JPH0716769B2 - Side weir of twin drum type continuous casting machine - Google Patents

Description

The present invention relates to a side weir of a twin-drum type continuous casting machine.

[Conventional technology]

The twin-drum type continuous casting machine has an axial shaft as shown in FIGS. 3 (a) and 3 (b), which are a plan view and a front view, respectively.
Side dams S1 and S2 are provided on both end faces e1 and e2 of a pair of drums R1 and R2, in which a1 and a2 are parallel and arranged at a distance d corresponding to the thickness of the slab.
To form a bottomless mold. The side dams S1 and S2 are indispensable for sealing the molten metal M (hatched portion) between the drums R1 and R2. Generally, such a side weir, as disclosed in Japanese Utility Model Application No. 61-186136, faces a heat insulating member, a base member implanted in the heat insulating member, and a drum of the base member in a side weir case. It is configured to accommodate the ceramics implanted on the side of the drum, and the ceramics comes into contact with the end surface of the drum to seal the molten metal.

Since the ceramics constitutes a part of the mold surface, thermal deformation occurs due to the heating for preventing the metal adhesion from the molten metal and the heat from the molten metal. In order to improve the molten metal sealing performance of the side dam, it is necessary to minimize such thermal deformation of the ceramic surface that contacts the drum. A major factor in inducing thermal deformation of the ceramic surface is warpage due to the temperature difference between the front and back sides of the base member. For this, as disclosed in Japanese Patent Application No. 62-140593, There is a method of heating by heating the entire base member uniformly with a heater provided inside.

In addition, as a factor of thermal deformation of the ceramic surface, warpage of the side weir case can be mentioned.
As disclosed in 88043, there is a method of cooling the steel skin on the back surface of the side weir.

However, even if the warpage of the base member or the back iron skin can be eliminated by the method of the above publication, it is possible to eliminate the warpage caused by the temperature difference between the front and back surfaces of the heat insulating material installed between the base member and the back iron skin. Can not. When a warp occurs in the heat insulating material, the base member implanted in the heat insulating material is pushed up, and as a result, the ceramic surface in contact with the drum is deformed,
There was a problem that the molten metal sealing performance, which is the original function of the side dam, was impaired.

[Problems to be Solved by the Invention]

INDUSTRIAL APPLICABILITY The present invention is a twin drum continuous type in which a warp of a heat insulating material is eliminated in a side weir having a heater provided in a base member to prevent thermal deformation of a ceramic surface in contact with a drum and improve molten metal sealing performance. The purpose is to provide a side weir for a casting machine.

[Means for Solving the Problems]

According to the present invention, the above object is a side weir of a twin drum type continuous casting machine in which a bottom weir is formed by pressing side weirs on both end faces of a pair of drums whose axes are arranged in parallel with each other, and A heat insulating material, a base member planted in the heat insulating material, and a ceramic that is planted on a side of the base member facing the drum and is in contact with the drum end surface; Twin drum type continuous casting, characterized in that, in a side dam having a heater for heating the base member provided inside the member, a slit having at least the base member side opened is provided at the center of the plate surface of the heat insulating material. Achieved by the side weir of the machine.

[Action]

A conventional side weir having a heater provided on a base member is shown in FIGS. 2 (a) and 2 (b). 2 (a) is a front view seen from the side dam drum side, and FIG. 2 (b) is a cross-sectional view taken along line BB of FIG. 2 (a).

The side dam 1 includes a heat insulating material 5, a base member 6 planted in the heat insulating member, and a ceramic 7 planted in the base member in a side dam case 4 composed of a frame plate 2 and a bottom plate 3. The heater 8 is housed and the heater 8 is provided in the through hole in the base member 6. Base member 6 with heater 8
When is heated, a temperature gradient occurs in the thickness direction in the heat insulating member 5 between the front surface side (base member 6 side) and the back surface side (bottom plate 3 side). That is, since the front side has a relatively higher temperature than the back side, the thermal expansion on the front side becomes relatively larger than the thermal expansion on the back side. A warp occurs in which the central part of the is convex toward the base member side. Here, assuming that the length of the heat insulating material 5 is L, the thickness is h, the thermal expansion coefficient is α, and the temperature difference between the front surface and the back surface of the heat insulating material is ΔT, the following equation is obtained in the length L direction of the heat insulating material 5. A thermal expansion difference ΔL represented by (1) occurs.

ΔL = L × α × ΔT (1) On the other hand, if the radius of curvature of the warp caused by the expansion of the front surface of the heat insulating material by ΔL is r, and the arc angle at that time is θ, the rise H of the warp is calculated by the following geometry. It is obtained from the physical relationships (2) to (5). That is, From the relationship And also From the relationship Is obtained as.

That is, the heat insulating material pushes up the base material by the amount of H, and as a result, the ceramic surface that contacts the drum is deformed.

According to the present invention, a slit is provided in the center of the plate surface of the heat insulating material 5, and the thermal expansion ΔL is absorbed in the slit to prevent the heat insulating material from warping.

The slit is provided in the central portion of the plate surface of the heat insulating material 5 because the shape of the warp to be prevented is such that the central portion of the plate surface is convex toward the base member side.

