KR20070017779A - Method for manufacturing road wheel for automobile - Google Patents

Abstract

The present invention relates to a method for manufacturing a road wheel for an automobile, wherein a product is manufactured by using an aluminum alloy casting material for a road wheel formed by partially adjusting a component and a content of a material in order to improve moldability and strength. By molding using a liquid forging method that is injected into the chamber and pressurized to a high pressure, it is possible to obtain an effect of shortening the cycle time, and to expect an effect of improving productivity and improving material yield, and forming a high pressure and rapid cooling. The present invention relates to a method for manufacturing a road wheel for an automobile capable of greatly improving strength and elongation by miniaturization of tissue.

According to the present invention, it is possible to achieve a uniform quality and light weight of the product compared to the existing low-pressure mold casting method, through which it is possible to expect the effect of improved driving and ride comfort, the degree of freedom (Net Shape possible) is superior to the existing method This has the advantage of reducing component machining losses.

Automotive, Road Wheels, Aluminum Alloys, Casting, Liquid Forging, Low Pressure Casting

Description

Method for manufacturing road wheel for automobile}

1 is a schematic view showing a low pressure die casting device for manufacturing a conventional aluminum rod wheel,

Figure 2 is a schematic diagram showing a casting apparatus used in the road wheel manufacturing process of the present invention,

Figure 3 is a photomicrograph of the structure of the existing molded product produced by the low pressure mold casting method and the present invention.

<Explanation of symbols for the main parts of the drawings>

11: heating furnace 12: infusion cup

13: mold 14: cavity

15: up and down drive device (hydraulic cylinder) 16: upper punch

17: Up and down drive device (hydraulic cylinder) 18: Lower punch

19: cooling water tank

The present invention relates to a method for manufacturing a road wheel for an automobile, and more particularly, to manufacture a product using an aluminum alloy casting material for a road wheel formed by adjusting a part and content of a material in order to improve moldability and strength. By injecting the molten alloy into a mold and molding using a liquid forging method, which is pressurized to a high pressure, the cycle time can be shortened, and productivity and material yield can be improved. The present invention relates to a method for manufacturing a road wheel for an automobile capable of greatly improving strength and elongation by forming a structure and minimizing it by rapid cooling.

In general, automotive road wheels are manufactured by melting an aluminum alloy casting material by a low pressure die casting process.

1 is a schematic view showing a low pressure die casting apparatus for manufacturing a conventional aluminum rod wheel, a process of manufacturing a road wheel using the same as follows.

First, after dissolving the aluminum alloy, the aluminum alloy molten metal is injected through the molten metal injection port 1 to fill the crucible furnace 2.

Then, when pressurized gas is injected through the gas inlet 3 while the mold is closed, the molten metal of the crucible furnace 2 is driven by the gas pressure through the upper inlet 5 and the lower mold 6 through the inlet 4. The inside of the cavity 7 of the formed product shape is filled.

Then, after the aluminum alloy injected into the cavity 7 is hardened to some extent, the movable plate 8 is operated to open the upper mold 5, and then the product is demolded.

Thus, when the aluminum alloy casting material is used, the manufacturing method of the road wheel is mostly mass-produced by the low pressure die casting method.

However, in the case of using the above-mentioned low pressure mold casting method, it may be a problem in quality due to the generation of internal pores during casting, and also the cycle time is usually about 6 minutes due to the slow cooling rate, which reduces the productivity of the product. And there is a problem that the yield of the material is vulnerable.

As described above, when the aluminum road wheel is manufactured using the low pressure die casting method, the cycle time may be longer, and the riding comfort and the steering stability may be reduced when the vehicle is driven due to uneven casting quality and high weight of the product.

Therefore, the aluminum alloy casting material is used to produce some parts by applying the melt casting method (squeeze casting), but the molten casting method has the effect of producing light weight parts compared to the existing low pressure casting parts, but the equipment cost is high In addition, the yield is about 50%, which is a problem in terms of productivity.

