The present invention relates to a molding device for continuous casting, which is equipped with an agitator, of continuous casting equipment that produces a billet, a slab or the like made of non-ferrous metal of a conductor (conductive body), such as Al, Cu, Zn, or an alloy of at least two of them, or an Mg alloy, or other metal.
In the past, a melt agitating method to be described below has been employed in a casting mold for continuous casting. That is, for the improvement of the quality of a slab, a billet, or the like, in a process for solidifying the melt, that is, when the melt passes through the casting mold, a moving magnetic field, which is generated from the outside of the casting mold by an electromagnetic coil, is applied to the melt present in the casting mold so that agitation occurs in the melt not yet solidified. A main object of this agitation is to degas the melt and to uniformize the structure. However, since the electromagnetic coil is disposed at the position close to high-temperature melt, the cooling of the electromagnetic coil and troublesome maintenance are needed and large power consumption is obviously needed. In addition, the generation of heat from the electromagnetic coil itself caused by the power consumption cannot be avoided, and this heat should be removed. For this reason, there are various problems in that the device itself cannot but become expensive, and the like.
The invention has been made to solve the above-mentioned problems, and an object of the invention is to provide a molding device for continuous casting equipped with an agitator that reduces the amount of generated heat, is easy to carry out maintenance, is inexpensive, and is easy to use in practice.
A molding device for continuous casting equipped with an agitator according to an embodiment of the present invention is a device which receives liquid-phase melt of a conductive material and from which a solid-phase cast product is taken out through the cooling of the melt. The molding device includes a casting mold including a casting space that includes an inlet and an outlet at a central portion of a substantially cylindrical side wall and a magnetic field generation device receiving chamber that is formed in the side wall and is positioned outside the casting space, the casting mold receiving the liquid-phase melt from the inlet into the casting space and discharging the solid-phase cast product from the outlet through the cooling in the casting space, and an agitator provided so as to correspond to the casting mold, the agitator including a magnetic field generation device having an electrode unit that includes first and second electrodes supplying current to at least the liquid-phase melt present in the casting space, and a permanent magnet that applies a magnetic field to the liquid-phase melt. The magnetic field generation device is received in the magnetic field generation device receiving chamber of the casting mold, generates magnetic lines of force toward a center in a lateral direction, makes the magnetic lines of force pass through a part of the side wall of the casting mold and reach the casting space, and applies lateral magnetic lines of force, which cross the current, to the melt.
a) is a view illustrating the entire structure of an embodiment of the invention, and
a) is an explanatory plan view taken along line II(a)-II(a) of
a) is an explanatory plan view of a magnetic field generation device 31 of an agitator 3, and
a) is a plan view of another modified example of the magnetic field generation device 31 of the agitator 3, and
a) is a view illustrating the entire structure of yet another embodiment of the invention,
a) is a view illustrating the entire structure of still another embodiment of the invention,
For deeper understanding of an embodiment of the invention, an electromagnetic agitator, which uses electricity as power, of continuous casting equipment in the related art will be described briefly.
In the related art, a fixed amount of melt M of non-ferrous metal is discharged from a melt receiving box that is called a tundish and is poured into a casting mold that is provided on the lower side. Cooling water for cooling the casting mold is circulated in the casting mold. Accordingly, high-temperature melt starts to solidify from the outer periphery thereof (a portion thereof close to the casting mold) from the moment that the high-temperature melt comes into contact with the casting mold.
Since the melt, which is positioned at the central portion of the casting mold, is distant from the wall of the casting mold that is being cooled, the solidification of the melt positioned at the central portion of the casting mold is obviously later than that of the melt positioned at the peripheral portion of the casting mold. For this reason, two kinds of melt, that is, liquid (liquid-phase) melt and a solid (solid-phase) cast product are simultaneously present in the casting mold while being adjacent to each other with an interface interposed therebetween. Further, generally, if melt is solidified too rapidly, gas remains in the cast product (product) having been changed into a solid and causes the quality of the product to deteriorate. For this reason, degassing is facilitated by the agitating of the melt that is not yet solidified. The electromagnetic agitator, which uses electricity as power, has been used for the agitating in the related art.
However, when such an electromagnetic agitator is used, there are various difficulties as described above.
Accordingly, the invention is to provide a molding device for continuous casting equipped with an agitator that does not use the electromagnetic agitator using electricity as power and uses permanent magnets.
An embodiment of the invention will be described in more detail below.
