JPH01122640A - Heat insulating blown coating material for tundish - Google Patents

Abstract

PURPOSE:To improve fluidity of heat insulating blown coating material for a tundish and to prevent hanging phenomenon by blending the specific quantity of the specific magnesia kind foam grain to magnesia kind coating material containing fibrous material. CONSTITUTION:In the magnesia kind coating material having about 2wt.% fibrous material for coating on the surface of lining refractory in the tundish, the magnesia kind foam grain having <=2mm grain size and 1.4-1.6 bulk density is blended at 20-80%. By this method, the fluidity of the material is made to good without any bad influence to the light wt. and heat insulation. The heat insulating blown coating material for the tundish obtd. by this can be smoothly coated without developing hanging in a tank at the time of blow working.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a magnesia-based spray coating material that is coated on the surface of a refractory lining of a tundish, and more specifically, in a spray tank during spray construction.

[Prior Art] Generally, the surface of the refractory lining of a tundish is coated with a refractory material that has functions such as heat insulation and resistance to penetration of molten steel in order to prevent contamination of molten steel within the tundish. It has become. Particularly in recent years, the continuous casting ratio in the steel manufacturing process has increased significantly, and as a result, demands for improving the quality of steel have become increasingly strict, and demands for the coating material have also become stricter.

As a result, the proportion of the coating material in the cost of continuous casting refractories has become extremely high, and therefore various efforts have been made to reduce the cost.

For example, a technology has been put into practical use that makes the thickness of the coating layer uniform by spraying with compressed air, and also adds fibrous substances or the like to reduce the weight of the refractory, thereby reducing costs.

[Problems to be Solved by the Invention] In the above-mentioned conventional technology, in order to promote weight reduction to a bulk specific gravity of about 1.8 or less, a large amount of fibrous material must be added. The fibers become entangled with each other, which impairs the fluidity of the material, causing problems such as a hanging phenomenon in the tank during construction, and the material not flowing smoothly. FIG. 1 shows the relationship between the amount of fibrous material added and the angle of repose, which is a measure of fluidity.

As a result of various studies, the inventors of the present invention developed a heat-insulating multi-cell pellet.

In particular, the present invention was completed by focusing on the fact that it is possible to improve the flow of the material by using an appropriate amount of magnesia-based multicellular particles in view of the problem of non-metallic inclusions. In other words, the present invention provides a thermal insulation spray coating material for tundishes that improves the fluidity of the material without adversely affecting the lightweight heat insulation properties and prevents the phenomenon of hanging shelves in a tank during spray construction. It is.

[Means for Solving the Problems] The present invention provides a magnesia-based coating material having a fibrous material to be coated on the surface of a refractory lining of a refractory material. This is a heat insulating spray coating material for tundishes containing 20 to 80% by weight of multicellular particles.

The present invention will be explained in detail below.

In the present invention, natural magnesia is used as the aggregate.

One or more types of electrofused magnesia, seawater magnesia, dolomite clinker, etc. are sprayed with a maximum particle size of 2 for ease of spraying.
The following particles are used with appropriate particle size adjustment.

As the fibrous substance, organic substances and inorganic substances can be used alone or in combination, and in consideration of expansion and absorption properties and troubles during construction, the addition amount is at most 2% by weight, preferably 1% by weight is sufficient.

Magnesia-based foam granules improve the fluidity of the material without adversely affecting lightweight insulation, and prevent the shelf-hanging phenomenon in the tank during construction. Those having a diameter of 2 mm or less and a bulk specific gravity of 1.4 to 1.6 are used with appropriate particle size adjustment. As mentioned above, from the viewpoint of spraying workability, the maximum particle size is set to 2 mm or less. Bulk specific gravity 1.4-1
．． The value of 6 is determined by taking into account the lightness of the insulation and the spraying workability, and this range is good. The amount added is 20~
80% by weight is preferable; if it is less than 20% by weight, the desired lightweight insulation cannot be achieved, and if it is more than 80% by weight, breathability may become high.

[Example] Adding 2% by weight of fibrous material to the binder and other additives, varying the amount of magnesia foam particles from 20% to 80% by weight, and adding natural magnesia to the remainder. The angle of repose, which indicates fluidity, and the bulk specific gravity of the clinker-containing formulation were measured. The results are shown in FIG.

[Effects of the Invention] According to the present invention, as detailed in Section 9 above, there is no adverse effect on the insulation and lightweight properties, and there is no occurrence of shelf hanging in the spray tank during spray construction, and construction can be carried out smoothly. It exhibits this excellent effect.

[Brief explanation of the drawing]

Figure 1 is a graph showing the relationship between the amount of fibrous material added and the angle of repose, and Figure 2 is a graph showing the relationship between the amount of magnesia foam particles added and the angle of repose when the amount of fibrous material added is 2% in the present invention. It is a graph.

Claims (1)

[Claims] A magnesia coating material having a fibrous substance that coats the surface of a tundish lining refractory material is characterized by containing 20 to 80% by weight of magnesia foam particles with a particle size of 2 mm or less and a bulk specific gravity of 1.4 to 1.6. Insulating spray coating material for tundishes.