JP3607887B2 - Continuous casting mold - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a continuous casting apparatus having an electromagnetic coil, and relates to a mold that can stably apply an electromagnetic force to molten metal in a mold and obtain a high-quality slab over a long period of time.
[0002]
[Prior art]
In the continuous casting technology of molten metal, a technology that uses electromagnetic force during casting has been developed in order to stabilize the molten metal surface, smooth the surface of continuously cast slabs, and increase the casting speed. In Japanese Patent Laid-Open No. 52-32824, as shown in FIG. 12, an alternating current is supplied to a current-carrying coil 35 arranged so as to surround a mold 31 and insulated by a refractory, It is disclosed that the surface properties can be improved by curving the meniscus portion 32 and encouraging the inflow of the powder 34 and reducing the contact pressure between the mold and the slab during initial solidification. However, an alternating current magnetic field applied by the electromagnetic coil induces an induced current in the cooling copper plate constituting the mold, and the surface effect attenuates the magnetic field to be applied to the molten metal in the mold.
[0003]
In order to suppress the attenuation of the magnetic field in the mold in this technique using the electromagnetic force and further improve the electromagnetic effect, Japanese Patent Laid-Open No. 05-15949 discloses a metal product having an internal water cooling structure as shown in FIG. A metal continuous casting apparatus including a mold 31 and an electromagnetic coil 35 that circulates around the mold and allows high-frequency current to pass therethrough. The mold 31 a) extends in the casting direction to the upper part thereof and reaches the upper end of the mold. A segment portion 37 having an internally coolable structure divided by a plurality of slits 36 not reaching, or b) an internally coolable segment divided by a plurality of slits 36 extending in the casting direction and reaching the upper end of the mold A continuous casting apparatus having a 37 portion and a plurality of girders connecting the segment portions, and the electromagnetic coil 35 is arranged so as to go around the segment portion, It is shown.
[0004]
However, a mold provided with such a slit cannot be reinforced with a back plate or the like and has low rigidity, so that the mold is likely to be thermally deformed and can be applied to a mold for casting a large cross section such as a slab. It was difficult. In order to solve these points, in Japanese Patent Laid-Open No. 2000-246397, as shown in FIG. 10, the metal in the vicinity of the meniscus initial solidification portion of the molten metal in the continuous casting mold is electromagnetically directed in the direction perpendicular to the mold wall. In the molten metal continuous casting apparatus to which a force is applied, an electromagnetic coil 35 for applying an alternating current to the outer peripheral surface of the mold 31, a pair of first cooling copper plates 39, and a nonmagnetic stainless steel combined with the copper plates And a pair of second cooling copper plates 40, a second back plate 42 made of nonmagnetic stainless steel combined with the copper plates, and a plurality of divided coolings including an insulator 46. Each of the first cooling copper plate and the second cooling copper plate has at least one groove on a surface opposite to the casting surface, and each of the first and second cooling copper plates By sealing and fixing the surface side having the groove of the first and second cooling copper plates with a back plate combined with the cooling copper plate of 2, the groove forms a cooling passage 43, and the first cooling copper plate and The second cooling copper plate is electrically insulated through an insulator 46, and the first back plate and the second back plate are fastened in an electrically insulated state. And a casting mold.
[0005]
[Problems to be solved by the invention]
In the mold of the continuous casting apparatus disclosed in the above Japanese Patent Laid-Open No. 2000-246397, the loss of electromagnetic force can be reduced, and the processing accuracy and assembly accuracy can be ensured by dividing the entire length of each side of the mold as a unit. There is an advantage.
[0006]
In the above publication, electrical insulation is achieved by interposing an insulator between the first back plate 41 and the second back plate 42 and fastening, or by providing a gap 50 without interposing an insulating material. Is disclosed.
[0007]
However, as a result of the water-cooled copper plate being worn or deformed by repeated use of the mold, the first and second cooling copper plates 39 and 40 are supported and fixed by the first and second back plates 41 and 42 to form the mold. When doing so, the interval between the back plates changes. For this reason, even if an insulator is inserted, a gap is always generated. The operation of adjusting the thickness of the insulating material sandwiched in order to insulate the back plates from each other is necessary and is not efficient. In addition, when trying to ensure electrical insulation by the gap, molten metal splash, dust, water, and water vapor enter and adhere to the gap during casting, resulting in a decrease in insulation between the back plates and induced current. There exists a problem that it becomes easy to flow and the electromagnetic force which should be given to molten metal falls. In addition, even if insulation is provided only on the mating surfaces of the back plates, as shown in FIG. 9, the insulating part may be exceeded, and splash and dust may adhere across the back plates, causing a short circuit. However, there is a problem that it is difficult to obtain stable insulation.
