JPH0442047Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention is an electric heating method that applies electricity to the molten metal flow pipe itself made of conductive refractory material to prevent metal from adhering to the inside of the flow pipe. Regarding equipment.

[Prior art] As seen in continuous casting equipment, when pouring molten metal from a ladle to a tundish, and from the tundish to a mold, etc., in order to prevent the molten metal from coming into contact with the outside air and oxidizing, a long nozzle or an immersion method is used. Molten metal is injected using a flow pipe such as a nozzle while being isolated from the outside air. However,
The temperature of the molten metal decreases while flowing through the flow pipe, and it tends to adhere to the inner wall of the flow pipe as bare metal.

In order to prevent this metal from adhering, it is possible, for example, to make the flow pipe out of conductive refractories, supply a heating current directly to the flow pipe, and maintain the flow pipe at a high temperature through resistance heating. This was proposed in Japanese Patent Application Laid-open No. 55-64857. In order to uniformly heat the flow tube by this method, it is important to make uniform contact between the flow tube and the current heating electrode. For this purpose, a conductive material such as a graphite sheet is inserted between the flow pipe and the electrode, and the electrode is pressed onto the flow pipe with a pressure of 2 to 20 kg/cm ² to maintain good contact.

[Problem that the invention attempts to solve]

In this case, the crimping source may be a direct method using bolt tightening or a method of indirectly crimping the energized heating electrode to the flow pipe using air, a hydraulic cylinder, or the like.
However, in the method using bolts, it is difficult to remove the electrode during casting, for example, and it is impossible to replace the injection nozzle, which is a flow pipe.

On the other hand, in the cylinder type, it is required to balance the pressing force of the energization heating electrodes that are in contact with both sides of the flow pipe. Further, since pressurizing mechanisms such as cylinders are exposed to high temperatures, they require adiabatic protection. Moreover, in the case of an injection nozzle or the like provided at the bottom of the tundish, the upper part of the nozzle is covered by the nozzle exchange device, so that a power supply section must be provided below the nozzle support hanger of the nozzle exchange device. Therefore, when using this method, the size of the device becomes large, which causes problems in nozzle replacement work, casting work, etc.

Therefore, the present invention supports the pressing mechanism of the energized heating electrode with the hanger of the flow pipe replacement device, thereby making the entire device compact and efficiently heating the portion of the flow pipe where bare metal is observed. With the goal.

[Means for solving problems]

In order to achieve this purpose, the current heating device of the present invention has a connecting rod that penetrates the flow pipe support of the flow pipe exchange device attached to the bottom of the molten metal container, and slides along the connecting rod. One graphite electrode is attached to a freely movable plate via a spring, the other graphite electrode that comes into contact with the flow pipe at a symmetrical position in the circumferential direction is fixed to the tip of the connecting rod, and the movable plate is attached to the movable plate via a spring. It is characterized in that the movable plate is provided with a ball screw that moves back and forth in the direction of the flow pipe.

〔Example〕

Hereinafter, the features of the present invention will be specifically explained using examples with reference to the drawings.

FIG. 1 is a plan view showing an example in which an energizing heating device is attached to a submerged nozzle disposed between a tundish and a mold, and FIG. 2 is a view taken along the line A--A in FIG. 1.

The immersion nozzle 1 is provided between the tundish 2 and the mold 3, and its tip is immersed in the molten metal bath 4 within the mold 3. The immersion nozzle 1 has an upwardly widening upper part, as shown in FIG. 2, and is supported by a nozzle hanger 5 at this part. A pair of graphite electrodes 6a and 6b as electrodes for energization and heating are placed at symmetrical positions in the circumferential direction of this immersion nozzle 1.
is being pressed.

One graphite electrode 6 among the graphite electrodes 6a and 6b
a is connected to a movable plate 8 via a spring 7. This movable plate 8 has holes on both sides through which the connecting rods 9 are inserted, and a ball screw 10 is attached to the plane opposite to the graphite electrode 6a. This ball screw 10 extends through a female threaded portion formed on a fixed plate 11, and has a handle 12 fixed to its tip. Therefore, when the handle 12 is rotated, the movable plate 8 moves forward or backward along the connecting rod 9, and the graphite electrode 6a approaches or moves away from the submerged nozzle 1.

The other graphite electrode 6b is fixed to the tip of a connecting rod 9 that extends through the movable plate 8 and the nozzle hanger 5. Therefore, the handle 12
After the graphite electrode 6a moves in the direction of the immersion nozzle 1 due to the rotation and comes into contact with the immersion nozzle 1, the fixing plate 11 moves in the opposite direction to the immersion nozzle 1 due to the reaction force from the immersion nozzle 1. Further, when the graphite electrode 6a comes into contact with the immersion nozzle 1, the spring 7 is tightened, and the graphite electrodes 6a, 6b are pressed against the immersion nozzle 1 with a uniform pressing force. At this time, the pressing force can be adjusted based on the amount of rotation of the handle 12.

Further, a flexible conductor 13 is attached to each of the graphite electrodes 6a and 6b, and this flexible conductor 1
3 is connected to a power supply (not shown) for electrical heating. Then, electricity is applied to the immersed nozzle 1 from this power source via the flexible conductor 13 and the graphite electrodes 6a, 6b, and the immersed nozzle 1 is heated to a high temperature by resistance heating.

In this way, by installing the energization heating device, the nozzle can be replaced in the same manner as before through the opening 5a provided on the front surface of the nozzle hanger 5 to which the immersion nozzle 1 is attached, and the device can be made more compact. In addition, since heating can be concentrated on the hatched areas in FIG. 2 where metal tends to adhere, the effect of electrical heating is also excellent.

[Effects of the invention] As explained above, in the present invention, by incorporating a pressing device for the energizing heating electrode into the flow pipe replacement device, the overall structure of the device can be made compact, and when replacing the flow pipe, This enables electrical heating of flow pipes without deteriorating workability.
In addition, it is possible to easily carry out electrical heating in areas where base metal tends to adhere. Furthermore, when installing the device, the energizing heating device can be attached by only making minor modifications to the vicinity of the flow pipe attachment hanger.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing an example in which the electrical heating device of the present invention is applied to a continuous casting immersion nozzle, and FIG. 2 is a view taken along the line A--A in FIG. 1.

Claims (1)

[Scope of utility model registration request] A connecting rod is provided by penetrating the flow pipe support of the flow pipe exchange device attached to the bottom of the molten metal container, and one graphite electrode is attached via a spring to a movable plate that can freely slide along the connecting rod. The movable plate is provided with a ball screw that fixes the other graphite electrode that contacts the flow pipe at a symmetrical position in the circumferential direction to the tip of the connection rod, and moves the movable plate back and forth in the direction of the flow pipe. An electrical heating device for molten metal flow pipes, characterized by: