JP2002248546A - Side bank for twin-drum continuous casting machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To extend the life of a side bank of a twin-drum continuous casting machine, and to prevent a molten metal from leakage caused by a damaged refractory, by preventing joints between the refractory of the side bank from opening and the lower end of the refractory from breaking off. SOLUTION: The side bank 10 is constructed such that a plurality of random- shaped refractory 12 enclosed in a metal case 11 is covered by vertical piles of a plurality of base members 13 and ceramic plates 18 in this order. In this side bank, a receiving brick 14 is installed between the lower ends of the refractory 12, the base member 13 and the ceramic plate 18 and the side plate 11b of the metal case. The installation of the receiving brick 14 prevents the refractory joints from opening and the bottom ends of the base member 13 and the ceramic plate 18 from breaking-off through the downward pushing force generated by the base member 13 and the ceramic plate 18, working at the drum end face. A chamfer made at the bottom end of the ceramic plate 18 makes the prevention from the breaking-off more effective.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a side weir of a twin-drum continuous caster for producing a thin strip directly from a molten metal.

[0002]

2. Description of the Related Art As shown in FIG. 4, a twin drum type continuous casting machine has a pair of cooling drums 1 rotating in opposite directions.
And a metal melt e is continuously supplied to a pool 3 formed by a pair of side weirs 2 pressed against both end surfaces of the cooling drum by a pressing device (not shown), and the metal melt e is cooled. Cooling is performed on the peripheral surface of the drum 1 to form a solidified shell, and the solidified shell is pressure-bonded and integrated at the closest part of the cooling drum to manufacture a thin strip slab c.

[0003] The side weir 2 is indispensable for sealing the molten metal e in the pool 3, and generally,
For example, FIG. 5 disclosed in Japanese Utility Model Laid-Open Publication No. 63-90548
It is configured as shown in FIG.

That is, the side weir 2 comprises a bottom plate 4a and a side plate 4b.
A metal case 4, a refractory material 5 housed in the metal case, a base member 6 implanted in the refractory material, and a heater 8 built in the base member.
And a ceramic plate 7 implanted in the base member. It is also known that a stiffener (not shown) for preventing thermal deformation is attached to the back of the bottom plate 4a of the metal case.

During casting, it is necessary to prevent molten metal from leaking from between the side weir and the end surface of the rotating cooling drum.
For this purpose, it is necessary that the side weir be in close sliding contact with the end face of the drum, and that the side weir have a shape that is sufficiently adapted to the end face of the drum. Further, as shown in FIG. 6, when the lower end of the ceramic plate 7 is broken, the lowermost position of the ceramic plate 7 moves upward, and the arc length becomes substantially shorter, so that the solidification of the end of the slab C is ensured. If the chip is broken to the extent that it cannot be performed, the molten steel will leak out.

[0006]

However, even when the above-mentioned side weir is used, molten metal may leak, particularly when casting is performed for a long time. If molten metal leaks once, the condition continues, and the side weir loses its function in a short time, making it impossible to continue casting.In addition, casting burrs occur at both ends of the slab. Or the molten steel seeps out from the ends and impairs its shape. Furthermore, the casting burrs cause damage to the slab transport line and the rolling mill provided in the slab transport line, and meandering is apt to occur during transport, and the meandering causes the slab winding shape to be disordered.

As a result of a close investigation of the state of the side weir after casting, the present inventors have found, as shown in FIG. 5 (b), a slightly open joint between the ceramic plate 7 and the base member 6. m was generated, and it was found that the molten metal had penetrated into the joint opening m and reached the back surface of the base member 6 to become a metal. The metal at the joint opening is caught between the drum end surface and locally wears the ceramic plate 7, and the metal at the back of the base member 6 displaces the base member. As a result, poor sealing and leakage of molten metal occur. Thought it would happen. Further, as a result of investigating the side in another casting in which the molten metal leaked severely, FIG.
As shown in (b) and (d), the ceramic plate 7
At the lower end of the base member 6 and the lower end of the base member 6. If the ceramic plate 7 at the lower end is lost, it is the same as moving the side weir upward, so that the solidification arc length becomes short at the end of the slab, and the solidification becomes insufficient, so that the molten metal flows from the defective part. It was presumed to have leaked.

According to the present invention, in a continuous casting of a strip slab using a twin-drum type continuous casting machine, the joint between the base member and the lower end of the ceramic plate is prevented from being broken, so that the cooling drum and the side weir can be separated. An object is to prevent molten metal from leaking from a sliding surface.

