Wheel nut and method of manufacturing wheel nut

1. A method of manufacturing a wheel nut, comprising:

annealing an aluminum (Al) alloy material;

preheating the annealed Al alloy material;

forging the preheated Al alloy material, to form a wheel nut;

performing an anodizing treatment to form a primary coating on the wheel nut;

performing a vacuum deposition to form a secondary coating on the wheel nut, which was subjected to primary coating; and

performing a surface treatment using a powder paint to form a tertiary coating on the wheel nut, which was subjected to secondary coating,

wherein the anodizing treatment, the vacuum deposition and the surface treatment are performed in sequence, and

wherein the annealing is performed via treatment at about 380˜420° C. for about 2˜5 hr and includes furnace cooling.

2. The method of claim 1 , wherein the Al alloy material is composed of Al and comprises: about 0.16-0.28 wt % chromium (Cr), about 1.2˜2.0 wt % copper (Cu), about 0.5 wt % or less iron (Fe), about 2.1˜2.9 wt % magnesium (Mg), about 0.3 wt % or less manganese (Mn), about 0.4 wt % or less silicon (Si), about 0.2 wt % or less titanium (Ti), about 5.1˜6.1 wt % zinc (Zn) and other potential impurities.

3. The method of claim 1 , wherein the preheating the annealed Al alloy material is performed at about 200˜300° C.

4. The method of claim 1 , wherein the performing the anodizing treatment forms an anodizing layer having a thickness of about 20˜70 μm.

5. The method of claim 1 , wherein the performing the anodizing treatment to form the primary coating further includes subjecting the wheel nut to a PEO (Plasma Electrolytic Oxidation) coating.

6. The method of claim 1 , wherein the performing the vacuum deposition forms a coating layer having a thickness of about 2˜10 μm.

7. The method of claim 1 , wherein the performing the surface treatment to form the tertiary coating includes using an acrylic powder paint to form a coating layer having a thickness of about 20˜50 μm.