JPH02205233A - Method for preventing leakage of molten steel in twin roll type continuous casting equipment and short weir - Google Patents

Abstract

PURPOSE:To prevent leakage of molten steel without using a plenty of gas by injecting oil at the prescribed pressure near boundary of the molten steel and each mold roll. CONSTITUTION:Molten steel basin 2 is formed with one pair of the mold rolls 1, 1 and short weirs 3 arranged at both end faces of both rolls 1, 1. In there, the development of leakage of the molten steel by invasion of the molten steel from gap between the mold roll 1 and the short side weir 3 is prevented. Then, a first porous member 5 is arranged near the boundary between the molten steel and each mold roll 1, 1 and from there, the oil is injected at the prescribed pressure. A second porous member 6 is arranged along an arc face at recessed face part of the first porous member 5 and from there, inert gas is injected at higher pressure than the oil pressure. By this method, the leakage of the molten steel can be economically prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for preventing leakage of molten steel in twin-roll continuous casting equipment and a short side weir.

BACKGROUND OF THE INVENTION As equipment for continuous casting of thin steel sheets, there is a twin-roll type equipment that uses a pair of mold rolls (hereinafter simply referred to as rolls) to pull out a slab from between the two rolls. In this twin roll type continuous casting equipment, as shown in FIG. 11, short side weirs 103 are arranged at both ends of each roll 101 in order to form a molten steel reservoir 102 above between both rolls 101. . Conventionally, in order to prevent leakage of molten steel, this short side weir 103 is connected to the roll 10.
Although the first side is pressed with a considerable force, a gap inevitably forms between the two sides due to the thermal effect, and molten steel enters this gap, causing cracks and deterioration of the shape of the slab. This caused destruction of the sliding parts of the weir, causing casting to stop. By the way, as a solution to this drawback, Japanese Patent Application Laid-Open No. 62-1
There is a publication No. 24053. In this device, a gap is formed between the short side weir and the roll, and gas is ejected into this gap to form a gas film and prevent the occurrence of flakes.

Problems to be Solved by the Invention However, the conventional structure described above is uneconomical because it uses a large amount of gas, and there are also problems in that bubbles are generated on both sides of the cast slab.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a method for preventing leakage of molten steel in twin-roll continuous casting equipment and a short side weir that can solve the above-mentioned problems.

Means for Solving the Problems In order to solve the above problems, a first means of the present invention includes a pair of mold rolls, and a method of forming a molten steel reservoir above between the two mold rolls by disposing them on both end faces of the mold rolls. This is a molten steel leakage prevention method that prevents molten steel from entering through the gap between the short side weir and the molten steel in twin-roll continuous casting equipment, in which oil is spouted at a predetermined pressure near the boundary between the molten steel and each mold roll. This is a leak prevention method.

The second means is a short side weir which is disposed on both end faces of a pair of mold rolls and forms a molten steel reservoir above between both mold rolls, and has a short side weir on the mold roll side surface of the weir body.
A first porous member having a predetermined width is provided in an arc shape along the vicinity of the boundary between the molten steel and the mold roll.
A second porous member is provided along the arc surface on the concave side of the porous member, a sealing member is provided along the concave side of the second porous member, and oil at a predetermined pressure is applied to the mold roll side surface of the first porous member. An oil supply pipe for spouting is connected to the first porous member, and a gas supply pipe for spouting inert gas at a pressure higher than the pressure of the oil is connected to the mold roll side surface of the second porous member. This is a short side weir in a twin-roll continuous casting facility characterized by being connected to a second porous member.

Further, in the second means, a third means is provided on the surface of the snout portion of the weir body provided over a predetermined height from a position near the closest portion between both mold rolls and between both box 1 porous members. A third porous member is provided in a portion facing the molten steel reservoir, and a high pressure oil supply pipe for spouting high pressure oil higher than a predetermined pressure onto the molten steel reservoir side surface of the third porous member is connected to the third porous member. This is a short side weir in twin-roll continuous casting equipment that is characterized by the following.

