JP3856935B2 - Equipment for degassing and cleaning molten metal - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an apparatus for degassing and purifying a molten metal that removes dissolved gas such as hydrogen gas and oxygen gas from a molten metal of a non-ferrous metal such as aluminum or copper or an alloy mainly composed of these metals.
[0002]
[Prior art]
As one type of molten metal degassing cleaning device, as shown in FIG. 2, a tubular rotating body 2 provided with a stirring blade 1 at the lower end is immersed in the molten metal 4 in the melting tank 3 and melted by the stirring blade 1. While stirring the metal 4, a fluxing gas such as an inert gas is blown into the molten metal 4 from the gas passage 5 that opens to the lower end surface of the tubular rotating body 2, and dissolved gases such as hydrogen gas and oxygen gas in the molten metal 4. And the apparatus which removes the nonmetallic inclusion 6 is provided for practical use.
[0003]
[Problems to be solved by the invention]
In the conventional degassing and cleaning apparatus described above, when the rotational speed of the tubular rotating body 2 is increased to enhance the stirring effect, a vortex is generated around the rotating body 2 and floats on the molten metal surface 7 of the molten metal 4. Since the non-metallic inclusions 6 are entrained in the vortex, they penetrate into the inside of the molten metal 4 along the tubular rotating body 2 and this causes hard spot defects in the cast product.
In view of such problems, an object of the present invention is to provide an apparatus for degassing and purifying a molten metal that has an excellent stirring effect and prevents the inclusion of nonmetallic inclusions in the molten metal.
[0004]
[Means for Solving the Problems]
According to the first aspect of the present invention, a tubular rotating body having a stirring blade at the lower end is immersed in the molten metal, and fluxing gas is supplied from the tubular rotating body into the molten metal while stirring the molten metal with the stirring blade. An apparatus for degassing and purifying a molten metal that blows in and removes dissolved gas in the molten metal, and is provided with an annular protrusion protruding in the radial direction of the rotating body on the outer periphery of the intermediate portion immersed in the molten metal of the tubular rotating body The non-metallic inclusions floating on the surface of the molten metal during the rotation of the tubular rotating body are blocked by the annular protrusion and are not caught in the molten metal .
Preferably, the annular projection has a shape in which two frustoconical bottom surfaces are joined.
[0005]
[Operation and effect of the invention]
According to the present invention, even if a vortex is generated with the rotation of the tubular rotating body, the non-metallic inclusions floating on the molten metal surface are blocked by the annular protrusion provided at the intermediate portion of the tubular rotating body. Therefore, the hard spot defect of the cast product due to the non-metallic inclusions can be prevented.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be described below with reference to the drawings. FIG. 1 shows a degassing / cleaning apparatus 10 for molten metal according to an embodiment of the present invention. The degassing cleaning device 10 includes a tubular rotating body 13 that is immersed in the molten metal 12 in the melting tank 11.
A stirring blade 14 is fixed to the lower end portion of the tubular rotating body 13. A gas passage 15 is formed at the center of the tubular rotator 13, and one end is open to the lower end surface of the annular rotator 13. The gas passage 15 is connected to a gas cylinder (not shown) filled with a fluxing gas such as an inert gas through the inside of a support portion 16 that suspends the tubular rotator 13 in a rotatable manner.
An annular protrusion 17 that projects in the radial direction of the rotating body 13 is integrally provided on the outer periphery of the intermediate portion of the tubular rotating body 13. The annular protrusion 17 has a shape in which two frustoconical bottom surfaces are joined, and is disposed so as to be located at a depth of about 1/3 of the immersion length of the tubular rotating body 13 from the molten metal surface 18 of the molten metal 12. Yes. The outer dimension A of the annular protrusion 17 is set to 0.5 to 1 times the outer dimension B of the stirring blade 14.
[0007]
The structure of the molten metal degassing and purifying apparatus 10 according to the present embodiment is as described above. While the tubular rotating body 13 is immersed in the molten metal 12 and the stirring blade 14 is rotated, the flux is removed from the gas passage 15. A gas is blown into the molten metal 12 to remove dissolved gases such as hydrogen gas and oxygen gas and non-metallic inclusions in the molten metal 12.
Therefore, according to the degassing cleaning device 10 according to the present embodiment, even if a vortex is generated around the rotating body 13 as the tubular rotating body 13 rotates, it floats on the molten metal 12 surface 18. Since the non-metallic inclusions 19 are blocked by the annular protrusions 17 provided in the intermediate portion of the tubular rotating body 13 and do not get deeper into the molten metal 12, the non-metallic inclusions 19 Hard spot defects can be prevented.
Further, if the outer dimension A of the annular protrusion 17 is too small, an effect sufficient to prevent the non-metallic inclusions 19 from being caught by eddy currents cannot be obtained. Since the body 13 is heavy and bulky, it is very inconvenient to handle and easily damaged, but the outer dimension A of the annular protrusion 17 is 0.5 to 1 times the outer dimension B of the stirring blade. The effect of preventing the entrainment of the period is obtained, the handling is easy, and the damage is difficult.
[Brief description of the drawings]
FIG. 1 is a partially cutaway front view showing an apparatus for degassing and purifying molten metal according to an embodiment of the present invention.
FIG. 2 is a partially broken front view showing a conventional degassing cleaning apparatus.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Degassing purification apparatus of molten metal, 11 ... Melting tank, 12 ... Molten metal, 13 ... Tubular rotary body, 14 ... Stirring blade, 15 ... Gas passage, 16 ... Support part, 17 ... Ring-shaped protrusion, 18 ... Hot water Surface, 19 ... non-metallic inclusions.

Claims (2)

A tubular rotating body having a stirring blade at the lower end is immersed in the molten metal, and while the molten metal is stirred by the stirring blade, a fluxing gas is blown into the molten metal from the tubular rotating body to dissolve the dissolved gas in the molten metal. An apparatus for degassing and purifying a molten metal to be removed, wherein an annular protrusion protruding in a radial direction of the rotating body is provided on an outer periphery of an intermediate portion immersed in the molten metal of the tubular rotating body, and the molten metal is rotated when the tubular rotating body rotates. An apparatus for degassing and purifying molten metal, wherein non-metallic inclusions floating on the surface of the molten metal are blocked by the annular protrusions and are not caught inside the molten metal. The apparatus for degassing and purifying molten metal according to claim 1, wherein the annular protrusion has a shape in which two bottoms of a truncated cone shape are joined .

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