| Abstract: |
The variable influences of gravitation in out-of-position welding exert a strong influence on the balance of forces inside the vapour capillary in out-of-position electron beam welding (EB), and the covering thickness is also not regular. This results in considerable problems and unsatisfactory weld results, especially in the case of joining tasks in the thick-plate range. It is, however, sometimes not possible to avoid out-of-position welding, e.g. because of the size of the part or the weld arrangement, or, in some cases, out-of-position welding has been chosen on purpose in order to have better control of a large molten pool. For a systematic examination of the interactions between the position, the welding parameters and the developing dynamics of the molten pool, comprehensive tests with the electron beam in vacuum (VEB) have been carried out. Based on industrially used materials, a material spectrum comprising austenitic and ferritic steels and also an established 5000 aluminium alloy have been chosen. This, and the plate thickness range of between 2 up to 50 mm allowed the use of a detailed data basis for the optimisation of future manufacturing tasks. Concerning the VEB method, it has been possible to establish that weld formation is systematically dependent on the welding position. It has been demonstrated that, via a defined adjustment of the welding parameters, also thick-plate welds (up to 50 mm) under increasing gravitational influence had been welded with high process stability. Through iterative alterations of the manifold beam manipulation, the tendential possibilities for the increase of the weld quality have, on the one hand, been established; the limits of the method have, on the other hand, been determined and/or extended.
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