JPH0796148B2 - Short side plate of thin cast continuous casting machine - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a short side plate that forms a casting space together with a pair of circulating bodies in a thin cast continuous casting machine that directly manufactures a thin cast from molten metal. .

(Prior Art) A continuous casting machine (that is, a belt caster) that continuously manufactures a thin cast piece such as a sheet bar directly from a molten metal (hereinafter, described as an example of "molten steel") has various types recently. Is proposed. FIG. 2 shows a typical example thereof. The exemplified synchronous belt caster is of a narrowing type, and while maintaining a gap for holding a casting material such as molten steel or a solidified shell over a predetermined distance, through a plurality of guide rolls 3a, 3b, 3c, respectively. Metal belts 1 and 2 that support a pair of long side faces that are arranged to face each other and rotate
And the narrow side walls 4 and 5 in the shape of the upper and lower sides of the upper and lower sides for supporting the short side surfaces that are in close contact with each other between the two metal belts and are close to each side edge. It is designed as a space.

When molten steel is supplied to the casting space from the immersion nozzle 6, the molten steel contacted with the metal belts 1 and 2 cooled by the cooling pads 7a and 7b is drawn downward while forming a solidified shell.

Here, in order to delay the solidification on the short side surface, it is advantageous to form the inner surface of the short side plate in contact with the molten steel with a refractory, and in JP-A-58-218360, a frame is formed on the side edge in contact with the metal belt. It discloses a short side plate in which a refractory is supported by a frame part on a metal plate (cooling copper plate) having parts.

Providing the frame portion is effective not only for supporting the refractory but also for promoting solidification in the corner portion of the casting space and preventing molten steel from entering between the short side plate and the metal belt.

Further, JP-A-58-218356 discloses an effective means for preventing solidification on the refractory surface by embedding a heating element in the refractory material and positively heating the refractory material.

(Problems to be solved by the invention) If the solidification of molten steel on the refractory surface is avoided by the means as described above, the solidification shell on the short side is avoided in order to avoid increasing the drawing resistance of the slab. Will form and grow on the cooled copper plate below the refractory.

The problem here is that there is a gap (hereinafter referred to as joint) at the horizontal boundary between the refractory and the cooling copper plate, and molten steel may be inserted into this joint, or the refractory may be damaged from the joint. Is to imitate. Therefore, making the joint cost as narrow as possible is one of the steps that requires special attention when assembling the short side plates, but it is impossible to completely close the joints, and there is a problem in operation starting from the joints. Was difficult to solve.

Therefore, an object of the present invention is to propose a short side plate that can advantageously solve the problem caused by the above-mentioned joint.

(Means for Solving the Problem) The present invention is directed to a pair of opposed circulating bodies that circulate while maintaining a gap for holding a molten metal over a certain distance, and both side edges between the circulating bodies. In the short side plate of the thin cast continuous casting machine, which forms a casting space with a pair of upper and lower concavities which are located in the upper part and is narrowed toward the middle part, The refractory supported between the frame parts is combined with a metal plate having frame parts formed on both side edges in contact with each other, and the refractory product extends toward the casting space at the lower end and extends below the end point. Provided,
Laminated structure of a refractory surface layer with high thermal conductivity and excellent corrosion resistance and wear resistance, and a refractory surface layer with excellent heat insulation provided on the back surface of this refractory surface layer over the area above the end point of narrowing The short side plate of the thin cast continuous casting machine, characterized in that

(Function) There is always a joint between the refractory and the copper plate on the short side plate.

This joint is a gap necessary for attaching the refractory to the copper plate, and various efforts have been made to minimize this gap, but for example, a gap having a width of 0.3 mm to 1.0 mm or more is not possible. Inevitable. When setting the refractory, the joint is filled with mortar. Although this mortar uses high heat resistance, it is unsuitable for application to a continuous casting machine for thin cast pieces that require high corrosion resistance and wear resistance due to weak bonding force between particles. This is because the mortar filled in the joints peels off during casting, creating a gap between the refractory and the metal plate (copper plate), and especially when this gap occurs in the horizontal direction, the insertion of the metal into the breakout can easily occur.

Short side plate according to the present invention, the lower end of the refractory surface layer arranged on the side that contacts molten steel, that is, since the joint is arranged below the narrowing end point of the short side plate, the joint hardly contacts molten steel, That is, since the solidified shell has already been generated in the joint portion, the molten steel is prevented from being inserted into the joint.