[0008]
The present invention is a continuous casting apparatus having an electromagnetic coil, which can ensure the insulation of the mold and stably apply the electromagnetic force even when the mold is used for a long period of time. The present invention provides a continuous casting mold capable of obtaining a piece.
[0009]
[Means for Solving the Problems]
In order to solve the above problems, the present invention has the following structure.
[0010]
(1) It has an electromagnetic coil, a pair of first cooling copper plates is sandwiched between a pair of second cooling copper plates, and the mating surface of the first cooling copper plate and the second cooling copper plate is: A pair of first back plates combined with the first cooling copper plate and a pair of second back plates combined with the second cooling copper plate, which are electrically insulated from each other through an insulator; Is a continuous casting mold of a continuous casting apparatus that is electrically insulated and fastened and fixed through an insulator ,
Among pre Symbol first cooling first copper plate with a pair of combined back plate and the second pair second backplate in combination with the cooling copper plate, insulated with a gap of at least one of the back plate surface A continuous casting mold characterized in that a range over the entire height in the vertical height direction of the outer peripheral surface including is coated with an electrical insulator.
[0011]
(2) It has an electromagnetic coil, a pair of first cooling copper plates are sandwiched between a pair of second cooling copper plates, and the mating surface of the first cooling copper plate and the second cooling copper plate is: A pair of first back plates combined with the first cooling copper plate and a pair of second back plates combined with the second cooling copper plate, which are electrically insulated from each other through an insulator; Is a continuous casting mold of a continuous casting apparatus that is electrically insulated and fastened and fixed through an insulator ,
Among pre Symbol first cooling first copper plate with a pair of combined back plate and the second pair second backplate in combination with the cooling copper plates, combined with the cooling copper plates of the at least one back plate A continuous casting mold characterized in that a range over the entire height in the vertical height direction of an outer peripheral surface including a surface insulated by a gap excluding the surface is covered with an electrical insulator.
[0012]
(3) It has an electromagnetic coil, a pair of first cooling copper plates are sandwiched between a pair of second cooling copper plates, and the mating surface of the first cooling copper plate and the second cooling copper plate is: A pair of first back plates combined with the first cooling copper plate and a pair of second back plates combined with the second cooling copper plate, which are electrically insulated from each other through an insulator; Is a continuous casting mold of a continuous casting apparatus that is electrically insulated and fastened and fixed through an insulator ,
Among pre Symbol first cooling first copper plate with a pair of combined back plate and the second pair second backplate in combination with the cooling copper plates, combined with the cooling copper plates of the at least one back plate A range covering the entire height in the vertical height direction of the outer peripheral surface including the surface that is insulated by the gap excluding the surface and the surface opposite to the combined surface is covered with an electrical insulator. Continuous casting mold.
[0013]
(4) The continuous casting mold according to any one of (1) to (3), wherein the electrical insulator covering the back plate is Teflon (registered trademark) or ceramics.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the drawings of embodiments.
[0015]
FIG. 1 is a perspective view showing an assembly concept of a continuous casting mold of the present invention, and FIGS. 2 to 6 are schematic horizontal sectional views of the continuous casting mold of the present invention assembled in this way. . 1 to 6, the continuous casting mold of the present invention is a pair of opposing first cooling copper plates 1 and 1 (usually the short side of the mold) and a pair of opposing first cooling copper plates 1 and 1. 2 cooling copper plates 2 and 2 (usually the long side of the mold) and the mold wall surface, and further, on the back side of these cooling copper plates, that is, the surface of the cooling copper plate opposite to the side in contact with the molten steel, A pair of first back plates 5, 5 that combine and support the first cooling copper plates 1, 1, and a pair of second back plates that combine and support the second cooling copper plates 2, 2. Back plates 6 and 6 are provided. Further, the mating surface 12 between the first cooling copper plate 1, 1 and the second water-cooled copper plate 2, 2 disposed therebetween is electrically insulated by an insulator and the first back plate 5. , 5 and the second back plates 6, 6 combined therewith are electrically insulated and fastened.
