JP3024390B2 - Manufacturing method of forged aluminum wheels with excellent corrosion resistance and fatigue strength - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a forged aluminum wheel having excellent corrosion resistance and fatigue strength used for a large vehicle or an ultra-high speed vehicle.

[0002]

2. Description of the Related Art Aluminum alloys are light and have an oxide film formed on the surface and have excellent corrosion resistance, so they are used for various machines and devices. Used in

[0003] Although aluminum alloys have good corrosion resistance, it is known that an electrochemical reaction occurs at an interface between a crystallized substance and a matrix in a certain area of a product depending on the use environment, causing pitting corrosion. This pitting corrosion is due to the fact that the interface between the crystallized substance and the matrix is exposed to the use environment. Therefore, the pitting can be suppressed by wrapping these interfaces with the matrix. As a method of covering the starting point of the pitting corrosion from the use environment, a method of applying a wash primer or a zinc chromate paint to the product surface has been adopted.

[0004] In addition, depending on the use conditions, fatigue cracks may occur on the surface of the wheel disk or the tip of the pit, which is a source of stress concentration, depending on the use conditions of the aluminum wheel. Since the opening of the fatigue crack occurs on the tensile side, the progress of fatigue can be suppressed by applying a compressive residual stress in advance.
As a method of applying this compressive residual stress, shot peening, grit blasting, liquid honing or the like is used to spray particles of several mm to several μm on the product surface, thereby giving compressive residual stress and improving the fatigue limit. .

[0005] In the production of forged aluminum wheels, the surface is generally coated with zinc chromate paint, and the application of compressive residual stress is performed by shot peening.

[0006]

However, the above-mentioned shot peening method has a disadvantage that it cannot be applied to a product having a complicated shape in addition to a large facility. Further, although the application of a zinc chromate paint is effective in preventing the occurrence of pitting corrosion, the effect of suppressing fatigue cracking is not sufficiently obtained. Further, it is said that the residual stress of the product has the effect of suppressing the growth of cracks on the compression side, but has an adverse effect on the corrosion resistance.

[0007] corrosion resistance this invention, which can impart compressive residual stresses as well as work hardening the entire aluminum ho <br/> eel surface using an apparatus made the ones, a simple configuration in order to solve the above problems -It is intended to provide a method for manufacturing a forged aluminum wheel having excellent fatigue strength.

[0008]

In order to achieve the above object, a method for manufacturing a forged aluminum wheel excellent in corrosion resistance and fatigue strength according to the present invention is provided by: A rotary ball or roller is pressed with a pressure of cm ² , and the impact energy at that time causes work hardening of the entire aluminum wheel surface and imparts compressive residual stress, and plastic flow of the entire aluminum wheel surface causes the crystal to become the starting point of corrosion. This is to wrap the location of the product or the like with a matrix.

[0009]

[Action] By practice of the present invention, an integral whole pressure of 170~230kgf / cm ² surface of the forged aluminum wheel, so to press the rotating balls or rollers, uniformly throughout the aluminum wheel table <br/> surface And it can be wrapped with a matrix well. In addition, the pressing at this time can work-harden the entire surface and impart compressive residual stress.

[0010] The pressure at the time of pressing the rotating balls or rollers to the whole aluminum wheel surface, is less than 170kgf / cm ²
Compressive residual stress Ru short of Ru improve the durability of the aluminum wheel is not obtained, and because fashion of the whole aluminum wheel <br/> Lumpur surface is impaired exceeds 230 kgf / cm ^2, 170
It limited to the range of ~230kgf / cm ^2.

[0011]

[Example] Rim width 19
An integrated forged aluminum wheel with 0.5mm and rim diameter of 571.5mm was manufactured. And the pressure on the whole aluminum wheel surface
The rotary ball was pressed at 200 kgf / cm ^{2 at} a feed rate of 20 mm / min. As a result, the entire aluminum wheel surface 20 Kgf / mm ²
Was able to be applied. In addition, the hardness of the entire aluminum wheel surface was higher than that before the ball was pressed, and it was confirmed that work hardening was performed.

A fatigue test of the product aluminum wheel according to the above embodiment was performed together with a comparative example. The result is shown in FIG.
That is, as the Examples and Comparative Examples of the present invention (A), Al
Multiplied by the shot blast to the entire actual wheel surface
(B), it was subjected to the fatigue test for aluminum on the entire wheel surface that has been subjected Jin chromate paint (C) and remain those not subjected to a surface treatment with the forging (D). From this figure, it can be seen that (A) according to the embodiment of the present invention has improved fatigue strength as compared with other comparative examples.

[0013] it was carried out above the product aluminum Wheel <br/> Le embodiment of the present invention, the investigation of Kazodo polarization curves for those of still forged as a comparative example. The result is shown in FIG. From this figure, it can be seen that the corrosion resistance is significantly improved by implementing the present invention.

[0014]

According to the present invention, when a simple apparatus of a rotary ball or a roller is used to press the entire surface of a forged aluminum wheel, a conventional apparatus using a conventional zinc chromate coating and a shot blasting method is used. Excellent corrosion resistance and fatigue strength equivalent to or better than

[Brief description of the drawings]

FIG. 1 is a graph showing the results of a fatigue test performed on an example of the present invention and a comparative example.

FIG. 2 is a graph showing cathode polarization curves of an example of the present invention and a comparative example.

[Explanation of symbols]

A Forged aluminum wheel according to an embodiment of the present invention B Forged aluminum wheel surface-treated by shot blasting C Forged aluminum wheel whose surface is coated with zinc chromate D Forged aluminum wheel as forged

──────────────────────────────────────────────────続 き Continuation of the front page (72) Katsuhiko Akazaki, Inventor 5-1-1109, Shimaya, Konohana-ku, Osaka-shi, Osaka Sumitomo Metal Industries, Ltd. Steel Works (56) References JP-A-59-84692 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) B23P 9/04 B60B 7/00

Claims (1)

(57) [Claims] 1. A pressing rotary ball or roller across a pressure of 170~230kgf / cm ² surface of the aluminum wheel formed with integral forging, A by the impact energy when the
Corrosion resistance and fatigue characterized by work hardening the entire surface of the Lumi wheel and imparting compressive residual stress, and plastically flowing the entire surface of the aluminum wheel to wrap the locations of crystallization, etc., which are the starting points of corrosion, with a matrix. Manufacturing method of forged aluminum wheels with excellent strength.