JP7131325B2 - Thin cast strip manufacturing method and thin cast strip manufacturing apparatus - Google Patents

Description

The present invention provides a thin cast strip manufacturing method and thin cast strip manufacturing apparatus for manufacturing thin cast strips by supplying molten metal to a molten metal pool formed by a pair of cooling drums and a pair of side weirs. It is about.

As a method for producing a thin cast piece of metal, a cooling drum having a water cooling structure is provided inside, molten metal is supplied to a molten metal pool portion formed between a pair of rotating cooling drums, and the outer peripheral surface of the cooling drum is provided. The solidified shells formed on the outer peripheral surfaces of a pair of cooling drums are formed and grown, and the solidified shells formed on the outer peripheral surfaces of a pair of cooling drums are joined to each other at the drum kiss point and rolled down to produce a thin cast slab with a predetermined thickness. Equipment is provided.

Here, when starting casting, for example, as shown in Patent Documents 1 to 4, a dummy sheet is inserted between the cooling drums, and a molten metal pool formed by a pair of cooling drums and a pair of side weirs is used. After the molten metal is supplied to the part and the thin cast strip is formed so as to be connected to the dummy sheet, the cooling drum is rotated to pull out the dummy sheet and the thin cast strip connected to the dummy sheet from between the cooling drums. It is said that

At the start of casting, the casting conditions such as the amount of molten metal supplied to the molten metal pool and the temperature of the cooling drum are not stable, so the strength of the thin cast slab formed so as to be connected to the dummy sheet is insufficient. However, when the dummy sheet was pulled out, trouble occurred such that the thin cast slab was broken, and casting could not be started in some cases. For this reason, conventionally, means for reliably connecting the thin cast piece and the dummy sheet have been proposed.

For example, in Patent Document 1, a reinforcing member made of a material selected from W, Mo, Ta, Nb, and V is joined to the end of the dummy sheet on the side where the cast piece is connected so as to protrude into the pool. No. 3, 2003, a reinforcing material is proposed in which portions coated with ceramics and portions not coated with ceramics are intermingled in the form of vertical stripes. Breakage is prevented by reinforcing the connecting portion between the dummy sheet and the cast piece with a reinforcing material.

Further, Patent Document 2 discloses that a fusible metal foil is attached along the outer peripheral surface of each of the cooling drums to the tip of a dummy sheet inserted into the gap of the cooling drum. By promoting solidification and adhesion of molten steel to the dummy sheet, the joint strength between the dummy sheet and the thin cast slab is improved.

Further, in Patent Document 3, a thin cast piece is provided with a pair of crimping rolls that sandwich a dummy sheet and two crimping dummy sheets that sandwich the thin cast piece directly under the cooling drum, directly below the pair of cooling drums. A manufacturing apparatus is disclosed. The fragile thin cast slab discharged from the cooling drum is sandwiched between crimping dummy sheets using crimping rolls, and the fragile thin cast slab discharged from the cooling drum and the crimping dummy sheet are welded to form a cooling drum. It reinforces the weak part of the thin cast slab discharged from the

In addition, in Patent Document 4, in order to prevent the connecting portion between the thin cast piece and the dummy sheet from breaking and breaking, a length adjustment that allows easy bending deformation is provided near the end on the side where the thin cast piece is connected. A dummy sheet provided with a region is disclosed, and as a specific length adjustment region, a dummy sheet provided with a partial opening is disclosed. The length adjusting area is provided in the vicinity of the connecting portion between the thin cast piece and the dummy sheet for the purpose of preventing the connecting portion from being bent.

JP-A-08-197203 JP-A-01-228650 Japanese Patent Application Laid-Open No. 2004-283870 JP-A-05-138304

By the way, in the apparatus for manufacturing thin cast strips described above, the outer peripheral surface of the cooling drum is provided with a concave crown shape in advance in order to cope with thermal expansion due to heat removal from the molten metal. Therefore, when the tip of the dummy sheet is inserted between the cooling drums before casting, it is difficult to completely fill the gap between the cooling drums.
For example, when the gap between the cooling drums is filled with a strong member, there is a possibility that the surfaces of the cooling drums are locally damaged due to thermal expansion due to the heat of the injected molten metal. On the other hand, when the gap between the cooling drums is filled with a plastic member such as a refractory wool material, leakage of molten steel from the gap between the cooling drums cannot be completely suppressed.

