Patent attributes
A forming device of forming a metal pipe having a pipe portion includes a first die and a second die constituting a first cavity portion configured to form the pipe portion and a second cavity portion configured to form a flange portion, a drive mechanism configured to move at least one of the first die and the second die, and a gas supply unit configured to supply a gas into a metal pipe material which is held between the first die and the second die and is heated, in which each of the first die and the second die has flange forming surfaces which face each other and constitute the second cavity portion, and a protrusion portion, which protrudes from one flange forming surface to the other flange forming surface, is formed on at least one of the flange forming surfaces of the first die and the second die.