The entire structure of an embodiment of the invention is illustrated in
As understood from
The melt supply unit 1 includes a tundish (melt receiving box) 1A that receives melt M from a ladle (not illustrated) or the like. The melt M is stored in the tundish (melt receiving box) 1A, inclusion is removed from the melt, and the melt M is supplied to the casting mold 2 from a lower opening 1B of the tundish at a constant supply rate. Only the tundish (melt receiving box) 1A is illustrated in
The casting mold 2 is adapted in this embodiment so that a columnar product P (billet) is taken out from the casting mold. For this purpose, the casting mold 2 is formed so as to have a substantially cylindrical double structure (of which the cross-section has a ring shape). That is, the casting mold 2 includes an inner casting mold 21 and an outer casting mold 22 that are fitted to each other. The inner casting mold 21 is provided on the inside and made of a non-conductive material (non-conductive refractory material) such as graphite (carbon). The outer casting mold 22 is provided on the outside and made of a conductive material (conductive refractory material), such as aluminum or copper.
As described in detail below, the magnetic field generation device 31 is assembled so as to be received within the side wall of the outer casting mold 22. Meanwhile, since the technical idea is the same as described above even when a prismatic product (slab) is taken out, the technical idea of an embodiment to be described below can be applied as it is. Briefly, the shapes of components corresponding to a rectangular slab, which is a product, are merely changed.
The casting mold 2 further includes a water jacket 23 outside the outer casting mold 22.
The water jacket 23 is to cool the melt M that flows into the inner casting mold 21. That is, cooling water flows into the water jacket 23 from an inlet (not illustrated) and is circulated in the water jacket 23, the outer portion of the outer casting mold 22 is cooled by the cooling water, and the cooling water is discharged from an outlet (not illustrated). The melt M is rapidly cooled by the water jacket 23. Since water jackets having various known structures may be employed as the water jacket 23, the detailed description thereof will not be provided here.
In addition, a plurality of electrode insertion holes 2a, 2a, . . . into which electrodes 32A to be described below are inserted are formed at a predetermined interval on the circumference of the casting mold 2 having the above-mentioned structure. The electrode insertion holes 2a are formed so as to be inclined downward toward the center of the casting mold 2. For this reason, if the surface of the melt M is lower than the upper openings of the electrode insertion holes 2a even though the melt M is contained in the casting mold 2, there is no concern that the melt M will leak to the outside.
As described above, briefly, the agitator 3 is provided so as to be built in the side wall of the casting mold 2. The agitator 3 includes a permanent magnet type magnetic field generation device 31, and a pair of upper and lower electrodes (positive and negative electrodes) 32A and 32B.
In particular, as understood from
As understood from the following description, the magnetic field generation device 31 does not necessarily need to be formed in the shape of a ring, and may be divided. That is, for example, as illustrated in
In more detail, as understood from
As described above, the four portions of the magnetic field generation device 31 are magnetized and form pairs of magnetic poles 31a, 31a, . . . as illustrated in
The magnetization may be contrary to this. That is, the inner portions of all magnetic poles may be magnetized to a certain pole and the outer portions thereof may be magnetized to an opposite pole. One of additional characteristics of the invention is that a plurality of magnetic poles are disposed at a plurality of positions surrounding the melt M, which is not yet solidified, as understood from
In
The respective electrodes 32A are inserted into the above-mentioned electrode insertion holes 2a. That is, the electrodes 32A penetrate into the casting mold 2 (the inner casting mold 21 and the outer casting mold 22) from the water jacket 23. Inner ends of the electrodes 32A are exposed to the inside of the inner casting mold 21, come into contact with the melt M, and conduct electricity to the melt M. Outer ends of the electrodes 32A are exposed to the outside of the water jacket 23. The outer ends are connected to a power supply 34 that can supply variable direct current. The power supply 34 may have the function of an AC power supply as described below, and may have a function of changing frequency. The electrodes 32A may be supported above the upper opening of the casting mold 2 without penetrating the side wall of the casting mold 2 so that the inner ends of the electrodes 32A are inserted into the melt M from the surface of the melt M flowing into the casting mold 2. The electrodes 32A may be electrically connected to the inner casting mold 21 made of graphite or the like.
The number of electrodes used as the electrodes 32A may be arbitrary, and an arbitrary number of the electrodes 32A may be inserted into arbitrary electrode insertion holes of the electrode insertion holes 2a, 2a, . . . .
In
Accordingly, when a voltage is applied between the pair of electrodes 32A and 32B from the power supply 34, current flows between the pair of electrodes 32A and 32B through the melt M and the product P. As described above, the power supply 34 is adapted so as to be capable of controlling the amount of current flowing between the pair of electrodes 32A and 32B. Therefore, it is possible to select current where the liquid-phase melt M can be agitated most efficiently in a relationship with the magnetic lines of force ML.
