JP2582952B2 - Metal ribbon continuous casting machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a continuous casting machine for continuously manufacturing a metal strip from a molten metal.

[0002]

2. Description of the Related Art If a metal ribbon can be directly produced from a molten metal,
This is preferable because the rolling process can be greatly simplified. FIG.
Japanese Patent Application Laid-Open No. 61-27675 discloses an example of a twin-drum type metal ribbon continuous casting machine. The molten metal 6 is poured into a basin formed by two rotating drums 18a and 18b rotating in the direction of the arrow. The molten metal in contact with the rotating drum
The solidified shell is cooled from the point m to the point n to form a solidified shell. The solidified shells formed on 18a and 18b are combined at the point n and taken out as the metal ribbon 10. In order to increase the productivity (ton / hour) by this method, the rotating drum must be rapidly rotated.
Due to the short distance between the points, if rotated quickly, the thickness of the solidified shell is insufficient, and a metal ribbon having a predetermined thickness cannot be produced. In addition, if the diameter of the rotating drum is increased, an extremely large-scale facility is required. Further, in this method, the plate thickness can be changed by changing the interval between the rotary drums 18a and 18b. For this purpose, the fixed weir has to be pressed against the drum barrel end. In order to obtain different slabs, it is necessary to prepare drums with various body lengths, equipment costs become enormous, and it is necessary to change drums every time the width of the plate is changed, which is favorable for operation. Not a form.

FIG. 12 shows an example of a twin-belt type metal strip continuous casting machine described in Japanese Patent Application Laid-Open No. 59-47047.
The molten metal 6 is supplied to pulleys 19a, 19 which rotate in the direction of the arrow.
b and 19c, and is poured into a basin formed by an endless belt 1 which runs similarly while stretching and runs. Endless belts 1 and 1 '
Since the back surface is cooled by the cooling devices 12 and 12 ', the molten metal in contact with the endless belt forms a solidified shell, and is taken out as the metal strip 10 which has been substantially solidified. In order to produce a thin metal plate by this method, the distance t between the endless belts 1 and 1 'is reduced. Damages the endless belt and causes
0 is not preferred because the surface properties are impaired.

As described above, the twin-drum type continuous metal strip casting machine can produce thin metal strips, but it is not easy to obtain high productivity and it is not easy to change the sheet width. . On the other hand, the twin-belt continuous strip casting machine
For example, by increasing the distance between 19a and 19b in FIG. 12, high productivity can be obtained, but it is not easy to manufacture a thin metal plate.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a continuous strip metal casting machine capable of producing thin metal strips with high productivity, in which the width of a slab is changed without replacing the components of the casting machine. In addition, the present invention discloses a metal strip continuous caster in which a fixed side weir constituting the short side of a mold has practical durability.

[0006]

FIG. 1 is a schematic front view showing an entire continuous metal strip casting machine to which the present invention is applied. The continuous metal strip casting machine includes an endless belt 1 that is inclined and travels, for example, in a direction indicated by an arrow 5 between an upper roll 2 and a lower roll 3, and is disposed to face the upper belt 2 ′. The long side wall of the upper wide mold is formed by the endless belt 1 'which is inclined with respect to the roll 3' and travels in the direction of arrow 5 ', for example. In the present invention, the endless belts 1 and 1 'are stretched under tension by, for example, tension rolls 9 and 9'. Reference numerals 4 and 4 'denote fixed-side weirs, which are wide-sided along the running path of the endless belts 1 and 1', and are sandwiched between the endless belts to form short side walls of the wide-sided mold. The molten metal 6 is injected into the upper mold, but the endless belt has a cooling pad 1 on the back side.
The solidified shell 8, 8 'is formed in the mold due to the cooling by the solidified shell 8, 8' at the lower end of the mold.
8 ′ are united into a metal ribbon 10. In the continuous strip casting machine of the present invention, since the casting mold has a wide shape, even when casting a thin slab, the injection flow of the molten metal does not directly hit the endless belt. Will not be damaged. When the solidified shells 8 and 8 'are combined, the lower rolls 3 and 3' press the solidified shells via the endless belts 1 and 1 '. The thickness and cross-sectional shape of the metal ribbon 10 are adjusted by this pressing.

