How does galvanizing work?
Hot-dip galvanizing is the process of coating iron or steel with a layer of zinc by immersing the metal in a bath of molten zinc. During the process, a bonded coating is formed which protects the steel from harsh environments.
Where is galvanizing used?
Galvanized steel can be used anywhere rust protection is required including metal sculptures, handrails, iron gates, roofing, metal appliances, as well as nuts and bolts to name a few.
How long will galvanized steel last?
Galvanizing is probably the most environmentally friendly process available to prevent corrosion. Data shows that galvanizing can provide between 34 to 170 years of protection for steel.
Can I paint over galvanized steel?
Galvanized steel can be painted and often customers choose to paint their galvanized steel for the following reasons:
To add depth and artistic flair to a project
Provide additional protection in certain environments
Increase the lifespan of a structure.
What metal is used in the galvanizing process?
Zinc - is used throughout the galvanizing process to steel or iron in order to create a protective coating. It is commonly used as a method of protecting metals from corrosion as the layer of zinc prevents the metal from oxidizing.
Who invented galvanizing?
Galvanized steel is all around us and plays a vital role in our everyday lives but did know, records show that galvanizing has been around since 500BC. The famous Indian medical text, Charaka Samhita, written around 500 BC, mentions a metal which when oxidised produced pushpanjan, also known as ‘philosopher’s wool’, thought to be zinc oxide.
What is venting and draining and why does my product need drilling before being galvanized?
For effective galvanizing, cleaning solutions and molten zinc must flow without undue resistance into, over, through, and out of the fabricated article. Failure to provide for this free, unimpeded flow can result in complications for the galvanizer and the customer. Improper drainage design results in poor appearance, bare spots, and excessive build-up of zinc - American Galvanizers Association.
The primary reason for vent and drain holes is to allow air to be evacuated, permitting the object to be completely immersed into cleaning solutions and molten zinc. Proper hole sizing and location make it safer to galvanize and provide the optimal finish. The secondary reason is to prevent damage to the parts - American Galvanizers Association.
It is important to consider that during the galvanizing process, steel is immersed into and withdrawn from a bath of molten zinc reaching 450°C. As a result, any features of the steelwork which aid the access and drainage of molten zinc will improve the quality of the coating.
For any steel product, holes may be present for other design purposes and may fulfil the requirements for venting and draining however in some cases, it may be necessary to provide extra holes for this purpose.
"For complete protection, molten zinc must be able to flow freely to all surfaces of a fabrication. With hollow sections or where there are internal compartments, the galvanizing of the internal surfaces eliminates any danger of hidden corrosion during service." - Galvanizers Association.
How does galvanizing protect metal from corrosion?
Zinc corrodes in preference to steel and sacrifices itself to protect the steel, hence hot-dip galvanizing will provide this sacrificial protection.
The corrosion products from the zinc are deposited on the steel resealing it from the atmosphere and therefore stopping corrosion.