EuroWire March 2015

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News
Technology
March 2015 52
Plasma proves itself in a range of
continuous applications from mainstream
stainless steel annealing to precision alloy
wire cleaning and heat-treating.
The past two years have been an exciting
and productive time for the Plasmait
team. The company sold a range of
plasma machines in the ferrous and
non-ferrous markets, and it is proving
its performance in an increasingly wide
range of materials, from mainstream
copper alloy and aluminium wire to
specialist medical tubes and ropes,
jewellery strands, aerospace materials,
electronics and semiconductor wire and
strip.
Most significant is Plasmait’s success in
the stainless steel and nickel alloy wire
and tube markets with new deployments
in fine, medium and large cross-section
materials. Deployments included
annealing of various forms, ie wire, tube,
strip, strand and ropes.
For example, Plasmait’s most recent
annealer for large and intermediate
stainless steel wire boasts a single line
output of 130kg/h (250lb/h). Stainless
steel wires from 1mm-6mm can now be
produced scratch-free and pile-free at
high speed.
Furthermore, superior surface and
homogeneous recrystallisation with small
grain improves subsequent drawing by
reducing the number of wire breaks on the
drawing machine. Die wear is also reduced.
The Plasma annealer can cold start
production in a few minutes and can be
stopped immediately. This avoids the
lengthy heating-up and cooling-down
times and associated energy costs that
are symptomatic of a conventional tube
furnace.
Equally important was the introduction of
a new fine wire annealing line, allowing
recrystallisation annealing at up to 25m/s
(5,000ft/min) on a range of fine stainless
steel and nickel alloy wires. It is now
possible to anneal fine stainless wires
in-line with the drawing machine.
The annealer features compact design,
high-energy conversion efficiency and
low gas consumption. Annealing fine
wire at up to 20 times the speed of a
traditional strand furnace means fewer
take-ups and payoffs and hence lower
cost of total capital investment.
With the introduction of high-output
annealers Plasmait also became
competitive in the mainstream stainless
steel markets in the fine, small and large
diameter ranges. A single line of a high
output plasma annealer can replace five
to 20 annealing lines of a conventional
annealing furnace.
This means a considerably lower
investment in transport and winding
equipment, which often bears the brunt
of the cost of annealing equipment. The
savings are even more pronounced on
fine sizes where a plasma annealer runs
in-line with a drawing machine.
The first plasma annealer for taped
copper conductors has been in operation
now for more than a decade. The latest
one was installed in 2014 with another
one scheduled for delivery in early 2015.
Taped conductors have traditionally been
annealed in bell furnaces, which may
result in uneven recrystallisation and
surface quality issues like sticking of flat
products.
Round or rectangular conductors can
now be plasma annealed and cleaned
continuously in-line with a conventional
taping line.
Plasma annealed conductors feature
better accuracy in mechanical properties.
Better surface finish also results in
superior tape adhesion.
The latest deployment of PlasmaCleaner
features plasma surface activation for
improvement of lubricant pickup in a rod
drawing line. Plasma surface treatment
ensures good lubricant adhesion during
drawing of stainless steel or titanium rods.
Surface activation is achieved at low
temperatures, which makes the process
particularly economical compared to
expensive-to-run traditional processes
such as brushing, acid treatment or sand
blasting.
Among the latest deployments is a
plasma annealer for stranded conductors
and ropes.
The annealer was designed to allow
for rapid heat penetration through the
cross-section of the stranded construction
so that individual wires in a strand/rope
can be heat-treated to an equal temper.
Accurate control of heat transfer and
thereby resulting mechanical properties
can be achieved on a wide range of
stranded constructions and materials
from copper, aluminium, stainless steel
and alloys.
Plasmait GmbH – Austria
Website:
Versatile heat and surface treatment process
▲ ▲ Plasmait is proving its performance in an increasingly wide range of materials
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