FIG. 2 is a plan view of the continuous metal strip casting machine shown in FIG. 1. In order to obtain a slab having a relatively small width, fixed dams 4 and 4 'are inserted into belts 1 and 1'. It is in a state. On the other hand, FIG. 3 shows a state in which a slab having a relatively large width is being cast, and the fixed-side weirs 4, 4 'are located near the end faces of the belts 1, 1'. As described above, in the present casting machine, the plate width can be easily changed by moving the fixed side dams 4 and 4 'in the plate width direction.

In a continuous casting machine having a wide casting mold as the object of the present invention, it is necessary to arrange a fixed side weir on one short side due to its structure. When the solidified shell is generated due to heat deprivation, the solidified shell generated on the side dam when the thickness of the lower part of the pool becomes small is broken due to plastic deformation exceeding the processing limit by the endless belt constituting the long side surface This causes breakouts and quality defects near the end of the slab. In order to avoid such a phenomenon, the molten metal side inner surface of the fixed dam is generally made of a refractory having heat insulation as a main material. However, in this case, a thin slab having a thickness of about 5 mm, for example, is used. In order to manufacture the slab, the width of the lowermost end of the fixed-side weir must be smaller than or equal to the plate thickness, that is, approximately 5 mm, as long as the plate width is variable. However, it is difficult to provide sufficient strength with a side weir having such a small width, and it is also difficult to provide practical durability in terms of wear resistance and spalling resistance.

Therefore, in the fixed weir of the present invention, the wide upper part is mainly made of a refractory material having excellent heat insulating properties, and the narrow lower part is mainly made of a heat conducting material more than the upper part of the side weir. It is made of a good material. With this configuration, it is possible to prevent a solidified shell from being formed at a portion in contact with the fixed-side weir at the upper portion of the pool, and to positively form a solidified shell at the lower portion of the pool. . The solidified shell thus formed at the bottom of the pool also undergoes plastic deformation before reaching the pool exit called the kissing point, but the boundary material where the main material of the fixed dam changes from heat-insulating refractory to thermally conductive material By carefully choosing the position, the plastic deformation experienced by the solidified shell can be kept below the working limit. By forming a solidified shell at the end of the slab at a position above the kissing point as described above, there is no need to arrange a fixed weir up to the kissing point. For example, when casting a slab having a thickness of 5 mm However, the fixed side weir is, for example, 10 mm thick
In this case, casting can be performed without support by the fixed dam up to the kissing point. With this configuration, it is not necessary to make the width of the lowermost end of the fixed-side weir extremely small enough to cause a problem in durability.

FIG. 5 shows an example of the basic structure of the fixed-side weir 4 constructed as described above. The front side of the drawing shows the inside of the fixed side weir on the molten metal side, and the wide upper inner surface of the fixed side weir mainly uses a heat insulating refractory 13 and the narrow lower part mainly uses a material 14 having good heat conductivity. As the refractory 13, for example, zirconia or the like is cited, but this may be sprayed only on the surface layer. As the material 14 having excellent thermal conductivity at the lower portion of the narrow portion, there is also a refractory such as alumina graphite. However, with further emphasis on heat transfer characteristics, for example, the surface of copper is plated with Ni to provide abrasion resistance and the like. What improved the wettability with a molten metal may be used. In any case, it is preferable to provide a heating device mainly used before casting and a cooling device during casting.

Further, in the casting machine according to the present invention , the plate surface shape of the upper wide mold formed by the endless belts 1 and 1 'and the side surface shapes of the corresponding fixed-side dams 4 and 4' are arc-shaped. For this reason, the plate thickness can be changed without replacing the fixed side weir. This will be described in detail below.

FIG. 4 shows a casting machine of the present invention in which the plate surface shape of the upper wide mold of the present invention and the corresponding side surface shape of the fixed dam are arc-shaped, and the plate thickness is larger than that in the state of FIG. The figure shows the case of casting a material, but the endless belt 1
(1 ′), the upper guide roll 2 (2 ′), the lower guide roll 3 (3 ′), and the cooling device 12 (12 ′) integrally rotate rigidly around the center of curvature of the belt surface. As a result, the thickness of the slab can be changed without generating a gap between the slab and the fixed-side weir. Since this casting machine has such a function, it is possible to cast slabs having different thicknesses without replacing the fixed-side weir, and to continuously change the thickness during casting. Is also possible. In general, when the side shape of the fixed weir is a curved shape other than an arc, it is impossible to completely fill the gap between the fixed weir and the fixed weir that occurs at the time of changing the thickness only by rigid rotation or rigid movement of the belt surface,
It does not work as a variable thickness continuous casting machine.

