JPH07214248A - Contact limiting plate for twin roll type continuous casting machine - Google Patents

Abstract

PURPOSE:To provide a contact limiting plate which prevents adhesion of slag and base metal with a twin roll type continuous casting machine for producing a thin slab. CONSTITUTION:An antiwetting material 8 is applied at the front end to be immersed into a pouring basin part 3 of the contact limiting plate 4 of the twin roll type continuous casting machine which fixes a solidification start point 6 of the molten metal charged into the molten metal pouring basin part 3 formed between two pieces of rolls 1a and 1b. As a result, the adhesion of the slag and base metal is prevented and the position of the solidification start point is maintained constant. A solidified shell of always normal thickness is formed. The surface characteristic and accuracy of the slab are thus maintained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a contact limiting plate which prevents adhesion of slag and metal in a twin roll type continuous casting machine for producing thin plate slabs.

[0002]

2. Description of the Related Art A twin roll type continuous casting method in which molten steel is poured between two rolls which are rotated inward and a thin metal plate is cast is known as a Bessemer method.

In this method, two rolls are arranged at an appropriate interval, and when the molten metal is injected from above and rotated inwardly, the injected molten metal comes into contact with the rolls to remove heat, As a result, a solidified shell is formed on the roll surface,
The two solidified shells are joined together as the roll rotates, and are further pressed to form a slab having a predetermined thickness, which is then delivered below the roll to produce a thin slab.

In this case, the solidified shell starts solidifying at the point where the molten metal comes into contact with the roll, continues to grow, and becomes a solidified shell having a predetermined thickness at the roll kiss point. Since it becomes a slab, in order to maintain the accuracy of the thickness of the slab to be manufactured, it is necessary to always control the distance from the solidification start point to the roll kiss point to be constant.

As a technique for controlling the distance from the solidification start point to the roll kiss point, for example, Japanese Patent Publication No. 62-5881.
There is a technique of a twin roll type casting and rolling mill disclosed in Japanese Patent Publication No. 1 and its control method.

According to this technique, a contact limiting plate for adjusting a contact area between the roll and the molten steel is provided in a molten steel pool formed by two rolls, and a contact limiting plate sliding on the surface of the roll is provided. This is a control method of a twin roll type casting and rolling mill in which the position is set to a desired value and the contact area between the molten steel and the roll in the pool is controlled to control the thickness of the solidified shell formed.

In this case, the formed thickness of the solidified shell is substantially proportional to the arc length from the solidification start point where the tip of the contact limiting plate contacts the roll to the roll kiss point. The shell grows faster,
By appropriately adjusting the position of the contact limiting plate, the thickness of the solidified shell formed can be controlled, and the manufactured slab can be accurately maintained.

[0008]

[Problems to be Solved by the Invention]
When the operation is continued for a long time, slag adheres to the tip of the contact limiting plate, that is, the surface of the solidification starting point, and the metal also adheres and grows accordingly. Therefore, there was a problem that the position of the solidification starting point fluctuates during the operation, the thickness of the solidified shell formed changes, and the accuracy of the manufactured slab deteriorates, and the surface quality becomes poor.

Further, it is very difficult to remove the adhered metal or slag during operation from the working environment,
It is necessary to stop the operation and remove each time, and there is also a problem that the production efficiency is deteriorated due to the reduction of the operating rate of the casting machine and the removal work.

The present invention has been made in view of the above problems,
Provided is a contact limiting plate which prevents adhesion of slag and metal in a twin roll type continuous casting machine.

[0011]

The present invention relates to a contact limiting plate of a twin roll type continuous casting machine for charging a molten metal pool portion formed between two rolls and fixing a solidification start point of the molten metal. The contact limiting plate of a twin roll type continuous casting machine is characterized in that an anti-wetting substance is applied to a tip end portion of the contact limiting plate which is immersed in a molten metal pool.