Molten leaks leaking from the gap between the cooling drums impair the soundness of the joint between the dummy sheet and the cast slab.
In addition, if the melted and leaked material adheres to the dummy sheet and solidifies, it will stick to the surface of the subsequent conveying device such as pinch rolls and coilers, and the thin cast slab may not be stably conveyed. There was a possibility that it would not be possible to stably wind up the tape.

Here, as described in Patent Document 3, by sandwiching the dummy sheet and the thin cast piece immediately below the cooling drum with two crimping dummy sheets, the melted and leaked material fixed on the dummy sheet can be covered. Conceivably, it was difficult to stably carry out thin-walled cast slabs to be transported and wound onto a coiler.
Further, as described in Patent Document 4, it is conceivable to drop the melted and leaked material from an opening partially provided in the dummy sheet, but completely suppressing the adherence of the melted and leaked material to the dummy sheet. I couldn't.

The present invention has been made in view of the above-described circumstances, and is capable of suppressing adhesion of molten and leaking substances leaked from between cooling drums to a dummy sheet at the start of casting, thereby stably producing thin cast slabs. It is an object of the present invention to provide a thin cast strip manufacturing method and a thin cast strip manufacturing apparatus that can be conveyed and wound up.

In order to solve the above-described problems, a method for producing a thin cast strip according to the present invention supplies molten metal to a molten metal pool formed by a pair of rotating cooling drums and a pair of side weirs. A method for producing a thin cast slab by forming and growing a solidified shell on an outer peripheral surface to produce a thin cast slab, wherein at the start of casting, one end of a dummy sheet is inserted between the cooling drums in the molten metal pool. When supplying the molten metal to the molten metal pool portion, a cover member is arranged between one cooling drum and the dummy sheet, and the cooling drum The dummy sheet located below the gap is pressed from one cooling drum side by a pressing means having a pressing roll disposed at the tip of the cover member so as to be convex toward the other cooling drum side. and loosening the dummy sheet between the drum kissing point and the pressing position, thereby suppressing the leaked matter that fell downward from between the cooling drums at the start of casting from sticking to the dummy sheet, and After the thin cast piece is pulled out, the pressing means is retracted so as to be separated from the dummy sheet .

According to the thin-walled cast piece manufacturing method of this configuration, a cover member is provided on one of the cooling drums to prevent the material leaking from between the cooling drums from dropping downward when casting is started. Even when the melted leakage falls from between the cooling drums to one of the cooling drums, it is possible to prevent the melted leakage from dropping to the lower side of the cover member and to prevent the melted leakage from adhering to the dummy sheet or the like.
Further, when starting to supply the molten metal to the molten metal pool portion, the dummy sheet located below between the cooling drums is pressed from one cooling drum side and directed toward the other cooling drum side. Therefore, even if molten leakage material falls from between the cooling drums to the other cooling drum side, the molten leakage material slides down along the curved dummy sheet. can be suppressed from adhering to the dummy sheet.
Therefore, since the melted leak does not adhere to the dummy sheet at the start of casting, the thin cast slab can be stably conveyed and wound up.

Here, in the method for producing a thin cast strip of the present invention, the angle θ with respect to the vertical direction of the dummy sheet curved so as to be convex toward the other cooling drum side by the pressing function of the cover member is It is preferable to be in the range of 5° or more and 40° or less.
The angle θ is defined by a line (line A) that passes through the kissing point of the cooling drum and extends vertically below the kissing point, a point where the curved dummy sheet is most distant from the line A in the horizontal direction, and the kiss of the cooling drum. It is defined by the angle formed with the line connecting the points (B line).

The apparatus for manufacturing thin cast strips of the present invention supplies molten metal to a molten metal pool formed by a pair of rotating cooling drums and a pair of side weirs, and forms and grows a solidified shell on the outer peripheral surface of the cooling drums. In the apparatus for manufacturing thin cast strips, the molten metal is supplied to the molten metal pool portion with one end of a dummy sheet inserted between the cooling drums at the start of casting. A cover that covers leaked material that has fallen downward from between the cooling drums at the start of casting between one of the cooling drums and the dummy sheet when the molten metal is supplied to the molten metal pool portion The cover member presses the dummy sheet positioned below between the cooling drums from one cooling drum side by a pressing roll disposed at the tip of the cover member, and presses the dummy sheet from the other cooling drum side. The cover member has a pressing function to bend the dummy sheet so as to be convex toward the cooling drum side of the drum, and loosen the dummy sheet between the drum kiss point and the pressing position. It is characterized in that it has a function of retreating so as to be separated from the dummy seat after being pulled .

