KR20160039755A - Apparatus for supplying molten metal - Google Patents

Abstract

Provided are an apparatus for supplying molten metal and a method thereof. According to the present invention, the apparatus for supplying molten metal forms a twin roll surface, a mushy zone formed by molten metal, and a sealed space for protective gas to be supplied within the sealed space when supplying molten metal to a twin roll for casting.

Description

[0001] APPARATUS FOR SUPPLYING MOLTEN METAL [0002]

The present invention relates to a molten metal supply apparatus and a method thereof, and more particularly, to a molten metal supply apparatus for supplying a protective gas in a state in which a closed space is formed so that a non-oxidizing atmosphere can be formed during magnesium molten metal casting, will be.

Magnesium is low in density and very low in weight. At the same time, magnesium has a stiffness comparable to that of aluminum. Due to this combination of properties, magnesium is well suited for use in the form of bodywork, particularly in the area of construction of automotive bodies, especially in the form of flat products such as strips or foils.

In order to economically manufacture the magnesium thin plate, the magnesium melt is cast into a preliminary strip of a maximum thickness of 50 mm, and the melt is first introduced into the casting vessel to prevent the melt from coming into contact with oxygen in the air.

The casting vessel is connected with a casting nozzle for feeding the molten metal into the casting gap. The preliminary strip discharged from the casting gap is hot-rolled to a predetermined thickness at the hot rolling initial temperature by the casting heat. This process has the advantage that hot rolling of the preliminary strip can be carried out using the casting heat, so that no reheating is required.

As shown in Figs. 1 and 2, a casting nozzle made of a ceramic material is provided with a pipe nozzle 3 for spraying a protective gas (SF ₆ + N ₂ ) for preventing oxidation of the magnesium molten metal.

The protective gas creates a non-oxidizing atmosphere by spraying a protective gas around the magnesium melt in the mushy state.

The nozzle tip portion 5 of the casting nozzle is required to supply the magnesium melt in a state in which it is as close as possible to the roll lip portion 7 and the approach of the nozzle tip portion 5 is limited by the interference of the roll surface and the pipe nozzle 3 The roll surface is damaged by the pipe nozzle 3 and is dispersed before the protective gas reaches the molten metal passing through the nozzle tip portion 5 and stuck to the roll lip portion 7, that is, the mushy zone There is a problem in that inclusions are generated in the nozzle tip portion 5 and defects are generated in the plate material.

Thus, conventional magnesium strips have a problem in that they have insufficient surface conditions to meet the stringent standards required in most automotive body structures.

In order to solve these problems, there have been various techniques for spraying the protective gas. Hereinafter, some prior arts are introduced.

Korean Unexamined Patent Publication No. 2006-0073345 (Jun. 28, 2006) discloses a " magnesium thin plate casting system using a horizontal twin roll type thin plate casting machine ".

This is achieved by introducing the magnesium melt into the casting gap between the rolls through the casting nozzle and casting it into the preliminary strip, in front of and behind the casting roll in the transport direction, gas spray nozzles connected to the gas supply line system are provided, The gas is sprayed to the upper surface and the lower surface of the preliminary strip toward the casting gap, the magnesium melt flowing into the casting gap and the preliminary strip discharged from the casting gap are prevented from being contacted and oxidized with the surrounding atmosphere and the surface condition is improved.

Korean Patent Publication No. 2010-0023741 (Mar. 4, 2010) discloses a " method and apparatus for producing a magnesium strip ".

The present invention relates to a method and an apparatus for continuously casting a magnesium melt in a magnesium strip in which magnesium or a magnesium alloy is molten between two casting rolls, The flow of the spray. It is a technique to prevent oxidation of the magnesium molten metal by forming a gas curtain in which inert gas surrounds the surface of the casting roll.

However, all of the above-described prior arts relate to a technique for forming a non-oxidizing atmosphere by spraying a protective gas to prevent the oxidation of the molten metal when the magnesium melt is supplied between the twin rolls. However, as described above, There is a limit to creating an atmosphere.

