Lightweight garage #15 Friction stir welding for Ariane 6

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Lightweight garage, News

The vehicle

In this garage is a vehicle that flies high. Ariane 6 is the next development stage after the Ariane 5 launcher. Like its predecessor, it was also intended to be used to transport various types of satellites. As each kilogram of payload to be transported into orbit already costs over 10,000 dollars, the long-term goal is to reduce launch costs.

Image source: ©SkywalkerPL – Ariane 6CC BY 3.0

The technology

In order to reduce the weight of Ariane 6 in the long term and thus reduce costs, various technologies are being used. One of these technologies is friction stir welding. As the name suggests, the process is a type of welding. However, in contrast to conventional welding processes, the joining zone is heated less and a much smaller welding influence zone is created, which has a positive effect on the mechanical properties. This is also reflected in the same material characteristics of the material and the weld-affected zone. In addition, materials and material combinations can be welded that are otherwise not weldable. These advantages are used to manufacture the hydrogen tanks for the Ariane 6 rocket. By switching from TIG welding to friction stir welding, the set-up time of more than three hours can also be significantly reduced. In addition, friction stir welding does not require any filler materials for welding, which eliminates another cost factor.

The lightweight aspect

As already explained, the aim here is to reduce costs. In addition, the measures achieve a reduction in weight, which also has a positive effect on cost development. Friction stir welding has already demonstrated similar results in various applications. For example, the technology has already been used in vehicles such as the Ford GT (2004) and Mercedes SL (2012). Friction stir welding is particularly advantageous for thin sheets, as the sheet thickness does not have to be increased, unlike with conventional processes. Due to the better mechanical properties compared to other welding technologies, the weak point "weld seam" can be assessed differently and thus the component weight can be reduced.

Image source: ©MT Aerospace AG, Friction stir welded hydrogen tank of Ariane 6

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