JPH06297103A - Mold for continuous casting - Google Patents

Abstract

(57) [Summary] [Object] To provide a continuous casting mold capable of producing a high-quality product by making the thickness of the solidified shell uniform and preventing cracks in the slab in continuous casting. [Structure] A mold used for continuous casting using powder, in which a plurality of irregularities having a diameter of 0.1 to 3 mm and a depth of 5 to 300 μm are uniformly provided on the inner surface of the mold 1. The unevenness is a circular or elliptical unevenness provided by etching,
Alternatively, the projections and depressions are provided by shot blasting.
The position where the unevenness is formed is 20 to 150 mm from the surface of the molten metal.
Is preferred.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a continuous casting mold used for continuous casting of metal.

[0002]

2. Description of the Related Art Conventionally, a copper casting mold or a Ni-Cr plated copper casting mold has been used as a continuous casting mold used for continuous casting of metal. Further, the inner surface of the mold is smooth. The solidified state of molten steel during continuous casting using a conventional mold will be described with reference to FIGS. 4 to 6. Figure 4
Is a perspective view showing a part of a conventional continuous casting mold, FIG. 5 is an explanatory view showing the shape of the inner surface of the mold, and FIG. 6 is a sectional view of the mold.

When the molten steel 52 is poured into the mold 51, the powder 53 is interposed on the upper portion of the molten steel 52, and the upper portion of the powder becomes the unmelted layer 53a, and the powder 53 in contact with the molten steel 52 becomes the molten powder 53b. It flows along the inner surface of the mold 51 and functions as a lubricant between the mold 51 and the molten steel 52. Further, a powder fixing layer 53c is formed on the inner surface of the mold 51 where the powder 53 contacts the mold 51.

[0004]

However, in the above-described conventional mold 51, the powder 53 is partially rapidly cooled because the inner surface of the mold 51 is smooth at the portion where the molten steel 52 solidifies, and the uneven thickness is not uniform. The powder fixing layer 53c is formed. Therefore, the thickness of the solidified shell 54 becomes non-uniform, or the cast piece is cracked, which deteriorates the quality of the product.

The present invention has been proposed in view of the above-mentioned problems, and an object thereof is to provide a high quality product by making the thickness of the solidified shell uniform and preventing the slab from cracking in continuous casting. The object is to provide a continuous casting mold capable of producing

[0006]

The continuous casting mold of the present invention is a mold used for continuous casting using powder, and has a diameter of 0.1 at the portion where the powder fixing layer is formed on the inner surface of the mold.
A plurality of irregularities having a depth of 3 mm and a depth of 5 to 300 μm are uniformly provided.

At this time, the irregularities are circular or elliptical irregularities provided by etching.

Alternatively, the irregularities are circular or oval irregularities provided by shot blasting. Alternatively,
The irregularities are circular or elliptical irregularities provided by laser processing.

[0009]

According to the present invention, a plurality of irregularities are uniformly provided on the inner surface of the mold as described above. The unevenness is provided in a range of 20 to 150 mm below the surface of the molten metal on the inner surface of the mold, and is provided at a position suitable for forming the powder fixing layer.

The powder fixing layer formed between the mold and the shell due to the unevenness positively forms a small thickness unevenness, so that a large thickness unevenness of the powder fixing layer, which is a bad influence at the time of shell formation, is formed. To eliminate. Therefore,
Since the thickness of the solidified shell can be made uniform, it is possible to prevent cracks in the slab to be produced and to provide a high quality product.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. 1 is a perspective view showing a part of the surface of a continuous casting mold according to the present invention, FIG. 2 is an explanatory view showing the shape of the inner surface of the mold,
FIG. 3 is a sectional view of the mold.

The size of the mold 1 according to this embodiment has a width of 1
A copper alloy having a thickness of 200 mm and a thickness of 230 mm is used. The inner surface of the mold 1 is about 20 to 1 from the top of the inner surface.
A plurality of irregularities 5 are uniformly provided in the vicinity of 50 mm. The unevenness 5 has a diameter of 0.1 to 3 mm and a depth of 5 to 30.
It is 0 μm.

As a method for providing the unevenness 5, photo-etching, shot blasting, laser processing or the like is used.

The diameter and depth of the unevenness 5 are obtained by experiments, and the experimental conditions and results are shown below. Table 1 shows the types of molten steel used in the experiments, Table 2 shows the experimental conditions, and Table 3 shows the experimental results.