Further, as the side shape of the fixed side weir that can change the thickness without replacing the fixed side weir, there is a linear shape (primary type) in addition to an arc shape (secondary type). In the case of a linear shape, it is not necessary to perform a rigid rotation of the casting apparatus, and the operation of changing the sheet thickness becomes easier, but the belt tension makes it impossible to press the belt against the cooling apparatus. It is difficult to employ pad cooling with high cooling capacity near the meniscus, which increases the risk of belt erosion, and furthermore, the belt also tends to buckle due to temperature deviation, making it difficult to obtain a slab with high plate thickness accuracy. Become. On the other hand, in the case of the arc shape, the belt can be pressed against the cooling device by the belt tension, and pad cooling can be employed over the entire surface, and stable casting can be performed without risk of belt melting. Also, due to the curvature of the belt itself, buckling due to temperature deviation hardly occurs, and a cast piece with high plate thickness accuracy can be obtained.

As described above, by making the shape of the fixed-side weir arc-shaped, it is possible to continuously change the thickness of the slab without replacing the fixed-side weir. It has an industrially very important function of being able to continuously produce a slab of thickness.

FIG. 6 shows the fixed-side weir upper part 13 and the fixed-side weir lower part 1.
4 is shown, but is separated vertically as described above, and, for example, as shown in FIG. 9, by disposing a fixed-side weir moving device 15 that independently controls the position in the slab plate width direction, The optimum position of the fixed-side weir can be set in consideration of the shrinkage of the slab in the sheet width direction, the width expansion of the slab due to the reduction in the thickness direction of the slab, and the like for each casting condition.

FIG. 7 shows an example in which the method of supporting the heat insulating refractory is different from that of FIG. 5 to FIG.
Up to this point, due to the problem of toughness and abrasion resistance of the heat-insulating refractory, a structure in which the heat-insulating refractory is supported by a material having excellent toughness and wear resistance is shown, but as shown in FIG. It is also possible that the upper part of the weir is composed entirely of a heat-insulating refractory.

As described above, it is necessary to prevent the solidified shell from being generated at the upper part of the fixed side weir. However, it is sometimes impossible to prevent the solidified shell from being generated only by employing a refractory having excellent heat insulating properties. is there. In such a case, it is effective to apply minute vibration to the fixed-side weir. If the fixed-side weir moving device 15 in FIG. 9 is of a hydraulic type, minute vibration can be easily applied. In addition, the solidified shell is positively formed in the lower part of the fixed weir, but even in this case, in order to move the solidified shell smoothly together with the belt, it is preferable to apply minute vibration also to the lower part of the fixed weir. At this time,
Since the average solid phase ratio on the pressure receiving surface is significantly different between the upper part of the fixed weir and the lower part of the fixed weir, the optimal values of the frequency and amplitude are different. Preferably, a vibration device is provided.

FIG. 10 is a side view of a continuous strip casting apparatus of the present invention in which gas pressure applying devices 16 and 16 'are arranged below the fixed dam. With such a gas pressure applying device, even at the stage where a thin solidified shell is formed on the end face of the slab, the pressure against the static pressure of the molten metal can be applied by gas, so the fixed side weir is further limited to the upper part Becomes possible,
It is possible to design the fixed-side weir with more margin in terms of durability. In FIG. 10, in order to always supply the gas flows 17, 17 'from a fixed distance from the end face of the slab, the gas pressure applying device 1 is used.
The fixed-side weirs 6 and 16 'are configured to move together with the fixed-side weirs 14 and 14' by means of the fixed-side weir moving devices 15c and 15'c. However, this structure is the lower fixed side weir 14, 1
In the case of the type in which vibration is applied to the 4 'by the moving devices 15c, 15'c, it is not preferable in terms of durability. In such a case, the gas pressure applying device should be provided with a slab width moving device independently.

