JPH07112599B2 - Casting start method and dummy bar device of belt type continuous casting machine - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for starting casting in a belt type continuous casting machine for continuously casting a slab and a dummy bar device used for the method.

[Prior Art] FIG. 5 is a side conceptual view showing an example of a conventional belt-type continuous casting facility. As shown in the figure, a pair of side dams 51 having the same thickness as the required thin slab and arranged at intervals of the same plate width and rotating endlessly in the thin slab drawing direction as indicated by an arrow. , A pair of belts 52 wound around a pulley 53 to hold both side dams 51 and rotate in synchronization with the side dams 51, and an upper surface having the same thickness and width as the thin slab (thin slab fixing surface). Molten steel is continuously supplied from a dipping nozzle 56 of a tundish 55 to a mold formed by a dummy bar 54 having a solid bar and solidified to cast a thin slab.
The thin slab solidified on the upper surface of the dummy bar 54 and fixed by the connecting rod 23 is led by the dummy bar 54 and pulled out from the mold. Then, the thin slab is guided by the guide roller 57 arranged on the drawing path of the thin slab, drawn out from the mold by the pinch roll 58 for the dummy bar 54, and the thin slab is continuously drawn out by the slab drawing device 59. Next, the tip of the thin slab (near the connection with the dummy bar) was cut by the dummy bar cutting device 60 and removed.
54 is temporarily stored in the storage device 61.

Dummy bar 54 for general continuous casting machines as well as belt type continuous casting machines
As shown in the example, the has a structure in which small blocks are connected to each other by a pin hinge in a chain shape, and is configured so as to follow a curved slab withdrawal guide.

[Problems to be solved by the invention]

As shown in Fig. 5, the purpose of the dummy bar is to form the temporary bottom of the mold at the start of casting and to pull out the slab from the mold continuously. I will end up.

Moreover, since the length of the conventional dummy bar requires the length from the mold to the roll supporting the dummy bar, the length is generally 10 m at the shortest and 20 m or more at the longest, which is large. It becomes a hanging device. Furthermore, it is necessary to install not only the dummy bar but also its storage device, and the equipment cost and the cost required for maintenance work account for a large proportion of the function, and improvement and cost reduction are required from the beginning of commercialization of the continuous casting machine. It was unresolved despite it being done.

SUMMARY OF THE INVENTION The present invention is intended to provide a casting start method and a dummy bar device used in the method for solving the above problems in a belt type continuous casting machine.

[Means for solving problems]

A casting start method for a belt type continuous casting machine according to the present invention includes a pair of belts arranged parallel to each other and rotating in opposite directions, and a large number of blocks provided on both sides of the belt and moving together with the belt. Injecting molten metal into the mold formed by the movable side dam configured with, in the belt type continuous continuous machine for continuously drawing out the slab solidified in the slab, in starting the casting, in the mold After making the lower half of the side dam of the located portion inward of the mold to form a stepped portion, a block-shaped dummy bar head having a size and shape almost equal to the upper cross section of the mold is formed from the upper part of the mold. It is characterized in that a temporary bottom of the mold is formed by inserting and supporting it on the stepped portion of the side dam, and the molten metal is injected into the mold.

Further, the dummy bar device according to the present invention is used directly in the casting method of the present invention, and includes a pair of belts arranged parallel to each other and rotating in opposite directions, and on both sides of the belt. Injecting molten metal into a mold formed by a movable side dam configured with a number of blocks provided and moving together with a belt, in a dummy bar device for continuously drawing out a slab solidified slab,
It is characterized by comprising a block-shaped dummy bar head having a size and shape substantially equal to the size and shape of the inside of the mold, and a connecting rod of a slab that is detachably attached to the upper side of the dummy bar head.

[Work]

In the method according to the present invention, after the lower half of the side dam of the portion located in the mold is extruded inward of the mold to form a stepped portion, a size and shape approximately equal to the upper cross section of the mold are obtained. A block-shaped dummy bar head is inserted from the top of the mold and supported by the stepped portion to form a temporary bottom of the mold, and then molten metal is injected to start casting. When the molten metal forms a molten metal surface of a predetermined height on the temporary bottom, the side dam block and the belt are moved at a predetermined speed while the dummy bar head is supported by the stepped portion to move the dummy bar head to the side dam block. And move it with the belt. By the time the dummy bar head is pulled out of the mold, the lower part of the molten metal is cooled and solidifies into a slab, which is fixed to the dummy bar head. The above-described movement of the dummy bar head in the mold part is performed at a predetermined speed together with the side dam block and the belt by the block-shaped dummy bar head being supported by the stepped part and being held by the pair of belts.

