JP6969444B2 - Continuous casting equipment and winding method of casting strip - Google Patents

Description

The present invention relates to a continuous casting facility and a method for winding a cast strip.

In the twin-drum type continuous casting apparatus, for example, as described in Patent Document 1, a pair of cooling drums for continuous casting (hereinafter, also referred to as “cooling drums”) and side dams arranged horizontally facing each other are used to melt metal. A reservoir is formed, and the molten metal stored in the molten metal reservoir is rotated by a pair of cooling drums to cast a thin-walled slab (hereinafter referred to as "casting strip"). When the molten metal is stored in the molten metal storage section, the cooling drums are rotated downward from above, and the molten metal is solidified and grown on the peripheral surface of the cooling drum and sent downward as a cast strip. The cast strips delivered from the cooling drum are horizontally fed by pinch rolls and adjusted to the desired plate thickness by a downstream in-line mill. The cast strip whose thickness has been adjusted by the in-line mill is coiled by a winding device installed downstream of the in-line mill.

In such a twin-drum type continuous casting apparatus, the cooling drum is generally at a low temperature before the start of casting, and when the casting is started, the temperature rises due to contact with the molten metal. Further, the cooling drum is cooled from the inner surface by a cooling medium (for example, cooling water) so as not to exceed a predetermined temperature. Hereinafter, the period during which the temperature of the cooling drum reaches a predetermined temperature and becomes constant is defined as the steady casting period, the arbitrary time point of the steady casting period is defined as the steady casting, and the temperature of the cooling drum during the steady casting period is defined as the steady temperature. .. The state of the steady casting period is called the steady state.

The profile of the cooling drum changes over time from the start of casting to the steady state. Therefore, the profile of the cooling drum is set so that the plate profile (plate crown) of the cast strip at the time of steady casting becomes a desired plate profile.

Further, in such a twin drum type continuous casting apparatus, a dummy sheet is used at the start of casting. The tip of the dummy sheet is set in the coil winding device, and the tail end of the dummy sheet is set so as to be sandwiched between the twin roll drums.

When casting is started, the molten metal at the tip of the casting strip cools and hardens, and is bonded to the tail end of the dummy sheet described above. After that, the casting strip combined with the dummy sheet is sequentially supplied to the casting coil by rotating the cooling drum. The plate thickness of the joint between the cast strip and the dummy sheet is much thicker than the plate thickness of the cast strip. This thick part is also called a hump. If the hump is strongly pressed with a pinch roll or an in-line mill, or if it is rolled, meandering or plate breakage will occur, so this part should be passed through. Since the plate crown fluctuates at the tip of the cast strip, rolling in an in-line mill is started after a steady state to prevent meandering or plate breakage. After the tip of the casting strip passes through the in-line mill, the roll of the in-line mill is rotated to tighten the roll gap and start rolling. This method is called flying touch. Further, in the following, the cast strip until the start of rolling in the in-line mill is referred to as a non-rolled cast strip.

Rolling is not performed on the inline mill from the tip of the casting strip to the completion of the flying touch. Therefore, the winding device located downstream of the rolling device winds the unrolled cast strip at the initial stage of winding the cast strip, and then the rolling of the in-line mill becomes steady and the rolled cast strip has a high temperature. It is rolled up at. When the winding of the cast strip is completed, the coil is cooled by air cooling.

The cast strip that has been wound into a coil is thermally shrunk during the cooling process, and tensile stress is generated. This tensile stress differs depending on the steel type of the cast strip. For example, in high Si steel and the like, the unrolled cast strip is brittle with almost no elongation of the material. In particular, the high Si steel wound at a high temperature cannot withstand the heat shrinkage in the cooling process in the unrolled cast strip portion, and the cast strip may be broken due to tensile stress.

As a method for solving such a problem, for example, in Patent Document 2, a strip-shaped material (glass fiber, alumina fiber, asbestos, etc.) having heat resistance and elasticity at high temperature is used when winding a cast strip. A technique for winding a cast strip by inserting the sheet between the cast strips is disclosed. In Patent Document 2, the strip-shaped sheet serves as a cushioning layer and acts as a cushioning material to alleviate the tension generated in the cast strip and suppress the breakage of the cast strip after winding.

Japanese Unexamined Patent Publication No. 2000-343103 Japanese Unexamined Patent Publication No. 5-138305

However, especially in high Si steel, the winding tension of the coil is increased to wind the cast strip for stabilization during rolling. Therefore, when the strip-shaped sheet described in Patent Document 2 is used, the strip-shaped sheet is already elastically deformed when the cast strip is wound, and the cushioning effect in the cooling step of the cast strip cannot be obtained.

Further, in order to obtain a sufficient cushioning effect with the strip-shaped sheet described in Patent Document 2, the thickness of the strip-shaped sheet needs to be several tens of mm, so that the radius of the cast strip including the strip-shaped sheet after winding is included. Became large and impractical.

Therefore, the present invention has been made in view of the above problems, and a cast strip manufactured by a twin-drum type continuous casting apparatus and wound into a coil shape breaks due to tensile stress due to thermal shrinkage in the cooling process. It is an object of the present invention to provide a new and improved continuous casting facility and a method for winding a cast strip, which can prevent this from occurring, improve the yield, and further reduce the manufacturing cost.

