| 摘要 |
An apparatus for bending a pipe about a fixed forming member serving as abutment has members gripping the pipe externally as well as two mandrels intended to come inside the pipe. Each mandrel has an end piece movably carried by one end, the end pieces being against each other inside the pipe at the beginning of bending. During the initial bending phase, each end piece is urged outwards from the bending center to expand the pipe to such an extent that after terminating bending, the pipe is given a circular cross section subsequent to a certain amount of return spring of the pipe wall.
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