Effects According to the first means, oil is ejected into the gap between the mold roll and the short side weir to prevent molten steel from entering, so a large amount of gas is not used as in the conventional method. Further, according to the second means, the oil for preventing molten steel leakage that is ejected from the first porous member is prevented from being lost by the inert gas that is ejected from the second porous member, and this gas is also prevented by the sealing member. Since it is sealed, it is very economical. Furthermore, according to the third means, high-pressure oil is ejected from the nose of the weir body, which is provided over a predetermined height from a position near the closest point between both mold rolls, through the third porous member, so that the oil solidifies. It is possible to prevent the slab from seizing at the confluence of the shells, reduce sliding resistance, and prevent large bulges.

Example Embodiments of the present invention will be described below based on the drawings.

First, a first embodiment of the present invention will be described based on FIGS. 1 and 2.

In Figures 1 and 2, 1 is a pair of mold rolls (hereinafter simply referred to as rolls) arranged parallel to each other.
Short side weirs 3 for forming a molten steel reservoir 2 above between these rolls 1 are arranged on both end faces of the rolls 1. Each of these short side weirs 3 has a weir body 4 made of refractory material and having a substantially inverted trapezoidal shape, and a crotch on the surface of the weir body 4 on the roll 1 side and at the boundary between the molten steel A and the roll 1. A first porous member (made of A1203, SiC or graphite may be used) 5 is arranged in an arc shape with a predetermined width, and the first porous member 5 is also placed on the roll 1 side surface of the weir body 4. A second porous member (made of A1203) 6 arranged along the arcuate surface of the concave side, and also on the surface of the weir body 4 on the roll 1 side, and on the arcuate surface of the second porous member 6 on the concave side. A sealing porous member (an example of the sealing member is made of Al2O3, and may also be SiC or graphite) 7 disposed along the first
A first oil supply pipe 8 is connected to the porous member 5 to spray oil at a predetermined pressure onto the roll 1 side surface, and a first oil supply pipe 8 is connected to the second porous member 6 to spray oil at a predetermined pressure onto the roll 1 side surface. Also, high pressure inert gas (e.g. Ar gas, N
2 gas), and a second oil supply pipe 10 connected to the sealing porous member 7 and spouting oil at a predetermined pressure onto the surface of the roll 1.

Note that as the above-mentioned parts and gases, those shown in the table below are used.

In the above configuration, when performing continuous casting, oil and gas are first supplied to each porous member 5, 6.7 under the conditions shown in Table 1 above. Then, as shown in FIG. 2, oil at a predetermined pressure is ejected from the surface of the first porous member 5 toward the boundary between the roll 1 and the molten steel A, causing the molten steel A to flow toward the roll 1 side. Leakage or intrusion can be reliably prevented. This oil is prevented from flowing out to the outside by the gas ejected from the adjacent second porous member 6. Further, the gas is sealed by the oil ejected from the sealing porous member 7.

In addition, the oil ejected from the first porous member 5 not only prevents leakage of molten steel, but also carbonizes due to the high temperature of the molten steel and does not serve as a buffer material between the roll 1 and the short side weir 3. Also, between the short side weir 3 and the solidified shell B, it acts as a lubricant to protect the solidified shell B that has just been generated.

In addition, the gas pressurizes the oil to enhance the sealing effect, but due to the roughness of the finish on the end surface of the roll 1 and the end surface of the roll 1 of the short side weir 3 or the slight inclination of the roll 1, the difference between the roll 1 and the short side weir 3 may Even if the gap widens instantaneously, the pressure of the oil is maintained by the gas pressure ejected from the second porous member 6, thereby preventing leakage or intrusion of molten steel.

In addition to preventing gas leakage, the oil in the first porous member 5 also has the role of reducing the sliding resistance between the roll 1 and the short side weir 3 and suppressing fluctuations in the load torque of the roll 1.

