KR20170100221A - Direct chill casting for grain refiment of microstructure - Google Patents

Abstract

The present invention relates to a direct cool-casting device. More specifically, the present invention relates to the direct cool-casting device applying an ultrasonic wave to molten metal in a case of direct cool-casting and applying mechanical vibration in a step of solidifying the molten metal to refine a structure in order to significantly improve a quality of casting. The present invention comprises: a tundish; a cooling mold; a driving rod; and an ultrasonic vibration device.

Description

Technical Field [0001] The present invention relates to direct chill casting for grain refinement,

The present invention relates to a direct cooling casting apparatus, and more particularly, to a direct cooling casting apparatus capable of greatly improving the quality of a casting product by microwaving a texture by applying mechanical vibration to a molten metal during direct cooling casting, .

A direct cooling casting machine is a continuous casting machine, which is capable of continuously casting a solid metal by directly cooling the molten metal.

FIG. 1 shows a conventional direct cooling casting apparatus. Referring to FIG. 1, a conventional direct cooling casting apparatus includes a tundish 10, a cooling mold 20, and a movable stand 30.

The tundish 10 provides the molten metal 1 to the cooling mold 20 at a suitable flow rate, which is stored as a storage device in which the molten metal 1 can be poured.

When the molten metal 1 is supplied from the turn-dish 10, the cooling mold 10 cools the molten metal 2 in a liquid state with the solid metal 4 to cast the product.

1 shows that the cooling mold 10 cools the molten metal 2 in a liquid state with solid metal using cooling water. However, the cooling mold 10 is not limited to the water-cooling type, Can be solidified.

Also, between the molten metal (2) and the solid metal (4), there exists a solid-liquid coexistence region (3, Mushy Zone) in which the molten metal (2) and the solid metal (4) coexist.

The movable table 30 is provided below the cooling mold 10 and moves downward for continuous casting of the solid metal 4 as a pedestal on which the solid metal 4 is placed.

That is, the movable base 30 continuously obtains the casting product by continuously removing the solid metal 4 solidified in the cooling mold 10.

On the other hand, in the molten metal 2, the outer portion (b) solidifies faster than the inner portion (a), and due to the difference in solidification speed, inhomogeneous crystal grains are generated in the inner portion (a) There is a problem of deteriorating the quality of the casting.

It is an object of the present invention to provide a direct cooling casting apparatus capable of producing a high-quality casting product by homogenizing fine grains by performing refinement of crystal grains during direct cooling casting will be.

Another object of the present invention is to provide a direct cooling casting apparatus capable of further improving the quality of castings by performing grain refinement work on each of molten metal and solid metal.

In order to accomplish the above object, the present invention provides a tundish which is supplied with molten metal and poured into a cooling mold at a predetermined flow rate; A cooling mold for solidifying the molten metal poured from the tundish into a solid metal state from a liquid state; A movable base provided below the cooling mold and solidified in the cooling mold to move up and down to allow the solid metal to be continuously cast; And an ultrasonic vibrator disposed inside the cooling mold for contacting the molten metal and performing an operation of stirring the molten metal and refining the grain by outputting an ultrasonic wave by receiving power, .

In a preferred embodiment, the movable table is provided with vibrating means for refining the crystal grains of the solid metal and refining the process texture.

In a preferred embodiment, the vibration means is provided as a motor for vibrating the movable base.

In a preferred embodiment, the ultrasonic vibration apparatus is formed of a piezoelectric ceramics.

In a preferred embodiment, the piezoelectric ceramics are provided in the cooling mold.

The present invention has the following excellent effects.

First, according to the direct cooling casting apparatus of the present invention, it is possible to provide a cast product having homogeneous and fine crystal grains by performing grain refining operation in direct cooling casting.

Further, according to the direct cooling casting apparatus of the present invention, the molten metal is stirred and grain refinement is performed by an ultrasonic vibrator, and the solid metal is micronized by the physical vibration by the motor and the process microstructure is made very homogeneous There is an advantage that a cast product having fine crystal grains can be provided.

1 is a view showing a conventional direct cooling casting apparatus,
2 is a view showing a direct cooling casting apparatus according to an embodiment of the present invention.

Although the terms used in the present invention have been selected as general terms that are widely used at present, there are some terms selected arbitrarily by the applicant in a specific case. In this case, the meaning described or used in the detailed description part of the invention The meaning must be grasped.

Hereinafter, the technical structure of the present invention will be described in detail with reference to preferred embodiments shown in the accompanying drawings.

However, the present invention is not limited to the embodiments described herein but may be embodied in other forms. Like reference numerals designate like elements throughout the specification.

2, a direct cooling casting apparatus according to an embodiment of the present invention includes a tundish 100, a cooling mold 200 A movable base 300, and an ultrasonic vibration device 400, and may further include a vibration means 500.

The tundish 100 provides molten metal 1, which is stored as a storage device in which the molten metal 1 can be poured, to the cooling mold 20 to be described below at a suitable flow rate.

