JPH0584545A - Method and device for casting aluminum composite material - Google Patents

Abstract

PURPOSE:To provide a casting device which can surely prevent mixture of the air into a casting and disturbance of the flow velocity of a molten metal even if an daaitive is stirred and mixed into a molten aluminum and poured into a mold and can obtain the sound casting product of aluminum composite without any defect of blow hole, etc., and particularly, is the most suitable for casting the casting product of the aluminum composite stirring and mixing SiC particles and is effective to obtain a light alloy brake disk rotor, etc., for car, etc., excellent in wear resistance and high rigidity. CONSTITUTION:On the halfway of a runner 14 pouring the molten metal A of the aluminum composite mixing the additive in the aluminum into a casting forming part 15 in the mold 11 from a sprue 12, a bubble trap 17 for removing air in the molten metal is prvided. Further, at the tip part side of the runner 14, a choke 18 for controlling the flow velocity of the molten metal A by changing the cross sectional air is provided and also a filter 20 for removing impurities in the molten metal A is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a casting method and apparatus for producing a light alloy casting product of an aluminum composite material which is mainly used as a brake disc rotor for automobiles and the like.

[0002]

2. Description of the Related Art Generally, casting of this type of aluminum composite material is performed by casting a molten metal, which is a mixture of aluminum and additive, into a mold through a sprue and pushing up a feeder on the opposite side. is doing. The state is shown in FIG.

That is, reference numeral 1 in the drawing is a mold comprising an upper mold 1a and a lower mold 1b. Into the mold 1, a funnel-shaped sprue 2, a pit-shaped basin (gate basin) 3 communicating with the lower end, a runner 4 extending horizontally from the basin 3, and a tip of the runner 4 And a funnel-shaped riser opening 6 that communicates with the cast metal forming portion 5 on the side opposite to the runner and rises. Further, a filtration chamber 7 is formed in the middle of the runway 4,
A porous filter plate 8 is attached here.

Then, the molten metal A of the mold 1 in which the aluminum and the additive are mixed is poured from the spout 2, and the molten metal A is filled into the casting molding part 5 through the runner 4, and the molten metal A is further filled in the spout 2. By pouring the molten metal and pushing up the feeder B in the feeder port 6, the cast product C of the aluminum composite material is cast.

[0005]

By the way, in recent years,
In order to obtain wear resistance and high rigidity of a cast product of an aluminum composite material, attempts have been made to mix aluminum (SiC) particles and perform casting. However, because of the rigidity of the casting product, it is necessary to sufficiently stir the powdery fine SiC particles to uniformly mix it with the aluminum melt, so the air and gas entrained in the melt during the stirring are required. Enters the molten metal pool 3 of the mold 1, the molten metal flow path 4 and the casting molding part 5 as they are, and as a result,
There is a problem that a sound casting product C cannot be formed due to the formation of cavities in the casting product C or the disturbance of the flow rate of the molten metal A.

The present invention has been made in view of the above circumstances. An object of the present invention is to ensure that even if an additive material is stirred and mixed in an aluminum melt and poured into a mold, air is not mixed into the casting and the flow velocity of the melt is disturbed. In addition, it is possible to obtain a sound casting product of a healthy aluminum composite material that is free from defects such as cavities, and is particularly suitable for casting of a casting product of an aluminum composite material in which SiC particles are stirred and mixed, and has extremely high wear resistance and It is an object of the present invention to provide a casting method and an apparatus therefor which are effective in realizing a light alloy brake disc rotor for automobiles and the like having excellent high rigidity.

[0007]

[Means for Solving the Problems] In order to achieve the above-mentioned object, the casting method of an aluminum composite material according to the present invention is a method of casting a molten metal of an aluminum composite material, in which an additive material is mixed with aluminum, from a sprue through a runner. In addition to pouring it into the mold, air is removed from the melt by a bubble trap in the middle of the runway leading from the sprue into the mold, and then the melt is poured into the mold while controlling the flow rate with a choke in the runway and pushed on the opposite side. It is characterized by casting an aluminum composite cast product by pushing up the hot water.

In order to make it possible to carry out the above-mentioned method, the casting apparatus for an aluminum composite material of the present invention pours a molten metal of an aluminum composite material, in which an additive material is mixed into aluminum, into a mold through a sprue and is provided on the opposite side. In an apparatus for casting a cast product of an aluminum composite material by pushing up a feeder, a bubble trap for removing air in the molten metal is provided in the runway leading from the sprue into the mold, and the melt is provided at the tip side of the runner. It is characterized in that a choke is provided to control the flow velocity of the molten metal by changing the cross-sectional area of the passage. The cross-sectional area of the choke is preferably set to about 0.55-0.9% of the cross-sectional area of the runner. Further, it is desirable to install a filter for removing impurities such as slag in the molten metal after the choke on the way of the runway leading from the sprue into the mold. Further, it is desirable to set the filter to have a mesh of 50 to 300.

