JPH07223059A - Method for protecting cast strip continuous caster from breakout - Google Patents

Abstract

PURPOSE:To prevent the damage of devices caused by spattering of leakage of molten metal at the time of developing breakout, in a cast strip continuous caster having a shifting mold. CONSTITUTION:On the way of a course feeding out a cast strip 4 from the cast strip continuous caster, the feeding out course for cast strip 4 is changed with a support roll 16 connected with a hydraulic cylinder 21 through a rod 20. The leaked molten metal dropped at the time of developing the breakout is received with a trough-like breakout cover 13 arranged below the molds 1a, 1b and also, stored in a molten metal pot 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a thin cast slab continuous casting machine having a moving mold such as a twin roll or twin belt type,
The present invention relates to a protective method and a device for preventing damage to equipment and a pedestal due to splashing of molten metal at breakout.

[0002]

2. Description of the Related Art A thin cast continuous casting machine for injecting a molten metal between a pair of cooling rolls or cooling belts rotating inward and rapidly solidifying the molten metal to produce a thin metal plate is a conventional casting machine. The process and equipment can be simplified because the rolling to the final shape does not require a step of hot rolling and is light.

FIG. 5 shows an example of casting by a twin-roll continuous casting machine in this thin cast slab continuous casting apparatus. This casting machine comprises a pair of cooling rolls 1a, 1b which rotate in opposite directions to each other. The roll gap 3 corresponding to the plate thickness to be manufactured is arranged, and both ends in the roll axial direction are partitioned by the side dams 24a and 24b to form the molten metal pool 2.

When the molten metal is poured into the pool 2 from above by the pouring nozzle 22, the molten metal is rotated inward while the molten metal is poured into the cooling rolls 1a and 1b.
When the cooling rolls 1a and 1b are contacted with each other and heat is removed, solidification shells 23a and 23b are formed on the surfaces of the cooling rolls 1a and 1b.
3a and 23b are joined while the cooling rolls 1a and 1b are rotated as they grow, and are further pressed by the roll gap 3 to form a thin cast piece 4 having a predetermined thickness.
It is delivered below 1b to produce a metal sheet.

By the way, in such a continuous casting machine,
If an abnormality occurs in any of casting conditions such as pouring amount, cooling roll rotation speed, cooling roll heat removal balance, roll gap, etc., solidification shell formation in the roll gap becomes incomplete and solidification in the roll gap occurs. A so-called breakout phenomenon occurs in which the shell is not solidified and is discharged downward to eject the molten metal.

Once this breakout occurs, the leaked molten metal falls on the rolling mill, rolling down roll, guide roll, pinch roll, etc. arranged under the cooling rolls and damages the equipment. In addition, the operation is stopped during the restoration work, which causes a great loss in productivity.

The present inventor, in Japanese Patent Application No. 05-311036, attaches a molten metal pot having a gutter-shaped breakout cover or a gutter-shaped breakout cover at its tip to the end of a telescopic rod, and the break We have proposed a breakout protection device in which an out cover or a molten metal pot is installed relative to each other around a path for feeding a slab from a thin cast slab continuous casting machine having a movable mold. However, this method requires a measuring device for detecting a breakout and a control device for activating the breakout protection device, which complicates the device.

[0008]

DISCLOSURE OF THE INVENTION The present invention is a thin cast slab continuous casting machine having a pair of movable molds such as twin rolls and twin belts, which prevents leakage of molten metal at breakout without detecting breakout. Provided is a breakout protection method and apparatus for preventing damage to lower equipment and a pedestal due to splashing, especially a large amount of leaked water.

[0009]

DISCLOSURE OF THE INVENTION The present invention is directed to a thin-walled casting by contacting a support roll with the thin-walled slab on the way of delivering the thin-walled slab from a continuous casting machine for the thin-walled slab having a pair of movable molds. Continuous casting of thin-walled cast pieces characterized by changing the delivery path of the pieces and receiving the leaking metal at the breakout at the time of breakout by the gutter-shaped breakout cover installed below the mold and storing it in the molten metal pot. This is a machine breakout protection method.

Further, according to the present invention, a support roll is installed below one of the molds of a continuous casting machine for thin-walled slabs having a pair of movable molds, and a gutter-shaped slant is provided just below the feeding portion for the thin-walled slabs. Provided is a breakout protection device for a continuous casting machine for thin-walled slabs, in which a breakout cover is installed and a molten metal pot is installed at the lower end of the inclined breakout cover.

[0011]

Before or immediately after the start of casting, the feeding direction of the dummy sheet or the thin-walled slab is changed by the support rolls, and the inclined breakout cover is installed immediately below the pair of moving molds.