The present inventors have recognized the problems of these prior arts and have arrived at the present invention which solves the problems related to interference of the pipe nozzle with the roll surface, damage to the roll surface, and formation of an anoxic atmosphere in the mush zone.

It should be understood that the foregoing description of the background art is merely for the purpose of promoting an understanding of the background of the present invention and is not to be construed as adhering to the prior art already known to those skilled in the art.

Korean Patent Publication No. 2006-0073345 (2006.06.28) Korean Patent Publication No. 2010-0023741 (Mar. 4, 2010)

In order to solve such a conventional problem, the present invention provides a method of forming a completely non-oxidizing atmosphere by spraying a protective gas in a state in which a closed space (sealing space) is formed between a twin roll, a mush zone, And to provide a molten metal supplying apparatus and method therefor.

In order to achieve the above object, the present invention provides a molten metal supplying apparatus comprising a mushroom zone formed by a twin roll surface and a molten metal so that a protective gas can be supplied in a sealed space when molten metal is supplied to a twin roll for casting, Thereby forming a space.

A gas injection part for injecting a protective gas; A nozzle tip coupled to the gas ejection portion to supply the molten metal between the twin rolls; And a curtain portion selectively contacting the surface of the twin roll.

Wherein the twin roll includes an upper roll and a lower roll, and the gas injection portion is formed with a spray hole coupled to a tip end of the nozzle housing and configured to spray a protective gas to the upper roll and the lower roll surface The curtain portion including an upper curtain in selective contact with the upper roll and a lower curtain in selective contact with the lower roll.

The upper curtain is inclined toward the upper roll, and the lower curtain is inclined toward the lower roll.

Wherein the pipe nozzle includes an upper pipe nozzle having an upper injection hole for injecting a protective gas into the upper roll and a lower pipe nozzle having a lower injection hole for injecting a protective gas into the lower roll, Wherein the through hole is formed to be inclined upward toward the upper roll, and the lower injection hole is formed to be inclined downward toward the lower roll.

Wherein the upper curtain includes a first upper curtain and a second upper curtain having a steeper angle than the first upper curtain, wherein the lower curtain has a first lower curtain and an inclined angle And a second lower curtain formed more rapidly.

One side of the first upper curtain and the second upper curtain are united and branched from each other toward the other side, and one side of the second lower curtain and the second lower curtain are unified and branched from each other toward the other side .

In order to accomplish the above object, the present invention provides a method for supplying molten metal to a twin roll for casting, comprising the steps of: forming a mushroom zone formed by a twin roll surface and a molten metal, And a protective gas is introduced.

The present invention has the advantage of preventing the dispersion of the protective gas and blocking the outside air by preventing the oxidation of the molten metal present in the machine zone during casting and improving the shape and quality of the plate material.

Further, there is an advantage that the damage of the roll surface caused by interference of the pipe nozzle with the roll surface can be prevented.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 shows a conventional roll lid and a melt flow mechanism in a mush zone,
FIG. 2 is a schematic view showing a state where a protective gas to which a conventional pipe nozzle is applied,
3 is a side view of an embodiment of the present invention,
4 is a front view of an embodiment of the present invention;
5 is a view showing another embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a molten metal supplying apparatus and method according to a preferred embodiment of the present invention will be described with reference to the accompanying drawings.

The molten metal supplying method of the present invention is characterized in that a shielding space is formed between a mushroom zone formed by a twin roll surface and a molten metal when a molten metal is supplied to a twin roll for casting and then a protective gas for preventing oxidation of the molten metal is charged .

Hereinafter, an apparatus capable of forming a completely anoxic atmosphere by applying this method will be described.

It is a very important factor to prevent the oxidation of the molten metal during the casting work in terms of securing the quality of the plate material. Particularly, it has a low weight and density and is excellent in rigidity, and therefore, a technique for preventing oxidation in a magnesium plate used in an automobile body structure is a very important factor.