[0009]

The present inventor has proposed a joint opening m
5 (b), the ceramic plate 7 and the base member 6 are pushed down by the rotational force of the cooling drum 1, and as shown in FIG. 5 (c), the ceramic plate 7 and the base member 6 It is considered that the thermal expansion causes sinking (pushing) into the amorphous refractory 5. In addition, the ceramic plate 7 and the lower end of the base member 6 are damaged by casting over a long period of time.
Of the ceramic plate 7, wear of the ceramic plate 7 progresses, the remaining thickness of the ceramic plate 7 decreases, and the strength decreases. When the drum bites into the drum gap, the drum gap opens momentarily and the drum rolling force drops,
The phenomenon that the slab is insufficiently cooled is called a hot band,
At that time, a large force is also applied in the direction of the side weir). The present invention
It is configured to prevent the ceramic plate and the base member from being pushed down and sink, and also to prevent the ceramic plate and the base member from being lost. The gist of the invention is that a pair of cooling drums that rotate in opposite directions to each other. A side weir slidably contacting both end faces, the side weir being an irregular refractory housed in a metal case, a plurality of upper and lower base members implanted in the irregular refractory, and the base member A plurality of upper and lower ceramic plates implanted in a portion that is in sliding contact with the end surface of the cooling drum, and between the irregular shaped refractory, the base member, and the lower end of the ceramic plate and the metal case. A side dam for a twin-drum continuous casting machine, characterized in that a receiving brick is provided on the side weir. Further, the present invention is characterized in that a chamfered portion is formed at a lower end portion of a lowermost ceramic plate among the plurality of upper and lower ceramic plates.

[0010]

1 and 2 show a first embodiment of the present invention.
It is a diagram illustrating a side weir according to claims 4 to 6,
Metal case 11 formed by bottom plate 11a and side plate 11b
(For example, made of SS41)
(For example, fused SiO ₂ material) is accommodated, and a plurality of base members 13 (for example, high alumina material) are implanted in the irregular refractory.

A groove (not shown) is provided at a portion of the surface of the base member 13 facing the peripheral edge of the cooling drum (1a in FIG. 1), and a plurality of grooves (a total of 17 in the figure) are provided along the groove.
Sheets) of ceramic plates 18 (for example, Si ₃ N ₄ -B
N-AlN) is attached with an adhesive and planted. The ceramic plate 18 makes the sliding with the drum end surface smoother, so that a good seal and the effect of extending the life of the side dam can be obtained.

The rotational force of the cooling drum 9 is provided between the lowermost base member of the upper and lower ceramic plates 18 and the base member 13 and the lower end surface of the ceramic plate and the irregular refractory and the side plate 11b of the metal case. A receiving brick 14 for preventing the ceramic plate 18 and the base member 13 from being pushed down and preventing the ceramic plate 18 and the base member 13 from being damaged is provided in contact with both.

The ceramic plate 18 and the base member 1
In order to sufficiently prevent the joint opening of No. 3, the base member 1
It is desirable to provide a support member 15 for preventing the base member 13 from sinking into the irregular refractory 12 between the back surface of the base 3 and the bottom plate 11a of the metal case. It is desirable that the receiving brick 14 and the support member 15 have a creep strength of a load softening point T2 (2% shrinkage) at 2 kg / cm ² of 1700 ° C. or more as defined in JIS-R-2209. If the load softening point T2 is less than 1700 DEG C., it is not possible to sufficiently prevent the base member from pushing down and sinking. Al ₂ O ₃ is used as a refractory which can sufficiently prevent the base member from pushing down and sinking.
% Is the most suitable.

The support member 15 is disposed at the center of the portion facing the peripheral edge of the cooling drum for each base member 13 so that the balance of the surface pressure can be obtained for each base member 13. ing. It is desirable that the size of the support member 15 be large in order to obtain its strength, but care must be taken so as not to impair the heat insulating effect of the irregular-shaped refractory 12. As shown in FIG. 2, the number of the strut members 15 is one.
Only one base member 13 may be provided at the center of the portion facing the peripheral edge of the cooling drum, or a plurality of base members 13 may be provided at equal intervals from the center. Whatever it is,
It is desirable that the base member 13 obtains a balance of surface pressure.

A gap 16 for compensating for thermal expansion of the base member 13 is provided between the upper surface of the uppermost base member 13a of the upper and lower base members 13 and the irregular refractory 12. In order to sufficiently prevent joint opening of the base member 13, the gap 16 has a thermal expansion of the base member 13.
% Is desirable. A heat insulating material 17 for preventing thermal expansion of the metal case 11 is provided between the bottom plate 11a of the metal case and the refractory material 12, and the heat insulating material 1 is provided.
7 is made by, for example, mixing a binder with a ceramic powder mainly composed of Al ₂ O ₃ and compression-molding the mixture.
It is desirable that the thermal conductivity is 0.5 kcal / m · hr · ° C. or less and the thickness is 2 mm or more.

