JPH0550188A - Method and apparatus for continuous casting - Google Patents

Abstract

PURPOSE:To obtain method and apparatus for continuous casting, by which cast slab temp. is stabilized in short time under good heat transfer without variance to temp. in width direction of the slab. CONSTITUTION:Into casting space 3 in a graphite mold 2 forming metal thermal- spraying layer 11 in the inner face, molten metal 8 is continuously introduced and cooled with a cooling device 4 to continuously feed the cast slab 10. Wettability and thermal conductivity between the graphite mold 2 and the molten metal, are good, and the temp. in width direction of the slab is made to uniform and the cast slab temp. is stabilized in short time and the cast slab having excellent quality is obtd.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a continuous casting method and apparatus for metals or alloys, and more particularly to a continuous casting method and apparatus suitable for horizontal continuous casting of copper and copper alloy plate ingots.

[0002]

2. Description of the Related Art FIG. 2 is a vertical sectional view showing a conventional continuous casting apparatus for horizontally continuously casting a plate-shaped ingot of copper and a copper alloy. In the figure, 1 is a continuous casting apparatus, 2 is a graphite mold that constitutes this continuous casting apparatus 1, and has a plate-shaped casting space 3 between an upper die 2a and a lower die 2b. 4 is a graphite mold 2
The cooling device made of copper is provided so as to be in contact with the periphery of the water tank, and a water passage for circulating the cooling water is provided, but it is not shown. 5 is a graphite mold 2 and a cooling device 4
Is a steel framework that firmly holds the graphite mold 2 and the cooling device 4 tightly fastened to the iron framework 5 with a large number of bolts (not shown).

6 is a molten metal inlet provided on one side of the casting space 3, 7 is an ingot outlet provided on the opposite side, 8 is a molten metal, 9 is a solidification zone, and 10 is an ingot. The cross-sectional shape of the casting space 3 is formed so as to have substantially the same shape and dimensions as the ingot 10 to be cast.

In the continuous casting method using the continuous casting apparatus 1 described above, while cooling water is circulated in the water passage of the cooling apparatus 4 for cooling, copper is introduced from the molten metal inlet 6 into the casting space 3 of the graphite mold 2.
A molten metal 8 such as a copper alloy is introduced, the solidification is completed through the solidification zone 9, and the generated ingot 10 is sent out from the ingot outlet 7.

In the above continuous casting, in order to obtain a high quality ingot, the melting point of the metal (solidification temperature range in the case of alloy)
It is necessary to cool at an appropriate cooling rate in the vicinity. Further, when the material is rapidly cooled at a cooling rate of usually 30 ° C./sec or more, it becomes a supercooled state, but it is necessary to maintain an appropriate supercooled state. Further, it is necessary to make the temperature of the ingot in the plate width direction uniform. These conditions determine the grain size, quality of segregation, reverse segregation, presence of cracks, other defects, and their degree.

[0006]

However, in the conventional continuous casting apparatus 1, the heat transfer between the graphite mold 2 and the molten metal 8 at the initial stage of casting is poor, so that the cooling rate, the adjustment of the supercooled state and the plate width direction are performed. It is difficult to make the temperature uniform, the crystal grains become large, and defects such as segregation and cracking are likely to occur. The heat transfer between the graphite mold 2 and the molten metal 8 is improved and stabilized with the elapse of casting time, but there was a problem that the stabilization time was long and the quality of the obtained ingot was not constant.

The present invention has been made in order to solve the above problems, and has good heat transfer between the graphite mold and the molten metal, a uniform temperature in the width direction of the plate, and a short time even with the passage of time. It is an object of the present invention to propose a continuous casting method and apparatus which are stable at high temperature and can obtain ingots of excellent quality.

[0008]

The present invention is the following continuous casting method and apparatus. (1) A continuous casting method in which a molten metal is continuously introduced into a casting space of a graphite mold having a metal sprayed layer formed on the inner surface thereof, the molten metal is cooled through the graphite mold, and the resulting ingot is continuously fed. (2) A graphite mold having a casting space for continuously introducing molten metal to generate an ingot, a metal sprayed layer formed on an inner surface of the graphite mold, and a graphite so as to cool the molten metal through the graphite mold. A continuous casting device equipped with a cooling device provided around the mold. (3) The continuous casting apparatus according to (2), wherein the metal sprayed layer is formed on the roughened surface of the inner surface of the graphite mold.