The molten metal supply device of the present invention is for preventing the molten metal from being oxidized in the casting process and is formed by twin roll surface and molten metal so that the protective gas can be supplied in the sealed space when the molten metal is supplied to the twin roll for casting And forms a closed space with the mushroom zone.

3 and 4, the molten metal supplying apparatus of the present invention includes a gas spraying section 10, a nozzle tip 20, and a curtain section 30. As shown in Fig.

When the magnesium melt is cast while passing between the upper roll (UR) and the lower roll (DR) of the twin roll (R), there is a region where the melt reaches the mush state.

Although there has been an effort to provide a non-oxidizing atmosphere at the time of casting using the conventional protective gas, there has been a limitation in forming a completely non-oxidizing atmosphere due to interference between the casting nozzle and the roll. In the present invention, ) Was introduced to create a completely oxidizing atmosphere.

In the gas injector 10, a protective gas is injected, and a mixed gas of SF6 + N2 is used as a protective gas.

A nozzle tip 20 is coupled to the front end of the gas injection unit 10 and the nozzle tip 20 is formed of a ceramic material and functions to supply the molten metal to the twin roll R. [

The curtain portion 30 is selectively brought into contact with the surface of the twin roll R to form a closed space between the surface of the twin roll R and the mush zone Z so that the protective gas flows out or is dispersed , And prevents the molten metal present in the mushroom zone (Z) from being oxidized.

The present invention further comprises a nozzle housing (40), wherein the twin roll (R) comprises an upper roll (UR) and a lower roll (DR).

The gas injection unit 10 is connected to the tip end of the nozzle housing 40 and includes a pipe nozzle 12 having a spray hole 14 for spraying a protective gas toward the upper roll UR and the lower roll DR The curtain portion 30 includes an upper curtain 32 selectively in contact with the upper roll UR and a lower curtain 34 selectively in contact with the lower roll DR.

According to the present invention, since the protective gas is supplied in a state where the upper curtain 32 and the lower curtain 34 are in contact with the upper roll UR and the lower roll DR, respectively, And the space formed between the molten metal in the mash state and the upper curtain 32, the lower roll DR and the molten metal in the mash state and the lower curtain 34 form a completely anoxic atmosphere.

Further, since the upper curtain 32 and the lower curtain 34 contact the upper roll UR and the lower roll DR, respectively, there is no possibility that the nozzle housing 40 or the like comes into contact with the roll surface, There is an advantage that it can be prevented.

The pipe nozzle 12 includes an upper pipe nozzle 12a formed with an upper injection hole 14a for injecting a protective gas into the upper roll UR and a lower pipe nozzle 12b for injecting a protective gas into the lower roll DR. And a lower pipe nozzle 12b in which a hole 14b is formed.

It is preferable that the upper spray hole 14a is formed to be inclined upward toward the upper roll UR and the lower spray hole 14b is formed to be inclined downward with respect to the lower roll DR, So that the oxidation preventing effect can be maximized.

The upper curtain 32 is inclined toward the upper roll UR so that the lower curtain 34 can be aligned with the forming direction of the upper spray hole 14a and the lower spray hole 14b, It is preferable that the protective gas to be injected is directly sprayed onto the roll surface without interference between the upper curtain 32 and the lower curtain 34. [

5, the upper curtain 32 of the melt supply device of the present invention preferably includes a first upper curtain 32a and a second upper curtain 32b, and the lower curtain 34 May include a first lower curtain 34a and a second lower curtain 34b.

It is possible to maximize the sealing effect by making the upper curtain 32 and the lower curtain 34 each have a double structure so that the inclination of the second upper curtain 32b is formed larger than the inclination of the first upper curtain 32a The inclination of the second lower curtain 34b is made larger than the inclination of the first lower curtain 34a so that it is possible to further facilitate the contact with the upper roll UR and the lower roll DR.