The slit of the present invention needs to be opened at least on the base member 6 side (front side). This is to absorb the thermal expansion on the front surface side, which is relatively larger than that on the rear surface side, by the slit to eliminate the difference in thermal expansion between the front surface and the back surface. Since the thermal expansion on the back side as well as the front side may be absorbed, the openings may be formed on the back side as well as the front side. That is, in the former case, it is a recess or groove type slit provided on the surface (front surface) of the heat insulating material 5 on the base member 6 side, and in the latter case, the heat insulating material 5 is the base member 6 side (front surface side). To the bottom plate 3 side (rear surface side) in the thickness direction.

The shape of the slit should be a shape that is advantageous for absorbing the thermal expansion ΔL, and generally a slender linear shape is desirable.

The size and number of slits are set so that the thermal expansion ΔL can be absorbed.

Generally, the warp of the heat insulating material 5 includes components in the vertical direction and the horizontal direction, so the slits should be arranged so as to absorb both of these deformation components.

The type, shape, size, number and arrangement of slits are determined according to the needs of each side weir.

One of the desirable embodiments of the slit of the present invention is a groove-shaped slit provided in the center of the plate surface on the front surface of the heat insulating material in a cross shape or in a radial shape.

It is convenient to form the slit of the present invention as follows, for example.

In many cases, castable is used as the heat insulating material, and heat treatment is performed at a temperature of, for example, about 300 ° C. to dry the side weir in the process of manufacturing the side weir. When constructing the castable in the outer case, a plastic plate made to have dimensions of width, thickness and length that can absorb the thermal expansion ΔL of the castable used is embedded in advance in a position corresponding to the arrangement of the slits. The plastic plate is heated to disappear by the above-mentioned dry heat treatment. As a result, slits are formed in the heat insulating material with a predetermined size, shape, and arrangement. The plate to be embedded in advance need not be limited to a plastic plate, and may be a plate made of a material that disappears during the dry heat treatment.

In the above example, the embedded plate was extinguished by the castable dry heat treatment performed at about 300 ° C, but even if it does not disappear at the dry heat treatment temperature, it is heated by the heater heating in the base member at about 1200 ° C, which is higher temperature before the start of casting. You may make it disappear.
In that case, a plate made of a material that needs a high temperature to disappear may be embedded.

Further, the inside of the slit provided in the heat insulating material does not necessarily have to be a complete void, and a contractible substance that does not prevent absorption of thermal expansion of the heat insulating material by the slit may remain or be filled.

Hereinafter, the present invention will be described in more detail with reference to Examples.

〔Example〕

1 (a) and 1 (b) show an example of the side weir of the present invention. FIG. 1 (a) is a front view of the side weir seen from the drum side, and FIG. 1 (b) is a sectional view taken along the line AA in FIG. 1 (a).

In addition to the structure of the conventional side weir of FIG. 2, the side weir 1'has a slit 9 formed in a cross shape in the central portion of the plate surface. The size of this slit is 4mm wide, 20mm deep,
Length 300 mm, lateral slit width 4 mm, depth 20 mm, length 200 mm
And The heat insulating material has a length (L) of 500 mm and a thickness (h) of 40 mm.

The above side weir was fixed on a pedestal and heated by a heater in the base member so that the back surface of the base member was 1250 ° C.
Under this condition, the amount of deformation of the ceramic surface in the vertical direction (direction of the length L of the heat insulating material) was measured by an operating transformer.

For comparison, the conventional side weir of FIG. 2 was also measured by the same method under the same conditions.

As a result of the measurement, in the conventional side weir without slits in the heat insulating material, the ceramic surface vertical deformation of 0.8 mm occurred, whereas in the side weir of the present invention with slits in the heat insulating material, the ceramic surface vertical direction The amount of deformation is 0.2 mm, which is 1/4 that of the conventional type.

As a result, in the side weir of the present invention, the warp of the heat insulating material was substantially eliminated, and the molten metal sealing performance was significantly improved as compared with the conventional side weir.

〔The invention's effect〕

As described above, according to the present invention, by eliminating the warp of the heat insulating material of the side weir provided with the heater in the base member, it is possible to prevent thermal deformation of the ceramic surface in contact with the drum, The molten metal sealing performance of the side dam is significantly improved.

[Brief description of drawings]

1 (a) and 1 (b) show an example of a side weir according to the present invention, FIG. 1 (a) is a front view and FIG. 2 (b) is a sectional view, and FIGS. 2 (a) and (b) are conventional side weirs. (A) Front view and (b) sectional view showing the weir, and FIGS. 3 (a) and (b) show a state in which the drum and the side weir of the twin-drum type continuous casting machine form a mold. It is a (a) top view and a (b) front view. 1,1 ': Side weir, 2: Frame plate, 3: Bottom plate, 4: Side weir case, 5: Heat insulating material, 6: Base member, 7: Ceramics, 8: Heater, 9: Slit, S1, S2: Side Weir, R1, R2: drum, a
1, a2: drum axis, e1, e2: drum end surface, d: drum spacing.

Claims (1)

[Claims] 1. A side weir of a twin drum type continuous casting machine in which a side weir is pressed against both end faces of a pair of drums whose axes are arranged in parallel to each other to form a bottomless mold, wherein a heat insulating material is provided in an outer case. A base member planted in this heat insulating material,
In a side weir, which is provided on the side of the base member facing the drum and contains ceramics in contact with the drum end surface, and in which a heater for heating the base member is provided in the base member, A side dam of a twin-drum type continuous casting machine, characterized in that a slit having an opening at least on the base member side is provided in the center of the plate surface of the heat insulating material.