JP6790843B2 - Double roll casting equipment and double roll casting method - Google Patents

Description

The present invention relates to a twin roll casting apparatus and a twin roll casting method for casting slabs.

In continuous casting of metal strips such as aluminum and iron by a twin roll casting device, a pair of horizontally opposed casting rolls are cooled and rotated in opposite directions to supply high temperature molten metal between the casting rolls. Is done.

In the twin roll casting method using the twin roll casting apparatus 10, as shown in FIG. 8, refractory side weirs 12a and 12b are installed at both ends of the rotating casting rolls 11a and 11b, and the casting rolls 11a and 11b and The high-temperature molten metal 5 is stored in the space 13 formed by the side weirs 12a and 12b to form a pool of the molten metal 5. The hot molten metal 5 is housed in the tundish 14 and is supplied from the tundish 14 to the space 13 through the nozzle 15 arranged above the roll gap (reference numeral 17 in FIG. 9). Then, when the molten metal 5 is supplied to the space 13, a solidified shell is formed on the surfaces of the casting rolls 11a and 11b whose inside is cooled in the pool of the molten metal 5. When the solidified shell passes through the roll gap, it is sent out so as to be bonded from both sides by the casting rolls 11a and 11b, so that the solidified shell is taken out as a strip 7 from the roll gap.

The slabs such as strips produced by the twin roll casting apparatus are required to have a thickness and structure as uniform as possible in the width direction. Therefore, a molten metal is applied to the surface of the casting roll by using a nozzle having a slit-shaped or a plurality of openings formed along the rotation axis direction of the casting roll and opening toward the surface of the casting roll. Supply is performed (for example, Patent Documents 1 to 3).

Japanese Unexamined Patent Publication No. 62-282753 Japanese Unexamined Patent Publication No. 9-174209 Japanese Unexamined Patent Publication No. 9-108794 Japanese Unexamined Patent Publication No. 2013-208630

However, when a nozzle as in Patent Documents 1 to 3 is used, when the molten metal 5 is started to be supplied, as shown in FIG. 9, the hot molten metal 5 is transferred from the discharge port 16 of the nozzle 15 to the casting rolls 11a and 11b. It is discharged horizontally to the surface. In a steady state in which a pool of molten metal 5 is formed as shown in FIG. 8, the discharge rate of the molten metal 5 discharged from the nozzle 15 is weakened by the pool, and the hot molten metal 5 is formed on the casting roll 11a. It does not directly collide with the surface of 11b. However, when the supply of the molten metal 5 is started, a hot water pool is not formed, so that the molten metal 5 discharged from the nozzle 15 collides with the surfaces of the casting rolls 11a and 11b as a high-temperature jet. Further, since the casting rolls 11a and 11b are not rotated at the start of supply of the molten metal 5, a high temperature thermal shock is applied to a part of the surfaces of the casting rolls 11a and 11b as shown in FIG.

Further, at the start of supply of the molten metal 5, the molten metal 5 is intensively supplied to the surfaces of the casting rolls 11a and 11b facing the opening of the discharge port 16, so that the molten metal 5 is supplied in the circumferential direction from the kissing point of the casting rolls 11a and 11b. The temperature rises above. Therefore, as shown in FIG. 11, the casting rolls 11a and 11b expand in the rotational axis direction in the circumferential direction above the kissing point, and the refractory side weirs 12a and 12b and the casting rolls 11a and 11b are located near the kissing point. A gap is formed between them.

When the molten metal 5 leaks from this gap, burrs are generated at the ends of the manufactured slab. If the generated burrs are large, the refractory surfaces of the side weirs 12a and 12b will be damaged when the slab moves in the casting direction, leading to further leakage of the molten metal 5, further breaking of the slab and a large amount of burrs. It also leads to the suspension of casting due to leakage of the molten metal 5. In addition, the end faces of the casting rolls 11a and 11b in contact with the side weirs 12a and 12b are also damaged, and the casting rolls 11a and 11b need to be repaired.

For example, in Patent Document 4, as a countermeasure against the generated burrs, a double roll configured to form an opening on the surface of the side weir in contact with the molten metal to generate a small horizontal burr in the width direction of the slab. A formula continuous casting apparatus is disclosed. However, in Patent Document 4, the generation of vertical burrs is suppressed by intentionally generating horizontal burrs that are easy to remove with a burr cutter, and the generation of burrs itself is not suppressed. Therefore, work to remove burrs is necessary.

