Titanium alloys

Discussion in 'Materials' started by zerogara, Jan 19, 2006.

  1. Pavel
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    Pavel Junior Member

    titanium

    There is a good book about Titanium and its alloys called, what a surprise: Titanium and titanium alloys.
    http://www.amazon.com/gp/product/35...103-4958322-7629417?s=books&v=glance&n=283155

    its rather costly book, so to safe your time and money I will summarize what is of concern for boat building:

    1. they say that Japanese have made one 12m long fishing boat in Titanium alloy. That’s it, I could not find any other info on the web (please post a link if you could).
    2. As for forming: there is a possibility to do round hull shape in Titanium alloy. Its called superplasticity and it in principle involves to heat the plate to somewhat like 1000C+ for a while and then suck it into a negative form – made of good quality hi-temperature steel. Not cheap this business, but I would be really interested to hear of anyone who is willing to spend money on this, I think I can be of some help.
    3. Price: is hugely dependent on volume, what the book says is that in volume Ti could be as expensive or cheap as more expensive stainless steel, but volume means an oil extraction platform in the North Sea or similar, not a few tons needed for a hull.

    Well, that’s about boats in this book, apart from what was already said above.

    D’Artois: could you please elaborate on the welding of AlMg4,5 direct to Ti-6Al-4V? What filler and what technique you used (TIG/MIG? – it matters a little). Thanks!!!

    Regards,

    Pavel
     
  2. D'ARTOIS
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    D'ARTOIS Senior Member

    Pavel,

    If you read my observations carefully in my first post you will see that I mentioned that already and that the best way to form Titanium is by pre-heating it in a way that does not involve release of moist/oxygen. An electrical oven is the best way, or infrared.

    Heating it up to 1000 C+ is not required; 600 C suffices.

    For welding AlMg 4,5 on the Ti sheet we used regular filler and the system was Mig/Mag. The burn-in was good and the weld was of acceptable quality.
    We put the testitem in the testbench and tore it apart. The aluminium gave away, but only after the weld, not on the weld itself.

    Note: this was not done under laboratory conditions but plain under shipyards everyday practice.
    These tests were performed at one famous yard in Holland. By top professionals. To check if it was feasible to build a boat out of it.

    The testing was done under my conduction.

    Furthermore:

    There excists alloys that we do not know about.
    Whole laboratories in the ex-USSR were involved in the creation of all kinds of alloys for military purposes only.

    I have a list of some of the Ti alloys they have created and together with the specs it gives a picture of what is feasible and not.
    After the collapse of the USSR a sell out started of material technolgy as well as the real-time products.
    The large Titanium factory in the Urfal area was the first target of the US aerospace industry and as a direct result the prices of Ti metals soared up.

    The positive side was that this factory received all approvals that are necessary to sell their products to the international market. If you are not an identified supplier, it is impossible to sell your products in the aviation industry, therefore the many forgings that occur.

    Now aware of their value on the international market, the prices are spoilt.

    It was in such masses available that the Russians provide a complete class of ISBN's fitted out with a double titanium hull of 2,5 till 4cm thickness, emty weight of 6000 tons.

    Can you imagine the value of 6000 tons titanium? In a single boat? Today?
     
  3. Pavel
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    Pavel Junior Member

    superplasticity

     
  4. D'ARTOIS
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    D'ARTOIS Senior Member

    Sorry Pavel,

    No, I didn't know this excisted, so we can learn from all; I believe I should buy this book because titanium (and boron as a new age metal) interests me a lot.

    I would say it is rather strange that all research of new materials go in the way of plastics. But in some time to come there will be no more oil and no more plastics.

    Did you know that the heatconductivity of the Ti-6V is almost nil?

    We did eproof with a strp of Alu and a strip of Ti: gave it to a guy to hold up: heating up the alu with a gaslighter the guy dropped the alu strip within seconds;
    the whole content of a gaslighter could not heatup the Ti enough for the guy to drop it.......
     
  5. Pavel
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    Pavel Junior Member

    Titanium superplaticity

    Well, I was also very interested in Titanium in general and boat building issue in particular some time ago, and it was not exactly the cost of the Titanium itself which put me off, but the terrible manufacturability problems we encoutered. We know a few guys building Ti-bicycle frames and components near to us and unless one can use right technology which is costly moneywise and timewise alike... it does not seem to make much sense at this point of time (at least my time to say the least). But for sure, Ti is a mirracle metal on its own... anyhow...

    D'Artois, I was thinking about that welding of Al/Ti ... cant get around a potential galvanic corrosion issues. I know that Ti is not so bad in the real world as the potential table would suggest, however, welding nobel metal onto aluminium... sounds exiting, say, one can think of a framing made of Al and the shell of Ti, but ... any info on corrosion issues of your welding experiment you can share ;)
     
  6. zerogara
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    zerogara build it and sail it

    Keep it quiet, let's sell the idea to Zippo!
    Have you guys been burned by one of those pretty and otherwise useless cowboy contraptions :)
     
  7. MRRPM
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    MRRPM Junior Member

    The Ti boat seams duable. But here is the hidden facts. building it is nor a problem. Welding it eather. I weld Ti all the time. If you make it out of 321 stainless instead of ti. You do not need a special welded to repair any part of the boat.
    Most job shops say they weld TI! Look at there filler wire selection. and you willl see a different story all together. Now obtaining the Ti and machinging it. Is more difficult than you would think. Most maching shops do not have the tooling to di this. I do some machinging no ti. You can hold better stresses with ti. the cold element wears better than hy80 and hy100 and greater.
    This is only my opion
    :p :p Robert
     
  8. D'ARTOIS
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    D'ARTOIS Senior Member

    You confirm what I know; what alloys do you weld and what's the application?
     
  9. MRRPM
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    MRRPM Junior Member

    I should refrase my statment. I myself would use stainless instead of ti. As most any shop would be able to weld it. The cost of reproducing it are mild compaired to Ti.
    Now think about this go a step further and build it out of magnesium supper light and strong. Welds like aluminum but has more strength and could be machined easley.

    Robert:idea: :idea: :idea: :idea:
     
  10. kach22i
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    kach22i Architect

    What have you found on this topic up to this date?
     
  11. MRRPM
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    MRRPM Junior Member

    There is a process called flame spray that is applied to aircraft engines. it is liquid metal. I don't know very much about it. United air lines uses it exclusivly
    on there hearer sections of the engines.
    robert
     
  12. Wellydeckhand

    Wellydeckhand Previous Member

    Is it high velo Zinc composite hot spray that bang at the material at approx. 200 km/hr?
     
  13. MRRPM
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    MRRPM Junior Member

    I really do not know what it is or what metal alloys they are.
    ROBERT
     
  14. Wellydeckhand

    Wellydeckhand Previous Member

    Hot spray

    It may be a ceramic coating:confused:
     

  15. DanishBagger
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    DanishBagger Never Again

    http://www.walshbrothers.co.uk/Update/Titanium-Zippo.htm

    They already did. However, I believe the innards are still made from tin.

    Andre
     
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