KR101036206B1 - Stirring for Metal Melt - Google Patents

Abstract

The present invention provides a stirring metal for molten metal capable of miniaturizing and homogenizing bubbles of blown gas. The stirring liquid 1 for molten metal of this invention provides the stirring blade 2 which provided the passage groove part 22 of radial blowing gas in the bottom face part 2a at the front-end | tip of the cylindrical shaft 3, The projection bottom area ratio of the passage groove portion 22 to the projection bottom area of the stirring blade 2 portion is set to be 0.20 to 0.60. The stirring blade 2 can be formed in disk shape, and ratio of the length of the said channel | channel groove part 22 with respect to the radius can be 0.5-0.9.

Description

Agitator for molten metal {DEVICE FOR STIRRING MOLTEN METAL}

TECHNICAL FIELD The present invention relates to a metal molten metal stirring body used to perform degas treatment of molten metal such as aluminum.

Degassing treatment, such as aluminum or an aluminum alloy, is performed by stirring a metal molten metal with a stirring body for metal molten metals, for example, blowing blowing gas, such as argon and nitrogen, into metal molten metals, such as aluminum. By this treatment, harmful gases such as hydrogen and micro inclusions, such as hydrogen fused in the molten metal, can be introduced into the blown gas and removed.

In order to improve the effect of the degassing treatment, it is necessary to increase the stirring efficiency of the molten metal and to blow the blown gas blown into the molten metal into a fine and uniform size to diffuse into every corner of the molten metal.

Patent Documents 1 to 5 below disclose that a metal molten metal provided with a radial groove on the bottom of the stirring blade is disclosed, and that the inert gas passing through the radial groove is subdivided by the shearing action by the rotation of the stirring blade. .

The following patent documents 6 and 7 disclose the stirring object for molten metal which provided the projection part radially on the bottom face of the stirring blade, and it describes that the bubble is cut | disconnected finely by a projection part.

Patent Literature 8 below discloses a metal molten metal having a plurality of grooves having a triangular cross-sectional shape formed on the bottom of a stirring blade, which forms a vortex by the grooves, stirs the bubbles, and subdivides the bubbles. have.

JP-A 7-23098 (claims 1, 2, etc.) Japanese Unexamined Patent Publication No. 3-91161 (second degree, etc.) JP-A 7-53804 (the second degree, etc.) Japanese thread 2504800 publication (the second degree) Japanese Patent Laid-Open No. 7-55365 (Fig. 2, etc.) JP 2001-59122 A (claim 1, FIG. 1, etc.) Japanese Patent Laid-Open No. 2003-130557 (Fig. 2, etc.) Japanese Patent Laid-Open No. 2003-328046 (Claim 1, Fig. 2, etc.)

As mentioned above, the bubble of blown gas needs to be refine | miniaturized and uniformized in the molten metal.

In the stirring object for molten metal of patent documents 1-5, the bubble which flows through a radial groove leaks before reaching the outer peripheral part, and the bubble of large diameter may disperse | distribute in a molten metal.

Moreover, in the stirring object for metal melts of patent documents 6 and 7 cut | disconnects a bubble finely with a projection part, even if a bubble becomes fine, the magnitude | size is nonuniform, and also the stirring object for metal melts described in said patent document 8 is vortex By making it possible to refine the bubble, it was difficult to uniformly adjust the size.

These result in deterioration of degassing performance, and as a result, bubbles remaining in the metal product, thereby producing defective products.

Then, the objective of this invention is providing the stirring object for molten metal which can refine | miniaturize and uniformize the bubble of blown gas.

In the molten metal for metal molten metal of this invention, in the molten metal for metal molten metal which provided the stirring blade which provided the radial passage groove part through which blowing gas flows in the bottom part in the front-end | shaft of a shaft, projection of a stirring blade part is carried out. The ratio of the projected floor area of the passage groove portion to the floor area is set to 0.20 to 0.60.

The stirring object for molten metal of this invention can refine | miniaturize and uniformize the bubble of blown gas by making ratio of the projected area of a stirring blade and the projected area of a channel | path groove part into a predetermined range.

