JPH1177252A - Side weir in roll type side pouring continuous casting apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a roll type side pouring continuous casting apparatus which can easily change side weir body and surely prevent the development of a stuck shell and stably cast without the insertion or leakage of molten metal. SOLUTION: In the side weir in the roll type side pouring continuous casting apparatus which is set by press-adhering to the rolls and forms molten metal pool part introduced to the rolls, the side weir body 11 and a heater unit 19 for heating the side weir body 11 from the back surface side, are separately formed and have the constitution combining both so as to be freely attached/ detached. Further, a ceramic sliding body 13 is provided to the sliding part between the side weir body 11 and the rolls.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a side weir of a roll-type horizontal casting continuous casting apparatus configured to continuously cast by a single roll method or a twin roll method.

[0002]

2. Description of the Related Art A cooling roll is used to remove 1 to
There is a casting method for continuously producing thin cast pieces having a thickness of about 10 mm. This casting method can be broadly classified into a vertical pouring type in which a solidification process proceeds in a vertical direction from casting, and a horizontal pouring type in which a solidification process proceeds in a horizontal direction.

In the vertical pouring method, a pair of cooling rolls are horizontally arranged at a predetermined interval, and a side dam is laterally pressed against the roll end face to form a pool. Then, by rotating the pair of rolls in opposite directions, the metal sheet rapidly solidified on the rolls is continuously cast downward.

[0004] The horizontal pouring type includes a twin roll type using a pair of upper and lower rolls and a single roll type using only a lower roll. In both types, the type of hot-water pool is different from the vertical pouring type. In other words, in the twin-roll system, the basin is formed by the circumferential surface of the lower roll in the body length direction, the circumferential surface in the radial direction, and the end surface of the upper roll. On the other hand, in the case of a single roll, it is formed by the two members.

[0005] A nozzle for forming a horizontal pouring type water pool is as follows.
In general, the lower roll is divided into a bottom nozzle that seals the circumferential surface of the lower roll in the axial direction and a side nozzle (side weir) that seals the circumferential surface of the lower roll in the radial direction. In the twin roll method, the side nozzle also seals the upper roll end face. The molten metal is rapidly solidified by a lower roll or upper and lower rolls, and is continuously extruded in a horizontal direction as a thin metal plate.

[0006] In these casting methods, the metal is cooled and solidified on the roll surface. At that time, in order to perform stable casting, it is necessary to prevent the solidified shell of the metal from sticking to the side weir portion.

In order to prevent the shell from sticking to the side weir,
In the vertical pouring method, a method of preheating the side weir is adopted.

For example, Japanese Utility Model Publication No. 3-44363 and
Japanese Patent Publication No. 207555 discloses a method of preheating a side weir by a heater embedded in a base member of the side weir. In this side weir, a heat insulating material is embedded in a side weir case composed of a frame plate and a bottom plate, a base member is planted in the heat insulating material, a heater and a ceramic layer are planted in a base member, and the ceramic layer is rolled on an end face. To directly seal the molten metal.

Further, Japanese Utility Model Application Laid-Open No. 63-150741 and Japanese Patent Application Laid-Open No. 7-68352 disclose the use of corundum or high alumina as a base member.

[0010]

However, in the above-mentioned conventional type side weir, a side weir case, heat insulating material,
The base member, the heater, and the ceramic layer are firmly fixed integrally. Therefore, by sliding with the roll,
When the ceramic layer is worn, the base member is damaged by the molten metal, or when the side weir is replaced every trial of the casting schedule, all of these sets must be replaced.

As described above, the side weir is pressed against the roll end face by the pressing device connected to the case to seal the molten steel. For this reason, in order to replace the complete set, it is necessary to always disassemble and assemble this connecting portion, which has been a great hindrance to operation.

Further, the lateral weir type side weir has a more complicated shape than the vertical pouring type weir.

