JPH0455771B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for cooling a tundish molten steel heating device after operation, and particularly to a molten steel heating device that can be easily moved after operation and can extend the life of refractory materials. Regarding the cooling method, it is widely used in the field of continuous steel casting.

[Prior art] In continuous casting of steel (hereinafter referred to as continuous casting), molten steel melted in a converter or the like is contained in a ladle and transferred to a continuous casting tandy, where the molten steel is immersed from the bottom to reach the mold. It is injected into the mold via a nozzle or the like. As described above, the temperature of molten steel inevitably decreases as it is transferred from the ladle to the tundish and then to the mold. However, since the casting temperature is extremely important in continuous casting, a tundish equipped with a molten steel heating device is used to heat the molten steel in the tundish if there is a risk that the molten steel in the tundish may drop below the planned casting temperature.

Normally, molten steel heating equipment is shown in Figures 4 and 5.
A channel type low frequency induction heating device as shown in Figures A and B is used. That is, it consists of a heating chamber 4 which is integrated with the tundish body 2 through a flange on the side of the tundish body 2, and the heating chamber 4 communicates with the inside of the tundish body 2 and includes a channel portion 8 which accommodates molten steel 6. Iron core 1
As shown in FIG. A heating coil 12 is wound around one side of the iron core 10, which is attached to surround the channel section 8 and located above and below the center of the channel section 8. A water cooling jacket 16 is provided. Therefore, when low frequency power is applied to the coil 12, the molten steel 6 in the channel section 8 flows through the coil 12.
The secondary coil is configured to be heated by induction.

The heating coil 12 is usually made of copper, but when it is energized, it generates heat and may even rise in temperature and melt, so it is usually hollow and self-cooled by passing water inside. .

On the other hand, since the outer periphery of the coil is in contact with the molten steel 6 through the refractory material 14, if the refractory material 14 is damaged by being corroded by the molten steel 6, there is a risk that the coil 12 and the iron core 10 will be damaged by melting. A cooling device is provided in which a water cooling jacket 16 is provided and cooling water 18 is circulated.

Normally, continuous casting is carried out on a casting bed using a tundish, but when the casting operation is finished, the tundish is moved to a tundish maintenance yard for repair using a tundish car or a crane.

When moving the tundish, a molten steel heating device is installed in the tundish, and conventionally, if the tundish was moved without cooling, the copper heating coil 12 and water cooling jacket 16 would melt due to residual heat, so it is essential to cool the tundish. Ta.

Therefore, conventionally, a place was set up near the casting bed to separate the tundish and molten steel heating equipment, and a long hose was connected to the molten steel heating equipment, and the molten steel heating equipment was moved there while cooling. It was necessary to separate the tank and move it to the maintenance yard again.

Also, as disclosed in Utility Model Application No. 61-46069,
A device has also been proposed in which a cooling water storage tank is installed in a molten steel heating device and the molten steel is moved while being cooled.

These methods require the installation and removal of cooling water-related equipment each time the equipment is moved, which is complicated and hinders work efficiency. On the other hand, when it comes to refractory materials, cooling the molten steel heating device that has regenerated heat after pouring with cooling water is
Rapid cooling caused a heat shock, which caused a short lifespan.

[Problem that the invention seeks to solve]

An object of the present invention is to solve the problems of the prior art as described above, and to provide an effective cooling method after operation of a molten steel heating device, which allows easy movement of the tundish after completion of casting and extends the life of the refractory material. be.

[Means and actions for solving problems]

The gist of the method for cooling the tundish molten steel heating apparatus after operation according to the present invention is as follows.

That is, a channel part fixed to the side of the tundish main body, an iron core that surrounds the channel part in an annular shape through a fireproof material and can be separated into an upper part and a lower part, and a heating coil surrounding the inner columnar part of the iron core. and a water-cooled jacket made of a heat-resistant material that surrounds the heating coil via an insulating material and is in contact with the refractory material. separating the iron core and the heating coil from the channel section; cooling the jacket section of the channel section with gas to a temperature below the nucleate boiling point of water; and supplying liquid to the water cooling jacket after the gas cooling. 1. A method for cooling a tundish molten steel heating apparatus after operation, the method comprising: a step of cooling.

An overview of a tundish molten steel heating apparatus that implements the post-operation cooling method of the present invention will be described. That is, the iron core 10 is connected to the upper iron core 1 as shown in FIG.
It is divided into 0A and lower core 10B,
Normally, the upper core 10A is fixed to the channel portion 8 by a jig 20. However, upper core 1
After removing the jig 20, the 0A and the heating coil 12 can be separated from the channel part 8 and the lower core 10B, which are fixed to the tundish body 2, by a core lifting crane 22, as shown in FIG. can.

The conventional water cooling jacket 16 is made of copper, but in the present invention, the water cooling jacket 16 is made of a non-magnetic heat-resistant alloy. Heat resistance strength is 732℃ x 10
It requires a rapture strength of 20Kg/cm2 ^or more, specifically Inconel 901, Inconel ×
750, Incoloy 826, SUS316L, etc.