Therefore, the present invention has been made in view of the above problems, and an object of the present invention is a new and improved double-roll casting apparatus and double-roll casting capable of suppressing the occurrence of burrs. To provide a method.

In order to solve the above problems, according to a certain viewpoint of the present invention, a twin roll casting apparatus for casting slabs, a pair of casting rolls and side dams provided at both ends in the rotation axis direction of the casting rolls. A nozzle that is placed above the roll gap of the casting roll, opens substantially horizontally, and supplies molten metal to the space formed by the casting roll and the side dam from a discharge port formed so as to face the casting roll. A regulation portion for preventing the molten metal discharged from the discharge port of the nozzle from colliding with the casting roll and a discharge direction regulating member having a support portion for supporting the regulation portion are provided, and the regulation portion is a nozzle. In the opening direction of the discharge port, it is formed from a material that is arranged between the discharge port and the casting roll facing the discharge port and has a melting point lower than the melting point of the metal for casting the slab, and the supply of molten metal is started. there is at least until the entire discharge opening of the nozzle is immersed in the molten metal from the time, have a subsequent melting completion thickness, the support portion is formed by restricting part of the same material, the molten metal at steady state provided from the melt surface positioned above, the supporting portion Ru attached to components of the twin roll caster that do not temperature to dissolve, twin-roll casting apparatus is provided.

The surface of the regulation portion facing the discharge port may be arranged so as to be parallel to the rotation axis direction and the vertical direction of the casting roll.

Further, the thickness of the regulated portion may be set so that the melting is completed when the nozzle immersion depth at which the nozzle is immersed in the molten metal reaches the target nozzle immersion depth.

Further, in order to solve the above-mentioned problems, according to another aspect of the present invention, there is provided a double-roll casting method in which a slab is cast using the above-mentioned double-roll casting apparatus.

At this time, a dummy sheet may be used at the start of casting.

As described above, according to the present invention, the generation of burrs can be suppressed. Since the generation of burrs, which was a factor of the occurrence of flaws at the ends of slabs and the drop in yield such as trimming of ends, is suppressed, the casting yield of slabs can be improved and the load of roll maintenance such as casting rolls can be reduced. Can be mitigated.

It is a schematic side view which shows the schematic structure of the twin roll casting apparatus provided with the discharge direction regulation member which concerns on this embodiment, and shows the state at the time of starting the supply of molten metal. It is a top view of FIG. It is a schematic side view which shows the schematic structure of the twin roll casting apparatus provided with the discharge direction regulation member which concerns on this embodiment, and shows a steady state. It is a top view of FIG. It is explanatory drawing for demonstrating the structure of the discharge direction regulation member of the twin roll casting apparatus which concerns on this embodiment. It is explanatory drawing which shows the relationship with the dummy sheet at the time of starting the supply of molten metal in the conventional double roll casting apparatus. It is explanatory drawing which shows the relationship with the dummy sheet at the time of starting the supply of molten metal in the twin roll casting apparatus which concerns on this embodiment. It is a schematic perspective view which shows the structure of the general twin roll casting apparatus. It is explanatory drawing which shows the state at the time of starting the supply of molten metal to a conventional casting roll. FIG. 9 is an explanatory view showing a state in which FIG. 9 is viewed from above. It is explanatory drawing which shows the steady state in which the hot water pool of molten metal is formed in the space formed by a casting roll and a side weir.

Preferred embodiments of the present invention will be described in detail below 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, so that duplicate description will be omitted.

<1. Configuration of twin roll casting equipment>
First, with reference to FIGS. 1 to 4, a schematic configuration of a twin roll casting apparatus including a discharge direction regulating member according to an embodiment of the present invention will be described. FIG. 1 is a schematic side view showing a schematic configuration of a twin roll casting apparatus including a discharge direction regulating member according to the present embodiment, and shows a state at the start of supply of molten metal. FIG. 2 is a plan view of FIG. FIG. 3 is a schematic side view showing a schematic configuration of a twin roll casting apparatus including a discharge direction regulating member according to the present embodiment, and shows a steady state in which a pool of molten metal is formed. FIG. 4 is a plan view of FIG.