Furthermore, porous member 5. E3. The average filling degree of 7 is, for example, 97% for the first porous member 5, 95% for the second porous member 6, and 98.5% for the sealing porous member 7.
are used. In addition, each porous member 5, 8
．． The degree of porosity of 7 has a slope. That is, the degree of porosity is high on the oil and gas supply side, and low on the ejection side.

Next, a second embodiment, which is more specific than the first embodiment, will be described as a third embodiment.
This will be explained based on the diagram and FIG.

In Figures 3 and 4, 21 indicates molten steel A and roll 2.
An arc-shaped embedded member (for example, made of a highly hard ceramic material) is embedded in the surface of the weir body 23 so as to span the boundary between the roll 22 and the first groove 24. , a second groove 25 and a third groove 26 are formed, and a first porous member 27 is formed in the first groove 24, and a second groove 26 is formed in the first groove 24.
A second porous member 28 is inserted into the groove 25, and a gasket (sealing member) 29 is inserted into the third groove 26.

Further, the embedded member 21 includes a second porous member 2 for supplying oil to the first porous member 27, and a second porous member 2 for supplying oil to the first porous member 27.
A plurality of holes 30, 31 are formed at predetermined intervals for supplying an inert gas (for example, Ar gas, N2 gas) to 8. Note that each of the above-mentioned members 21, 27, and 28 is divided into a plurality of pieces for manufacturing purposes.

In the above structure, oil at a predetermined pressure is ejected from the first porous member 27 to prevent leakage of molten steel, and gas is ejected from the second porous member 28 to prevent oil from flowing out. This gas is Patsukin 29
Seal is done by.

Note that in the second embodiment, the first porous member 2
Although the porous member 7 is configured to have a long arc shape, the first and second porous members 27 and 28 may be divided into a plurality of pieces in the longitudinal direction, as shown in FIG. 5, for example. Furthermore, the sixth
As shown in the figure, a plurality of first porous members 27 may be arranged in a cylindrical (or conical) shape.

Next, a third embodiment will be described based on FIGS. 7 and 8. The weir body 42 of the short side weir 41 in this embodiment includes a short side snout portion 44 provided over a predetermined height from a position near the closest portion of both rolls 43, and an upper weir body 45 disposed above this. It is composed of. Further, as explained in the second embodiment, the upper weir body 45 and the short side snout portion 44 include first porous members 4B and 47 for spouting oil to prevent leakage of molten steel, and a first porous member 47 for preventing the above portion from being washed away. second porous members 48, 49 for gas ejection, and sealing porous members (seal members) 50, 51 for oil ejection for sealing the gas; Between the first porous members 47 and 47 on both sides of 44, an inverted trapezoidal third porous member 52 for spouting high pressure (for example, 30 kg/cJ) oil to the molten steel A side is provided. A high pressure oil supply pipe for supplying high pressure oil is connected to this third porous member 52.

In this configuration, when high-pressure oil is ejected from the third porous member 52 of the short side nose tip 44 toward the molten steel A side,
It is possible to prevent the slab C from seizing that occurs at the confluence of the solidified shells B, to reduce sliding resistance, and to prevent large bulges.

Next, a fourth embodiment will be described based on FIGS. 9 and 10.

In each of the above embodiments, the oil for preventing leakage of molten steel was spouted from the short side weir side, but in this embodiment,
It is designed to be ejected from the roll side. That is,
A large number of oil supply holes 62 are formed at predetermined intervals on the inner side of each roll 61, and the same number of oil spout holes 63 are formed on the outer side, and holes 62. The oil spout holes 63 facing the weir body 65 are connected to each other by communication passages 64 (only five are shown in the drawing, but of course they all communicate with each other). In order to supply oil, supply members 65 for supplying oil to the same number of oil supply holes 62 are arranged on the side of the roll 61. Of course, this case also has the same effects as the above embodiments.

