JPS63299852A - Coating material for metallurgical molten metal vessel - Google Patents

Abstract

PURPOSE:To improve erosion resistance and to contrive lightening by constituting coating material for metallurgical molten metal vessel of the specific amount of porous magnesia clinker and the balance general coating material and binder. CONSTITUTION:This coating material is contained of 10-50wt.% the porous magnesia clinker having high refractoriness and erosion resistance as aggregate and the balance the general coating material of the magnesia clinker, etc. By this method, as the lightening is obtd., the heat insulating property is improved and as burning with lining refractory is reduced, maintenance of a tundish is facilitated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a coating material for a molten metal container for metallurgy, particularly a tundish.

[Prior art and its problems]

For metallurgical vessels, especially tundishes, a coating material mainly composed of magnesia aggregate or the like can be sprayed or troweled to protect the lining material of the tundish or to facilitate maintenance of the tundish. It is being said.

Providing this sprayed material with heat insulating properties is effective in achieving the above-mentioned purpose, and can also prevent burning with the lining material. Furthermore, since the weight can be reduced, the amount used can be reduced, and steel manufacturing costs can be lowered.

Weight reduction methods include adding natural lightweight aggregates (perlite, vermiculite), foamed silica, organic fibers such as inorganic fibers (asbestos, rock wool, glass fiber, etc.), and foaming agents alone or in combination. .

However, the above-mentioned lightweight aggregate and inorganic fibers themselves have low melting points, and they not only reduce corrosion resistance because they react with magnesia aggregate to form a melt during use, but they also contain silica and alumina components. Molten liquid is undesirable because it contaminates the steel, and cannot be used in large quantities.

Organic fibers and foaming agents decompose and disappear when heated, so
Although by itself it does not have a negative effect on corrosion resistance, when added in a large amount, it weakens the strength of the construction body, resulting in a decrease in corrosion resistance.

The present invention has been proposed in view of the above-mentioned conventional circumstances, and is a coating for metallurgical molten metal containers that does not contaminate steel, has low corrosion resistance and reduced strength, and is highly lightweight. The purpose is to provide materials.

[Means for solving problems]

In order to achieve the above object, the present invention employs the following means. In other words, the porous talin strength of magnesia, which has high fire resistance and corrosion resistance, is used as an aggregate by 10 to 50% by weight.
It is made to contain. The remainder of the porous clinker of this coating material is composed of a general coating material such as magnesia krysica.

[Effect]

The above-mentioned porous talin powder is prepared by kneading fine magnesia powder with a foaming agent, granulating it, and firing it at around 1500°C, or
As disclosed in the above publication, a material prepared by contacting powder containing magnesium oxide or magnesium hydroxide with acetic acid or an acetic acid solution under heating can be used.

Porous tallincar is used in an amount of 10-50% by weight. If the amount used is less than 10% by weight, the weight reduction effect will be small;
If the amount is more than 0% by weight, the workability during painting or spraying will deteriorate, which is not preferable.

In the coating material of the present application, raw materials other than porous magnesia clinker include magnesia clinker 1, lime talinker, and dolomite clinker 1, which are conventionally known.
Examples include fireclay and fine silica powder, and it can be manufactured by adding a binder such as condensed sodium phosphate to these.

Further, conventionally used materials such as natural fibers can be used in combination without impairing corrosion resistance.

[Example-1] Examples of the formulation of the coating material based on the present invention are shown in Table 1 together with Comparative Example (11).

The porous magnesia clinker used here was made by adding a foaming agent to fine magnesia powder, kneading and molding it, and then
It was calcined at around ℃, and its physical properties are shown in Table 2.

Table 1 Table 2 Table 3 Table 3 shows comparative examples (
11 characteristics are shown. Both bulk specific gravity and cold bending strength are the values after drying at 110°C x 24 hours and 900°C.
The values are shown after firing at ℃×3 hours.

As is clear from Table 3, although the invention product (■) has no difference in bulk specific gravity from comparative example (1), it has a large cold bending strength, and The corrosion loss index (comparative example is set to 100) is significantly smaller.

Furthermore, although there is no difference in the erosion index between the invention product (1) and comparative example (1), the bulk specific gravity is smaller, and it can be seen that the product is lighter in weight. This erosion test uses the rotary slag test method at 1550°C x 4
I went in time. In addition, the slag is a synthetic slag and C/S
=1.5.

[Example-2] The present invention product (Example-1) and the comparative product (1) were coated on the inner surface of a 60-ton tundish in a volume of 15ml1, and the results are shown in Table 4. It showed the same durability as comparative product (1) with a smaller amount of construction.

Table 4 [Effects of the Invention] As described above, when porous magnesia clinker is used as a coating material for containers for molten metal, especially tundishes, the weight can be reduced and the heat insulation properties can be improved.
Seizure with the lining refractories is reduced, making maintenance of the tanditshu easier.

Furthermore, corrosion resistance is improved compared to conventional weight reduction methods, so
It becomes easier to increase the number of steel received. Moreover, since the impurity components are reduced, the possibility of molten steel contamination is also reduced.

As a result, it is effective in improving the billet yield and reducing steel manufacturing costs.

Claims (1)

[Claims] (1) 10 to 50% by weight of porous magnesia clinker
A coating material for metallurgical molten metal containers, the remainder being a general coating material and a binder.