One side of the first upper curtain 32a and one side of the second upper curtain 32b are integrally formed and branched from each other toward the other side and one side of the second lower curtain 34b and the second lower curtain 34b And the pressure difference between the first upper curtain 32a and the first lower curtain 34a can be improved by forming the first upper curtain 32a and the second lower curtain 34b so that they are branched from each other.

Hereinafter, with reference to FIG. 4, an operation process of the molten metal supplying apparatus of the present invention will be briefly described.

When the melt is supplied between the twin rolls (R), the nozzle tip (20) is located as close as possible to the horizontal formed space between the upper roll (UR) and the lower roll (DR).

At this time, the first upper curtain 32a and the second upper curtain 32b, the first lower curtain 34a and the second lower curtain 34b come into contact with the upper roll UR and the lower roll DR, respectively And an airtight space is formed between the upper surface of the upper roll (UR) and the inner surface of the first upper curtain (32a), and a closed space is formed between the inner surface of the lower roll (DR) surface and the inner surface of the first lower curtain A protective gas sprayed from the gas spraying unit 10 is not leaked to the outside but is present in a closed space, so that a completely non-oxidizing atmosphere is formed in the mash zone Z.

While the present invention has been particularly shown and described with reference to specific embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the following claims It will be apparent to those of ordinary skill in the art.

10: gas injection part 12: pipe nozzle
12a: upper pipe nozzle 12b: lower pipe nozzle
14: Spout hole 14a: Top spout hole
14b: lower spray hole 20: nozzle tip
30: curtain portion 32: upper curtain
32a: first upper curtain 32b: second upper curtain
34: lower curtain 34a: first lower curtain
34b: second lower curtain 40: nozzle housing
R: Twin roll UR: Upper roll
DR: Lower roll Z: Mush zone

Claims (8)

Characterized in that it forms a closed space with the mullion zone formed by the twin roll surface and the molten metal so that the protective gas can be supplied in the sealed space when supplying the molten metal to the twin roll for casting.
The method according to claim 1,
A gas injection part for injecting a protective gas;
A nozzle tip coupled to the gas ejection portion to supply the molten metal between the twin rolls; And
And a curtain portion selectively contacting the surface of the twin roll.
The method of claim 2,
Further comprising a nozzle housing,
The twin roll includes an upper roll and a lower roll,
Wherein the gas injection unit includes a pipe nozzle coupled to a front end of the nozzle housing and having a spray hole for spraying a protective gas to the upper roll and the lower roll surface,
Wherein the curtain portion comprises an upper curtain and a lower curtain in selective contact with the upper roll and a lower curtain in selective contact with the lower roll.
The method of claim 3,
Wherein the upper curtain is inclined toward the upper roll, and the lower curtain is inclined toward the lower roll.
The method of claim 4,
Wherein the pipe nozzle includes an upper pipe nozzle having an upper injection hole for injecting a protective gas into the upper roll and a lower pipe nozzle having a lower injection hole for injecting a protective gas into the lower roll,
Wherein the upper injection hole is formed to be inclined upward toward the upper roll and the lower injection hole is formed to be inclined downward with respect to the lower roll.
The method of claim 5,
Wherein the upper curtain includes a first upper curtain and a second upper curtain with a steeper angle than the first upper curtain,
Wherein the lower curtain comprises a first lower curtain and a second lower curtain with a steeper angle of inclination than the second lower curtain.
The method of claim 6,
Wherein one side of the first upper curtain and the second upper curtain are united and branched from each other toward the other side,
Wherein one side of the second lower curtain and the second lower curtain are integrally formed and branched from each other toward the other side.
Wherein a molten metal is formed on the twin roll surface and the molten metal when the molten metal is supplied to the twin roll for casting, and then a protective gas is introduced to prevent oxidation of the molten metal after forming a sealed space.

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