In order to solve the above problems, according to a certain viewpoint of the present invention, a metal molten metal storage portion is formed by a pair of cooling drums and a side dam, and the pair of the cooling drums are rotated and stored in the metal molten metal storage portion. A twin-drum type continuous casting device for casting the molten metal, a rolling device arranged on the downstream side in the casting direction of the twin-drum type continuous casting device, and a rolling device for rolling the cast cast strip, and a rolling device downstream in the rolling direction of the rolling device. A winding device that is arranged on the side and winds a rolled casting strip that is hotter than normal temperature in a coil shape, and a coiled winding device that winds the cast strip that is hotter than normal temperature in a coil shape by the winding device. taken with a, and inclusions supply device for supplying the inclusions so that the material is interposed between the high temperature the cast strip than the normal temperature, the inclusions are ice temperature higher than the room temperature Continuous casting equipment is provided in which the thickness of the inclusions in the radial direction of the coil is reduced between the casting strips.

Further, in order to solve the above problem, according to another viewpoint of the present invention, the metal molten metal storage portion is formed by the pair of cooling drums and the side dams, and the metal molten metal storage is performed while rotating the pair of the cooling drums. A twin-drum type continuous casting device for casting the molten metal stored in the section, a rolling device arranged on the downstream side in the casting direction of the twin-drum type continuous casting device, and a rolling device for rolling the cast cast strip, and the rolling device. A winding device that is arranged on the downstream side in the rolling direction and winds the rolled casting strip having a temperature higher than the normal temperature in a coil shape, and a coil when the casting device having a temperature higher than the normal temperature is wound by the winding device. It is provided with an inclusion supply device for supplying inclusions so that substances are interposed between the cast strips wound in a shape and having a temperature higher than the normal temperature, and the inclusions are at a high temperature of the normal temperature or higher. A continuous casting facility is provided in which the thickness of the inclusions disappears or the thickness of the inclusions in the radial direction of the coil is reduced between the casting strips which are sublimated to a temperature higher than the room temperature.

The inclusions may be dry ice.

The inclusion supply device may supply the inclusions contained in the bag body.

The bag body may be a material that burns when the temperature is higher than normal temperature.

The bag may be a material that does not burn at the temperature between the cast strips wound into a coil.

An exhaust device may be provided for recovering the gas generated from the inclusions or the bag containing the inclusions.

The inclusion supply device may supply the inclusions until at least the tip portion of the casting strip to the flying touch completion portion is wound by the winding device.

Further, in order to solve the above problem, according to another viewpoint of the present invention, the metal molten metal storage portion is formed by the pair of cooling drums and the side dams, and the metal molten metal storage is performed while rotating the pair of the cooling drums. A twin-drum type continuous casting device for casting the molten metal stored in the section, a rolling device arranged on the downstream side in the casting direction of the twin-drum type continuous casting device, and a rolling device for rolling the cast cast strip, and the rolling device. In a continuous casting facility provided with a winding device for winding a rolled casting strip having a temperature higher than normal temperature in a coil shape, which is arranged on the downstream side in the rolling direction, the casting strip having a temperature higher than normal temperature by the winding device is used. A method for winding a casting strip, in which ice is supplied between the casting strips having a temperature higher than the normal temperature as inclusions that disappear or decrease in thickness in the coil radial direction between the casting strips having a temperature higher than the normal temperature during winding. , Is provided. It should be noted that the inclusions, such as dry ice, sublimate when the temperature is higher than the normal temperature, and disappear or decrease in thickness in the coil radial direction between the cast strips having a temperature higher than the normal temperature. May be used.

With the above configuration, when a casting strip having a temperature higher than normal temperature is wound into a coil, inclusions are supplied between the casting strips having a temperature higher than normal temperature, and inclusions disappear between the casting strips having a temperature higher than normal temperature. Alternatively, the thickness of the inclusions in the coil radial direction decreases. Therefore, a space can be provided between the wound cast strips, and breakage due to heat shrinkage can be prevented.

As described above, according to the present invention, in the casting strip manufactured by the twin drum type continuous casting equipment, the unrolled casting strip from the start of casting to the completion of the flying touch breaks in the cooling process after being wound. This can be prevented, the manufacturing cost can be reduced, and the yield can be improved.

It is a conceptual diagram which shows the state of the breakage of a cast strip. It is a figure which showed the state of the breakage of a cast strip. It is a figure which showed the twin drum type continuous casting equipment which concerns on one Embodiment of this invention. It is explanatory drawing which showed the connection part between the tip of the casting strip S and the dummy sheet at the start of rolling which concerns on the same embodiment. It is a figure which showed the modification of the inclusions supply apparatus which concerns on the same embodiment. It is a figure which showed the relationship between the reduction rate by an in-line mill and the breaking elongation at room temperature.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the present specification and the drawings, components having substantially the same functional configuration are designated by the same reference numerals, and duplicate description will be omitted.

(1. Outline of invention)
The present invention relates to a technique for preventing a cast strip, which is cast by a twin-drum type continuous casting apparatus, rolled in an in-line mill, and then wound into a coil shape, from breaking in a cooling process.