When the casting conditions become abnormal due to some cause, the solidified shell is not completely formed in the gap of the moving mold of the thin cast continuous casting machine, and a so-called breakout in which the molten metal is ejected occurs, the falling leakage. The molten metal is received by a slanted gutter-shaped breakout cover installed below the moving mold, and it is poured along it and poured into a molten metal pot installed at its lower end to prevent downward scattering of the moving mold, and the molten metal source is closed during this time. Then, the inflow of the molten metal into the movable mold is blocked.

[0013]

FIG. 1 shows an example in which the present invention is applied to a twin roll type continuous casting machine.

A pair of cooling rolls 1a and 1b are arranged with an appropriate roll gap 3 to form a basin 2 between the pair of cooling rolls 1a and 1b, and the molten metal injected is paired with the cooling rolls 1a and 1b. When contacted with the cooling roll 1 to remove heat, a solidified shell is formed
They are joined together with the rotation of a and 1b, and are further pressed by the roll gap 3 to form a thin cast piece 4 having a predetermined thickness, which is delivered below the cooling rolls 1a and 1b.

The breakout protection device includes a hydraulic cylinder 9 via a rod 8 in the middle of the delivery path of the thin cast piece 4.
Movable trough-shaped breakout cover 5 connected to
The breakout cover 5 is provided with a through hole 25 through which the thin cast piece 4 is passed and a support roll 7 for pressing the thin cast piece 4.

A molten metal pot 6 for storing the leaked molten metal 12 is installed below one end of the breakout cover 5.

Here, in the case of the steady casting state shown in FIG. 1, the roll gap 3 between the pair of cooling rolls 1a and 1b.
The thin cast piece 4 delivered from the through-hole is passed through the through hole 25 provided in the breakout cover 5, and is continuously brought into contact with the support roll 7 to change the delivery path of the thin cast piece 4 to be installed below the pinch. It is sent to the rolls 10a and 10b and the rolling mills 11a and 11b.

FIG. 2 is a diagram showing the operation of the protective device when a breakout occurs.

A pair of cooling rolls 1 due to breakout
The molten metal 12 ejected from the roll gap 3 between a and 1b is poured along a trough-shaped breakout cover 5 into a molten metal pot 6 installed below one end thereof, and the molten metal source is closed during this period. The inflow of the molten metal into the pool 2 is blocked.

As a construction example of the breakout protection device,
An experiment was conducted using a pair of internally cooled cooling rolls having a diameter of 600 mm and a width of 600 mm in the breakout protection device of the twin roll type continuous casting apparatus shown in FIG.

Initial molten steel temperature 1491 ° C., casting speed 65 m
/ Min., When casting SUS304 stainless steel under the condition that the thickness of the thin slab is 2.5 mm, the superheat degree of the molten metal was gradually increased to cause a pseudo breakout. It was confirmed that the effect of the present invention can be prevented.

Here, in the first embodiment, the breakout cover 5 and the support roll 7 are attached to the expandable rod 8 so as to be movable, but the breakout cover 5 and the support roll 7 are fixedly installed. Good.

Although the breakout cover 5 and the molten metal pot 6 are separately installed, they may be integrally installed.

Although the support roll 7 is of a non-driving type, it may be driven by installing a driving motor.

FIG. 3 shows another example in which the present invention is applied to a twin roll type continuous casting machine.

A pair of cooling rolls 1a and 1b are arranged with an appropriate roll gap 3 to form a basin 2 between the pair of cooling rolls 1a and 1b, and the molten metal injected is paired with the cooling rolls 1a and 1b. When contacted with the cooling roll 1 to remove heat, a solidified shell is formed
They are joined together with the rotation of a and 1b, and are further pressed by the roll gap 3 to form a thin cast piece 4 having a predetermined thickness, which is delivered below the cooling rolls 1a and 1b.

In the breakout protection device, a support roll 16 that is connected to a drive motor 17 via a drive belt 18 and can be driven is provided in the middle of the delivery path of the thin cast piece 4.
It is installed on a moving carriage 19 connected to a hydraulic cylinder 21 via a rod 20 together with the drive motor 17, and is also an inclined gutter-shaped connected to the hydraulic cylinder 15 via a rod 14 on the opposite side. A breakout cover 13 is installed.

A molten metal pot 6 for storing the leaked molten metal 12 is installed below one end of the breakout cover 13.

Here, in the case of the steady casting state shown in FIG. 3, the roll gap 3 between the pair of cooling rolls 1a and 1b is used.
The thin cast slab 4 sent from the above is brought into contact with the support roll 16 to change the delivery path of the thin slab 4 and the breakout cover 13 is installed below the roll gap 3 between the pair of cooling rolls 1a and 1b. , Continued thin-walled slab 4
Is sent to the pinch rolls 10a and 10b and the rolling mills 11a and 11b installed below the support roll 16.

FIG. 4 is a diagram showing the operation of the protective device when a breakout occurs.

