed between the long water inlet and the submerged water inlet of the tundish, and the ceramic conductive element 6 is connected to the positive and negative electrodes of the power supply 2 through the cable 3 to form a conductive circuit;

[0060] S2, open the slide plate of the ladle, the molten steel flows into the tundish from the long water inlet, and then flows through the steel through hole 4, and the non-metallic inclusions in the molten steel also flow through the steel through hole 4 with the molten steel. Since the non-metallic inclusions carry positive charges, under the action of the conductive loop formed by the ceramic conductive element 6, the non-metallic inclusions in the molten steel gather toward the negative electrode of the ceramic conductive element 6, thereby achieving the purpose of removing the non-metallic inclusions;

[0061] S3. The molten steel with non-metallic inclusions removed enters the crystallizer through the submerged water inlet.

[0062] The flow rate of molten steel is 2 to 10 t / min.

[0063] The voltage of power supply 2 is 2 to 30V, and the current is 10 to 350A.

[0064] Among them, the voltage of power supply 2 is generally set to a fixed value, and the current process parameters of power supply 2 are adjusted with the changes in voltage and steel throughput. The calculation formula for current parameter adjustment is as follows:

[0065] I=1800*Q / U

[0066] In the formula, I is the current, unit is A; Q is the steel throughput, unit is t / min; U is the voltage, unit is V.

[0067] Example 1

[0068] This embodiment is used in a 60t double-flow tundish. The shape of the electrified weir plate body 1 is consistent with the through-steel section of the 60t tundish, and a through-steel hole 4 is opened at the bottom of the electrified weir plate body 1. Two electrified weir plate bodies 1 are placed in the middle of the long water inlet of the tundish and the submerged water inlets on both sides. The molten steel injected into the long water inlet can only flow through the through-steel holes 4 of the electrified weir plate bodies 1 on both sides and immerse into the submerged water inlets. A conductive hook 5 is provided on the upper part of each electrified weir plate body 1, and a ceramic conductive element 6 is connected to the lower part of the conductive hook 5. The ceramic conductive element 6 is directly connected to the two sides of the through-steel hole 4, forming positive and negative electrodes on the two sides of the through-steel hole 4. The conductive hook 5 is connected to the positive and negative electrodes of the DC power supply 2 by the cable 3.

[0069] The chemical composition of the ceramic conductive element 6 is as follows:

[0070] C: 35%;

[0071] Al 2 O 3 : 58%;

[0072] SiO 2 : 7%.

[0073] Physical properties: Bulk density: 2.80g / cm 3 , apparent porosity: 16%, flexural strength: 6MPa, compressive strength: 50MPa, resistivity: 0.2×10~4Ω·m.

[0074] Features: Good electrical conductivity, especially guaranteed function and efficiency of applied electric field, no pollution to molten steel, corrosion resistance, thermal shock resistance, guaranteed to be synchronized with the service life of the energized weir plate body 1.

[0075] The ceramic conductive element 6 is isostatically pressed and pre-made into a long strip shape (the same as the plug rod production method). When the powered weir plate body 1 is cast, it is pre-embedded and placed in the designed position of the mold of the powered weir plate body 1, and is integrated into an integrated powered weir plate body 1.

[0076] Physical and chemical performance requirements of the material of the electrified weir plate body 1:

[0077] MgO: 80%;

[0078] Fe2O3: 2.0%;

[0079] Bulk density: 2.75g / cm 3 , compressive strength: 50MPa, flexural strength: 6.0MPa.

[0080] The inclusion removal method based on the energized weir plate of this embodiment includes the following steps:

[0081] 1. Preparation before pouring

[0082] The electrified weir plate body 1 is arranged between the long water inlet and the submerged water inlet of the tundish, and the ceramic conductive element 6 is connected to the positive and negative electrodes of the DC power supply 2 by the cable 3 .

[0083] 2. Molten steel pouring

[0084] The slide plate of the ladle is opened, and the single-flow steel pouring rate is controlled at 3t / min. The molten steel in the ladle flows into the tundish from the long water inlet, flows through the steel through-hole 4 of the electrified weir plate body 1, and enters the crystallizer through the immersion water inlet.

