JPH0227062B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a gas-blown mold with a built-in electromagnetic stirring device in continuous casting equipment.

(Prior art) In recent years, continuous casting equipment for high-grade steels has been equipped with a mold that incorporates an electromagnetic stirring device that imparts fluid motion to the molten steel in the mold to improve the equiaxed crystallinity and lift inclusions. provided.

This electromagnetic stirring device applies the principle of an induction motor, and an electromagnetic coil that generates a rotating magnetic field is placed around the outer periphery of the mold, and the rotating magnetic field gives fluid motion to the molten steel in the mold. It's getting old.

On the other hand, continuous casting equipment has also been put into practical use, in which flux is introduced into the mold together with molten steel, and flux is interposed between the two to prevent seizure of the molten steel while continuously drawing the molten steel below the mold.

However, although the electromagnetic stirring device improves the internal quality of the slab, the improvement in surface quality is insufficient. Therefore, it has been found that increasing the stirring speed of molten steel by electromagnetic stirring will improve the surface quality, but there is a problem that the speed cannot be increased due to the entrainment of flux.

(Object of the Invention) The present invention utilizes a mold equipped with an electromagnetic stirring device that can improve the internal quality of the mold, and rationally incorporates an inert gas blowing device that can improve the surface quality of the mold. The basic objective is to simultaneously improve the internal and surface quality of the piece.

(Structure of the Invention) Therefore, in the present invention, a rectangular cylindrical mold wall is constructed with four flat inner plates, each inner plate is formed with a porous plate on the inside, and the outer side of the porous plate is A shielding plate made of a heat transfer material is provided to integrally connect the two plates, and a gap is provided between the two plates to introduce an inert gas. The side parts of each inner plate are butted against each other while being supported by plates, the side parts of each back up plate are fastened together, and the mutually fastened back up plates are sandwiched between a pair of sandwiching frames from both sides. and the pinching frames are fastened to each other, and further, a backup plate configured by connecting both sides of each pinching frame to each of a pair of hanger frames, and the pair of pinching frames and the hanger frame are mutually fastened. In addition to storing the electromagnetic coil between
The electromagnetic coil is supported by a part of the outer periphery of the backup plate.

Then, an electromagnetic stirring device attached to the mold gives fluid motion to the molten steel, while an inert gas is blown into the mold from a porous plate to eliminate sliding friction and continuously cast the molten steel without flux or vibration. It is.

(Effects of the Invention) According to the present invention, the internal quality of the slab can be improved by the electromagnetic stirring device provided to the mold, and at the same time, the surface quality of the slab can also be improved by the gas blown from the porous plate. Can be done.

In addition, a vibration device for the mold is not required, and since the mold does not vibrate, it is possible to prevent poor lubrication and disturbance of oscillation marks on the surface of the slab due to shaking of the melt surface during electromagnetic stirring.

Furthermore, the gas-blown mold with a built-in electromagnetic stirring device has a structure in which the mold wall, back-up plate, etc. are not integrated and can be disassembled, and the back-up plate is held between sandwich frames. Since the electromagnetic coil is interposed between the clamping frame and the hanger frame that supports the clamping frame, assembly is very simple and the assembly can be made relatively compact.

Furthermore, the inner plate is formed of a porous plate with a porous layer, and a shielding plate made of a good heat transfer material is provided on the outside of the porous plate to integrally connect the two plates, and between the two plates. Since a gap is provided for introducing gas, a mold with a simple structure, easy to manufacture and assemble, and with little damage and high durability can be obtained.

(Embodiment) As shown in FIG. 1, a mold 1 consists of four flat thin inner plates 1a, 1a', 1b, and 1b' made of non-magnetic material. In this embodiment, one set of inner plates 1a, 1a' are wide inner plates, while the other set of inner plates 1b, 1b' are small width inner plates. And the inner width plate 1b, 1
b' are arranged on both sides so that the side end surfaces 1d of the other pair of wide inner plates 1a, 1a' abut against the end surface 1e of the protrusion 1c forming the rounded corner of the square cylindrical wall. ing.

