Connecting first shaft portion with second shaft portion of shaft of runner of turbomachine, by fixing first shaft portion and second shaft portion, and welding the first and second shaft portions by an electron beam welding method

摘要

The method comprises fixing a first shaft portion (2) and a second shaft portion (3) in such a manner that an axial cavity of the second shaft portion remains accessible from an outside, welding the first and second shaft portions by an electron beam welding method, and cutting/machining a part of the surface of the two shaft portions inside a shaft (1) by a tool, which is introduced to the cavity of the second shaft portion. The first and the second shaft portions are centered when fixing together on a common axis. A closed groove is formed between the first and second shaft portions. The method comprises fixing a first shaft portion (2) and a second shaft portion (3) in such a manner that an axial cavity of the second shaft portion remains accessible from an outside, welding the first and second shaft portions by an electron beam welding method, and cutting/machining a part of the surface of the two shaft portions inside a shaft (1) by a tool, which is introduced to the cavity of the second shaft portion. The first and the second shaft portions are centered when fixing together on a common axis. A closed groove is formed between the first and the second shaft portions during the fixing step. A developed weld is removed during the steps of welding and cutting/machining. The part of the surface and/or a weld seam of the weld are checked by a checking unit. A third shaft portion is connected with a side of the second shaft portion facing the first shaft portion. The second shaft portion comprises a plug receptacle, and the third shaft portion comprises a plugging protrusion for intervening into the plug receptacle of the second shaft portion. The second and third shaft portions comprise a radial first contact surface and a second contact surface. The method further comprises: cutting/machining a part of the second shaft portion facing a front end of the first shaft portion and/or portions of an inner jacket surface of the second shaft portion; plugging the plug receptacle into the plugging protrusion; fixing the second and third shaft portions in such a manner that the first contact surfaces positively lie next to each other; electron beam welding of the second and third shaft portions at the first contact surfaces in such a manner that a dissolution zone of the electron beam weld is formed, where the dissolution zone goes beyond the axle-near end of the first contact surfaces and ends in a material of the second shaft portion. A part of outer jacket surface of the shaft portions of the wave is cutted/machined by a tool, after the electron beam welding step. Electron beam-welded regions of the first and second shaft portions and/or the second and third shaft portions are welded with one another by an arc welding method, after the electron beam welding step. The arc welding method is a metal inert gas method or a metal active gas-welding method. An independent claim is included for a shaft of a runner of a turbomachine.