The side weir 10 has a heater using a SiC heating element or the like embedded in the base member 13 similarly to the well-known one, and the outer surface of the bottom plate 11a of the metal case prevents thermal deformation of the metal case. For this purpose, it is preferable that a stiffener (not shown) with a cooling mechanism is attached, and a Y-shaped anchor (not shown) for fixing an irregular refractory is attached to the inner surface of the bottom plate 11a of the metal case.

Next, an outline of a method for manufacturing the side weir 10 of the present invention will be described with reference to FIGS. With respect to the individual base members 13, the support members 15 are vertically arranged at the center of the bottom plate 11 a of the metal case facing the peripheral edge of the cooling drum or at a position equidistant from the center,
A heat insulator 17 is arranged between the support members 15 and the metal case 1 is provided.
The receiving bricks 14 are arranged at the lower end of 1. In this case, an adhesive is previously applied to each refractory as necessary.

The base member 13 is arranged on the support member 15 and is restrained by a restraining member (not shown). In this state, the gap between the side weir case 11 and the base member 13 is filled with the flowing amorphous refractory 12 by pouring, and after the amorphous refractory is dried, the restraint is released.

The method for forming the gap 16 is as follows.
The expansion allowance during casting is calculated from the thermal expansion coefficient of 3 and a spacer (not shown) having a thickness corresponding to the expansion allowance is inserted before filling the amorphous refractory 12 and removed after drying. Alternatively, the spacer need not be removed if the spacer is flammable.

The ceramic plate 18 is attached to the base member 13.
The ceramic plate 18 is attached to a groove (not shown) provided in a portion of the base member 13 that is in sliding contact with the peripheral edge of the cooling drum by an adhesive or the like, and the surface thereof is polished to finish it flat.

After the refractory is preheated to a predetermined temperature by the heater 19 in which the side weir 10 constructed as described above is embedded in the base member 13, the refractory is brought into contact with both end surfaces of the cooling drum 9 to perform casting. Ceramic plate 18 and base member 1
The ceramic plate 1 is about to be pushed down by the rotating force of the cooling drum (downward arrow in FIG. 5B).
Since the high-strength receiving bricks 14 are arranged between the bottom plate 8 and the base member 13 and the lower end surface of the irregular-shaped refractory 12 and the side plate 11b of the metal case, the joint by the pushing down of the ceramic plate 18 and the base member 13 Opening and loss of the ceramic plate 18 and the base member 13 can be prevented.

As shown in FIG. 5 (b), the base member 13 tends to sink into the irregular refractory 12 due to thermal expansion or the rotational force of the cooling drum. Since the supporting member 15 is supported by the large supporting member 15, joint opening due to sinking into the irregular-shaped refractory 12 can be prevented.

A gap 16 for compensating for thermal expansion of the base member 13 is formed between the upper surface of the uppermost base member and the refractory 12 of the plurality of upper and lower base members 13. Since the gap 16 allows the expansion of the base member 13 due to the heat of the molten metal, the sink 16 can be prevented from sinking into the irregular refractory 12 due to the thermal expansion of the base member 13 as shown in FIG. .

The bottom plate 11a of the metal case and the refractory 1
2, a heat insulating material 17 having a low thermal conductivity is provided, so that the base member 13 and the metal case 1 by the heat of the molten metal are provided.
The joint opening of the base member 13 due to the thermal deformation of 1 can be prevented.

FIG. 3 shows an embodiment according to claims 2 and 3 of the present invention, in which a chamfered portion 20 is formed at the lower end of a ceramic plate 18, and the upper end of a receiving brick 21 is in contact with the back surface of a base member 13 and a metal. It is formed to extend between the cases 11. By forming a chamfer at the lower end of the ceramic plate, it is possible to more effectively prevent the lower end of the ceramic plate from being damaged by the rotational force of the drum, and extend the upper end of the receiving brick between the back of the base member and the bottom plate of the metal case. With this configuration, it is possible to prevent the base member from being pushed down by the rotational force of the cooling drum and sinking or pushing down into the irregular-shaped refractory.

[0026]

EXAMPLE A SUS304 stainless steel was cast using a twin-drum continuous caster provided with the side weirs 10 shown in FIGS. 1 and 2 to continuously cast a thin strip of 1200 mm in width and 4 mm in thickness. did. In the example of the present invention, the molten metal did not leak for 3 hours, and a cast having a good shape could be stably cast. On the other hand, in the conventional example in which the receiving brick is not provided, molten steel often leaks from the sliding surface between the both end surfaces of the cooling drum and the side weir, and this state continues, and the side weir performs its function in a short time. In some cases, it was impossible to continue casting.