BRIEF DESCRIPTION OF THE DRAWINGS The perspective view of the metal molten metal stirring body of one Embodiment of this invention.
FIG. 2 is a bottom view of the stirring body shown in FIG. 1. FIG.
3 is a cross-sectional view of the stirring blade portion of the stirring body shown in FIG. 1.
Fig. 4 is a partially enlarged perspective view showing the bottom side of the stirring body shown in Fig. 1.
FIG. 5 is an oblique view of the projection bottom area of the stirring blade portion of the stirring body shown in FIG. 1. FIG.
FIG. 6 is an oblique view of the projection bottom area of the passage groove portion of the stirring body shown in FIG. 1. FIG.
The perspective view of the stirring object for metal molten metal of another embodiment of this invention.
8 is a bottom view of the stirring body shown in FIG. 7.
9 is a side view of the stirring body shown in FIG. 7.
FIG. 10 is a side view showing a modification of the groove portion in the stirring body shown in FIG. 7. FIG.
FIG. 11 is a side view showing another modification of the groove portion in the stirring body shown in FIG. 7. FIG.
12 is a partially enlarged bottom view of the stirring body shown in FIG. 7.
It is sectional drawing of the stirring body shown in FIG.
14 is a partially enlarged perspective view of the stirring body shown in FIG. 7.
FIG. 15 is an oblique view of the projection bottom area of the passage groove portion of the stirring body illustrated in FIG. 7. FIG.
The figure which shows the shape of the stirring object for metal melts of Examples 15-23 and Comparative Examples 10-13, (a) is a bottom view, (b) is XX sectional drawing.

EMBODIMENT OF THE INVENTION Hereinafter, the stirring object for molten metal of one Embodiment of this invention is demonstrated. In addition, the scope of the present invention is not limited to this embodiment.

As shown in FIG. 1 etc., the stirring object 1 for metal molten metal of one Embodiment of this invention fixes the stirring blade 2 and the shaft 3 integrally by fastening or adhering.

The stirring blade 2 and the shaft 3 can be formed from silicon nitride ceramics, cyanone ceramics, silicon carbide ceramics, carbon ceramics, carbon, and the like, and more specifically, the silicon nitride powder is sintered with a sintering aid. Silicon carbide-based ceramics composed of silicon nitride-based ceramics, siaron-based ceramics, silicon carbide powder sintered with silicon carbide powder, or silicon nitride-bonded silicon carbide sintered body containing 70% by weight or more of silicon carbide, carbon, silicon carbide, carbide Boron etc. can be mixed and it can be formed from carbon ceramics etc. made into a sintered compact.

As shown in FIG. 2, FIG. 3, etc., the stirring blade 2 is formed in disk shape, and enables the front-end | tip of the shaft 3 to adhere to the circular hole provided in the center, and a bottom face part In 2a, the circular concave storage part 21 which collects blowing gas is formed, and the radial passage groove part 22 through which blowing gas passes is formed, and the outer peripheral part 2b The notches 23 are formed at appropriate intervals.

Although the stirring blade 2 is not specifically limited, The diameter is 120 mm-300 mm, Preferably it is 170 mm-230 mm, The thickness is 10 mm-35 mm, Preferably it is 20 mm-30 It is formed in mm.

As shown in FIG. 1 or FIG. 2, the storage portion 21 is a concave space in a circular shape surrounded by the bottom face 3a of the shaft 3 and the inner circumferential portion 2c of the stirring blade 2. And the blowing gas blown out from the shaft 3 can be collected.

Although the storage part 21 is not specifically limited, The diameter is 40 mm-80 mm, Preferably it is 50 mm-70 mm, The depth is 6 mm-15 mm, Preferably 8 mm-12 It is formed in mm.

It is preferable to incline and form the inner peripheral part 2c so that it may become narrow vertically or downward, and it becomes difficult for blowing gas to escape from the storage part 21 by doing in this way.

As shown in FIGS. 1-4 etc., the passage groove part 22 is formed in multiple numbers radially in the bottom face part 2a of the stirring blade 2, and the inner peripheral side opening edge part 22a is provided in the inner peripheral part 2c. Blown gas collected in the storage portion 21 by forming the outer circumferential side opening end portion 22b at the outer circumferential portion 2b of the stirring blade 2 and continuing the storage portion 21 and the outer circumferential portion 2b. Bubble can be sent out to the outer peripheral part 2b side of the stirring blade 2.

