6279 105-114, Belmondo, Welding The practice of joining metallic parts by fusion welding is widely used in space industry. In particular this happens in connection with the manufacturing of large Aluminum alloy structures including manned modules and fuel tanks. Up to the last decade, Tungsten Inert Gas (TIG) welding had been the leading technology since the beginning of the space experiments. At the beginning of 1980's Alenia Spazio developed and qualified a TIG welding process to be used for 4 and 7 mm thick aluminum alloy joints designed for SPACELAB modules fabrication. Continuous optimization efforts were made during 1980's in order to furtherly improve the process reliability and the joints quality by reducing the repairing interventions as much as possible. An improved TIG process double pass was qualified and used early in the 1990's in connection with SPACEHAB modules manufacturing. SPACEHAB was the first world commercial space program involving a series of D shaped modules, the last of which still is under production. Nevertheless, in the field of Aluminum alloy weldments, potential problems still exist, mainly in terms of bead geometry, penetration regularity and internal defectology associated to Aluminum oxides presence. For this reasons a new welding technology named Variable Polarity Plasma Arc (VPPA) has been developed at NASA and has became ready for industrial applications in the early 1990's. The main feature of the VPPA process applied in keyholing mode, is its ability to eliminate oxides and associated impurities by a cathodic cleaning action and by improving the penetration capabilities and arc stability. This results in a very high quality welds and hence in a reduction of repair cycles. Alenia Spazio has developed and qualified a Plasma keyhole VPPA process for Aluminum alloy 2219 operating in the range of 3 up to 12 mm joint thickness. VPPA keyhole process is currently used for the fabrication of the Mini Pressurized Logistic Module (MPLM), Nodes 2 and 3 of the International Space Station (IIS) as well as for the European Pressurized Module (Columbus). In the last years a new joining process named Friction Stir Welding (FSW) has been developed and patented by The Welding Institute (TWI). Alenia Spazio acquired the licence to apply the FSW process to future space programs. A technological development plan is in progress in order to qualify the FSW process for Aluminum-Litium 2195 alloy to be used for the Crew Reentry Vehicle (CRV) for which manufacturing activities are expected to start soon.


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    Title :

    Welding technologies for large space structures


    Additional title:

    Schweißtechnologien für die Fertigung großer Raumfahrtstrukturen


    Contributors:


    Publication date :

    2000


    Size :

    11 Seiten, 18 Bilder, 11 Quellen




    Type of media :

    Conference paper


    Type of material :

    Print


    Language :

    English




    Welding technologies for large space structures

    Belmondo, A. / Deutscher Verband fur Schwei≬en und Verwandte Verfahren / Bundesverband der Deutschen Luft- und Raumfahrtindustrie | British Library Conference Proceedings | 2000


    Welding in space and related technologies

    Paton, B. E. / Lapčinskij, V. F. | TIBKAT | 1997


    Enabling Technologies for Active Vibration Control of Large Space Structures

    Preumont, A. / Loix, N. / European Space Agency | British Library Conference Proceedings | 2002


    Space: technologies, materials, structures

    Paton, Borys Jevhenovyč | TIBKAT | 2003


    TIG-welding of space structures

    Klett, H. / Deutscher Verband fur Schwei≬en und Verwandte Verfahren / Bundesverband der Deutschen Luft- und Raumfahrtindustrie | British Library Conference Proceedings | 2000