Pipe forming apparatus and method

摘要

A method of cold forming a tulip end in steel pipe including the steps of: providing a pipe-expanding die assembly including a circumferential array of die segments each being mounted on a base for radial movement from a closed up position allowing the array to pass into the open end of the pipe, each segment having an axial camming surface facing towards the axis of the array and adapted to cooperate with a corresponding surface on an axially movable wedging body operable by hydraulically drawing it through the array to spread the segments, the die segments each having a part annular die portion forming the shoulder of the tulip shape and a part conical die surface forming the bell of the tulip shape; moving the segments to the first position; passing the pipe end over the array; operating the wedging body hydraulically to spread the segments and expand the pipe end to partially conform to the die surfaces; and operating the wedging body to allow the segments to move toward the closed up position to release the pipe end.