Cut Sheet

Finishes
B
United States
Tel: [phone]
Fax: [phone]
B2
www.tnb.com
United States
Tel: [phone]
Fax: [phone]
Canada
Tel: [phone]
Fax: [phone]
Technical Services
Tel: [phone]
GoldGalv
®
The standard GoldGalv
®
finish is made up of a multi-step
electrogalvanizing and zinc dichromate process. The trivalent
Chromium finish is applied over the zinc, producing a chemically
bonded non-porous barrier for protection from moisture and air. The
.5 mil electro-plated zinc and gold trivalent Chromium finish provide all
of the features and protection of hexavalent Chromium without the use
of the chemical. (Refer to page A6 for more details)
Green or White Urethane Powder Coated (Suffix GR or WH)
Urethane powder resins are applied electrostatically to the steel
after fabrication. Once the material is completely covered with the
powder-form urethane, it proceeds through a 400˚ baking process
for ten minutes, creating a chemical bond. This results in a minimum
of 1.5 mil thickness of urethane coating providing excellent resistance
to chipping or peeling.
Pregalvanized (Suffix PG)
A zinc coating is applied by hot-dipping the steel coil at the mill
prior to fabrication. Once the material is worked by roll-forming,
cutting, or punching, minimal protection is provided for raw edges.
This weakness is typical with precoated material and affects the
channel section around holes, extreme ends, and the edges of the
“U” shape lips. Superstrut pregalvanized material is in conformance
with ASTM A-525/G-90 specification standards, representing 0.90
ounces of zinc per square foot of steel. This finish is often referred
to as “hot-dipped mill galvanized” or “mill galvanized.”
Hot-Dipped Galvanized (Suffix HDG)
The material is zinc coated after fabrication providing total product
protection on all surfaces. The fabricated channel or fitting is
suspended and then dipped into tanks of hot zinc for a prolonged
period, creating a coherent bond. The result is superior corrosion
resistance as compared to pregalvanized material. Hot-dipped
galvanizing is not recommended for threaded products, considering
the zinc coating thickness will often disrupt the threads. Superstrut
hot-dipped galvanized is in conformance with ASTM Specifications
A-123 (formerly A-386) and A-153. Superstrut channels maintain
a minimum 1.5 ounces of zinc per square foot of steel or 2.5 mils
(ASTM A-123, Thickness Grade 65). This finish is also referred to
as ”hot-dipped galvanized after fabrication.”
SilverGalv
®
(Suffix EG)
Often referred to as “zinc plated” or “electroplated zinc,” the steel
and .5 mils of zinc are bonded by an electrolysis process. This is the
identical process used in the Kindorf Galv-Krom
®
finish without the
numerous benefits of the gold colored trivalent chromium conversion coat
(see Galv-Krom
®
finish for more information). Electrogalvanizing is most
commonly applied to small fittings, hardware and threaded products.
GM17_steelcity_cat_B_1-11 3/23/07 1:07 PM Page B2