EoW November 2013

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News
Corporate
November 2013 10
The dawn of a new age
▲ ▲ The AEOX system from CPA
Co poratenews
Austrian high-quality wire machinery
manufacturer CPA Wire Technologies uses
the gentle but efficient water quenching
system AEOX STS, which helps to save
energy without being harmful to workers
and nature.
AEOX STS is part of the elaborate AEOX
Heat Treatment Technology consisting of
energy-efficient recirculation convection
furnaces for austenitisation and cross-flow
convection furnaces for diffusion, stress
relieving, soft annealing and tempering of
wires and strips. It is claimed that with the
entire AEOX heat treatment technology
users can save up to 40 per cent of energy.
Traditionally, the quenching systems
used in the steel wire industry are lead
baths. In a technical point of view,
these systems are very well suited for
achieving the desired thermal procedure.
But there are major disadvantages which
must not be neglected. First of all, lead
is an environmental poison. Additionally,
residues of lead will always adhere to
the wire which might require additional
chemical cleaning. Finally, heating up and
controlling the temperature of tons of wire
requires valuable energy.
As an alternative to lead baths, fluidised
bed systems have been introduced. These
systems make use of small solid particles
impacting on the wire which extract
heat from the product by direct contact.
Compared to the lead baths, these
systems are environmentally compatible
and have less power consumption. Still,
these systems have some disadvantages.
They are usually operated with sand of 100
to 200μm particle size.
This is a size where dust can enter the
respiratory system and lead to irritations.
Particle sizes below approximately 5μm,
which may be produced during operation,
can even get into the lung and cause
severe health problems. In a technical
point of view, these systems only allow
to run a very narrow dimension range
of wires at the same time, since it is not
possible to adjust the bed corresponding
to the wires individually.
To overcome the described problems,
CPA developed a water-based quenching
system. The quenching fluid is a mixture of
water and organic polymers. These fluids
are environmentally friendly and easy to
handle. Because of the polymer properties,
the vapour film phase at the beginning
of the quenching is very stable. The
comparably long-lasting vapour film phase
results in a controllable quenching process.
The transformation temperature is reached
before the bulk boiling phase starts.
The “AEOX Structural Transformation
System” by CPA (international patent
pending) is designed to run different wire
dimensions at the same time. For that
reason, the cooling section is divided into
individually adjustable sections according
to the customer’s request. The adjustment
is done from outside the tank, without any
manipulation of running wires or in the
quenchant.
The quenching section is directly
connected to the soaking zone, without
leading the wires through surrounding
atmosphere. The soaking zone consists
of two individually adjustable, electrically
heated sections.
In that way it is possible to introduce a
temperature gradient from the entrance
to the exit in order to minimise wire
temperature changes during pearlite
transformation.
The AEOX STS quenching system can
be combined with the energy-efficient
austenitisation furnaces of CPA which
provide energy savings of up to 40 per
cent and an adjustable part load capacity
starting with 30 per cent of the nominal
furnace load.
CPAWire Technologies – Austria
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