JPH06220517A - Sleeve brick for steel tapping hole in converter - Google Patents

Abstract

PURPOSE:To provide a sleeve brick for steel tapping hole in a converter, in which heat shock resistance and oxidizing resistance are improved without lowering erosion resistance and by these resistance, the wear resistance and the durability can be improved. CONSTITUTION:In the magnesia-graphite quality sleeve brick for steel tapping hole in the converter, chromium alloy steel fibers are added at 0.1-20wt% to 60-90wt% magnesia, 5-35wt% graphite and 1-10 wt% Al powder, and organic binder or tar pitch is added at 3-5wt%, and kneaded and formed to manufacture the sleeve brick. By this method, the spalling resistance, the oxidizing resistance and the erosion resistance are drastically improved and in comparison with the ordinary product, this brick shows 0.5 of the erosion ratio and 0.7 of the oxidizing ratio.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a converter outlet steel sleeve sleeve brick, and particularly improves thermal shock resistance and oxidation resistance without lowering corrosion resistance, thereby enhancing wear resistance and service life. The present invention relates to a converter steel outlet sleeve brick.

[0002]

2. Description of the Related Art In recent years, magnesia-carbon bricks have come to be widely used for converter exit tap sleeve bricks because of their excellent corrosion resistance and thermal shock resistance.

However, magnesia carbon bricks are
In addition to the drawback that carbon disappears under an oxidizing atmosphere, it is disadvantageous in increasing mechanical strength and wear resistance due to the properties of graphite, which is the main carbon source,
At the tapping port of the converter, oxidative damage is particularly large, wear due to the molten steel flow is likely to occur, and this is one of the causes of shortening the life.

[0004]

In order to improve the wear resistance of magnesia carbon, it has been proposed to add carbon fiber or the like to metal powder of aluminum, silicon, magnesia, calcium or the like. In the case of powder, the brick becomes stiff after heating, the thermal shock resistance is lowered, and preceding wear of joints is likely to occur.

Further, carbon fibers are difficult to disperse when they are manufactured, and even if they are manufactured, their mechanical strength is low.

[0006]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that in order to improve the wear resistance and the durability of a magnesia carbonaceous converter tap sleeve sleeve brick,
It was found that it is necessary to add an antioxidant in place of the metal powder or the like, which does not lower the thermal shock resistance and improves the oxidation resistance.

[0007] Then, various development studies are conducted, and Example 1 is carried out.
As a result of conducting an oxidation test considering the composition as shown in, it was found that the composition using the chromium alloy steel fiber has very excellent oxidation resistance.

However, if the weight percentage of metal Cr in the chromium alloy steel fiber is 9% or less, rust is likely to occur and the effect of preventing oxidation becomes small. When the diameter of the chromium alloy steel fiber is 0.4 m / m or more, the volume ratio of the fiber in the matrix becomes small, the antioxidant effect is reduced, and the thermal shock resistance is also reduced. On the other hand, when the diameter of the chromium alloy steel fiber is smaller than 0.1 m / m, the effect of preventing oxidation is improved, but the thermal shock resistance is reduced as in the case of metal powder. The cross-sectional shape may be a polygon such as a triangle, a rectangle, a circle, or an ellipse. About the addition amount 2
If it exceeds 0%, the ratio of fibers in the matrix becomes too large, and the performance as a refractory material deteriorates.
The improvement in thermal shock resistance is not remarkable.

Further, the fiber length is 2 mm.
When it is less than 30 mm, the thermal shock resistance is deteriorated, and when it is 30 mm or more, the kneading work becomes difficult and good quality cannot be obtained.

[0010]

EXAMPLES Table 1 shows the compounding compositions of Examples 1 to 3 of the present invention and Comparative Examples 4 to 10. In both cases, the compounds of each composition were mixed and kneaded, and this was molded by isostatic pressing, and 40 mm x 4
A sample was prepared by processing into a shape of 0 mm × 200 mm.

The evaluation test results are shown in Table 2.

[0012]

[Table 1]

[0013]

[Table 2]

[0014]

As described above, magnesia 60 to 90% by weight, graphite 5 to 35% by weight, Al powder 1 to 10% by weight, chromium alloy steel fiber cross section 0.1 to 0.4 mm, length 2
Magnesia graphitic converter steel outlet sleeve brick manufactured by adding 0.1 to 20% by weight of -30 mm and 3 to 5% of organic binder, kneading and molding, has spalling resistance and oxidation resistance. Corrosion resistance was greatly improved, and as shown in Table 2, the melting loss ratio was less than that of the conventional product (Comparative Example 10).
5. The oxidation resistance ratio was 0.7.

Claims (2)

[Claims] 1. A magnesia-graphite converter core tap sleeve brick having a magnesia content of 60 to 90% by weight and a graphite content of 5%.
.About.35% by weight, Al powder 1 to 10% by weight, and chromium alloy steel fiber 0.1 to 20% by weight added to the organic binder or tar. A converter outlet tap sleeve brick manufactured by adding 3 to 5% by weight of pitch and kneading and molding. 2. A chromium alloy steel fiber contains 9% metal Cr.
% Or more, the cross section is a polygon with a side length of 0.1 to 0.4 mm or a circle with a diameter of 0.1 to 0.4 mm, an ellipse with a length of 2 to 30 mm.
The converter outlet tap sleeve brick according to claim 1, wherein