material examination steelframe composition

[Ghiblicup]

Hello everybody!
Do we know the analytic steel/ferros composition of an original Cobra frame? Today these materials can be examined and analysed by pulling test sampling for example.
Does anyone know which results this should bring on a genuine Cobra frame?
I understand we are dealing with plain carbon steel as used in England by AC to produce the frames for Shelby .
Was a sample of an original car ever taken and analysed?

[Ghiblicup]

Really nobody?

No clue what the Chemical Composition Analysis should have as results?
Understanding that the steel used then was plain carbon steel, today's equivalent would be C22.
Does anyone have data on the genuine steel frused by AC? The components beside Fe: as C, Si, Mn, P, S, Mo and so on?

I can not believe that it was never tested to proof originality of a Cobra frame?

[LMH]

I've never heard of anyone testing original material used by AC Cars. Doesn't mean it's never been done, just haven't heard of anyone doing it.
Larry

[mickmate]

No one wants to cut a piece of metal off an original chassis to test it and see if it's original alloy composition. You'd be lucky to find what the alloy composition was even if it was the same supplier and alloy. They are an old tube frame car that rusts from the inside out, you can tell if they're original or not. There are many other features to check for originality ahead of that. You can measure about any hole and check the wall thickness. That would tell you whether it was made of the original metal.

[Bill D]

Your inquiry begs the question "Why?"

[rsk289]

I'd be very surprised if there was much in the way of alloy specification and choice back then. Knowing the British metal industry, I'm pretty certain the steel used would have been standard mild steel tube straight from the stockholder. Frankly, I'd be surprised if AC Cars knew any different at the time!

[CompClassics]

This is a common process used by Ferrari in their certification process.

[Tony Ripepi]

Hello All,

Don't know the answer but three shops come to mind that may be the definitive source for this information.

Mike McClusky, Kirkham motor sports and Canepa they do work closely on projects that involve complete restorations on originals from the round tube and bird cage out.

Best Regards,

Tony R.

[joyridin']

No need to remove any piece of metal from the frame. There is a hand held metal analyzer that can be used. All you do is hold it to the frame, and it will give you a complete readout of the chemical composition and what material it is.

Really cool stuff. Costs about $40k, but for a few companies, definitely worth the price.

[Ghiblicup]

O.k. guys, all interesting; but do we know the composition? Which ever method used to find the composition is fine - but what should specifications be like?
By the way @mickmate -. the tubes are surely not alloy - they are steel. We do have an idea of diamters and thickness, but that could all be reproduced. But nobody can find the same steel today as it was used back then, as steel compositions are changing all the time and get more advanced in terms of tensil strength and other physical characteristics.

I would not have a problem to cut out a piece of a frame in case. With values of these cars going up and up, anything to make sure you buy the "right" thing helps!
On engines, interior, even bodyparts there is no "real" proof. I mean "real" in the sense of 100% certification that the material is genuine. Also because at a genuine car they could have been replaced/exchanged or repaired during the car's life. But not the steel frame!

@rsk289: which were the specs of milde steel the British smelteries delivered?

@CompClassics: Yes Ferrari uses this method, and so does the Mercedes Classic Division e.g. with pre-war SSKs or similar stuff.

[ItBites]

Joyridin: I call BS

Ghiblicup: Steel is an alloy. Iron is not, but all steels are alloys by definition.

[mickmate]

An alloy is a result of mixing elements in various compositions to achieve the desired properties.

Carbon steel, also called plain carbon steel, is a metal alloy, a combination of two elements, iron and carbon, where other elements are present in quantities too small to affect the properties.

It has been done to original cars parts but I still stand by my original comment about not needing to as there are so many distinguishing features if you know what you are looking for.

[MOTORHEAD]

I have read of damaged "original" cobras being "re-framed" with non-original frames, and bodies too, for that matter.

[joyridin']

Originally Posted by ItBites

Joyridin: I call BS

Ghiblicup: Steel is an alloy. Iron is not, but all steels are alloys by definition.

What? You are full of bs? Is that what you are saying? Ok..I won't argue.

Metal Analyzer, Alloy Analyzer, Metal Tester, Portable Metal Spectrometer, Handheld Metal Testing Equipment for Metals & Alloys Analysis: XRF guns from Bruker Elemental

They work pretty cool. Shoots electrons at the material and bounces them back to the gun and determines the material composition by how fast the electrons are bounced back. Gets most metals accurate within 3%. Used it many times. The one I use costs about $20k and you can plug it into a computer to print the readout. Takes about 10 seconds.

[ItBites]

Joyridin: Thanks for the personal attack. I will not stoop to that, however, +/- 3% is not accurate enough to determine if the alloying metals are present in the small concentrations required. You can get close, but if you are looking to determine which Heat Lot of material you have or are trying to discriminate between similar alloys, that presision is inadequate. In aerospace this technique is not allowed by the Mil Specs for determining alloying composition. I wouldn't base million dollar decisions on it. Probably good enough for scrap metal dealers though.

[joyridin']

You did make a personal attack. Instead of just asking about the product, you had to say I was full of it.

And contrary to your theory, it is used in all industries. The company that has the product I use manufactures specialty bearings for all industries. I suppose if you need to find finite compositions, you might look elsewhere, but for 95% of the applications it is totally accurate. It can easily pick out one heat lot from another as long as you are determining chemical composition and not hardness.

It can pick out any type of stainless you put in front of it along with a breakdown of the chemical composition. I would say if you haven't used one, you really don't have a lot of talking room. For the topic on hand, it will easily determine the material used and the chemical properties.

[AL427SBF]

Originally Posted by ItBites

Joyridin: I call BS

Originally Posted by joyridin'

What? You are full of bs? Is that what you are saying?

Originally Posted by ItBites

Joyridin: Thanks for the personal attack. I will not stoop to that ...

"I will not stoop to that" ... too funny!

[CompClassics]

As I had previously stated, Ferrari performs a test of the vehicles frame during their certification process on classic Ferraris to make sure the vehicle in question has the Ferrari spec materials.

[ItBites]

Joyridin: My theory is based upon over 24 years of building rockets for NASA, the DOD, the MDA and commercial industry. The latest is a small vehicle called Antares - goes to the space station sometimes. And no, this device is not used by us, our suppliers, or our customers since it is not a Mil Spec allowed technique. At 3% accuracy, a user may think the composition is accurate, and an answer is produced, but the answer may well be wrong. The sellers do state on their website that this is used in Aerospace though, and we all know it has to be true because its on the internet. I have confidence you are using this device within its intended parameters and wish you the best, but I have looked at the specs and again wouldn't (and don't) base million dollar decisions on it.

[xb-60]

Mild steel is definitely an alloy as has been stated several times. Alloying elements are carbon, typically 0.04% to 0.07%, phosphorus 0.005 to 0.02%, manganese 0.18 to 0.25%, sulphur at 0.008 to 0.02%, and smaller amounts of silicon, aluminium, nitrogen....
A small change can have a significant effect on strength and mechanical properties.
Cheers,
Glen