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Very strange question for the experts:

Very strange question for the experts:

Very strange question for the experts:

(OP)
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  

RE: Very strange question for the experts:

not sure but you may want to look at an alloy analyzer.  it will give you the material properties in percentages of elements present.

RE: Very strange question for the experts:

My advice would be to contact several material/metallurgical testing labs that have the capability to perform positive material identification (PMI), which requires the use of a portable alloy analyzer and inquire about your project. The x-ray fluorescence units will determine qualitative amounts of alloy elements present. This information must be compared to a known steel artifact composition to determine a comparative match. Be aware, there are significant limitations with the alloy analyzer, for example no element below sulfur can be detected (e.g., carbon content).  

RE: Very strange question for the experts:

Would a check for radioactivity help here? Some years ago I recall some manufacturers of gamma radiation monitors seeking pre-nuclear age steel since all steel since the start of atmospheric testing contained radioactive contaminants which interfered with the calibration of the monitors. I would think the contaminants must be at a very low level so the checking instrument would need to be very sensitive.

http://uk.linkedin.com/pub/terry-roberts/28/a9a/a10

RE: Very strange question for the experts:

(OP)
Thank you all!

I have looked into alloy analyzers and they seem ideal. I have access to several museums who could provide unquestioned original pieces for testing in order to create a database for comparison.

My concerns are only:
1) Is the analyzer accurate enough to detect minute differences in steel "source" composition?
2) Many of these artifacts date to the early 20th century. Was steel at this time refined to such an extent that there may be not enough other allows present for detection or accurate comparison?

Emax- You read my mind. I have heard this as well. In fact, I posted this exact question in the nuclear engineering section of this very website... no responses yet.
If you now the tools/methods by which such measurement of such radioactive contaminants could be measured, I would be very interested.
Also, is this actually a fact? :) My sourse was merely here-say.

Thank you all!!!!!
John

RE: Very strange question for the experts:

(OP)
PS: Sorry for the 2 spelling errors (allows/alloys and now/know), typing too quickly. ;)
I also cannot seem to find a way to edit my post and thus stem my embarrassment. :D

RE: Very strange question for the experts:

You will need to "fingerprint" a few known samples from Soligren (and other known sources). I think you will find the old steels will use higher Mn then modern steels. Also the Europeans were more likely to use V alloy. The trace contaminates from the ore are likely to help. Modern steels can be exceptionally low in S and P; Also the ratio of S to P may help. Al "fine grain practise" is likely to be a marker.
Sounds fun, you are likely to need an experienced (old) metallurgist.

RE: Very strange question for the experts:

About editing:  You can't.

However, if you Red Flag your message and leave a clearly worded request in the dialog box that appears, the site's magic bunnies will make reasonable edits.

 

Mike Halloran
Pembroke Pines, FL, USA

RE: Very strange question for the experts:

But, even if you COULD determine age based on composition, that would merely push the counterfeiters into the next level of complexity, much life they've done with counterfeit documents.  With documents, "washing" a worthless document from a particular era and putting age-specifc and composition inks for a more expensive document is par for the course.

Likewise, one could imagine that anyone sophisticated enough to counterfeit the look and feel of a turn-of-the-century metallit item would simply push on to duplicating the composition and heat cycles to fool the analysis.

TTFN
FAQ731-376: Eng-Tips.com Forum Policies

RE: Very strange question for the experts:

(OP)
IR Stuff - Thank you for your post and, good point. I have been thinking about this as well.

One key to success would be maintaining a "trade secret" database of steel composition from known original pieces. Without this information, the "unscrupulous" would need to invest in this testing equipment themselves, gather their own independent data, and then commission a steel manufacturer to duplicate the composition. Sounds expensive...

I believe that currently, this additional expense would make new pieces (able to fool the proposed analysis) too costly to justify.

I do concede however that should the values of these pieces continue to rise, in another 20 years values may reach a point that would justify the "unscrupulous" taking these additional steps...

In any case, at least this method could put us "1 step ahead"... for now.


 

RE: Very strange question for the experts:

(OP)
One other thought...

Many of these pieces are made of several parts, which in turn are made from different metals (blades from steel, but the crossguards, pommels, etc. are made from other alloy mixtures.

If the alloy analyzer could accurately measure the composition of these pieces as well, then the "unscrupulous" would have a much bigger challenge in creating a fake which could beat the analysis.
Not only would they need to get the blade metal right, but also the other fittings.