[0085] 3. Inclusion removal process of the electrified weir plate body 1

[0086] The DC power supply is turned on, the voltage of the ceramic conductive element 6 is set at 24V, and the current is set at 300A. The voltage is generally set to a fixed value, and the current process parameters are adjusted with the changes in voltage and steel throughput. The calculation formula for current parameter adjustment is as follows:

[0087] I=1800*Q / U

[0088] I-current A, Q-steel throughput t / min, U-voltage V

[0089] The molten steel passes through the steel through hole 4, and a conductive loop is formed between the positive and negative electrodes formed by the two ceramic conductive elements 6 on the side walls of the steel through hole 4. Non-metallic inclusions in the molten steel also flow through the steel through hole 4 with the molten steel. Since the non-metallic inclusions carry positive charges, under the action of the conductive loop formed by the two ceramic conductive elements 6 on the side walls of the steel through hole 4, the non-metallic inclusions migrate to the negative electrode of the ceramic conductive element 6, and finally gather and adsorb on the negative electrode, thereby achieving the purpose of removing non-metallic inclusions in the molten steel.

[0090] Example 2

[0091] This embodiment is used in a 60t double-flow tundish. The shape of the electrified weir plate body 1 is consistent with the through-steel section of the 60t tundish, and a through-steel hole 4 is opened at the bottom of the electrified weir plate body 1. Two electrified weir plate bodies 1 are placed in the middle of the long water inlet of the tundish and the submerged water inlets on both sides. The molten steel injected into the long water inlet can only flow through the through-steel holes 4 of the electrified weir plate bodies 1 on both sides and immerse into the submerged water inlets. A conductive hook 5 is provided on the upper part of each electrified weir plate body 1, and a ceramic conductive element 6 is connected to the lower part of the conductive hook 5. The ceramic conductive element 6 is directly connected to the two sides of the through-steel hole 4, forming positive and negative electrodes on the two sides of the through-steel hole 4. The conductive hook 5 is connected to the positive and negative electrodes of the DC power supply 2 by the cable 3.

[0092] The chemical composition of the ceramic conductive element 6 is as follows:

[0093] C: 35%;

[0094] Al2O3: 58%;

[0095] SiO2:7%.

[0096] Physical properties: Bulk density: 2.80g / cm3, apparent porosity: 16%, flexural strength: 6MPa, compressive strength: 50MPa, resistivity: 0.2×10~4Ω·m.

[0097] Features: Good electrical conductivity, especially guaranteed function and efficiency of applied electric field, no pollution to molten steel, corrosion resistance, thermal shock resistance, guaranteed to be synchronized with the service life of the energized weir plate body 1.

[0098] The ceramic conductive element 6 is isostatically pressed and pre-made into a long strip shape (the same as the plug rod production method). When the powered weir plate body 1 is cast, it is pre-embedded and placed in the designed position of the mold of the powered weir plate body 1, and is integrated into an integrated powered weir plate body 1.

[0099] Physical and chemical performance requirements of the material of the electrified weir plate body 1:

[0100] MgO: 80%;

[0101] Fe2O3: 2.0%;

[0102] Bulk density: 2.75g / cm3, compressive strength: 50MPa, flexural strength: 6.0MPa.

[0103] The inclusion removal method based on the energized weir plate of this embodiment includes the following steps:

[0104] 1. Preparation before pouring

[0105] The electrified weir plate body 1 is arranged between the long water inlet and the submerged water inlet of the tundish, and the ceramic conductive element 6 is connected to the positive and negative electrodes of the DC power supply 2 by the cable 3 .

[0106] 2. Molten steel pouring

[0107] The slide plate of the ladle is opened, and the single-flow steel pouring rate is controlled at 3t / min. The molten steel in the ladle flows into the tundish from the long water inlet, flows through the steel through-hole 4 of the electrified weir plate body 1, and enters the crystallizer through the immersion water inlet.