The dummy bar device that has left the mold is continuously pulled out by the guide roller and the pinch roller.

As described above, according to the method of the present invention, the temporary bottom of the mold can be made by a simple operation of placing the dummy bar head on the stepped portion of the side dam block, and casting is performed without using a long dummy bar. You can start.

Conventionally, a normal dummy bar has a length of 20 m or more in a 10 m long one, but according to the present invention, the dummy bar head only needs to have a strength length capable of supporting a slab, for example, a slab with a width of 2 m. But the length of the dummy bar head can be less than 500mm.

Further, the dummy bar device according to the present invention is a dummy bar device which is directly acted on by the casting start method, and is supported by the stepped portion of the side dam block at the start of the casting inserted from the upper part of the mold and the mold is supported. A false bottom is formed.
When pouring is started in the mold thus formed and the molten metal reaches the predetermined molten metal surface level, the side dam block, belt and dummy bar device move as described above, and when the molten metal solidifies, the dummy bar head The slab is fixed to the dummy bar by the connecting rod, and the slab is led by the dummy bar device to surely move from the inside of the mold to the outside of the mold. Further, since this connecting rod is detachably attached to the dummy bar head, when the formed slab is cut near the fixed portion with the dummy bar head, it was cut by removing the connecting rod from the dummy bar head. The tip of the slab can be easily removed from the dummy bar head. Further, the dummy bar head separated from the tip of the slab in this way can be repeatedly used by newly mounting the connecting rod.

〔Example〕

An embodiment of the present invention will be described with reference to FIGS.

In FIG. 1 to FIG. 4, A ₁ , A ₂ and B ₁ , B ₂ are double-structured, respectively, as indicated by arrows by respective electric actuators 10a, 10b attached to a fixed portion (not shown). Side dams 1a and 1b, which are a pair of moving guide plates and occupy a half circumference on _one guide plate A ₁ or B ₁ of the double structure, are chain links 11 and guide rollers 1.
It is guided by the groove 13 ′ through the guide plate A ₁ , B ₁
Sprocket 3a, 3 connected to a drive mounted on
b meshes with the chain link 11.

Also, on the other guide plates A ₂ and B ₂ , the side dams 2a and 2b occupying the remaining half circumference are also guided by the groove 13 ″ through the chain link 12 and the guide roller 13. These right in FIG. The side dams 1a, 2a on the one side and the side dams 1b, 2b on the left side are connected endlessly by chain links 11, 12, respectively, and rotate by the sprockets 3a, 3b as indicated by arrows, for example, one guide plate.
Side dam 1a, which occupies a half circumference by moving A ₁ and B ₁ relative to each other,
By moving 1b relative to the side dams 2a, 2b occupying the remaining half circumference, the plate width of the thin slab S can be changed even during casting. Also,
The plate thickness of the thin slab S is determined by the thickness of the side dams 1a, 2a; 1b, 2b. A belt 4 is wound around pulleys 5a to 5c, holds both side dams 1a, 2a; 1b, 2b, and rotates in synchronization with the side dams 1a, 2a; 1b, 2b.

Reference numeral 6 denotes a block-shaped dummy bar head, on the upper surface of which a heat insulating plate 8 such as an asbestos sheet is fixed, and a connecting rod 7 is fitted and fixed by a bolt 9 screwed into a screw hole of the dummy bar head 6. Has been done.

As shown in FIG. 1, the sprockets 3a, 3b are rotated to set the boundary between the upper side dams 1a, 1b and the lower side dams 2a, 2b at a predetermined position in the mold, and the upper side dom 1
The guide plates A ₁ and B ₁ to which a and 1b are mounted are relatively moved to set the plate width of the thin slab S, and the guide plates A ₂ and B ₂ to which the lower side dams 2a and 2b are mounted are By moving toward the center and pushing the block group of the side dams 2a, 2b inward, the interval between the side dams is narrowed, and a stepped portion D is provided at the boundary with the upper side dams 1a, 1b. Then, in the stepped portion D, the block-shaped dummy bar head 6
After suspending and supporting to form the temporary bottom of the mold,
Molten steel is poured from the immersion nozzle 56 of the tundish 55.
When the molten steel forms a predetermined molten metal level, the side dam 1 again
a, 1b; 2a, 2b and the belt 4 are rotated at a predetermined speed, and the lower part of the molten steel is cooled and solidified into a thin slab S by the connecting bar 7 until the dummy bar head 6 is extracted from the mold part. It is fixed to the dummy bar head 6. After that, the dummy bar head 6 and the thin slab S are guided by the guide roller 57 as shown by the chain double-dashed line in FIG. 1, and continuously pulled out by the pinch roll (not shown).

