A steel continuous casting composite electromagnetic stirrer

Abstract

The utility model discloses a kind of steel continuous casting composite electromagnetic stirrers, including one non-magnetic shell and inner tube, iron core is arranged between shell and inner tube;A group of rotating coils is wound on iron core, for passing into multiphase alternating current to generate rotating magnetic field;A group of traveling wave coils is embedded in iron core, for passing into multiphase alternating current to generate axial traveling wave magnetic field;Continuous casting billet passes from inner tube, the magnetic field generated after the electrification of rotating coil and traveling wave coil can carry out composite electromagnetic stirring to the unfrozen steel liquid in continuous casting billet.The device can simultaneously exert rotating stirring force and axial electromagnetic thrust on molten steel by integrating two kinds of coils in the same iron core, thereby comprehensively improving molten steel flow and feeding effect, effectively reducing center segregation, porosity and shrinkage cavity defects, and improving the internal quality of high-end billets such as high alloy steel.

Description

Technical Field

[0001] This utility model relates to the field of continuous casting technology in iron and steel metallurgy, and more specifically, to a composite electromagnetic stirrer for continuous casting of iron and steel. Background Technology

[0002] In the continuous casting process of square and round billets in iron and steel metallurgy, electromagnetic stirring is a key piece of equipment. It applies electromagnetic force at different stages of solidification of the molten metal within the continuously cast billet to stir the undried steel, thereby improving the internal quality of the billet. Currently, electromagnetic stirrers based on rotating magnetic fields are widely used. The rotational force generated by these stirrers causes the molten steel to move in a circular motion, which has a certain effect on expanding the equiaxed crystal zone and improving internal quality.

[0003] However, existing single-rotation magnetic field stirring methods have limitations. For certain high-quality steel grades, especially high-alloy steels, single-rotation stirring is insufficient to achieve precise control over the flow pattern of molten steel, and its effectiveness in promoting central feeding of the billet, effectively eliminating central porosity, and mitigating central segregation is limited. Although existing technologies have proposed some improvement schemes, such as combining time-varying magnetic field devices with rotary magnetic field stirrers, their structures and operating methods still fail to achieve a deep integration and synergistic effect between rotational force and axial feeding force.

[0004] Therefore, there is an urgent need in this field for a new type of electromagnetic stirrer that can simultaneously generate magnetic fields of different shapes to apply multi-dimensional electromagnetic forces to molten steel, thereby more effectively controlling the flow and solidification process of molten steel to meet the stringent requirements of high-end steel grades for billet quality. Utility Model Content

[0005] In view of the above-mentioned technical problems in related technologies, this utility model proposes a composite electromagnetic stirrer for continuous casting of steel, which can overcome the above-mentioned shortcomings of the prior art.

[0006] To achieve the above-mentioned technical objectives, the technical solution of this utility model is implemented as follows: A composite electromagnetic stirrer for continuous steel casting includes a non-magnetic outer shell and an inner cylinder, with an iron core disposed between the outer shell and the inner cylinder. A set of rotating coils is wound on the iron core for generating a rotating magnetic field by passing multiphase alternating current through it. A set of traveling wave coils is embedded in the iron core for generating an axial traveling wave magnetic field by passing multiphase alternating current through it. The continuously cast billet passes through the inner cylinder, and the magnetic fields generated by the rotating coils and the traveling wave coils can perform composite electromagnetic stirring on the unsolidified molten steel inside the continuously cast billet.

[0007] Furthermore, the rotating coil is wound on the toothed part of the iron core, and the number of rotating coils is a multiple of 2 or 3. The rotating coil is connected in a star or delta configuration, and generates a rotating magnetic field after two-phase or three-phase alternating current is applied.

[0008] Furthermore, the traveling wave coil is a solenoid winding, and the number of traveling wave coils is a multiple of 2 or 3, arranged along the axis. The traveling wave coils are connected in a star or delta configuration, and generate an axial traveling wave magnetic field after two-phase or three-phase alternating current is applied.

[0009] Furthermore, the rotating coil and the traveling wave coil are wound with hollow copper tubes or with sintered wire.

[0010] Furthermore, the outer shell and the inner cylinder are respectively provided with a front end plate and a rear end plate at both ends, which together form a sealed cavity.

[0011] Furthermore, a non-magnetic bracket is provided between the continuously cast billet and the inner cylinder, and there is a gap between the continuously cast billet and the non-magnetic bracket.

[0012] Furthermore, the housing is provided with a terminal box for connecting the rotating coil and the traveling wave coil to an external power supply.

