JPS63188460A - Perfect sealing method for tundish inside - Google Patents

Abstract

PURPOSE:To prevent the generation of the oxide inclusion of a casting by completely closing the space between a tundish main body and cover and blowing an Ar gas into the tundish immediately after raising the heat of a gas burner as well. CONSTITUTION:The space between a tundish main body 1 and covers 2, 3 is closed by interposing a castable or ceramic fiber, etc., therein. The cover 6 and pipe 5 for the opening part 4 of an Ar gas blowing pipe 5 are integrally formed to seal the space between the tundish main body 1 and the cover 6 similarly as well. Initially the tundish 1 is subjected to a heat-up by blowing the gas for heating from the opening 4, which is closed by the cover 6 by fitting the pipe 5 simultaneously with completion of the heat-up and the blowing of the Ar gas is performed. Owing to the Ar gas being blown by sealing the space between the main body 1 and covers 2, 3, 6 the tundish inside becomes a reducing atm. completely. Consequently the generation of the oxide inclusion of the casting is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for completely sealing the inside of a tundish for continuous casting of molten steel.

[Prior Art] Conventionally, in a tundish for continuous casting, after heating up before casting is completed and immediately before starting casting, Ar gas is blown into the tundish body 1 through the burner opening 4 shown in FIG. 4 to create a reducing atmosphere. I was trying to replace it with . In this case, gaps were present at the joints between the inspection opening lid 2, the stopper opening lid 3, etc., and the tundish body 1 due to adhesion of base metal, wear, etc.

[Problems to be solved by the invention] For these reasons, the inside of the tundish becomes an oxidizing atmosphere after the heating and before the Ar gas is blown into the tundish, making it impossible to completely replace the inside of the tundish with a reducing atmosphere at the start of casting. , inclusions were generated at the bottommost part of the continuous casting material.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for completely sealing the inside of a tundish, which can solve the above problems.

[Means and operations for solving the problem] The method of completely sealing the inside of the tundish of the present invention completely seals the space between the tundish body and the lid, and also seals the inside of the tundish as soon as the heating is completed after heating with a gas burner. Argon gas is blown into the tank.

The space between the tundish body and the lid is completely sealed.
During heating, combustion gas creates a reducing atmosphere inside the tundish. Then, since Ar gas is blown into the tundish at the same time as the burner is extinguished upon completion of heating, the inside of the tundish can be completely maintained in a reducing atmosphere.

[Example] An example of an apparatus for carrying out the present invention will be described with reference to FIG. A castable or ceramic fiber or the like is interposed between the main body 1 and the lid 2.3 to seal it. Reference numeral 5 denotes an Ar gas blowing pipe, to which a lid 6 of the burner opening 4 is integrally attached, and the space between this lid and the tundish body is sealed in the same manner as described above.

Then, after heating the tundish by blowing gas through the opening 4,
As shown in FIG. 2, the Ar gas pipe 5 is immediately attached, the opening 4 is closed with the lid 6, and the blowing of Ar gas is started. Ar
1. Move the tundish while blowing gas, and start injecting 6 minutes after extinguishing the burner.1. Stop blowing Ar gas. In this case, the interior of the tundish is completely replaced with Ar gas by blowing Ar gas into the space between the tundish body and the lid for 6 minutes in a sealed state, and the oxygen concentration within the tundish becomes almost zero.

Here, the state of change in oxygen concentration in the conventional method will be explained with reference to FIG. Approximately 5 minutes after the burner was extinguished, the tundish was moved and the blowing of Ar gas was started. and about 3
Pouring of hot water starts after a minute has elapsed. In this case, the degree of mumminess is approximately 16% while the tundish is being moved. Even at the start of pouring, gas replacement is not performed sufficiently due to gas leakage from the burner opening 4, and the oxygen concentration is 12 to 13%. As a result, inclusions were generated at the bottom of the cast material, and the yield of first-class products was about 93%. On the other hand, in the case of the method of the present invention, as mentioned above, the inside of the tundish can be completely reduced to a reducing atmosphere at the start of casting, so the generation of inclusions can be prevented and the yield of first-grade products can be 100%. did it.

[Effects of the Invention] The present invention is as described above, and the inside of the tundish can be completely reduced to a reducing atmosphere during casting. Thereby, it is possible to prevent the occurrence of oxide inclusions at the bottommost portion of the cast material.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing an example of an apparatus for carrying out the method of the present invention, FIGS. FIG. 4 is an explanatory diagram of a conventional device. 1... Tundish body, 2.3.6... Lid, 4.
...Burner opening, 5...Ar gas pipe. Applicant's agent Patent attorney Takehiko Suzue Figure 1 reduction 4゛

Claims (1)

[Claims] In addition to completely sealing the space between the tundish body and the lid,
A method for completely sealing the inside of the tundish, which is characterized by blowing Ar gas into the tundish at the same time as the heating is completed after heating with a gas burner.