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Galvanized Steel
Steel coated with a thin layer of zinc to provide corrosion
resistance in underbody auto parts, garbage cans, storage
tanks, or fencing wire. Sheet steel normally must be cold-rolled
prior to the galvanizing stage.
HOT-DIPPED. Steel is run through
a molten zinc coating bath, followed by an air stream "wipe"
that controls the thickness of the zinc finish.
ELECTROGALVANIZED. Zinc plating
process whereby the molecules on the positively charged zinc
anode attach to the negatively charged sheet steel. The thickness
of the zinc coating is readily controlled. By increasing the
electric charge or slowing the speed of the steel through
the plating area, the coating will thicken.
DIFFERENCES. Electrogalvanizing
equipment is more expensive to build and to operate than hot
dipped, but it gives the steelmaker more precise control over
the weight of the zinc coating. The automotive manufacturers,
because they need the superior welding, forming and painting
ability of electrogalvanized steel, purchase 90% of all tonnage
produced.
Galvalume®
Steel sheet with a unique coating of 55% aluminum and 45%
zinc that resists corrosion. The coating is applied in a continuous
hot-dipped process, which improves the steel's weather resistance.
Galvalume® is a trademark of BHP Steel, and the product
is popular in the metal building market.
Galvanized Steel
Steel coated with zinc to provide corrosion resistance for
a wide range of products including automobiles, bridges, storage
tanks, structural steel, fasteners, duct work, light poles,
pipe, sign supports, reinforcing steel and wire.
Gauge
The thickness of sheet steel. Better-quality steel has a consistent
gauge to prevent weak spots or deformation.
Greenfield Steel Mill
New mill that is built "from scratch," presumably on a green
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