JPH05261489A - Side weir for strip continuous casting machine - Google Patents

Abstract

PURPOSE:To effectively restrain the generation of solidified shell produced on a side weir surface and to prevent troubles of breakout, drawing stop, etc., and also to perfectly prevent fall-down defect of the solidified shell on the side weir for a strip continuous casting machine. CONSTITUTION:The side weir 1 laminatedly joins a heat insulating material 3 and a refractory material 4 to a metal plate 2 in order and also grooves 5 in length and breadth are arranged on the back surface of the refractory 4 to form air gap, and the area ratio of this air gap is made to be >=50%.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin cast continuous casting machine equipped with a pair of cooling moving walls (rolls, belts, etc.) that move in opposite directions, and is provided on both end faces of the cooling moving walls to provide a molten metal pool. It relates to a side weir for forming.

[0002]

2. Description of the Related Art A twin roll type continuous casting machine will be described below as an example in order to facilitate understanding of the present invention. As shown in FIG.
The twin roll type continuous casting machine forms a molten metal pool P by a pair of internal cooling rolls 6 rotating in opposite directions and side dams 7 provided on both end faces of the cooling roll 6 and pouring the molten metal pool P into the molten metal pool P. The molten metal thus obtained is cooled by a cooling roll 6 to form a solidified shell, and a thin cast piece 8 is manufactured by drawing between the twin rolls.

However, in the above casting, the solidified shells are formed not only on the cooling roll 6 surface but also on the side dam 7 surface. Therefore, when the solidified shell on the side dam 7 surface increases to some extent, the solidified shells are connected to the solidified shell on the cooling roll 6 surface. As shown in FIG. 5, the solidified shell on the surface of the side dam 7 is taken into the slab 8 and becomes the collapse defect 9 of the solidified shell. Further, if the solidification on the surface of the side dam 7 becomes large, a breakout will occur or it will not be possible to draw out.

Therefore, in order to delay the solidification on the side dam surface and prevent the above troubles, the side dam 7 is made of a refractory material and a heat insulating layer is provided on the back surface thereof (JP-A-64).
-2764) or heating the side dam 7 (Japanese Utility Model Laid-Open No. 63-196340).

[0005]

Although the above-mentioned improvement measures are recognized to have some effect, it is still insufficient to provide a heat insulating layer on the back surface of the refractory as in the former case, and heating as in the latter case. It is difficult to uniformly heat the entire surface of the side dam 7 to a high temperature by the measures, and it is the actual situation that the above-mentioned problem has not been completely solved.

The present invention is intended to solve the above-mentioned drawbacks of the prior art, and the purpose thereof is to effectively suppress the generation of solidified shells generated on the side dam surface and prevent troubles such as breakout and drawing stop. Another object of the present invention is to provide a side weir for a thin cast continuous casting machine, which can completely prevent the falling defect of the solidified shell.

[0007]

In order to achieve the above object, a side weir for a thin cast continuous casting machine according to the present invention comprises:
A side dam for a thin cast continuous casting machine, which is provided on both end faces of a pair of cooling moving walls that move in mutually opposite directions to form a molten metal pool, and is provided with a heat insulating material on the back surface of the refractory material in contact with the molten metal. An air gap having an area ratio of 50% or more is formed between the joint surfaces of.

The air gap may be formed by a large number of grooves.

[0009]

In the present invention, since the heat insulating material is provided on the back surface of the refractory material forming the side dam and the air gap is provided between the joining surfaces of the two, the heat insulating effect can be enhanced as compared with the heat insulating material alone. Therefore, it is possible to effectively suppress the generation of solidified shells generated on the side dam surface without heating the side dam. In order to fully enjoy such effects, the size of the air gap provided between the joint surfaces should be 50% or more in terms of area ratio, and if it is less than 50%, solidified shells will be generated and slabs will be observed. The collapse defect of the solidified shell was recognized. Further, although the upper limit is not particularly limited,
It is preferably up to 80% in order to obtain sufficient strength to withstand the pressing force when the side dam is pressed against the side wall of the cooling moving wall to form the molten metal pool and to be able to bond the heat insulating material to the back surface of the refractory.