The inner plates 1a, 1a', 1b, and 1b' are each formed of a porous plate 17 having a porous layer on the inside, and an interference plate 18 made of a good heat transfer material is provided on the outside of the porous plate 17. 17 and 18 are integrally constructed by sintering, brazing, or mechanically fastening.

A gap 19 for introducing an inert gas is provided between the two plates 17 and 18, and the inert gas introduced from the backup plate side, which will be described later, is evenly distributed and passed through the pores of the porous plate 17 to the inner surface of the mold. It will blow out evenly.

The porous plate 17 is made of metal powder such as Cu, Ni, Cu-Ni, etc. or Al ₂ O ₃ , Si ₃ O ₄ , BN in the metal powder.
It is preferable to form a mixture of porcelain powders such as porcelain powder into a plate shape and sinter it, and the porous plate 17 is
It has countless minute ventilation holes that communicate between the front and back sides. The shielding plate 18 is made of Cu, Ni, Cu-Ni.
It is preferable to use a metal plate such as .

The above-mentioned inert gas is blown into the mold from the porous plate 17 through a large number of ventilation holes, and forms a gas layer between the molten steel introduced into the mold and the inner surface of the mold to insulate the molten steel, thereby preventing the molten steel from baking the mold. will be prevented. Then, the sliding friction between the mold and the molten steel is made zero, and continuous casting can be performed without vibrating the mold.

Each of the inner plates 1a, 1a', 1b, 1b' is a back-up plate 2a, 2a', 2 made of non-magnetic material.
It is designed to be supported by b and 2b'. That is, as shown in FIGS. 2 to 5, each back-up plate has a plurality of bolt holes 3a, and each inner plate has stud bolts 3 fixed to the entire back surface at positions corresponding to the bolt holes 3a. Each stud bolt 3 is inserted into each bolt hole 3a and then tightened with a nut. Of course, in this case, the diameter of the bolt hole 3a is such that the stud bolt 3 can move during thermal expansion of the inner plate.

Each of the backup plates is provided with a plurality of water holes S16 and S9 in the upper and lower portions thereof penetrating in the thickness direction, and the upper water hole S16 and the lower water hole S9 are provided on the surface facing each inner plate. It has upper and lower water passage holes S10 that communicate with each other.

The 3rd to 5th sides of each backup plate are
As shown in the figure, the convex part 2c on one side of the adjacent inner plate is fitted into the concave part 2d on the other side (clasp connection). As clearly shown, a bolt 5 is inserted into a hole 5a provided on the side of the convex portion 2c and screwed into the concave portion 2d. A counter spring 6 is interposed on the bolt 5 so that each backup plate can move slightly in each orthogonal direction. In addition,
Like the bolt hole 3a, the hole 5a is made slightly larger in diameter than the bolt 5 so that adjacent backup plates can move slightly in the orthogonal direction to each other.

Backup plates 2a, 2a', 2b, 2
By assembling b' as described above, the end surfaces 1d of both sides of the pair of wide inner plates 1a, 1a' are brought into pressure contact with the end surfaces 1e of the protrusions of the pair of narrow inner plates 1b, 1b'. The end faces 1f of both sides of the narrow inner plates 1b, 1b' and the back surfaces of the pair of wide inner plates 1a, 1a' are connected to the pair of wide back up plates 2a, 2a', and the pair of narrow inner plates 1b, 1b' The back surface of the holder is pressed against a pair of narrow back-up plates 2b and 2b'.

As shown in FIGS. 2 and 3, each of the backup plates 2a, 2a', 2b, 2b' has vertical headers 20, . , 20 are formed, and lateral headers 21, .
Gas blowing ports 23, .