Although not shown, the tundish 100 may be provided with a refining apparatus for refining.

In addition, the turn-dish 100 may further include a temperature controller that can maintain the temperature of the molten metal 1 at a predetermined temperature.

Although the shape of the turn-dish 100 is generally determined according to the state of the casting facility arrangement of the performance plant, it is generally designed to have a shape maximizing the residence time of the molten metal 1 for floating separation of inclusions desirable.

The cooling mold 200 receives the molten metal 1 from the tundish 100 and solidifies the molten metal 2 in a liquid state by cooling the solid metal 4.

The cooling mold 200 solidifies the molten metal 2 by using the cooling water 210 in a water-cooled manner.

However, the cooling mold 200 can cool the molten metal 2 in an air-cooled manner.

The movable table 300 is provided below the cooling mold 200 and moves downwardly for continuous casting of the solid metal 4 as a pedestal on which the solid metal 4 is placed.

That is, the movable base 300 continuously obtains the casting product by continuously removing the solidified metal 4 solidified in the cooling mold 10.

2, the movable base 300 is provided below the cooling mold 200 and moves downward. However, the solid metal 4 solidified in the cooling mold 10 is drawn out laterally .

That is, the direct cooling casting apparatus according to an embodiment of the present invention can produce castings by a vertical semi-continuous casting method.

The ultrasonic vibration device 400 is disposed inside the cooling mold 200 and is in contact with the molten metal 2 to supply ultrasonic waves to the molten metal 2 so that the molten metal 2 is agitated and refined .

The ultrasonic vibration device 400 is spaced apart from the cooling mold 200 and can be locked to the molten metal 2 and attached to the inner surface of the cooling mold 200 to be in contact with the molten metal 2 have.

That is, there is no particular restriction as long as the installation position of the ultrasonic vibration device 400 is in contact with the molten metal 2.

In addition, the ultrasonic vibration device 400 may be a piezoelectric ceramic that vibrates when power is applied from the outside to generate ultrasonic waves.

In addition, the piezoelectric ceramics can adjust the intensity of the ultrasonic wave by changing the frequency of the electric current, so that it is suitable for refining the crystal grains by stirring the molten metal.

The ultrasonic vibration device 400 also stirs the molten metal 2 to reduce the temperature difference between the outside of the cooling mold 20 and the inside of the center.

This allows the solidification rate of the molten metal (2) to be uniformly controlled as a whole to homogenize and miniaturize the crystal grains.

In addition, the present invention may further include a vibrating means 500, wherein the vibrating means 500 applies a predetermined vibration to the solid metal 4 to perform grain refinement and process texture refinement.

That is, the vibrating means 500 is a device for performing crystal refinement secondary to the ultrasonic vibration device 400.

The vibration unit 500 may be a motor that applies mechanical vibration to the movable base 300.

However, the vibrating means 500 can be replaced with various vibration generating devices such as pneumatic or hydraulic actuators, provided that the movable base 300 can apply mechanical vibrations.

That is, according to the direct cooling casting apparatus according to the embodiment of the present invention, the crystal grains of the molten metal 2 are first finely ultrasonically vibrated, and grain refinement is secondarily performed by mechanical vibration at the time of solidification The crystal grains can be made very fine and homogeneous and the quality of the castings can be greatly improved.

In the direct cooling casting apparatus according to an embodiment of the present invention, the resin dendrite at the initial stage of solidification is broken by the ultrasonic vibration apparatus 400, Thereby effecting the entire grain refinement effect. However, the transmission of ultrasonic vibration is insignificant in the mushy zone under the molten metal.

Therefore, the present invention is advantageous in that the vibration of the vibration means 500 can be applied from the lower portion of the solid metal 4 to break down the resin intention in the high-concentration coexistence region 3, thereby finely reducing the crystal grain.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is clearly understood that the same is by way of illustration and example only and is not to be taken by way of limitation, Various changes and modifications will be possible.

100: Turn Dish 200: Cooling Mold
210: Cooling water 300:
400: ultrasonic vibration device 500: vibration means

Claims (5)

A tundish which can receive the molten metal and pour it into the cooling mold at a predetermined flow rate;
A cooling mold for solidifying the molten metal poured from the tundish into a solid metal state from a liquid state;
A movable base provided below the cooling mold and solidified in the cooling mold to move up and down to allow the solid metal to be continuously cast;
And an ultrasonic vibrator disposed inside the cooling mold, contacting the molten metal, and performing an operation of stirring the molten metal and refining the grain by outputting an ultrasonic wave by receiving power.
The method according to claim 1,
Wherein the movable base is provided with vibrating means for refining the crystal grains of the solid metal and refining the process structure.
3. The method of claim 2,
Wherein the vibrating means is provided as a motor for vibrating the movable base.
4. The method according to any one of claims 1 to 3,
Wherein the ultrasonic vibration device is formed of a piezoelectric ceramics.
5. The method of claim 4,
Wherein the piezoelectric ceramic is provided in the cooling mold.

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