[0019]

【Example】

Embodiment 1 A belt having a structure as shown in FIG. 1 and having a belt thickness of 1.5 mm, a belt width of 2000 mm, upper guide rolls 2 and 2 ′, lower guide rolls 3 and 3 ′, and cooling devices 12 and 12 ′. Using a casting machine in which the shape of the belt 1 and 1 'is an arc having a radius of curvature of 3000 mm, molten steel having a composition of 0.1% C steel and having a temperature of 1590 ° C is poured into a well and the thickness is 5.0 m.
m, a metal strip having a width of 1500 mm was produced at a casting speed of 98 mpm. At this time, the height of the molten metal surface from the kissing point to the meniscus is 1750 mm, and the contact length between the belt and the basin is about 1940 mm. Initially, the fixed-side weir had a structure in which zirconia was sprayed on the inner surface side of an alumina graphite refractory, and the lower end of the fixed-side weir had a width of 5 mm and the lower end of the fixed-side weir reached the kissing point. However, in this case, shortage of the lower end of the fixed side weir occurred shortly after the start of casting, and an accident occurred in which molten steel leaked from that portion.

Therefore, according to the present invention, the upper portion of the fixed weir has the same structure, and the gap between the belts 1 and 1 'is 100.
The fixed side dam below the position of mm was made of alumina graphite up to the inner surface, and the same casting was carried out using a fixed side weir of 10 mm in width at the bottom end as shown in FIG. Casting was performed smoothly without breakage or leakage of molten steel. Further, under the same conditions, by reducing the distance between the fixed-side weirs 4 and 4 ', the plate thickness is 5.0 mm and the plate width is 90 mm.
A 0 mm slab could be cast. Next, in order to cast a slab having a large thickness, the upper guide roll 2 (2 '), the lower guide roll 3 (3'), and the cooling device 12 (12 ') are integrated with the fixed side weir fixed. Molten steel is injected with the rigid body rotating around the center axis of curvature of the belt surface and the gap at the kissing point expanded to 25 mm, and 5.2 mp
A slab with a thickness of 25 mm could be produced at a casting speed of m.

Embodiment 2 The belt has a structure as shown in FIG. 1 and has a belt thickness of 1.5 mm, a belt width of 2,000 mm, upper guide rolls 2, 2 ', lower guide rolls 3, 3', and cooling devices 12, 12 '. 3. Using a casting machine in which the shape of the belt 1, 1 'thus formed is an arc having a radius of curvature of 3000 mm, molten steel having a composition of 0.1% C steel and having a temperature of 1590 ° C is poured into a basin and has a wall thickness of 3. 6m
m, a metal strip having a width of 1500 mm was produced at a casting speed of 98 mpm. At this time, the height of the molten metal surface from the kissing point to the meniscus is 1750 mm, and the contact length between the belt and the basin is about 1940 mm. Initially, the fixed-side weir had a structure in which zirconia was sprayed on the inner surface side of an alumina graphite refractory, and the lower end of the fixed-side weir had a width of 5 mm and the lower end of the fixed-side weir reached the kissing point. However, in this case, shortage of the lower end of the fixed side weir occurred shortly after the start of casting, and an accident occurred in which molten steel leaked from that portion.

Therefore, according to the present invention, the upper part of the fixed side weir has the same structure, and the gap between the belts 1 and 1 'is 80 mm.
The lower part is made of a copper mold with an inner surface Ni-plated structure, and the lower end width is 12 mm. A fixed side dam having a structure as shown in FIG. 5 is employed and the same casting is performed. Casting was performed smoothly without leakage of molten steel.
Further, by reducing the distance between the fixed dams 4 and 4 'under the same conditions, a slab having a thickness of 5.0 mm and a width of 900 mm could be cast. Next, in order to cast a slab having a large thickness, the upper guide roll 2 is fixed while the fixed side dam is fixed.
(2 '), lower guide roll 3 (3'), cooling device 12
(12 ') as a unit, rigidly rotate around the central axis of curvature of the belt surface to reduce the gap at the kissing point by 2
Molten steel was poured in a state expanded to 5 mm, and a slab having a thickness of 25 mm could be produced at a casting speed of 5.2 mpm.

Example 3 In Example 2, casting was enabled by employing the fixed-side weir according to the present invention, but a thin solidified shell was formed at the upper part of the fixed-side weir and the solidified shell was fixed at the lower part of the fixed-side weir. -A flaw occurred at the end of the slab plate which was presumed to be due to repeated slip. Therefore, the upper fixed side weir and the lower fixed side weir are separated, and the moving device 15 of the fixed side weir as shown in FIG. 9 is hydraulically driven, and the upper fixed side weir has an amplitude of ± 0.5 mm, a frequency of 10 Hz and a lower part. When the fixed dam was subjected to casting with vibration of ± 0.2 mm in amplitude and 20 Hz in frequency, the quality defect at the end of the slab disappeared.