For each inner plate 1a, 1a', 1b, 1b', an independent gas supply pipe 24,..., 2 is provided from outside the mold.
4 are connected to the lowermost horizontal headers 21, ..., 21 via gas communication pipes 25, ..., 25, and the gas is distributed between the horizontal header 21 and the vertical header 20, and the gas inlets 23, ..., 23 From then on, it is introduced into the gap 9.

A rectangular cylindrical electromagnetic coil 9 is fitted into the outer periphery of the backup plate 2 assembled into a rectangular cylindrical shape as described above. And this electromagnetic coil 9 is
Each backup plate is supported from below by a bracket 2c' provided at the lower part of the back surface. Note that the portion 9a shown in FIGS. 2 and 3 is a connector portion of the electromagnetic coil 9. The above electromagnetic coil 9
As shown in the figure, the height of the back-up plate 2 is smaller than that of the back-up plate 2, and the upper and lower portions of the back-up plate 2 protrude from the electromagnetic coil 9 in the installed state.

As shown in FIGS. 1 and 6, an upper water passage box 8a is fixed to the upper back side of the pair of narrow back up plates 2b and 2b' with bolts 11, while a second , 6, the lower water passage box 8a is fixed with bolts 11. As shown in FIG. The fixed wall 8c of the upper water passage box 8a, which is in contact with the backup plates 2b, 2b', is provided with a water passage hole S27 communicating with the upper water passage hole S16 of the backup plates 2b, 2b'. Further, the fixed wall 8d in contact with the backup plates 2b, 2b' of the lower water flow box 8b is connected to the backup plates 2b, 2b'.
A water passage hole S15 is provided which communicates with the lower water passage hole S9 of b'.

As described above, the backup plate 2, which is provided with the electromagnetic coil 9 and the upper and lower water flow boxes 8a, 8a', 8b, and 8b' on its outer periphery, is held between the pair of holding frames 4a and 4b.

As shown in FIG. 3, the pair of sandwich frames 4a and 4b each have box portions 4c and 4d that form upper and lower water passages S4 and S7.
The end walls 4e of c and 4d are brought into contact with the top and bottom of the back surfaces of the pair of wide back up plates 2a and 2a', and are fastened by a total of four tie rods 10 on the top, bottom, left and right sides. As shown in FIGS. 2 and 5, each tie rod 10 has a bellows spring 6 interposed at both ends thereof, which is supported by a seat 10a.
That is, as described above, the narrow inner plates 1b and 1b' thermally expand in the width direction, and the wide back up plate 2
a, 2a' are slightly moved outward in the orthogonal direction, the pair of sandwiching frames 4a, 4b
However, by contracting the flat spring 6, they can expand each other.

Each sandwiching frame 4a, 4b has a plurality of water passages or water holes in addition to the above-mentioned upper and lower water passages S4, S7. That is, as shown in FIGS. 2 and 4, a water passage S4 formed at the upper part of the outer wall 4g of each sandwiching frame 4a, 4b, a water passage S5 communicating with the water passage S4, and a water passage S5 communicating with the water passage S5. It is provided with a water passage S6 which extends from top to bottom while being bent and communicates with the water passage S7. In FIG. 2, the right and left sides of the central axis O have different cross-sectional locations, but the waterway relationship is symmetrical with respect to the central axis O.
Each sandwiching frame 4a, 4b further includes an upper box portion 4.
The wide back-up plate 2 is attached to the end wall 4e of c.
Water hole S communicating with upper water hole S16 of a, 2a'
17, and the end wall 4e of the lower box portion 4d has a communication hole S8 communicating with the lower water passage hole S9 of the wide back up plate 2a, 2a'. Furthermore, water passages S19 are provided on both sides of the end wall 4e of the upper box part 4c, and water passages S11 are provided on both sides of the end wall 4e of the lower box part 4d.
communicates with the water passage S21 of the upper water passage box 8a via the block 7 having the water passage 20, while each of the water passages S11 communicates with the water passage S11 of the lower water passage box 8b via the block 7 having the water passage S12. It's communicating. The connection to the block 7 is made by using a sealing member such as a U-packet, for example, to connect the upper and lower water flow boxes 8a, 8b, the sandwiching frame 4a,
The seal is maintained even if the block 4b moves in a somewhat arbitrary direction relative to the block 7.