The twin roll casting apparatus 100 according to the present embodiment has substantially the same configuration as the general twin roll casting apparatus 10 shown in FIG. 8, and is supplied from a nozzle to a space formed by a casting roll and a side dam. The difference is that a discharge direction regulating member for regulating the discharge direction of the metal is provided. That is, as shown in FIG. 1, the twin roll casting apparatus 100 according to the present embodiment includes a pair of casting rolls 110a and 110b, side weirs 120a and 120b, a nozzle 150, and a discharge direction regulating member 180.

The pair of casting rolls 110a and 110b cool and solidify the supplied molten metal 5 to form a slab. The casting rolls 110a and 110b have a gap of a predetermined size (also referred to as a "roll gap") and are arranged so as to face each other in a substantially horizontal direction. The inside of the casting rolls 110a and 110b is cooled, and the molten metal 5 is cooled to form a solidified shell. Above the roll gaps of the casting rolls 110a and 110b, a nozzle 150 for supplying the molten metal 5 from a tundish (not shown) is arranged. When the supply of the molten metal 5 is started from the nozzle 150, the molten metal 5 is stored in the space formed by the upper surfaces of the casting rolls 110a and 110b and the inner surfaces of the side weirs 120a and 120b, and the molten metal 5 is stored in the hot water pool. To form. The molten metal 5 is stored until the discharge port 160 of the nozzle 150 is immersed in the molten metal 5.

As shown in FIGS. 3 and 4, when the hot water pool of the molten metal 5 is formed and becomes a steady state, the casting rolls 110a and 110b send out the solidified shell formed on the surfaces of the casting rolls 110a and 110b downward. They are rotated so that they rotate in opposite directions. When the solidified shell passes through the roll gap, it is sent out so as to be bonded from both sides by casting rolls 110a and 110b, and is taken out as a strip 7 from the roll gap.

The side weirs 120a and 120b are refractory plate-shaped members that form a pool of molten metal 5 together with the casting rolls 110a and 110b. The side weirs 120a and 120b are provided at both ends of the casting rolls 110a and 110b, and are provided so as to cover between the casting rolls 110a and 110b from the height position of the rotation shaft of the casting rolls 110a and 110b to the upper end. As a result, it is possible to form a space for forming a pool of molten metal 5.

The nozzle 150 supplies the molten metal 5 housed in the tundish (not shown) into the space formed by the casting rolls 110a and 110b and the side weirs 120a and 120b. The nozzle 150 is formed so that the discharge port 160 that opens in a substantially horizontal direction faces the casting rolls 110a and 110b. In the present embodiment, as shown in FIG. 2, the discharge port 160 has four openings 161 to 164 and 165 to 168 formed along the rotation axis direction (Y axis direction) for each of the casting rolls 110a and 110b, respectively. Has been done. This makes it easier to make the thickness of the manufactured slab uniform in the width direction. The shape of the discharge port 160 is not limited to this example, and the number of openings may be other than four, and may be one slit-shaped opening along the rotation axis direction of the casting roll.

The discharge direction regulating member 180 is a molten metal 5 discharged from the discharge port 160 when the supply of the molten metal 5 is started from the nozzle 150 into the space formed by the casting rolls 110a and 110b and the side weirs 120a and 120b. It is a member that regulates the discharge direction. As shown in FIG. 1, the discharge direction regulating member 180 is composed of a pair of regulating members 180a and 180b, and is provided corresponding to each of the casting rolls 110a and 110b. The regulating member 180a includes a support portion 181a for fixing the member to the equipment and a protruding portion 183a protruding from the support portion 181a. Similarly, the regulating member 180b also includes a support portion 181b and a protruding portion 183b. The protruding portions 183a and 183b are arranged at positions separated from the opposing discharge ports 160 (openings 161 to 164 and 165 to 168) by a predetermined distance. The protruding portions 183a and 183b are regulation portions that receive the molten metal 5 discharged from the discharge port 160 and change the direction of the flow.

