Method for forming spool in pipe and manufacturing apparatus for forming spool in pipe

A method for forming a spool, which is a portion protruding outward of a pipe, in a part of a side wall of the pipe, the method comprising:

• clamping the pipe by clamping the side wall of the pipe by a first die comprising at least two members and also clamping the side wall of the pipe by a second die comprising at least two members;
• forming the spool between the first die and the second die by making the first die and the second die approach each other, while pressing an end of the pipe by a third die toward the first die along a longitudinal direction of the pipe;
• separating the third die from the pipe along the longitudinal direction of the pipe such that the second die and the third die separate from each other in a state where the spool is clamped by the first die and the second die;
• and
• unclamping the pipe by releasing clamping of the pipe such that at least one of the at least two members of the first die and at least one of the at least two members of the second die separate from the side wall of the pipe,
• forming a preliminary spool before forming the spool, the preliminary spool being a preliminary configuration of the spool, the forming of the preliminary spool including:
• a pipe expansion process to expand the pipe;
• and
• a pipe contraction process to contract the pipe after the pipe expansion process, and
• the spool being formed based on the preliminary spool.