[0015]

[Table 1]

[0016]

[Table 2]

[0017]

[Table 3]

As shown in the above experimental results, the unevenness has a diameter of 0.1 to 3 mm and a depth of 5 to 300 μm.
In the case of, the properties of the slab produced were good. On the other hand, in the range other than this range, the quality of the product was remarkably deteriorated, such as the occurrence of vertical cracks in the slab.

A method for producing a slab using the above continuous casting mold 1 will be described. Molten steel 2 is carried by a tundish or the like and poured into a continuous casting mold 1. Then, the powder 3 is put on the molten steel 2 poured into the mold 1. The upper part of the powder 3 is the unmelted layer 3
The powder 3 which has become a and is in contact with the molten steel 2 flows as molten powder 3b along the inner surface of the mold 1 and functions as a lubricant between the mold 1 and the molten steel 2.

The molten steel 2 in the mold 1 is cooled by the mold 1 and a solidified shell 4 is formed on the surface. Further, the powder fixing layer 3c having a substantially uniform thickness is formed at the position where the unevenness 5 is formed on the inner surface of the mold 1. This powder fixing layer 3c
The position at which is formed varies depending on the casting speed and the like, but according to experiments by the present inventors, it is formed within a range of 20 to 150 mm from the molten metal surface. Therefore, a plurality of irregularities 5 were formed on the inner surface of the mold 1 within this range.

[0021]

As described above, according to the present invention, a plurality of irregularities are uniformly formed on the inner surface of the mold as described above.
Therefore, since the powder fixing layer becomes uniform and the thickness of the solidified shell can be made uniform, it is possible to prevent cracking of the cast slab to be manufactured and to provide a high quality product.

[Brief description of drawings]

FIG. 1 is a perspective view showing a part of a continuous casting mold according to the present invention.

FIG. 2 is an explanatory view showing a surface shape of an inner surface of a continuous casting mold.

FIG. 3 is a sectional view of a continuous casting melt mold.

FIG. 4 is a perspective view showing a part of a conventional continuous casting mold.

FIG. 5 is an explanatory view showing a surface shape of an inner surface of a conventional continuous casting mold.

FIG. 6 is a cross-sectional view of a conventional continuous casting mold.

[Explanation of symbols]

 1 Mold 2 Molten Steel 3 Powder 3a Powder Fixing Layer 4 Solidification Shell 5 Concavo-convex 51 Mold 52 Molten Steel 53 Powder 53a Powder Fixing Layer 54 Solidification Shell

[Procedure amendment]

[Submission date] November 17, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0012

[Correction method] Change

[Correction content]

As the size of the mold 1 according to the present embodiment, a mold made of copper alloy having a width of 1200 mm and a thickness of 230 mm is used. On the inner surface of the mold 1, a plurality of irregularities 5 are uniformly provided in the vicinity of about 20 to 150 mm from the upper portion of the inner surface. The unevenness 5 has a diameter of 0.1 to 3 mm and a depth of 5 to 300 μm.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] Explanation of code

[Correction method] Change

[Correction content]

[Explanation of symbols] 1 mold 2 molten steel 3 powder 3a powder unmelted layer 3b molten powder layer 3c powder fixed layer 4 solidification shell 5 unevenness 51 mold 52 molten steel 53 powder 53a powder unmelted layer 53b molten powder layer 53c powder fixed layer 54 solidification shell

[Procedure 3]

[Document name to be amended] Statement

[Name of item to be corrected] 0015

[Correction method] Change

[Correction content]

[0015]

[Table 1]

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Shigeaki Ogibayashi 20-1 Shintomi, Futtsu City, Chiba Shin Nippon Steel Co., Ltd. Central Research Division

Claims (4)

[Claims] 1. A mold used for continuous casting using powder, the diameter of which is 0.1 to 3 at the portion where the powder fixing layer is formed on the inner surface of the mold.
A casting mold for continuous casting, characterized in that a plurality of irregularities having a depth of 5 mm and a depth of 5 to 300 μm are uniformly provided. 2. The continuous casting mold according to claim 1, wherein the irregularities are circular or oval irregularities provided by etching. 3. The continuous casting mold according to claim 1, wherein the irregularities are circular or oval irregularities provided by shot blasting. 4. The continuous casting mold according to claim 1, wherein the irregularities are circular or oval irregularities provided by laser processing.