Project Title:

Low-Flow, Arc-Head Vacuum Welding

04.08-1933
900058
Low-Flow, Arc-Head Vacuum Welding

Abstract:

On-orbit welding for either assembly or repair of future spacestations and platforms
will require novel approaches to the design of the arc-type welding heads to ensure
that this very successful form of metal joining can be applied in the vacuum of space.
In particular, the clean welds accomplished using the Tungsten Inert Gas (TIG) and
plasma welding approaches make these common and fairly well understood techniques
highly desirable for space application. Although air contamination is not a problem
in space, existing commercially available TIG and plasma welding heads require large
inert gas flow rates (approx. l ;0 liters/min.) for arc stability. This gas consumption
requirement is unacceptable for a practical space-based welding technique. A novel
method of lowering this gas consumption will be developed by using a hollow cathode
in place of a solid Tungsten cathode electrode to reduce the inert gas flow requirement
to approx. 0.02 liters/min. for weld currents of hundreds of amperes.
Low-flow, Arc-Head Vacuum Welding would have application in future NASA and commercial
space-based fabrication. In addition, this vacuum welding concept could be a more
versatile and attractive technique than certain ground-based, electron=beam production
welding systems.
hollow cathode, low-flow, arc-head, vacuum welding