PRODUCTION OF CYLINDER MEMBER HAVING ELEVATIONS ON ITS INNER OR BOTH FACES FROM PIPE WITH OUTER ELEVATION

摘要

PURPOSE:For simple, good-yield production of cylindrical member having elevated portions on its inner and outer surfaces or only inner surface, a pipe having on its outer face an elevated portion is plastically deformed in an oval shape and pressed to contract pipe diameter in the oval major axis direction by use of plurally devided die. CONSTITUTION:Centrifugal cast or build-up welded peripheral elevation T is pressured on the whole of its surface through back plate X, X. This forms the elevation T in a substantial oval shape and nearabout straight pipe S in a slight oval shape. To prevent excessive straight pipe S oval formation, a core metal P is inserted, as required. The minor axis H of the elevation T oval is made smaller than the die internal diameter D'. The oval shaped elevation T and near straight pipe is pressed in the major direction to contract its diameter, by use of a pair of half dies having semicircular faces that will combine to form a circle of the diameter D' of the die. Thus, the method produces pipe having elevated prtions on its inner and outer faces or only on inner faces.