According to the apparatus for manufacturing a thin cast slab having this configuration, when starting to supply the molten metal to the molten metal pool section, on one cooling drum side of the dummy sheet, at the start of casting, the flow of water from between the cooling drums Since the cover member is provided to prevent the leaked material from falling onto the dummy sheet, even if the melted leaked material falls from between the cooling drums toward one of the cooling drums, the melted leaking material is melted and leaks to the lower side of the cover member. It is possible to prevent objects from falling, and it is possible to prevent molten and leaking substances from adhering to a dummy sheet or the like.
Moreover, since it has a pressing function of pressing the dummy sheet positioned below between the cooling drums from the side of one cooling drum and curving it so as to be convex toward the side of the other cooling drum, Even if the melted leaking substance falls from between the cooling drums to the other cooling drum side, the melted leaking substance slides down along the curved dummy sheet, and the molten leaking substance can be suppressed from adhering to the dummy sheet. .
Therefore, since the melted leak does not adhere to the dummy sheet at the start of casting, the thin cast slab can be stably conveyed and wound up.

Here, in the apparatus for manufacturing a thin cast strip of the present invention, it is preferable that the pressing position and pressing amount of the dummy sheet can be adjusted by the pressing function.
In this case, it is possible to adjust the pressing position and pressing amount of the dummy sheet according to the casting conditions, and it is possible to more accurately prevent objects falling from between the cooling drums from adhering to the dummy sheet. .

As described above, according to the present invention, at the start of casting, it is possible to suppress adhesion of the molten material leaked from between the cooling drums to the dummy sheet, thereby stably conveying and winding up thin cast slabs. It is possible to provide a thin cast strip manufacturing method and a thin cast strip manufacturing apparatus.

BRIEF DESCRIPTION OF THE DRAWINGS It is explanatory drawing which shows an example of the manufacturing apparatus of the thin cast piece in embodiment of this invention. FIG. 2 is an enlarged explanatory view of a casting portion of the apparatus for manufacturing thin cast slabs shown in FIG. 1; FIG. 2 is an explanatory view showing a state before starting casting in the apparatus for manufacturing a thin cast piece shown in FIG. 1; FIG. 2 is an explanatory view showing a state at the start of casting in the apparatus for manufacturing thin cast slabs shown in FIG. 1 ; FIG. 2 is an explanatory view showing a state after starting casting in the apparatus for manufacturing thin cast slabs shown in FIG. 1 ;

DETAILED DESCRIPTION OF THE INVENTION A thin cast piece manufacturing method and a thin cast piece manufacturing apparatus according to embodiments of the present invention will be described below with reference to the accompanying drawings. In addition, this invention is not limited to the following embodiment.
Here, in the thin cast strip manufacturing method and the thin cast strip manufacturing apparatus 10 of the present embodiment, molten steel is used as the molten metal, and the thin cast strip 1 made of steel is manufactured. there is
Further, in the present embodiment, the width of the thin cast piece 1 to be manufactured is in the range of 300 mm or more and 2000 mm or less, and the thickness is in the range of 1 mm or more and 5 mm or less.

As shown in FIG. 1, a thin cast strip manufacturing apparatus 10 according to the present embodiment includes a pair of cooling drums 11 (11a, 11b) and a thin cast strip 1 produced below the cooling drums 11. A conveying section 20 is provided for conveying while curving in a substantially horizontal direction.
One cooling drum 11a is a movable drum (refers to the cooling drum on the conveying section 20 side; referred to as one cooling drum in the present invention), and the other cooling drum 11b is a fixed drum. (referred to in the present invention as the other cooling drum). The distance between one cooling drum 11a and the other cooling drum 11b is adjusted by moving one cooling drum 11a toward and away from the other cooling drum 11b.