Next, a method for cooling the tundish heating apparatus of the present invention having the above characteristics after operation will be explained. When the casting is completed, the tundish is moved to the tundish maintenance yard for repair as described above. In the present invention, first, the upper iron core 10A and the heating coil 12 are removed from the channel section 8 as shown in FIG. To separate. After separation,
The channel part 8 is moved together with the tundish main body 2 without supplying water to the water cooling jacket 16. After separating the upper iron core 10A and the heating coil 12 from the channel section 8, the refractory material and/or jacket section of the channel section recovers heat, so that the refractory material 14 and/or the jacket section 16 of the channel section 8 prevents water from nucleate boiling. The temperature is slowly cooled by gas cooling until the temperature reaches the temperature below the point. Thereafter, after the tundish main body 2 and the channel section 8 arrive at the tundish maintenance yard, water is supplied to the water cooling jacket 16 for water cooling.

In the present invention, since the heating coil 12 is separated from the channel portion 8 immediately after completion of casting, there is no concern that it will be damaged by residual heat. Further, when moving the tundish body 2, no work related to water supply is required, and the operation is simple.

Although the temperature of the water cooling jacket 16 rises due to residual heat during movement, the present invention uses a material with excellent high-temperature strength, so it will not be damaged by heat.

〔Example〕

As shown in Figure 1, the tundish molten steel heating device with a tundish capacity of 10t and 1000KW specifications is divided into an upper core and a lower core, the upper core can be separated from the channel section along with the heating coil, and the water cooling jacket is made of Incoloy 826. did.

Using the tundish molten steel heating apparatus according to the present invention, immediately after the completion of casting, the upper iron core 10A and the heating coil 1 are heated as shown in FIG.
2 is separated from the channel portion 8, and after being moved to a maintenance yard, the jacket 16 is gas-cooled to a temperature below the nucleate boiling point of water, and then the water-cooled jacket 1 is removed from the water-cooled jacket 1.
Water was supplied to 6.

FIG. 3 shows the cooling curve of the jacket in the channel portion of the above embodiment of the present invention. As shown in FIG. 3, in the present invention, the material is gas-cooled to about 200° C., which is the nucleate boiling point of water, and then water-cooled, so that the material is slowly cooled.
Therefore, in the present invention, since the refractory material is not subjected to heat shock due to rapid cooling, the life of the refractory material can be extended compared to the conventional method.

In this embodiment, an example using the jacket part is shown, but it goes without saying that the same effect can be obtained by using a similar cooling method for the refractory material of the channel part.

〔Effect of the invention〕

As is clear from the above embodiments, the present invention consists of separating the tundish molten steel heating device into an upper core and a lower core, using a water cooling jacket made of a material with excellent high-temperature strength, and attaching the upper core and the heating coil to the channel section after casting is completed. After the jacket part of the channel part recuperates, the jacket part of the channel part is cooled with gas to below the nucleate boiling point of water while moving the tundish main body, and then water is supplied to the water cooling jacket to achieve the following effects. I was able to list.

(a) When moving the tandy cylinder after casting, the number of man-hours involved in moving it could be reduced to 1/5 compared to the conventional method in which long hoses are connected and cooled with water.

(b) The life of the refractory material in the channel can be significantly extended compared to the conventional method, which cools with water immediately after casting.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an upper core and a lower core of a tundish molten steel heating apparatus embodying the present invention; FIG. 2 is a perspective view showing separation of the upper core and heating coil from the channel portion in an embodiment of the present invention; FIG. 3 is a diagram showing the temperature change of the channel jacket after the completion of casting in the embodiment of the present invention, FIG. 4 is a partial cross-sectional perspective view of a conventional tundish molten steel heating device, and FIG. FIG. 1 is a plan cross-sectional view and a longitudinal cross-sectional view, respectively, showing a tundish molten steel heating device. 2... Tandate body, 8... Channel part, 10... Iron core, 10A... Upper iron core, 10B
... Lower iron core, 12 ... Heating coil, 14 ...
Fireproof material, 16... Water cooling jacket.

Claims (1)

[Claims] 1. A channel part fixed to the side of the tundish main body, an iron core that surrounds the channel part in an annular shape through a fireproof material and can be separated into an upper part and a lower part, and a heating coil surrounding the inner columnar part of the iron core. , in a cooling method after operation of a tundish molten steel heating apparatus comprising a water cooling jacket made of a heat-resistant material surrounding the heating coil via an insulating material and in contact with the refractory material, the upper iron core is cooled after casting is completed; and separating the heating coil from the channel section, and cooling the jacket section of the channel section with gas to a temperature below the nucleate boiling point of water;
A method for cooling a tundish molten steel heating apparatus after operation, comprising the step of supplying a liquid to a water cooling jacket in the channel section for cooling after the gas cooling.