JP3327295B2 - Electrical surface treatment method for aluminum wheel material for automobiles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an automatic casting product.
The present invention relates to a method for performing an electrical surface treatment on the surface of a vehicle wheel material .

[0002]

2. Description of the Related Art A casting is formed by pouring a molten metal into a mold formed in a required shape and solidifying it into a shape along the mold.

[0003] Therefore, in general, an article having a complicated shape that is difficult to manufacture by means of machining or the like is often formed by casting, and in casting, the shape of the surface formed by the mold is important. is there.

[0004] Even in such a casting, it is sometimes necessary to perform an electrical surface treatment on the surface of the casting because it is necessary to improve the appearance.

[0005] However, the casting is formed by solidification of the molten metal in the mold as described above. Since the surface of the casting first solidifies by solidification, the solidification of the casting starts. Is a state rapidly cooled from the inside of the casting, and additional elements and compounds often precipitate on the casting surface, which is the surface of the casting.

[0006] Since most of the precipitates on the casting surface are electrically poor conductors, it is generally difficult to perform good electrical surface treatment on the casting surface of the casting. The stereotype that there was was formed.

[0007]

SUMMARY OF THE INVENTION The present invention relates to a casting product.
It was made based on the notion that it is difficult to perform good electrical surface treatment on the casting surface of automobile wheel material , and the surface shape that is important as an automobile wheel material not impaired, it is an object to perform good electrical surface treatment on the skin cast.

[0008]

In order to achieve this object, an invention according to claim 1 is characterized in that a casting surface constituting a design surface of an aluminum wheel material for an automobile is sprayed,
An electroplating process is performed on the processed surface.

[0009]

According to the first aspect of the present invention, an automobile wheel is provided.
Since the spraying process is performed on the casting surface that constitutes the design surface of the metal material, deposits etc. attached to the casting surface are removed, and the presence of electrically poor conductors on the casting surface is reduced,
It is possible to evenly energize the casting surface that constitutes the design surface of this automotive wheel material , and a good electrical surface treatment
Can do it.

[0010] Since the deposits on the casting surface are removed by spraying, the surface shape, which is important as a material for automobile wheels , is hardly impaired.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described with reference to an embodiment shown in the drawings.
In this case, shot peening as spraying is performed on the design surface of the aluminum wheel material for automobiles formed by casting of the material, and alumite treatment is performed on the design surface as electrical surface treatment.

Note that the design surface is a surface facing the outside of the vehicle body when the vehicle aluminum wheel is mounted on the vehicle, and is a portion constituting a part of the appearance of the vehicle.

In this embodiment, the aluminum alloy material is poured into a predetermined die, solidified and then removed from the mold, the gate is removed, and an aluminum wheel material for an automobile having a substantially predetermined shape (hereinafter simply referred to as simply). 11).

First, the wheel 11 shifts to a shot peening process as a spraying process.

The processing conditions in this shot peening step are, for example, as shown in Table 1.

[0016]

[Table 1]

[0017] Under such conditions, as shown in FIG. 2, shot peening is performed for about 20 minutes over the entire wheel 11 using one shot nozzle.

The shot peening processing is a processing method having a relatively high degree of freedom, in which shots are sprayed substantially uniformly on the entire outer surface of the wheel 11 formed of various large and small curved surfaces, and the surface is subjected to alumite processing described later. A certain design surface 12 is sprayed particularly carefully.

As a result, foreign substances such as precipitates adhering to the casting surface of the wheel 11 are removed, and particularly, foreign substances on the design surface 12 are almost completely removed.

In particular, the air blowing type shot peening used in this embodiment is characterized in that a shot nozzle 13 for injecting a shot toward a wheel 11, which is a workpiece,
Since the compressed air and the shot are supplied via the compressed air hose 14 and the shot hose 15 each made of a flexible material, the direction and position of the shot nozzle 13 can be freely adjusted. The degree of freedom of the shot peening process on the outer surface of the wheel 11 formed by the curved surface is extremely high.

Although FIG. 2 shows a case where one shot nozzle 13 is used, if a plurality of shot nozzles are used in combination, the shot peening processing time can be reduced. .

The surface of the design surface 12 of the wheel 11 that has undergone such shot peening becomes a fine ground-like uneven surface, and a plastic deformation layer is formed on the surface layer.

In particular, in the shot peening process in this embodiment, the kinetic energy of the shot is high because the shot spraying speed is high as described above, so that the thickness of the plastic deformation layer is about 1.5 mm to 3.0 mm. And has become larger.

The present invention can be carried out under other shot peening conditions, and it goes without saying that, besides this shot peening process, a spraying process such as sandblasting or liquid honing may be used.

Thereafter, the wheel 11 is shifted to a machining step, in which a required portion is machined to form an accurate predetermined shape as the wheel 11.