[0012]

[Function] The contact limiting plate to be charged in the basin is mainly composed of silica and alumina floating in the basin when materials such as silica and alumina are used as they are when casting molten steel containing silicon or aluminum. The wettability with the slag as a component is high, the slag adheres, and the ingot easily grows accordingly. Especially, the back surface and upper half of the contact restriction plate are cooled by contact with outside air or a roll for casting.Since the temperature of the contact restriction plate is lower than that of the molten metal, slag and metal are fixed and grow at the tip. To do.

According to the present invention, an anti-wetting substance is applied to the tip of the contact limiting plate which is immersed in the molten metal pool to prevent the slag and the metal from sticking and growing at the solidification starting point, and at the solidification starting position. It is intended to maintain the accuracy of the slab produced by always maintaining the normal temperature and obtain a slab with a good surface quality.

As the anti-wetting substance, a refractory having an anion different from the slag component, such as boron or silicon nitride,
Amorphous refractories such as carbides of silicon and zirconium, borides of zirconium, etc. and solvents using sodium silicate (water glass) as a solvent also have low wettability and are suitable for the present invention.

[0015]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 (a) is a side view showing an example of a twin roll type thin plate continuous casting machine, and FIG. 1 (b) is a drawing showing an example of a contact limiting plate coated with an anti-wetting substance. Reference numerals 1a and 1b denote a pair of casting rolls. Side weirs 2 are attached to opposite side surfaces of the upper part of the rolls to form a pool 3 of molten metal between the rolls.

A contact limiting plate 4 is inserted into the roll surface of the pool 3 from above, and the solidification shell 5 has an arc length from the solidification start point 6 at which the contact limiting plate 4 contacts the roll to the roll kiss point 7 approximately. Grow in proportion.

The contact limiting plate 4 has sodium silicate as a solvent at the tip end thereof which is immersed in the basin 3 and an amorphous refractory material such as boron, nitride of silicon, carbide of silicon and zirconium, boride of zirconium, etc. as a solvent. Mix (water glass) with the solvent used and apply.

By thus applying the anti-wetting substance 8 to the tip of the contact limiting plate 4 which is immersed in the pool 3 of the contact limiting plate 4,
Since the slag and the metal are prevented from sticking and growing at the solidification start point, the position of the solidification start point 6 is always kept constant, and the slab produced by producing the solidification shell 5 with a normal thickness is manufactured accurately. A slab that is maintained and has a good surface quality can be obtained.

[0020]

As described above, according to the present invention, since the anti-wetting substance is applied to the tip of the contact limiting plate, adhesion of slag and metal is prevented, and a solidified shell having a normal thickness for a long time is provided. Maintains the accuracy of the slab that is produced and manufactured,
A slab with good surface quality can be obtained.

Further, the work of removing slag and the like during the operation becomes unnecessary, the operating rate of the casting machine is improved, and the production efficiency can be increased.

[Brief description of drawings]

1 shows an embodiment of the present invention, FIG. 1 (a) is a side view of a twin roll type thin plate continuous casting machine, and FIG. 1 (b) is an example of a contact limiting plate coated with an anti-wetting substance. FIG.

[Explanation of symbols]

 1a, 1b Casting roll 2 Side weir 3 Hot water pool 4 Contact limit plate 5 Solidification shell 6 Solidification start point 7 Roll kiss point 8 Application surface of anti-wetting substance

Continuation of front page (72) Inventor Shiomi Kiyomi 20-1 Shintomi, Futtsu City, Chiba Nippon Steel Co., Ltd. Technology Development Division

Claims (1)

[Claims] 1. A contact limiting plate of a twin roll type continuous casting machine for charging a molten metal pool formed between two rolls and fixing a solidification start point of the molten metal, wherein the molten metal pool part of the contact limiting plate. A contact limiting plate for a twin roll type continuous casting machine, characterized in that an anti-wetting substance is applied to a tip portion of the twin roll type continuous casting machine.