Here, first, with reference to FIGS. 1 and 2, a state in which the cast strip wound in a coil shape breaks in the process of cooling will be described. FIG. 1 is a conceptual diagram showing a broken state of a coiled cast strip. Since the cast strip S1 wound up after rolling undergoes thermal shrinkage in the cooling process, tensile stress is generated. The casting strip S2 shows that the casting strip S1 is being cooled, and a broken portion S21 is generated inside the coil. The fracture portion S21 may occur in the unrolled casting strip section from the start of casting to the completion of the flying touch. Due to the characteristics of the material, unrolled cast strips can not withstand heat shrinkage and may break because the material hardly stretches.

When the casting strip is partially broken like the casting strip S2, in the work of rewinding the casting strip in the next step, it is necessary for the operator to manually treat the broken portion of the casting strip, which is an unsteady operation. For this reason, if even a part of the cast strip breaks, the productivity is significantly reduced.

Further, when the fractured portion S21 is generated in the cast strip S2, the fractured portion S31 may be generated up to the outer peripheral portion of the coiled cast strip as in the cast strip S3 due to the impact of the fracture. FIG. 2 shows a state in which the cast strip is completely broken, and in the broken portion S31, it can be seen that the wound cast strip is broken in multiple layers. When the cast strip is completely broken in this way, the cast strip is discarded, which causes a great decrease in yield.

As described above, in the conventional twin-drum type continuous casting apparatus, in the process of winding and cooling the unrolled cast strip from the start of casting to the completion of the flying touch, the cast strip breaks and the manufacturing cost increases. It was rising and the yield was falling.

Therefore, the present inventor has diligently studied a technique for preventing plate breakage in the cooling process of a coiled cast strip. As a result, inclusions that disappear or decrease in coil radial thickness are placed between the casting strips when the temperature between the casting strips is higher than room temperature so that space is created between the wound casting strips. I came up with the idea of supplying. As a result, since a space is provided between the cast strips, a shrinkage allowance for the cast strips due to thermal shrinkage can be secured, and plate breakage can be prevented.

(2. Casting strip manufacturing process)
Next, with reference to FIGS. 3 to 5, the outline of the manufacturing process for manufacturing the cast strip according to the embodiment of the present invention will be described. FIG. 3 is an explanatory diagram showing a schematic configuration of a manufacturing process of a casting strip (thin-walled slab) according to the present embodiment.

As shown in FIG. 3, in the casting strip manufacturing process 1 according to the present embodiment, for example, a tundish T which is a storage device, a twin drum type continuous casting facility 10, an antioxidant device 20, and a cooling device 30 are provided. It includes a first pinch roll device 40, an in-line mill 50, a second pinch roll device 60, a winding device 70, an inclusion supply device 100, and an exhaust device 103.

(Double drum type continuous casting equipment)
As shown in FIG. 3, the twin-drum type continuous casting apparatus 10 includes, for example, a pair of cooling drums 10a and 10b and side weirs (not shown) arranged on both sides of the pair of cooling drums 10a and 10b in the axial direction. And. The pair of cooling drums 10a and 10b and the side weir constitute a molten metal storage unit 15 for storing the molten metal supplied from the tundish T.

The pair of cooling drums 10a and 10b includes a first cooling drum 10a and a second cooling drum 10b. The first cooling drum 10a and the second cooling drum 10b have a concave profile with a slightly recessed center in the axial direction. Further, the first cooling drum 10a and the second cooling drum 10b are configured so that the intervals between the cooling drums 10a and 10b can be adjusted according to the plate thickness or the internal quality of the cast strip to be manufactured. The first cooling drum 10a and the second cooling drum 10b are configured so that a cooling medium (for example, cooling water) can flow inside. The cooling drums 10a and 10b can be cooled by circulating a cooling medium inside the cooling drums 10a and 10b.

In the present embodiment, the first cooling drum 10a and the second cooling drum 10b are set so that, for example, the outer diameter is 800 mm, the drum body length (width) is 1500 mm, and the plate crown of the cast strip in a steady state is 30 μm (initial processing). ) Has been. Needless to say, the outer diameters and drum body lengths (widths) of the pair of cooling drums 10a and 10b are not limited to these.

FIG. 4 is an explanatory diagram showing a connection portion between the tip of the casting strip S and the dummy sheet 11 at the start of rolling. In the twin-drum type continuous casting apparatus 10, as shown in FIG. 4, a dummy sheet 11 is connected to the tip of the casting strip S to start casting. A dummy bar 13 having a thickness thicker than that of the cast strip S is provided at the tip of the dummy sheet 11, and the dummy sheet 11 is guided by the dummy bar 13. Further, a hump 12 thicker than the plate thickness of the casting strip S is formed at the connection portion between the tip of the casting strip S and the dummy sheet 11. In rolling in the in-line mill 50, a rolling start method called a flying touch is performed, in which the hump passes through the in-line mill 50 and then starts rolling. By such a rolling start method, the casting strip S from the tip end portion of the casting strip S to the flying touch completion portion is in a non-rolled state as it is cast.

(Antioxidant device)
The antioxidant device 20 is a device that performs a process for preventing the surface of the casting strip S immediately after casting from being oxidized to generate scale. In the antioxidant device 20, for example, the amount of oxygen can be adjusted by nitrogen gas. The antioxidant device 20 is preferably applied as necessary in consideration of the steel type of the casting strip S to be cast.

