Melting vessel and electric arc furnace for electric arc furnace
By using magnetic steel for the vessel walls and a non-magnetic cover plate over a notch, the electric arc furnace achieves efficient magnetic stirring with cost-effective thermal expansion management.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- PRIMETALS TECH AUSTRIA GMBH
- Filing Date
- 2024-05-16
- Publication Date
- 2026-06-16
AI Technical Summary
Existing solutions for enabling magnetic flux passage in electric arc furnaces face challenges due to material expansion behavior differences and high costs, particularly when using non-magnetic materials for electromagnetic stirring devices.
The side walls and a partial region of the molten vessel are made of magnetic steel, with a non-magnetic cover plate over a notch, fastened to ensure expansion compatibility and minimize obstruction, using fasteners to maintain support and prevent sliding.
This configuration allows efficient magnetic stirring while accommodating thermal expansion differences, reducing costs and maintaining operational integrity.
Smart Images
Figure 2026519461000001_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of steel production, specifically, to the field of steel production using an electric arc furnace. The present invention relates to a melting vessel for an electric arc furnace having a closed side wall and a bottom of the melting vessel having a bottom surface.
Background Art
[0002] In the production of steel in an electric arc furnace, usually, steel bath movement is achieved using an Intergas porous plug installed in the melting vessel. A newer method of mixing the steel bath involves an electromagnetic stirring device installed below the lower vessel. Since the lower vessel is usually made of steel, it prevents the magnetic flux from passing from the stirring coil to the melt. One possible but very costly solution is to manufacture the melting vessel from a non-magnetic material. Another possible method is to weld a non-magnetic material to a partial region of the melting vessel. However, such materials usually have different material expansion behaviors in the temperature range that occurs in an electric arc furnace, so installation is not easy.
[0003] Patent Document 1 shows a configuration for fastening an electromagnetic stirrer to the side wall of a container for receiving a liquid material.
[0004] Patent Document 2 discloses a non-magnetic steel structure that enables a magnetic field to be directed from an electromagnetic stirrer or a brake towards the melt and can be arranged, for example, inside an electric arc furnace.
Prior Art Documents
Patent Documents
[0005]
Patent Document 1
Patent Document 2
Summary of the Invention
Problems to be Solved by the Invention
[0006] The objectives of the present invention are, firstly, to provide a cost-effective solution, and secondly, to enable different expansion behaviors for each of the materials used. [Means for solving the problem]
[0007] This objective is achieved by manufacturing the side walls and a first partial region of the bottom of the molten vessel, connected to the closed side walls, from a metal, preferably a steel having magnetic properties. The second partial region of the bottom of the molten vessel, surrounded by the first partial region, is configured as a notch. The size of the notch depends on the size of the electromagnetic stirring device. The size of the electromagnetic stirring device depends on the size of the molten vessel and the stirring effect to be achieved with respect to the molten material. The notch is closed by a cover plate having non-magnetic properties, the cover plate having an overlapping support surface, which is supported by the first partial region. The cover plate is mounted in a floating state, and fasteners positioned accordingly ensure that the cover plate always has an overlapping support surface around the entire circumference of the notch. The cover plate typically has a different expansion behavior than the metal from which the rest of the bottom of the molten vessel is manufactured. Therefore, the cover plate must be able to expand independently of the rest of the bottom of the molten vessel without additional stress resulting from the expansion behavior of the cover plate being introduced into the bottom of the molten vessel. The fasteners must be used to prevent the cover plate from sliding so that it no longer has an overlapping support surface. The fasteners can be welded plates that prevent further displacement in this direction when they reach the side of the notch. However, it is also conceivable that the cover plate is limited by the side walls so that it always has an overlapping support surface when sliding. The size of the notch depends on the size of the electromagnetic stirring device used. The notch has a projected surface area of at least 10% of the projected bottom area. In most cases, the bottom of the molten vessel is not a straight surface, and therefore the projected surface area is used. The size depends on the dimensions of the electromagnetic stirring device and the way in which the magnetic flux generated by the electromagnetic stirring device propagates.
[0008] In a preferred design, the notch has a size that at least corresponds to, or substantially corresponds to, the projected surface area of the proximal surface of the notch of an electromagnetic actuator, preferably an electromagnetic stirring device, which can be positioned below the molten vessel.
[0009] In a favorable design, the first sub-region has a width of at least 500 mm around its entire circumference.
[0010] In particularly preferred modifications, the fasteners are welded fasteners on the side walls of the molten vessel, on the cover plate, on the steps at the bottom of the molten vessel, and / or on the bottom of the vessel.
[0011] In a favorable design, the cover plate, made from one of the following materials, may consist of an austenitic stainless steel such as steel with material number 1.4828.
[0012] In an advantageous design, at the maximum displaceable position within the area of the tapping opening, the cover plate does not overlap with the tapping opening and preferably has a gap of at least 50 mm, and particularly preferably 100 mm. The precise design of the tapping opening depends on the shape of the notch. It is also conceivable that the cover plate has an elongated hole or notch in the shape of a circular segment.
