A process for forming a hollow member with A complicated cross-section wherein a section of a tube blank first undergoes a bending deformation due to its internal pressure and bend moment generated by the upsetting of an upper die, and is then compressed to be molded under the support of the internal pressure. The process of the invention does not require the reshaping step at an increased pressure. The process can make a hollow member with a complicated cross-section formed under a low pressure, and solves a technical bottleneck relating to a conventional process for forming this kind of members that is subject to an ultrahigh pressure generator.

A process for forming a hollow member with A complicated cross-section wherein a section of a tube blank first undergoes a bending deformation due to its internal pressure and bend moment generated by the upsetting of an upper die, and is then compressed to be molded under the support of the internal pressure. The process of the invention does not require the reshaping step at an increased pressure. The process can make a hollow member with a complicated cross-section formed under a low pressure, and solves a technical bottleneck relating to a conventional process for forming this kind of members that is subject to an ultrahigh pressure generator.

A process for forming a hollow member with A complicated cross-section wherein a section of a tube blank first undergoes a bending deformation due to its internal pressure and bend moment generated by the upsetting of an upper die, and is then compressed to be molded under the support of the internal pressure. The process of the invention does not require the reshaping step at an increased pressure. The process can make a hollow member with a complicated cross-section formed under a low pressure, and solves a technical bottleneck relating to a conventional process for forming this kind of members that is subject to an ultrahigh pressure generator.