They are T4 very pure (High Oxygen), they are forged then heat treated...

Grades Description
Grade 1 Unalloyed titanium, low oxygen, low strength
Grade 2 Unalloyed titanium, standard oxygen, medium strength
Grade 3 Unalloyed titanium, medium oxygen, high strength
Grade 4 Unalloyed titanium, high oxygen, extra high strength
Grade 5 Titanium alloy (6% aluminum, 4% vanadium)
Grade 7 Unalloyed titanium plus 0.12% to 0.25% palladium, standard oxygen, medium strength
Grade 9 Titanium alloy (3% aluminum, 2.5% vanadium), high strength. Mainly aerospace applications
Grade 11 Unalloyed titanium plus 0.12% to 0.25% palladium, low oxygen, low strength
Grade 12 Titanium alloy (0.3% molybdenum, 0.8% nickel), high strength
Grade 13 Titanium alloy (0.5% nickel, 0.05% ruthenium), low oxygen
Grade 14 Titanium alloy (0.5% nickel, 0.05% ruthenium), standard oxygen
Grade 15 Titanium alloy (0.5% nickel, 0.05% ruthenium), medium oxygen
Grade 16 Unalloyed titanium plus 0.04% to 0.08% palladium, standard oxygen, medium strength
Grade 17 Unalloyed titanium plus 0.04% to 0.08% palladium, low oxygen, low strength
Grade 18 Titanium alloy (3% aluminum, 2.5% vanadium plus 0.04% to 0.08% palladium),
Grade 19 Titanium alloy (3% aluminum, 8% vanadium, 6% chromium, 4% zirconium, 4% molybdenum)
Grade 20 Titanium alloy (3% aluminum, 8% vanadium, 6% chromium, 4% zirconium, 4% molybdenum) plus 0.04% to 0.08% palladium
Grade 21 Titanium alloy (15% molybdenum, 3% aluminum, 2.7% niobium, 0.25% silicon)
Grade 23 Titanium alloy (6% aluminum, 4% vanadium, extra low interstitial, ELI)
Grade 24 Titanium alloy (6% aluminum, 4% vanadium) plus 0.04% to 0.08% palladium
Grade 25 Titanium alloy (6% aluminum, 4% vanadium) plus 0.3% to 0.8% nickel and 0.04% to 0.08% palladium
Grade 26 Unalloyed titanium plus 0.08% to 0.14% ruthenium, standard oxygen, medium strength
Grade 27 Unalloyed titanium plus 0.08% to 0.14% ruthenium, low oxygen,low strength
Grade 28 Titanium alloy (3% aluminum, 2.5% vanadium) plus 0.08% to 0.14% ruthenium
Grade 29 Titanium alloy (6% aluminum, 4% vanadium with extra low interstitial elements (ELI) plus 0.08% to 0.14% ruthenium

 

List of Titanium Grades

ASTM Grade Alloy Composition Min. Tensile (KSI) Min. Yield (KSI) Modulus of Elasticity (PSI-106)
1 Unalloyed Ti ("Pure") 35A 35 25 14.9
2 Unalloyed Ti ("Pure") 50A 50 40 14.9
3 Unalloyed Ti ("Pure") 65A 65 55 14.9
4 Unalloyed Ti ("Pure") 80A 80 70 15
5 Ti-6Al-4V13012016.4
6 Ti-5Al-2.5Sn12011516
7 Ti-0.15Pd504014.9
9 Ti-3Al-2.5V907013.1
10 Ti-11.5Mo-6Zr-4.5Sn1009014.9
11 Ti-0.15Pd352514.9
12 Ti-0.3-Mo-0.8Ni705014.9
13 Ti-0.5Ni-0.05Ru402514.9
14 Ti-0.5Ni-0.05Ru604014.9
15 Ti-0.5Ni-0.05Ru705514.9
16 Ti-0.05Pd504014.9
17 Ti-0.05Pd352514.9
18 Ti-3Al-2.5V-0.05Pd907015.3
19 Ti-3Al-8V-6Cr-4Zr-4Mo11511014.9
20 Ti-3Al-8V-6Cr-4Zr-4Mo-0.05Pd11511014.9
21 Ti-15Mo-2.7Nb-3Al-0.25Si11511014.9
23 Ti-6Al-4V ELI11511016.3
24 Ti-6Al-4V-0.05Pd13012016.4
25 Ti-6Al-4V-0.5Ni-0.05Pd13012016.4
26 Ti-0.1Ru504014.9
27 Ti-0.1Ru352514.9
28 Ti-3Al-2.5V-0.1Ru907013.1
29 Ti-6Al-4V-0.1Ru12011016.3

 

Most of the grades are of alloyed type with various additions of for example aluminum, vanadium, nickel, ruthenium, molybdenum, chromium or zirconium for the purpose of improving and/or combining various mechanical characteristics, heat resistance, conductivity, microstructure, creep, ductility, corrosion resistance etc. etc.

