JP3510053B2 - Tundish for hot waste and hot waste disposal method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tundish and a hot slag removal method, which are used for hot slag for multi-strands in a step of continuously casting a molten metal.

[0002]

2. Description of the Related Art Tundish is being hot reused for the purpose of cost reduction in continuous casting. Hot reuse of tundish means discharging the remaining molten metal / slag of the tundish in a molten state at the end of casting, and replacing / maintaining the refractory for injection such as the tundish stopper and injection nozzle if necessary. However, it is a method of continuously using the same tundish for the next casting, and compared with the conventional method of temporarily cooling and removing the residual molten metal and slag in the tundish, the maintenance time of the tundish is significantly longer. Not only can it be shortened, but refractory costs and tundish preheating gas can be reduced.

The most important technical point in hot reuse of tundish is how to completely discharge the residual molten metal and slag in the tundish. It is known that the residual molten metal / slag remaining in the dish may adversely affect the quality during the next casting.

As a conventional tundish premised on hot slag, there is a molten steel pouring flow dropping region which is poured from a ladle through a long nozzle as described in JP-A-4-351251. , A slag / metal inclusion inclusion floating area having an injection nozzle is provided downstream of the molten steel injection flow drop area, and a slag weir to prevent slag from flowing out of the injection flow drop area to the floating area is provided in both areas. It is installed in a partition and the recess is provided in the injection flow drop area to narrow the area where the residual molten metal and slag are present in the tundish, and the shape of the tank is advantageous for hot drainage. Dishes are disclosed.

[0005]

However, in the case of a tundish for hot slag in a continuous casting facility for multi-strands having three or more strands on which the present invention is based,
Providing a weir or forming a recess in the bottom as in the conventional tundish not only makes the refractory of the weir and the structure of the tundish complicated, but also increases the cost, and especially when the tundish has three or more strands. In the case of a dish, the weir becomes very large and the shape of the bottom of the tundish becomes more complicated, which is not suitable for practical operation.

In view of the above problems, an object of the present invention is to provide a tundish and a tundish hot waste that can be applied to hot reuse at low cost even in a continuous casting facility for multi-strands having three or more strands. It provides a method.

[0007]

SUMMARY OF THE INVENTION The present invention has the following structures. In a multi-strand tundish with 3 or more strands, the residual molten metal from the tundish
The slag hole for discharging the slag is arranged near the vertical bisector of the straight line connecting the injection holes corresponding to both strands of the injection hole for injecting the molten metal into the mold, drop position (hereinafter, referred to as hot water dropping unit), and the Haikasuana, the above each range, respectively 800mm between three positions of each injection hole, said end Stra
The axis of rotation parallel to the straight line connecting the inlet holes of the
Tundish for hot slag, which has the function of tilting the dish. Furthermore, in the above tundish, the shape of the tundish viewed from above is
Side wall of the tundish facing from the injection hole side to the slag hole side
The width of the tundish gradually narrows toward the slag hole side.
It is formed so as to be round and has the tundish side wall.
An angle (α) formed with a rotation axis for tilting the tundish is 10 ° or more , and hot slag is provided.
For tundish. Further, by using the tundish above reporting, when discharging the residual molten slag from the tundish, the Haikasuana tilting the tundish as lower than the normal position position by the ability to tilt the tundish, The hot slag method is characterized by discharging the residual molten metal and slag from the slag hole.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is shown in FIG.
As shown in the examples, in a hot slag tundish 1, a straight line L is formed by connecting a slag hole 2 for discharging a residual molten metal and slag from a tundish to an injection hole 3 corresponding to both strands. By arranging in the vicinity of the vertical bisector, the residual molten metal and slag in the entire tundish can be quickly discharged in the shortest distance. Also,
The distance l ₁ between the molten metal dropping part 4, the slag hole 2 and each injection hole 3,
l ₂ and l ₃ are each a predetermined distance or more, preferably 800
By ensuring a diameter of at least mm, silica sand etc. packed in the slag hole will be washed away by the injection flow during casting, and metal will adhere to the slag hole, blocking the slag hole partially or entirely. In addition, it prevents the slag after casting from failing to function properly, and also causes local damage to the refractory of the pouring system due to the pouring flow from the pouring part and the injection hole for slag and inclusions caught in the pouring part It is possible to prevent the intrusion of the molten metal and the residual molten metal / slag to the vicinity of the injection hole when the slag is discharged.

Further, as shown in FIG. 1 (b), the tundish 1 can be tilted, and at the same time, the residual molten metal and slag can be easily collected in the slag hole. It is more effective in terms of improving the slag removal property by making 1a a structure in which the slag is inclined toward the slag hole by a predetermined angle α or more with respect to the rotation axis A that tilts the tundish. This angle α needs to be at least 10 °. Here, in the unlikely event that the drainage hole does not function for some reason, it is advisable to provide a drainage gutter (which may also be used as an emergency gutter) on the tundish side wall on the side of the drainage hole.