The conveying unit 20 includes pinch rolls 21, 21 for pinching and conveying the thin cast strip 1 in the vertical direction, conveying rolls 22, 22, a looper 23, and a coiler 24 for winding the thin cast strip 1. there is
Here, the pinch rolls 21, 21 are drive rolls that are driven to rotate, and the transport rolls 22, 22 are driven rolls that rotate as the thin cast strip 1 and the dummy sheet 40 move.

Here, as shown in FIG. 2, the thin cast strip manufacturing apparatus 10 of the present embodiment has side dams (not shown) disposed at the widthwise ends of the pair of cooling drums 11 (11a, 11b). A molten steel pool portion 16 is formed by a pair of cooling drums 11 (11a, 11b) and side weirs.
Moreover, above the pair of cooling drums 11 (11a, 11b), there is a tundish 17 for holding the molten steel 3 supplied to the molten steel pool section 16, and the molten steel 3 is supplied from the tundish 17 to the molten steel pool section 16. A submerged nozzle 18 is arranged.

In this thin cast strip manufacturing apparatus 10, the molten steel 3 is cooled in contact with the cooling drums 11 (11a, 11b) rotating in the rotational direction R, thereby cooling the outer circumference of the cooling drums 11 (11a, 11b). The solidified shells 5, 5 grow on the surface, and the solidified shells 5, 5 respectively formed on the pair of cooling drums 11 (11a, 11b) are crimped to each other at the drum kiss point KP, thereby forming a thin casting having a predetermined thickness. Piece 1 is cast.

Here, in the thin cast strip manufacturing apparatus 10 of the present embodiment, a dummy sheet 40 is arranged between the pair of cooling drums 11 (11a, 11b) before starting casting, as shown in FIG. be done.
One end of the dummy sheet 40 is inserted into the drum kissing point KP, the dummy sheet 40 is bent in the horizontal direction below the cooling drum 11, and the other end 24.
Moreover, it is preferable that the thickness of the dummy sheet 40 is within a range of 0.2 mm or more and 1.0 mm or less. The reason for this is that if the thickness of the dummy sheet 40 is less than 0.2 mm, the strength of the dummy sheet 40 is insufficient, and the dummy sheet 40 is likely to break during transportation. If it exceeds 0 mm, the strength of the dummy sheet 40 increases, so that the difference in strength from the thin cast strip 1 increases, stress concentrates on the joint portion between the dummy sheet 40 and the thin cast strip 1, and breakage may occur. This is because it is likely to occur.

Before starting casting, as shown in FIG. 3, the dummy sheet 40 is arranged vertically downward from the drum kiss point KP.
In the thin cast strip manufacturing apparatus 10 of the present embodiment, as shown in FIG. are arranged.

As shown in FIG. 3, the pressing means 30 is disposed on the side of one of the cooling drums 11a, which are movable drums, and includes a pressing roll 31 that contacts the dummy sheet 40 and a rear end side of the pressing roll 31. and a cover member 32 disposed in.
The pressing means 30 is configured to approach and separate from the dummy sheet 40 from the side of one of the cooling drums 11a serving as moving drums. The cover member 32 is configured to cover the dummy sheet 40 and the conveying section 20 arranged below the one cooling drum 11a.

In addition, it is preferable that the above-described pressing means 30 can adjust the pressing position and pressing amount of the dummy sheet 40 .
In this embodiment, the pressing position of the dummy sheet 40 by the pressing means 30 is preferably within a range of 600 mm or more and 3000 mm or less vertically downward from the height of the axis of the cooling drum 11 .
As for the pressing position of the dummy sheet 40, when the distance vertically downward from the height of the axis of the cooling drum 11 is less than 600 mm, the leaked matter dropped from between the cooling drums 11a and 11b at the start of casting to below the cooling drum 11a. It may collide with the cover member 32, rebound, and collide with or adhere to the surface of the cooling drum 11a. Further, when the distance vertically downward from the height of the axis of the cooling drum 11 exceeds 3000 mm as the pressing position of the dummy sheet 40, the dummy sheet 40 becomes loose between the drum kiss point KP and the pressing position of the cover member 32. becomes large, and the leaked matter that has fallen below the cooling drum 11 at the start of casting may adhere to the slack portion of the dummy sheet 40 .
In addition, considering the angle θ of the dummy sheet 40 with respect to the vertical direction, which is curved so as to be convex toward the cooling drum 11b by the pressing function of the cover member 32, the pressing amount of the dummy sheet 40 by the pressing means 30 is is preferably in the range of 100 mm or more and 600 mm or less in the horizontal direction.