This might buy us another 10 or 20 years. :D

RE: Very strange question for the experts:

V
I have been associated with some archaeological metallurgy work.
With good modern hand held x-ray fluorescence analyzers you should be able to do most of what you have in mind.
You will need to do surface prep in order to get good readings.  But we are talking an area of less than 1/2".
You don't care how fast it is so you can allow long analysis times and get more accurate readings on trace elements.

= = = = = = = = = = = = = = = = = = = =
Plymouth Tube

RE: Very strange question for the experts:

v20102, interesting post.

Regards,

Mike

RE: Very strange question for the experts:

(OP)
EdStainless - Thank you for your post!

I was unaware that any type of preparation is necessary?
What would this involve?

In many cases, people do not want these pieces to be handled unnecessarily, so I am hoping for as little "touchie feelie" as possible. :)

I have contacted a few manufacturers and hope to hear something soon. They too however are probably puzzling over my intended application. :D

All the best,
John

RE: Very strange question for the experts:

(OP)
Also, how long a time period are you referring to with "long analysis times"?
Although, this should not be a serious issue.  

RE: Very strange question for the experts:

v20102;
Please do not take the following advice as criticism. As I stated earlier and will repeat it again, you need to have this work performed by a competent metallurgical lab. Unless you know the limitations of the machine and fully understand preparation requirements for a clean surface, you will obtain erroneous results.
 

RE: Very strange question for the experts:

Of course there are exceptions, but here are some generalizations that might help in screening for counterfeits or in building a database of ferrous materials.

Impurity levels:
Steel >100 years old will contain more impurities such as P and S due to 'dirty' processing (such as Bessemer or open-hearth methods), which are not as 'clean' as today's (electric arc or induction furnace melting).

Good points above in post # 22Jan12, 15:42.  Knowledge of the authentic steelmill's melting practice is desirable - what alloying elements (if any) were typically used; and did they 'kill' the melt with a few shovels full of sand (Si) or use Al instead.  All these would be easily detectable.

Due to the thermochemistry of steelmaking, certain impurity elements such as Cu and Sn (I believe), cannot be removed economically.  As scrap is recycled, these levels have risen over the last ~75 years.  

Radioactivity:
Not sure, but I do know that today's domestic steel production uses a huge amount of Fe scrap which itself may be pre-1945.  Also radiocarbon dating would only set the age of the carbon added to the melt.  (e.g., millions of years old.)  Still feel it should be pursued.

Non-ferrous metals:
JOM, a publication of the TMS, www.tms.org, once had a good article concerning ancient metals.  I don't recall the detail but you might check there.
 

RE: Very strange question for the experts:

A spot on the surface would need to be cleaned, or else what ever was applied (or happened to end up) to the surface will be included in the results.  Fine grit sandpaper is the most common method.

Long time for the new machines is a minute or two. The new machines actually contain miniature x-ray tubes and they can be tuned to optimize the results for various elements.

If you were in the neighborhood I would have you drop by and show you how this would work.

= = = = = = = = = = = = = = = = = = = =
Plymouth Tube

RE: Very strange question for the experts:

Following up on what Wrenchbender said, today's steels, especially electric furnace melted steels, will have higherlevels of residual elements like chrome, nickel, vanadium, etc. than the older steels.

RE: Very strange question for the experts:

Following up on EdStainless' comment:  Specifically, surface oxides alter the results; this is why such a technique requires surface preparation. This is fine when working on a part in the field, but you should be concerned regarding how this would mar the surface.

I hate to be a naysayer but I have little faith in using PMI for this purpose.  It can work if the alloy composition is so different from the original alloy that you would see a definite difference.  However, some problems include:

-More recent alloys may be similar or not have a meaningful difference in composition.

-PMI is a semi-quantitative technique.  It is good for identifying alloys, but cannot be used, for example, to determine if the alloy is in spec

-PMI cannot identify carbon, sulfur, or phosphorus contents.

Aaron Tanzer
www.lehightesting.com

RE: Very strange question for the experts:

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.  

RE: Very strange question for the experts:

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/

= = = = = = = = = = = = = = = = = = = =
Plymouth Tube

RE: Very strange question for the experts:

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

Aaron Tanzer
www.lehightesting.com

RE: Very strange question for the experts:

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.

= = = = = = = = = = = = = = = = = = = =
Plymouth Tube

RE: Very strange question for the experts:

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.

RE: Very strange question for the experts:

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.   

RE: Very strange question for the experts:

(OP)
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

RE: Very strange question for the experts:


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



http://www.scribd.com/doc/74132318/Metal-provenancing-using-isotopes-and-the-Oxford-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

RE: Very strange question for the experts:

(OP)
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

RE: Very strange question for the experts:

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.  
 

RE: Very strange question for the experts:

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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