Although the shape of the passage groove part 22 is not specifically limited, It can form in cross-sectional square shape, cross-sectional arc shape, cross-sectional triangular shape, etc.

The ratio of the projection bottom area (the diagonal portion in FIG. 6) of the passage groove portion 22 to the projection bottom area (the diagonal portion in FIG. 5) of the stirring blade 2 portion is 0.20 to 0.60, preferably 0.30 to 0.50. The ratio of the length of the passage groove portion 22 to the radius of the stirring blade 2 may be 0.5 to 0.9, preferably 0.6 to 0.8.

In addition, the projection bottom area of the stirring blade 2 part is the projection bottom area of the part which combined the bottom part 2a of the stirring blade 2, and the bottom face 3a of the shaft 3 together.

The width of the passage groove portion 22 can be formed in a taper shape such that the width thereof becomes gradually wider or narrower toward the outer circumferential portion 2b. In this case, the width of the inner circumferential side opening end 22a The ratio of the width of the outer circumferential side opening end portion 22b may be 0.5 to 6.0, preferably 0.8 to 2.0.

The ratio of the depth of the passage groove part 22 with respect to the width | variety of the outer peripheral side opening edge part 22b is 0.3-3.0, Preferably it is 0.5-1.5.

The notch part 23 is arrange | positioned between each groove part 22 of the outer peripheral part 2b of the stirring blade 2, and cut out and formed in square shape.

The notch 23 is not particularly limited, but the width is 6 mm to 10 mm, preferably 7 mm to 9 mm, and the depth 6 mm to 14 mm, preferably 8 mm to 12 mm. It can form in mm.

As shown in FIG. 1, FIG. 2, etc., the shaft 3 has a cylindrical shape with a bottom face 3a, has an inside through a passage through which blowing gas flows, and roughly the bottom face 3a. At the center, a circular gas blowing port 31 for blowing blown gas is formed.

The agitated body 1 for molten metal thus formed can disperse bubbles having finer size and uniform size into the molten metal, thereby increasing the efficiency of degassing treatment.

In addition, when the material of a stirring body is made into the said ceramics, in order to make it excellent in thermal shock resistance and abrasion resistance, it is preferable to set it as the form shown below.

7-15, the stirring metal 4 for metal molten metal which consists of ceramics of another form is shown.

As shown in FIGS. 7-9, the stirring blade 5 is formed in the shape of an umbrella in which the center part was raised, and the front end of the shaft part 6 can be fixed to the circular hole provided in the substantially center. . The notch part 51 is formed in the outer peripheral part 5a of the stirring blade 5, and the taper part 52 and the passage groove part 53 are formed in the bottom face part 5b.

The thickness (dimension t _{i in} FIG. 13) on the inner peripheral portion 5c side of the stirring blade 5 is 4.0 to 9.0%, particularly 5.0 to 8.0% of the diameter, from the viewpoint of achieving both agitation efficiency and thermal shock resistance. preferably formed at a rate, and further, with respect to the outer peripheral portion (5a), the thickness (dimension t ₀ in Fig. 9) of the side, it is preferable to form double 0.9 to 2.0 times, especially 1.1 to 1.6.

Specifically, the diameter of the stirring blade 5 is 120 mm-300 mm, especially 170 mm-230 mm, The thickness of the inner peripheral part 5c is 7 mm-21 mm, Especially 9 mm-18 mm It is preferable that the thickness of the outer peripheral portion 5a be 6 mm to 16 mm, particularly 8 mm to 12 mm.

In addition, the thickness mentioned in this invention excludes the part which provided the channel | path groove part 53. As shown in FIG.

As shown in FIG. 8, FIG. 12, etc., the notch part 51 is cut out and formed in the square shape at the suitable space | interval 5a of the stirring blade 5, and the inside (shaft part 6 side) of the notch part 51 is formed. Both corner portions 51a and 51a are formed in a rounded corner shape.

