| 摘要 |
PURPOSE:To promote the improvement of a cylinder in the viewpoint of its design, by forming the cylinder by an aluminum tube providing an outer oxidized film of hardness less than 350HV in the external surface while an inner oxidized film of hardness of 350HV or more in the internal surface. CONSTITUTION:A cylinder tube is constituted of an aluminum tube 2 providing an outer oxidized film 3 of normal or half hardness less than 350HV in the external surface while an inner oxidized film 4 of hardness or super hardness not less than 350HV in the internal surface. The outer oxidized film 3 is transparent, and the tube 2, showing its appearance in silver or bright gray color, can be colored in the colorful tone containing a primary color system by further performing electrolytic coloring or inorganic and organic dyeing. |