[0009]

With the above-described method and apparatus for casting an aluminum composite material, when the molten aluminum composite material in which the additive material is agitated and mixed with the aluminum melt is poured into the mold through the runner, the agitation is performed.・ When pouring, the air and gas entrained in the molten metal are extracted by a bubble trap in the middle of the runway that leads from the spout to the mold, and the molten metal is flow controlled by a choke in the middle of the runway to ensure that the melt is appropriate. It becomes possible to cast an aluminum composite cast product by flowing into the mold at a constant flow rate and pushing up the riser on the opposite side. As a result, cavities are not generated in the casting product and the flow velocity of the molten metal is not disturbed, and a casting product of a sound aluminum composite material without defects such as cavities can be obtained. In particular, even if SiC particles with fine particles are stirred and mixed in an aluminum melt and poured into a mold, air and gas can be sufficiently vented, so it has excellent wear resistance and high rigidity without defects such as cavities. A sound aluminum-SiC composite casting product can be obtained.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the casting method and apparatus for an aluminum composite material according to the present invention will be described below with reference to FIGS. First, for convenience of description, the casting apparatus for an aluminum composite material will be described. As shown in FIG. 1, a funnel-shaped sprue 12 is provided in a mold 11 having a vertically divided structure including an upper mold 11a and a lower mold 11b, as in the conventional case. A pit-shaped basin (gate bottom) 13 communicating with the lower end, a runner 14 extending horizontally from the basin 13, and a casting molding part 15 communicating with the tip of the runner 14.
And a funnel-shaped riser opening 16 that communicates with the side of the cast metal forming portion 15 opposite to the runner and rises. A core 15a is mounted in the casting molding section 15.

Further, a bubble trap 17 for evacuating the air in the molten metal A is provided in the middle of the runway 14 of the mold 11.
A choke 18 that is located closer to the tip of the runner 14 than the bubble trap 17 and controls the flow velocity of the molten metal is formed.
Further, a filter chamber 19 is formed at a position closer to the tip of the runner 14 than the choke 18, and a filter 20 for filtering and collecting impurities such as slag in the molten metal is provided in the filter chamber 19. Here, the bubble trap 17 is a vertical shaft-like one that branches so as to rise straight from the runner 14.
The upper end is opened on the upper surface of the mold 11.

Further, the choke 18 is changed by squeezing the cross-sectional area D of the runner 14 so that the melt A of the runner 14 is changed.
The flow velocity of the choke 18 is controlled and the degassing effect of the bubble trap 17 is promoted. The ratio of the cross-sectional area E of the choke 18 to the cross-sectional area D of the runner 14 is
E / D is set within a range of about 0.55 to 0.9.
That is, as shown in FIG. 2, when the cross-sectional area ratio E / D is about 0.55 or less, the flow of the molten metal A in the runner 14 slows down and does not quickly flow into the casting molding part 15, and at the end of the casting molding part 15. A molten metal boundary is generated and a cast product C has cavities.
On the other hand, when the cross-sectional area ratio E / D is about 0.9 or more, the molten metal A quickly flows into the casting forming part 15 and entrains gas and air together, so that the casting product C also has cavities. Therefore, the choke 18 has a cross-sectional area ratio E / D of about 0.55 to the runner 14.
It is set within the range of 0.9 so that the molten metal A flows into the casting molding portion 15 at an appropriate flow rate so that the occurrence of a molten metal boundary and the entrainment of gas or air are eliminated.

Further, the filter 20 is of a "scrubber shape" using ceramic fibers and is set in a range of about 50 to 300 mesh. That is, this filter 2
As shown in Fig. 3, when SiC particles are mixed as an additive in the aluminum melt, a certain degree of mesh roughness (300 mesh or less) is required to maintain a sufficient passage rate of the SiC particles. If the mesh is finer than 300 mesh, the passage rate of the SiC particles is lowered, the rigidity of the casting product C is lowered, and the flow velocity of the molten metal is reduced due to the resistance of the molten metal flow. The molten metal boundary is generated at the terminal and the cast product C has a nest. On the other hand, when the mesh size is 50 mesh or more, the mesh is too coarse and impurities such as slag are allowed to pass through. Therefore, the filter 20 is selected in the range of about 50 to 300 mesh so as to ensure an appropriate flow rate of the molten metal and a sufficient passage rate of the SiC particles while preventing the mixing of impurities.

The addition amount of the SiC particles is 10 to 20% with respect to the aluminum, which is determined by the casting product. A portion of this added amount that has passed through the filter 20 remains in the casting product. Therefore, the addition amount of SiC particles is determined in consideration of the pass rate of the filter 20. The SiC particles usually have a particle size of several tens of microns, but a particle size of 10 to 100 μm can also improve the wear resistance and rigidity of the aluminum casting. By the way, it is difficult to disperse coarse SiC particles of about 10 microns or less evenly and mix them uniformly in the aluminum melt, and fine SiC particles of about 100 microns or more do notch the cast product and the rigidity is not increased.

For example, when 10 to 100 micron SiC particles are mixed with an aluminum melt and passed through a 300 mesh filter 20, the mesh size of the 300 mesh is about 85 micron. 100
Of the micron SiC particles, 86-100 micron SiC particles cannot pass, but other 10-85 micron SiC particles can pass, and the passing rate may be about 90% or more of the total addition amount.

