TPT January 2011

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January 2011 61 ›
Technology Update
IN the fabrication of components for nuclear
power plants, safety is the first priority.
Safety is guaranteed by using high quality
materials, complex production processes
and the highest quality standards. In this
industry, as in any other, production costs
are of particular importance.
Polysoude, France, has tailored a
welding solution for a Russian supplier of
pressure-vessels to bring in line the required
productivity and security. The manufacturer
of pressure-vessels has an export ratio of
80 per cent, and attaches great importance
to short delivery schedules.
A joining system was drafted, made
using standard mechanised components,
offering the optimal welding technique, and
the optimal procedure combination for any
wall thickness, for any diameter and for
any material type. The system uses either
the plasma or TIG-welding process, or both
combined. With large diameters there is a
choice to either weld from the outside to the
inside, or vice versa.
An integrated camera allows the visual
control of the welding process. The sections
consist of low-alloyed or austenitic steel.
Their length ranges between 1,000 and
3,000mm, in diameters between 800 and
1,500mm, and wall thicknesses between 5
and 40mm.
For components with butt weld preparation
and wall thicknesses up to 8mm, plasma
welding with cold wire is the right choice.
For greater wall thicknesses, the procedure
combination takes effect: the root is welded
with plasma/cold-wire process, and the
filler and cap pass with the hot-wire TIG
process. Depending on material and material
thickness, welding speeds reach between 60
and 250mm per minute.
Polysoude SAS – France
Fax: +33 2 4068 1188
Email:
Website:
Plasma process: seam welder
for vessel longitudinal seams
Seam welding: TIG, plasma or both?