(Cooling system)
The cooling device 30 is a device for cooling the cast strip S whose surface has been subjected to the antioxidant treatment by the antioxidant device 20. The cooling device 30 is provided with, for example, a plurality of spray nozzles (not shown), and the cooling water is ejected from the spray nozzles to the surface (upper surface and lower surface) of the casting strip S according to the steel type to form the casting strip S. Cooling.

A pair of feed rolls 87 may be arranged between the antioxidant device 20 and the cooling device 30. The pair of feed rolls 87 sandwich the casting strip S by a reduction device (not shown), and measure the loop length of the casting strip S between the pair of cooling drums 10a and 10b and the feed roll 87. A horizontal transport force is applied to the casting strip S so that the loop length becomes constant. The feed roll 87 is composed of, for example, a pair of rolls having a roll diameter of 200 mm and a roll body length (width) of 2000 mm.

(First pinch roll device)
The first pinch roll device 40 is a pinch roll device arranged on the entry side of the inline mill 50. The first pinch roll device 40 is not shown except for the upper pinch roll 40a and the lower pinch roll 40b, the housing, the roll chock, the rolling load detecting device, and the rolling device (other than the first pinch roll device 40). ) And. The upper pinch roll 40a and the lower pinch roll 40b each have a hollow flow path formed therein, and are configured so that a cooling medium (for example, cooling water) can flow. By circulating the cooling medium, the first pinch roll device 40 can be cooled.

The upper pinch roll 40a and the lower pinch roll 40b may have, for example, a roll diameter of 400 mm and a roll body length (width) of 2000 mm. The upper pinch roll 40a and the lower pinch roll 40b are arranged via a roll chock in the housing and are rotationally driven by a motor (not shown). Further, the upper pinch roll 40a is connected to a pass line adjusting device (not shown) via an upper rolling load detecting device (not shown), and the lower pinch roll 40b is connected to a rolling device (not shown). .) Is connected.

In the first pinch roll device 40 having such a configuration, when the lower pinch roll 40b is pushed up toward the upper pinch roll 40a by the reduction device, the reduction load applied to the upper pinch roll 40a and the lower pinch roll 40b is detected. , Tension is generated in the casting strip S between the first pinch roll device 40 and the straightening device (not shown). Further, the casting strip S in the pair of pinch rolls 40a and 40b and the inline mill 50 so that the tension generated in the casting strip S between the first pinch roll device 40 and the inline mill 50 becomes a preset tension. The moving speed of is controlled. Further, the tension of the casting strip S between the first pinch roll device 40 and the straightening device is detected by the tension roll 88a. A position detecting device 41 for detecting the position of the casting strip S may be provided on the upstream side of the first pinch roll device 40.

(Inline mill)
The in-line mill 50 is a rolling apparatus that rolls the casting strip S to make the casting strip S a desired plate thickness. In the present embodiment, the in-line mill 50 is configured as a 6-stage rolling mill. That is, the inline mill 50 includes a pair of work rolls 51a and 51b, intermediate rolls 52a and 52b arranged above and below the work rolls 51a and 51b, and backup rolls 53a and 53b arranged above and below the intermediate rolls 52a and 52b. And prepare. In this embodiment, for example, work rolls 51a and 51b having a roll diameter of 400 mm, intermediate rolls 52a and 52b having a roll diameter of 450 mm, and backup rolls 53a and 53b having a roll diameter of 1200 mm may be used. The body length of each roll may be the same, for example, 2000 mm.

Further, the in-line mill 50 includes an in-line mill control device for controlling the in-line mill, a plate thickness gauge (neither of them is shown), and the like. The work rolls 51a and 51b are rotationally driven by a motor (not shown) and are cooled by cooling water from the entry side and the exit side. Further, above the backup roll 53a, a hydraulic cylinder (not shown) that presses the backup roll 53a downward is provided.

In the in-line mill 50, after the tip of the casting strip S cast during steady casting passes through the in-line mill 50, the work rolls 51a and 51b of the in-line mill 50 are rotated to tighten the roll gap and start rolling. Such a rolling method is called a flying touch.

Further, the inline mill 50 is controlled by the inline mill control device. The in-line mill control device includes, for example, a mill control unit that controls the in-line mill 50 collectively, a hydraulic cylinder control unit that controls a hydraulic cylinder, an intermediate roll shift control unit, a roll rotation control unit, a roll bending force setting unit, and the like (either Also not shown.) Includes.

The hydraulic cylinder control unit reduces and controls the hydraulic cylinder connected to the backup roll 53a. The hydraulic cylinder control unit controls the hydraulic cylinder and adjusts the roll gap between the work rolls 51a and 51b based on the instruction from the mill control unit that controls the inline mill 50 in a centralized manner. At this time, the mill control unit is a plate in which the casting strip S is preset based on the plate thickness of the casting strip S measured by a plate thickness gauge (not shown) installed on the outlet side of the inline mill 50. Adjust the roll gap so that it is formed thicker. As the plate thickness gauge, for example, an X-ray plate thickness gauge or the like may be used. The intermediate roll shift control unit moves the intermediate rolls 52a and 52b in the roll axis direction, respectively, based on the instruction from the mill control unit. The roll rotation control unit controls the rotation speeds of the work rolls 51a and 51b based on the instruction from the mill control unit. The roll bending setting unit sets the roll bending force for the work rolls 51a and 51b.

