Titanium

[ronan]

What is grade 5 titanium like to turn and mill ? Is it as difficult as the legend suggests ? Also will it gall when threaded and screwed into steel components ?

 

[MattH]

It's a bugger, but does still turn nicely.
You've got to be aggressive with it and use insert tooling.
It heats up almost instantly so take that into consideration.

 

[CRB]

Titanium is remarkably soft, not quite copper, but a pain.

Like MattF says, keep it cool and heavy cuts. It is like a lot of plastics, it moves out of the way of the tool if you are too delicate.

 

[ronan]

What about the galling ? What other metals does it gall with apart from itself ?

 

[CRB]

I think aluminium, but am prepared for the obvious flaming. I suppose it is unlikely the two come into contact in their normal lives. I do remember the titanium nuts and bolts which we supplied were a really loose fit.

 

[MattH]

MattH. I only have one vice!

 

[CRB]

Brother of MattF.

We just need the one in the middle MattG.

 

[gordon stephenson]

I used to work on a Titanium plant for ICI. Most of it went to Rolls Royce for their aircraft engine parts, including the rotor blades. At the time Russia and Japan also made titanium but by a different process, Our titanium was considered a softer more suitable grade for highly stressed componants, the other makers titanium was harder and more used in the not so critical manufacture of bike frames etc.

 

[Maker]

Brother of MattF.

We just need the one in the middle MattG.

For what it's worth, there is actually a MattG .

 

[MattF]

Next time he logs on, he'll probably wonder why on earth everyone has been looking at his profile page.

 

[hotrodder]

I've never heard titanium described as remarkably soft before... all flavours of Ti are about 1/2 the elastic stiffness of steel (Young's Modulus) like aluminium is around 1/3 stiffness; even something like 7075-T6 which is harder/stronger than mild steel. Something like grade 2 (commercially pure) is a harder and stronger than low carbon steel while annealed grade 5 is significantly harder (36 HRC) & stronger than normalised chromoly. Solution treated and aged grade 5 gets up around 41 HRC and 170000psi UTS

Like stainless or ally fasteners etc galling is worse when in contact with itself but Ti fasteners will gall nicely into steel too. Cut threads are gonna be worse from a galling (and strength) POV than the rolled threads on commercially made fasteners
As said regarding machining it's a poor conductor of heat, the work will try and deflect/'spring about' more than steels (Young's modulus), it work hardens like mad and you don't a built up edge which compounds the heat/cutting forces/friction deal. Gross generalisation but i tend to think of Ti as being to stainless what stainless is to mild steel if that makes sense? It kinda works as an analogy whether folding/shaping the stuff (springback etc), welding it (cleanliness, shielding quality) or machining it

 

[ronan]

Is copper or lithium grease any use for the prevention of galling like it is with stainless ?

 

[hotrodder]

Yep along with various other flavours of assembly lube, anti-seize or anerobic thread compounds. Anything's better than nothing, the right flavour for the application can make a difference when trying to get the thing apart later though, lithium grease or oil getting washed/cooked out for example
If we're talking cut threads then worth burnishing the threads by running the fastener in and and out a few times with plenty of lube before final torquing too

 

[Maker]

For what it's worth, there is actually a MattG .

There's also a MattD . I'm pretty sure that's all of them... For now, Hopefully Matt's A and S will sign up soon.

 

[CRB]

Let us embark ona recruitment drive, Matts only.