Next, the operation of the device having the above-mentioned structure will be described.
In
Further, since the permanent magnet type magnetic field generation device 31 is received in the side wall of the casting mold 2 as understood from
Now, cooling capacity is increased or reduced by the water jacket 23 or the like, the solidification rate of the melt M is changed and the interface IT0 between the melt (liquid-phase) M and a product (solid-phase) P moves up and down according to this. That is, when cooling capacity is increased, the interface IT0 moves up like an interface IT1 as illustrated in
On the contrary, the double structure of the casting mold 2 may be formed so that the inner portion of the casting mold is made of a conductive material and the outer portion thereof is made of a non-conductive material. In this case, at least the electrodes 32A may come into electronically contact with the conductive material that forms the inner portion of the casting mold. Even in this case, a magnetic field generation device receiving chamber 22a may be formed in an outer member.
Further, the casting mold 2 may have not a double structure but a single structure. In this case, the casting mold 2 may be made of only a conductive material, and the electrodes 32A may conduct electricity to the casting mold 2. The structure of the other electrode 32B may be the same as described above.
On the contrary, the casting mold 2 may be made of only a non-conductive material. In this case, it is necessary to make the electrodes 32A conduct electricity to the melt M present in the casting mold 2 by making the electrodes 32A penetrate into the casting mold 2 as illustrated in
In these cases, obviously, a magnetic field generation device receiving chamber 22a may be formed in a member having a single structure.
A magnetic field generation device 31A of
Further, magnetic field generation devices 31-2 and 31A-2 of
Furthermore, an electrode, which includes the roller 32Ba at the end thereof, has been described as the lower electrode 32B in the above-mentioned embodiment. However, the lower electrode does not need to necessarily include the roller 32Ba. Even though a product P is continuously extruded, the electrode 32B only has to conduct electricity to the product P and may employ various structures. For example, an elastic member having a predetermined length is used as the electrode 32B and is bent, for example, so as to be convex upward or downward in
According to the above-mentioned embodiment of the invention, it is possible to obtain the following effects.
In the embodiment of the invention, melt M that is not yet solidified is agitated to give movement, vibration, and the like to the melt M, so that a degassing effect and the uniformization and refinement of the structure are achieved.
In more detail, since the magnetic field generation device 31 is adapted so as to be capable of being adjusted in the vertical direction in the embodiment of the invention, it is possible to obtain a high-quality product P by reliably agitating the melt M. This is one of the characteristics of the invention as described above, and an idea, in which a magnetic field generation device 31 provided outside the casting mold is moved up and down in a device that is apt to be high temperature and large in size and hardly has an empty space as in the embodiment of the invention, itself is an idea that is not accustomed to those skilled in the art. Accordingly, a technique of the invention, in which a magnetic field generation device is received in a casting mold and can be adjusted in the vertical direction, is a technical idea that is peculiar to the inventor.
Further, since the magnetic field generation device 31 is formed in the embodiment of the invention so that a plurality of magnetic poles are disposed at the positions surrounding the melt M or a ring-shaped magnet surrounding the melt M is disposed, it is possible to efficiently agitate all the melt M with an electromagnetic force that is generated according to Fleming's rule by magnetic lines of force and current. Accordingly, it is possible to obtain a product P as a high-quality product. That is, in the embodiment of the invention, it is possible to efficiently agitate the melt M by making the best use of an electromagnetic force that is generated according to Fleming's rule. In addition, the axis of the rotation of the melt M, which is caused by this agitating of the melt, is an axis parallel to the center axis of the product P in
Moreover, in the embodiment of the invention, melt M is agitated with an electromagnetic force that is generated according to Fleming's rule and is agitated by the cooperation between small current flowing in the melt M and a magnetic field generated from the magnetic field generation device 31. Accordingly, it is possible to obtain a device that stably and continuously expects reliable agitation unlike melting and agitation performed using the intermittent flow of large current according to the principle of arc welding or the like and has low noise and high durability.
It is obvious that the above-mentioned effects are obtained from all embodiments to be described below.
Meanwhile, direct current has been supplied between the electrodes 32A and 32B in the above description, but alternate current having a low frequency of about 1 to 5 Hz may be supplied from the power supply 34. In this case, the melt M does not rotate but repeatedly vibrates according to the cycle thereof in the relationship with a magnetic field that is generated from the magnetic field generation device 31. Impurities are removed from the melt M even by the vibration. This modified example may be applied to all embodiments to be described below. In this case, it is obvious that a power supply having a function of changing frequency is employed as the power supply 34.
