Method for producing a bumper reinforcement

A method for producing a bumper reinforcement, comprising the steps of:

• providing a straight tubular member having a substantially rectangular cross sectional shape,
• forming a curved bumper reinforcement obtained continuously by curving the straight tubular member while being sandwiched between an inner die and an outer die;
• wherein the inner die and outer die have corner portions with;
• corner portions of the inner die located on the side of a back face of the straight tubular member having a radius established in a range of three to ten times as large as a wall thickness of the straight tubular member,
• corner portions of the outer die located corresponding individually to the corner portions of the inner die having a radius established less than the radius of the corn portions of the inner die, thereby forming relief spaces individually between the inner die and the outer die;
• and
• forming angle portions of the straight tubular member between an upper face and the back face and between a lower face and the back face having a radius profiling to the corner portions of the inner die, and
• bulging the angle portions of the straight tubular member into the relief spaces in a range thereof while being curved thereby preventing generation of wrinkles on the angle portions of the straight tubular member.