METHOD FOR MANUFACTURING EXTRUDED HOLLOW PIPE, AND HOLLOW PIPE

摘要

PROBLEM TO BE SOLVED: To provide a method for manufacturing an extruded hollow pipe which ensures the highly precise straight extrusion of the pipe without hollow diameter deformation, and the hollow pipe obtained by this method. SOLUTION: When the hollow pipe is manufactured by drawing a rotary shaft after a hydraulic composition is extrusion-molded concentrically around the rotary shaft and cured, the degree of thermal shrinkage of the rotary shaft during a curing process is higher than the hydraulic composition and a gap is formed between a pipe body made of the hydraulic composition and the rotary shaft in the curing process. In addition, the content of hydraulic powder of the hydraulic composition is preferably 20 to 35 wt%. COPYRIGHT: (C)2004,JPO