JP3403504B2 - Continuous casting method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used for inserting a rod-like stopper for closing an opening communicating with an immersion nozzle into a tundish at the bottom of a tundish for continuous casting, or for withdrawing the tundish from the tundish. The present invention relates to a method of continuous casting using a lifting and lowering turning device of a stopper used in.

[0002]

2. Description of the Related Art In continuous casting, as shown in FIG. 1, ladles 2a and 2b are attached to both arm ends of a swing tower 1, and molten steel is first poured into the tundish 3 from one ladle 2a. Then, when this molten steel injection is completed, the swing tower 1 is swung to move the next heat ladle 2b onto the tundish 3 to inject molten steel, and thereafter, this operation is repeated, whereby a plurality of heat It is customary to carry out molten steel injection to achieve continuous casting. The molten steel poured into the tundish 3 is continuously cast into a slab through the immersion nozzle 4, the mold 5 and the roller apron 6.

At the start of continuous casting, ladle
Injecting molten steel into the empty tundish 3 from 2a, securing a sufficient amount of molten steel in this tundish, and then injecting molten steel into the mold 5, so-called pooling start, quality control, It is essential to realize stable operation.

There are various methods for starting the pool, and a typical method is the fully closed start method shown in FIG. That is, the fully closed start method is a combination of upper and lower plates 7a and 7b after injecting a predetermined amount of molten steel into the tundish 3 while blowing an inert gas (generally Ar gas) into the opening 8. The sliding plate 7 is moved to make the opening 8 at the bottom of the tundish 3 communicate with the immersion nozzle 4, and the injection of molten steel into the mold 5 is started. The purpose of blowing an inert gas here is
The point is to prevent the molten steel from solidifying during pooling in the opening 8. Further, as a method of blowing the inert gas, it is general to carry out through the refractory of the upper nozzle 20 or the lower plate 7b.

However, according to this method, even if the sliding plate 7 is opened, the opening 8 at the bottom of the tundish 3 is formed.
Since the molten steel solidifies at, the molten steel may not be injected, resulting in poor reliability. When such a trouble occurs, as shown in FIG. 3, oxygen is blown to the coagulating portion 10 via the conduit 9 inserted from above the tundish 3 to the vicinity of the opening 8 to dissolve it, A so-called oxygen opening for opening the opening 8 is performed. However, the oxygen opening is
There is a problem in that inclusions such as Al ₂ O ₃ , FeO, and MnO are generated, which causes deterioration of quality in continuously cast steel.

On the other hand, as a technique for avoiding the above problems,
There is a so-called stopper method using a rod-shaped stopper shown in FIG. That is, this method is tundish 3
This is a method in which the bottom opening 8 is closed by a refractory stopper 11, and the opening 8 is opened and closed by raising and lowering the stopper 11 by an amount that allows molten steel to flow out. This method is more reliable than the above fully closed start method,
Since the refractory cost required for the stopper 11 increases,
It was disadvantageous in terms of running cost.

The stopper method may also be used to prevent the inclusion of slag. That is, after the final ladle of continuous casting is finished, the residual steel in the tundish is cast. At this time, the amount of remaining steel in the tundish decreases, and when the molten steel head goes down, a vortex is generated, which makes it easier to engulf the slag in the upper part of the molten steel and increases the quality deterioration of the continuously cast steel material. , It is avoided by the stopper. This is because it is possible to prevent the generation of a vortex by immersing the stopper. However, even in this case, since the refractory cost required for the stopper is high, it is still disadvantageous in terms of running cost.

[0008]

As described above, in the case where the stopper is used to prevent the start of the pool of water and the entrainment of slag, the refractory cost required for the stopper increases because the stopper is always made of molten steel in the tundish. This is because the immersion causes the refractory to melt and the life to be shortened.

An object of the present invention, the hot water reservoir start and entanglement preventing slag with stopper, without increasing the running cost, also provides a communication <br/> continued casting method for implementing It is in.

