JPH07112602B2 - Twin dam type continuous casting machine side dam - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a side dam of a continuous casting device including a pair of belts.

[Conventional technology]

In recent years, attention has been focused on a technique for directly and continuously casting a metal strip having a thickness of several tens of millimeters, which is close to the final shape, from a molten state. When this technique is used, the hot rolling process is not required and the rolling to the final shape may be light, so that the process and equipment can be simplified.

The twin belt method is known as one of such continuous casting techniques.

In this method, a pair of cooling belts rotating in opposite directions are vertically arranged, and the molten metal is supplied to a space defined by the pair of cooling belts and side dams. The molten metal supplied here is solidified by cooling and solidifying the portion in contact with the cooling belt. This coagulation shell
Grows all around while moving with the rotation of the cooling belt,
It is separated from the belt when it joins the metal belt.

FIG. 6 shows an overall view of the twin belt type continuous casting apparatus. In the casting method using this device, first, the molten metal 15 is stored in the molten metal supply nozzle 16 located at the upper part of the device.

On the other hand, the pair of belts 12 that are water-cooled with the cooling water 14 and the pair of side dams 10 have their surfaces facing each other synchronized, and rotate downward. Cooling water 14 is allowed to flow on the back surface of the belt 12. When the molten metal 15 is supplied to the portion surrounded by the pair of belts 12 and the pair of side dams 10, the solidified slab is pulled out from the lower end of the apparatus at a speed synchronized with the rotation of the belts.

[Problems to be Solved by the Invention]

As shown in FIG. 3, the side dam 10 in the above-mentioned conventional apparatus is provided with a solid block 1 of a rectangular parallelepiped made of copper, and heat mainly flows in only from the contact surface 5 thereof while in contact with the molten metal. As a result, only the surface side of the block thermally expands in the block, and the entire block undergoes a fan-shaped deformation as shown by a line 8 to a line 8 in FIG. As a result, the block and the upper and lower blocks connected thereto come into line contact only at the upper and lower corners on the molten metal side, and the pressing force and other impact forces applied to all the blocks cause the second block. A permanent set is produced as shown by line 9 in the figure. Further, the compressive thermal stress acting on the molten metal surface side of the block causes the same deformation.

This permanent strain causes the block to move away from the slab as it rotates, and when it comes into contact with the next new molten metal, it creates a gap between adjacent blocks, where the molten metal penetrates. There, the phenomenon of solidification occurs. This phenomenon makes it difficult for the slab and block to slide due to the difference in thermal expansion, and for the smooth separation of the block and slab, making casting impossible.

4 and 5 show a deformed state when continuous casting is performed using a conventional side dam.

FIG. 5 shows a state where the block 1 of the side dam before the permanent deformation has been thermally deformed, and the heating from the side of the molten metal 13 causes thermal expansion only on the molten side of the side dam.
The lower blocks are in line or point contact on the melt side. The contact area is also designed to prevent leakage of molten metal.
It also receives pushing force from the vertical direction. For this reason, compressive stress is generated in the vertical direction in the same portion, and permanent deformation particularly occurs in the corner portion 1a on the melt side.

FIG. 4 shows a state immediately after the side dam of FIG. 5 leaves the solidification shell, is once cooled, and is immersed in a new molten metal. Since the vicinity of the melt-side corner 1a of the side dam is deformed as shown by the line 9 in FIG. 2, the melt 13 is inserted into this portion and solidification occurs there. When such solidification occurs, when the solidification shell and the side dam are separated at the lower end of the casting device,
The two cannot be separated smoothly and the operation of the device becomes impossible.

The present invention is intended to provide a side dam for a continuous casting apparatus that solves the above problems.

[Means for Solving the Problems]

According to the present invention, in a side dam of a continuous casting apparatus equipped with side blocks that abut on both ends of a pair of belts arranged in parallel to form a pool of water, a hole is provided inside the side block and a heat medium is enclosed in the hole. did.

[Action]

In the present invention, since the heat pipe is formed in the side block by the hole in which the heat medium is sealed, when the molten metal comes into contact with the side block forming the side dam and its heat flows into the side block, The heat flowing in due to the heat transport action is transported to the opposite side of the molten metal in the block, and the temperature distribution in the side block becomes uniform. Therefore, the fan-shaped deformation due to the temperature difference does not occur in the side block, and the thermal stress in the side block does not occur. As a result, there is no permanent deformation of the corners caused by one-sided contact of the mutually connected blocks and permanent deformation due to thermal stress. Is formed, which prevents the molten metal from pouring.

