Patent ID: 7464572
Filing Date: 2008-12-16
Classification: B21D,C22F,Y10T

Abstract:
1. A process for forming a tubular member, in which a tubular starting material is formed into a desired shape while applying an internal pressure to the tubular starting material, said process comprising: a step of providing a pre-forming mold having a cavity formed therein and a final forming mold having a cavity formed therein, a pre-forming step of pre-forming said tubular starting material into a preformed tube by setting the tubular starting material into the cavity of the pre-forming mold and clamping the pre-forming mold while applying an internal pressure to the tubular starting material, wherein the tubular starting material has a recrystallization temperature; and a final forming step of final forming the preformed tube into the tubular member having a cross section of a desired shape by setting the preformed tube into the cavity of the final forming mold and clamping the final forming mold while applying a predetermined internal pressure to the preformed tube, wherein the preformed tube has a recrystallization temperature, and wherein a respective temperature of each of the mold is controlled so that the pre-forming mold is kept at a temperature equal to or higher than the recrystallization temperature of the tubular starting material, while the final forming mold is kept at a temperature equal to or lower than the recrystallization temperature of the preformed tube.