[0010]

SUMMARY OF THE INVENTION The present invention is a continuous casting tool .
On the bottom of the dish, slide the
There is an opening that can be opened and closed by
A rod-shaped stopper for closing this is used for raising and lowering and turning.
Fixed to a possible support arm, through this support arm
Support the stopper so that it can move back and forth with respect to the tundish.
The device has a tundish at the end of the stopper.
From the opening to the position that exceeds the upper part of the tundish lid
A lifting mechanism having a moving stroke and the supporting arm
And a swivel mechanism that swivels the stopper and retracts the stopper.
In the method of continuous casting using the elevating and swiveling device for the tundish stopper for continuous casting, at the end of continuous casting, the rod-shaped stopper in the retracted position is swung to move the support arm of the stopper to turn the tundish on the tundish. Move to the position, then lower this stopper into the tundish and immerse it in the molten steel to bring it closer to the tundish opening, then close the opening completely with a sliding plate or open it with the stopper. It is a continuous casting method (first invention) , characterized in that a portion is closed. In addition, the present invention is the end of continuous casting.
In the continuous casting method according to the first aspect of the present invention, which is characterized by an end method, further, at the start of continuous casting, a bar-shaped stopper that closes the opening provided at the bottom of the tundish is lowered to the lowermost position and the opening is opened. The molten steel in the tundish is poured into the tundish in this state, and when the molten steel in the tundish reaches a predetermined weight or the molten steel head reaches a predetermined height, the stopper is closed. It is raised to a position beyond the dish lid, a further supporting arm of the stopper, by pivoting, to start the casting with a this moving from the tundish upward to the retracted position, and, at the end continuous casting, retracted position Move the stopper on to the tundish by pivoting the support arm and then remove the stopper. The casting is finished by lowering it into the dish and immersing it in molten steel, and then approaching the tundish opening and then fully closing the sliding plate or closing the opening with the stopper. It is the continuous casting method (2nd invention) .

[0011]

[Function] It is effective to use a stopper to start slag pooling and prevent entrainment of slag. Start of pooling is required at the start stage of continuous casting, and slag entrainment prevention is required at the end stage of continuous casting. In other words,
The stopper used in these steps is not necessary during steady operation except the start and end stages of continuous casting. Therefore, if the apparatus of the present invention makes it possible to move the tundish forward and backward by raising and lowering the stopper, and further to retreat from the tundish by the turning motion, the stopper is dipped into the molten steel only at the required time. Therefore, the melting loss of the stopper can be minimized, and the life of the stopper refractory can be significantly extended.

[0012]

EXAMPLE A lifting and lowering turning device used in the method of the present invention,
This is shown in FIGS. The stopper 11 is given a reciprocating motion in the vertical direction as shown in FIG. 5 and a rotational motion in a horizontal plane as shown in FIG. 6 via a support arm 12 extending in a substantially horizontal direction. That is, the lifting / lowering device has a support arm having a stopper 11 fixed at its tip.
The base end of 12 is fixed to a swivel head 13, and the swivel head 13 is placed on an elevating table 14.

First, the lifting table 14 that serves as the lifting mechanism of the present invention.
Is a configuration in which a pantograph 17 is interposed between a fixed plate 15 and a movable plate 16, and the pantograph 17 is operated by a hydraulic cylinder or an electric motor, and as shown in FIGS. 5 (a) and 5 (b), The moving plate 16 is reciprocated in the vertical direction with respect to 15. By this reciprocal movement, the stopper 11 is lifted and lowered through the swivel head 13 and the support arm 12 placed on the fixed plate 15. Here, the stroke of the reciprocating movement of the movable plate 16 with respect to the fixed plate 15 is determined by the end of the stopper 11 from the opening 8 of the tundish 3 to the lid 3a of the tundish 3.
It is important to set the range to move to a position that exceeds the upper part.

The elevating mechanism is not limited to the illustrated example, but the moving plate 16 may be directly moved up and down by a hydraulic cylinder or the like.

Next, the swivel head which is responsible for the swivel mechanism of the present invention.
The unit 13 is rotatably installed on the moving plate 16 of the elevating table 14, and can be swung within a range of, for example, 65 ° by a hydraulic cylinder or an electric motor, as shown in FIG. Further, reference numeral 18 is a balance weight provided in the rear of the swivel head 13 for balancing with respect to the weight of the stopper.

The turning mechanism is not limited to the illustrated example, but a turning device may be placed below the fixed plate to turn the entire lifting mechanism.

Further, in the illustrated example, the lifting table 14 is mounted on the tundish car 19 and moved together with the tundish car 19. However, for example, the lifting table 14 should be fixed on the casting floor before use. Is also possible.

As shown in FIG. 5 (a), the elevating and swiveling device having the above-described structure is provided as shown in FIG.
The stopper 11 is lowered to the lowest position to close the opening 8, and in this state, the injection of molten steel from the ladle into the tundish 3 is started. Next, when the molten steel in the tundish 3 reaches a predetermined weight or the molten steel head reaches a predetermined height, the stopper 11 is raised to a position over the lid 3a of the tundish 3 as shown in FIG. 5 (b). And further in FIG.
As shown in FIG. 5, the stopper 11 is retracted from above the tundish 3 by turning the support arm 12, and the stopper 11 is made to stand by at a predetermined position. If the stopper interferes with the swing tower or ladle, in the same way as above, during the ladle replacement after the first heat casting is completed,
Evacuate 11 from Tundish 3.

