JPH0614922Y2 - Molten steel weir in twin roll type continuous casting equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Industrial Field of the Invention The present invention relates to a molten steel weir that can be preheated in a twin roll type thin plate continuous casting facility.

2. Description of the Related Art For example, as shown in FIG. 5, a molten metal 2 is supplied from a tundish between mold rolls 1A and 1B arranged in parallel with each other, and a slab 3 is continuously drawn from between the mold rolls 1A and 1B. In the twin roll type continuous casting facility for pulling out, the molten steel receiver 4 that receives the molten metal 2 at the upper part of the mold rolls 1A, 1B is, for example, as shown in the drawing, in a direction orthogonal to the mold roll axes A, B and 1
It is composed of a pair of weir walls 5 that are in sliding contact with the end portions of B. 6
Is the tip of the nose disposed at the mold outlet below the weir wall 5. This weir wall 5 is preheated by a burner before pouring, and the molten metal 2 is contacted and cooled at the time of pouring to prevent formation of shell on the inner surface of the weir wall 5.

However, in the heating by the burner, it is difficult to raise the temperature in the lower part of the weir wall 5 and in the vicinity of the sliding contact portion with the mold rolls 1A and 1B, and the heat is conducted to the mold rolls 1A and 1B to perform predetermined preheating. The temperature may not be reached and shells may be generated on the inner surface of the weir wall 5.

By disposing the weir wall on the mold roll in this way, it is possible to reduce the sliding contact area of the weir wall that slidably contacts the peripheral surface of the mold roll, or a heating element made of graphite on the molten steel contact surface and the mold roll sliding contact surface. The one embedded is JP-A-61-283.
It is disclosed in Japanese Patent No. 444.

However, in the case where the weir wall is arranged on the mold roll, it is difficult to process the curved sliding contact surface, and when the molten steel enters the sliding contact portion, it takes time to repair it. In addition, the one in which the heating element made of graphite is embedded has a slow rise in temperature, and the heating element made of graphite is inflexible and is a straight line combination, making it difficult to embed it in the curved part, and the bent part is screwed. Since the connection is made by fitting the same and the like, the cost of the processing is high.

The present invention solves the above problems, and the cost is low,
It is an object of the present invention to provide a molten steel weir in a twin roll type thin plate continuous casting facility capable of heating and preheating the inner surface of the weir wall uniformly to a temperature at which shell is not formed in a short time.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention provides an inner surface of a weir wall disposed in a direction orthogonal to the axis of a mold roll and in sliding contact with the end surface of the mold roll, from the outer peripheral edge of the mold roll. A step portion is formed at a position spaced apart by a predetermined distance toward the mold roll axial side, and a mold roll sliding contact surface along the outer peripheral edge of the mold roll is formed on the outside, and a mold roll end surface is formed on the mold roll axial side. A mold roll facing surface having a gap is formed, and an electric heater is embedded in the molten metal contact surface and the mold roll facing surface excluding the mold roll sliding contact surface on the inner surface of the dam wall.

Action In the above configuration, by forming the step portion, the area of the slide contact surface of the mold roll can be reduced, and even if heat is radiated from the slide contact surface of the mold roll to the mold roll side, The inner surface of the weir wall including the sliding contact surface of the mold roll can be sufficiently and uniformly preheated by the electric heater provided on the surface facing the mold roll. In addition, the electric heater embedded in the inner surface of the weir wall can raise the temperature of preheating evenly in a short period of time, and can prevent the occurrence of shell due to pouring, which is lower in cost than the heating element made of conventional graphite.

Embodiment An embodiment of the present invention will be described below with reference to FIGS. The same members as those of the conventional example are designated by the same reference numerals, and the description thereof will be omitted.

As shown in FIGS. 1 and 2, a weir wall made of refractory material
On the inner surface of 11, the outer peripheral edge 12A of the mold rolls 1A, 1B,
Predetermined distance from 12B toward axis A and B (5 to 6 mm when mold rolls 1A and 1B have a radius of 600 mm)
A step portion 14 is provided at a position separated from each other, and a gap (D = 5 mm) is formed between the position of the step portion 14 and the end surface 13 of the mold roll on the axial center A and B sides. The width of the sliding contact surface 11a with respect to the mold rolls 1A and 1B corresponds to the predetermined interval.

Electric heaters 15A and 15B are embedded in the inner surface of the weir wall 11 at the molten metal contact surface 11b at the center upper side of the mold roll peripheral edges 12A and 12B, and on the mold roll facing surface 11c on the mold roll side of the step portion 14 respectively. The electric heater 15A, 15B
As shown in FIG. 4, a heater having a diameter of 1.0 to 2.5 mm is inserted into an alumina insulating tube 16 having a diameter of 3 to 4 mm, and the insulating tube 16 faces the molten metal contact surface 11b of the weir wall 11 and the mold roll. Width a formed on the surface 11c and the weir body outer surface 11d
= 5 mm, depth b = 5 mm, and is inserted into a groove 17, and a castable refractory material (high alumina castable) 18 is filled on the groove 17 to form a flush surface. Then, the molten metal contact surface 11
The two electric heaters 15A embedded in b have one end from the top of the inner surface of the weir wall 11 to the outer peripheral edges 12A, 12B of the mold roll
And are buried in a zigzag pattern and symmetrically with respect to the position of the molten metal 19 at the center, and the tips are connected to each other. The two electric heaters 15B embedded in the mold roll facing surface 11c each have one end descending from the upper part of the weir wall outer surface 11d, and make one reciprocation along the step 14 at the mold roll facing surface 11c, and the other end. Is led to the upper part of the weir wall outer surface 11d. Further, lead wires 22 are connected to the ends of the electric heaters 15A and 15B via bolts 20 and heat sinks 21, respectively.

