Process for forming tubular member

摘要

A process for forming a tubular member is provided which includes a preforming process for tube-expanding (bulge) forming and bending forming a tubular material (Pa) using first and second molds (M1, M2) and a final forming process for crush forming a preformed tube (Pc) using a third mold (M3) so as to give its cross section a desired shape, the preforming being carried out using the first and second molds (M1, M2) heated at temperatures equal to or higher than the recrystallization temperature of the tubular material and the final forming being carried out using the third mold (M3) heated at temperatures equal to or lower than the recrystallization temperature of the tubular material. The process enables a tubular material of aluminium alloy to be formed into a tubular member of high precision and high quality which has expanded portions as well as bent portions and whose cross section varies across its length. The process also enables drastic increase in productivity.