To provide a method for hydroforming a component having a long tube-expanding region in which no buckling nor wrinkle remains, and a long hydroformed component having a large tube-expanding ratio.
A first step of expanding the portion of a metal tube near the end thereof is carried out by boosting the internal pressure in a state where the metal tube is fixed at the opposite end positions thereof or in a state where axial pushing force of 10% or less of the total axial pushing force is applied to the metal tube, and then axially pushing the metal tube while the internal pressure is maintained at a fixed level, followed by a second step of expanding the central portion of the metal tube by boosting only the internal pressure without axial pushing, and a third step of subsequently lowering the internal pressure down to the above fixed level. Then, after repeating the first through third steps once or a plurality of times, the internal pressure is boosted in a state where axial pushing is not performed or axial pushing force of 10% or less of the total axial pushing force is applied, thus obtaining a hydroformed component.
SATO KOICHI
WADA MANABU
KURIYAMA YUKIHISA
Takashi Ishida
Tetsuji Koga
Hiroshi Kamematsu
Nakamura Asayuki
Nagasaka Tomoyasu