Further, when an air gap having the above area ratio is provided between the joint surfaces, in order to obtain a more uniform heat insulating effect between the joint surfaces and to obtain a pressure resistance between the joint surfaces,
It is preferable to form a large number of vertical, horizontal and diagonal grooves.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic view of a side weir for a twin roll type continuous casting machine according to the present invention, in which a is a perspective view of the whole and b is a rear perspective view of the refractory.

The side weir 1 has a structure in which a heat insulating material 3 and a refractory material 4 are laminated and joined to a metal plate 2 in this order. In this example, the side surface of the refractory material 4 is arranged vertically and horizontally as shown in FIG. 1b. The groove 5 was provided to form an air gap.

Next, the side weir 1 having the above-mentioned structure is pressed from the side as shown in FIG. 4 to a twin roll type continuous casting machine equipped with a copper alloy roll 6 having a diameter of 400 mm and a length of 300 mm and internally cooled. To form a molten metal pool P, and using this casting machine, the thickness of the molten metal of SUS304 is 2 mm × width 3
A 00 mm thin slab was produced.

In the above casting, while the grooves 5 formed on the back surface of the refractory 4 are provided at intervals of 10 mm, the groove shape is cast at a depth of 1 mm and the width of the air gap is changed to change the area ratio of the air gap. The relationship between the area ratio and the falling defect of the solidified shell appearing in the obtained slab was investigated. The survey results are shown in FIG. At this time, two types of SiO ₂ and MgO were used as the heat insulating material 3.

Further, in parallel with the above investigation, a thermocouple was provided between the heat insulating material 3 and the refractory 4 to measure the temperature in order to confirm the heat insulating effect by the air gap. Fig. 3 shows a comparison of the temperature measurement results when the area ratio of the air gap is 60% and when it is zero (conventional one).

As is clear from FIG. 2, as the area ratio of the air gap formed between the joint surface of the heat insulating material 3 and the refractory 4 increases, the falling defects of the solidified shell decrease and the area ratio is 50%. Then, almost no defects were found. This tendency was the same regardless of the material of the heat insulating material 3 (SiO ₂ type, MgO type), and the defect reduction effect was also the same.

Further, as is clear from FIG. 3, in the example of the present invention (air gap area ratio 60%), a comparative example (zero air gap area ratio) in which the heat insulating material 3 and the refractory 4 were simply joined was used. By comparison, it can be seen that the temperature is high and the temperature is constant at an early stage, and the adiabatic effect is high.

[0018]

As described above, according to the side weir for a thin cast continuous casting machine according to the present invention, it is possible to effectively suppress the generation of the solidified shell generated on the side weir surface during casting.
Further, this makes it possible to prevent troubles such as breakout and drawing stoppage, and to completely prevent slab defects due to the collapse of the solidified shell, thereby improving the productivity of the thin slab continuous casting machine.

[Brief description of drawings]

FIG. 1 is a schematic view of a side weir for a twin roll type continuous casting machine according to the present invention, in which a is a perspective view of the whole and b is a perspective view of a back surface of a refractory material.

FIG. 2 is a graph showing the relationship between the area ratio of the air gap and the falling defect of the solidified shell appearing in the obtained slab.

FIG. 3 is a graph showing a change with time in temperature between a joint surface of a heat insulating material and a refractory material.

FIG. 4 is an enlarged explanatory view of a main part of a twin roll type continuous casting machine.

FIG. 5 is an explanatory view of a falling defect aspect of a solidified shell generated on a side portion of a cast piece.

[Explanation of symbols]

1: Side weir 2: Metal plate 3: Heat insulating material 4: Refractory material 5: Groove 6: Internal water-cooled copper alloy roll

Claims (2)

[Claims] 1. A side weir for a thin cast continuous casting machine, which is provided on both end faces of a pair of cooling moving walls that move in opposite directions to each other to form a molten metal pool, and is insulated on the back surface of the refractory material in contact with the molten metal. A side dam for a thin cast continuous casting machine, which is characterized in that an air gap having an area ratio of 50% or more is formed between the joining surfaces of the two materials. 2. The side dam for a thin cast continuous casting machine according to claim 1, wherein the air gap is formed by a large number of grooves.