FIG. 2 shows the relationship between the distance from the molten metal falling part of the slag hole and the flushing agent for the silica sand packed in the slag hole, confirmed by a water model test. The method is the tundish (150 tons, 4 strands) shown in the following examples.
A half-scale model is created and simulated fillings (granular type and clay-based material) are used to measure 2000
A pseudo injection of an amount corresponding to t was performed, and the amount of the pseudo filling to be washed out was measured , indexed and examined . From the experimental results, if the distance between the slag hole and the molten metal drop is 800 mm or more
It was confirmed that the rinsing index was 20 or less, that is, almost no rinsing of silica sand was completed, and the slag after the completion of casting could be normally performed.

Similarly, FIG. 3 also confirms the relationship between the distance between the molten metal drop portion and its nearest injection hole and the inflow amount of slag by a water model. The method uses the above-mentioned water model tundish, mixes pseudo inclusions (polyethylenes) in water and injects it into the tundish, and makes pseudo slag (liquid paraffins) exist in the tundish, Perform casting, measure the amount of pseudo inclusions or pseudo slag flowing out of the injection hole, and measure it.
It was indexed and examined . From the experimental results, if the distance between the molten metal drop part and its closest injection hole is 800 mm or more, slag and
It was confirmed that the existence levitation index was 80 or more, that is, inclusions and slag almost floated before reaching the injection hole and had almost no influence on the quality .

[0012]

EXAMPLES The present invention was applied to an actual tundish under the following conditions.・ Heat size: 230ton / ch ・ Tundish capacity: 15ton ・ Number of strands: 4 strands ・ Distance between molten metal drop and slag hole l ₃ ； 1100mm ・ Distance between molten metal drop and nearest injection hole l ₂ ； 1100mm・ Angle α of the tundish side wall toward the slag hole with respect to the tilt axis α: 15 ° An average of 10 ch / cast and 5 casts for the tundish with the above specifications
Applied to. As a result, the residual molten metal and slag could be discharged from the tundish without any problem by opening the slag hole within 5 minutes after the completion of casting. After the discharge, the area around the slag hole was observed, but no metal adhesion was observed near the slag hole,
The padding that had been filled in the slag hole (using silica sand at this time)
It was confirmed that was not washed away by the injection flow. In addition, a quality survey was conducted on the cast slabs when the tundish was reused, but no harmful inclusions due to the entrained slag were found.

[0013]

According to the present invention, even in a multi-strand tundish having three or more strands, the tundish can be applied to the next casting smoothly at a low refractory cost and effectively after the casting is completed. In addition, hot reuse was possible without impairing the quality of the cast slab.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of the present invention.

FIG. 2 is a view showing a relationship between a distance from a molten metal drop portion of a slag hole and a silica sand washing-off index.

FIG. 3 is a diagram showing the relationship between the slag / inclusion levitation index and the distance from the molten metal spilling part and its nearest injection hole.

[Explanation of symbols]

1 tundish 2 slag hole 3 injection holes 4 Hot water falling part

─────────────────────────────────────────────────── --- Continuation of the front page (56) References JP-A-6-304720 (JP, A) JP-A-3-210948 (JP, A) JP-A-6-126393 (JP, A) JP-A-6- 7903 (JP, A) JP 5-42348 (JP, A) Actual flat 3-120947 (JP, U) Actual flat 4-75651 (JP, U) Actual flat 2-118647 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) B22D 11/10 310 B22D 11/00 B22D 43/00

Claims (3)

(57) [Claims] 1. In a multi-strand tundish having three or more strands, a slag hole for discharging a residual molten metal / slag from the tundish is provided at both end strands of a pouring hole for pouring the molten metal into a mold. Arranged in the vicinity of the vertical bisector of the straight line connecting the corresponding pouring holes, and between the positions of the molten metal dropping position from the pan (hereinafter referred to as the pouring part), the slag hole, and the pouring holes. each distance and each 800mm or more, the two ends Stra
The axis of rotation parallel to the straight line connecting the inlet holes of the
Tundish for hot slag, which has the function of tilting the dish. 2. The shape of the tundish viewed in plan is
Tundish facing from the injection hole side to the slag hole side
The width of the tundish gradually increases from the side wall toward the slag hole side.
Is formed so as to narrow, and, the tundish sidewall and the angle between the rotary shaft for tilting the tundish (alpha) is hot according to claim 1, wherein a is 10 ° or more Tundish for waste . 3. Using the tundish 請 Motomeko 1 or 2, wherein, when discharging the residual molten slag from the tundish is inclined tundish the ability to tilt the tundish Haikasuana Is a position lower than the normal position, and the residual molten metal / slag is discharged from the slag hole.