[0013] In a preferred embodiment, the cover plate has a reinforcing plate on its underside, which protrudes through a notch. It is also conceivable to have at least three fasteners that simultaneously function as reinforcing plates.
[0014] In another preferred embodiment, the cover plate is arc-shaped, has the shape of a spherical segment, or is bent. These designs increase static strength and, as a result, can absorb larger loads than in the case of a planar bottom. An arc-shaped design is a configuration in which the cover plate has, for example, the shape of a circular arc. The exact shape of the arc depends on the shape of the bottom of the molten vessel. A bent design has at least one bent edge, which is bent so that its shape is adapted to the shape of the bottom of the molten vessel.
[0015] In another advantageous design, the molten vessel has a refractory lining on a cover plate at the bottom of the molten vessel and on a first partial region, and the side walls also have a refractory lining. When the molten vessel expands, the cover plate is pressed against the lining, thus allowing it to expand.
[0016] In a convenient embodiment, the first sub-region of the molten vessel bottom is manufactured in a single component or by a non-removable connection. The first sub-region is made of a single component or by a non-removable connection, such as a welded connection. However, of course, it is conceivable that additional components not required for the function of the molten vessel bottom may be fastened to the first sub-region of the molten vessel bottom by a removable connection.
[0017] In advantageous embodiments, the cover plate is manufactured in a single component or by non-removable connections. The cover plate is made of a single component or by non-removable connections, such as welded connections. However, it is certainly conceivable that additional components not required for the function of the cover plate may be fastened to the cover plate by removable connections.
[0018] In a preferred embodiment, the notch has a projected surface area of at least 20%, preferably at least 30%, particularly preferably at least 40%, and most preferably at least 50% of the projected base area.
[0019] In an advantageous embodiment, the cover plate is made of a non-magnetic metal, preferably non-magnetic steel.
[0020] This object is also achieved by an electric arc furnace comprising the above-mentioned melting vessel and an electromagnetic stirring device arranged below in a second partial region of the melting vessel.
[0021] The above-described properties, features, and advantages of the present invention, as well as the method for achieving them, will become clearer and more clearly understandable in connection with the following description of one exemplary embodiment. The embodiments will be described in more detail in connection with the drawings.
Brief Description of the Drawings
[0022] [Figure 1] It is a schematic view of an embodiment of a melting vessel. [Figure 2] It is a schematic view of an embodiment of a melting vessel. [Figure 3] It is a schematic view of an embodiment of a melting vessel. [Figure 4] It is a schematic view of an embodiment of a melting vessel. [Figure 5] It is a schematic view of an electric arc furnace having an embodiment of the melting vessel of the present invention. [Figure 6] It is a schematic view of an electric arc furnace having an embodiment of the melting vessel of the present invention. [Figure 7] It is a schematic view of an electric arc furnace having an embodiment of the melting vessel of the present invention. [Figure 8] It is a schematic view of an electric arc furnace having an embodiment of the melting vessel of the present invention.
Modes for Carrying Out the Invention
[0023] Figure 1 shows an embodiment of the melting vessel 1 according to the present invention. The melting vessel 1 consists of a closed side wall 3 and a melting vessel bottom 4, the melting vessel bottom 4 consisting of a first partial region 4b and a second partial region, the second partial region being a notch 5. The notch 5 is closed by a cover plate 10. This cover plate 10 has non-magnetic properties so that the electromagnetic stirring device located below it can operate as efficiently as possible, and the stirring effect can reach the molten material with minimal obstruction. The cover plate 10 has fasteners 11 so that the cover plate 10 slides on the fasteners 11 and always has a support surface around its entire circumference on the melting vessel bottom 4. In addition, the fasteners 11 should also be such that the cover plate 10 does not overlap with the tapping opening 2. The fasteners 11 can also be configured as reinforcing plates so that the cover plate 10 meets the necessary mechanical requirements. Figure 1 shows the width B of the bottom 4 of the molten vessel, which is at least 500 mm in order to have a sufficient support surface available for the cover plate 10.
[0024] Figure 2 shows a plan view of an embodiment of the melting vessel 1 according to the present invention. The melting vessel 1 also has a notch 5, which is closed using a cover plate 10. The melting vessel 1 has a closed side wall 3, which has a lining 6. At the displacement position of the cover plate 10a, the side wall 3 acts as a fastener, so that the overlap between the notch 5 and the cover plate 10 is always ensured.
[0025] Figures 3 and 4 show further embodiments of the melting vessel 1 according to the present invention. The cover plate 10 has a corresponding fastener 11 so that the cover plate 10 always overlaps with the notch 5 when the cover plate 10 slides. The overlapping support surface 4a can be seen very clearly in Figures 3 and 5. In Figure 4, the fastener 11 is attached to the bottom 4 of the melting vessel.
