how can i distingush????? 6

[vnistra800]

hi friends :

how can i distinguish between material which is plated by another materials and material which is 100% base metal ??

for example :
carbon steel 100%
and carbon steel plated by zinc to get (galvanized steel)???

because i confuse when i want get identification procedure for given sheet??

any articles or links will be gratefull

i am sory for my bad language

best regrds

 

[swall]

The classic test for determining if carbon steel is plated is to put a drop of copper sulfate solution on it. If copper plates out on the steel, the steel is uncoated. You could also put some salt water solution on the sheet and leave it for about 30 minutes. If you see rust, it is not plated.

 

[CoryPad]

Here is a simple and accurate gauge for detecting coatings on metals:

http://www.defelsko.com/pt6kFR.html

Regards,

Cory

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[EdStainless]

Are you concerned about coating other than Zn on steel? (Cu on steel, Ni on Cu and so on)
This can be simple of complicated depending on how many different things you are looking for.

= = = = = = = = = = = = = = = = = = = =
Rust never sleeps
Neither should your protection

http://www.trent-tube.com/contact/Tech_Assist.cfm

 

[vnistra800]

hi friends :

thank u very much for your assisstant.
mr. swall if the material is another carbon steel what test i must do ??
what is concentration of copper sulfate???

thank u very much mr.cory pad for your link

any articles describe the method of identify if the piece is coated or not will be appressiate...

best regrds

 

[kenvlach]

With lots of metal to sort & lots of money available, use X-ray fluorescence (XRF). XRF is ideal for quick, quantitative analysis of most alloys (except for light elements like Be, C, Li, N & sometimes Na, Al, Mg). With good software, one can even analyze composition & thickness of multilayer platings. Handheld units are available. But, most instruments cost $10K-$50K. And, those using a radioactive X-ray source require a government license, although most use x-ray tube sources.

There are a number of books dealing with metal identification, but most are expensive. Vogel's Qualitative Inorganic Analysis is good for chemist types. A, small, out-of-print book: Rapid Identification (Spot Testing) of Some Metals and Alloys, 46 pages, International Nickel Company (1952) is good, and I recall a section in a Metals Handbook, maybe vol.1 of the 8th edition(?), dealing with metals & alloys identification.

There are a number of specific ASTM tests ($), e.g., for detecting hexavalent chromium on aluminum and galvanized steel.

The small, cheap, pencil-sized magnetic thickness testers are very convenient for measuring paint, zinc & other non-magnetic coatings on steels. Sometimes available on eBay for as little as $10.

http://www.defelsko.com/ppenFR.html

For inexpensive ways to identify metals -- color, density, magnetic properties, spark tests, acid tests, wet chemistry, etc., the following is very thorough and a free download. Chapter 4 covers the identification part.
DoD 4160.21-H Defense Scrap Yard Handbook

CHAPTER 4 - SEGREGATION AND IDENTIFICATION 84
C4.1. SEGRATION [sic] AT THE SOURCE 84
C4.2. IDENTIFICATION OF METALLIC SCRAP 85
C4.3. SIMPLIFIED METAL TESTING AND SORTING PROCEDURES 89
C4.4. PROCEDURE FOR CHART 1 102
C4.5. PROCEDURE FOR CHART 2 103
C4.6. PROCEDURE FOR CHART 3 105
C4.7. PROCEDURE FOR CHART 4 107
C4.8. PROCEDURE FOR CHARTS 5A THROUGH 5G 116
C4.9. LABORATORY ANALYSIS OF METALLIC SCRAP 130

http://www.dtic.mil/whs/directives/corres/pdf/416021h_0685/p416021h.pdf

Zinc. A drop of hydrochloric acid foams very vigorously on zinc & zinc plating unless some sort of clear organic sealer or oil has been applied (galvanized sheet is sometimes supplied with a protective oil on the surface).

Copper sulfate test. This is usually used to test for residual iron on the surface of passivated stainless steel. It isn't specific for iron; the copper ions will plate out in an exchange reaction with any less noble (more anodic on galvanic scale) metalexcept those sufficiently passivate to resist the acidic solution.

The test solution is prepared by dissolving 4 g of copper sulfate pentahydrate (CuSO₄·5H₂O) in 250 mL of distilled water to which 1 mL of sulfuric acid (H₂SO₄, sp gr 1.84) has been added.
A drop of solution on bare carbon & most steels (non-stainless) turns reddish-copper color in a few seconds. Take care to first clean or degrease the surface.

 

[kenvlach]

Probably the leading company in portable XRF analyzers, gives lots of info on operating principls & uses. (Thermo Electron bought Niton which had bought Texas Nuclear, if memory serves)

http://www.niton.com/technology.asp

A US Dept. of Energy document on using a portable XRF analyzer to identify metals & alloys in a decommissioned nuclear facility. Gives a lot of acttual use details:

http://apps.em.doe.gov/ost/pubs/itsrs/itsr2397.pdf

Worldwide listing of metal analyzers:

http://www.instruments.ru/manufacturers-suppliers/metal-analyzers.htm

Back to low tech. If you want to try the acid spot tests for metals and don't already have a lab with the various acids, the cheapest route may be an Alloy Metal Detector Kit :

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=190011687999&ssPageName=ADME:B:SS:US:1