JPH0933174A - EBT refractory - Google Patents

Abstract

(57) [Summary] [Purpose] To provide an EBT wear ring tube in which mechanical wear due to initial spall and molten steel flow is suppressed and its durability is extended. [Structure] The wear ring tube of the inner peripheral portion is integrally formed, and the inner peripheral surface of the wear ring tube is coated with an unshaped refractory material having residual expansiveness. [Effect] By coating the inner surface of the EBT wear ring tube with residual expansive amorphous refractory, mechanical wear due to initial spall of the wear ring tube and molten steel flow is suppressed, and durability is improved as shown in the examples. it can.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an EBT refractory material which suppresses mechanical wear due to an initial spall and molten steel flow caused by the current non-preheating and extends its service life.

[0002]

2. Description of the Related Art Conventionally, in EBT refractories, the wear ring tube is the most worn by the molten steel flow. At present, the main cause of EBT refractory waste is the small amount of wear ring tube remaining. It is due to.
This wear ring tube is formed by being integrally molded.

[0003]

The EBT refractory containing the wear ring tube is used without preheating. Therefore, the molten steel temperature is 1500 to 1650 ℃
There is a difference in temperature, and when the steel is tapped from the electric furnace, an initial spall is generated on the operating surface of the wear ring tube due to the thermal shock. At present, there is no sufficient method for suppressing the initial spall due to heat shock when used without preheating, which causes the wear ring tube to have a reduced service life, which in turn causes a reduction in the EBT refractory. In addition, due to the rise of tapping temperature and shortening of tapping time, the conventional wear ring tube structure has not been able to sufficiently cope with the severe melting loss. SUMMARY OF THE INVENTION It is an object of the present invention to provide an EBT wear ring tube in which these problems of the related art are solved, mechanical wear due to an initial spall and molten steel flow is suppressed, and its durability is extended.

[0004]

In order to achieve this object, the present invention has the following configuration. That is, according to the present invention, 5 m / m to 30 is applied to the inner peripheral surface (molten steel passage surface) of the wear ring tube whose inner peripheral portion is integrally formed.
It is characterized by being coated with an amorphous refractory having a residual expansion property with a thickness of m / m. Amorphous refractory having residual expansiveness used here is residual expansive sillimanite, containing sillimanite group minerals such as andalusite and kyanite, the remainder being high refractory powder such as alumina and alumina as a binder. The thing containing cement is desirable. And the reason for using the amorphous refractory with residual expansion is to suppress the initial spall of the wear ring tube by compressing the wear ring tube by expanding the coating layer, but not only that, the coating layer itself It also has the meaning of suppressing melting loss due to wear of the molten steel flow. In addition, when using sillimanite group minerals, these minerals form crystals with low thermal conductivity such as mullite due to the heat of molten steel, so that the wear ring tube covered by them is not directly subjected to thermal shock from molten steel. This is because The above-mentioned irregular refractory coating method is iron coating, hand coating,
It can be done by spraying, casting, etc., but the reason why the coating thickness is 5 m / m to 30 m / m is that the coating effect does not appear sufficiently at 5 m / m or less, and the inner hole of the wear ring tube at 30 m / m or more. This is because it is considered that not only does it affect the flow rate of molten steel but also the flaking of irregular shaped refractory due to an increase in the frictional force of the molten steel flow.

[0005]

Example 1 Inner diameter 200 m / m of an electric furnace having a capacity of 140 t
No. shown in Table 1 on the inner peripheral surface of the EBT wear ring tube. 15 m / m thick when cast by casting 1 amorphous refractory
Was coated.

[0006]

[Embodiment 2] Inner diameter 200 m / m of an electric furnace having a capacity of 120 t
No. in Table 1 is attached to the inner peripheral surface of the EBT wear ring tube of. Two
The unshaped refractory material shown in 1 was cast at a thickness of 20 m / m.

[0007]

[Table 1]

[0008]

[Effects of the Invention] When the product constructed according to Example 1 was put into practical use, the total service life was 210 ch compared to 140 ch when the conventional amorphous refractory was not coated.
Was the number of times of service. In the case of Example 2, the total service life is 1
When it was 80 ch, according to the second embodiment of the present invention,
A service life of 270 ch was obtained. The present invention coats the inner surface of the EBT wear ring tube with a residual expandable amorphous refractory material to suppress the mechanical wear due to the initial spall of the wear ring tube and the flow of molten steel, thus improving the durability as shown in the examples. However, it has an excellent effect.

Claims (1)

[Claims] 1. An EBT characterized in that the wear ring tube of the inner peripheral portion is formed as an integrated product, and the inner peripheral surface of the wear ring tube is coated with an unshaped refractory material having residual expansiveness.
Refractory.