JPH0255142B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a tundish for continuous casting, and particularly to a tundish having a function of heating molten steel.

[Conventional technology]

In continuous casting, molten steel produced in a converter is stored in a ladle and transported to the upper part of the tundish, and is passed through a long nozzle removably attached to the bottom of the ladle by opening and closing a sliding nozzle. It is then transferred to a tundish, and then poured into a mold through a submerged nozzle provided at the bottom of the tundish for continuous casting. By the way, in continuous casting, the temperature of molten steel in the tundish has a very large effect on the operation and the quality of the manufactured slab. For example, if the temperature of the molten steel in the tundish is too low, slag entrapment and unevenness will occur frequently on the surface of the slab, and non-metallic inclusions will increase, making it difficult to obtain a normal slab. , the tandate nozzle (long nozzle) becomes easily clogged, making stable operation difficult. On the other hand, if the molten steel temperature is too high, the columnar crystals in the solidified structure of the slab will develop significantly, which will cause internal cracks, and center deflection will become noticeable as well. Cracks are likely to occur, resulting in operational problems such as breakouts.

Therefore, it is extremely important to maintain the molten steel temperature in the tundish within an appropriate range in order to stabilize continuous casting operations and improve slab quality.

A tundish having a heating function for molten steel has been disclosed as a measure to eliminate fluctuations in the temperature of molten steel in the tundish and maintain a substantially constant appropriate temperature during continuous casting operations. For example, in JP-A-54-163730,
A method is disclosed in which a channel-type induction heating device is installed at the bottom or side of a tundish, and the heating section and the tundish main body are detachably attached to heat molten steel to an appropriate temperature. However, in normal continuous casting operations, tandy flux is poured into the tundish to prevent oxidation of the molten steel, and since converter slag, etc. flowing out from the ladle is floating, a fairly thick slag layer is formed. intervenes.

If such slag flows into the mold, it will deteriorate the quality of the slab, so even when the bricks in the tundish are replaced, a small amount of molten steel is left in the tundish. However, in the above-mentioned conventional tundish with induction heating function, the bottom of the tundish and the bottom of the channel part are on almost the same level, so the remaining molten steel and slag solidify, making it difficult to attach and detach the tundish body and the channel of the heating part. Therefore, there was a drawback that the refractory material of the tundish body and the channel of the heating section had to be destroyed.

Further, Japanese Utility Model Application No. 50-106420 also discloses a continuous casting tundish having a detachable heating section.

This invention is based on ``a tundish for continuous casting characterized by having a passageway that communicates with and circulates the molten steel in the tundish that projects outside the tundish and is integrally formed therein, and that a low-frequency heating device is provided surrounding this passageway. '', as is clear from the filing date, this invention is an early continuous casting tundish, and its purpose is to compensate for the temperature drop of molten steel in the tundish to cool down the nozzle at the end of casting. The objective is to prevent this and further control the temperature of the molten metal arbitrarily.

However, this device also suffers from the drawback that the present invention seeks to improve, namely, because the bottom surface of the tundish and the bottom of the groove are almost at the same level, the remaining molten metal and slag solidify, and during repair, the tundish body and the heating section are The disadvantage is that it is impossible to separate the refractory from the groove, and the refractory material must be destroyed.

[Problem to be solved by the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide an effective continuous casting tundish which eliminates the drawbacks of the conventional continuous casting tundish device having a molten steel heating function and enables smooth repair work when repairing the tundish.

[Means and effects for solving the problems] The gist of the present invention is as follows.
That is, there is a tundish main body that contains a steel shell surrounding the outside and a refractory material lined inside the steel shell, which accommodates molten steel, and a fireproof material that can be detachably attached to the outside of the lower side wall of the tundish main body through a connecting part. a molten steel heating section having a groove integrally formed of a material and a heating device that heats the molten steel through the groove;
A tundish for continuous casting, characterized in that the groove is horizontal and a step is provided so that the bottom surface of the horizontal groove is 100 to 200 mm higher than the bottom surface of the tundish main body. This is a tandate for use.

Embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a plan view showing a tundish for continuous casting according to the present invention, and FIG. 2 is a cross-sectional view taken along the - line in FIG. 1. As shown in FIGS. 1 and 2, the continuous casting tundish according to the present invention consists of a tundish main body 2 and a molten steel heating section 4, which are integrally constructed so as to be detachably attached via a connecting section 18.
The tundish body 2 is surrounded by an iron shell 6 and the inside thereof is lined with a refractory material 8, like a conventional tundish. A horizontal groove portion 12 is provided below the side wall 10 in the longitudinal direction of the tundish body 2, and this portion is also surrounded by an iron shell 6 on the outer periphery and lined inside with a fireproof material 8, and is integrated with the tundish body 2. has been done. A molten steel heating device is provided in the horizontal groove 12, and in this embodiment, a coil 14 and a coil 14 surrounding the horizontal groove 12 are provided.
An iron core 16 is provided across the magnetic field generated by the horizontal groove 12, and an electromagnetic induction heating device for induction heating the molten steel stored in the horizontal groove 12 is provided. This heating means is not limited to induction heating, and other methods are also possible.

The thus heated molten steel 20 is injected into a mold provided below through the sliding nozzle 22 and the immersion nozzle 24 at the bottom of the tundish 2.

By the way, in the conventional tundish body 2 having a heating function, the bottom surface of the tundish main body 2 and the bottom surface of the horizontal groove part 12 of the molten steel heating section 4 are on the same level. However, in the present invention, as shown in FIG. It is characterized by having a step of height h. The appropriate height h of the step is 100 to 200 mm based on the amount of remaining molten steel.

Since there is a step as shown above, when repairing the tundish body 2 or the molten steel heating section 4,
Even if a small amount of molten steel or slag is left inside the tundish body 2, the molten steel or slag remains on the bottom surface of the tundish body 2 and does not flow into the horizontal groove 12, so that the connection part 18 can be easily disconnected. Therefore, it is possible to connect to a new tundish main body 2 without repairing the molten steel heating section 4. In addition, the tundish body 2 and the horizontal groove part 12
The connection can be easily attached and detached by attaching and detaching bolts and nuts.

〔Effect of the invention〕

As is clear from the above examples, the continuous casting tundish having a molten steel heating function according to the present invention has the following features:
Since a step of 100 to 200 mm was provided between the bottom surfaces of the horizontal groove section 12 connecting the tundish body 2 and the molten steel heating section 4, the following effects could be achieved.

(a) Since the tundish body 2 and the molten steel heating section 4 can be easily attached and detached via the connecting part 18, the repair period of the tundish body 2 can be significantly shortened, and the life of the molten steel heating section can be significantly extended. I was able to do that.

(b) As a result of the improved workability of tundish trough repair, the amount of molten steel left inside the tundish trough can be slightly larger than before when repairing, which completely prevents slag from flowing into the mold and improves slab quality. It became possible.

Although the present invention has been described with respect to a tundish having a heating function, the technical idea of the present invention can also be applied to the case where a heating device is provided to the side wall of the ladle.

[Brief explanation of drawings]

FIG. 1 is a plan view showing a tundish for continuous casting according to the present invention, and FIG. 2 is a sectional view taken along the - line in FIG. 1. 2... Tandate body, 4... Molten steel heating section, 6... Steel shell, 8... Fireproof material, 10... Side wall,
12... Horizontal groove portion, 14... Coil, 16... Iron core, 18... Connection portion, 20... Molten steel, 22... Sliding nozzle, 24... Immersing nozzle.

Claims (1)

[Claims] 1. A tundish body that accommodates molten steel and has an iron shell surrounding the outside and a refractory material lined inside the outer sheath, and a refractory material that can be freely attached and detached to the outside of the lower side wall of the tundish body through a connecting part. A tundish for continuous casting comprising a molten steel heating section having a groove integrally formed with a groove and a heating device for heating the molten steel through the groove, wherein the groove is horizontal and the horizontal groove is 1. A tundish for continuous casting, characterized in that a step is provided on the bottom surface of the tundish so that the bottom surface is 100 to 200 mm higher than the bottom surface of the tundish body.