JP2856075B2 - Method of using tundish for continuous casting machine, remodeling method and casting floor equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of using a tundish in a continuous casting machine for continuously casting slabs, billets and the like by casting molten steel from a ladle into a mold via a tundish, and to a method of using an existing continuous casting machine. The present invention relates to a remodeling method and a casting floor facility of a continuous casting machine.

[0002]

2. Description of the Related Art In a continuous casting method, as shown in FIG. 4, molten steel produced in a steelmaking furnace such as a converter is put into a ladle 1 and transported to a position above the continuous casting machine. Then ladle 1
With a ladle turret 2 or ladle car,
The molten steel in the ladle is poured into the mold 4 via the tundish 3. The tundish 3 has a tundish injection pipe 5 (a molten steel flow between the ladle and the tundish at the top).
a large-diameter pipe for gas sealing), equipped with a sliding nozzle device 6 and a submerged nozzle 7 at the lower part to temporarily store molten steel from a ladle and to rectify the flow of molten steel to a constant level.
It is an intermediate container that controls the injection flow rate and feeds it into the mold, and also serves as a distribution container in a multi-strand that simultaneously manufactures a plurality of slabs.

[0003] In such a continuous casting machine, in the small-lot production in accordance with the gradual and diversification of user needs for steel in recent years, when the continuous casting of one trial is completed, the tundish used for casting is removed from the tundish maintenance yard. Carrying the necessary maintenance and replacing it with a new tundish that has been kept on standby during this maintenance, the next continuous casting is continued.

That is, FIG. 3 is a schematic plan view of a casting floor facility in a conventional existing two-strand continuous casting machine, and shows a continuous casting machine center line CL on a casting floor 10.
Tundish preheating devices 11-1 and 11-2 are installed at two places b and c on the left and right, respectively, and two tundish cars 12-1 and 12-2 are placed above the mold at the casting position a and the preheating. The tundish maintenance equipment 13 is disposed so as to be able to reciprocate between the standby positions b and c, and is located in a tundish maintenance yard d lower than the casting floor 10.
The tundish is exchanged and maintained as follows (see FIG. 5).

(1) Two tundish cars 12-1,
12-2, pre-maintained tundish 3-1
3-2 is mounted, and continuous casting is performed with one No. 1 tundish 3-1 of the two right and left units, and the other No. 2 tundish 3-2 is heated with a preheating burner of a tundish preheating device 11-2. Preheat and wait.

(2) When the continuous casting of one trial is completed, the used No. 1 tundish 3-1 is placed in the preheating standby position b.
From here, lifted and moved by crane 14 from here,
It is transported to the tundish maintenance yard d by the rebuilding trolley 15, and the tundish maintenance equipment 13 performs warm or cold maintenance.

The cold maintenance work includes a tundish 3
Disposal of residual steel and residue, removal of immersion nozzle 7, removal of tundish injection pipe 5 and tundish lid 8, water cooling of tundish 3, removal of metal in tundish 3, cassette plate of sliding nozzle device 6 The nozzle replacement, the refractory spraying repair of the tundish 3, the installation of the tundish injection pipe 5 and the tundish lid 8, the installation of the immersion nozzle 7, and the like are included.

(3) During this maintenance, the No. 2 tundish 3-2 waiting at the preheating standby position c is moved to the casting position a by the tundish car 12-2, and the next continuous casting is performed. Continue the operation. Further, on the tundish car 12-1 vacant at the preheating standby position b, bring the No. 3 tundish 3-3 already completed in the maintenance yard and perform preheating for the next casting, After completion of preheating, it is kept on standby.

As described above, five to six tundishes 3 are used in order, and after use, the tundish maintenance yard d is used.
After 5 or 6 tries are completed (about 20 hours), the first tundish 3-1
Is trying to cast.

However, in such a conventional method of using a tundish, the tundish is frequently changed every trial and the tundish is maintained in a warm or cold state in order to cope with recent small lot production. A large number of items must be prepared.The life of refractories in the tundish is reduced due to wear of refractories due to maintenance and refractory fatigue due to temperature changes.
There are problems such as increased heat loss due to repeated cooling and heating of the tundish, and the need for dedicated staff for tundish maintenance.

