KnowledgeBase » Top Rated Questions

Is it safe for food to be in contact with galvanized steel?

For most foods, contact with galvanized steel is perfectly safe. Only acidic foods should not come in contact with galvanized steel according the the U.S. Food & Drug Administration. The acid in some foods reacts with the zinc coating to form salts that are readily absorbed by the body and in excess could cause a very mild sickness. So, where is galvanized steel used ...
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How does galvanized steel perform in seawater splash zones?

Splash zones are the most aggressive environment for hot-dip galvanized steel (or any other protective coating) because as the zinc coating reacts with the chlorides when wetted, zinc corrosion products are formed. Then those corrosion products dry and are later washed away when the steel is wetted again at which time more zinc corrosion products form. That process repeats its...
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Measuring Zinc Coating Thickness of Hot-dip Galvanized Steel

Coating thickness is tested by using a magnetic thickness gauge. There are three types of magnetic thickness gauges: pencil-style, banana-style, and electronic. Electronic thickness gauges are the most common and the most accurate. Information on how to measure the thickness with magnetic gauges is contained in ASTM E376, and the minimum coatin...
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What does the cold galvanizing process consist of?

The term “cold galvanizing” is more of a marketing term than an actual process. Cold galvanizing is simply painting a piece of steel with zinc-rich paint. There are not tanks or preparation necessary other than the equipment you would need to paint any other material (blasting tools, spray guns or rollers, etc.). Because the coating is simply zinc-rich paint, it will ...
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Preparing the hot-dip galvanized steel surface for painting or powder coating

Similar to painting over black steel, surface preparation is critical when painting or powder coating over the zinc coating of hot-dip galvanized steel. However, before any surface preparation takes place, the galvanizer should be notified the steel will be painted. With this understanding, the galvanizer will forego any post-treatments that could ...
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Bare Spots

Bare spots, uncoated areas on the steel surface, can occur because of inadequate surface preparation. Bare spots may be caused by welding slag, sand embedded in castings, excess aluminum in the galvanizing kettle, or lifting devices that prevent coating formation in a small area. To avoid bare spots, (left) the galvanizer must ensure surfaces are cle...
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Hot-Dip Galvanized Steel in Water Applications

The varieties of water throughout the world differ to the extent that predicting corrosion rates is very difficult for all coatings. Many parameters affect corrosion of metals in a water environment , including pH level, oxygen content, water temperature, water climate and tide conditions, to name a few. Despite the difficulty of
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What are the differences between ASTM A123/A123M and ASTM A385?

ASTM A123/A123M give the requirements for inspecting the final hot-dip galvanized product, including coating thicknesses and sampling requirements. ASTM A385 gives information on recommended steel chemistry for steel to be galvanized, as well as required venting/drainage hole requirements. You can think of A385 for use prior to hot-dip galvanizing while A123 is used after hot-dip galvanizing. There are some requirements in
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How to Clean Wet Storage Stain

Treatment of wet storage stain begins with drying the galvanized surface. As long as water remains on the zinc surface, and airflow is limited, the corrosion mechanism responsible for wet storage stain will continue, and can damage the zinc coating and underlying steel. After the galvanized surfaces are dried, the treatment processes differ dependi...
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Reasons for Duplex Coating

There are seven good reasons to paint or powder coat hot-dip galvanized steel: Extended Durability – in what is called the synergistic effect between galvanized steel and paint, the zinc of the galvanized coating is a barrier protection to the substrate steel, cathodically protects it, and provides underfilm corro...
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