In this way, the molten metal 12 spouted from the roll gap 3 between the pair of cooling rolls 1a and 1b due to the breakout is installed along the trough-shaped breakout cover 13 and below one end thereof. The molten metal is poured into the molten metal pot 6, and the molten metal source is closed during this period to block the inflow of the molten metal into the molten metal pool 2.

As a construction example of the breakout protection device,
An experiment was conducted using a pair of internally cooled cooling rolls having a diameter of 600 mm and a width of 600 mm in the breakout protection device of the twin roll type continuous casting device shown in FIG.

Initial molten steel temperature 1497 ° C., casting speed 68 m
/ Min., When casting SUS304 stainless steel under the condition that the thickness of the thin-walled slab is 2.4 mm, the superheat degree of the molten metal was gradually increased to cause a pseudo breakout. It was confirmed that the effect of the present invention can be prevented.

In the second embodiment, the breakout cover 13 and the support roll 16 are connected to the rod 14,
Although the hydraulic cylinders 15 and 21 are connected to each other via 20 to be movable, the breakout cover 13 and the support roll 16 may be fixedly installed.

Although the breakout cover 5 and the molten metal pot 6 are separately installed, they may be integrally installed.

Further, in the second embodiment, the support roll is driven, but it may be non-driven.

Although only the twin roll type continuous casting apparatus is shown in the first and second embodiments, the present invention is also effective for the twin belt type continuous casting apparatus.

In FIGS. 1 and 3, the support roll and the gutter-shaped breakout cover are connected to a hydraulic cylinder so as to be movable, which facilitates maintenance such as preparation for mounting a dummy sheet and replacement of a moving mold. This is because.

[0039]

As described above, according to the protective device of the present invention, the support roll, the gutter-shaped breakout cover, and the molten metal pot are installed in the slab feeding part of the thin slab continuous casting machine having the movable mold. Thus, even if a breakout occurs, damage to the equipment and the pedestal due to the spouting of the molten metal can be prevented, and the recovery time can be shortened to stabilize the operation and improve the productivity.

[Brief description of drawings]

FIG. 1 shows a first embodiment of the present invention, showing a case of a twin roll type continuous casting machine in a steady casting state.

FIG. 2 shows the operation of the protective device when a breakout occurs in the first embodiment.

FIG. 3 shows a second embodiment of the present invention, showing a case of a twin roll type continuous casting machine in a steady casting state.

FIG. 4 shows the operation of the protective device when a breakout occurs in the second embodiment.

FIG. 5 shows an example of a conventional twin roll type continuous casting device,
(A) is a schematic side view, and (b) is a bird's-eye view thereof.

[Explanation of symbols]

 1a, 1b ... Cooling roll 2 ... Hot water pool 3 ... Roll gap 4 ... Thin cast piece 5, 13 ... Breakout cover 6 ... Molten pot 7, 16 ... Support roll 8, 14, 20 ... Rod 9, 15, 21 ... Hydraulic cylinders 10a, 10b ... Pinch rolls 11a, 11b ... Rolling mill 12 ... Molten metal 17 ... Drive motor 18 ... Drive belt 19 ... Moving carriage 22 ... Pouring nozzles 23a, 23b ... Solidification shells 24a, 24b ... Side weir

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[Procedure amendment]

[Submission date] April 19, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0011

[Correction method] Change

[Correction content]

[0011]

Before or immediately after the start of casting, the feeding direction of the dummy sheet or the thin-walled slab is changed by the support rolls, and the inclined breakout cover is installed directly below the pair of movable molds .

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0012

[Correction method] Change

[Correction content]

When the casting conditions become abnormal due to some cause, the solidified shell is not completely formed in the gap of the moving mold of the thin cast continuous casting machine, and a so-called breakout in which the molten metal is ejected occurs, the falling leakage. Hot metal
Preventing scattering of mobile was received and along with breakout cover inclined trough that was placed under the mold downward mobile mold pouring the molten metal pot placed at the lower end,
During this time, the molten metal source is closed to block the inflow of molten metal into the movable mold.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0038

[Correction method] Change

[Correction content]

In FIGS. 1 and 3, the support roll and the gutter-shaped breakout cover are connected to a hydraulic cylinder so that they can be moved, which facilitates maintenance such as dummy sheet attachment preparation and movable mold replacement. This is because

Claims (2)

[Claims] 1. A thin roll slab having a pair of movable molds, a support roll is brought into contact with the thin slab and a delivery route of the thin slab is changed in the middle of the route for delivering the thin slab. A break-out protection method for a continuous casting machine for thin-walled cast slabs, characterized in that a trough-shaped break-out cover installed below the mold receives the leaked metal at the break-out and stores it in the molten metal pot. 2. A support roll is installed below one of the molds of a thin cast slab continuous casting machine having a pair of movable molds,
Furthermore, a slanting gutter-shaped breakout cover was installed just below the delivery part for the thin-walled slab, and a molten metal pot was installed at the lower end of the sloping break-out cover. Protective device.