A method of casting a cast product of an aluminum SiC composite material using the aluminum composite material casting apparatus (mold) having the above-mentioned structure will be described. First, 10 to 100 micron SiC particles as an additive material are added to an aluminum melt. ~ 20%
It is added and stirred and mixed, and the molten metal A containing SiC particles is poured from the gate 2 of the mold 1. As a result, the molten metal A flows from the hot water supply 12 through the hot water reservoir 13 through the runway 4, and partially invades the bubble trap 17 on the way, and gas and air float up and escape. Then go further on the runway 14 and choke 1
8 through which the flow of the molten metal A is controlled by the presence of the choke 18 and the flow velocity is slightly reduced, and the molten metal A further advances through the runner 14 and enters the filtration chamber 19. So filter 20
By this, impurities such as slag are filtered and collected, and in such a state, they flow into the casting molding part 15 and push up the feeder B of the feeder port 16 on the opposite side to fill the casting mold part 15 with the molten metal A. . As a result, the casting product C having the desired shape can be cast.

According to such a casting method, when the SiC particles are stirred and mixed in the aluminum molten metal, or when the molten metal A is poured into the spout 12, the air or the generated gas entrained in the molten metal A is melted. By controlling the flow velocity of the molten metal A due to the presence of the choke 18 in the bubble trap 17 along the way 14, the degassing effect in the bubble trap 17 is promoted, and the air and gas in the molten metal A are efficiently removed. Since the molten metal A will flow into the casting forming part 15 at a stable and appropriate flow rate, no molten metal boundary or cavities will be generated in the casting product C, and a sound aluminum SiC composite having no defects will be produced. The cast product C of the material can be obtained, the wear resistance can be increased by 60% compared with the conventional product, and it is about 1
0000 Kg f / mm ² High rigidity can be obtained.

Although the filter 20 is provided in the above-mentioned embodiment, the ratio E / D of the cross-sectional area E of the choke 18 portion and the cross-sectional area D of the runner 14 is about 0.55 or more. (No generation) and a low value, the flow velocity of the molten metal in the runway 14 decreases, and impurities such as slag precipitate in the pool 13, so the filter 20 can be omitted or the filtration capacity can be reduced. A small filter can be used, which can reduce costs and simplify maintenance.

[0019]

Since the method and apparatus for casting an aluminum composite material according to the present invention are as described above, even if the additive material is agitated and mixed in the molten aluminum and poured into the mold, air is not mixed into the casting. It is possible to reliably prevent the disturbance of the molten metal flow rate and obtain a sound casting product of a healthy aluminum composite material without defects such as cavities. Especially, it is most suitable for casting the casting product of aluminum composite material with stirring and mixing of SiC particles. It is effective for realizing a light alloy brake disc rotor for automobiles and the like, which has excellent wear resistance and high rigidity.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of an aluminum composite casting apparatus of the present invention.

FIG. 2 is a diagram showing the relationship between the molten metal flow velocity and the cross-sectional area ratio between the mold choke and the runner of the above-described embodiment.

FIG. 3 is a diagram showing the relationship between the mesh of the filter and the passage rate of SiC particles according to the embodiment.

FIG. 4 is a cross-sectional view showing a conventional casting apparatus for an aluminum composite material.

[Explanation of symbols]

11 ... mold, 12 ... sprue, 13 ... hot water pool, 14 ... runner,
15 ... Casting forming part, 16 ... Feeder port, 17 ... Bubble trap, 18 ... Choke, 19 ... Filtration chamber, 20 ... Filter,
A: molten metal, B: riser, C: cast product.

Claims (5)

[Claims] 1. A cast product of an aluminum composite material is cast by pouring a molten metal of an aluminum composite material, in which an additive material is mixed into aluminum, into a mold through a runner and pushing up a feeder on the opposite side. In the method, the air is removed from the molten metal by a bubble trap in the middle of the runway leading from the sprue into the mold, and then the molten metal is poured into the mold while controlling the flow rate by a choke in the runway. Method of casting wood. 2. An apparatus for casting a cast product of an aluminum composite material by pouring a molten metal of an aluminum composite material, in which an additive material is mixed into aluminum, into a mold through a sprue and pushing up a feeder on the opposite side. A bubble trap for removing air from the melt was provided in the middle of the runway leading from the sprue into the mold, and a choke was provided on the tip side of the runway to control the flow velocity of the melt by changing the cross-sectional area of the runway. Aluminum composite material casting equipment characterized by the following. 3. The aluminum composite casting apparatus according to claim 2, wherein the cross-sectional area of the choke is set to about 0.55 to 0.9% of the cross-sectional area of the runner. Material casting equipment. 4. The casting apparatus for aluminum composite material according to claim 2, wherein a filter for removing impurities such as slag in the molten metal is provided after the choke in the runway leading from the sprue into the mold. Aluminum composite material casting equipment. 5. The casting apparatus for an aluminum composite material according to claim 4, wherein the filter is set to have a mesh of 50 to 300 mesh.