[0009]

In the continuous casting method using the continuous casting apparatus of the present invention, the molten metal is continuously introduced into the casting space of the graphite mold, and the molten metal is solidified by cooling the molten metal through the graphite mold by the cooling device to continuously produce the ingot. Send it out.

As a result of studying the above problems in the conventional continuous casting apparatus, the heat transfer between the graphite mold and the molten metal is poor because the wettability between the graphite mold and the molten metal is poor. It was found that the surface is roughened and the pores are clogged with the molten metal, so that the wettability is improved and the heat transfer is improved and stabilized.

In the continuous casting apparatus of the present invention, since the metal sprayed layer is formed on the inner surface of the graphite mold, the wettability with the molten metal is good, the heat transfer is good, and there is no temperature variation in the plate width direction. The temperature of the graphite mold and the surface temperature of the ingot are stabilized in a short time. Therefore, the obtained ingot has a small crystal grain, is free from defects such as cracking and segregation, and is a uniform and excellent quality ingot.

When the inner surface of the graphite mold is roughened in advance and a metal sprayed layer is formed on this roughened surface, the graphite mold is excellent in holding property with respect to the metal sprayed layer, and heat transfer is further improved.
The stability is further improved.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a vertical sectional view showing a continuous casting apparatus according to an embodiment. In the figure, the same symbols as those in FIG. 2 indicate the same or corresponding parts.

The continuous casting apparatus 1 is similar to that shown in FIG.
For horizontally and continuously casting a plate-shaped ingot of copper and a copper alloy, a cooling device 4 having a water passage (not shown) is provided so as to be in contact with the periphery of a graphite mold 2 having a casting space 3. It is held by the iron framework 5.

Reference numeral 11 denotes an upper mold 2a and a lower mold 2 of the graphite mold 2.
It is a metal sprayed layer formed on the inner surface of b, and is formed on the roughened surface 12 formed beforehand by particle injection such as shot blasting on the inner surface of the upper mold 2a and the lower mold 2b. The surface roughness of the roughened surface 12 is preferably 10 to 80 μm, and the thickness of the metal sprayed layer 11 is preferably 20 to 70 μm. Other configurations are the same as those in FIG.

In the continuous casting method using the above continuous casting apparatus 1, while cooling water is circulated in the water passage of the cooling apparatus 4 to cool it, copper is introduced from the molten metal inlet 6 into the casting space 3 of the graphite mold 2.
A molten metal 8 such as a copper alloy is introduced, the solidification is completed through the solidification zone 9, and the generated ingot 10 is sent out from the ingot outlet 7.

In this case, since the metal sprayed layer 11 is formed on the inner surfaces of the upper mold 2a and the lower mold 2b of the graphite mold 2,
The wettability with the molten metal 8 is good, the heat transfer is good, there is no temperature variation in the plate width direction, and the temperature of the graphite mold 2 and the surface temperature of the ingot 10 are stable over a short time. Therefore, the obtained ingot 10 has a small crystal grain, is free from defects such as cracking and segregation, and is of uniform and excellent quality.

Since the metal sprayed layer 11 is formed on the roughened surface 12 which is obtained by roughening the inner surfaces of the upper mold 2a and the lower mold 2b of the graphite mold 2 in advance, the graphite mold 2 can be retained with respect to the metal sprayed layer 11. Excellent, better heat transfer, improved temperature stability and quality.

In the upper and lower half-split graphite molds 2 for producing ingots of phosphor bronze having a width of 450 mm and a thickness of 15 mm, the dimensions of the ingot forming portions of the upper mold 2a and the lower mold 2b are 450 mm in width, 250 mm in depth and 250 mm in depth. A 7.5 mm piece was masked on both ends in the width direction of 15 mm to roughen the center part to 420 mm by shot blasting, and then copper was sprayed by an ordinary industrial method. The surface roughness before the treatment is 2 μm, and the surface roughness after removing about 0.1 mm by the base treatment is about 30 μm.
m, and the thickness of copper by thermal spraying was about 50 μm.

