Difference between Galvanizing and HOT DIP Galvanizing

[bck2ftr]

Dears,

In the current project I am working , I came across the term "Hot dip galvanizing".
Is there any difference between galvanizing and hot dip galvanizing?
Is HOT DIP galvanizing any special process?

 

[CoryPad]

Galvanizing is an imprecise term, especially across multiple languages. In general, galvanizing means hot dip galvanizing.

 

[hokie66]

Agree with CoryPad. To most structural engineers, galvanizing does mean hot dipped. But in its generic form, galvanization can mean any form of zinc coating.

http://en.wikipedia.org/wiki/Galvanization

 

[TomDOT]

The guys who use other methods of applying zinc try REALLY REALLY HARD to be included in the "Galvanizing" definition.

In common use "Galvanizing" most typically refers to hot dip galvanizing. But for a spec writer, you cannot rely on that. You should also be calling out an ASTM.

 

[weldstan]

In addition to the hot dip method, electroplating with or without added melting of the deposited zinc and mechanical galvanizing are done.

 

[hokie66]

Yes, weldstan, but those methods are not equivalent to hot dipped.

 

[MortenA]

No and thats the point, galvanizing (as your link says) includes "hot dip" (or submerged in molten Zink) but it could also be some type of electroplating that may be less efficient. So if you want to be specific put "hot dipped" or if thats not required (or impossible due to the nature of the element that you want to galvernize) write something else... (i think we are in line here )

 

[TomDOT]

For A325 structural bolts, we've been having an ongoing discussion. Mechanically galvanized are easier to get installed properly due to a more homogenous surface, hot dip offers superior corrosion protection.

 

[CoryPad]

It is interesting that the ASTM documents do not use the word galvanizing much.

For example, in ASTM A325: When zinc-coated fasteners are required, the purchaser shall specify the zinc coating process, for example, hot dip, mechanically deposited, Zinc/Aluminum Corrosion Protective Coating, or no preference.

ASTM B695 Specification for Coatings of Zinc Mechanically Deposited on Iron and Steel

ASTM F2329 Specification for Zinc Coating, Hot-Dip, Requirements for Application to Carbon and Alloy Steel Bolts, Screws, Washers, Nuts, and Special Threaded Fasteners

ASTM F1136 Specification for Zinc/Aluminum Corrosion Protective Coatings for Fasteners

 

[racookpe1978]

You mean a Home Depot spray can of galvanizing paint squirted over the bare metal around a new weld ain't equal to a "hot dipped galvanized" coating ? 8<)