Effects of the Invention As described above, according to the first means of the present invention, in order to prevent molten steel from entering the gap between the mold roll and the short side weir, oil is jetted out, so that unlike the conventional method, gas and The difference is that large amounts of gas are not used. According to the second means, the second porous member for spouting inert gas is provided along the first porous member for spouting oil for preventing leakage of molten steel, so it is possible to prevent oil from flowing out and Since the inert gas is sealed by the sealing member, it is very economical. Furthermore, according to the third means, a third porous member is provided that spouts high-pressure oil from the nose of the weir body, which is provided over a predetermined height from a position near the closest point between both mold rolls, so that the solidified shell It is possible to prevent the slab from seizing that occurs at the merging part, reduce sliding resistance, and prevent large bulges.

[Brief explanation of the drawing]

1 and 2 show the first embodiment of the present invention. FIG. 1 is a rear view of the short side weir, and FIG.
I sectional view and FIGS. 3 to 6 show the second embodiment of the present invention, FIG. 3 is a partial front view of the short side weir, and FIG. 4 is a sectional view taken along the line ■-■ of FIG. 3. , FIG. 5 and FIG. 6 are partial front views showing a modification of FIG. 3, and FIG. 7 and FIG.
Fig. 7 is a front view of the short side weir seen from the molten steel side reservoir side, Fig. 8 is a sectional view taken along III-III in Fig. 7, and Figs. 9 and 10 are views of the present invention. 9 is a side view of the roll, FIG. 10 is a side view showing the arrangement of holes formed in the roll, and FIG. 11 is a partially cutaway side view of the conventional example. 1... Roll, 2... Molten steel reservoir, 3... Short side weir, 4... Weir body, 5... First porous member, 6... Second porous member. Members, 7... porous member for sealing, 8... first oil supply pipe, 9... gas supply pipe, 10... second oil supply pipe, 22... roll, 23... Weir body, 27... First porous member, 28... Second porous member, 29... Packing, 41... Short side weir, 42... Weir Main body, 43
... Roll, 44 ... Short side nose tip, 46.47
...First porous member, 48°48...Second porous member, 50.51...Porous member for sealing, 52...Third porous member, el...Roll, θ2...Oil supply hole, 83...Oil spout hole, 64
...Communication path.

Claims (1)

[Claims] 1. Preventing molten steel from entering through the gap between a pair of mold rolls and short side weirs that are arranged on both end faces of these mold rolls and form a molten steel reservoir above between both mold rolls. A method for preventing leakage of molten steel in twin-roll continuous casting equipment, the method comprising jetting oil at a predetermined pressure near the boundary between the molten steel and each mold roll. 2. A short side weir arranged on both end faces of a pair of mold rolls to form a molten steel reservoir above between the two mold rolls, with a short side weir on the mold roll side surface of the weir body near the boundary between the molten steel and the mold rolls. A first porous member having a predetermined width is provided in an arc shape along the concave side of the first porous member, a second porous member is provided along the concave side of the first porous member, and a sealing member is provided along the concave side of the second porous member. An oil supply pipe for spouting oil at a predetermined pressure onto the mold roll side surface of the first porous member is connected to the first porous member, and the oil supply pipe is connected to the mold roll side surface of the second porous member. A short side weir in a twin-roll continuous casting equipment, characterized in that a gas supply pipe for spouting inert gas at a pressure higher than that of the second porous member is connected to the second porous member. 3. A third porous member is placed on the surface of the snout portion of the weir body, which is provided over a predetermined height from a position near the closest portion between both mold rolls, and on a portion facing the molten steel reservoir between both first porous members. The twin according to claim 2, further comprising a high-pressure oil supply pipe connected to the third porous member for spouting high-pressure oil higher than a predetermined pressure onto the molten steel reservoir side surface of the third porous member. Short side weir in roll type continuous casting equipment.