That is, the lower roll peripheral surface of the side weir contacts and slides with a sliding material (ceramic layer) implanted in the side weir base member, but at a fixed distance from the base member, the heat insulating layer, and the case. It becomes the structure which kept. Therefore, the lower part of the side weir needs to have an R shape along the lower roll peripheral surface or a polygon close to this, and the tip (kiss point side) is, for example, tapered.

Therefore, in the vertical pouring method, for example,
As seen in 3-150741, the heater can be arranged to heat the entire basin. However, in the horizontal pouring method, it was difficult to arrange heaters uniformly on the entire side weir due to the limitation of the installation space.

[0015] Therefore, in the side pouring type weir, the portion where the generation of the solidified shell is most likely to be prevented cannot be sufficiently heated.

An object of the present invention is to solve the above-mentioned problems of the prior art, to easily replace the side dam body, to reliably prevent the formation of a sticking shell, and to realize a stable operation of a roll type. An object of the present invention is to provide a horizontal casting continuous casting apparatus.

[0017]

SUMMARY OF THE INVENTION The present invention relates to a side weir for a roll-type horizontal casting continuous casting apparatus for forming a pool of molten metal which is installed by being pressed against a roll and led to the roll. (11) and a heater unit (19) for heating the side weir body (11) from the back side are formed separately, and the two are configured to be detachably assembled. The gimbal is a side weir of a roll-type horizontal pouring continuous casting apparatus characterized in that a ceramic sliding body (13) is provided in the sliding portion of (1).

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The side weir of the present invention is a roll-type horizontal pouring continuous casting apparatus for continuously casting a thin cast slab by a single roll or twin roll method, and a side weir body and a heater unit for heating the side weir from the back. Are formed separately, and both are detachably assembled.

With such a configuration, only the side weir main body can be easily replaced, and the drawbacks of the integral type conventional side weir can be solved.

The side dam body and the heater unit can be housed in a water-cooled metal case that has been heat-insulated.

In addition, the problem peculiar to the horizontal pouring method that the preheating cannot be sufficiently performed can be solved by using alumina-graphite or graphite refractory having high thermal conductivity.

Further, the heat insulating material of the fixed portion of the side weir main body is
It is preferable to use a material that is harder (higher in strength) than the other heat insulating layers. The dimensional change can be reduced by minimizing the positional error based on this, and absorbing the thermal expansion of the side weir main body due to preheating in the direction opposite to the sliding portion of the lower roll via the spring member.

[0023]

Embodiments of the present invention will be described below in detail.

FIG. 1 is a front view showing an embodiment of a side weir of a twin-roll horizontal casting type continuous casting apparatus of the present invention, FIG. 2 is a view showing a state where only the side weir main body is removed from FIG. 1, and FIG. FIG. 2 is a sectional view taken along line AA of FIG. 1. FIG. 6 is a perspective view showing the outer shapes of a bottom nozzle and side weirs (nozzles).

The continuous casting apparatus has an upper roll 3 and a lower roll 4. Bottom nozzle 1 for upper and lower rolls 3, 4
Are arranged from the left side in FIG. 1, and the side dam main body 11 is assembled so as to sandwich both side surfaces of the bottom nozzle 1.

The sliding portion between the side weir main body 11 and the upper roll end face and the sliding portion between the side weir 11 and the lower roll 4 include:
A ceramic sliding body 13 is embedded and bonded.

On the back side of the side weir body 11, a unitized heater unit 19 is provided.

The side weir body 11 and the heater unit 19 for heating it are arranged in the side weir case 12 provided with a water cooling device as required.

In the case 12, a heat insulating material 15 made of an amorphous refractory is applied, and a heater 34 such as a box 34 and molybdenum disilicide is installed inside the case, thereby forming a heater unit 19. The size of the portion where the heater unit can be accommodated may be made slightly larger than the heater unit, and this gap may be fixed by filling with ceramic fiber felt or the like.

The side weir main body 11 is brought into close contact with the a surface, the a surface, and the c surface of the hard heat insulating material installed inside the side weir case 12 so as not to apply a load to the heater 14, and the upper and lower sides (FIG. (Right side) is fixed via a disc spring 17 (spring).

