JPS62166054A - Continuous casting device for thin sheet - Google Patents

Abstract

PURPOSE:To eliminate the wear, failure and thermal deformation of stationary gates and to stably cast a thin sheet by using refractory materials meeting respective functions to form the parts of the stationary gates which slide in contact with the end faces of water cooling drums rotating oppositely from each other and the parts in contact with a molten metal. CONSTITUTION:The stationary gates 2, 2' slide in contact with both end faces of the water cooling drum 1, 1' rotating oppositely from each other. The parts 2a of the stationary gates 2, 2' which slide in contact with the end faces of the drums 1, 1' are made of the hard refractory material such as ZrO2 which has good wear resistance and heat insulation characteristic. The parts 2b in contact with the molten metal 4 are made of the material such as boron nitride which has good heat resistance and thermal impact resistance, has a small rate of thermal deformation and good removability of solidified matter. The wear and failure of the stationary gates 2, 2' are eliminated and the thermal deformation in the parts in contact with the molten metal 4 is eliminated. As a result, the fluctuation in the width of the ingot is obviated and the stable thin sheet 3 is continuously cast.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a continuous thin plate casting apparatus, and more particularly to a twin drum type continuous thin plate casting apparatus characterized by the material of the fixed weir.

[Conventional technology]

The fixed weir material of the twin-drum continuous casting machine, which continuously casts thin plates by pouring molten metal into the space created by two internal water-cooled drums and two fixed weirs pressed against the drum end faces, is (L+ heat resistant). Excellent (molten steel temperature 1600G)
(2) Excellent thermal shock resistance (ΔT=4ooc)
(3) Small amount of thermal deformation (low coefficient of thermal expansion) (4) Excellent releasability of solidified material (poor wettability with molten steel) (5) Excellent wear resistance, etc. functionality is required.

However, there is no fixed weir material that can satisfy all of these functions, but boron nitride (BN), which satisfies relatively many of the required functions, has been conventionally used as a refractory material for fixed weirs.

By the way, as mentioned above, continuous casting of thin plates by pouring molten metal into the space created by two internal water-cooled drums and two fixed weirs pressed against the end surfaces of the drums. In conventional twin-drum continuous casting equipment, boron nitride is used for the fixed weir material pressed onto the end surface of the internal water-cooled drum, but the contact parts wear out due to sliding of the drum. Problems have arisen, such as variations in the width of the cast slab and damage to the boron nitride, making casting impossible.

〔the purpose〕

SUMMARY OF THE INVENTION An object of the present invention is to provide a continuous thin plate casting apparatus t that solves the above-mentioned problems, that is, problems associated with wear and breakage of fixed weirs.

[Means for solving problems]

As a means to achieve the above object, the present invention does not consist of a single type of refractory material as the fixed weir material, but instead includes a portion that slides in contact with the end surface of the water-cooled drum and a portion that contacts the molten metal. The key point is that a fixed weir with a so-called composite structure is used, which is made of fireproof materials according to the function of each part. That is, the present invention consists of two water-cooled drums that are arranged horizontally in parallel with a gap that corresponds to the thickness of the metal strip to be manufactured, and that rotate in different directions. In a continuous casting device for pouring molten metal into a space formed by a fixed weir to obtain a thin plate, refractory materials are used according to the functions of the parts where the fixed weir contacts and slides on the end surface of the water-cooled drum, and the parts that come into contact with the molten metal. This continuous thin plate casting apparatus is characterized by using a fixed weir constructed of:

The part where the solid leg weir contacts and slides on the end surface of the water-cooled drum is prone to wear and damage. Therefore, in the present invention, the material of the identified weir in this part is a material that is hard, has excellent wear resistance, and has good heat insulation properties. For example, ZrO, BN +Si3N4. A
A fireproof material such as /203 is used.

On the other hand, in the part where the fixed weir contacts the molten metal, thermal deformation is likely to occur due to the high temperature of the molten metal. Therefore, in the present invention, the material of the fixed weir in this part should have good heat resistance and thermal shock resistance, and the amount of thermal deformation. Materials with a small particle size and good releasability of coagulum, such as boro/nitride, graphite, A
I! A fireproof material such as 203+ graphite is used.

〔Example〕

The present invention will be explained in detail based on FIGS. 1 to 3. FIG. 1 is a vertical cross-sectional view of a continuous thin plate casting apparatus according to an embodiment of the present invention, FIG. 2 is an enlarged detailed view of the fixed weir in FIG. 1, and FIG. -A sectional view. The apparatus shown in FIG.
, side fixed weirs 2 and 2' to completely prevent leakage of the molten #J4 between the water-cooled casting drums 1 and 1', a tundish 5 for storing molten metal such as molten steel, a pouring nozzle 6, etc. as structural members. There is.

To explain this device in detail, the water-cooled casting drums 1, 1'
is installed horizontally and is rotated (in the direction of the arrow) by a drive device itK (not shown).

