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| Abstract No.: |
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Scheduled at:
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Wednesday, March 28, 2012, SuperC, Hall Ford 10:15 AM
Materials 1
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| Title: |
Use of the multiple-focus technology for an influence on weld seam geometry and hot cracking of nickel-based superalloys
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| Authors: |
Christian Börner* / Institut für Füge- und Schweißtechnik, TU Braunschweig, Deutschland
Helge Pries / Institute of Joining and Welding, TU Braunschweig, Germany
Klaus Dilger/ Institute of Joining and Welding, TU Braunschweig, Germany
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| Abstract: |
Presently, a publicly funded research project is carried out at the Institute of Joining and Welding in Braunschweig, as regards the multiple-focus technology in electron beam welding. In this project, fundamental knowledge as regards the influence of the weld seam geometry and the hot cracking, mainly with nickel-based superalloys, is acquired by means of this modern technology. As test material, the precipitation-hardening nickel-based alloy NiCr25FeAlY (2.4633, Alloy 602 CA) was used. The application of the multiple-focus technology, i.e. several foci aligned in the direction of the beam spread in the same melt pool, influences the melt pool dynamics and thus the mixing of the melt. The objective of the investigations is the optimisation of the welding behaviour of nickel-based alloys sensitive to hot cracks so that the crack susceptibility is minimised and they can be joined reliably.
It was shown that nearly every seam geometry can be adjusted by adapting the various process parameters in EB welding and, in particular, the multiple-focus technology. The seam geometry has a decisive influence on the formation of the hot cracks. This is noticeable insofar as the cracks always occur in certain areas. By specifically adjusting the seam geometry, the objective of reliable welding without the occurrence of hot cracks can be achieved.
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