At the start of continuous casting, the position where the dummy bar head 6 is set is determined from the depth of the molten steel pool that ensures solidification at the initial stage of casting in relation to the tundish 55 and the immersion nozzle 56 provided under the tundish 55. To be done.

The thin slab S guided by the dummy bar head 6 is cut in the vicinity of the fixed portion at the tip thereof as in the prior art device. However, the dummy bar head 6 loosens the bolt 9 so that the connecting rod 7 becomes a dummy bar. The tip end of the thin slab S that has been cut off easily from the head 6 can be easily removed from the dummy bar head 6, and the connecting rod 7 can be reused by newly mounting it on the dummy bar head 6.

As described above, in the present embodiment, the dummy bar head 6
The casting can be started by a simple operation of inserting the mold from the upper part of the mold and supporting it on the stepped portion S of the side dam guide, and when the molten metal reaches the molten metal surface of a predetermined height, the side dam block and the belt. Is moved to move the dummy bar head 6 while being held by the belt 4, so that the block-shaped dummy bar head 6 having a short length can start casting.

Further, the thin slab S can be fixed to the connecting rod 7 on the dummy bar head 6 so that the slab S can be surely led.
When cutting the thin slab S, the dummy bar head 6 can be used again by removing the connecting rod and mounting a new connecting rod as described above.

〔The invention's effect〕

In the method of the present invention, in a belt-type continuous casting machine using a pair of belts and side dams, casting can be started by a simple step of setting a block-shaped dummy bar head on the stepped portion of the side dams in the mold. it can. Further, since a long dummy bar as in the prior art is not required, the dummy bar body and its storage device are not required, and the equipment cost is greatly reduced and the area around the slab unloading device is simplified.

Further, the dummy bar device of the present invention is used in the present invention, and the slab formed by the connecting rod is firmly fixed to the dummy bar head so that the slab can be surely led at the start of casting. Also, after cutting the slab, the connecting rod can be used again by removing it from the dummy bar head and mounting a new connecting rod.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view showing a state immediately before starting casting by setting a dummy bar head in a belt type continuous casting machine in one embodiment of the present invention, and FIG. 2 is a sectional view taken along line II-II of FIG. 3 (a) is a partially enlarged view showing the mounting state of the connecting rod to the dummy bar head, and FIG. 3 (b) is III b in FIG. 3 (a).
-IIIb sectional view, FIG. 4 is an IV-IV sectional view of FIG. 1, and FIG.
The figure is a side view showing the arrangement of each member of the conventional belt type continuous casting equipment. 1a, 1b, 2a, 2b …… side dam, 4 …… belt, 6 …… dummy bar head, 7 …… connecting rod, 10a, 10b …… electric actuator, 11,12 …… chain link, 13 …… guide roller, A ₁ , A ₂ ,
B ₁ , B ₂ …… Guide plate, S …… Thin slab, D …… Side dam step.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kanji Shozen 4-6-22 Kannon Shinmachi, Nishi-ku, Hiroshima City, Hiroshima Prefecture Mitsubishi Heavy Industries Ltd. Hiroshima Works (56) Reference JP-A-63-290656 (JP, A) )

Claims (2)

[Claims] 1. A pair of belts arranged parallel to each other and rotating in opposite directions, and a movable side dam composed of a plurality of blocks provided on both sides of the belt and moving together with the belt. Injecting molten metal into a mold to be cast, in a belt type continuous casting machine that continuously draws out a slab solidified in a slab, in starting casting,
A block-shaped dummy bar head having the same size and shape as the upper cross section of the mold after the lower half of the side dam of the part located in the mold is extruded inward of the mold to form a stepped portion. By inserting it from the upper part of the mold and supporting it on the stepped part of the side dam to form a temporary bottom of the mold, and casting the molten metal into the mold to cast a belt-type continuous casting machine. How to get started. 2. A pair of belts arranged parallel to each other and rotating in opposite directions, and a movable side dam composed of a plurality of blocks provided on both sides of the belt and moving together with the belt. In a dummy bar device for injecting molten metal into a mold to be formed and continuously drawing out a slab-solidified slab, a block-shaped dummy bar having a size and shape substantially equal to the inner shape and shape of the mold. A dummy bar device for a belt-type continuous casting machine, comprising a head and a connecting rod of a slab that is detachably inserted on the upper side of the dummy bar head.