As a means for solving such a problem,
Japanese Patent Publication No. 5-26589 proposes a continuous casting method in which a tundish after completion of casting is hot-maintained and casting is performed with the tundish that has been hot-maintained.

[0012] In this continuous casting method, in the hot state immediately after the end of casting, the residue and residual steel in the tundish is discharged, the residual steel is treated such as cleaning the inner surface and slag is removed, and the sliding nozzle and the immersion nozzle are replaced. In accordance with the above, maintenance such as inner surface repair of spraying refractories locally on the inner surface of the tundish is performed, and the tundish thus hot maintained is set on a mold to perform the next casting. Furthermore, at the start of casting, the tundish into which the molten steel has been poured is moved to the side of the mold, where the molten steel is heated non-oxidatively by a plasma torch or the like, and stirred with a stirrer, etc. Separation and floating of slag and oxide inside.

[0013]

However, when the conventional tundish hot maintenance method as described above is applied to an actual continuous casting machine, the following problems occur.

In a multi-strand machine having two or more strands, the shape of the tundish is large and complicated, and it takes time (30 to 50 minutes) for hot maintenance of the tundish (including waste) (30 to 50 minutes). 6, the tundish hot maintenance equipment 100 is required on both sides of the center line CL of the continuous casting machine as shown in FIG.
Significant initial cost is required.

Further, the number of tundish is substantially 3
However, 4 or 5 groups are required for two or more strands. As described above, the shape of the tundish is large, and the cost of the tundish is high for both initial and running. Furthermore, the size of the tundish car on which the tundish is mounted is further increased, which in turn increases the cost of the entire continuous casting facility.

[0016] Tundish hot maintenance equipment 100 must be installed on both sides and 4 to 5 tundishes must be arranged. The casting floor 10 of the continuous casting machine becomes extremely wide, and the existing continuous casting is performed. Equipment cannot be physically employed.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems. It is an object of the present invention to provide a continuous casting method in which a tundish is continuously hot-maintained and used continuously. An object of the present invention is to provide a tundish use method, a remodeling method, and a cast floor facility of a continuous casting machine that can be compact and inexpensive and can perform hot maintenance of a tundish even on an existing cast floor. .

[0018]

A method for using a tundish of a continuous casting machine according to the present invention is to cast molten steel in a ladle through a tundish into a mold, and after completion of the casting,
Only the slag remaining in the tundish used for the casting, or the slag and steel are hot-discharged, and the tundish is hot-maintained without substantially cooling. In the continuous casting method in which the following casting is carried out using a continuous casting machine, as shown in FIG. A maintenance facility 20 is provided, and a tundish preheating device 11 is provided on the other side.
After the casting, the first tundish 3-1 after the casting is processed by the tundish hot waste and hot maintenance equipment 20 to treat the residue or the remaining steel and replace the tundish consumable parts (replacement of the immersion nozzle, The following casting is performed, and the first tundish 3-1 is replaced.
Is repeated a plurality of times, the first tundish 3-1 is repaired with refractory by the tundish hot waste / hot maintenance equipment 20 (replacement of the refractory of the cassette of the slide-dig nozzle device, inner surface of the tundish, etc.). Spraying / spray repair) and the tundish preheating device 11
The casting is continued with the second tundish 3-2 that has been preheated and kept on standby.

A method for converting a continuous casting machine according to the present invention is as follows.
In the casting floor equipment of the existing continuous casting machine shown in FIG. 3, the tundish preheating devices 11-1 and 11-2 and the tundish cars 12-1 and 12 are disposed on both sides of the continuous casting machine center line CL. -1, the tundish preheating device 11-1 on one side is removed, the tundish hot waste / hot maintenance equipment 20 is additionally installed, and the tundish preheating device 11-2 ( 11) and the tundish car 12-2 are used.

In the casting floor equipment of the continuous casting machine according to the present invention, the tundish preheating device 11 and the preheating tundish car 12-2 are arranged on one side of the center line CL of the continuous casting machine, and the other. Is provided with a casting-only tundish car 12-1 and a tundish hot waste / hot maintenance facility 20.