In the discharge direction regulating member 180, when the molten metal 5 is started to be supplied to the space formed by the casting rolls 110a and 110b and the side weirs 120a and 120b, the molten metal 5 discharged from the discharge port 160 is opened as it is in the discharge port 160. It is provided so as not to flow toward the surfaces of the casting rolls 110a and 110b facing the surface. On the other hand, in a steady state in which a pool of molten metal 5 is formed, it is preferable that the molten metal 5 be supplied to the pool in the horizontal direction in order to prevent inclusions from being mixed into the slab. Therefore, in the present embodiment, the discharge direction regulating member 180 is formed by using a material having a melting point lower than the melting point of the metal for casting the slab. As a result, the protrusions 183a and 183b are present at the start of supply of the molten metal 5 to the casting rolls 110a and 110b, and the protrusions 183a and 183b are present when the height of the molten metal 5 pool is at a predetermined position. Is made to melt, and it is possible to prevent the high-temperature molten metal 5 from colliding with the surfaces of the casting rolls 110a and 110b facing the opening of the discharge port 160 at the start of supply of the molten metal 5. Here, if the surfaces of the protruding portions 183a and 183b facing the discharge ports are arranged so as to be parallel to the rotation axis direction and the vertical direction of the casting roll, the discharge flow at the start of supply of the molten metal 5 is a kissing point. It is desirable because it goes to.

<2. Discharge direction regulating member>
Hereinafter, the configuration of the discharge direction regulating member 180 will be described in more detail with reference to FIG. FIG. 5 is an explanatory diagram for explaining the configuration of the discharge direction regulating member 180 of the twin roll casting apparatus 100 according to the present embodiment.

In the discharge direction regulating member 180, the molten metal 5 discharged from the discharge port 160 is used as a jet flow for a predetermined period from the start of supply of the molten metal 5 to the space formed by the casting rolls 110a and 110b and the side weirs 120a and 120b. It is a member that does not directly collide with the casting rolls 110a and 110b, and is formed in the present embodiment using a material having a melting point lower than the melting point of the metal for casting the slab. It is desirable that the material used for the discharge direction regulating member 180 is similar in composition to the metal to be cast.

Further, the molten metal 5 discharged from the discharge port 160 collides with the protruding portions 183a and 183b of the discharge direction regulating member 180. Therefore, the protruding portions 183a and 183b are preferably formed to have a predetermined thickness so that the molten metal 5 does not easily deform even if it collides with the molten metal 5 and penetrates through the molten metal 5 to disappear. More specifically, the thicknesses of the protrusions 183a and 183b are set to exist at least from the start of supply of the molten metal 5 until the entire discharge port 160 is immersed in the molten metal 5. Here, assuming that the distance from the molten metal surface of the molten metal 5 to the lower end of the nozzle 150 is the nozzle immersion depth, the nozzle 150 is immersed in the molten metal 5 as the molten metal 5 rises. It is desirable that the nozzle immersion depth is set so that melting is completed when the target nozzle immersion depth (hereinafter, also referred to as “target nozzle immersion depth”) is reached.

The target nozzle immersion depth needs to be set to at least the nozzle immersion depth at which the entire discharge port 160 is immersed in the molten metal 5. Under this condition, the shallower the nozzle immersion depth is set, the shorter the time it takes for the discharge flow to move downward, so that inclusions are suppressed from being mixed into the slab. However, on the other hand, if the nozzle immersion depth is set too shallow, the possibility that the protrusions 183a and 183b are completely melted before the entire discharge port 160 is immersed in the molten metal 5 during operation increases. Therefore, it is preferable to examine the range of the nozzle immersion depth in which the protrusions 183a and 183b do not complete the melting before the entire discharge port 160 is immersed in the molten metal 5, and set the target nozzle immersion depth. As the target nozzle immersion depth is set deeper, the time from the start of supply of the molten metal 5 to the target nozzle immersion depth becomes longer, so that the thickness w of the protrusions 183a and 183b is set thicker.

The thickness w of the protruding portions 183a and 183b is usually about 10 to 30 mm. Further, the discharge direction regulating member 180 may be formed by bundling thin plates. If the target nozzle immersion depth is set shallower than the nozzle immersion depth in the steady state, the molten metal level of the molten metal 5 rises until the molten metal 5 reaches the steady state even after the protrusions 183a and 183b have been melted.