Palladium (Pd) and ruthenium (Ru), Nickel (Ni) and molybdenum (Mo) are elements which can be added to the pure titanium types in order to obtain a significant improvement of corrosion resistance particularly in slightly reducing environments where titanium otherwise might face some problems due to insufficient conditions for formation of the necessary protective oxide film on the metal surface. The formation of a stable and substantially inert protective oxide film on the surface is otherwise the secret behind the extraordinary corrosion resistance of titanium .

The mechanical properties of commercially pure titanium are in fact controlled by "alloying" to various levels of oxygen and nitrogen to obtain strength levels varying between approximately 290 and 550 MPa. For higher strength levels alloying elements, e.g. Al and V have to be added. Ti3Al2,5V has a tensile strength of minimum 620MPa in annealed condition and minimum 860 MPa in the as cold worked and stress relieved condition. The CP-titanium grades are nominally all alpha in structure, whereas many of the titanium alloys have a two phase alpha + beta structure. There are also titanium alloys with high alloying additions having an entire beta phase structure. While alpha alloys cannot be heat treated to increase strength, the addition of 2,5% copper would result in a material which responds to solution treatment and ageing in a similar way to aluminum-copper.

 

thanks.

btw, the only reason I put commercially pure in quotes is cause that's how it's referred to in the mil spec handbooks for metals. The type of Ti that I'm most familiar with is the grade 5 (6Al-4V), which seems to be the most common in various aerospace (civilian and mil) applications. Sometimes I get a little dissapointed when I try to find hardware in the real world (gotta keep reminding myself that the bolts I use at work start above the strength of "grade 10" commercial hardware, and go up from there...)

you wouldn't happen to know the spec for the steel used in the stock lugs, would you?

 

I am looking for the specs on the stock ones, as soon as I have will post...

Well been testing the car for a few days under different conditions and load and the bolts have done very well... Absolutely no problems and they are very strong; I can feel the difference with them on and with the new lighter wheels things should really start feeling good...

 

Ok, all the testing is done and we are going to do a production run of 10 sets of 20, will discuss with Omicron and post details later...

 

about how much are they going to run??? if not to bad, count me in for a set!

 

I am finalizing pricing and will post once I have everything squared away... The production ones will have forged heads rolled threads and they will be heat treated, even stronger than the prototype set...

The lugs bolts have speed starters on them for function, they also look really cool and if you ever use open ended lug nuts won’t ever rust or corrode…

 

Sounds like an interesting project, nice work. I'm curious though, under what kind of situations do lug nuts fail and how do these failures manifest themselves? Is it catastrophic, like a wheel coming off on a highway, or somehting recoverable. If one fails can it be easily replaced? Or does continued operation affect other parts?

 

All wheel lug bolts can fail but they usually fail independently; one at a time... The only way a wheel is coming off is if you hit something really hard (Really hard as in major damage to other components as well...) and even then it usually comes of at the spindle or the complete suspension assembly comes off...

If one fails it can easily be replaced and you can buy them individually if required...

These will be basically as strong as the OEMs while being much lighter and corrosion resistant...

 

what is the difficulty level of changing out the bolts???

 

Not sure if this has been mentioned before, but a google search for "Titanium lug nut" shows this link:

http://www.mettec.com/latemodel.htm

Specific RX8 stud size may be an issue here (I have no idea what size is needed), but off the shelf could be an alternative to custom titanium lugs...

 

The whole project is just amazing. I'm in for the group buy.
The price given a few weeks back by cort seems reasonable.

 

Mettec, does not have the sizes for the RX8 only Sprint car racing sizes...

 

Difficulty is a 5/6 on the 1-10 scale...

 

Ok, received approval from Omicron so the group buy will be posted tonight...

 

Hey Carlos, you think you can make me some Titanium Hurricane shutters

 

Alex, right after I make mine...

 

Ok, as promised here is the group buy link...

https://www.rx8club.com/showthread.p...435#post520435

 

Cortc,
What do you do about wheel locks?

 

I recommend some nice lightweight forged chromoly or aluminum open or closed ended lug nuts... The Kyokugen are very good and a set runs about U$49.00 + shipping, for those who don't want the hassle of getting them I can hook them up...

Here is a write-up on the Kyokugens:

https://www.rx8club.com/series-i-wheels-tires-brakes-suspension-55/kyokugen-lug-nuts-installed-29177/

 

pardon my english but when you say '...I can hook them up...' you mean you'll include the lug nuts in the group buy, for all those that believe in your projects

 

What I mean is I can include them in the kit for U$49.00 (My cost...) and no additional shipping... You will have lighter and stronger lug nuts as well...

 

^^To tell you the truth, I wanted to say exactly the same thing^^

I just wrote the whole thing wrong... still, nice to hear it!

 

These are still available if anyone wants some...