[0021]

In the above construction, the first tundish 3-1 mounted on the tundish car 12-1 dedicated to casting disposed on the side where the hot waste / hot maintenance equipment is located, for example, five trials are used. In the meantime, the tundish is not repaired, only the injection tube and the immersion nozzle of the tundish are replaced, and the first tundish 3-1 is continuously used without preheating. The casting time from the end of casting of the continuous casting machine to the start of the next casting is about 15 to 17 minutes, and the hot maintenance can be performed in about 10 to 12 minutes.

When the first tundish 3-1 is used for 5 trials, or when an abnormality occurs in the refractory, etc., in addition to the replacement of the injection pipe and the immersion nozzle of the tundish, the cassette refractory of the sliding nozzle device, Perform hot maintenance such as thermal spraying and spray repair of the bottom of the tundish. This hot repair takes about 20 to 30 minutes.

It takes about 30 to 60 minutes for hot maintenance such as replacement of consumable parts of the first tundish 3-1 and thermal spraying / spraying of refractories, so that 5 trials of the first tundish are required. At the same time, the second tundish 3-2 preheated and waiting at the position of the tundish preheating device 11 is transferred to a casting tundish car 12-1 by an overhead crane, and an immersion nozzle or the like is attached thereto. As with the first tundish, 2 tundishes 3-2 are used continuously, with 5 trials, no repairs, and only replacement of consumables.

First tundish 3 after hot repair
-1 is transported to a preheating tundish car 12-2 by an overhead crane, and is preheated and put on standby so that it can be used for the next trial. By repeating the above, stable operation with high efficiency is performed with two tundishes.

The cast floor 10 has a tundish hot waste / hot maintenance facility 20 on one side, and a tundish preheating device 11 and a preheating tundish car 12- on the other side.
2 and two tundishes are sufficient, so that the cast floor equipment can be made compact and inexpensive,
It is also possible to modify the casting floor of an existing continuous casting machine.

[0026]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a first embodiment of the present invention; This is an example in which an existing two-strand continuous casting machine is modified. Note that the same reference numerals are given to the same or corresponding parts as those in the related art.

FIG. 1 is a schematic plan view showing a casting floor facility according to the present invention. In the present invention, a tundish preheating apparatus 11 at a preheating standby position b in a casting floor of a conventional existing continuous casting machine shown in FIG. -1 and the tundish preheating device 11-2 and the tundish car 1 at the preheating standby position c.
2-2 and one tundish preheating device 11
And two tundish cars 12-1 and 12-2.

The tundish car 12-1 on the b side is dedicated to casting, and can reciprocate between a casting position a and a position b-2 described later. The c-side tundish car 12-2 is dedicated to preheating, does not reciprocate, is fixed, and is used as a support base for supporting the tundish 3.

Further, a side of the casting floor 10 dedicated to the casting tundish car 12-1 is slightly added, and a tundish hot waste / hot maintenance facility 20 is installed there. The tundish hot waste / hot maintenance yard has an intermediate standby position b-1 and a repair position b-2 which are successively arranged in the side of the casting position a.
And a tilt position b-3 located parallel to the repair position b-2.

At the intermediate standby position b-1, an injection pipe exchange device 21, an immersion nozzle exchange device 22, and the like are installed. At the repair position b-2, a cassette refractory exchanging device 23 for a sliding nozzle, a refractory spraying / spraying device 24, and the like are provided. At the tilting position b-3, a tilting device 25 for tilting the tundish 3 and a slag pan for receiving the residue and the residual steel are installed, and the tilting device 25 reciprocates to the repair position b-2. Crane structure will be used.

The injection pipe changing device 21, the immersion nozzle changing device 22, the sliding nozzle cassette refractory changing device 23, and the refractory spraying / spraying device 24 may be operated automatically by an automatic robot or the like. The work may be performed manually.

With the above configuration, continuous casting is performed as follows (see FIG. 2).

(1) Tundish car for casting 12-1
Is moved to the pouring position a, and molten steel from the ladle 1 is poured into the mold through the No. 1 tundish 3-1. At the start of casting, the molten steel in the ladle 1 is poured into the tundish 3, and the slag and oxides adhered to the inner surface of the tundish 3 are taken into the molten steel by the molten steel flow, separated and floated, and a specified amount of molten steel is formed. After being stored, it is poured into the mold 4 to start casting. Heating or stirring may be performed to promote the separation and floating of the attached slag and oxide.