The box 34 and the heater 14
It is easily inserted and removed inside.

A hard heat insulating layer 15a is disposed on the side weir main body side, and a low heat conductive heat insulating layer 15b is disposed on the opposite side (see FIG. 3).

As described above, the side weir of the present invention is configured such that the heater unit 19 and the side weir main body 11 are formed separately, and both are detachably incorporated in the side weir case 12. Therefore, in the present invention, only the side dam main body 11 can be replaced, and the operation time can be greatly reduced.

Further, in the present invention, since the heater unit 19 and the side weir main body 11 are divided, the heater itself is hardly damaged, and the life can be greatly extended.

In the present invention, the side dam main body 11 is heated by the heater 14 disposed on the back surface thereof. The ceramic sliding body 13 also needs to be preheated, but the portion that is effectively heated by the heater 14 is only the molten steel contact start side 21 (see FIG. 1) of the upper roll. As shown in FIG. 3, the heating effect is hardly obtained between the bottom nozzle tip 22 and the kiss point side 23 because the hard heat insulating layer 15a having the thickness d is interposed therebetween.

Therefore, when the corrugated material or high alumina material is used for the main body of the side dam as in Japanese Utility Model Application Laid-Open No. 63-150741 or Japanese Patent Application Laid-Open No. 7-68352, the thermal conductivity is small and sufficient preheating cannot be performed. For this reason, the side dam main body 11 of the present invention is made of a material having high thermal conductivity.

The alumina-graphite refractory forming the side weir main body 11 is required to obtain sufficient thermal shock resistance and corrosion resistance.
It is preferable to contain 30 to 60% by weight of alumina, 20 to 50% by weight of graphite, and 10 to 30% by weight of silica.

When the amount of alumina exceeds 60% by weight, the amount of graphite is less than 20% by weight, and the amount of silica is less than 10% by weight, sufficient thermal shock resistance cannot be obtained. In addition, when the amount of alumina is less than 30% by weight, the amount of graphite exceeds 50% by weight, and the amount of silica exceeds 30% by weight, the corrosion resistance becomes insufficient.

The thermal conductivity of alumina graphite is 15 W / m
-It is preferable that it is K or more. Below this, it is difficult to uniformly heat the entire side weir body. If the graphite content is less than 20% by weight, it is difficult to obtain a thermal conductivity of 15 W / m · K or more.

When the side weir body 11 is made of a graphite refractory, a material having high corrosion resistance such as high alumina or alumina-graphite is applied to a portion in contact with the molten steel so that the graphite body does not melt. It is preferable to do so.

The thermal conductivity of high alumina refractories is generally 2
While it is about W / m · K, the thermal conductivity of the graphite refractory is 50 W / m · K or more. Therefore, by using alumina-graphite or graphite refractory having high thermal conductivity, the side dam main body 11 can be heated uniformly.

Since the side weir body 11 is made of a material having a high thermal conductivity, the heater can be sufficiently uniformly heated only by heating from the back of the side weir body 11 without embedding a heater inside the side weir body 11. It is possible to do.

In the side pouring type weir, it is necessary to seal the peripheral surface of the lower roll 4 in order to form a pool. For this reason, as shown in FIG. 1, the ceramic sliding body 13 of the side weir body 11, which is a seal (sliding) member,
The shape conforms to the curvature of the lower roll surface.

This processing can be performed on the ceramic sliding body 13 alone. However, when fixing to the side weir case 12, it is necessary to fix the positional relationship at the time of fixing to a correct position, and to prevent a disorder due to thermal expansion at the time of preheating.

Therefore, in the present invention, the side weir main body 11
A material having a higher strength (harder) than other heat-insulating layers is applied to the portion 15a for fixing.

For simple positioning, a metal case (for example, an iron plate) itself may be used as a reference plane for setting the side dam body 11, but in this case, the temperature of the side dam body 11 decreases due to heat conduction from this portion. It cannot achieve its intended purpose.

