JPH10195523A - Porous plug - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate interruption of refining caused by melting of a gas introducing pipe by fitting a protecting pipe for electric insulation to the gas introducing pipe in a porous plug. SOLUTION: In the porous plug 2 arranged to a tuyere brick 1 at the bottom part of a molten metal vessel, it is blocked by the protecting pipe 6 for electric insulation that the gas introducing pipe 3 is brought into contact with a plug holding metal 4 and the bottom iron shell 5 of the vessel. By this constitution, the gas introducing pipe 3 and the porous holding metal 4 are surely insulated. In the case, the side surface iron shell of the porous plug 2 is electrically conducted by inserting and conducting an electrode into the molten metal at the time of refining, the melting of the gas introducing pipe 3 is not caused because the gas introducing pipe 3 and the holding metal 4 are blocked. The protecting pipe 6 for electric insulation can easily be taken off from the gas introducing pipe 3, and can be fitted to the plug taken off and set at the time of changing the plug, too, and for the material, Al2 O3 quality ceramic is used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a porous plug for blowing gas for stirring molten metal, which is attached to a ladle for metallurgy.

[0002]

2. Description of the Related Art Conventionally, in refining molten metal, a porous plug is used to blow gas. When a gas is blown into a molten metal, the porous plug has low durability due to back attack of the gas and abrasion and erosion due to convection of the molten metal, so that the porous plug needs to be replaced. The porous plug is replaced by a method such as donning or pulling out. However, since the tip (sintered portion) of the porous plug remains in the tuyere brick inner hole, a thickness of 0. 6-2.
It has become common to wind a 0 mm iron plate.

[0003]

When an iron plate is wound around the entire outer peripheral portion of the porous plug, when the electrode is inserted into the molten metal at the time of refining and the power is supplied, the side steel is conductive, and the gas introduction pipe and the porous press fitting are connected. When they came in contact with each other, there was a case where a short circuit occurred and the gas introduction pipe was melted, making refining impossible. Therefore, as a countermeasure, an electric insulating tape was sometimes wound around the gas introduction pipe. However, the electrical insulating tape may be damaged by the shock at the time of setting, the heat of the molten metal, or the like, so that the insulating tape may not sufficiently serve as an insulator. SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems and to provide a porous plug equipped with a protective pipe for electrical insulation, which enables an iron plate to be wound on the side of a porous plug for gas injection.

[0004]

In order to achieve this object, the present invention has the following arrangement. That is, the electric insulating pipe according to the present invention will be described with reference to FIG.
Porous plug 2 on tuyere brick 1 at the bottom of molten metal container
The gas inlet pipe 3 is in contact with the plug holder 4 or the bottom shell 5 of the container.
As a result, the gas introduction pipe 3 and the porous holding member 4 could be reliably insulated. The electric insulation protection pipe 6 can be easily detached from the gas introduction pipe 3, and can be detached when replacing the porous plug 2 and attached to a plug to be set. As the material, an electrically insulating and protective pipe made of ceramics mainly composed of Al ₂ O ₃ ceramics and SiO ₂ was used.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Conventionally, an electric insulating tape was wrapped around a gas introduction pipe to prevent conduction. However, each time a porous plug was used, it was necessary to change the electric insulating tape. However, when the electric insulating protection pipe made of Al ₂ O ₃ ceramics of the present invention was used as shown in FIG. 1, there was no trouble such as smelting impossible due to conduction at the time of energization, and the porous plug was used smoothly up to 5 ch which is the life of the porous plug. After use, the electrically insulated protective pipe was sound and continued to be used for two more porous plugs.

[0006]

According to the present invention, by using an electrically insulating and protective pipe, the electrode is inserted into the molten metal at the time of refining and electricity is supplied, so that the gas introduction pipe and the holding metal can be electrically connected even if the side shell of the porous plug becomes conductive. It was blocked by the insulating protection pipe, and the smelting impossible due to the melting of the gas introduction pipe was eliminated.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a used state of a porous plug to which a protective pipe for a porous plug of the present invention is mounted.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Tuyere brick 2 Porous plug 3 Gas introduction pipe 4 Porous presser fitting 5 Bottom steel 6 Electric insulation protection pipe

Claims (1)

[Claims] 1. A porous plug characterized in that a protective pipe for electrical insulation is mounted on a gas introduction pipe of a porous plug for gas injection.