[0013] Furthermore, the outer casing is provided with inlet and outlet water pipes for connecting cooling water.

[0014] The beneficial effects of this invention are as follows: By integrating the rotating coil that generates the rotating magnetic field and the traveling wave coil that generates the axial traveling wave magnetic field into the same core structure, it is possible to simultaneously apply rotating stirring force and axial electromagnetic thrust to the unsolidified molten steel in the continuously cast billet, thereby achieving the goal of comprehensively improving the flow state of the molten steel and the feeding effect. The radial arrangement of the two sets of coils can make full use of the space in the longitudinal direction to achieve compound stirring over a longer range, ensuring the stirring effect. This compound electromagnetic stirring effect can significantly reduce center segregation, center porosity, and shrinkage defects in the billet, ultimately improving the internal quality of continuously cast billets of high-alloy steel and other high-end steel grades. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of the structure of a composite electromagnetic stirrer for continuous casting of steel, as described in an embodiment of this utility model. Figure 2 This is an end view of the iron core and coil assembly described in this embodiment of the utility model; Figure 3 This is a schematic diagram of a single traveling wave coil structure according to an embodiment of the present invention; Figure 4This is a wiring diagram of the traveling wave coil embodiment one described in this utility model; Figure 5 This is a wiring diagram of Embodiment 1 of the rotating coil described in this utility model; Figure 6 This is an installation diagram of a composite electromagnetic stirrer for continuous casting of steel, as described in an embodiment of this utility model. In the diagram: 1. Outer shell; 2. Iron core; 3. Traveling wave coil; 4. Inlet and outlet water pipes; 5. Rotating coil; 6. Rear end plate; 7. Inner cylinder; 8. Continuous casting billet; 9. Bracket; 10. Front end plate; 11. Pressure ring; 12. Outlet box; 21. Iron core teeth. Detailed Implementation

[0017] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art are within the protection scope of the present utility model.

[0018] like Figure 1 As shown, this utility model discloses a composite electromagnetic stirrer for continuous casting of steel, including a non-magnetic outer shell 1 and an inner cylinder 7, with an iron core 2 disposed between the outer shell 1 and the inner cylinder 7. A set of rotating coils 5 are wound on the iron core 2, and a set of traveling wave coils 3 are embedded in the iron core 2. Pressure rings 11 for connection are provided at both ends of the iron core 2. A front end plate 10 and a rear end plate 6 are respectively installed at both ends of the outer shell 1 and the inner cylinder 7, which together form a sealed cavity to protect the internal coils. The continuously cast billet 8 passes through the inner cylinder 7, with a non-magnetic bracket 9 provided in between to maintain a certain distance between the continuously cast billet 8 and the inner cylinder 7.

[0019] The outer casing 1 is provided with a cable outlet box 12 for connecting the rotating coil 5 and the traveling wave coil 3 to an external power supply; at the same time, the outer casing 1 is provided with water inlet and outlet pipes 4 for connecting the cooling water of the coil and the casing.

[0020] During operation, supplying two-phase or three-phase alternating current to the rotating coil 5 generates a rotating magnetic field inside the agitator, applying a rotating electromagnetic force to the unsolidified molten steel in the continuously cast billet 8. Supplying two-phase or three-phase alternating current to the traveling wave coil 3 generates an axial traveling wave magnetic field, forming an electromagnetic thrust in the axial direction. If power is supplied to both sets of coils simultaneously, a spiral stirring force can be formed inside the billet, achieving a combined stirring effect on the molten steel.

[0021] In a specific embodiment of this application, such as Figure 2As shown, rotating coils 5 are arranged on the iron core 2. These rotating coils 5 are wound on the teeth 21 of the iron core, and their number is a multiple of 2 or 3; in this example, there are 6. Traveling wave coils 3 are solenoid structures, arranged axially, and embedded in the iron core 2; their number is also a multiple of 2 or 3.

[0022] In a specific embodiment of this application, such as Figure 3 As shown, it is a single traveling wave coil 3 made of sintered wire or hollow copper tube, and its structure is a solenoid coil.

[0023] Figure 4 and Figure 5 The diagrams show the wiring of traveling wave coil 3 and rotating coil 5, respectively. In this embodiment, both sets of coils use six coils connected in a three-phase star configuration, with each phase consisting of two coils connected in series.

