Very strange question for the experts: 1

[v20102]

Hello all,

Thank you in advance for any information.

I have a strange question and found this forum, so I am hoping that you can help me.
I work with museums and collectors in the US and Europe in the authentication of military and other artifacts (swords, helmets, etc.).

We have an issue with items made of steel and other metallic materials.
The issue is this: many museums, collectors, etc. are looking for a way to authenticate artifacts based on their metallic composition. This is because of a large number of post-1945 reproductions flooding the market.

For many of these items (European swords for example) we know the source of the steel (Solingen Germany).

Would it be possible to use (or develop) a non-distructive test that could be used on artifacts "in question" to compare their metallic composition to that of known period Solingen steel?
I.E. a "fingerprint" of the steel composition.

If not, is there some other way to make this determination? (assuming that the same forging methods were used in both pre and post 1945 periods)?

Anything at all would be helpful!

Thank you in advance!
John

 

[cloa]

The recycled steel is totally mixed with the virgin steel so the iron's radiographic fingerprint would change- the steel of 50 years ago would be all virgin so you could trace it back to the ore deposit that originated from.

 

[EdStainless]

Actually you can get S and P with the new handhelds.
And while these units are not as accurate as fixed lab equipment, but give me a controlled environment and a few hours and I can get precisions that are very close.
There are units now that use either vacuum or He path to further enhance the light element sensitivity.
Here are some examples.

http://www.bruker-axs.com/traceriiiv.html

http://www.niton.com/art-and-archaeometry/applications.aspx?sflang=en

http://www.olympus-ims.com/en/innovx-xrf-xrd/archaemetry/

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Plymouth Tube

 

[mrfailure]

Thanks, EdStainless for the update. I also understand I may have been wrong regarding getting carbon, at least with the newer units.

Aaron Tanzer

http://www.lehightesting.com

 

[EdStainless]

They might do C in cast irons, but not steels.

I saw a guy using a handheld with He purge and a program that changed x-ray tube voltages for various elements. It was lightyears ahead of units that I had worked with.

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Plymouth Tube

 

[moltenmetal]

I'm betting on the native trace radioactivity of the items being able to tell the tale. A very sensitive radiometer should be able to tell a piece of modern steel from a piece of pre-1945 steel, not based on the C13 content (which would need to be controlled for) but on the content of other emitting atoms present at trace levels in the post-nuclear era steels. If the counterfeiter has gone to the effort of making their own steel from pieces of pre-1945 scrap, they'll sneak by- but you'd catch most of them.

 

[deadrange]

I would also like to remind everyone that the analysis of tramp elements would be very good for this determination. EAF's have only been around for a relatively short amount of time. Copper content should be relatively low in most older steels as they were likely produced through virgin iron. Granted some grades may actually contain copper but it may help in your analysis.

My experience with X-ray spetro guns is that they have a limited window of operation. It for instance has a very difficult time detecting the difference between 4130 and 4140 material. Granted in this case the only difference is a light element Carbon which it cannot determine and Mn which depending on the heat may only have a 0.10 spread between the two materials.

I think the most tried and true methods would involve some sort of destructive test which I know you don't want to do.

 

[v20102]

Hello all,

Thank you so much for your incredible and informed input.
It is always good to "speak" with those "in the know".

It sounds like this is going to be a little more complex (and costly in reference to the quotes that I have received for this equipment) than I initially anticipated.
It also appears that without testing, we may not know if this is a viable application for this technology.

I will take the advice of Metengr and others and try to locate a lab in my area which may be able to conduct some initial tests to determine whether there is a reliably measurable difference in the steel composition.

I am actually also getting more excited about the trace radioactivity test. This sounded a little "far out" when I heard about it initially, but if true, this may be a much more simple method of "dating" pieces. Again, since essentially all of the high quality reproductions are recent creations, making a simple "pre/post 1945" determination would absolutely solve our problems.

Now, I am off to research devices to measure trace radioactivity.

Any suggestions (needs to be portable)?

Thank you so very much for the help!

John

 

[arunmrao]

"Metal provenancing using isotopes and the Oxford Archaeological lead isotope database (OXALID)

http://www.scribd.com/doc/74132318/...d-archaeological-lead-isotope-database-OXALID

In India the Department of Atomic Energy,has a separate wing which assists archaeologists in dating and classification,perhaps close on the lines of work that you are looking for.Hope it helps.

_____________________________________
"It's better to die standing than live your whole life on the knees" by Peter Mayle in his book A Good Year

 

[v20102]

Hello all.

Thank you again for all of the tremendous input.

It looks like both the alloy analyzers and radioactivity test could (at least in theory) meet our needs.
Unfortunately however the type of equipment required is preventative (cost in the case of the analyzers, and mobility in the case of the radioactivity tests).

Before plodding ahead in these directions, I wanted to check with the experts (that´s you!) to see whether there is something, perhaps more simple, that I may be missing as a means to assess these pieces for originality.

For example, a few thoughts that I had were:

Electrical resistance testing. Could an electrical current run through steel of original pieces be used to determine the originality of the piece (perhaps modern steel is significantly more (or less) conductive than steel used 70+ years ago. Are there instruments that could measure this resistance accurately?

Magnetic fields. Could the magnetic field generated by an antique item (for example) be used as a method of authentication?

I know I am grabbing at straws here, but anything non-destructive and portable would be fantastic to find.

Any other methods that seem plausible to anyone?

Thank you again and all the best,
John

 

[Guest102023]

I don't know why an alloy analyzer (a.k.a. PMI) keeps being recommended. These tools, while improving, still cannot perform exact analysis, and cannot even read the light elements (such as carbon, which I should think is crucial). It is an identification and sorting tool, and not much more. Just because a $40k instrument displays 2 or 3 digits on a fancy display does not make them all significant digits. That these digits get reported as such is one of the bigger embarrassments of the inspection industry.

The 'fingerprint' you are seeking is to be found in the structure - both coarse and fine. Think of the documentaries on samurai swords we have all seen - that's the sort of information needed. Unfortunately this tends to destroy large chunks of the object examined.

Even the most exact chemical analysis will not tell you how the elements are arranged and how the item was thermally/mechanically processed. Think of the composition as only the ingredients in a recipe - no matter how carefully you measure them, they give no indication of what the cake will look like.

 

[KENAT]

On the radioactive front, and given it's for museums etc. it may be worth seeing if any relevant govt agencies or labs can help out. Or even a commercial materials lab wants to donate some time - or maybe one of their scientists is a history/militaria buff or similar and could help out.

Perhaps even some university might welcome this as a research topic for some students thesis or something. You might even be able to get a grant or something to help.

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