Furthermore, in order to improve the cooling capacity by providing a heat-resistant refractory back layer in the area above the end point of refining of the entire surface of the refractory and increasing the thermal conductivity in the area below the end point of the refining,
The formation of the solidified shell after the end point of the narrowing is surely progressed, so that the molten steel is not inserted into the joint.

(Embodiment) FIG. 1 shows a short side plate according to the present invention.

In the figure, 8 is a side plate body in which frame portions 9 are formed on both side edges of a metal plate such as a copper plate, 10 is a refractory material supported by the frame portion 9, and 11 is a refrigerant passage through which water or the like circulates. The refractory 10 has a refractory surface layer 10a having a high thermal conductivity and excellent corrosion resistance, spalling resistance, and abrasion resistance, which is provided on a surface in contact with molten steel and extends below a narrowing end point P. Material surface 1
It is combined with a refractory backing layer 10b excellent in heat insulation provided on the back surface of the area above the narrowing end point P in 0a.

Here, the refractory surface layer 10a is a material such as sialon, silicon nitride, zirconia or a composite material having excellent corrosion resistance and hot abrasion resistance, while the refractory back layer 10b is MgO board, SiO ₂ board. Etc. are suitable for each.

Next, the continuous casting using the short side plate according to the present invention will be specifically described.

The short side plate of the structure according to Fig. 1 is used for the belt caster of Fig. 2, and the casting speed of low carbon aluminum killed steel is 10m / min.
Was cast into a slab with a thickness of 30 mm and a width of 1200 mm. In addition, a Cu material containing Ag is used for the frame portion of the short side plate, and a refractory surface layer with high thermal conductivity is used.
Sialon-BN (20%) composite material is used for 10a (5 mm thickness), MgO board is used for the refractory backing layer 10b (20 mm thickness) with higher heat insulation properties, and refractory surface layer 10a is the end point P
It was extended by 80 mm downward from. The length from the narrowing end point P to the upper end at the width center of the short side plate is 650 m.
Similarly, the distance from the end point P of narrowing down to the lower end is 250 mm. The characteristics of each refractory are shown in the table below.

When continuous casting was performed according to the above-mentioned conditions, it was possible to stably perform casting up to 1000 m per heat without inserting the metal into the joint.

(Effects of the Invention) According to the present invention, molten metal is not inserted into the joint between the refractory material and the copper plate, and therefore the continuous casting length can be increased and stable casting can be realized.

[Brief description of drawings]

 FIG. 1 is an explanatory view showing a short side plate according to the present invention, and FIG. 2 is an explanatory view of a belt caster. 1,2 ... Metal belt 3a, 3b, 3c ... Guide roll 4,5 ... Short side plate, 6 ... Immersion nozzle 7a, 7b ... Cooling pad, 8 ... Side plate body 9 ... Frame part, 10 ... Refractory 10a ... Refractory Surface layer, 10b ... Refractory back layer 11 ... Refrigerant passage

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Masayuki Onishi, No. 1 Kawasaki-cho, Chiba-shi, Chiba Inside the Kawasaki Steel Co., Ltd. (72) Takao Koshikawa No. 1, Kawasaki-cho, Chiba, Chiba Steel Co. In-house (72) Inventor Tomoaki Kimura 3-1-1 Sachimachi, Hitachi City, Ibaraki Hitachi Ltd. Hitachi Works, Hitachi Plant (56) Reference JP 62-212041 (JP, A)

Claims (1)

[Claims] 1. A pair of opposed circulating bodies that circulate while maintaining a gap for holding a molten metal over a certain distance, and a pair of circulating bodies located on both side edges between the circulating bodies. In the short side plate of the thin slab continuous casting machine that forms the casting space with the short side plate that is narrowed toward the middle part in the shape of the upper and lower sides, the frame part is formed on both side edges in contact with the circulating body. The refractory supported between the frame parts is combined with the metal plate, and the refractory has a high thermal conductivity, which is provided by extending the lower end toward the casting space and squeezing the lower end. It has a laminated structure of a refractory surface layer with excellent corrosion resistance and abrasion resistance, and a refractory back layer with excellent heat insulation provided over the area above the end point of narrowing on the back surface of this refractory surface layer. The short side plate of the thin cast continuous casting machine.