Therefore, as the heat insulating material, it is preferable to use a heat insulating material having a positionable strength (hardness). As a result of various studies, the present inventors have found that the compressive strength of this portion is required to be 20 MPa or more.

The thickness d of the hard heat insulating layer 15a is
What is necessary is just to determine suitably from the balance of the heat conductivity of this part and the calorific value of a heater. Similarly, other heat insulating layers 15b
Can be determined based on the size of the heater box 12 and the thickness d of the hard heat-insulating layer 15a.

The heat insulating material 15a against which the side weir main body 11 is pressed preferably has a compressive strength of 20 MPa or more. Below this, there is a risk that the heat insulating portion will be missing during repeated attachment and detachment of the side dam, and it will not be possible to fix it in the correct position.

The heat insulating material 15 on the back of the side weir main body 11
It is preferable that a has a thermal conductivity of 0.5 W / m · K or less. When the thermal conductivity exceeds 0.5 W / m · K, the outflow of heat from the side weir body becomes too large, and the side weir body 11 cannot be sufficiently heated.

When there is no castable that can satisfy both the conditions of strength and thermal conductivity, it is possible to change the material of the amorphous refractory for each construction site.

Next, measures against thermal expansion of the side weir main body 11 during preheating will be described.

The side dam body 11 thermally expands due to preheating.
In the horizontal pouring type, so that there is no gap between the lower roll,
It is necessary to escape thermal expansion. As is well known, when a refractory is firmly fixed, cracks always occur, so this measure is necessary.

However, if the fixing is simply loose, a gap is formed between the lower roll and the ceramic sliding body 13.

Therefore, the hard heat insulating layer 15a of A, B and C shown in FIG. 2 is applied to the side weir case 12, and the surface is tightened with bolts 18 via coned disc springs 17 and springs. Since all thermal expansion escapes in the direction of the disc spring 17,
Almost no error occurs in the dimensional relationship with the lower roll. Even if a dimensional relation error occurs, the operation is not hindered.

The strength of the disc spring 17 to be fixed may be appropriately determined so as to be larger than the pressing force of the side weir body 11 against the lower roll 4 and equal to or less than the stress at the time of thermal expansion.

Since this portion also becomes high temperature due to the preheating of the side weir main body 11, the disc spring 17 is cooled by, for example, air or used in a casing of a water cooling jacket (FIG. 4).
reference). Further, the fixing screw 18 and the disc spring 17 may be mounted outside the side weir case.

Example 1 SUS304 was cast for 30 minutes by a horizontal casting type continuous casting apparatus using a side weir shown in FIG.

The approximate dimensions of the apparatus are as follows:
The body length was 1000 mm.

The side weir has a water-cooled steel plate welded structure inside the case, and the hard heat insulating layer has a thickness d based on the result of heat calculation.
Was 30 mm and the compression strength was 65 MPa. The other heat-insulating layers have a thermal conductivity of 0.2 W / m ·
The one of K was adopted.

A unitized heater having a power of 10 kW was used, a concave portion was formed on the heat insulating layer other than the hard heat insulating layer so that the gap was 3 mm, and a gap between the heater and the heater was filled with felt-like alumina fiber and fixed. .

[0062] side weir _{body, A1 2 0 3: 48%} ,
Alumina-graphite having a composition of C: 30% and SiO ₂ : 20% and having a thermal conductivity of 22 W / m · K was used. The ceramic sliding material was embedded in the groove of the side weir body and fixed with an inorganic adhesive (trade name: Sumiceram).

For comparison, Al ₂ was added to the side weir body.
0 ₃ 96%, a similar experiment was performed using the conventional side weir using high alumina castable thermal conductivity 1.3W / m · K.

As shown in FIG. 1, the side weir body was fixed so that the pressing direction of the disc spring was directed to the lower roll surface and the bottom nozzle side.

Casting was performed using the side weirs described above, and the following results were obtained.