As described above, the pair of sandwiching frames 4a and 4b holding the backup plate 2 therebetween are attached to the pair of hanger frames 12a and 12b. The hanger frames 12a, 12b are designed to be installed on a mold mount (not shown) of continuous casting equipment.

Each sandwiching frame 4a, 4b has its side wall 4g fixed to the side wall 12c of the hanger frame 12a, 12b with a bolt 14. This condition is shown in FIG. However, this fixation is done so that the sandwich frames 4a, 4b can move slightly relative to the hanger frames 12a, 12b because the sandwich frames 4a, 4b move when the inner wall 1 thermally expands as described above. ing. That is, the bolt insertion holes 14a of the hanger frames 12a, 12b are made into elongated holes, and the bolts 15 are screwed into the side walls 4g of the sandwiching frame through the elongated holes 14a.
However, for the hanger frames 12a and 12b,
It is designed to be able to move slightly together with the sandwiching frames 4a and 4b.

In addition, the small back up plates 2b, 2
The upper water passage boxes 8a attached to each of b' are fixed to each hanger frame 12a, 12b by bolts 15. However, this fixation is similar to the case of the bolts 14 described above, so that when the inner wall 1 thermally expands, the upper water passage box 8a is pulled up by the back-up plate 2.
The bolt insertion hole 15a of the upper water passage box 8a is made into a long hole so that it can move together with b and 2b'.

Each of the pair of hanger frames 12a and 12b has a water passage box part 12d on its upper part, and has a plurality of water passages and water holes inside thereof.
Their arrangement is point symmetrical.

As shown in FIG.
A partition wall 12f is provided in the water passage boxes 12d of a and 12b to separate the water passages S2 and S25. One water passage S2 communicates with the water passage hole S1 for introducing cooling water, and also communicates with two water passages S2-1 and S2-2, respectively.
The water passages S2-1 and S2-2 communicate with water passages S3-1 and S3-2 provided on the side wall 12c, respectively, and the water passages S3-1 and S3-2 communicate with the sandwiching frame 4a, respectively. , 4b communicates with the water passage S4 provided in the side wall 4g. As clearly shown in FIG. 6, the other water passage S25 has a water passage hole S24 communicating with the water passage hole S23 provided in the upper water passage box 8a. It has a water passage hole S26 for discharging water.

The order in which the cooling water flows is as follows.

The cooling water flows through the water passage S2 through the water passage hole S1 in the water passage box 12b of each hanger frame 12a, 12b.
two water passages S2-1, S2-2
The water flows into the water passage S5 through the water passage holes S3-1, S3-2 and the water passage S4 of the sandwiching frames 4a, 4b. Then, it flows from the top to the bottom in the water passage S6, enters the water passage S4 in the lower water passage box 4c of each sandwiching frame 4a, 4b, and continues through the water passage S8 and the wide back up plates 2a, 2a'. Through the water hole S9, or through the water hole S11, the water flow path 12 of the block 7, the water flow paths S13, S14 of the lower water flow box 8b, the water flow hole S15, the water flow hole S9 of the small back up plate 2b, 2b'.
The water enters the lower part of the water passage S10 through the water passage S10, and continues to rise through the water passage S10, and the water flows through the water passage holes S16 of the wide back up plates 2a, 2a' and the upper water passage boxes 4c of the sandwich frames 4a, 4b. It enters the water passage S18 through the hole S17, while it enters the water passage S22 through the water passage hole S16 of the small back up plates 2b, 2b' and the water passage hole S27 of the upper water passage box 8a.
to go into. The cooling water in the water passage S18 flows through the water passage S1.
9. It enters the water passage S22 through the water passage S20 of the block 7 and the water passage hole S21 of the upper water passage box 8a. The cooling water in the water passage S22 is supplied to the water passage S22 through the water passage S22.
23 to the water passage hole S2 through the water passage hole S23 of the water passage box portion 12d of each hanger frame 12a, 12b.
5, and is subsequently discharged from the water passage hole S26.