Therefore, the present invention was invented to solve the above problems, but to manufacture a product using an aluminum alloy casting material for the road wheel, which is formed by adjusting the composition and content of the material to improve the formability and strength, aluminum alloy By injecting the molten metal into the mold and molding using a liquid forging method, which is pressurized at high pressure, the cycle time can be shortened, and productivity and material yield can be improved. And to provide a method for manufacturing a road wheel for an automobile that can greatly improve the strength and elongation by the microstructure of the tissue by rapid cooling.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

The present invention is a manufacturing method of a road wheel for automobiles,

Mainly based on aluminum (Al), silicon (Si) 6.5 to 7.5 wt%, magnesium (Mg) 0.25 to 0.45 wt%, iron (Fe) 0.25 wt% or less, copper (Cu) 0.1 wt% or less, manganese Dissolving an aluminum alloy casting material containing (Mn) 0.1 wt% or less, titanium (Ti) 0.05-0.15 wt%, and beryllium (Be) 0.15-0.25 wt%;

Measuring the molten metal of the aluminum alloy casting material according to the weight of the product and then injecting the molten metal into the cavity of the mold using an injection cup;

Lowering the upper punch operated by the hydraulic cylinder to pressurize the molten metal injected into the cavity while controlling the lowering operation of the upper punch;

Maintaining the pressure for a predetermined time after the pressing and then raising the upper punch to open the mold, and then taking out the product;

Quenching the extracted product in a cooling water bath;

Characterized in that it comprises a.

Here, after injecting the aluminum alloy molten metal into the cavity at 670 ℃, while controlling the descending speed of the hydraulic cylinder to 0.05m / sec and at the same time press the molten metal to a pressure of 100MPa with an upper punch, and then the pressure for 20 seconds It is characterized in that the product is taken out after maintaining.

In addition, the extracted product is immersed in a cooling water tank having a water temperature of 70 ℃ quenched for 10 seconds.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

First, the present invention uses a material composition for automobile road wheels made by adjusting a part of the material component to improve the formability and strength, the composition and content thereof are shown in Table 1 below.

As shown in Table 1, the aluminum alloy casting material for a road wheel according to the present invention is based on aluminum (Al), wherein silicon (Si) 6.5 ~ 7.5 wt%, magnesium (Mg) 0.25 ~ 0.45 wt%, iron (Fe) 0.25 wt% or less, copper (Cu) 0.1 wt% or less, manganese (Mn) 0.1 wt% or less, and titanium (Ti) 0.05 to 0.15 wt%, and beryllium (Be) 0.15 to 0.25 wt% will be.

First, in the case of silicon, as an element added to give an effect of improving castability and strength, it is added at 6.5 to 7.5% by weight, and if added to less than 6.5% by weight there is a problem that the castability and strength is lowered If the content is added in excess of 7.5% by weight, some silicon segregation may occur, which is not preferable.

Next, magnesium provides an effect of improving the strength by producing a precipitate with silicon at the time of heat treatment, in the present invention is added at 0.25 ~ 0.45% by weight.

Here, when the amount of magnesium added is less than 0.25% by weight, there is a problem that the intermetallic compound (Mg ₂ Si) formed by reacting with silicon during heat treatment is insufficient and the strength is lowered. This is not preferable because the elongation is lowered due to excessive formation of an intermetallic compound (Mg ₂ Si) during heat treatment.

Next, in the case of iron, the addition amount is suppressed to 0.25% by weight or less, because iron combines with aluminum and silicon to produce a weak precipitate.

In addition, copper and manganese also combine with aluminum and silicon to produce a weak precipitate, the content is suppressed to less than 0.1% by weight.