Further, the realization of mass production facilities is currently required in the industry. It is essential to realize a casting mold that is as small as possible when mass production is considered.
Here, the electromagnetic agitating device in the related art can cope with a case where several slabs or billets are produced at one time. However, at present, there is a demand for the production of billets of which the number exceeds 100. The electromagnetic agitator in the related art cannot cope with this demand.
However, permanent magnets are used as the magnetic field generation device in the device of the invention. For this reason, it is possible to make the device very compact in comparison with the electromagnetic agitator that is supplied with large current. Accordingly, it is possible to sufficiently realize a molding device for a mass production facility. Further, since the magnetic field generation device is permanent magnet type, it is possible to obtain a device having effects, such as no heat generation, power saving, energy saving, and less maintenance, as a magnetic field generation device.
More current is supplied to this liquid-phase melt M to generate a larger electromagnetic force so that the melt M is rotationally driven.
This embodiment is different from the embodiment of
That is, the casting mold 2A of this embodiment includes a substantially cylindrical casting mold body 2A1. The casting mold body 2A1 includes a circumferential groove 2A1(a) that is formed on the inner peripheral surface thereof. An insulating film 2A2 is formed on the inner surface (the peripheral surface and the bottoms) of this groove, and an embedded layer 2A3 is formed by embedding the same conductive material as the casting mold body 2A1 on the insulating film 2A2. An insulating layer portion is formed of the insulating film 2A2 and the embedded layer 2A3. The insulating layer portion is formed on a part of the inner surface of the casting mold, and functions as a portion that does not allow the flow of current from the casting mold.
This insulating layer portion is formed on a slightly lower portion of the inner surface of the casting mold body 2A1.
Accordingly, current is hardly allowed to flow to the cast product P from the insulating layer portion of the casting mold body 2A1, that is, a portion adjacent to the cast product P.
In addition, a terminal 2A4 is provided on the outer periphery of the casting mold body 2A1. Power can be supplied to the casting mold 2A from the power supply 34 through this terminal 2A4.
When a voltage is applied between the terminal 2A4 and the electrode 32B by the power supply 34 in the device having this structure, current flows in the casting mold body 2A1, the melt M, and the cast product P. Since current does not flow in the insulating film 2A2 and the embedded layer 2A3 at this time, larger current flows in the melt M. Accordingly, a larger electromagnetic force, which allows the melt M to be agitated, is obtained.
This embodiment is a modification of the embodiment of
This embodiment is different from the embodiment of
Other structures are the same as the embodiment of
This embodiment may be regarded as a modified example of the embodiment of
The embodiment of
In
Other structures are substantially the same as
a) to 8(d),
The same members of these embodiments as the members of the above-mentioned embodiment are denoted by the same reference numerals and the description thereof will not be repeated.
In these embodiments, a water jacket for cooling does not need to be separately provided, a water flow chamber 22a(2), which functions as both a cooling chamber and a magnetic field generation device receiving chamber, is formed in the side wall of a casting mold 2, that is, the side wall of the outer casting mold 22, and a magnetic field generation device 31 as a permanent magnet is received in the water flow chamber 22a(2) so that the position of the magnetic field generation device can be adjusted in the vertical direction.
Meanwhile, a magnetic field generation device receiving space (magnetic field generation device receiving chamber) 22a(2) illustrated in
First, a device of manufacturing a billet of the embodiment illustrated in
That is, as understood from
As understood from
The lower opening of the water flow chamber 22a(2) is closed by the above-mentioned ring-shaped lid 22B. A plan view of the lid 22B is illustrated in
Since the operation of the above-mentioned device of FIGS. 8(a) to 8(e) is the same as that of the above-mentioned embodiment, the description thereof will not be repeated.
Meanwhile, the magnetic field generation device 31 has been formed of the plurality of permanent magnet pieces 31A in the above-mentioned embodiment of
In the device of
That is, if the magnetic field generation device 31 is provided outside the casting mold, it is inevitable that a distance between the magnetic field generation device 31 and the melt M is slightly increased. However, since the magnetic field generation device is built in the casting mold 2 in this embodiment, the distance between the magnetic field generation device 31 and the melt M is reduced. Accordingly, a permanent magnet, which is small and has a small capacity, may be used to obtain the same agitating performance.
