| 摘要 |
PURPOSE:To make it possible to obtain a cylinder stock having an excellent surface smoothness, by subjecting the outer surface of a pipe successively to buff polishing, degreasing, caustic cleaning and water washing which are indispensable pretreatments for a squeezing process such as pipe extrusion or the like. CONSTITUTION:An extruded aluminum pipe is cut into pieces each having a predetermined length, and one end of the each pipe piece is subjected to a curl bending process as necessary. Thereafter, the outer surface of the predetermined length pipe piece 2 is buffed by a soft buff such as cotton buff or the like together with an abrasive such as tripoli or the like. Then, die traces 4 intrinsic to the pipe are completely removed, but instead, a wax component contained in the abrasive adheres to the outer surface of the pipe piece while a machining affected layer 7 is formed on the outer surface. Accordingly, due to degreasing with the use of an interfacial active agent, the residue of the buff is removed from the outer surface of the pipe piece, and is subjected to caustic cleaning after water washing to remove the machining affected layer so that the outer surface is smoothened. Then after water washing, it is subjected successively to neutralization, water-washing and hot water-washing, and finally is naturally dried, or is dried by hot air to complete the pretreatment, thereby it is possible to obtain a cylinder stock 8 excellent in smooth surface.
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