Next, a method for manufacturing a thin cast strip using the thin cast strip manufacturing apparatus 10 of the present embodiment will be described.
First, before starting casting, as shown in FIG. 3, a dummy sheet 40 is inserted between the pair of cooling drums 11 (11a, 11b).
Here, since the cooling drum 11 is provided with a concave crown shape in advance in order to cope with the thermal expansion due to the heat of the molten steel 3 on its outer peripheral surface, the cooling drum 11 (11a, 11b) has a gap between the pair of cooling drums 11 (11a, 11b). Even if the dummy sheet 40 is inserted into the gap, a slight gap is formed.
Therefore, when the molten steel 3 is supplied to the molten steel pool portion 16 formed by the pair of cooling drums 11 (11a, 11b) and the side weir, the molten steel 3 leaks out from the gap between the pair of cooling drums 11 (11a, 11b). Molten spillage may occur.

Therefore, in the present embodiment, at the start of casting (at the start of supplying the molten steel 3 to the molten steel pool portion 16), as shown in FIG. The pressing means 30 presses the dummy sheet 40 from the side of one cooling drum 11a, which is a moving drum, and curves it convexly toward the side of the other cooling drum 11b, which is a fixed drum. Here, it is preferable that the angle θ of the dummy sheet 40 curved to be convex toward the other cooling drum 11b side with respect to the vertical direction is within the range of 5° or more and 45° or less.
The reason for setting the angle θ will be described below. If the angle .theta. is less than 5.degree., the melted and leaked material leaking from the drum kiss point KP to the cooling drum 11a side may drop onto the pressure roll 31 and adhere. The lower limit of the angle θ is more preferably 10° or more, more preferably 15° or more.
If the angle .theta. exceeds 45.degree., the catenary curvature of the dummy sheet 40 becomes excessive, and the bonding between the dummy sheet 40 and the thin cast strip 1 may be impaired. The upper limit of the angle θ is more preferably 40°, more preferably 35°.

In this state, the molten steel 3 is poured from the tundish 17 through the submerged nozzle 18 toward the molten steel pool portion 16 . Then, when the molten steel 3 is supplied to the molten steel pool portion 16, the molten steel 3 leaks out from the gap between the pair of cooling drums 11 (11a, 11b).
At this time, the melted leaking material leaked to one cooling drum 11a falls on the cover member 32 and does not fall on the dummy sheet 40 and the conveying section 20 positioned below the cover member 32. .
Also, the melted leakage material leaked to the other cooling drum 11b falls on the curved dummy sheet 40, slides down on the curved dummy sheet 40, and may stick to the dummy sheet 40. Suppressed.

When the surface of the molten steel 3 in the molten steel pool portion 16 reaches a predetermined position, the pair of cooling drums 11 (11a, 11b) are rotated in the rotational direction R, and the dummy sheet 40 is transferred to the coiler by the conveying portion 20. 24 side. At this time, the pressing roller 31 in contact with the dummy sheet 40 rotates following the movement of the dummy sheet 40, so that the dummy sheet 40 can be moved smoothly.

Then, following the dummy sheet 40, the thin cast strip 1 is pulled out. At this time, since the leakage of the molten steel 3 from between the pair of cooling drums 11 (11a, 11b) is suppressed, as shown in FIG. move on to driving.
The thin cast strip 1 pulled out following the dummy sheet 40 is conveyed by the conveying section 20 and wound up by the coiler 24 . Thus, casting of the thin cast slab 1 is carried out.

According to the thin cast strip manufacturing apparatus 10 and the thin cast strip manufacturing method of the present embodiment configured as described above, when starting to supply the molten steel 3 to the molten steel pool section 16, Pressing means for pressing the dummy sheet 40 located below between the pair of cooling drums 11 (11a, 11b) from the side of one cooling drum 11a and curving it convexly toward the side of the other cooling drum 11b. 30, even if molten leaking material falls from between the pair of cooling drums 11 (11a, 11b) to the other cooling drum 11b side, the molten leaking material slides down along the curved dummy sheet 40. As a result, it is possible to suppress adhesion of melted and leaked matter to the dummy sheet 40 .