[0016]
The back plate is preferably made of nonmagnetic stainless steel, and there is a gap 13 between the first back plates 5, 5 and the second back plates 6, 6. Are insulated and fastened. That is, an insulating washer 10 and an insulating sleeve 11 are interposed between the head and shaft portion of the fastening bolt 9 and the outer peripheral surface of the back plates 6 and 6 and the inner surface of the bolt hole. And fastened and fixed, thereby forming a mold.
[0017]
A coil 8 for supplying an alternating current for applying an alternating magnetic field to the molten metal in the mold at the time of casting is provided on the outer periphery of the mold thus configured. In the present invention, an insulator refers to an electrical insulator.
[0018]
In the continuous casting mold of the present invention, in order to further ensure the electrical insulation of the back plate, a pair of first cooling copper plates 1 and 1 combined with the first cooling copper plates 1 and 1 as shown in FIG. The outer peripheral surface of at least one of the pair of second back plates 6, 6 combined with one back plate 5, 5 and the second cooling copper plate 2, 2 is covered with an electrical insulator 7. To do.
[0019]
Further, in the continuous casting mold of the present invention, as shown in FIG. 3, a pair of first back plates 5, 5 combined with the first cooling copper plates 1, 1 and second cooling copper plates 2, 2 are combined. The outer peripheral surface of the pair of second back plates 6 and 6 which is combined with the cooling copper plate of at least one of the back plates, that is, the outer peripheral surface except the surface 14 in contact with the cooling copper plate is covered with the electrical insulator 7 To do.
[0020]
That is, the back plate 5 and the cooling copper plate 1 are in close contact with each other, and since there is almost no gap between the cooling copper plate 1 and the surface 14 of the back plate that contacts the cooling copper plate, splash and dust may enter. Even if the insulating coating is not formed on this surface, there is little possibility that the insulating property is lowered. Therefore, only the outer peripheral surface excluding the surface 14 combined with the cooling copper plate of the back plate, that is, the outer peripheral surface contacting the cooling copper plate, in other words, the outer peripheral surface not combined with the cooling copper plate, that is, not contacting the cooling copper plate. Only the insulating coating is formed.
[0021]
Further, in the continuous casting mold of the present invention, as shown in FIG. 4, it is combined with a pair of first back plates 5, 5 and second cooling copper plates 2, 2 combined with the first cooling copper plates 1, 1. The outer peripheral surface excluding the surface 14 combined with the cooling copper plate of at least one of the pair of second back plates 6 and 6 and the surface 15 opposite to the combined surface is electrically insulated. It coats with.
[0022]
That is, in addition to the surface 14 combined with the cooling copper plate described in FIG. 3, the surface 15 opposite to the combined surface 14 does not have a surface of the back plate that forms a gap opposite to this surface, Since splash, dust, etc. are less likely to adhere to the surface, there is little possibility of a decrease in insulation even if an insulating coating is not formed on this surface. For this reason, an electrically insulating coating is formed on the outer peripheral surface of the back plate except for the surface 14 combined with the cooling copper plate and the surface 15 opposite to the combined surface. As a result, the area for forming the electrical insulation coating can be reduced, which is advantageous in terms of cost.
[0023]
In the examples of FIGS. 2, 3, and 4, the first back plates 5 and 5 combined with the first cooling copper plate are provided with insulating coatings, but as shown in FIG. Only the back plate may be used. Moreover, as shown in FIG. 6, you may provide an insulating coating similarly to the 2nd backplates 6 and 6 combined with a 2nd cooling copper plate. Note that the area to be covered with insulation is preferable in terms of cost because the first back plate combined with the first cooling copper plate (usually the short side) is relatively small.
[0024]
As the insulating coating formed on the back plate, an electrically insulating material having heat resistance, Teflon (registered trademark), ceramics, or the like can be used. In particular, Teflon (registered trademark) is preferable because of its excellent workability. In addition, although the cost is high, an insulating coating sprayed with ceramics such as alumina and zirconia is preferable because it further improves both heat resistance and wear resistance.
[0025]
As described above, the insulating coating on these back plates can be formed by applying and baking an insulating material or spraying the base material (back plate) after blasting. Particulate Teflon (registered trademark) may be disposed so as to cover the processed surface, and may be heated and welded. The thickness of the insulating coating is preferably about 0.5 to 1 mm. This insulating film is preferably formed over the entire height in the vertical height direction of the back plate in order to prevent the insulation from being lowered as much as possible by adhesion of splash and dust.
