Hot-dip galvanizing is a process of applying a protective zinc coating by dipping product in bath of molten zinc. Galvanizing is a favored method of protective coating due to its low cost, ease of application, and long maintenance-free service life. Generally applied at 830 to 870 degrees, the zinc will bond with the steel. It is the most common outdoor protective coating in use. When used on bolts, due to the thickness of the zinc coating, all galvanized nuts must be tapped oversize.
Zinc plating or electroplating is a process where zinc is applied by using a current of electricity. It is a thinner coating than hot-dip galvanizing making it unsuitable for outdoor applications. Its advantages are its brightness and uniform color making it more aesthetically appealing.
The ASTM specification covering hot-dip galvanized fasteners is F2329, while the specification covering zinc plated fasteners is F1941.
Where can I get a swing set hot dipped galvanized again? It is about 60 years old and some places have rust showing. I am in the Houston , Texas area.
@Robert- You would need to call around to some local galvanizers and find out what their largest item dimensions are. Your swing set would be much too large for our tank.
For street light poles please give comparisons that hot dip galvanised poles are better than swedged poles
@Kailas- Hot dip galvanized and swedged anchor bolts are not mutually exclusive – you can have both. Additionally, one doesn’t have anything to do with the other, Swedging helps to increase the bolt’s pull out strength in the concrete, whereas hot dip galvanizing is simply a corrosion protection coating that has nothing to do with the strength of the material.
I noticed that ‘wedge’ type expansion anchors can be supplied with what they call a
“mechanical’ galvanized finish, which actually looks just like ‘hot-dipped’.
What’s the difference? Does it meet the same specs?
@Dan- Mechanical galvanizing is performed per ASTM B695, and is tumbled with zinc dust and glass beads in a liquid medium, so the zinc is cold fused onto the steel. Hot dip galvanizing is just that, dipped into hot molten zinc. Hot dip galvanizing is performed per ASTM A153 or F2329 and is a thicker and longer lasting coating. For wedge anchors mechanical galvanizing is more commonly available, although I believe some manufacturers make hot dip galvanized anchors.
Dear Sir
now i planed to purchase the electroplated Swivel coupler for scaffolding purchase.
But i want to know which is give better life & corrosion resistance ELECTROPLATED or GALVANIZED.
Because out power plant near Sea.
Please
@Rabindra- Hot dip galvanizing is a much thicker coating and will provide a longer service life than electroplating.
Your descriptions above indicate that electroplating is not suitable for outdoor applications. Would that include underwater applications?
@Ramsey- Electroplating is a very thin coating (0.0003 average) that will offer limited corrosion protection regardless of the environment. Hot dip galvanizing is roughly 10 times that thick (approx 0.002 min) and offers more corrosion protection. We cannot make any recommendations for your specific application, but caution should be used with electroplating if corrosion protection is a concern.