Old steel

[Raf]

Is it old?
I didn't realise until reading an article recently that all steel manufactured after 1945 is radioactive. Not a cause for concern as the amount of radiation is minute but it does mean that post war steel is different to pre war steel . This is because processing steel uses large quantise of air or oxygen therefor some background radiation from atomic bomb testing is absorbed by the steel . Other sources of radiation can be radioactive materials used in furnace linings or contaminated steel inadvertently incorporated in recycling. This has led to a dubious market for pre war steel often savaged from wartime wrecks and Roman lead , both of which are in demand for some highly specialised applications that require materials entirely free from radioactive contamination.

Since the banning of atmospheric nuclear tests levels of background radiation have been falling and steel currently being produced can be considered virtually radiation free. Nevertheless any object that has been manufactured using steel produced in the last seventy years should show low levels of radiation which would not be present in something that purports to be genuinely old. So unless I have got it entirely wrong this would seem to be an entirely objective non destructive test that could be used to identify some post war forgeries. In the same way that TL testing is used to authenticate ancient ceramics. Anyone want to comment ?

[Teisani]

Originally Posted by Raf

Anyone want to comment?

Thanks for this little interesting fact! Unfortunately, I have nothing to add, but at a first glance, it seems like a workable method.

One question would be "are reasonably priced instruments sensitive enough to detect these differences?"

[Jim McDougall]

So ALL steel produced in modern 'Atomic Age' period is radioactive? Does this radiation only gravitate into the elements in steel production or is everything permeated with traces of radiation now that we are globally contaminated?

What sort of keenly specialized applications are you describing? Naturally I understand if this is classified.

The only thing I have heard of which caused concern with radioactivity was ceramic ware from Mexico in the 50s-60s called 'Fiesta Ware'. No idea how it was contaminated, uranium deposits in the area where other materials for production were found? Is it possible that radioactivity, such as present in areas where uranium or similar elements are found could account for such findings in metals? I think of Marie Curie with Radium in watches early in the last century.

Modern times have presented far more advanced methods of testing and analysis, such as the use of radiology in examining old blades nondestructively.

[midelburgo]

Just to add an anecdote, for building radiation detectors, they use steel from ships of the German Hochseeflotte sunk at Scapa Flow.

[CutlassCollector]

Originally Posted by Teisani

Thanks for this little interesting fact! Unfortunately, I have nothing to add, but at a first glance, it seems like a workable method.

One question would be "are reasonably priced instruments sensitive enough to detect these differences?"

That is interesting but like Teisani I wonder about suitable detectors.

We sometimes forget that radiation is a natural part of the environment.
There is even one known naturally occurring nuclear fission reactor at OKLO in Africa which has been running for millions of years.
Radon gas seeping into homes and the minor scare about radioactive granite kitchen worktops are other examples.

So old blades stored in granite houses may show traces as well from the natural environment as Jim has already suggested.

[Raf]

I tentatively launched this query in the hope that someone with specialist knowledge might be able to clarify. In response to issues raised so far.

1 Yes all objects are to a degree radioactive from natural sources . Average in UK about 3 MSV/ Hr but this varies a lot . Radiation from rocks like granite and other naturally occurring sources.

2. My understanding is that radiation in steel is introduced in the manufacturing process , either as a consequence of the process itself or contamination from other sources. Steel cannot acquire radiation through being exposed to sources of radiation, accept under exceptional circumstances like being at the epicentre of an atomic bomb blast.

3. A cheap Chinese Dosimeter claims to be able to measure from 0.00 to 1000 SV/Hr . So in theory any reading above the naturally occurring level of radiation where the test is being performed I would have thought indicate radiation present in the steel itself.

4. Historical levels of radiation in steel can be checked against date nails. Nails with coded heads used by utility companies until the seventies to date tag rail sleepers and poles.
And yes , sad people really do collect them . We are not alone.

[awdaniec666]

I wonder if you could provide a source for this theory (scientific study preferably).

As for my physics and chemistry understanding I have some problems with this claim.
Radiation comes from unstable isotopes (Variants of atoms). These isotopes emit radiation in form of small particles like protons or photons. When these particles land on another matter they do damage but dont cause the other material to be radioactive too in most cases. This is why we must use isotopes in medicine and cannot simply irradiate in some cases. A patient after external radiation therapy is not radioactive.
As long as you´re not forging these isotopes into steel (I don´t know whether this is so easy on an artificial/non natural level) a piece of steel should not be contaminated by higher radiation than its natural level caused by contamination with natural isotopes.

