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Cooperative Research Centres Association Media Release
04/09
February 24, 2004
AUSSIE WELDING TECHNOLOGY TAKES OFF GLOBALLY
An Australian welding technology that promises to revolutionise
the metal fabrication industry, saving millions of dollars, is
taking off worldwide.
Licences for the Australian-invented Keyhole TIG welding technique
have been granted to two of the largest stainless steel pipe producers
in the United States and Europe, with strong interest from other
European, North American and Asian companies.
Keyhole TIG welding, developed by scientists in the Cooperative
Research Centre for Welded Structures and CSIRO in Adelaide, is
proving significantly faster, cheaper and simpler than current
welding methods for corrosion-resistant metals like stainless
steel, nickel alloys and titanium.
The technique forms a "keyhole" right through the metals
to be joined, liquefying the material evenly so that the join
is stronger and more uniform. The keyhole closes behind the torch
like a zipper as it moves along, explains CSIRO's Dr Ted Summerville.
"Its uses include tube making, welding of rotatable products
such as pipes, and the joining of large sheets. It is particularly
suitable for welding titanium alloys, because it reduces the opportunity
for contamination," he says.
"Until now, the advantages of keyhole welding, with its
deep penetration through the thickness of the material, were only
available using plasma arc, laser or electron beam facilities
- which are high-energy processes, very expensive and rather finicky,"
says Dr Summerville.
"But now that some of these major companies have taken a
close look at the Australian keyhole technique, they've realised
the job can be done much more cheaply and simply, and with better
results. They are really thrilled with it."
The secret of the Australian keyhole welding method lies in an
understanding of the fundamental physics of the welding arc, which
allows a balancing of the surface tension of the molten metal
against gravity, and the gas and arc pressure of the torch.
The new keyhole system is being made available to metal fabrication
firms, large or small. While it draws more current than conventional
gas tungsten arc welding, the process requires no special power
supply, just a new torch and the know-how to use it correctly.
"This new process can be used for welding all types of stainless
steel, mild steel, nickel and titanium alloys, and other exotic
metals", Dr Summerville says.
"This can be carried out in a single pass, instead of the
six or seven passes previously required - which represents a dramatic
gain in productivity. Welding stainless steel and titanium previously
took hours. It can now be automated and completed in minutes."
Another advantage is that the process welds joints with square
edge preparation which reduces both machining costs and the amount
of filler material required to complete a joint. Keyhole TIG of
12 mm stainless steel plate typically requires only about 50 grammes
of costly material per metre of weld, in contrast to a kilo or
so of filler with conventional processes.
Between them these advantages offer huge savings to the metals
fabrication industry.
Licenses for the Australian keyhole welding technology are being
granted in Australia, Europe, the USA and Asia for use in the
manufacture of products ranging from spiral-welded pipe and titanium
sheet to railway rolling stock, says CRC WS Chief Executive Dr
Colin Chipperfield.
"Several licensees in these markets have reported significant
productivity improvements. The Americans in particular are highly
impressed and talking about converting their whole system to using
the Australian technology."
The research addresses the third of the Federal Government's
National Research Priorities - frontier technologies for building
and transforming industries.
More information:
Dr Ted Summerville, CRC Welded Structures & CSIRO 08 8303
9135
Dr Colin Chipperfield, CRC Welded Structures 02 4252 8889
http://www.cmit.csiro.au/innovation/2003-10/keyhole.cfm
CRCA Media: Prof. Julian Cribb 0418 639 245
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