| 摘要 |
PURPOSE:To improve the heat conductivity and the lubrication effect of a steel pipe in its internal peripheral surface and peripheral surface, by mounting cylinders, drilling various kinds of pattern holes to be provided, to be attached to the internal peripheral surface and the peripheral surface of the steel pipe thereafter electrically etching a part of the internal peripheral surface and the peripheral surface of the steel pipe. CONSTITUTION:For using a steel pipe as a liner, it is necessary to respectively form the peripheral surface to a rugged part having a profile with a casting effect further the internal peripheral surface to a rugged part with a lubrication effect. Here the steel pipe 1 mounts to its peripheral surface side a cylinder 2 having a pattern A further to the internal peripheral surface side a cylinder 3 having a pattern B. And the manufacturing method, placing the steel pipe 1 in an electrolytic solution and applying a DC potential between each electrode 4, 5 and the steel pipe 1, provides a hollow by dissolving an iron amount from a surface (only a hole part) of the steel pipe 1 (serving as an anode). In this way, the steel pipe respectively enables the peripheral surface to attain the improvement of casting closeness and heat conductivity while the internal peripheral surface to attain the improvement of wearing resistance by a supply effect of lubricating oil. |