For example, for the protrusions 183a and 183b, it is assumed that the initial temperature is room temperature (for example, 300K), one side is a heat insulating condition, and the other side is a temperature condition of the molten metal 5 to be supplied. Then, the density, specific heat, thermal conductivity, and latent heat of melting are given to the protrusions 183a and 183b to perform unsteady heat transfer calculation, and the time when all of the protrusions 183a and 183b become above the solidus temperature is calculated. Although the complete melting condition is the liquidus temperature, the injection flow may penetrate even in the solid-liquid coexisting region, so the time for the temperature to reach the solidus temperature or higher is calculated for safety. Then, the thickness required for the protrusions 183a and 183b can be determined by comparing the calculated time with the time for the molten metal 5 to reach the molten metal surface position in the steady state under the set operating conditions. it can.

The protrusions 183a and 183b are supported until the protrusions 183a and 183b are melted so that the protrusions 183a and 183b do not deform and the discharge flow from the discharge port 160 becomes a desired downward flow. It is desirable to strengthen the support structures of the support portions 181a and 181b to suppress deformation. The support portions 181a and 181b may be formed of the same material as the protrusions 183a and 183b, but in this case, the support portions 181a and 181b are provided above the molten metal surface position of the molten metal 5 in a steady state. Further, when the support portions 181a and 181b are made of the same material as the protrusions 183a and 183b, for example, when the support portions 181a and 181b are fixed to the nozzle 150, the molten metal 5 flows through the nozzle 150 and the temperature is high. Therefore, there is a possibility that the support portions 181a and 181b will melt. Therefore, as shown in FIG. 5, for example, the support portions 181a and 181b are preferably attached to the constituent members of the twin roll casting apparatus 100 that does not become hot enough to melt the support portions 181a and 181b. As a member for attaching the support portions 181a and 181b, for example, a support member 191 for supporting the scum weir 190 inserted into the hot water pool of the molten metal 5, another support member 193, and the like can be used.

Further, as shown in FIG. 5, the lower ends of the protruding portions 183a and 183b of the discharge direction regulating member 180 are provided so as to be located below the lower ends of the discharge port 160. If the lower ends of the protrusions 183a and 183b are above the position L of the lower end of the discharge port 160, the discharge flow of the molten metal 5 from the discharge port 160 slips through the protrusions 183a and 183b, and the opening of the discharge port 160 The high-temperature molten metal 5 collides with the surfaces of the facing casting rolls 110a and 110b. Therefore, the local temperature rise of the casting rolls 110a and 110b cannot be sufficiently suppressed, and the casting rolls 110a and 110b may expand in the rotational axis direction in the circumferential direction above the kissing point. Therefore, it is preferable that the lower ends of the protruding portions 183a and 183b of the discharge direction regulating member 180 are provided so as to be located below the lower ends of the discharge port 160.

The distance d between the discharge direction regulating member 180 and the casting rolls 110a and 110b is not particularly limited, but at least the discharge direction regulating member 180 and the casting rolls 110a and 110b need to be prevented from contacting each other.

By using the twin roll casting apparatus 100 according to the present embodiment, local heating of the casting rolls 110a and 110b at the start of supply of the molten metal 5 is suppressed.

Here, in double-roll casting, a thin plate called a dummy sheet is arranged at the start of casting for the convenience of winding up the slab after casting. FIG. 6 shows the arrangement of the dummy sheets 19a and 19b in the conventional twin roll casting apparatus and the state at the start of supply of the molten metal 5. As shown in FIG. 6, the dummy sheets 19a and 19b are arranged along the casting rolls 11a and 11b above the kissing point, and the molten metal 5 is combined with the solidified shell to guide the casting. The dummy sheets 19a and 19b also serve as a coolant, and also have a function of preventing the molten metal 5 from directly colliding with the roll. The roll temperature near the kissing point where the dummy sheets 19a and 19b are provided is lower than that of the other portions because the temperature rise is suppressed even if the molten metal 5 collides. Therefore, if there is a portion where the molten metal 5 contacts the dummy sheets 19a and 19b and a portion where the molten metal 5 comes into direct contact with the casting rolls 11a and 11b as shown in FIG. 6, the casting rolls 11a and 11b expand in the rotation axis direction. May become more prominent.