I´m of course open for scientific data proving other conclusions.

[Jim McDougall]

While I have little understanding of metallurgy, physics, geology and chemistry I find this topic most interesting and wanted to find more on the viability of this suggestion on radioactive emissions from forged steel from radiation in the atmosphere resulting from atomic bomb testing post 1945 .

While uranium and variations are naturally occurring in nature, it does seem that certain compositions of it, such as uranite, are highly radioactive. What led me to looking further into this is recalling from many years back, the ceramic dishware from Mexico known as 'Fiesta Ware'. It seems that the red and white examples had the highest radioactive content.

While Uranite is apparently not the same exactly as the uranium oxide and dioxides which were used for coloration in ceramic glazes on these dishes, it does seem that a degree of radiation was emitted from these ceramic wares.
Testing at Oak Ridge Labratories found that persons in the same room of tests were exposed to gamma radiation; if they touched the plates, beta radiation and if they ate from the, alpha radiation.

The concerns were mostly for the case for a subject ingesting from a damaged plate where the radioactive material could be ingested and contaminate the organs from the toxicity of the minerals.

The Fiesta Ware was produced from 1936-1943 using the uranium oxide component in the ceramic glazes. then WWII projects of course precluded such use. It resumed in degree but use of uranium dioxide (yellow & black) ceased in 1960, with the uranium oxide ceasing in 1972.
Apparently German scientists were busy using uranium dioxide as well for their efforts to achieve nuclear fission, resulting in a dramatic accident and fire lasting two days, near Leipzig in 1942 (this was preparation 38).

In other cases the Curies in Poland were experimenting with radioactive minerals to create radium and polonium in 1890s-1900s, the radium used to illuminate watch faces Madame Curie died of radiation poisoning.

While it sounds as if the cases for radioactive contamination varies depending on the elemental content of the minerals involved, case in point, uranite which is noted as highly radioactive and capable of this.

The use of these uranium compounds commercially, as well as in the controversial processes of nuclear power or fission seem to suggest that the processes and reactions from radioactive emissions which existed would vary but certainly existed dynamically rather than being inert basically.

Image Leipzig, 1942

[Teisani]

Originally Posted by Raf

2. My understanding is that radiation in steel is introduced in the manufacturing process , either as a consequence of the process itself or contamination from other sources. Steel cannot acquire radiation through being exposed to sources of radiation, accept under exceptional circumstances like being at the epicentre of an atomic bomb blast.

Iron and its alloys, in the molten state, do have a higher solubility for gases like oxygen, hydrogen, nitrogen than in solid state. Hidrogen is actually a big problem for high-strength steels which are susceptible to hydrogen-embrittlement. But the actual amounts entrapped are very small. See here an example in weld seams: https://www.youtube.com/watch?v=bv9ApdzalHM

Of course, other elements prezent in the atmosphere can theoretically be dissolved in the steel, while molten, maybe even radioactive isotopes resulting from man's nuclear activities. But the amounts would be extremely small (I would think much less than 0.001% by mass).

If the radioactivity levels are high enough to be detected, and the isotopes haven't all decayed yet, then I really don't see a problem with this method of dating steels, provided that some old steels were not made from iron ore rich in radioactive isotopes that would give false readings.

[Triarii]

Not my field but air is used (drawn in for Bessamer process steel or processed air used for more modern steelmaking) and that will contain minute traces of radionucliedes.

This is a reason that sunken pre WW2 era ships are especially attractive, apart from the obvious scrap value. Known as 'low background steel'. Parts of the scuttled WW1 German fleet at Scapa Flow has been used for this.

It's useful for tools that need to sense minute traces of radioactive material and for MRI scanners.

[Jim McDougall]

This is all fascinating, however I think the original premise here had to do with 'all' ? post WWII steel having minute presence of radioactivity due to circulating radioactive material from testing of A bombs.

The suggestion was that this radioactivity remained airborne and would be absorbed in the processing of steel so by testing sword blades it could be determined if they were indeed antique or modern reproduction.

It is understandable that radioactivity is naturally present not only obviously in uranium or certain other minerals in degree, but here the idea remains that contamination could come from trace radiation in the air.