| 摘要 |
The subject matter of the invention is a method of forming constructional elements having circular, constant or variable cross-section along the axle and of great slenderness, including cylindrical-tapered and conical pipes, made particularly of aluminium alloys, constructional element obtained in this way and also the device for realization of this mode. In the method, rotating charging pipe - obtained by means of extrusion from the material, of which the creep limit is within 70-100 N/mm 2 and the proportional elongation A is at least 18% - is exposed to plastic deformation in the cold state by means of regulated, circuital pressure of non driven rollers, while: when it comes to charging pipe placed on the rotating mandrel, deformation is carried out such a way, that relative reduction of the diameter of the charging pipe should be not smaller than –¡ d = (d o - d 1 )/d o = 0,03 , and relative reduction of the thickness of the wall of charging pipe should be not smaller than –¡ g = (g o -g 1 ) = 0,1 in order to obtain the creep limit R 0,2 of the material of the produced constructional element within the range 180 - 240 N/mm 2 , and when it comes to rotating charging pipe without the mandrel, deformation is carried out in such a way that relative reduction of the diameter of the charging pipe should be not smaller than –¡ d = (do - d 1 )/d o =0,12, in order to obtain the creep limit R 0,2 of the material of the produced constructional element within the range 180 - 240 N/mm 2 . The invention also discloses a device for carrying out this method as well as an element made by means of this method. |