(Second pinch roll device)
The second pinch roll device 60 is arranged on the exit side of the inline mill 50. Like the first pinch roll device 40, the second pinch roll device 60 includes an upper pinch roll and a lower pinch roll, a rolling load detecting device, and a rolling device. The upper pinch roll and the lower pinch roll each have a hollow flow path formed therein, and are configured so that a cooling medium (for example, cooling water) can flow. The pinch roll can be cooled by circulating the cooling medium. The upper pinch roll and the lower pinch roll may have, for example, a roll diameter of 400 mm and a roll body length (width) of 2000 mm. Further, the upper pinch roll and the lower pinch roll are arranged via a roll chock in the housing, and are rotationally driven by a motor (not shown). A tension roll 88b is arranged between the in-line mill 50 and the second pinch roll device 60.

(Winling device)
The winding device 70 is a device arranged on the outlet side of the second pinch roll device 60 and winds the rolled cast strip S having a temperature higher than normal temperature into a coil. A deflector-roll 89 is arranged between the second pinch roll device 60 and the take-up device 70.

(Container supply device)
The inclusions supply device 100 is a device that supplies the inclusions D between the casting strips S when the winding device 70 winds the casting strip S having a temperature higher than room temperature in a coil shape. In the present embodiment, as shown in FIG. 3, as an example of the inclusions supply device 100, a device for supplying sheet-shaped inclusions D is shown. The inclusions supply device 100 is arranged in the vicinity of the winding device 70 so that the inclusions D can be supplied immediately before the casting strip S wound on the winding device 70 overlaps with the casting strip S already wound. NS.

The sheet-shaped inclusions D supplied from the inclusion supply device 100 shown in FIG. 3 are, for example, coiled around a non-driven rotating shaft and supplied to the casting strip S wound by the winding device 70. Then, it is wound together with the casting strip S by the rotational drive of the winding device 70. Further, the inclusion supply device 100 may be provided with a braking function (not shown) such as, for example, a powder brake in order to suppress rotation due to inertia of the non-driven rotating shaft. Although not shown, an inclusion guidance device that grabs the tip of the inclusion D of the inclusion supply device 100 and guides the inclusion device 70 to the winding device 70 may be deployed.

The transport line is positioned by the deflector roll 101 so that the sheet-shaped inclusions D supplied from the inclusions supply device 100 are correctly supplied to the casting strip S wound up by the winding device 70. Further, a cutting device 102 for cutting the sheet-shaped inclusions D is provided between the winding device 70 and the deflector roll 101. By providing the cutting device 102, the sheet-shaped inclusions D can be supplied as much as necessary between the cast strips S wound in a coil shape.

The details of the inclusions D will be described later, but the inclusions D may be granular, such as ice, in addition to the sheet shape shown in FIG. In this case, the inclusions D may be supplied by using, for example, the inclusions supply device 100a as shown in FIG. 5 instead of the inclusions supply device 100 shown in FIG. The inclusions supply device 100a is provided with, for example, a hopper for accommodating the inclusions D, and is configured to be able to supply the inclusions D by a predetermined supply amount between the casting strips S from the supply port of the hopper. By changing the supply amount, the thickness of the inclusions in the coil radial direction of the coiled cast strip S can be changed. Further, even if partition plates (not shown) or the like are provided at both ends of the casting strip S so that inclusions D such as granules supplied from the inclusion supply device 100a do not spill from the casting strip S. good.

(Exhaust device)
An exhaust device 103 that collects and discharges the exhaust gas generated when the inclusion D disappears or decreases may be deployed on the upper part of the winding device 70. The exhaust device 103 is composed of, for example, a duct, a pipe, and an exhaust fan, and smoke exhaust enclosed by a hood installed above the winding device 70 is driven by the exhaust fan to pass through the duct and the pipe. Discharge to the outside of the equipment. The exhaust equipment 103 may be provided with a filter or the like for collecting substances contained in the exhaust gas, if necessary.

(3. Types of inclusions)
As the inclusions D supplied between the casting strips S in the present embodiment, a substance that disappears or the thickness of the inclusions in the coil radial direction decreases between the casting strips S having a temperature higher than room temperature is used. The disappearance of the inclusions D or the decrease in the thickness of the inclusions in the radial direction of the coil creates a space between the casting strips S. When the casting strip S is cooled, this space serves as a shrinkage allowance for the casting strip S during thermal shrinkage, so that the casting strip S can be cooled without breaking. The winding temperature of the casting strip S is usually about 800 ° C. to 1000 ° C., and the casting strip S is cooled until it reaches room temperature.

Here, the disappearance of the inclusions D between the casting strips S having a temperature higher than the normal temperature means that the inclusions D supplied by the inclusions supply device 100 naturally disappear with the passage of time in the region where the casting strips S face each other. Say that. With the disappearance of the inclusions D in this way, a space exists between the facing casting strips S. Further, the decrease in the thickness of the inclusions D means that the thickness of the inclusions D decreases in the coil radial direction when the volume of the inclusions D supplied between the casting strips S changes with the passage of time. .. Similar to the disappearance of inclusions D, the reduction in inclusion thickness results in the presence of space between the opposing cast strips S.

