Spinning method for forming pipe end
AssigneeNisshin Steel Co., Ltd.
InventorsAkihiro Ando, Kazushi Sakamoto, Shinobu Karino, Kenji Hara
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Abstract
When the necked portion is formed at the end of the pipe material by the spinning method, working rollers are restricted so as to return immediately before the pipe end instead of being allowed to axially move beyond the end of the working object pipe. The diameter reduction amount of the pipe end is set smaller than that of the most diameter reduced portion connecting to the pipe end. A protruding portion of so-called bellmouth shape is formed at the working end, thereby preventing generation of fractures originated from the working end of the base portion or the welded portion and generation of wrinkles during the spinning.
Claims1
A spinning method, which uses a working object pipe and working rollers disposed on the outer surface of the working object pipe and relatively revolved around the working object pipe, wherein, when the working rollers are axially reciprocated while being moved in a radius direction of the working object pipe, to thereby form a tapered portion gradually reduced in diameter toward the end of the working object pipe and, as needed, a straight pipe portion of small diameter which continues thereto, the working rollers are restricted to return immediately before the working rollers reach the pipe end during the axial reciprocation thereof so that a protruding portion is formed at the end of the working object pipe.
Dependencies are inferred from the claim text.