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48 Wire & Cable ASIA – May/June 2016
Feature Furnaces & heat treatments
2015 was an exciting time for the Plasmait team. The
company sold a range of plasma heat and surface treatment
machines in the ferrous and non-ferrous markets. Plasma
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. Deployments
included annealing lines for large and intermediate stainless
steel wire boasting a single line output of 170kg/h and more
for martensitic stainless steels.
Stainless steel wires from 1 to 10mm can now be produced
scratch-free and pile-free at high speed. Superior surface
and homogeneous recrystallisation with small grain
improves subsequent drawing and reduces the number of
wire breaks on the drawing machine.
The new fine wire annealing line allows recrystallisation
annealing at up to 25m/s 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.
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.
The PlasmaAnnealer can cold start production in a few
minutes and can be stopped immediately. This avoids long
heating-up and cooling-down times and associated energy
costs that are symptomatic of a conventional tube furnace.
The first plasma annealer for taped copper conductors has
been in operation for more than a decade. The latest one
was installed in 2015.
The shortcomings of the traditionally used batch annealing
process can be avoided with continuous plasma annealing
and cleaning used in front of the taping line.
Round or rectangular conductors can be plasma annealed
and cleaned in-line with a conventional taping line. Plasma
annealed conductors feature better accuracy in mechanical
properties and better surface finish, which results in superior
tape adhesion.
Plasma heat and surface treatment can be effectively
deployed for plating applications. Plasma-treated copper
or aluminium wires can be hot-dip coated or electroplated
without the need for chemical cleaning or fluxing. For
example, PV ribbon can be annealed to a super-soft state
and tinned without the need for chemicals.
Plasma surface activation can also improve lubricant pickup
in a drawing line. Plasma surface treatment ensures good
lubricant adhesion during the 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 was also 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.
With plasma heat treatment, the individual wires can be
annealed or stress relieved to equal temper/softness.
Plasmait GmbH – Austria
Website:
Versatile heat and surface
treatment process
❍ Last year was an exciting time for the team at Plasmait