Therefore, the dummy sheets 19a and 19b are provided further upward so that the molten metal 5 does not come into direct contact with the casting rolls 11a and 11b above the dummy sheets 19a and 19b as shown in FIG. 6, and the casting rolls 11a , It is also conceivable to suppress the local heating of 11b. However, when the dummy sheets 19a and 19b are provided longer than the kissing points of the casting rolls 11a and 11b in the circumferential direction, the solidified layer formed by solidifying the molten metal 5 that collides with the dummy sheets 19a and 19b is the dummy sheet 19a. , 19b is even thicker than when it is not provided. Therefore, when casting is started after that, when the thick solidified layer passes through the kissing point, the roll gap between the casting rolls 11a and 11b is greatly widened, which leads to a casting trouble at the start of casting. Therefore, the dummy sheets 19a and 19b cannot be extended upward, and it is unavoidable that the molten metal 5 discharged from the discharge port directly hits the casting rolls 11a and 11b.

Even if the dummy sheets 19a and 19b that function as coolants are arranged in this way, the discharge flow of the molten metal 5 directly hits the surfaces of the casting rolls 11a and 11b facing the opening of the discharge port, so that the casting rolls 11a and 11b 11b is locally heated above the kissing point in the circumferential direction and expands in the rotation axis direction. Then, the side weirs 12a and 12b pressed against the casting rolls 11a and 11b at a constant pressure are expanded, and a steady gap is formed between the casting rolls 11a and 11b and the side weirs 12a and 12b near the kissing point. Will occur. Therefore, as the supply of the molten metal 5 progresses, a part of the molten metal 5 infiltrates into the gap between the casting rolls 11a and 11b and the side weirs 12a and 12b, and becomes burrs on the slab.

On the other hand, in the twin roll casting apparatus according to the present embodiment shown in FIG. 7, since the discharge direction regulating member 180 is provided, the flow of the molten metal 5 at the start of supply is caused by the protrusion 183a of the discharge direction regulating member 180. , 183b and is directed downwards. As a result, the molten metal 5 can be dropped on the dummy sheets 195a and 195b installed on the casting rolls 110a and 110b, and the molten metal 5 can be dropped without extending the dummy sheets 195a and 195b in the circumferential direction. Can prevent the casting rolls 110a and 110b from hitting directly. Since the dummy sheets 195a and 195b also function as a coolant, the local temperature rise of the casting rolls 110a and 110b is prevented, and the expansion in the rotation axis direction is suppressed. Therefore, the molten metal 5 does not leak from the gap between the casting rolls 110a and 110b and the side weirs 120a and 120b, and the generation of burrs can be suppressed.

Further, conventionally, as shown in FIG. 9, the molten metal 5 discharged to the surfaces of the casting rolls 11a and 11b spreads upward on the surfaces of the casting rolls 11a and 11b with almost no spread in the rotation axis direction. Was there. Therefore, cooling by the casting rolls 11a and 11b forms a thick solidified layer at the center of the casting rolls 11a and 11b in the rotation axis direction. When the rotation of the casting rolls 11a and 11b starts from such a state when the casting is started, the solidified layer formed in the central portion of the casting rolls 11a and 11b in the rotation axis direction moves downward, and the roll gaps of the casting rolls 11a and 11b Pass through 17. At this time, the roll gap 17 is temporarily widened, which leads to a casting trouble at the start of casting. On the other hand, in the twin roll casting apparatus according to the present embodiment shown in FIG. 7, by providing the discharge direction regulating member 180, it is possible to prevent the supplied molten metal 5 from spreading upward along the surfaces of the casting rolls 110a and 110b. Therefore, it is possible to suppress the occurrence of casting trouble at the start of casting.

As an example, the state of burr generation of the slab when the twin roll casting apparatus provided with the discharge direction regulating member of the present invention was used was verified.

In this example, in a twin roll casting apparatus provided with a casting roll having a width of 400 mm and a diameter of 600 mm, a slab having a casting speed of 0.9 m / s and a thickness of 1.5 mm was cast at a contact arc angle of 45 °. The molten metal was supplied to the casting roll using a flat nozzle having an outer thickness of 30 mm. The flat nozzle had an inner thickness of 20 mm, an inner width of 170 mm, and an internal capacity of 4.2 L, and the immersion depth at the center of the discharge port with respect to the hot water surface of the hot water pool in a steady state was 25 mm. The flat nozzle has a slit-shaped discharge port, and the opening of the discharge port is arranged so as to correspond to the casting roll. The dimensions of the discharge port are 8 mm in height and 170 mm in width, and there are columns with a width of 10 mm for ensuring strength so that the slit widths are evenly spaced at two locations in the width direction. Then, in the opening direction of the discharge port, a discharge direction regulating member is arranged between the discharge port and the casting roll. The discharge direction regulating member is a steel plate containing C: 1.00% by mass, Mn: 0.45% by mass, P: 0.023% by mass, and S: 0.038% by mass (liquidus temperature 1470 ° C., solid). It was formed from a phase line temperature of 1450 ° C.).