[0026] Figures 5 and 6 schematically illustrate an embodiment of an electric arc furnace having a molten vessel 1 and an electromagnetic stirring device 20. The electromagnetic stirring device 20 is positioned directly beneath a cover plate 10, which covers a notch 5. Figure 5 also shows a lining 6, which is present both on the bottom 4 of the molten vessel and on the side wall 3. The notch 5 has a size corresponding to the projected surface area of the proximal side 20a of the electromagnetic stirring device 20. Depending on the embodiment, the projected surface area of the distal side 20b of the electromagnetic stirring device 20 may be larger than the projected surface area of the notch 5.
[0027] Figures 7 and 8 each show an embodiment of an electric arc furnace having a molten vessel bottom 4, the molten vessel bottom 4 having a stepped shape in a first partial region 4b. A cover plate 10 is inserted into this stepped shape. This stepped shape can also function as a fastener. Furthermore, the cover plate 10 is either arc-shaped or has the shape of spherical segments.
[0028] While the present invention has been illustrated and described in more detail by preferred exemplary embodiments, the present invention is not limited to the disclosed embodiments, and those skilled in the art can derive other modifications from the disclosed embodiments without departing from the scope of protection of the present invention. [Explanation of Symbols]
[0029] 1. Melting vessel 2 Tapping openings 3 side wall 4. Bottom of the molten vessel 4a Support surface 4b First subregion 5 Notches 6 Lining 10, 10a Cover Plate 11 Fasteners 20 Electromagnetic stirring devices 20a Proximal side 20b Distal side B Width
Claims
1. A molten vessel (1) for an electric arc furnace having a closed side wall (3) and a molten vessel bottom (4) having a bottom surface, wherein the side wall (3) and a first partial region (4b) of the molten vessel bottom connected to the closed side wall (3) are made of metal, preferably steel having magnetic properties, and a second partial region of the molten vessel bottom (4) surrounded by the first partial region is configured as a notch (5), the notch (5) is closed by a cover plate (10), and the cover A melting vessel (1) characterized in that the plate (10) has non-magnetic properties, the cover plate (10) has an overlapping support surface, the overlapping support surface is supported by the first partial region, the cover plate (10) is mounted in a floating state, and a correspondingly positioned fastener (11) ensures that the cover plate (10) always has an overlapping support surface (4a) around the entire circumference of the notch (5), and the notch (5) has a projected surface area of at least 10% of the projected bottom area.
2. The melting vessel (1) according to claim 1, characterized in that the notch has at least a size corresponding to, or substantially corresponding to, the projected surface area having a proximal surface of an electromagnetic actuator, preferably an electromagnetic stirring device, which can be positioned below the melting vessel.
3. The melting vessel (1) according to claim 1 or 2, characterized in that the first partial region has at least a width (B) of at least 500 mm around its entire circumference.
4. The molten container (1) according to any one of claims 1 to 3, characterized in that the fasteners are the side wall of the molten container, a welded fastener (11) on the cover plate (10), a step in the bottom (4) of the molten container, and / or a fastener (11) welded to the bottom (4) of the molten container.
5. The molten vessel (1) according to any one of claims 1 to 4, characterized in that the cover plate is made of austenitic stainless steel.
6. A melting vessel (1) according to any one of claims 1 to 5, characterized in that the region of the tapping opening does not overlap with the tapping opening, preferably has a distance of at least 50 mm from the tapping opening, and particularly preferably has a distance of 100 mm.
7. The melting container (1) according to any one of claims 1 to 6, characterized in that the cover plate (10) has a reinforcing plate on its lower side, and the reinforcing plate protrudes through the notch (5).
8. The melting vessel (1) according to any one of claims 1 to 7, characterized in that the cover plate (10) is arc-shaped, has the shape of a spherical segment, or is bent.
9. The molten container (1) according to any one of claims 1 to 8, characterized in that the molten container (1) has a refractory lining in the first partial region of the cover plate (10) and the bottom portion (4) of the molten container, and the side wall (3) also has a refractory lining.
10. The molten vessel (1) according to any one of claims 1 to 9, characterized in that the first partial region (4b) of the bottom of the molten vessel is integrally molded or manufactured by a non-removable connector.
11. The molten vessel (1) according to any one of claims 1 to 10, characterized in that the cover plate (10) is integrally molded or manufactured by a non-removable connection part.
12. The melting vessel (1) according to any one of claims 1 to 11, characterized in that the notch (5) has a projected surface area of at least 20%, preferably at least 30%, particularly preferably at least 40%, and most preferably at least 50% of the projected bottom area.
13. The molten vessel (1) according to any one of claims 1 to 12, characterized in that the cover plate (10) is made from a non-magnetic metal, preferably non-magnetic steel.
14. An electric arc furnace comprising a melting vessel according to any one of claims 1 to 13, and an electromagnetic stirring device (20) disposed on the lower side of the second partial region of the melting vessel (1).