The electromagnetic coil itself is cooled by making the winding of the coil hollow and letting cooling water flow through it.

Therefore, if the mold is constructed as described above, the rotating magnetic field generated by the electromagnetic coil 9 (electromagnetic stirring device) imparts fluid motion to the molten steel, improving the equiaxed crystallinity of the slab and improving its internal quality. be done.

In addition, by blowing inert gas through the porous plate 17, there is no sliding friction between each inner plate 1a, 1a', 1b, 1b' and the molten steel, and the molten steel is continuously transported in a flux-free and vibration-free state. It can be cast and has improved surface quality.

On the other hand, the inner plate is formed of a porous plate 17 having a porous layer, and a shielding plate 18 made of a good heat transfer material is provided on the outside of the porous plate 17.
are integrally connected, and both the plates 17, 1
Since a gap 19 is provided between the molds 8 and 8 for introducing gas, a mold with a simple structure, easy to manufacture and assemble, and with little damage and high durability can be obtained.

In addition, the gas-blown mold with a built-in electromagnetic stirring device has a structure in which the mold wall 1, the backup plate 2, etc. are not integrated and can be disassembled, and the backup plate 2 is held between the clamping frames 4a and 4b. An electromagnetic coil 9 is installed between the backup plate 2, the sandwich frames 4a and 4b, and the hanger frames 12a and 12b that support them.
Since the structure is such that it is interposed, assembly is very simple and it can be made relatively compact.

[Brief explanation of drawings]

Each figure shows a gas blowing mold with a built-in electromagnetic stirring device according to one embodiment of the present invention, and FIG. 1 shows the − of FIG. 4.
2 is a sectional view taken along the - line in Fig. 4; Figure 3 is a sectional view taken along the - line in Fig. 1;
The figure is a cross-sectional view taken along the - line in Figure 1, and Figure 5 is a cross-sectional view of Figure 1.
6 is a partial sectional view of FIG. 1. FIG. 1...Mold wall, 1a, 1a', 1b, 1b'...Inner plate, 2 (2a, 2a', 2b, 2b')...Backup plate, 4a, 4b...Pinch frame, 9
... Electromagnetic coil, 12a, 12b ... Hanger frame, 17 ... Porous plate, 18 ... Shielding plate,
19...Gap portion, 20...Vertical header, 21...
Lateral header, 23... Gas inlet, 24... Gas supply pipe, 25... Gas connecting pipe.

Claims (1)

[Claims] 1. A rectangular cylindrical mold wall is composed of four flat inner plates, each inner plate is made of a porous plate, and the outside of the porous plate is made of a good heat transfer material. The above-mentioned two plates are integrally connected by providing a shielding plate, and a gap is provided between the above-mentioned two plates for introducing an inert gas, while each of the above-mentioned inner plates is supported by each back-up plate. and butt the sides of each inner plate against each other,
Fasten the sides of each backup plate together;
Furthermore, the mutually fastened back up plates are sandwiched between a pair of sandwiching frames from both sides thereof, and the sandwiching frames are fastened to each other, and further, both sides of each of the sandwiching frames are connected to each of the pair of hanger frames. An electromagnetic coil is housed between a backup plate configured and mutually fastened, a pair of sandwiching frames and a hanger frame, and the electromagnetic coil is supported by a part of the outer periphery of the backup plate. A gas-blown mold with a built-in electromagnetic stirring device for continuous casting equipment.