As shown in FIG. 8, FIG. 13, etc., the taper part 52 is formed in the vicinity of the center of the bottom face part 5b, and gradually spreads outward from the front end side of the shaft part 6 downward in a cross section. It is formed in an inclined shape.

As shown in FIG. 8, FIG. 9, FIG. 14, etc., the channel | path groove part 53 is a groove of a semicircular cross section, and each notch part 51 is directed toward the outer side from the taper part 52 to the bottom part 5b. It is formed in multiple numbers radially so that it may pass to the outer peripheral part 5a past.

At this time, the projection bottom area of the passage groove part 53 becomes a part shown by the oblique part of FIG.

On the other hand, although the channel | channel groove part 53 is formed in cross-section semi-circle shape, it is not limited to this, The channel | channel groove part 53a of cross-sectional square shape shown in FIG. 10, and the U-shaped cross-sectional path shown in FIG. It may be formed by the groove portion 53b or the like.

As shown in FIG. 13, the shaft part 6 is made into the cylindrical shape which has the bottom part 6a at the front-end | tip, provides a circular hole in the substantially center of the bottom part 6a, and makes this hole a gas ejection opening ( 61, the blowing gas passes through the inside and is injected from the gas blowing port (61). The inner side of the bottom part 6a of the shaft part 6 is formed as the curved surface 62 recessed in the hemispherical shape so that it may become narrow toward the gas ejection opening 61.

Since the stirring blade 4 for metal molten metal made the stirring blade 5 into an umbrella shape, and limited the thickness of the inner peripheral part 5c to the predetermined range, it is excellent in thermal shock resistance and breaks even if it uses repeatedly. It becomes difficult, and since it consists of ceramics, it becomes excellent also in abrasion resistance.

Example

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated more concretely based on an Example. However, the scope of the present invention is not limited to this embodiment.

Test 1

As Examples 1-14 and Comparative Examples 1-9, the stirring object for metal molten metal of the shape and material as shown in Table 1 was formed, and degassing performance was measured using each stirring body.

<Degassing performance>

The stirring body was immersed in the aluminum molten metal of hot water 730 degreeC and 600 kg, and the degassing process was carried out by operating the stirring body at rotation speed of 600 rpm and 30 L / min of Ar gas as blowing gas, and degassing treatment. The molten metal was put into the mold and the cross-sectional state of the obtained casting was visually observed. "(Circle)" and the state (there is no problem in practical use) where there is no pore was evaluated as "(circle)", and the state with the hole (the degree which has a problem in practical use) as "(triangle | delta)".

TABLE 1

(result)

Examples 1 to 14 had no pores or almost no pores, and brought good results. In Comparative Examples 1 to 9, pores were generated in all, resulting in poor results.

From these results, as shown to Examples 1-14, if the projection bottom area of the passage groove part with respect to the projection bottom area of the stirring blade part is a range of 0.25-0.55, it is evaluation of "(circle)" or "(◎)", and it is a favorable demounting. It becomes the stirring body which has gas performance.

In addition, as shown in Comparative Examples 1-9, when the projection area of the passage groove part with respect to the projection bottom area of the stirring blade part is 0.17 or less or 0.61 or more, it is evaluation of "(triangle | delta)" and degassing is not performed sufficiently. This was confirmed.

From these, it is thought that it becomes a stirring body which has favorable degassing performance in the range of the projection bottom area of the passage groove part with respect to the projection bottom area of the stirring blade part in 0.20-0.60.

(Test 2)

As the stirring bodies of Examples 15-23 and Comparative Examples 10-13, the stirring bodies of the shape shown in FIG. 16 were formed. The thickness, diameter, etc. of the inner peripheral part and the outer peripheral part of the stirring blade were formed as shown in Table 2, and the shape of the taper part, the notch part, the passage groove part was formed as follows.

Tapered part

Length: 12% against diameter

Height: 8 mm

Notch

Width: 10% against diameter

Depth: 10% against diameter

Embossed R: 4 mm

Pathway groove

Width: 5% against diameter

Depth: 50% of the thickness of the outer circumference

Projection bottom area of the passage groove part relative to the projection bottom area of the stirring blade part: 0.34

The following thermal shock resistance test was done using the stirring body of Examples 15-23 and Comparative Examples 10-13. The results are shown in Table 2 below.

