METHOD OF MANUFACTURING DOUBLE-LAYER WATER PIPE USING HYDRO FORMING

摘要

PURPOSE: A water pipe manufacturing method using hydro-forming is provided to secure the high combination performance of the pipe using a hydro-forming method which expands an inner and an outer pipe using the fluid pressure. CONSTITUTION: The inner pipe is inserted into a steel outer pipe. The inner pipe is made of an anticorrosive material selected one of stainless steel, and titanium and aluminum. The external diameter of the inner pipe is smaller than the inside diameter of the outer pipe(S210). The both ends of the mold are sealed with the sealing part, and a through-hole of the sealing part is connected to an apparatus for supplying a fluid(S220) after a steel outer pipe is placed in a mold. The inner pipe is sinister-expanded by supplying the fluid and the outer pipe is elastically expanded(S230). The inner and the outer pipe are friction-combined by elastically returning the outer pipe by discharging the fluid from the inner pipe(S240).