HYDROFORMING, HYDROFORMING METHOD OF THE FORMING AND VEHICLE MEMBER USING HYDROFORMING

摘要

PROBLEM TO BE SOLVED: To provide a hydroformed product for improving the quality of a forming having an external section gradually and variously changing its outer diameter. SOLUTION: The hydroformed part is obtained by a method that a tube stock 18, which is roughly conical shape obtained by rolling a steel plate member 18a of roughly trapezoidal shape to trace an external shape change of a product, is subjected to hydroforming. Thus, in the case of the product 14 to have the external section changing gradually and variously its external diameter, the high quality product 14 with a tube expanding rate falling in a restricted range is obtained.