METHOD FOR FORMING AXIALLY SYMMETRICAL PARTS OF TUBE BLANKS Russian patent published in 2008 - IPC B21D22/10 B21C37/16 

FIELD: machine engineering, namely methods for forming tubes with diameters varying in axial direction.

SUBSTANCE: method comprises steps of applying filler pressure to inner surface of tube blank for further axial compression of it at simultaneously inner pressure applying. Pressure applied before axial compression is determined according to given relation q = k[(2.153L² - 2.149 x 10³L + 590.28)T² + (129.784L² - 92.906L +17.518)T + (-1.061L² + 0.785L - 0.139)] where k - shear yield limit of tube blank material, MPa; T = t/rm, L =h/rm, t - wall thickness of tube blank, mm; r m - radius of mean surface of tube blank, mm; h - height of plastic zone, mm.

EFFECT: improved quality of axially symmetrical parts due to elimination of wrinkle formation and ruptures of those parts at forming them of tube blanks.

1 dwg, 1 ex