(2) When one trial of continuous casting is completed, the casting-only tundish car 12-1 reaches the intermediate standby position b.
To move. During this movement, the immersion nozzle 7 and the tundish injection tube 5 are removed. The tundish lid 8
Is left attached.

(3) Tundish car for casting 12-1
Is further moved to the repair position b-2, and N
o.1 The tundish 3-1 is lifted by the tilting device 25,
It is moved to the tilting position b-3, where the waste is discharged by tilting.

(4) When the processing of the residue is completed, the tilting device 25 moves the No. 1 tundish 3-1 to the repair position b-2.
And put on the tundish car 12-1 for casting. Subsequently, the casting-only tundish car 12-1 is moved to the intermediate standby position b-1, where the dipping nozzle 7 on the lower surface of the tundish is attached, and at the same time, the tundish injection pipe 5 on the upper surface of the tundish is attached.

As described above, the preparation for the next casting was completed, and during this period (from the end of casting to the completion of casting preparation), the series of hot maintenance of the tundish was completed in 10 to 12 minutes. Immediately after the end of casting, the above-mentioned simple maintenance is performed in a hot state. Therefore, the temperature of the tundish decreases very little until the end of the next casting, and there is no need for preheating. The time from the end of casting to the start of the next casting takes 15 to 17 minutes due to insertion of a dummy bar or the like, but preparation of the tundish is completed within this time.

(5) The No. 1 tundish 3-1 which has been hot-prepared as described above is continuously used, for example, for 5 trials. When this continuous casting is repeated for 5 trials, the No. 1 tundish 3-1 after completion of casting is removed from the immersion nozzle 7 and the like at the intermediate standby position b-1 and the waste is discharged at the tilting position b-3. At the repair position b-2, the caster is lowered from the casting-only tundish car 12-1 and placed on the floor to perform thermal spraying / spray repair of the refractory, and replace the refractory of the sliding cassette of the sliding nozzle device 6. Casting tundish car 12-
1 is moved to the intermediate standby position b-1.

(6) It takes 30 to 60 minutes to perform such repair and refractory replacement. Therefore, the tundish preheating device 11 in the tundish preheating device 12 in the preheating dedicated tundish car 12-2 is used. No.2 tundish 3-
2 at the intermediate standby position b-
Casting tundish car 12-1 waiting at 1
Then, the immersion nozzle 7 is attached, the casting-only tundish car 12-1 is moved to the casting position a, and the next continuous casting is performed with this No. 2 tundish 3-2.
Repeat multiple times.

(7) On the other hand, the No. 1 tundish 3-1 whose repair or refractory replacement has been completed is transferred onto a preheating dedicated tundish car 12-2 by an overhead crane 14, and It is preheated and ready for the next casting.

As described above, the two tundishes 3 were constantly rotated for 15 to 17 minutes to perform high-efficiency casting. Here, when a tundish having a capacity of 85 tons was used, the following effects were obtained as compared with the casting floor equipment (FIG. 3) in a conventional existing continuous casting machine.

Since the tundish is repeatedly used while hot, the number of the tundish can be greatly reduced.

Since the temperature of the inner surface of the tundish does not decrease to a temperature at which the residual steel and the residue adhere, there is no work to remove the adhered substance, there is no wear of the refractory, and there is no transportation to the maintenance yard unlike the conventional case. Since the temperature change on the inner surface of the tundish can be reduced, the life of the tundish refractory can be improved.

By improving the life of the refractory and reducing the number of tundishes, the cost of the tundish refractory can be reduced to 1/8 or less of the conventional cost.

Since the tundish is repeatedly used while hot, the tundish is not substantially preheated, so that the amount of C gas, electric power, and oxygen used for heating the tundish can be reduced.

Since there is no need to transport the tundish to the maintenance yard, the number of maintenance personnel for the tundish can be reduced.

Further, the following effects can be obtained as compared with the conventional hot maintenance method.

The conventional hot maintenance method requires a wide casting floor and can be applied only to a newly installed continuous casting machine. However, it can be applied to an existing continuous casting machine.

The remodeling cost is 1/8 of the new construction cost
1/10 has become possible, and the tundish hot reuse can be performed at low cost.