[0026]
As described above, the mating surface 12 of the first cooling copper plate 1 and the second cooling copper plate 2 disposed across the first cooling copper plate 1 is provided with an insulator and is electrically insulated. These insulators are arranged on one or both surfaces of the cooling copper plate 1 and the cooling copper plate 2. That is, FIG. 7 is a schematic horizontal sectional view in which the vicinity of the corner portion of the continuous casting mold of the present invention shown in FIGS. In the example shown in FIGS. 2 to 6, as shown in FIG. 7A, both the first cooling copper plate 1 and the mating surface 12 of the second cooling copper plate 2 disposed so as to sandwich the first cooling copper plate 1. Insulators 3 and 4 are provided. As shown in FIGS. 7 (b) and 7 (c), the insulator of this mating surface is either one of the cooling copper plate 1 and the cooling copper plate 2. It may be arranged on the surface.
[0027]
The insulator provided on the mating surfaces may be an electrically insulating material having heat resistance, but is preferably an electrically insulating ceramic having excellent wear resistance. As such ceramics, alumina ceramics, zirconia ceramics, and the like can be applied. In order to provide an insulator on the mating surface of the cooled copper plate, an insulator, for example, an alumina plate, is bonded to the surface of the copper plate by a method such as bonding with a heat-resistant adhesive, or a powder of the insulator is plasma or gas sprayed. For example, a method of forming them can be employed as appropriate.
[0028]
In the mold of the present invention, the cooling copper plate may be cooled by providing a water cooling passage between the copper plate and the back plate as disclosed in Japanese Patent Application Laid-Open No. 2000-246397, or through holes in the copper plate. It is possible to adopt a known method such as piercing and providing a cooling water channel.
[0029]
【Example】
A water-cooled mold with an internal dimension of 1500 mm x 250 mm and a height of 800 mm is composed of a 20 mm thick copper plate, and a 50 mm thick non-magnetic stainless steel back plate is placed on the back to form the mold. Then, an electromagnetic coil was installed on the outer periphery of this mold to obtain a mold having a horizontal sectional structure as shown in FIG. An insulating washer 10 and an insulating sleeve 11 are provided on a contact surface between the outer surface of the second back plate 6 and the inner surface of the bolt hole and the head and the shaft portion of the fastening bolt 9, and on the outer peripheral surface of the first back plate 5, Teflon (registered trademark) was coated with a thickness of 1 mm to form an insulating coating 7. However, as shown in FIG. 7B, zirconia-based ceramics is sprayed on the first cooling copper plate 1 on the mating surface of the first cooling copper plate 1 and the second cooling copper plate 2 to obtain a thickness of 0. An insulator 3 having a mating surface of 5 mm × width 20 mm × height 800 mm was formed.
[0030]
Using the mold of the present invention configured as described above, molten steel of S45C as a molten metal was supplied to the mold, and continuous casting was performed while an alternating current of 100 Hz was applied to the electromagnetic coil 8. As a comparative example, casting was similarly performed using a mold in which an insulating coating was not formed on the outer peripheral surface of the back plate.
[0031]
After casting, the coil is energized and the magnetic field strength at the center of the coil in the vertical direction and at the center of the mold width and thickness is measured. The magnetic field strength at each time point and the magnetic field strength at the initial state are measured. The ratio, ie the relative magnetic field strength, was investigated. The result is shown in FIG.
[0032]
As can be seen from FIG. 8, when the conventional mold is used, the relative magnetic field strength decreases with the lapse of the casting time, whereas when the mold of the present invention is used, the casting time is 100 hours. It can be seen that there is no decrease in the relative magnetic field even when exceeding, and that insulation is sufficiently ensured as in the initial stage.
[0033]
【The invention's effect】
Since the continuous casting mold of the present invention has an insulating coating formed on the back plate, it is possible to efficiently and reliably prevent a decrease in electrical insulation between the back plates constituting the mold due to splash and dust adhesion. When continuously casting molten metal by applying electromagnetic force, the insulation of the mold can be ensured for a long period of time, the electromagnetic force can be stably applied, and the mold can be maintained and managed efficiently. Can be obtained.
[Brief description of the drawings]
FIG. 1 is an assembly conceptual diagram of a continuous casting mold of the present invention.
FIG. 2 is a schematic horizontal sectional view of a continuous casting mold according to the present invention.
FIG. 3 is a schematic horizontal sectional view of another continuous casting mold of the present invention.
FIG. 4 is a schematic horizontal sectional view of another continuous casting mold of the present invention.
FIG. 5 is a schematic horizontal sectional view of another continuous casting mold of the present invention.
