Galvanizing removal
Galvanizing removal
(OP)
I am trying to remove the layer of galvanizing from a bolt by means of heat to acquire a sample of the galvanizing to analyze for chemical composition. Does anybody know if this is possible and what temperature is necessary to achieve this. The galvanizing should be Zn (98-99%) alloyed with Lead, Iron, Cadmium, Aluminum, Copper, and Tin.





RE: Galvanizing removal
Hydrochloric acid will also work and will probably be used in the chemical analysis, but scraping is so much easier and will make the analysis simpler.
RE: Galvanizing removal
There are some standard methods for doing this either NACE or ASTM.
RE: Galvanizing removal
RE: Galvanizing removal
RE: Galvanizing removal
With the availability of microscopic analysis techniques, you'll only need a small sliver of the galvanizing. If you could remove the bolt, it could be analyzed non-destructively using SEM/EDS.
RE: Galvanizing removal
In you case a galvanized bolt taken from a lot of bolts could have the same chemistry as one two or many or none in the lot. There is no traceability on a galvanized fastener. A keg of HDG bolts again could come from one plant or commingled with fasteners from many plants.
To overcome the standardization problem we got 2 plants to make chill bar type samples from each line at several different intervals from initial charge to a dross rake. This was when Pb was still in the mix. By doing it this way we got rid of the Fe problem from sampling by only having to remove a very small sample of Zn from any component.
After Pb was removed from the process we just used a sample of ingot zinc, both virgin and reclaimed.
RE: Galvanizing removal
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Corrosion Prevention & Corrosion Control
RE: Galvanizing removal
For the test, I suggest to use mechanical method to get a sample.