First, a case where the thickness of the inclusion D decreases in the radial direction of the coil will be described. As an example of reducing the thickness of inclusions D, inclusions D may be burned, for example, when the temperature between the cast strips is higher than room temperature. By burning the inclusions D, the volume of the inclusions D can be reduced and the thickness of the inclusions D in the coil direction can be reduced. Exhaust gas generated by combustion is discharged to the outside of the system by the exhaust device. The inclusion D may be, for example, paper, bamboo, wood, or a polymeric material. When these objects are used as inclusions D, they can be processed into a sheet shape that can be easily supplied when they are supplied between the casting strips S, which improves convenience.

Further, the inclusions D may be melted when the temperature between the casting strips is a high temperature of room temperature or higher. By melting, the inclusions D change from a solid to a liquid, so that they have fluidity and can be easily removed from between the casting strips S to provide a space between the casting strips S. For example, inclusion D may be ice. When the inclusions D are ice, the change of ice into water reduces the volume, so that a space can be provided between the casting strips S. Further, if the inclusion D is ice, it can be used while suppressing the influence of foreign matter adhering to the surface on the quality of the cast strip S.

Next, the case where the inclusion D disappears will be described. As an example in which inclusions D disappear, for example, inclusions D may be sublimated when the temperature between the cast strips is a high temperature of room temperature or higher. By sublimating the inclusions D, the solid becomes a gas, so that a space can be provided between the casting strips S. Specifically, the inclusion D may be dry ice. The gas generated from the dry ice may be recovered by the exhaust device. By sublimating the inclusions D, it is possible to save the trouble of separately collecting or removing the inclusions D.

(3-1. Shape of inclusions)
The shape of the inclusion D may be, for example, a sheet. By forming the inclusions D in the form of a sheet, the inclusions D can be continuously supplied between the casting strips S. It is desirable that the sheet-like inclusions D have a width comparable to the width of the cast strip S. Further, the sheet-shaped inclusions D may have irregularities, but the thickness thereof is preferably uniform. Thereby, a space having a uniform height in the radial direction can be formed between the cast strips S.

The shape of the inclusion D may be granular. The grain size may be spherical, and the grain size may be about 5 to 6 mm. When the inclusions D are granular in this way, the thickness of the inclusions D interposed between the casting strips S in the coil radial direction can be adjusted by adjusting the inclusion amount. For example, inclusions D may be ice grains or dry ice grains. Further, the inclusion D is not limited to uniform granules and may be in a non-uniform pulverized form. For example, the inclusions may be crushed objects such as scrap plastic pieces. As a result, waste materials and the like can be effectively used.

The granular inclusions D as described above may be contained in a bag and supplied. By being housed in the bag body, it is possible to prevent the inclusions D from being scattered, and it is possible to stably supply the inclusions D to the region where the casting strip S faces. Further, by accommodating and supplying such inclusions D in the bag body, it is possible to prevent the substance contained in the inclusions D from adhering to the cast strip S.

The bag body as described above may be formed from a material that burns when the temperature is higher than normal temperature. Since the volume of the bag body is reduced by burning, more space can be created in the region where the casting strip S faces. The bag body may be, for example, paper or a polymer material.

On the other hand, the bag may be formed of a material that does not burn at the temperature between the cast strips S. Since the inclusions D contained in the bag are not exposed because the bag body does not burn, it is possible to prevent the inclusions D from adhering to the cast strip S. Such a bag can be formed from, for example, a SiO _{2 fiber.} The SiO ₂ fiber has a refractory temperature of about 1000 ° C. and does not burn at the temperature between the casting strips S. As described above, the bag body is not limited to the _{SiO 2} fiber as long as it is a bag body that does not burn at the temperature between the cast strips S.

(3-2. Supply point of inclusions)
Furthermore, the present inventor has also conducted diligent research on which part of the cast strip S needs to be supplied with the inclusion D as described above.

Here, with reference to FIG. 6, the relationship between the fracture of the cast strip S and the reduction rate will be described. FIG. 6 shows the relationship between the rolling reduction of the in-line mill with respect to the casting strip S and the breaking elongation (temperature room temperature) of the rolled casting strip S. This example shows an example of high Si steel in which the cast strip S contains 3% or more of Si. The thickness of the cast strip in FIG. 6 is 2 mm, and the temperature of the cast strip on the in-line mill inlet side is 1000 ° C.

The rolling reduction and plate temperature to be rolled by the in-line mill vary depending on the steel type, quality to be obtained, or material. Especially for high Si steel, when the rolling temperature is 1000 ° C, rolling is performed at a rolling reduction of 25% or more. conduct.

As shown in FIG. 6, as the reduction rate increased, the breaking elongation of the cast strip S at room temperature increased, and when the reduction rate was 25% or more, the increase rate of the breaking elongation tended to slow down. On the other hand, it can be seen that there is almost no fracture elongation in the unrolled cast strip portion where the rolling reduction is not performed by passing through the strip and the rolling reduction ratio is 0%. Therefore, the cast strip S breaks even with a slight heat shrinkage. Therefore, it can be seen that the unrolled cast strip portion from the start of casting to the completion of the flying touch, which is not reduced by through through, is more likely to break due to heat shrinkage in the cooling step than the portion after the completion of the flying touch. From this, it can be said that in order to prevent plate breakage, it is effective to reduce the tensile stress due to thermal shrinkage at least for the unrolled cast strip from the start of casting to the completion of flying touch.