Next, titanium is an element that provides an effect of improving castability and strength through grain refinement at an initial stage. In the present invention, titanium is added in an amount of 0.05 to 0.15% by weight. There is a problem that the strength and castability improvement effect is small, and when added in excess of 0.15% by weight, there is a problem during processing due to the formation of excessive intermetallic compound, it is not preferable.

In addition, beryllium is an element that enhances formability and matrix structure and improves strength, and is added in an amount of 0.15 to 0.25 wt%.

If beryllium is added in less than 0.15% by weight, there is a problem that the matrix structure reinforcing effect is insufficient, and when added in excess of 0.25% by weight, the strength is improved but the elongation is lowered, which is not preferable.

On the other hand, the present invention provides a method for integrally forming an aluminum rod wheel using a liquid forging method in order to solve the problems caused by the conventional low pressure mold casting method.

In manufacturing a road wheel using the liquid forging method, an aluminum alloy casting material having the composition shown in Table 1 is used, and the apparatus shown in FIG. 2 is used.

Figure 2 is a schematic diagram showing a casting apparatus used in the manufacturing process of the road wheel of the present invention, the casting apparatus as shown to form a product while pressing the molten metal at a high pressure in the state in which the aluminum alloy molten metal is injected into the cavity of the mold It is.

Looking at the configuration, the casting apparatus used in the present invention, the injection cup 12 for injecting the molten metal into the cavity 14 of the mold 13, the mold 13 having a cavity of the product shape, and up and down driving The upper punch 16 which pressurizes the molten metal injected into the said cavity 14 from the upper side at the time of a lowering operation, and is made to move up and down on the upper side of the metal mold | die 13 by the apparatus (hydraulic cylinder) 15, and the up-and-down And a lower punch 18 which pushes and lowers the mold 13 under the mold 13 by a driving device (hydraulic cylinder) 17 to push the molded product out of the mold 13 during the ascending operation. .

Referring to the process of manufacturing a road wheel using such a casting apparatus in order as follows.

First, the aluminum alloy cast material having the composition shown in Table 1 above is dissolved and maintained at 700 ° C. in the thermal furnace 11.

Thereafter, the molten metal in the thermal furnace 11 is weighed according to the product weight, and then moved to the injection cup 12, and the weighed aluminum alloy molten metal is injected into the cavity 14 of the mold 13 at 670 ° C. FIG.

After the molten metal is injected into the cavity 14, the hydraulic cylinder 15 is operated to lower the upper punch 16, and to be in close contact with the mold 13.

Next, the molten metal injected into the cavity 14 of the metal mold 13 is pressed by the upper punch 16 while precisely controlling the lowering operation of the hydraulic cylinder 15.

At this time, the lowering speed of the hydraulic cylinder (upper punch) 15 is controlled to 0.05 m / sec and the upper punch 16 presses the molten metal to a high pressure of 100 MPa.

After the pressurization is performed as described above, the pressure is kept constant for about 20 seconds, and then the upper punch 16 is raised to open the mold 13, and then the lower punch 18 is operated upward to operate the product. Take out.

Subsequently, after the product is taken out, it is immediately immersed in a cooling water tank 19 having a water temperature of 70 ° C. and quenched for about 10 seconds and then taken out (strength improvement effect).

As described above, in the present invention, the product is manufactured using an aluminum alloy casting material having the composition shown in Table 1 above, and the cycle time is formed by injecting the aluminum alloy molten metal into the mold and then molding using a liquid forging method of pressurizing at high pressure. The effect of shortening (about 70 seconds) to about 1/5 can be obtained, and the effect of improving productivity and material yield can be expected, and the strength and elongation can be greatly improved by miniaturizing the tissue by high pressure molding and rapid cooling. do.

In addition, it is possible to achieve uniform quality and light weight of the product compared to the existing low pressure mold casting method (about 30% weight reduction), and through this, it is possible to expect the effect of improved driving and riding comfort, and freedom of shape compared to the existing method (Net Shape is possible). ) Has the advantage of reducing the loss of machining parts.