〔Example〕

An embodiment of the present invention will be described with reference to FIG. Reference numeral 1 is a copper side block that constitutes a side dam, and is provided with a plurality of drill holes 2 from the surface 5'opposite to the surface 5 in contact with the molten metal.
(4 drill holes are shown in the figure) are drilled horizontally such that the distance from the bottom surface to the side block surface 5 is a distance of 4. The distance 4 is set to a thickness (for example, 2 to 3 mm) that does not cause a problem in strength during use. The hole 2 is filled with a heat medium, for example, 20% of the volume of the hole 2, and the sealing medium 3 is welded to the open end of the hole 2 while boiling the heat medium. It is enclosed in the hole 2. The arrow 10 indicates the connecting direction of the side blocks 1 connected vertically. The total cross-sectional area of the plurality of holes 2 is suitably about 50% of the cross-sectional area of the side block 1, and the diameter of the holes 2 is suitably about 10 mm.

In the present embodiment, the hole 2 in which the heat medium is sealed as described above has a function of a heat pipe, and when the side block 1 moves downward in the connecting direction 10 and comes into contact with the molten metal, the surface 5 is removed from the molten metal. The heat that has flowed into the side block 1 via the above is carried to the opposite surface 5'side by the convection of the enclosed heat medium and its vapor, and the temperature difference between both sides of the side block 1 is reduced. As a result, when the side block 1 receives heat from the molten metal, both sides are vertically expanded by substantially the same length as indicated by a line 7 in FIG. The entire upper and lower surfaces are in contact with each other, so that the permanent deformation of the corner portion due to the partial contact of the side block and the permanent deformation due to thermal stress are prevented. Therefore,
When the side blocks 1 come into contact with the molten metal again, there is no gap between the side blocks adjacent to each other, the molten metal pouring is prevented, and the situation where the device is inoperable due to the pouring can be avoided.

In this embodiment, a plurality of holes 2 having a diameter of 10 mm are provided so that the area ratio is 50% with respect to the cross-sectional area of the copper side block 1, and 20% of the volume of the holes is filled in the holes 2. Has a heat transfer rate of about 10 for solid copper of the same cross section.
The heat transport amount of the side dam as a whole is about 50 times that of the solid copper side dam. Therefore, in this case, the temperature difference in the horizontal direction of the side dam is 1/50 of that of the conventional solid copper side dam, and the problem of thermal deformation is solved.

In the present invention, the cross-sectional shape of the hole formed in the side dam can be appropriately selected, but since heat transfer by steam plays an important role, it is desirable to provide the hole in a substantially horizontal direction.

〔The invention's effect〕

The present invention can eliminate the high temperature difference between the molten metal side of the side block and the opposite side by enclosing the heat medium in the hole provided inside the side dam constituting the side dam,
As a result, it is possible to prevent the upper and lower ends of the blocks on the molten side of the blocks from being permanently deformed, which may cause the brazing between the blocks, so that the twin-belt continuous casting apparatus can be operated for a long period of time.

[Brief description of drawings]

FIG. 1 is a perspective view of an embodiment of the present invention, FIG. 2 is an explanatory view showing the shape of the same embodiment and a conventional side block at the time of thermal deformation, and FIG. 3 is a perspective view of the conventional side block. Fig. 4 shows the state of the conventional side block immediately after being immersed in the molten metal. Fig. 4 (A) is its front view, Fig. 4 (B) is its side view, and Fig. 5 is the conventional side block permanently deformed. FIG. 6A is a front view of the same, FIG. 6B is a side view of the same, and FIG. 6 is an explanatory view of a twin belt type continuous casting apparatus. 1 ... Side block, 2 ... Hole, 3 ... Sealing plug, 5 ...
… Side block side of melt side, 5 '…… Side block side opposite to melt, 12 …… Belt.

Claims (1)

[Claims] 1. A side dam of a twin-belt type continuous casting apparatus equipped with side blocks for contacting both ends of a pair of belts arranged in parallel to each other to form a pool of molten metal, wherein holes are provided inside the side blocks. Side dam of twin-belt type continuous casting equipment characterized by containing a medium.