Although not shown, the reduction rate and strength of the cast strip in the in-line mill were almost the same as those shown in FIG. Therefore, the higher the reduction rate in the in-line mill, the higher the strength. Therefore, it was also found that the cast strip S that has been reduced by the in-line mill is less likely to break than the unrolled material that has not been reduced by the in-line mill.

From the above, in the cooling process after winding the casting strip, by supplying inclusions to the unrolled casting strip from at least the start of casting to the completion of the flying touch, the casting strip S is broken due to thermal shrinkage in the cooling process. Can be prevented.

(4. Summary)
The continuous casting equipment according to the present embodiment has been described above. In the continuous casting equipment according to the present embodiment, when the casting strip is wound by the winding device, inclusions disappearing or decreasing in thickness in the coil radial direction are interposed between the casting strips at a temperature higher than normal temperature. .. This prevents the cast strip from breaking during the cooling process. By preventing the cast strip from breaking, it is possible to reduce the manufacturing cost and improve the yield.

Hereinafter, examples of the present invention will be described. This example was carried out in the manufacturing process of a cast strip having the same configuration as that of FIG. 3 or 5. The cast strip used in the examples was a high Si steel containing 3% Si, and had a cast plate thickness of 2 mm and a plate width of 1200 mm. The acceleration rate of the cooling drum from the start of casting was 150 m / min / 30 seconds, and the rotation speed of the cooling drum in the steady state was 150 m / min. For the initial profile of the cooling drum, the initial profile was processed so that the plate crown of the cast strip was 43 μm in a steady state.

Further, the cast strip having a temperature of 1000 ° C. on the inlet side of the inline mill was rolled at a compression rate of 30% of the inline mill, and the plate thickness of the cast strip on the outlet side of the inline mill was set to 1.4 mm. After rolling, inclusions were supplied between the cast strips, and winding was performed with a coiler having an inner diameter of 20 cm with a winding tension of 10 MPa. After winding, cooling was performed by air cooling, and it was investigated whether or not the coil was broken. A take-up sleeve was set in the coiler, the cast strip was wound on the sleeve, and the wound coiled cast strip was taken out for each sleeve and then sent to the next step.

The inclusions were supplied in the range from the tip of the casting strip to the completion of the flying touch until the rolling by the in-line mill was started, and the supply of the inclusions was terminated at the flying touch completion portion.

The rolling in the in-line mill was started 15 seconds after the start of casting, which was after the dummy sheet had passed and the plate crown of the casting strip became 150 μm or less.

In Example 1, a sheet of paper was used as an inclusion. Further, in Examples 2 and 3, polyethylene was used as an inclusion and was contained in a bag and supplied. In Example 2, granular polyethylene having a particle size of 7 mm was housed in a paper bag having a thickness of 0.3 mm. In Example 3, polyethylene having a particle size of 6 mm was housed in a bag made _{of a SiO 2 fiber woven fabric having a thickness of 1.0 mm.} In Example 4, dry ice having a particle size of 6 mm was used as an inclusion. In the comparative example, winding was performed only with the cast strip without supplying inclusions.

First, the first embodiment will be described. In Example 1, papers having a width of 1200 mm having different thicknesses were supplied from the tip of the casting strip to the flying touch completion portion, and the presence or absence of plate breakage was examined. At the flying touch completion section, the supply of inclusions was terminated by cutting the paper.

As a result, it was confirmed that the cast strip did not break when the thickness was 5 mm or more. Further, in the process of winding the cast strip, smoke was generated due to the combustion of paper, but the exhaust treatment was smoothly performed by the exhaust device. From this result, it was found that the average thickness of the inclusions should be at least 5 mm or more.

Next, in Example 2, polyethylene having a particle size of 7 mm was housed in a bag made of 0.3 mm paper and supplied between the tip of the cast strip and the flying touch completion portion. The coil radial thickness of the inclusions supplied between the coiled cast strips was 5 mm.

The cast strip in Example 2 was also cooled to room temperature, but no plate breakage occurred.

In Example 3, polyethylene having a particle size of 6 mm was housed in a bag and supplied between the tip of the cast strip and the flying touch completion portion. The coil radial thickness of the inclusions supplied between the coiled cast strips was 5 mm.

The cast strip in Example 3 was also cooled to room temperature, but the cast strip did not break.

In Example 4, dry ice having a particle size of 6 mm was directly supplied from the tip of the casting strip to the flying touch completion portion without using a bag. The coil radial thickness of the inclusions supplied between the coiled cast strips was 5 mm.

The cast strip in Example 4 was also cooled to room temperature, but the cast strip did not break. When dry ice is supplied as an inclusion as in Example 4, smoke (including water vapor) is present because there is no combustible or the like as compared with the case where paper is supplied as an inclusion as in Example 1. The occurrence of was suppressed.

On the other hand, in the comparative example, the cast strip was wound without supplying inclusions. In the comparative example, when the cast strip was cooled to room temperature, plate breakage occurred inside the coil.

From the above, according to the present invention, in the casting strip manufactured by the twin-drum type continuous casting equipment, the casting strip is broken due to the tensile stress caused by the thermal shrinkage generated in the process of cooling the casting strip wound in a coil shape. It was confirmed that it is possible to improve the yield or reduce the manufacturing cost by preventing the above.