[0027]

According to the side weir of the present invention, since a high-strength receiving brick is provided between the irregular-shaped refractory, the base member and the lower end of the ceramic plate and the side plate of the metal case, the receiving brick serves as a cooling drum. The lowering of the base member and the loss of the ceramic plate and the base member due to the rotational force can be prevented, and the chamfered portion is formed at the lower end of the ceramic plate. It can be effectively prevented.

Further, in the side weir according to the present invention, since the upper end of the receiving brick extends between the back surface of the base member and the bottom plate of the metal case, the base member is pushed down by the rotating force of the cooling drum and the base member is pushed down. It is possible to prevent sinking and pushing down into irregular shaped refractories, and since a strong strut member is provided on the back of the base member, the base member is not deformed due to thermal deformation of the base member or rotational force of the cooling drum. A gap is formed between the upper surface of the uppermost base member of the upper and lower base members and the irregular-shaped refractory, and a gap for compensating for thermal expansion of the base member can be prevented while sinking and pushing down into the fixed refractory can be prevented. Therefore, the base member is allowed to thermally expand by the gap, so that thermal deformation can be prevented.

In the side weir according to the present invention, since a heat insulating material having a low thermal conductivity is provided between the bottom plate of the side weir case and the refractory, the heat insulating material allows the base member and the side weir case to be formed. Thermal deformation due to uneven heating can be prevented. As described above, the side weir of the present invention can prevent thermal deformation of the base member and the side weir case, so that joint opening of the base member due to thermal deformation, generation of metal due to joint opening, and molten metal leakage can be prevented.

[Brief description of the drawings]

FIG. 1 is a view of the inside of a side weir of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG. 1;

FIG. 3 is a diagram showing another example of the side weir of the present invention.

FIG. 4 is a perspective view of a twin-drum continuous casting machine.

FIG. 5 is a longitudinal sectional view of a conventional side weir. FIG.
FIG. 5A is a diagram before the joint opening, FIG. 5B is a diagram where the joint opening is caused by the drum rotational force, and FIG. 5C is a diagram where the joint opening is caused by the thermal expansion.

FIG. 6 is a diagram in which a lower end of a ceramic plate is damaged.

[Explanation of symbols]

 1a, 1b cooling drum 2 side dam (conventional) 2a, 2b side dam 3 pool hole 4 metal case 4a bottom plate of case 4b side plate of case 5 irregular shaped refractory 6 base member 7 Ceramic plate 8 Heater 9 Cooling drum 10 Side weir (the present invention) 11 Metal case 11a Case bottom plate 11b Case side plate 12 Irregular refractories 13 Base members 13a to 13d Base member 14 Receiving brick 15 ... pillar member 16 ... gap 17 ... heat insulating material 18 ... ceramic plate 19 ... heater 20 ... chamfered part of ceramic plate 21 ... receiving brick f ... part facing the peripheral part of the cooling drum c ... thin strip slab m ... joint opening part e ... Molten metal

Claims (6)

[Claims] 1. A side weir slidably contacting both end surfaces of a pair of cooling drums rotating in opposite directions, the side weir being an irregular refractory housed in a metal case, and an irregular refractory housed in a metal case. A plurality of upper and lower base members planted in
The base member comprises a plurality of upper and lower ceramic plates implanted in a portion that is in sliding contact with the end surface of the cooling drum, and the irregular shaped refractory, a lower end of the base member and the ceramic plate, the metal case, A side weir for a twin-drum continuous casting machine, wherein a receiving brick is provided between the side weirs. 2. The side dam for a twin-drum continuous casting machine according to claim 1, wherein a chamfered portion is formed at a lower end portion of a lowermost ceramic plate of the plurality of upper and lower ceramic plates. 3. The side dam for a twin-drum continuous casting machine according to claim 1, wherein an upper end of the receiving brick extends between a back surface of the base member and a metal case. 4. The load softening point T2 (2% shrinkage) at 2 kg / cm ² defined by JIS-R-2209 between the back surface of the base member and the bottom plate of the metal case according to claim 1, is 1700. A side dam for a twin-drum continuous casting machine, comprising a column member having a temperature of not less than ° C. 5. The thermal expansion of the upper and lower base members between the upper surface of the uppermost base member and the irregular refractory of the plurality of upper and lower base members according to claim 1.
A side dam for a twin-drum continuous casting machine, wherein a gap that compensates for 00% is formed. 6. The thermal conductivity between the bottom plate of the metal case and the refractory according to claim 1, wherein the thermal conductivity is 0.5 kcal / m.
A side dam for a twin-drum continuous casting machine, wherein a heat insulating material having a temperature of not more than hr · ° C. and a thickness of not less than 2 mm is provided.