TPT July 2011

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July 2011 95 ›
Coating, PiCkling & g alvanising
Zinc spraying on tube seam
A ROLL forming machine draws hot or cold
rolled steel through successive stations and
shapes the material into a tube. Electric
resistance welding closes the seam left by
the butted edges. Although no filler metal
is added that would change the chemical
compositions, the welding process applies
temperature high enough to sacrifice some
corrosion resistant properties of the base
metal. The process may also vaporise
aluminium or galvanised coatings previously
applied to the rolled steel.
A contoured scrafing tool or smoothing
mandrel removes welds pattern or excess
material from the outer diameter of the
tube surface. Many tube makers install
a two-wire electric arc spray process
directly down line from the scrafing tool
or smoothing mandrel. The spray process
applies coatings of aluminium, zinc or their
alloy materials to reinstate the corrosion
resistance properties of the tubing. Applying
the spray material while the weld seam is
still hot assures a metallurgical bond of
the substrate, improves both the deposit
efficiency and density of the sprayed
material, and allows the coating to blend,
thereby helping the weld seam.
Arc spray is, in terms of operating
cost, the least expensive of the thermal
or metal spraying processes used for
applying metal coatings to base materials.
Any electrically conductive material in wire
form can be arc sprayed.
The wire pulling system is powered
by an AC motor fitted in the gun, which
ensures precision wire feed speed. The
wires meet at the head of the gun and melt
in the electrical arc, and the molten mass
is atomised and blown on to the substrate
with compressed air. The particles cool to
ambient temperature and coalesce into a
high quality metal coating.
Metallizing Equipment Co Pvt Ltd has
supplied this system to tube mills throughout
the world.
Metallizing Equipment Co Pvt Ltd – India
Fax: +91 291 2746359
Email:
Website:
Flexible UV
coatings
help to build
business
WHEN a US tube manufacturer repeatedly
experienced premature corrosion on pipes,
end-user warranty claims and unanswered
service requests to their coatings supplier,
management realised it needed serious help
from industry experts. They took action and
contacted Quaker Chemical Corporation.
Quaker is a leading global provider of
process chemicals, services and technical
expertise to a wide range of industries. It
offers a complete “front-to-back” product
portfolio for the tube & pipe industry,
including lubricants, coolants, cleaners,
rust preventives and coatings – including
UV coatings.
Quaker used its integrated knowledge
of steel manufacturing, metalworking fluid
processes and coatings chemistry to recom-
mend an appropriate solution that would not
only increase the flexibility of the tube coating,
but also offer superior corrosion protection
and increase the cosmetic appearance of
finished tubes. The resulting elimination of
rejects/returns and improved quality not only
decreased costs, but also opened new sales
opportunities for the manufacturer.
Quaker’s customised QUAKERCOAT®
product is a high-gloss, 100% UV-curable,
permanent protective coating. This product
offers a lower total applied cost, because
the formulation chemistry provides balanced
properties for flexibility, hardness and
corrosion protection. In addition, this eco-
friendly line contains zero-VOC emissions,
has virtually no overspray and very limited
discharge, and is available in different
colours.
By switching toQuaker’sQUAKERCOAT®
UV product, the tube manufacturer was
able to: eliminate the premature corrosion
issues, which resulted in significant cost
savings ($85,000 saved in lost claims and
$25,000 saved in rework over an 8-month
period); receive regular technical service
visits from Quaker, resulting in increased
worker morale because the operations staff
felt taken care of by their management
team; and increase its own market image
and as a result gain new business.
To learn more about Quaker Chemical
and its full product line offerings, including
its UV-curable series of coatings, please visit
quakerchem.com
Quaker Chemical Corporation is a global
provider of process chemicals, chemical
specialities, services, and technical
expertise to a wide range of industries
– including steel, aluminium, automotive,
mining, aerospace, tube and pipe, coatings
and construction materials. Quaker’s
products, technical solutions, and chemical
management services enhance customers’
processes, improve product quality, and
lower costs. Quaker’s headquarters is
located near Philadelphia in Conshohocken,
Pennsylvania.
Quaker – USA
Website:
The Metallizing Equipment machine applies cooatings to
aluminium and zinc or their alloy material