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  1. #1
    pm
    pm is offline Senior Member
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    any ideas for non destructive testing on a finished part to tell whether titanium or aluminum? a vendor is showing me a small wire frame part which they claim is titanium. to me it appears to be anodized aluminum. any way to establish which without damage?

  2. #2
    eKretz is offline Titanium
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    Can you weigh it? You'd need to measure or calculate the volume. The density of Aluminum is .098 lb/in^3 and for titanium .170 lb./in^3. You could also check the electrical conductivity, as for titanium it is much less than aluminum. Not sure if the anodize would affect conductivity or not.

  3. #3
    Gary E is online now Diamond
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    Easy...no damage...it only gets wet..

    Read this...

    http://www.simetric.co.uk/si_metals.htm

  4. #4
    davidwest is offline Aluminum
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    take a half full graduated beaker of water and immerse the part. the increase on the gradiation is the volume of the part.

    weigh the part.

    now you can use the chart on the link posted above to figure what it is made of...

    (if im wrong im sure someone will tell me)

  5. #5
    kartracer55 is offline Aluminum
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    figure out its density

    g/Cm3 is the preffered method, or so I was taught to believe but I guess lb/in3 is acceptable as well, its just that gram scales are sometimes more common

    Jim

  6. #6
    Gary E is online now Diamond
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    a vendor is showing me a small wire frame part
    Define small...

    If we had an idea if it's size a better guess can be made on what to use.

  7. #7
    luthor is offline Cast Iron
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    This is the method I use to determine density of metals that I need to identify:
    1. Tare beaker of water(A)
    2. Weigh sample completely immersed, but suspended (by cotton etc.) in water.(B)
    3.Weigh sample resting on bottom of beaker (C)

    Approximate Density =
    C - A
    _____

    B - A



    This method, although not precice, will give quite accurate results.

    [ 06-19-2006, 09:35 PM: Message edited by: luthor ]

  8. #8
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    Hi David,

    That's correct, but to use the chart directly you need to calculate the density, which is
    weight / volume (actually mass / volume)
    in either si units or imperial.

    Leigh

  9. #9
    Acumen is offline Aluminum
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    Do you have access to a mass spectrometer? BTW, both aluminum and titanium can be anodized, as well as plasma etched/coated. Both of these surface treatments provide some degree of electrical and thermal insulation.

  10. #10
    eKretz is offline Titanium
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    g/Cm3 is the preffered method,
    Ok, so this is pretty simple to convert:

    For Aluminum;

    .098lb...453.592g......1in^3
    -------x------------x-------------=2.713g/cm^3
    1in^3......1lb.........16.387cm^3

    Note: extra periods there to format things into proper position.

  11. #11
    pm
    pm is offline Senior Member
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    hey thanks for all the replies -

    parts are approx. .05" x .125" x 6" , apparently forged with a variable thickness and profile.

    they are part of a assembly so I would have trouble getting volume of the individual parts in question.

    also am not sure I could get a accurate volume in a graduated cylinder with parts of this size (?)

    I have a fair amount of experience with aluminum but very little with titanium. to me the parts do not feel as ridgid as I would expect ti to be. comparable Ti parts I have seen feel harder and smoother.
    I know that sounds pretty vague but I have spent alot of time with my hands on metal and it is what my hands are telling me. parts are on a smaller scale than what I generally deal with so any method may need to be pretty low tech. any other suggestions???

  12. #12
    gradstdnt_99 is offline Hot Rolled
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    Rub the part against a piece of glass. Glass will scratch titanium, basically leaving a small mark on the glass. This would not be the case with anodized Al.

  13. #13
    Mike C. is offline Diamond
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    If it is hard to tell the difference and it is anodized, I'd say it is probably Ti. Blue, straw, purple, yellow, all typical Ti anodizing colors but they will appear more earthy than a blue or other color anodized piece of aluminum.

    Other than density (hard to measure something THAT small without some serious lab quality instrumentation) or the above scratch test (and that might even be slightly destructive depending on how you look at it), there is really not much else that can be done. You say it feels "not as rigid", but Ti is a fairly flexible metal. The big difference would be if it sprung back to the exact same shape. Ti is really hard to bend without heat. Also Ti is not really very hard. It is tough more than hard in most all cases.

    If you could sacrifice a tiny piece this would be easy. Touch it to a grind wheel. Brilliant white sparks if it's Ti. Dunk it in lye or Greased Lightning degreaser. If it comes out in one piece, it's Ti, as aluminum will dissolve. Heat it up with a propane torch to red hot. If it's Ti, it'll still be there if Al, it'll be a puddle as soon as the flame hits it. Walk in with the announcement that you are going to do any of the above and see if the vendor has a cow... heheh.

  14. #14
    Orrin's Avatar
    Orrin is offline Hot Rolled
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    It would help if you have a known piece of aluminum and a known piece of titanium to compare against your unknown.

    At Boeing Surplus there'll be chunks of titanium mistakenly thrown onto the pile of aluminum and they can be spotted easily.

    Aluminum weathers to a dull whitish-bright with a flat or matte looking appearance. Titanium tends to stay brighter and shinier.

    Regards,

    Orrin

  15. #15
    Gary E is online now Diamond
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    pm,

    You now know how to determine the material...

    If you still have no idea, send it to
    Laboratory Testing
    120 Mill St
    Dublin Pa 18917
    Phone 800 219 9035
    http://www.labtesting.com/

    Or you could give it to the local highschool physics teacher and have his class do it... It's really simple if you have the right equipment.

    But a couple of questions...
    Why is it that your customer who has this part, and lets supose it was made for him, why does he not have material certs?

    Spose he has no clue what it is, why does he not TELL you what to make another one from?

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