Further, the pressing means 30 includes a pressing roll 31 that contacts the dummy sheet 40, and a cover member 32 that is disposed on the rear end side of the pressing roll 31. The dummy sheet is pressed from one cooling drum 11a side. 40, the cover member 32 covers the dummy sheet 40 and the conveying unit 20 on the side of one of the cooling drums 11a. 11a and 11b), it is possible to prevent the melted leaking substance from dropping onto the dummy sheet 40 and the conveying section 20 even when the melted leaking substance falls toward one of the cooling drums 11a.

Therefore, the adherence of the melted and leaked material to the dummy sheet 40 is suppressed at the start of casting, and the thin cast strip 1 can be stably conveyed and wound up. As a result, it is possible to stably start casting a high-quality thin cast slab 1 with few defects.

Further, in the present embodiment, when the angle θ of the dummy sheet 40, which is curved so as to be convex toward the cooling drum 11b side, with respect to the vertical direction is 45° or less, the pair of cooling drums 11 ( 11a and 11b), the melted and leaked material scattered toward the cooling drum 11b can be accurately slid off along the curved dummy sheet 40. - 特許庁
Furthermore, when the angle θ with respect to the vertical direction of the dummy sheet 40, which is curved so as to be convex toward the cooling drum 11b side, is set to 5° or more, the gap between the pair of cooling drums 11 (11a, 11b) is increased. The melted and leaked material that has fallen from the cooling drum 11a side does not accumulate on the pressure roll 31.

In the present embodiment, when the pressing means 30 can adjust the pressing position and pressing amount of the dummy sheet 40, the pressing position and pressing amount of the dummy sheet 40 are adjusted according to the casting conditions. As a result, it is possible to more accurately prevent the melted and leaked material falling from between the pair of cooling drums 11 (11a, 11b) from adhering to the dummy sheet 40. FIG.

Further, in the present embodiment, the pressing position of the dummy sheet 40 by the pressing means 30 is set within a range of 600 mm or more and 3000 mm or less vertically downward from the height of the axis line of the cooling drum 11, and the pressing amount of the dummy sheet 40 by the pressing means 30 is is within the range of 100 mm or more and 600 mm or less in the horizontal direction, the angle θ of the dummy sheet 40 curved so as to be convex toward the other cooling drum 11b side should be optimized with respect to the vertical direction. Thus, it is possible to accurately slide off the melted and leaked material scattered between the pair of cooling drums 11 (11a, 11b) toward the other cooling drum 11b along the curved dummy sheet 40. As shown in FIG.

The apparatus 10 for manufacturing thin cast slabs and the method for manufacturing thin cast slabs, which are embodiments of the present invention, have been specifically described above. It can be changed as appropriate without departing from the idea.
For example, the configuration of the pressing means is not limited to that shown in this embodiment, and the dummy sheet positioned below between the cooling drums is pressed from one cooling drum side and pushed toward the other cooling drum side. Any material can be used as long as it can be curved so as to be convex.

Also, the arrangement of the conveying unit is not limited to the present embodiment, and can be changed in design as appropriate. In addition, it is preferable to dispose a cover member so that the melted and leaked material does not fall on the conveying section.
Furthermore, the configuration of the conveying unit is not limited to that described in this embodiment, and can be appropriately modified in design.

The results of experiments conducted to confirm the effects of the present invention will be described below.
C: 0.05% by mass, Si: 0.15% by mass, Mn: 0.65% by mass, P: 0.01% by mass, S: 0.007% by mass, Al: 0.03% by mass A thin cast slab made of carbon steel was manufactured using the thin cast slab manufacturing apparatus shown in the above-described embodiment.

