Method of surface treatment on metal object and metal object with gradual patterns

A method of surface treatment on surface of metal objects, comprising the following steps:

• step 1:
• preparing multiple releasing sheets:
• each releasing sheet having at least one hollowed pattern, the hollow patterns of all of the releasing sheets forming a figure;
• step 2:
• attaching the releasing sheet 20:
• attaching one releasing sheet on a surface of a metal object which is a metal tube, a metal object, a metal plate or a bicycle frame;
• step 3:
• surface grinding:
• using a sandwheel to grind the surface of the metal object on which the releasing sheet is attached, the sandwheel removing material on the surface of the metal object via the hollowed pattern so as to form a treatment face which is shaped the same as the hollow pattern;
• step 4:
• removing the releasing sheet, and
• step 5:
• repeating the steps 2 to 4:
• the releasing sheet being attached to the surface of the metal object of each of the repeated steps 2 being different from the previous one, the sandwheels for grinding the surface of the metal object corresponding to the different releasing sheets having different roughness so as to obtain multiple treatment faces of different smoothness, the multiple treatment faces forming the figure;
• the surface of the metal object being ground by a sandwheel with different roughness from those of the sandwheels in steps 3 to 5 before the first releasing sheet is attached to the metal object to form multiple first treatment faces on the surface of the metal object, the first treatment faces having different smoothness to make the figure to have gradual effect visually.