That is, when this device is operated, a plurality of inspectors should be positioned around the device to perform various kinds of measurement, nondestructive inspection, and the like and should perform such the measurement and the like for the check of a product P. However, in the case of the magnetic field generation device that is provided outside, the increase in size and volume cannot be avoided and it cannot be denied that it is difficult to perform such the measurement since a strong magnetic field is generated. However, since the magnetic field generation device 31 is provided in the casting mold 2 in this embodiment, a volume is not increased and the intensity of a magnetic field emitted to the outside is reduced. For this reason, it is easy to perform various kinds of measurement and the like.
That is, it is possible to reduce time required for the above-mentioned measurement and the like. As a result, it is possible to increase the manufacturing rate of a product P per unit time.
That is, since the magnetic field generation device 31 is a built-in type, it is possible to provide a device that is small as a whole as much as that.
That is, since the magnetic field generation device 31 is a built-in type when the device is regarded as a device manufacturing the same product P although being the same as described above, the size of the device is reduced as a whole. Accordingly, it is possible to install the device even at a narrow place. As a result, flexibility is obtained in the usefulness of the device.
The above-mentioned effects will be described below from a different standpoint.
When a product P is manufactured by this device, for example, five or six workers gather around the device and should perform high-density works (works for monitoring and preventing the leakage of melt, works for monitoring and preventing the jet of melt, and the like) in a short time. When these works are performed by a plurality of workers, a working property is good in the built-in type device of this embodiment as compared to a case where the magnetic field generation device 31 is provided outside so as to protrude. That is, since the external appearance of the device has the same dimensions as the dimensions of a device that does not include the magnetic field generation device 31 that is a device in the related art, the device of this embodiment is very easy to use at the work site.
Further, it is preferable that the magnetic field generation device 31 be close to the melt M as much as possible in order to reliably apply a magnetic field to the melt M, and this is realized in a built-in type.
When the magnetic field generation device 31 is provided outside, the influence of a magnetic field on various measuring instruments such as temperature sensors should be considered. However, since the influence thereof is reduced in a built-in type, a built-in type is more advantageous in measurement. That is, when a product P, such as a slab or a billet, is manufactured, the measurement, management, and the like of temperature in several positions are very important to maintain the quality of a product. This embodiment is very advantageous in the measurement of temperature and the like.
If a built-in type magnetic field generation device as in this embodiment is used instead of the magnetic field generation device provided outside, the size, weight, and volume of a device may be reduced when the same magnetic field is applied to the melt M. Accordingly, the device is easy to use. That is, since the respective components of this device are consumables, the respective components of this device need to be replaced whenever a predetermined operation time has passed. However, since the magnetic field generation device 31 is small and light, a work for replacing the magnetic field generation device and the like are very easily performed.
Since a work at the device of this embodiment is a work that is performed at a so-called high temperature of about 700° C., the work is very dangerous for a worker. However, a magnetic field generation device, which is small and of which the intensity of a magnetic field is low, may be used as the magnetic field generation device 31. Further, a tool, which is used for the adjustment, maintenance, and the like of the device, is generally a ferromagnetic body made of iron and safety shoes and the like are also made of iron. However, if a magnetic field of the magnetic field generation device 31, which is emitted by the outside, is reduced a little, the safety of a security officer, a worker, a measuring person, and the like is ensured.
It is obvious that the effects described above with reference to
a) to 9(c) illustrate a device for manufacturing a slab. However, the basic technical idea of the device is the same as described above except that a billet has a circular shape and a slab has a rectangular shape. Accordingly, the same members are denoted by the same reference numerals and the description thereof will not be repeated.
A difference will be described below.
The weight of a slab as a product P is very heavy. For this reason, a billet can be pulled in the horizontal direction, but a slab as a product P is not obtained unless taken out in the vertical direction. For this reason, a pedestal 51 is prepared, and a product P is taken out while riding the pedestal 51 and being gradually pulled downward. A lower electrode 32B is embedded in the pedestal 51. A magnetic field generation device 31 is illustrated in
In
Number | Date | Country | Kind |
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2011-246666 | Nov 2011 | JP | national |
This application is a continuation of U.S. patent application Ser. No. 14/115,788, filed Nov. 5, 2013, which is a 371 of International Patent Application No. PCT/JP2012/052412, filed Feb. 2, 2012, which claims priority to Japanese Patent Application No. 2011-246666, filed Nov. 10, 2011. The entire contents of U.S. patent application Ser. No. 14/115,788 are incorporated herein by reference.
Number | Date | Country | |
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Parent | 14115788 | Nov 2013 | US |
Child | 14825893 | US |