FIG. 6 is a schematic horizontal sectional view of another continuous casting mold of the present invention.
FIG. 7 is a partial horizontal cross-sectional schematic view showing the arrangement of insulators on the mating surface of the cooling copper plate of the continuous casting mold of the present invention, wherein (a) shows both sides of the mating surface, and (b) shows (C) shows the situation where an insulator is disposed on one surface of the mating surface and the other surface of the mating surface, respectively.
FIG. 8 is a diagram showing the relationship between casting time and relative magnetic field strength in the continuous casting mold of the present invention.
FIG. 9 is a partial horizontal cross-sectional schematic view showing the state of adhesion of deposits to the back plate of a conventional continuous casting mold.
FIG. 10 is a horizontal sectional view of a conventional continuous casting mold.
FIG. 11 is a horizontal sectional view of a conventional continuous casting mold.
FIG. 12 is a conceptual diagram showing a continuous casting technique for applying electromagnetic force.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... 1st cooling copper plate 2 ... 2nd cooling copper plate 3 ... Insulator 4 of the mating surface of the 1st cooling copper plate ... Insulator 5 of the mating surface of the 2nd cooling copper plate ... 1st back plate 6 ... 1st 2. Back plate 7 ... Electrical insulation coating 8 ... Electromagnetic coil 9 ... Fastening bolt 10 ... Insulation washer 11 ... Insulation sleeve 12 ... Cooling copper plate mating surface 13 ... Gap 14 ... Back plate combination surface 15 with cooling copper plate ... Back Side opposite to the combined surface 31 of the plate with the cooling copper plate 31 ... mold 32 ... molten metal 33 ... meniscus 34 ... powder 35 ... electric coil 36 ... slit 37 ... segment 38 ... immersion nozzle 39 ... first cooling copper plate 40 ... second Cooling copper plate 41 ... first back plate 42 ... second back plate 43 ... cooling water passage 44 ... fastening bolt 45 ... fastening bolt 46 ... insulator 47 ... seal thing 48 ... To surface 49 ... casting surface 50 ... gap

Claims (4)

An electromagnetic coil is provided, and a pair of first cooling copper plates are sandwiched between a pair of second cooling copper plates, and a mating surface between the first cooling copper plate and the second cooling copper plate is made of an insulator. A pair of first back plates combined with the first cooling copper plate and a pair of second back plates combined with the second cooling copper plate are insulated from each other. In a continuous casting mold of a continuous casting apparatus which is electrically insulated and fastened and fixed through an object ,
Among pre Symbol first cooling first copper plate with a pair of combined back plate and the second pair second backplate in combination with the cooling copper plate, insulated with a gap of at least one of the back plate surface A continuous casting mold characterized in that a range over the entire height in the vertical height direction of the outer peripheral surface including is coated with an electrical insulator. An electromagnetic coil is provided, and a pair of first cooling copper plates are sandwiched between a pair of second cooling copper plates, and a mating surface between the first cooling copper plate and the second cooling copper plate is made of an insulator. A pair of first back plates combined with the first cooling copper plate and a pair of second back plates combined with the second cooling copper plate are insulated from each other. In a continuous casting mold of a continuous casting apparatus that is electrically insulated and fastened through an object ,
Among pre Symbol first cooling first copper plate with a pair of combined back plate and the second pair second backplate in combination with the cooling copper plates, combined with the cooling copper plates of the at least one back plate A continuous casting mold characterized in that a range over the entire height in the vertical height direction of an outer peripheral surface including a surface insulated by a gap excluding the surface is covered with an electrical insulator. An electromagnetic coil is provided, and a pair of first cooling copper plates are sandwiched between a pair of second cooling copper plates, and a mating surface between the first cooling copper plate and the second cooling copper plate is made of an insulator. A pair of first back plates combined with the first cooling copper plate and a pair of second back plates combined with the second cooling copper plate are insulated from each other. In a continuous casting mold of a continuous casting apparatus that is electrically insulated and fastened through an object ,
Among pre Symbol first cooling first copper plate with a pair of combined back plate and the second pair second backplate in combination with the cooling copper plates, combined with the cooling copper plates of the at least one back plate A range covering the entire height in the vertical height direction of the outer peripheral surface including the surface that is insulated by the gap excluding the surface and the surface opposite to the combined surface is covered with an electrical insulator. Continuous casting mold. The mold for continuous casting according to any one of claims 1 to 3, wherein the electrical insulator covering the back plate is Teflon (registered trademark) or ceramics.

Images