mirrodie
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Titanium On Commercial Aircraft?

Sat Nov 02, 2002 2:42 am

I read an article that nowadays, the latest craze is to have wedding bands made of "Aircraft grade Titanium."

I was underthe impression that certain military a/c use titanium for parts.

Are there parts of commercial airliners that also are made of titanium?

thanks.
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broke
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RE: Titanium On Commercial Aircraft?

Sat Nov 02, 2002 3:30 am

There is titanium used on the commercial airplanes that I have worked on (Boeing, Douglas, Lockheed, Airbus). There are two basic types used on these airplanes; commercially pure titanium, which is surprising not to strong and is used where structural strength is not a big requirement; and titanium alloys which are used where structural strength in a tight spot is a requirement. The most commonly used titanium alloy is one with 6% aluminum and 4% vanadium as the alloying components.
This alloy basically has the weight of aluminum with the strength of steels. Titanium is expensive and difficult to work and form, but its modulus of elasticity is almost the same as aluminum while steel is 4 times higher; so in critical applications where strength and space along side aluminum parts is a requirement, titanium is better than steel for good fatigue life. The modulus of elasticity is an indication of how much the material will flex under load, if one material will flex more than another, then the stiffer material is more likely to crack over time. This is a common problem where steel sheet is used to reinforce aluminum skin around door corners, for instance. Titanium is much better both in the initial design and as a repair material, but the cost and difficulty in forming discourages many from its use.
Also, there is a lot of titanium used in the compressor sections of turbine engines; here the high strength with low weight is the reason for its use.
 
Ikarus
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RE: Titanium On Commercial Aircraft?

Sat Nov 02, 2002 5:51 am

Titanium alloys are used for turbine blades (due to excellent creep resistance), for landing gears (777) and other strength applications that would conventionally be made of steel. Ti alloys offer a weight saving, but generally require more volume.

Russian aircraft designers use Titanium with a lot of pleasure - simply because they've got lots of it and it's cheaper there...

But generally, the future is in composites. Titanium will probably remain marginal - used only where aluminium is not an option and where it offers savings compared with steel.

Turbine blades will hopefully, one day, become dominated by ceramics (currently impossible due to brittleness and certification issues - the things aren't bird strike proof! But, ooooh, the heat resistance! Could spurt an entirely new, more efficient generation of engines...)

Regards

Ikarus
 
si02y
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RE: Titanium On Commercial Aircraft?

Sat Nov 02, 2002 7:41 am

The earlier stages of a typical aircraft gas turbine usually have aluminium compressor blades, but as the pressure increases, aluminium is not able to withstand the higher air temperature. As such, the later compressor stages usually have Steel or Titanium alloys for the blades.

Turbines are usually made of nickel based alloys, with a sprinkling of exotic elements such as Rhenium, Yttrium, Colbalt etc. Yes, ceramics have been touted as the future material for the hot section of gas turbines. Ceramics are already used in turbine wheels for automotive turbochargers that have spin rate in excess of 200,000 rpm.
 
galaxy5
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RE: Titanium On Commercial Aircraft?

Sat Nov 02, 2002 10:25 pm

Alloyed with aluminum and vanadium (aircraft grade titanium 6.4), titanium is used in aircraft for firewalls, outer skin, landing-gear components, hydraulic tubing, and engine supports. The compressor blades, disks, and housing of jet engines are also made of titanium. A commercial jet transport uses between 3500 and 12000 kg (7000 and 25000 pounds) of the metal. A supersonic transport uses much more, between 14 to 45 metric tons of titanium
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delta-flyer
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RE: Titanium On Commercial Aircraft?

Sun Nov 03, 2002 10:36 am

Ti is used extensively on new and future aircraft for high pressure hydraulic tubing and fittings. Watch for it on the A380 and SC, as well as on various RJ's and bizjets.

Pete
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Alessandro
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RE: Titanium On Commercial Aircraft?

Sun Nov 03, 2002 6:29 pm

The thing with titanium is that it demands high temperatures when you refine it from titanium ore (for example by the Kroll method). Energy is something Russians have a lot in certain regions, thats why titanium is less expensive in
there. The titanium ore isn´t that rare so its the refining methods that makes it expensive, as for titanium being used in wedding rings, other use is in golf clubs, bicycle frames, nuts, bolts and so on....
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737doctor
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RE: Titanium On Commercial Aircraft?

Tue Nov 05, 2002 10:32 am

We use a lot of titanium hardware and it's rather expensive. The other day I was rebuilding a forward service door torque tube and the IPC called called out for titanium bolts. There is a service bulletin which states that the steel bolts should be replaced with titanium ones. I've also seen a lot of titanium screws used to install cabin floorboards. Some mechanics were in the habit of throwing away perfectly good screws away after removing the floorboards, unnecessarily costing the company money.
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Accidentally
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RE: Titanium On Commercial Aircraft?

Tue Nov 05, 2002 12:24 pm

I have a load of titanium in my neck from a spinal fusion...
Indianapolis, IN
 
mirrodie
Posts: 6789
Joined: Wed Apr 19, 2000 3:33 am

RE: Titanium On Commercial Aircraft?

Wed Nov 06, 2002 2:55 am

Sorry to hear about that accidentally.

I take it that no one here has titanium jewelry. But since that is a different discussion, I will focus on that topic in non-aviation.

Thanks for your replies. I did not realize that this metal was used so much in a/c today.


Can any of you point out particular commercial aircraft types today that have titanium on them? Particularly on the outer skins?

Thanks, mirrodie
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FLY777UAL
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RE: Titanium On Commercial Aircraft?

Wed Nov 06, 2002 7:23 am

I have a titanium ring. It's amazingly light weight, too...that's the first surprise when I was given it. Expensive as hell, too! My girlfriend gave it to me and the first thing she said to me, (knowing my obsession w/ aviation) is, "it's what airplanes are made out of!"

It's the "apex" design from www.titaniumcommitment.com

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