In order to prevent the slag from being caught at the end of continuous casting, the stopper 11 at the standby position is inserted into the tundish 3 in the reverse order of the above procedure, and the stopper 11 is dipped in the molten steel and the stopper 11 is used. Tundish opening 8
You can bring it closer to. At the end of casting, the sliding plate 7 may be fully closed or the opening 8 may be closed by the stopper 11.

[0020]

According to the present invention , since it is not necessary to immerse the stopper in the molten steel except when the stopper is needed, the running cost, which has hitherto been an obstacle to the implementation of the stopper method, can be kept low. It is possible to prevent the start of the hot water pool and the entrainment of slag by the stopper method. By the way, by retracting the topper out of the tundish by the method according to the present invention, it was possible to extend the life of the stopper refractory material 10 times as compared with the conventional one.

[Brief description of drawings]

FIG. 1 is a schematic view showing a process of continuous casting.

FIG. 2 is a schematic diagram showing a fully closed start method of continuous casting.

FIG. 3 is a schematic diagram showing oxygen openings.

FIG. 4 is a schematic diagram showing the start of a molten pool for continuous casting.

FIG. 5 is a schematic view showing how the stopper is lifted and lowered by the lifting and swiveling device of the present invention.

FIG. 6 is a schematic view showing the turning of the stopper by the lifting and turning device of the present invention.

[Explanation of symbols]

1 swing tower 2a ladle 2b ladle 3 tundish 3a lid 4 immersion nozzle 5 molds 6 roller apron 7 sliding plate 7a upper plate 7b lower plate 8 openings 9 conduits 10 Coagulation part 11 Stopper 12 Support arm 13 swivel head 14 Lift 15 Fixed plate 16 moving plate 17 Pantograph 18 balance weight 19 tundish car 20 upper nozzle

─────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-5-200504 (JP, A) JP-A-63-2542 (JP, A) JP-A-2-142650 (JP, A) JP-A-6- 170502 (JP, A) (58) Fields surveyed (Int.Cl. ⁷ , DB name) B22D 11/10 310 B22D 41/20

Claims (2)

(57) [Claims] 1. A bottom part of a tundish for continuous casting,
Has an opening that can be opened and closed by a riding plate
However, this opening also has a rod-like shape to close it.
The stopper is fixed to a support arm that can be raised and lowered and swiveled.
The stopper is tundish via this support arm.
Device that supports the unit so that it can move back and forth.
The end of the par is tundish from the tundish opening
Has a stroke to move to a position that exceeds the top of the lid
Lifting mechanism and the above-mentioned support arm are rotated to make a stopper.
Continuous casting using a tundish stopper lifting / lowering swivel device for continuous casting equipped with a swivel mechanism for retracting
In the method, at the end of continuous casting, the rod-shaped stopper in the retracted position is moved to a position on the tundish by pivoting the support arm of the stopper, and then this stopper is lowered into the tundish. A continuous casting method, which comprises immersing the steel plate in molten steel to bring it close to the tundish opening, and then completely closing the opening with a sliding plate or closing the opening with the stopper. 2. The bottom of the tundish for continuous casting is provided with a spout.
Has an opening that can be opened and closed by a riding plate
However, this opening also has a rod-like shape to close it.
The stopper is fixed to a support arm that can be raised and lowered and swiveled.
The stopper is tundish via this support arm.
Device that supports the unit so that it can move back and forth.
The end of the par is tundish from the tundish opening
Has a stroke to move to a position that exceeds the top of the lid
Lifting mechanism and the above-mentioned support arm are rotated to make a stopper.
In the method of continuous casting using the lifting and turning device of the tundish stopper for continuous casting, which has a turning mechanism for retracting, a rod-shaped stopper that closes the opening provided at the bottom of the tundish at the start of continuous casting , Lower it to the lowest position to close the opening, start pouring molten steel from the ladle into the tundish in this state, and then put the molten steel in the tundish at the specified weight or the molten steel head at the specified height. they become, the stopper was raised to a position beyond the lid of the tundish, a further supporting arm of the stopper, by pivoting, to start the casting with a this moving from the tundish upward to the retracted position, When the continuous casting is completed, the stopper in the retracted position is rotated to rotate the support arm. The stopper is lowered into the tundish and immersed in the molten steel, and the sliding plate is fully closed after approaching the tundish opening, or the opening is closed with the stopper. The continuous casting method is characterized in that the casting is thereby completed.