The molten metal is a steel (liquid phase) containing C: 0.25% by mass, Si: 0.35% by mass, Mn: 0.90% by mass, P: 0.040% by mass, and S: 0.006% by mass. The wire temperature is 1520 ° C and the solidus wire temperature is 1500 ° C), and the molten metal at a temperature of 1600 ° C before the start of supply is stored at a depth of 300 mm in the tundish provided above the flat nozzle. The stopper for setting the communication state with and was set to correspond to the fully open state, and the supply of molten metal to the casting roll was started. At this time, molten metal was injected from the tundish into the nozzle via a tuyere nozzle having a diameter of 40 mm. The flow rate of the molten metal at this time was 3 L / s. The molten metal surface in the steady state was 210 mm above the kissing point of the casting roll, and the volume of the pool was 4.8 L. That is, since the total volume of the nozzle and the volume of the hot water pool is 9 L and the injection speed is 3 L / s, it is a condition to reach the molten metal surface position in the steady state in about 3 seconds. The thickness of the protruding portion of the discharge direction regulating member was calculated in advance by the above calculation and set to 3 mm.

As a comparative example, the occurrence of burrs on the slabs cast by using a conventional double-roll casting apparatus not provided with a discharge direction regulating member was verified.

When the state of burr generation was verified for the cast slab 50 mm, first, as a comparative example, a maximum of 2 mm was found for a slab cast using a conventional double-roll casting apparatus not provided with a discharge direction regulating member. , An average of 0.5 mm burrs were generated. On the other hand, in the slab produced by the twin roll casting apparatus provided with the discharge direction regulating member of the present invention, the maximum burr was 0.2 mm and the average was less than 0.1 mm. From the above, it can be seen that the generation of burrs is suppressed by using the twin roll casting apparatus provided with the discharge direction regulating member of the present invention. From this, it is expected that the casting yield of the slab can be improved and the load of roll maintenance of the casting roll or the like can be reduced.

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 such 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.

5 Molten metal 7 Strip 13 Space 14 Tundish 100 Twin roll casting equipment 110a, 110b Casting roll 120a, 120b Side weir 150 Nozzle 160 Discharge port 161-168 Opening 180 Discharge direction regulating member 180a, 180b Regulatoring member 181a, 181b Support 183a, 183b Projection 190 Scum weir 191, 193 Support member 195a, 195b Dummy sheet

Claims (5)

A twin-roll casting device that casts slabs.
A pair of casting rolls and
Side weirs provided at both ends in the direction of rotation of the casting roll,
The molten metal is supplied to the space formed by the casting roll and the side weir from a discharge port which is arranged above the roll gap of the casting roll, opens substantially horizontally, and is formed so as to face the casting roll. With the nozzle
A discharge direction regulating member having a regulation portion for preventing the molten metal discharged from the discharge port of the nozzle from colliding with the casting roll and a support portion for supporting the regulation portion .
With
The restricted portion is arranged between the discharge port and the casting roll facing the discharge port in the opening direction of the discharge port of the nozzle, and has a melting point lower than the melting point of the metal for casting the slab. is formed from a material, until said entire outlet of the nozzle to the molten metal from the start the supply of the molten metal is immersed is at least present, have a subsequent melting completion thickness,
The support portion is formed of the same material as the regulation portion, is provided above the molten metal surface position in a steady state, and is a component member of the twin roll casting apparatus that does not reach a temperature at which the support portion melts. attached to Ru, twin roll caster. The twin roll casting apparatus according to claim 1, wherein the surface of the restricted portion facing the discharge port is arranged so as to be parallel to the rotation axis direction and the vertical direction of the casting roll. The thickness of the regulated portion is set according to claim 1 or 2, wherein the melting is completed when the nozzle immersion depth at which the nozzle is immersed in the molten metal reaches the target nozzle immersion depth. The twin roll casting apparatus described. A double-roll casting method in which a slab is cast using the double-roll casting apparatus according to any one of claims 1 to 3. The double roll casting method according to claim 4, wherein a dummy sheet is used at the start of casting.

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