[0024] Figure 6 This is a schematic diagram of the installation of the agitator of this utility model. The agitator is installed in the secondary cooling zone or at the end of solidification of the continuous casting machine, through which the continuous casting billet 8 passes. By adjusting the current, frequency, direction, and other parameters of the two sets of input coils, the magnitude, direction, and form of the stirring force can be controlled, thereby improving the flow state of the molten steel, enhancing the feeding effect, reducing defects such as center segregation, porosity, and shrinkage cavities, and meeting the production requirements of high-quality alloy steel continuous casting billets.

[0025] In summary, the device described in this application is installed in the secondary cooling zone or at the end of solidification of a continuous casting machine. It includes a non-magnetic outer shell and an inner cylinder, with an iron core positioned between the outer shell and the inner cylinder. A set of rotating coils is wound on the iron core, and a set of traveling wave coils is embedded within the iron core. The continuously cast billet passes through the inner cylinder. The two sets of coils are arranged radially, which can fully utilize the space in the longitudinal direction to achieve composite stirring over a longer range and ensure the stirring effect. A composite electromagnetic stirrer for continuous steel casting is powered by two independent, adjustable low-frequency power supplies to ensure adjustable electromagnetic force and spiral angle. A two-phase (or three-phase) alternating current is supplied to the rotating coil, generating a rotating magnetic field within the stirrer, thus producing a rotational force on the molten steel within the continuously cast billet. A two-phase (or three-phase) alternating current is supplied to the traveling wave coil, generating an axial traveling wave magnetic field within the stirrer, thus producing an axial up-and-down force on the molten steel within the continuously cast billet. Supplies of two-phase (or three-phase) alternating current to both the rotating and traveling wave coils simultaneously generate both rotating and traveling wave magnetic fields within the stirrer, thus producing a spiral stirring force on the molten steel within the continuously cast billet. The magnitude and direction of the stirring force can be adjusted and controlled via the power supply. The application of this invention can improve the flow of molten steel within the continuously cast billet, increase feeding force, reduce center segregation, alleviate center porosity and shrinkage cavities, and meet the quality requirements of high-alloy steel grades.

[0026] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A composite electromagnetic stirrer for continuous casting of steel, characterized in that, It includes a non-magnetic outer shell (1) and an inner cylinder (7), with an iron core (2) disposed between the outer shell (1) and the inner cylinder (7); a set of rotating coils (5) are wound on the iron core (2) for passing multiphase alternating current to generate a rotating magnetic field; a set of traveling wave coils (3) are embedded in the iron core (2) for passing multiphase alternating current to generate an axial traveling wave magnetic field; the continuous casting billet (8) passes through the inner cylinder (7), and the magnetic field generated by the rotating coils (5) and the traveling wave coils (3) can perform composite electromagnetic stirring on the unsolidified molten steel in the continuous casting billet (8).

2. The composite electromagnetic stirrer for continuous casting of steel according to claim 1, characterized in that, The rotating coil (5) is wound on the iron core tooth (21). The number of rotating coils (5) is a multiple of 2 or 3. The rotating coils (5) are connected in a star or delta configuration. After two-phase or three-phase alternating current is applied, a rotating magnetic field is generated.

3. The composite electromagnetic stirrer for continuous casting of steel according to claim 1, characterized in that, The traveling wave coil (3) is a solenoid winding. The number of traveling wave coils (3) is a multiple of 2 or 3. They are arranged along the axis. The traveling wave coils (3) are connected in a star or delta configuration. After two-phase or three-phase alternating current is applied, a traveling wave magnetic field along the axis is generated.

4. The composite electromagnetic stirrer for continuous casting of steel according to claim 1, characterized in that, The rotating coil (5) and traveling wave coil (3) are wound with hollow copper tubes or with sintered wire.

5. The composite electromagnetic stirrer for continuous casting of steel according to claim 1, characterized in that, The outer shell (1) and the inner cylinder (7) are respectively provided with a front end plate (10) and a rear end plate (6) at both ends, which together form a sealed cavity.

6. The composite electromagnetic stirrer for continuous casting of steel according to claim 1, characterized in that, A non-magnetic bracket (9) is provided between the continuous casting billet (8) and the inner cylinder (7), and there is a gap between the continuous casting billet (8) and the non-magnetic bracket (9).

7. The composite electromagnetic stirrer for continuous casting of steel according to claim 1, characterized in that, The outer casing (1) is provided with a cable outlet box (12) for connecting the rotating coil (5) and the traveling wave coil (3) to an external power supply.

8. The composite electromagnetic stirrer for continuous casting of steel according to claim 1, characterized in that, The outer casing (1) is provided with inlet and outlet water pipes (4) for connecting cooling water.

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