Help about titanium!

[Purple Welder]

Hi there, Have had a customer ask about titanium welding! Heard it behaves like s/s and needs purging. It will be tube. What tungsten is best? Many thanks

 

[arthur]

Its the price of the rods that will curl your toes

 

[eSCHEn]

Its the price of the rods everything that will curl your toes

FTFY

 

[hotrodder]

Search the TIG forum for titanium and you'll find a bunch of threads that go into more detail but basically it NEEDs to be properly, OCD clean and blanketed with argon because at welding temps it can be embrittled by pretty much anything happily forming nitrides, oxides, carbides and so on. Obviously depends what the part is for but even fingerprint oils are often a no no

While it's kinda like stainless to weld in many respects (if everything is clean and well shielded it's waaaaay nicer to weld than stainless IMO) the weldpool is sorta less fluid/more honey like and the filler wire has a tendancy to stick* to the weldpool, especially if you miss the pool/catch its edges. If (when) this catches you out you either contaminate the weld by bumping the tungsten into the filler or contaminate the wire by yanking it back to hard and pulling it out of the gas shield.

General/gross rule of thumb is that if it changes colour (heat tint) beyond straws/golds it's fecked although obviously what the part is for has an impact on what's acceptable

* kinda similar to what happens if you try and weld thin sheet steel or stainless with 2.4mm wire except its not because the weldpool is freezing and applies to Ti even if using 1.0mm wire on 1.5mm + base material

 

[Brad93]

Its not quite a simple as just purging the tube. Titanium if not properly shielded from the atmosphere on both sides of the tube will crack. You will need a good, even purge inside the tube, iirc you need less than 100ppm to obtain straw colour on the backside. you also need a gas lens that is going to give you adequate coverage on the outside of the tube.

 

[Jim Davey]

You might want to consider a trailing purge kit for your torch if you have a lot to do.

 

[Purple Welder]

Oh bloody hell, just the filler wire bit had my head fizzing! Then there is the contaminate part Thanks for the input

 

[Brad93]

Yeah there is a reason not everybody does it haha

 

[hotrodder]

The wire isn't really that spendy unless some 'posh' ELI (extra low interstitial) flavour is needed and those sorts of jobs don't typically turn up from random punters asking around for someone that can weld Ti. Some welding supliers sell erTi-2 in smallish quantities from per length (insanely spendy) through several quantities/weights upto 'full' packs. 0.5kg can currently be picked up for ~ £50 which sounds much better value when you remember that Ti is around half the density of steels and a pack of 12 magnesium filler rods that weighs next to nothing costs more than that

Obviously we don't know what sort of joints are involved but bear in mind that while trailing shields make LOTS of sense for butts (or fillets on sheet/plate) they don't really work so well on tube - tube fillets. If you think the wire is spendy price a trailing shield!! Just as well they're relatively easy to make

 

[Jim Davey]

Nice little project making a trailing shield but only if your time is less valuable than the money they cost as they can be fairly time consuming to make even if the materials themselves are relatively inexpensive.

 

[ronan]

I watched videos of it being welded, the welder used a very large perspex gas lens on tube, and a trailing shield on the butt joints. I believe if it gets air during the welding, a yellow oxide forms, so it easy to tell you've made a town-halls of it.

 

[Rrunnach]

My first taster welding Ti, was late 70's, no internet for a quick heads up, job was a complex component part for British Oceanics, Pisces V submersible. Welds on component were all fillets. I got my mate to hover purge line directly behind my torch hand, obviously he was wearing a bucket. Being a critical component, was sent for testing, nae bother, job was a good un. I really do have a good ol laugh at all the science of welding Ti posts.

https://en.wikipedia.org/wiki/Pisces-class_deep_submergence_vehicle#Pisces_IV_and_V

Pisces V https://en.wikipedia.org/wiki/Pisces_V

 

[hotrodder]

Straws/goldish heat tint is fine as is a hint of blue for many applications. Several other colour changes before you get a dull yellowish and whitish chalky deposit which IIRC are Ti nitrides and oxides respectively. Somewhere on the forum i posted a pic of the back of a scrap i purposly 'cooked' by running a bead without a purge

Nice little project making a trailing shield but only if your time is less valuable than the money they cost as they can be fairly time consuming to make even if the materials themselves are relatively inexpensive.

For sure they can be fiddly things to make but many of the commercially available are properly ropey looking things IMO. Especially given the asking price for example http://www.rapidwelding.co.uk/dynamic/Category.aspx?c=TRAILING&o=0&zl=2&sq=14 If i could earn £600/hour i might consider buying one The huntingdon fusion style look waaaaaay better quality but i expect they cost even more?

 

[Jim Davey]

Blimey, I've made a few and just taken on the CK agency so I've not checked out all the prices but at that money I expect I'll never sell one.

 

[Jim Davey]

There's a good video if you can stomach that patronising git Mr Tig.

And this one

Basically it needs to be clean, not overheated and completely shielded with argon until it's cooled past the point where it won't oxidise if air gets to it.

 

[hotrodder]

There's a good video if you can stomach that patronising git Mr Tig.

I'll have to take your word for it, that tit makes my blood boil

 

[arthur]

Ok just for fun here is some impressive Ti exhaust porn by Phil Smith at SPF, its for Steve Moore aka Motorapido's BSB bike for this years BSB (120 hours to produce)

 

[Rrunnach]

Beautiful!!

 

[Appyasme1]

We use the Eli grade.Had to change the post gas chip to allow more gas to flow at the end of the weld so it would not "blue".A lot of ground work was done by Dr David Harvey.Very clever guy.

 

[Wozzaaah]

Ok just for fun here is some impressive Ti exhaust porn by Phil Smith at SPF, its for Steve Moore aka Motorapido's BSB bike for this years BSB (120 hours to produce)

120 hours??!!
He needs a Clarke pipe bender, he'd have had that done in no time.