In the case of a multi-strand, four to five tundishes were conventionally required, but only two are required.
In addition, the number of personnel was reduced by using both operating and maintenance personnel.

The remodeling period can be minimized, and one week to one
In 0 days (5 days x 2 times), it was possible to shorten the time required for remodeling work and stoppages (stopping existing production facilities for a long time is a serious problem for steelworks).

[0052]

As described above, according to the present invention, a tundish car for exclusive use of casting and a tundish hot waste and hot maintenance facility are installed on one side of the center line of the continuous casting machine, and the other side is provided. A tundish car and a tundish preheating device are placed in the tundish, and the first tundish is repeatedly used in a hot state. If the first tundish needs hot repair, the second tundish is repeatedly used. As a result, the following effects can be obtained.

(1) Unlike the conventional hot maintenance method, it is not necessary to dispose tundish hot waste / hot maintenance equipment on both sides of the continuous caster, and it is not necessary to dispose one of the existing continuous casters. The tundish preheating device and the tundish car on the side can be used, and the equipment cost can be reduced.

(2) In the case of a multi-strand, four to five tundishes are required in the conventional hot maintenance method, but in the present invention, two tundishes are used to perform highly efficient and stable operation. be able to.

(3) The cast floor equipment can be made compact and simple with one tundish hot waste / hot maintenance equipment and two tundishes. Can also be applied. In addition, equipment costs and remodeling costs can be reduced, and remodeling work can be speeded up.

(4) Since hot waste / hot maintenance equipment is provided only on one side and only two tundish units are required, the number of tundish personnel can be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic plan view showing a casting floor facility of a continuous casting machine according to the present invention.

FIG. 2 is a flowchart showing a method for using a tundish according to the present invention.

FIG. 3 is a schematic plan view showing a conventional existing casting floor facility.

FIG. 4 is a partial sectional view of the cast floor equipment of FIG. 3;

5 is a flowchart showing a method of using a tundish in the cast floor facility of FIG.

FIG. 6 is a schematic plan view showing a conventional cast floor facility for performing hot maintenance.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Ladle 2 ... Ladle turret 3 ... Tundish 4 ... Mold 5 ... Tundish injection pipe 6 ... Sliding nozzle device 7 ... Immersion nozzle 8 ... Tundish lid 10 ... Casting floor 11 ... Tundish preheating device 12-1 ... Casting tundish car 12-2 ... Preheating tundish car 14 ... Overhead crane 20 ... Tundish hot waste / hot maintenance equipment 21 ... Injection pipe exchange device 22 ... Immersion nozzle exchange device 23 ... Sliding nozzle cassette fireproof Material exchange device 24: Refractory spraying and spraying device 25: Tilting device

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) B22D 11/10 310 B22D 41/00 B22D 43/00

Claims (3)

(57) [Claims] 1. Casting molten steel in a ladle into a mold via a tundish, and after casting is completed, only the slag remaining in the tundish used for the casting, or slag and steel are hot-discharged, and In the continuous casting method in which hot maintenance without substantially cooling the tundish is performed and the next casting is performed using the tundish thus maintained, the center line of the continuous casting machine in the casting floor of the continuous casting machine is used. A tundish hot waste / hot maintenance facility is provided on one side with the tundish preheating device provided on the other side, and the tundish hot waste / When the next casting is performed by performing the processing of the residue or the remaining steel and the replacement of the tundish consumable parts in the hot maintenance equipment, and the casting by the first tundish is repeated a plurality of times, Performs the repair or the like of the refractory material in the tundish hot Haikasu-hot maintenance equipment for a tundish,
A method for using a tundish in a continuous casting machine, wherein casting is continued in a second tundish that has been preheated and waited in the tundish preheating device. 2. A tundish preheating device on one side of a tundish preheating device and a tundish car disposed on both sides of a continuous casting machine center line in a casting floor facility of an existing continuous casting machine. A method for remodeling a continuous casting machine, which comprises removing a device, adding a hot-draining and hot-maintenance facility for a tundish, and using a tundish preheating device and a tundish car on the other side. . 3. A tundish preheating device and a preheating-only tundish car are disposed on one side of the center line of the continuous casting machine, and a casting-only tundish car and a tundish hot waste are disposed on the other side. -Casting floor equipment for continuous casting machines characterized by hot maintenance equipment.