[0108] 3. Inclusion removal process of the electrified weir plate body 1

[0109] The DC power supply is turned on, the voltage of the ceramic conductive element 6 is set at 5V, and the current is set at 100A. The voltage is generally set to a fixed value, and the current process parameters are adjusted with the changes in voltage and steel throughput. The calculation formula for current parameter adjustment is as follows:

[0110] I=1800*Q / U

[0111] I-current A, Q-steel throughput t / min, U-voltage V

[0112] The molten steel passes through the steel through hole 4, and a conductive loop is formed between the positive and negative electrodes formed by the two ceramic conductive elements 6 on the side walls of the steel through hole 4. Non-metallic inclusions in the molten steel also flow through the steel through hole 4 with the molten steel. Since the non-metallic inclusions carry positive charges, under the action of the conductive loop formed by the two ceramic conductive elements 6 on the side walls of the steel through hole 4, the non-metallic inclusions migrate to the negative electrode of the ceramic conductive element 6, and finally gather and adsorb on the negative electrode, thereby achieving the purpose of removing non-metallic inclusions in the molten steel.

[0113] Those skilled in the art should recognize that the above embodiments are only used to illustrate the present invention, and are not intended to limit the present invention. As long as they are within the spirit of the present invention, any changes or modifications to the above embodiments will fall within the scope of the claims of the present invention.

Claims

1. An electrified weir plate for a tundish, characterized in that: It includes an electrified weir plate body, a power source and a conductive structure; The conductive structure is arranged on the energized weir plate body; The power source is connected to the conductive structure via a cable; The electrified weir plate body is arranged between the long water inlet and the submerged water inlet of the tundish; The cross-sectional shape of the electrified weir plate body is adapted to the cross-sectional shape of the through steel of the tundish; A through steel hole is provided at the bottom of the electrified weir plate body.

2. The electrified weir plate of the tundish according to claim 1, characterized in that: The conductive structure includes a conductive hook and a ceramic conductive element; The ceramic conductive elements have a pair, symmetrically located on two sides of the through steel hole; The conductive hooks are provided in a pair, symmetrically arranged on the top of the energized weir plate body, respectively connected to the corresponding ceramic conductive elements, and also respectively connected to the positive and negative electrodes of the power supply through the cables.

3. The electrified weir plate of the tundish according to claim 2, characterized in that: The material composition of the ceramic conductive element includes the following components by mass percentage: C：20～35％； Al2O3: 45-60%; SiO2: 6~12%.

4. The electrified weir plate of the tundish according to claim 3, characterized in that: The volume density of the ceramic conductive element is ≥2.4g / cm 3 , apparent porosity ≤19%, flexural strength ≥5.5MPa, compressive strength ≥40MPa.

5. The electrified weir plate of the tundish according to claim 2, characterized in that: The materials of the electrified weir plate body include: MgO≥75wt%, Fe2O3≤2wt%.

6. The electrified weir plate of the tundish according to claim 5, characterized in that: The volume density of the electrified weir plate body is ≥2.75g / cm 3 , flexural strength ≥5.0MPa, compressive strength ≥40MPa.

7. A method for removing inclusions from an electrified weir plate of a tundish according to any one of claims 1 to 6, characterized in that: The following steps are involved: S1, the electrified weir plate body is arranged between the long water inlet and the submerged water inlet of the tundish, and the ceramic conductive element is connected to the positive and negative electrodes of the power supply to form a conductive circuit; S2, opening the slide plate of the ladle, the molten steel flows into the tundish from the long water inlet, and then flows through the steel through hole. Under the action of the conductive loop formed by the ceramic conductive element, the non-metallic inclusions in the molten steel gather toward the negative electrode, thereby achieving the purpose of removing the non-metallic inclusions; S3. The molten steel after the non-metallic inclusions are removed enters the crystallizer through the submerged water inlet.

8. The method for removing inclusions according to claim 7, characterized in that: The flow rate of the molten steel is 2-10t / min.

9. The method for removing inclusions according to claim 8, characterized in that: The voltage of the power supply is 2-30V, and the current is 10-350A.

10. The method for removing inclusions according to claim 9, characterized in that: The current of the power supply is adjusted as follows: I=1800*Q / U In the formula, I is the current, unit is A; Q is the steel throughput, unit is t / min; U is the voltage, unit is V.

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