Example 4 In Example 2, casting was possible by employing the fixed-side dam according to the present invention. However, the lower end of the fixed-side dam was considerably worn, and the lower fixed-side dam was replaced by casting with several charges. Needed.
Therefore, as shown in FIG. 10, gas pressure applying devices 16 and 16 'are provided below the fixed side weir, and the lower fixed side weir has a gap from a position of 80 mm to a position of 24 mm. The gas was argon gas, and the pressure in the argon gas pipe was 5 kgf / cm ² so that the same pressure as the molten steel static pressure was applied to the end face of the slab.
And As a result, even when casting a slab having a thickness of 5 mm, it was possible to perform casting smoothly without causing leakage of molten steel, and it was possible to extend the life of the fixed-side weir several times.

[0025]

By using the continuous casting machine of the present invention, it is possible to produce metal strips of various widths and thicknesses stably with good quality and high productivity. Become.

[Brief description of the drawings]

FIG. 1 is a front view showing a basic structure of a continuous metal strip casting machine of the present invention.

FIG. 2 is a plan view showing a state where a slab having a relatively small plate width is being cast by the continuous metal strip casting machine of the present invention.

FIG. 3 is a plan view showing a state where a slab having a relatively large plate width is being cast by the continuous metal strip casting machine of the present invention.

FIG. 4 is a front view of a state in which a slab having a larger thickness than the state of FIG. 1 is being cast by the continuous strip casting machine of the present invention.

FIG. 5 is a diagram of a fixed-side weir employed in the continuous metal strip casting machine of the present invention.

FIG. 6 is a view of a fixed-side weir employed in the continuous strip casting machine of the present invention, which is of a vertical separation type.

FIG. 7 is a view of a still different type of fixed side weir employed in the continuous strip casting machine of the present invention.

FIG. 8 is a diagram of a fixed-side weir employed in the metal strip continuous casting machine of the present invention, in which a wide upper portion has an integral structure.

FIG. 9 is a side view of a cross section of the continuous metal strip casting machine of the present invention cut along a slab plate surface.

FIG. 10 is a side view of a cross section of the continuous metal strip continuous casting machine of the present invention, in which a slab end face below a hot water pool is supported by gas pressure, by a slab plate surface.

FIG. 11 is a view showing a known twin-drum type metal strip continuous caster.

FIG. 12 is a diagram showing a known twin-belt type continuous metal strip continuous casting machine. It is.

[Explanation of symbols]

1,1 'Endless belt 2,2' Upper guide roll 3,3 'Lower guide roll 4,4' Fixed side weir 5 Belt running direction 6 Molten metal 7 Pool 8,8 'Solidified shell 9,9' Tension roll 10 Metal Thin strip 11, 11 'Guide roll 12, 12' Cooling device 13 Upper fixed-side weir made of refractory having excellent heat insulating property 14 Lower fixed-side weir made of refractory having excellent heat insulating property 15 Fixed-side weir moving device 16 Gas Pressure applying device 17 Gas flow 18 Rotary drum 19 Pulley 19 (19a, 19b, 19c, 19a ', 19b',
19c ') Pulley

Claims (4)

(57) [Claims] 1. A pair of endless belts which run while being inclined and run to form a long side surface of an upper mold, and a pair of upper wide mold fixed sides which are sandwiched between the endless belts and form a shorter side of the mold. in metal strip continuous casting machine having a weir, the plate surface of the upper wide template
The shape and the side shape of the corresponding fixed weir are arc-shaped.
Further, the molten metal side at the wide upper portion of the fixed weir is mainly composed of a refractory having excellent heat insulating properties, and the molten metal side at the narrow lower portion of the fixed weir is mainly composed of a material having excellent thermal conductivity. A continuous strip casting machine for a metal strip. 2. The wide upper part and the narrow lower part of the fixed weir are separated.
And each can be moved independently in the width direction of the slab.
The continuous casting machine for a thin metal ribbon according to claim 1, wherein: 3. A metal ribbon continuous casting machine according to claim 1, wherein further comprising a vibrating device on the fixed side dam. 4. A pressure can be applied to the end face of the slab plate.
At the same time, move the gas injection device from the bottom end of
2. The continuous casting machine according to claim 1, wherein the continuous casting machine is disposed at a position up to a gap .