Although the preferred embodiments of the present invention have been described in detail with reference to the accompanying drawings, the present invention is not limited to these examples. It is clear that a person having ordinary knowledge in the field of technology to which the present invention belongs can come up with various modifications or modifications within the scope of the technical ideas described in the claims. , These are also naturally understood to belong to the technical scope of the present invention.

1 Casting strip manufacturing process 10 Twin drum type continuous casting device 10a, 10b Cooling drum 11 Dummy sheet 12 Protrusion part 13 Dummy bar 15 Metal molten metal storage part 20 Antioxidant device 30 Cooling device 40 First pinch roll device 40a, 40b Pinch roll 50 In-line mill 51a, 51b Work roll 52a, 52b Intermediate roll 53a, 53b Backup roll 60 Second pinch roll device 70 Winding device 100 Inclusion supply device 101 Deflector roll 102 Cutting device 103 Exhaust device

Claims (11)

A twin-drum type continuous casting device that forms a metal molten metal storage part by a pair of cooling drums and a side weir, and casts the metal molten metal stored in the metal molten metal storage part while rotating the pair of the cooling drums.
A rolling apparatus arranged on the downstream side in the casting direction of the twin-drum type continuous casting apparatus and rolling the cast casting strip, and a rolling apparatus.
A winding device that is arranged on the downstream side in the rolling direction of the rolling device and that winds a rolled cast strip having a temperature higher than normal temperature into a coil.
Supplied by the winding device, when winding the high temperature cast strip than the ambient temperature, the inclusions so that the material between the high temperature the cast strip than the normal temperature which is wound into a coil is interposed Inclusion supply device and
Equipped with
A continuous casting facility in which the inclusions are ice and disappear or the thickness of the inclusions in the coil radial direction decreases between the casting strips hotter than room temperature. A twin-drum type continuous casting device that forms a metal molten metal storage part by a pair of cooling drums and a side weir, and casts the metal molten metal stored in the metal molten metal storage part while rotating the pair of the cooling drums.
A rolling apparatus arranged on the downstream side in the casting direction of the twin-drum type continuous casting apparatus and rolling the cast casting strip, and a rolling apparatus.
A winding device that is arranged on the downstream side in the rolling direction of the rolling device and that winds a rolled cast strip having a temperature higher than normal temperature into a coil.
When the casting strip having a temperature higher than the normal temperature is wound by the winding device, inclusions are supplied so that a substance is interposed between the casting strips wound in a coil shape and having a temperature higher than the normal temperature. Inclusion supply device and
Equipped with
The inclusions
Sublimates when the temperature is higher than normal temperature ,
A continuous casting facility in which disappearance or the thickness of the inclusions in the coil radial direction is reduced between the cast strips hotter than room temperature. The continuous casting facility according to claim 2 , wherein the inclusions are dry ice. The continuous casting facility according to any one of claims 1 to 3 , wherein the inclusion supply device supplies the inclusions housed in a bag. The continuous casting facility according to claim 4 , wherein the bag body is made of a material that burns when the temperature is higher than room temperature. The continuous casting facility according to claim 4 , wherein the bag body is made of a material that does not burn at the temperature between the casting strips wound in a coil shape. The continuous casting facility according to any one of claims 1 to 6 , further comprising an exhaust device for recovering the inclusions or the gas generated from the bag containing the inclusions. 17. Continuous casting equipment. A twin-drum type continuous casting device that forms a metal molten metal storage part by a pair of cooling drums and a side weir, and casts the metal molten metal stored in the metal molten metal storage part while rotating the pair of the cooling drums.
A rolling apparatus arranged on the downstream side in the casting direction of the twin-drum type continuous casting apparatus and rolling the cast casting strip, and a rolling apparatus.
A winding device that is arranged on the downstream side in the rolling direction of the rolling device and that winds a rolled cast strip having a temperature higher than normal temperature into a coil.
In a continuous casting facility equipped with
When the casting strip having a temperature higher than the normal temperature is wound by the winding device, ice is used as an inclusion that disappears or the thickness decreases in the radial direction of the coil between the casting strips having a temperature higher than the normal temperature. A method of winding cast strips, which is supplied between the cast strips. A twin-drum type continuous casting device that forms a metal molten metal storage part by a pair of cooling drums and a side weir, and casts the metal molten metal stored in the metal molten metal storage part while rotating the pair of the cooling drums.
A rolling apparatus arranged on the downstream side in the casting direction of the twin-drum type continuous casting apparatus and rolling the cast casting strip, and a rolling apparatus.
A winding device that is arranged on the downstream side in the rolling direction of the rolling device and that winds a rolled cast strip having a temperature higher than normal temperature into a coil.
In a continuous casting facility equipped with
When the casting strip having a temperature higher than the normal temperature is wound by the winding device, it sublimates when the temperature is higher than the normal temperature, and disappears or the thickness in the coil radial direction disappears between the casting strips having a temperature higher than the normal temperature. A method for winding a casting strip, in which the reduced inclusions are supplied between the casting strips having a temperature higher than the room temperature. The method for winding a cast strip according to claim 10, wherein the inclusion is dry ice.

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