A heat insulating material 23 made of alumina fiber is attached to the mold roll facing surface 11c and the weir wall outer surface 11d to improve the heat insulating effect.

The method of manufacturing the weir wall 11 is such that a groove 17 is formed by machining on the inner surface of the weir wall 11 in which the step portion 14 is formed, and the insulating pipe 16 in which the heater 14 is inserted is fitted along the groove 17. After that, the groove 17 is filled with castable refractory material 18. Then, the weir wall 11 may be assembled, energized, heated and dried.

Next, a method of using this molten steel weir will be described.

Before pouring into the mold rollers 1A and 1B, electricity is supplied from the lead wire 22 to the electric heaters 15A and 15B to preheat the inner surface of the weir wall 11. As shown in FIG. 4, the temperature is measured by a thermocouple 24 installed at a predetermined position at a depth d = 5 mm from the inner surface, and when the temperature reaches 950 ° C., pouring is started. It was confirmed by experiments that the preheating time was extremely short (about 3 minutes) and the inner surface of the weir wall 11 could be uniformly preheated.

Conventionally, the preheating of the weir wall 11 is performed by molten steel (1500 ° C) in the case of molten steel.
Although it has been considered that the above temperature is necessary, even if the temperature 5 mm inside the inner surface of the weir wall 11 is about 950 ° C. (the surface is estimated to be around 1200 ° C.) by the present inventor, the inner surface of the weir wall 11 is estimated. It turned out that no shell was formed. This is because when pouring is started, shells are formed on the surface of the weir wall 11, but the molten steel in the vicinity immediately melts it, and at the same time, the surface temperature of the weir wall 11 rises to the temperature of the molten steel by the molten steel.

Effects of the Invention According to the present invention as described above, the step portion is provided on the inner surface of the weir wall on the mold roll axial center side of the outer periphery of the mold roll to reduce the sliding contact surface between the mold roll end surface and the weir wall. , It is possible to reduce the amount of heat transfer to the mold roll at the time of preheating, and by the electric heaters provided on the melt contact surface and the mold roll facing surface on both sides of the mold roll sliding contact surface,
The inner surface of the weir wall including the slide contact surface of the mold roll can be sufficiently and uniformly preheated, and the temperature of the weir wall in the vicinity of the slide contact surface of the mold roll is not lowered to form a shell on the inner surface.
In addition, since the electric heater is embedded, it can be heated up to the preheating temperature in an extremely short time, and can be bent more freely than the conventional heating element made of graphite, so it can be embedded evenly on the specified surface and the inner surface of the weir can be made uniform. It can be preheated and is low cost.

[Brief description of drawings]

1 to 4 show one embodiment of the present invention, FIG. 1 is a front view showing the inner surface of the weir wall, and FIGS. 2 and 3 are views taken along arrows I-I and II shown in FIG. -II arrow view, FIG. 4 is a sectional view of the electric heater, and FIG. 5 is a schematic perspective view showing a conventional mold roll. 1A, 1B ... Mold roll, 2 ... Molten metal, 3 ... Cast piece, 11 ... Weir wall, 11a ... Sliding contact surface, 11b ... Molten metal contact surface,
11c …… Mold roll facing surface, 12A, 12B …… Mold roll outer peripheral edge, 13 …… Mold roll end surface, 14 …… Step,
15A, 15B: Electric heater, A, B: Mold roll axis, ... Predetermined interval, D: Gap.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yama ▲ High ▼ Hideaki 1-6-14 Edobori, Nishi-ku, Osaka City, Osaka Prefecture Hitachi Shipbuilding Co., Ltd. (72) Mamoru Kurose 1-6 Edobori, Nishi-ku, Osaka City, Osaka Prefecture No. 14 Hitachi Shipbuilding Co., Ltd. (72) Inventor Keihiko Otani 1-6-14 Edobori, Nishi-ku, Osaka City, Osaka Prefecture Hitachi Shipbuilding Co., Ltd. (56) Reference JP 62-124051 (JP, A)

Claims (1)

[Scope of utility model registration request] 1. An inner surface of a weir wall, which is arranged in a direction orthogonal to the axis of the mold roll and is in sliding contact with the end surface of the mold roll,
A step portion is formed at a position spaced from the outer peripheral edge of the mold roll along the axial center side of the mold roll to form a slide contact surface on the outer side of the outer peripheral edge of the mold roll, and at the same time, the axial side of the mold roll is formed. A mold roll facing surface having a gap between the mold roll end surface and a mold roll opposing surface is formed, and an electric heater is embedded in the molten metal contact surface excluding the mold roll sliding contact surface and the mold roll facing surface on the inner surface of the dam wall. A molten steel weir in a twin-roll type thin plate continuous casting facility.