Hereinafter, the present invention will be described in more detail with reference to the following examples, but the present invention is not limited to the following examples.

Example  And Comparative example

As an example, an aluminum rod wheel was manufactured according to the manufacturing process of the present invention (liquid forging method) using the aluminum alloy casting material having the composition shown in Table 2, wherein the casting apparatus of FIG. Each process condition such as conditions, product cooling conditions, etc. were prepared in the same manner as the process conditions described above.

In addition, as a comparative example, an aluminum rod wheel (existing mass production) was manufactured by applying the existing low pressure die casting method using an aluminum alloy casting material having the composition shown in Table 2 below (existing material: A356.0). Made to the same shape and size as the road wheel.

First, the tissue of the product manufactured by the Example and the comparative example was observed by microscope, and FIG. 3 is a microscope picture of an Example and a comparative example, and is 200 times enlarged photograph.

Looking at the comparison of the two photos, it can be seen that the tissue in the product of the embodiment is more fine compared to the existing product of the comparative example.

On the other hand, when applying the present invention in order to verify that the physical properties of the product can be further improved compared to the conventional mass-produced products, the tensile strength, elongation, and hardness for the road wheels of the examples and comparative examples manufactured as described above Each was measured.

In this case, for each road wheel, the parts, that is, spoke (spoke) and the rim (rim) region was measured separately, the measurement results are shown in Table 3 below.

As can be seen from the results of Table 3, the tensile strength, elongation, and hardness were all improved in the case of the Example compared to the comparative example.

As described above, according to the method for manufacturing a road wheel for automobiles according to the present invention, the following effects are obtained.

In order to improve the formability and strength, the product is manufactured using aluminum alloy casting material which is made by adjusting part and content of the material, and the liquid forging method which injects the aluminum alloy molten metal into the mold and pressurizes it at high pressure. By shaping, the effect of shortening the cycle time to about 1/5 (70 seconds) can be obtained, and the effect of improving productivity and material yield can be expected. And elongation can be greatly improved.

In addition, it is possible to achieve uniform quality and light weight of the product compared to the existing low pressure mold casting method (about 30% weight reduction), and through this, it is possible to expect the effect of improved driving and riding comfort, and freedom of shape compared to the existing method (Net Shape is possible). ) Has the advantage of reducing the loss of machining parts.

Claims (3)

In the manufacturing method of a road wheel for automobiles, Mainly based on aluminum (Al), silicon (Si) 6.5 to 7.5 wt%, magnesium (Mg) 0.25 to 0.45 wt%, iron (Fe) 0.25 wt% or less, copper (Cu) 0.1 wt% or less, manganese Dissolving an aluminum alloy casting material containing (Mn) 0.1 wt% or less, titanium (Ti) 0.05-0.15 wt%, and beryllium (Be) 0.15-0.25 wt%; Measuring the molten metal of the aluminum alloy casting material according to the weight of the product and then injecting the molten metal into the cavity of the mold using an injection cup; Lowering the upper punch operated by the hydraulic cylinder to pressurize the molten metal injected into the cavity while controlling the lowering operation of the upper punch; Maintaining the pressure for a predetermined time after the pressing and then raising the upper punch to open the mold, and then taking out the product; Quenching the extracted product in a cooling water bath; Method of manufacturing a road wheel for cars comprising a. The method according to claim 1, After injecting the aluminum alloy molten metal into the cavity at 670 ° C., while controlling the descending speed of the hydraulic cylinder to 0.05 m / sec, while pressing the molten metal at a pressure of 100 MPa with an upper punch, the pressure was kept constant for 20 seconds. Method of manufacturing a road wheel for an automobile, characterized in that after taking out the product. The method according to claim 1 or 2, The extracted product is immersed in a cooling water tank having a water temperature of 70 ℃ quenched for 10 seconds, characterized in that the manufacturing method of the vehicle road wheel.

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