TABLE 2

(Thermal shock resistance test)

Examples 15-23 and Comparative Examples 10-13 were immersed in the molten aluminum adjusted to the constant temperature from normal temperature (about 20 degreeC), without preheating, and hold | maintained for 5 minutes. Then, it removed from the molten aluminum, cooled in air | atmosphere, visually confirmed the presence or absence of a crack, and judged with the following evaluation criteria.

(Double-circle): There is no crack even if it cools after immersing in the aluminum molten metal of 800 degreeC.

(Circle): Although it does not crack even if it cools after immersing in 750 degreeC aluminum molten metal, it is cracked at 800 degreeC.

(Triangle | delta): Although it does not crack even if it cools after immersing in the aluminum molten metal of 700 degreeC, when it was 750 degreeC, it is broken.

X: After immersion in the aluminum molten metal of 700 degreeC, it cools and is cracked.

(result)

In Examples 15-23, the crack did not generate | occur | produce above 750 degreeC in the thermal shock resistance test. In Comparative Examples 10-13, the crack generate | occur | produced all at 750 degreeC in the thermal shock resistance test, and the comparative example 13 had the crack even if it was 700 degreeC.

Thus, from the results of Comparative Examples 10 and 11, the ratio of the inner circumferential thickness and the outer circumferential thickness (inner circumferential thickness / outer circumferential thickness) is inferior to thermal shock resistance if it is 0.7 or 2.2.

In addition, from the results of Comparative Examples 12 and 13, if the ratio of the thickness of the inner circumference to the diameter of 3.0% or 10% decreases the thermal shock resistance, it is considered that the thickness of the inner circumference is about 4.0 to 9.0% with respect to the diameter. .

DESCRIPTION OF SYMBOLS 1 Stirring body for metal molten metal 2 Stirring blades
3: shaft 21: reservoir
22: passage groove 23: notch

Claims (11)

In the stirring body for molten metal which provided the stirring blade which provided the channel groove part of the radial blowing gas in the bottom part in the front-end | tip of a shaft,
The stirring body for metal molten metal which made the ratio of the projection bottom area of the passage groove part with respect to the projection bottom area of the stirring blade part set to 0.20-0.60. The method of claim 1,
The stirring blade is formed in disk shape, and the stirring body for molten metal which made ratio of the length of the said channel | path groove part with respect to the radius 0.5-0.9. The method according to claim 1 or 2,
The said passage groove part is the stirring object for molten metal which made ratio of the width | variety of the outer peripheral side opening edge part with respect to the width | variety of the inner peripheral side opening edge part 0.5-6.0. The method according to claim 1 or 2,
The said channel | channel groove part is the stirring object for molten metal which made ratio of the depth with respect to the width | variety of the outer edge side opening edge part 0.3-3.0. The method according to claim 1 or 2,
A metal molten stirring body provided with a square notch at appropriate intervals on an outer peripheral portion of a stirring blade. The method according to claim 1 or 2,
The stirring body for metal molten metal which made the material of the stirring blade into at least 1 sort (s) of silicon nitride type ceramics, cyanone type ceramics, silicon carbide type ceramics, carbon ceramics, and carbon. The method of claim 1,
The stirring blade was made into an umbrella shape, the thickness of the inner peripheral part of the stirring blade was 4.0 to 9.0% with respect to the diameter, and the stirring body for molten metal which made 0.9 to 2.0 times the thickness of the outer peripheral part. The method of claim 7, wherein
The stirring body for molten metal which provided the taper part which gradually spreads downward from the front end side of a shaft part in the bottom face part of a stirring blade. The method according to claim 7 or 8,
A rectangular stirring notch portion is provided at appropriate intervals in an outer peripheral portion of the stirring blade, and both stirring portions inside the notch portion are formed in an arc shape. The method according to claim 7 or 8,
The stirring object for molten metal which formed the channel | channel groove part in semi-circle of a cross section, U shape, or square shape. The method according to claim 7 or 8,
The metal molten metal body which provided the gas injection port in the substantially center of the bottom part of the shaft part, and made the inside of the said bottom part concave to a hemispherical shape.

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