The manufacturing conditions for thin cast slabs are shown below.
Cooling drum diameter: 1200mm
Casting width: 800mm
Target casting thickness: 3.5 mm
Casting speed: Average 50m/min
Casting atmosphere: Ar+ _N2
Casting amount: 60 tons Dummy sheet: Plate thickness 0.5 mm, made of low carbon steel

In the example of the present invention, as shown in the above-described embodiment, at the start of casting, the cover member pressed the dummy sheet from the moving drum side, and the dummy sheet was curved so as to be convex toward the fixed drum side. The pressing position of the dummy sheet by the pressing means was 1000 mm vertically downward from the height of the axis of the cooling drum, and the pressing amount of the dummy sheet by the pressing means was 300 mm in the horizontal direction.
In the comparative example, the pressing means did not press the dummy sheet at the start of casting.

In the present invention example and the comparative example, casting was performed a plurality of times so that molten steel leakage occurred 50 times each at the start of casting.
In the comparative example, the leaked molten steel adhered to the dummy sheet at the start of casting all 50 times. Seven times out of 50 times, the leaked sticky matter on the dummy sheet got caught in the pinch rolls of the conveying section, and the casting stopped. In addition, 29 out of 50 times, the leaked matter reached the coiler and was caught in it, and the coil winding shape was disturbed. Furthermore, 4 times out of 50 times, the leaked material collided with machinery during transportation, causing damage to the machinery. In the remaining 10 times out of 50 times, although the molten steel adhered to the dummy sheet, casting was completed without disturbance of the coil winding shape or equipment damage.
On the other hand, in the example of the present invention, even when molten steel leaked at the start of casting, there was no trouble in the transfer section, and casting could be started stably.

From the above, according to the example of the present invention, it is possible to prevent the molten material leaking from between the cooling drums from adhering to the dummy sheet at the start of casting, so that the thin cast slab can be stably conveyed and wound up. It has been confirmed that a possible thin-walled cast strip manufacturing method and a thin-walled cast strip manufacturing apparatus can be provided.

1 Thin cast piece 3 Molten steel 10 Thin cast piece manufacturing apparatus 11 Cooling drum 11a One cooling drum 11b The other cooling drum 16 Molten steel pool (molten metal pool)
30 pressing means 32 cover member 40 dummy sheet

Claims (4)

A thin cast slab is manufactured by supplying molten metal to a molten metal pool formed by a pair of rotating cooling drums and a pair of side weirs, and forming and growing a solidified shell on the outer peripheral surface of the cooling drums. A manufacturing method of
At the start of casting, the molten metal is supplied to the molten metal pool while one end of the dummy sheet is inserted between the cooling drums.
Disposing a cover member between one cooling drum and the dummy sheet when supplying the molten metal to the molten metal pool,
The dummy sheet positioned below between the cooling drums is pressed from one cooling drum side by pressing means having a pressing roll disposed at the tip of the cover member, and is projected toward the other cooling drum side. and loosening the dummy sheet between the drum kiss point and the pressing position, thereby suppressing adherence of leaked matter that has fallen downward from between the cooling drums at the start of casting to the dummy sheet. death,
A method for producing a thin cast strip , wherein the pressing means is retreated away from the dummy sheet after the thin cast strip is pulled out . 2. An angle θ with respect to the vertical direction of the dummy sheet curved to be convex toward the other cooling drum side is set within a range of 5° or more and 45° or less. A method for producing thin-walled cast slabs. Thin-walled casting in which molten metal is supplied to a molten metal pool formed by a pair of rotating cooling drums and a pair of side weirs, and a solidified shell is formed and grown on the outer peripheral surface of the cooling drums to produce thin cast slabs. A piece manufacturing apparatus comprising:
At the start of casting, the molten metal is supplied to the molten metal pool while one end of the dummy sheet is inserted between the cooling drums.
A cover member is provided between one of the cooling drums and the dummy sheet to cover leaks that have fallen downward from between the cooling drums at the start of casting when the molten metal is supplied to the molten metal pool portion, and ,
The cover member presses the dummy sheet positioned below between the cooling drums from one of the cooling drums by a pressing roll provided at the tip of the cover member, and pushes the dummy sheet toward the other cooling drum. has a pressing function of curving the dummy sheet into a convex shape and loosening the dummy sheet between the drum kissing point and the pressing position ;
Further, the thin cast strip manufacturing apparatus is characterized in that the cover member has a function of retracting so as to be separated from the dummy sheet after the thin cast strip is pulled out . 4. The apparatus for manufacturing thin cast strips according to claim 3, wherein the pressing function enables adjustment of the pressing position and pressing amount of the dummy sheet.

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