Virginia Galvanizing Corporation - FAQ

1) How does Hot Dipped Galvanized Steel compare to Paint?

2) How does the cost of hot-dip galvanizing compare to other corrosion protection systems, such as paints?

3) How long can I expect my galvanized steel project to last in service?

4) What are the specifications governing hot-dip galvanized steel?

5) How long will hot-dip galvanizing protect my steel from corrosion?

6) Are there any special design and fabrication considerations required to make steel ready for hot-dip galvanizing?

1) How does Hot Dipped Galvanized Steel compare to Paint?

Hot Dipped Galvanized Steel VS Paint

No Special Handling Paper interleve, cloth slings, wood separators

No Field Touch Up Required

Factory Application Field or Factory

No Weather Dependant Yes

-75°F to 392°F Temperature Range < 200°F

Cathodic & Barrier Corrosion Protection Barrier

> 3.9 mils (1/4” thick steel) Coating Thickness Variable

3600 psi Bond Strength 300-600 psi

179 to 250 DPN Hardness/Abrasion Resistance Varies by Type

75 Years Service Life - Atmospheric 12-15 Years Years

2) How does the cost of hot-dip galvanizing compare to other corrosion protection systems, such as paints?

When compared with paint systems, hot-dip galvanizing after fabrication has comparable initial application costs and, almost always, lower life-cycle costs. In fact, the lower life-cycle costs of a hot-dip galvanized project make galvanizing the smart choice for today and tomorrow.

3) How long can I expect my galvanized steel project to last in service?

Hot-dip galvanized steel resists corrosion in numerous environments extremely well. It is not uncommon for galvanized steel to last more than 70 years under certain conditions. To get a good idea of how long your project will last, see the service-life chart.

4) What are the specifications governing hot-dip galvanized steel?

Structural steel (plate, wide-flange beams, angles, channels, pipe, tubing) are galvanized to ASTM A 123/A 123M. Fasteners and small parts that fit into a centrifuging basket are galvanized to ASTM A 153/A 153M. Reinforcing steel is galvanized to ASTM A 767/A 767M.

5) How long will hot-dip galvanizing protect my steel from corrosion?

The corrosion rate of zinc and how long it will provide protection is a function of the coating thickness and the amount of corrosive elements in the atmosphere. For example, in rural settings where there is less automotive/truck exhaust and plant emissions, galvanized steel can easily last for 100 - 150 years without maintenance. Industrial and marine locations contain significantly more aggressive corrosion elements such as chlorides and sulfides and galvanized steel may last for 50 - 100 years in those cases. The relationship between coating thickness and atmospheric conditions is contained in a popular graph developed by the AGA.

6) Are there any special design and fabrication considerations required to make steel ready for hot-dip galvanizing?

Yes. Specifically, fabricated steel must allow for easy flow of the cleaning chemicals and molten zinc metal over and through it. This means that gussets must be cropped, holes put in the proper location for draining and venting of zinc from tubular configurations, weld flux removed, overlapping surfaces must be seal-welded, and light gauge material temporarily braced.

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