After this machining step, in this embodiment, a polishing step is performed on the design surface 12 to form an extremely smooth alumite coating on the surface in a later step.

This polishing step is a buff polishing with a buff using an appropriate compound. Although the margin of the surface is very small and the metallographic structure is still cast, the shot peening is performed prior to the buff polishing. Since it is processed, a sufficiently good finished surface can be obtained by buffing.

Thereafter, the wheel 11 goes through a degreasing step and a washing step sequentially.

It should be noted that, depending on the casting product, it may be possible to directly shift to the degreasing step without going through the machining step or the polishing step.

The degreasing step is performed by immersion in a treatment liquid of a commercially available aluminum cleaner. After immersion for a predetermined time, the treatment liquid adhered to the wheel is removed in a washing step with washing water.

Thereafter, the wheel 11 shifts to an alumite treatment step as an electrical surface treatment.

This alumite treatment is carried out using a known alumite equipment. For example, an aqueous solution of 180 g / l sulfuric acid is used as an electrolytic solution, the solution temperature is kept at + 5 ° C., the current density is 3 A / dm ² , and the film thickness is Until 20 microns.

In the alumite treatment step, the precipitate on the design surface 12 made of the casting surface is removed by the shot peening process as described above. And an alumite film having a uniform thickness can be formed on the entire design surface 12.

After this alumite treatment, the design surface 12
The wheel 11 on which the alumite coating 2 is formed is washed with water and dried with warm air at 60 to 70C.

The alumite film thus formed is a so-called hard alumite film having a hardness higher than the Vickers hardness Hv350, and the surface of the alumite film has a diameter of 100 to 300 angstroms. One hundred millions of pores having openings are formed per cm ² .

In this embodiment, such an alumite film is subjected to the following coloring treatment.

That is, in this coloring treatment, for example, the coloring material obtained by dissolving oil-based dye 4 (trade name: Oil Color) manufactured by Orient Co., Ltd. in a volatile solvent such as acetone, cyclohexanone or toluene is filtered. The coating is applied by brushing or immersion to fill the pores, wipe off the excess, and then dry with hot air.

Thereafter, a sealing treatment is performed to prevent leakage of the dye from the pores.

The sealing treatment in this embodiment is performed by dipping a 7 g / liter nickel acetate aqueous solution at 80 to 95 ° C. for 20 minutes.

It should be noted that the temperature of distilled water was set to 90 to 100 ° C.
It may be soaked for a minute, or may be sealed with steam.

Since the black dye is filled in the pores of the alumite film thus formed and the cracks opened on the surface, the transparent or translucent alumite film is formed by these pores. Alternatively, the reflected light from the dye in the crack is scattered in the alumite coating, and looks black when viewed from the surface.

Thereafter, the surface of the alumite film subjected to the sealing treatment is subjected to a polishing step.

In this polishing step, Rma having been subjected to the sealing treatment is used.
The surface of the alumite film of x 1.5S is finished to a smooth surface of Rmax 0.1S using a grinding wheel or a polishing wheel, and polishing is performed by a vertical grinder using cooling water.

The allowance of the alumite film in this polishing step is about 5 μm or less, and the allowance is very small, so that the dye in the pore does not leak out of the alumite film and the surface of the alumite film is smooth. Finished.

In the above-described embodiment, the case where the alumite film formed on the surface of the design surface 12 is colored has been described. However, in the present application, the coloring step may be omitted.

Further, in this embodiment, an alumite treatment has been described as an electric surface treatment, but the present invention can be carried out even with other electric surface treatments such as electroplating and electrolytic polishing. The present invention can be similarly applied to other castings such as automobile wheels made of a magnesium alloy.

[0047]

As described above, according to the first aspect of the present invention, according to the first aspect of the present invention, the casting surface as the design surface of the wheel material for an automobile is sprayed. Precipitates attached to the top are removed, and the presence of electrically poor conductors on the casting surface is reduced,
It can be equally energized the casting surface, good electrical message
It is possible to perform the can processing.

Since the deposit on the casting surface is removed by the spraying process, the surface shape of the casting is hardly impaired, and the important meaning as a design surface of the wheel material for automobiles is not impaired.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a manufacturing process of a wheel as an embodiment of the present invention.

FIG. 2 is an explanatory diagram of a situation of a shot peening process.

[Explanation of symbols]

 11 Aluminum wheels for automobiles 12 Design surface 13 Nozzle for shot

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C25D 11/00-11/34 C25D 5/00-7/12 B22D 29/00

Claims (2)

(57) [Claims] An electric surface treatment method for an aluminum wheel material for an automobile, comprising: spraying a casting surface constituting a design surface of an aluminum wheel material for an automobile, and performing electroplating on the processed surface. . 2. The method according to claim 1, wherein the spraying is performed by shot peening.