12 replies to this topic

[Bart]

Making titanium control arms has been disscused before, in particular with toranamat69, but the last time it was discussed i dont believe there was a conclusion, but plenty of interest.

My biggest concern is what wall thickness to use to make a titanium tube control arm and what grade of titanium.

The best information i recieved was from a bloke in England who was making titanium control arms for a mini, which is significantly different to an LJ or LH/X/UC, in length and weight of the car, although he did use grade2 titanium.

[Bart]

Yeah i was talking about the front lower control arm but it shouldnt be limited to that, front and rear also.

[Bart]

From what I read it is not totally necessary to stress relieve titanium, but preferable I imagine.
The titanium the English bloke used was grade2 which could be why he doesn�t stress relieve his components.
Unfortunately his website doesn�t come up anymore
I have found a couple of titanium welders in Sydney but I haven�t spoken to them yet as I don�t have any titanium arms to weld yet.
I wonder if toranamat69 has found anything in regards to this.
I have seen titanium tube approx 14inches long, 1.25inch dia with 1.3mm wall go for about $40Au.
I was tempted to buy approx 6 peices but wasnt sure on the wall thickness and grade being right.

Edited by Bart, 16 April 2006 - 01:44 PM.

[Toranamat69]

G'day Bart, All my info I gathered on this is on my old PC which I was actually about to chuck out.

What I do remember is you are quite limited in the actual tubing sizes available in Ti.

Since I still didn;t know what shape and how the control arms will eventually look in tubular version, I have taken the choice of doing the development work on mine in steel and then upgrading later when I have a proven design. The Ti tubing was bloody expensive to be chopping up and throwing away dead bits.

My compliance engineer was not too worried by the prospect, just requiring I prove the strength of the tubing by calculation and having everything welded in accordance with the Australian standard.

The welders at the place I used to work were very proficient at Ti welding and there are a few special considerations you had to take into account but nothing really speciallised required to do the job.

You had to back purge the weld with shielding gas as well as the normal shielding gas on the face of the weld. You require an AC Tig as you need for alloy welding, the correct filler rod for the grade you are welding and don't try to weld any other types of metals to it as it doesn't work.

One of the best sources of threaded rod adaptors and Ti tube was a racing crowd I found in the US but I don;t have the link anymore.

Basically at the end of the day I concluded there are about 100 other things that make Toranas handle like crap other than the heavy unsprung weight.

Still something I may eventually do - on the rear lower arms first though as that would be relatively easy.

M@

[Toranamat69]

Just do do a bit of a backflip on the comments above about welding, I am currently reading 'Engineer to win' by Carrol Smith and with regard to Ti welding he states "Titanium, because of it's extreme reation with Oxygen when in it's molten state, MUST be welded in a chamber which has been purged of air and filled with an inert gas, usually argon..............A great many fabricators will now tell you that the necessity for welding titanium in a chamber is nonsense; that any good welder can weld up the stuff with a TIG and the argon turned up. NO WAY!, Don't even think about it. Sound and uncontaminated welds can ONLY be produced in an inert chamber."

So there you go Concept SS was onto it.

A speciallist should be able to do this for you as mentioned.

M@

[Bart]

Is an Inert gas chamber only used in American military? or are they used by welders in Australia?
I mean are they fairly common or rare and specialised with military??

[Litre8]

Wouldnt chrome-moly be a more practical alternative?

[enderwigginau]

Get onto TSS as they used to make Tubular arms - upper and lower - for Toranas. AFAIK they used Chrome Moly, but had issues with weld integrity and stopped making A-Arms for many vehicles.
They might be willing a lend a jig?? Worth a shot.

Grant..

[Bart]

chrome molly really needs to be stress releaved when welded.
titanium does not if welded properly ie in a chamber.
i dont think TSS will lend much at all let alone a jig unfortunatly.
I will find out more about this inert gas thingy and see who will be willing to weld it in this chamber, cost etc. I emailed SAMO Engineering, they look a little too flash but ill see what happens. http://www.samo.com.au/

Edited by Bart, 19 April 2006 - 11:17 PM.