Last weekend I attended I was in Abu Dhabi attending the GP. Whilst there I was looking at part of the exhaust system for the Williams' Toyota engine. The chap on the stand said that it was made of steel which surprised me as it only weighed a couple of kilos, I would have thought it was some kind of titanium alloy? My mate who was there with me and is a material scientist thought it was aluminium.

Any ideas?

F1 exhausts are usually made from sheet Inconel, a titanium alloy. I've a lot of respect for the guys that make them, real artisans of the old school type.

Objects of great beauty. And aluminium would probably melt, I seem to remember that MP is 660° C. Had some on my foot once...

No, Inconel is a nickel based superalloy. Inconel 625 tend to be the standard in high performance exhaust design since it's reasonably easy to fabricate and weld. Inconel 625, made by Special Metals, contains 58% nickel, 20-23% chromium, 5% iron, 8-10% molybdenum, 4-3% niobium and small amounts of other elements. Inconel is a common material for applications that require good heat and creep properties, most of them originally developed for gas turbine engines. Inconels density is slightly higher than that of steel, but since the exhaust can be made with a thickness below one mm their weight is very low.

The trade name Inconel comes from International Nickel Company, Inco, which later merged with Mond Nickel (known for the Nimonic alloys), which later was aquired by Special Metals.

http://www.specialmetals.com/documents/Inc...alloy%20625.pdf

Titanium would not survive as an exhaust pipe material in F1 as it oxidizes rapidly after 600 degC. Aluminum melt at around 660 degC and lose strength rapidly at above around 200 degC (depending on alloy). An exhaust has to withstand temperatures over 900 degC.

Without looking it up I'm pretty certain Inconel- which is the stuff F1 exhausts are made of- is mostly Nickel and contains no Ti whatever.

<got beat to the punch!>

Cheers guys, your a clever bunch aren't you? Am I right in thinking that nickel alloys are used heavily in jet engines?

Yes. Only surpassed by ceramics for temperature resistance. (but superior to ceramics in many other ways - Ceramic f1 exhaust would be difficult)

Nickel and cobolt based superalloys are used for the hot parts of a gas turbine engine, such as turbine blades. Parts subjected to lower temperatures are often made from stainless steel, and parts subjected to even lower temperatures such as compressor blades are often made from titanium alloys. Many of the same titanium alloys are actually used for valves in racing engines. Low temperature castings are often made from magnesium or aluminum while the shafts are high strength steel.

Don't think Alu would actually "melt", but it's too soft anyway.

It would melt!

I am presently helping an aerospace company with tool inserts for inconel.

They usually use some expensive ones from England that lose the edge every 50 mins of work time but then sourced some from China that were much cheaper but last just 30 mins. I have sent those to a University friend of mine here to see whats up and how to harden them up (maybe I should send them to Chopper Read?).

The part mostly made is part of the fuel line and the inconel wears better. Apparently the way to machine them (CNC in this case) is to go in hard and fast, so hard that they scream like hell and it goes against most machinist's instincts to do so.

Have you contacted Sandvik and/or the other insert manufacturers?

Speeds and feeds are a big deal, but it is easy to go too fast and bend the peice being machined. Machine stiffness is also a problem ... sometimes the insert manufacturers (e.g. their salesmen) cause problems by pushing speeds and feeds that are too high. Everyone wants faster cycle times with improved quality and longer insert life.

Lastly, IME it is machined in the hardened state (is "gummy" in the nonhardened state) and therefore it is a good idea to try to get it close (within reason) prior to heat treatment so that final machining is a small cut.

Once you get the machine dialed it, lock the controls so the operator cannot screw with it. We had problems with machinists "tweaking" the program and causing all sorts of hell will piece part quality.

YMMV.

I once saw a website of a company that claimed to have developed a composite(carbon I think) material that exhausts could be made from, does anyone know about this flame proof high temperature material?