1. In the case of the conventional side weir in which the side weir, heater, and heat insulating material are integrated, three
In the present invention, it took 10 minutes and about 1 minute, while it took 0 minutes or more.
/ 3 times. In addition, there was no breakage of the heater.

2. In the side weir of the present invention using a material with high thermal conductivity for the side weir body, the preheating temperature at the tip of the bottom nozzle of the side weir body can be set to 1000 ° C. or more,
There was no formation of a sticky shell during casting. On the contrary,
In the conventional example using a high alumina castable as the side weir body, the limit of the preheating temperature was 600 ° C., and a sticking shell was formed during casting, casting became unstable, and slab defects also occurred.

3. In the side weir of the present invention, the main body of the side weir did not crack due to thermal stress during preheating and casting. Further, the dimensional change of the R portion of the ceramic sliding material for sealing the circumferential surface of the lower roll in the radial direction was so small as to be negligible and did not hinder casting.

[0069]

According to the present invention, the time required for replacing the side weir body is greatly reduced by dividing the side weir body and the heater unit for heating the same and removably assembling them. Is possible. Further, damage to the heater unit (heater main body) and the like can be reduced, and the cost can be significantly reduced.

Further, by using a material having a high thermal conductivity, the problem of insufficient heating of the side weir, which is a problem peculiar to the horizontal pouring method, can be solved, the formation of a fixed shell can be prevented, and stable casting can be performed.

Further, by providing a hard heat insulating layer on the fixing portion of the side weir body and applying a fixing force to this surface, the dimensional change can be minimized, so No casting is possible.

[Brief description of the drawings]

FIG. 1 shows an embodiment of a side weir of a twin-roll horizontal casting continuous casting apparatus according to the present invention.

FIG. 2 is a heater box of a side weir of a twin-roll horizontal casting continuous casting apparatus of the present invention.

FIG. 3 is a sectional view taken along line AA of FIG. 1;

FIG. 4 is a view showing a water-cooled jacket type side dam holder in the twin-roll horizontal casting continuous casting apparatus of FIG. 1;

FIG. 5 is a diagram showing an external type side dam holder in the twin-roll horizontal casting continuous casting apparatus of FIG. 1;

FIG. 6 is a perspective view showing an outer shape of a horizontal casting type continuous casting nozzle.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Bottom nozzle 2 Side weir (nozzle) 3 Upper roll 4 Lower roll 5 Hot water surface 11 Side weir (nozzle) main body 12 Side weir case 13 Ceramic sliding material 14 Heater 15 Heat insulating material 15a Hard heat insulating layer 15b Low heat conductive heat insulating layer 16 Lower roll 17 Disc spring (spring) 18 Fixing screw 19 Heater unit 21 Molten steel contact start side 22 Bottom nozzle tip 23 Kiss point side

Claims (5)

[Claims] A side weir body (11) and a side weir body for a roll type horizontal pouring continuous casting apparatus for forming a pool of molten metal guided by the roll and installed on a roll. (11) is formed separately from a heater unit (19) for heating from the rear side, and the two are detachably assembled.
1) The ceramic sliding body (13) is used for the sliding part with the roll.
A side weir for a roll-type horizontal pouring continuous casting apparatus, comprising: 2. The side dam according to claim 1, wherein the side dam main body is formed of an alumina-graphite refractory. 3. The side dam according to claim 1, wherein the side dam body (11) is formed of a graphite refractory. 4. At least two heater units (19)
A kind of heat insulating material is arranged, a heat insulating material (15a) having a compressive strength of 20 MPa or more is arranged at a portion where the side weir body contacts, and a thermal conductivity of 0.5 W / m · K or less is arranged at other portions. The side dam according to claim 1, wherein a heat insulating material (15b) is arranged. 5. The side weir body (11) is pressed and fixed via a spring member (17) to thermally expand the side weir body in a direction opposite to the roll peripheral surface. The side weir of the roll-type horizontal pouring continuous casting apparatus described in the above.