As a control, a graphite template having only a surface treatment by shot blasting and an untreated one were prepared.

A thermocouple was set in the central portion of the graphite mold 2 in the widthwise direction to a position of 10 mm, 50 mm, and 100 mm from the molten metal side, a thermocouple was set, and the temperature was measured for 10 hours from the start of casting. It was The temperature of the upper surface of the ingot at the outlet was also measured.

With the above horizontal continuous casting apparatus, the casting temperature (holding furnace temperature) is 1200 ° C., the casting speed (average index speed)
As a result of continuous casting at 160 mm / min, the untreated one did not stabilize for more than 5 hours, but the one with only the base treatment stabilized in about 2 hours, and the one subjected to copper spraying took less than 1 hour. Stabilized. As a result of investigating the macrostructures of the vertical section, the upper surface, and the lower surface of the ingot, it was found that the ingot macrostructure was coarse when the temperature at the points of 10 mm and 50 mm from the molten metal side was high, and fine when the temperature was low.

In the above description, the metal sprayed layer 1
1 is preferably the same kind as the metal or alloy to be cast, but may be another. In this case, the metal sprayed layer is partially replaced with the molten metal, but since the amount is small, it does not affect the quality of the ingot.

Further, although the above embodiment has been described with respect to the example of casting of copper or copper alloy, it can be similarly applied to other metals or alloys.

[0025]

EFFECTS OF THE INVENTION According to the continuous casting method of the present invention, since the casting is performed using the graphite mold having the metal sprayed layer, the heat transfer between the graphite mold and the molten metal is good, and the temperature in the plate width direction is high. Is uniform, the ingot temperature stabilizes in a short time even over time,
Ingots of excellent quality can be produced.

According to the continuous casting apparatus of the present invention, since the metal sprayed layer is formed on the inner surface of the graphite mold, the continuous casting apparatus suitable for continuous casting as described above can be easily obtained.

According to the continuous casting apparatus in which the inner surface of the graphite mold is roughened to form the metal sprayed layer, the heat transfer property is further excellent and the stability is further improved.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing a continuous casting apparatus according to an embodiment.

FIG. 2 is a vertical cross-sectional view showing a conventional continuous casting device.

[Explanation of symbols]

 2 graphite mold 3 casting space 4 cooling device 5 iron frame 8 molten metal 9 solidification zone 10 ingot 11 metal sprayed layer 12 roughened surface

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[Procedure amendment]

[Submission date] December 3, 1991

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be amended] Claims

[Correction method] Change

[Correction content]

[Claims]

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0008

[Correction method] Change

[Correction content]

The present invention is the following continuous casting method and apparatus. (1) Sprayed layer of metal or alloy on the inner surface (hereinafter, simply metal
A continuous casting method in which a molten metal is continuously introduced into a casting space of a graphite mold in which a sprayed layer is formed, the molten metal is cooled through the graphite mold, and the resulting ingot is continuously fed. (2) A graphite mold having a casting space for continuously introducing molten metal to generate an ingot, a metal sprayed layer formed on an inner surface of the graphite mold, and a graphite so as to cool the molten metal through the graphite mold. A continuous casting device equipped with a cooling device provided around the mold. (3) The continuous casting apparatus according to (2), wherein the metal sprayed layer is formed on the roughened surface of the inner surface of the graphite mold.

Claims (3)

[Claims] 1. A molten metal is continuously introduced into a casting space of a graphite mold having a metal sprayed layer formed on its inner surface, the molten metal is cooled through the graphite mold, and the ingot produced is continuously fed out. Continuous casting method. 2. A graphite mold having a casting space for continuously introducing molten metal to generate an ingot, a metal sprayed layer formed on an inner surface of the graphite mold, and cooling the molten metal through the graphite mold. And a cooling device provided around the graphite mold, the continuous casting device. 3. The continuous casting apparatus according to claim 2, wherein the metal sprayed layer is formed on the roughened surface of the inner surface of the graphite mold.