The water-cooled casting drums 1, 1' are made of copper or copper alloy, for example.
Alternatively, the drum is made of Vi steel and has a considerably large diameter in order to obtain a large contact area with the molten metal 4. Furthermore, fixed weirs 2 and 2' made of refractory material for sealing the sides are pressed out at both ends of the water-cooled casting drums 1 and 1'. The molten metal 4 is poured into the space formed by the fixed weirs 2°7 through the pouring nozzle 6.
is poured. The poured molten metal 4 is placed in a water-cooled casting drum 1.
The solidified shell is cooled when it comes into contact with the surface of the slab 1', and the resulting solidified shell is integrated into the slab 3. This slab 3 is made of Vinci roll 7
It is pulled out.

The action of the fixed weir 2.2' of the device shown in FIG. 1 will be explained in detail in comparison with the fixed weir of the conventional device based on FIGS. 4 and 5. Note that FIG. 4 is an enlarged detailed view of a fixed weir in a conventional device and corresponds to FIG. 2, which is an embodiment of the present invention, and FIG. 5 is an enlarged detailed view of a fixed weir in a conventional device. It is a cross-sectional view, and corresponds to FIG. 3, which is an embodiment of the present invention.

The conventional fixed weirs 2, 2' are made of one type of fixed weir material (refractory material), as shown in FIGS. 4 and 5. That is, the parts that come into contact with the melt ah 4 and the parts that come into contact with the water-cooled casting drums 1 and 1' are made of the same material. If a hard refractory material (such as AI!0 or ZrO2) is used as the fixed weir material, it will have excellent wear resistance due to sliding with the water-cooled casting drums 1 and 1', but it will not be susceptible to thermal shock. This weakens the refractory material and causes it to crack and breakout. Also, in the case of soft refractory materials (for example, boron nitride, graphite, or Al 203 + graphite), they are strong against thermal shock but weak against abrasion, and one type of refractory material does not have the heat resistance, abrasion resistance, and resistance required for fixed weir materials. It is not possible to satisfy the impact resistance function. Therefore, the present invention has developed the through hole, fixed weir 2, 2/ shown in FIG. 2 and FIG.
The part 2b in contact with the
120. + graphite, and the sliding part 2& with the drum 1.1' is hard and has excellent wear resistance (5) material with good heat insulation properties, such as ZrO2, B N + Si, N4゜A
12o5, which satisfies all the functions required of a fixed weir KM.

〔Concrete example〕

To illustrate a specific example of the present invention, the dimensions and various conditions of the structural members in the case of casting steel are as follows.

(1) Water-cooled casting drum Made of steel with internal water cooling system, roll diameter 2.000nφ
A water-cooled casting roll with a roll width of 1,20011 mm is used.

The slab dimensions are 3 x 1200 x 1200 x 1,200 x 1200 x 1200 x 1200 x 1200 x 1200 x 1200 x 1200 x 1200 x 1200 x 1200 x 1200 x 1200 x 1200 x 1200 x 1,200 x 1200 x 1200 x 1,200 x 1,200 x 1,200 x 1,200 x 1,200 x 1,200 mm wide, and the roll rotation speed at this time was approximately 2 f3 m/min.

(2) Al2O3+graphite was used for the part in contact with the fixed weir molten metal, while Si3N4+BN was used for the sliding part with the drum.

(3) Molten metal In the case of ordinary steel, the temperature of the molten metal in the tundish is 1520~1
It is 560°C.

Casting was carried out under the above conditions, and good slabs could be stably obtained without any operational troubles such as breakouts. In other words, the part of the solid weir material that comes into contact with the molten metal is AI! 2
0. As a result of using 5i3u4+BN for the sliding part with the drum, there is no variation in the width of the manufactured slab due to wear at the contact part due to the sliding of the drum, and a fixed weir is used. This eliminates material damage and enables stable casting over a wide area.

〔effect〕

As described in detail above, in the present invention, the part of the fixed weir that comes into contact with and slides on the end surface of the water-cooled drum and the part that comes into contact with the molten metal are made of fireproof material according to the function of each part. , there is no wear or damage to the fixed weir at the sliding contact part with the drum, and there is no thermal deformation at the contact part with the molten metal.As a result, there is no variation in the width of the slab, resulting in stable casting. The effect is that it becomes possible.

[Brief explanation of drawings]

FIG. 1 is a vertical sectional view of a continuous thin plate casting apparatus according to an embodiment of the present invention, and FIG. 2 is an enlarged detailed view of the fixed weir in FIG.
FIG. 3 is a sectional view taken along the line A--A in FIG. 2. Figure 4 is an enlarged detailed view of the fixed weir in a conventional thin plate continuous casting machine;
The figure is a sectional view of the fixed weir. 1) Meifuku agent Ryo Hagiwara - Sub-agent Atsuo Anzai Figure 4 Figure 5 z, Z

Claims (1)

[Claims] It is formed by two water-cooled drums that rotate in different directions, placed horizontally in parallel with a gap corresponding to the thickness of the metal strip to be manufactured, and two fixed weirs pressed against the end surfaces of these water-cooled drums. In a continuous casting machine for pouring molten metal into a space to obtain thin plates, the fixed weir is made of refractory material according to the function of the part where the fixed weir contacts and slides on the end surface of the water-cooled drum, and the part that comes into contact with the molten metal. A thin plate continuous casting device characterized by using a weir.