Laser welding Ti?

[no704]

Anybody know much about it? Seems pretty specialized stuff! Probably better ways? I need a way to make a perfect seal on about a 2” length of .188od .150 I’d tube. With some pretty radioactive stuff inside of it.
All ideas will be appreciated!
Thanks!

 

[danski0224]

NSA has entered the chat...

 

[PCustoms]

Anybody know much about it? Seems pretty specialized stuff! Probably better ways? I need a way to make a perfect seal on about a 2” length of .188od .150 I’d tube. With some pretty radioactive stuff inside of it.
All ideas will be appreciated!
Thanks!

Well, made me look:

Thread 'Hard ****!!' https://www.garagejournal.com/forum/threads/hard-****.521362/

Doesn't your lab have some sort of protocol for these things? Or is it all done by advice on Google?

I've never done Ti, but done stainless. Not too complex, probably need some test pieces to get the parameters dialed. The trick (for you) I think will be welding it with whatever sealed inside.

Not exactly your everyday job shop project....

 

[oldmachinenut]

Plutonium suppository?

 

[PCustoms]

Plutonium suppository?

At least it won't be cold....

 

[no704]

Well we figure out things as we need to. Please visit our website. Servaenergy.com
I have found that if we don’t know about a thing or a process asking others about it is a good place to start.
Thanks for all the comments!

 

[rlitman]

The tube wall you describe seems to be in the reach of TIG, so have you tried that? Look up custom titanium bicycle frames. Every one I'm familiar with is TIG welded. They use a HUGE gas lens, though you can get better results in an argon purged glove box.

 

[danski0224]

Well we figure out things as we need to.

That's what the carbon fiber submersible guy said....

 

[slowtwitch73]

As mentioned bike frame builders (among others) routinely tig thinner than that. Gas lens, inner laminar purge, root pass no filler, then filler pass. get to know your pulse settings. Also sounds like a good job for some kind of rotisserie.

 

[no704]

I’m not looking to do this myself. Just looking at ways to get it done. I do have a friend that is a certified welder and works on nuke plants.

 

[bdbecker]

Is there a particular reason you are looking to laser weld the tube vs. TIG?

 

[no704]

Is there a particular reason you are looking to laser weld the tube vs. TIG?

Nope, just that it is a pretty small part, and would like to keep the haz as small as reasonable.

 

[bdbecker]

Nope, just that it is a pretty small part, and would like to keep the haz as small as reasonable.

Personally, I'd look for a skilled TIG welder. Laser welding is still in the early stages of adoption and you may have trouble tracking down someone who is proficient enough in the technology to do the job right, at least locally. You'll probably have more luck finding a TIG welder who can.

Are the ends of the tube going to be open during welding, or will they be closed off? If they are going to be closed off, you might want to re-think your approach. Trying to perfectly seal an enclosed container with weld is a recipe for failure. As the air inside the tube heats up during welding, it expands and needs to escape. The path of least resistance is typically through the weld puddle, which causes porosity (leaks). If the tube is filled material and there is little air in there, you might be able to pull it off if you take your time during welding and allow everything to cool before finishing the weld.

Also, if you need a perfect seal, how will you be able to test/verify it once welding is complete?

 

[slowtwitch73]

Vac chamber ^^^^

A google search will bring up everything the op needs to know and plenty of resources. This is not rarefied air.

 

[no704]

Thanks for all the good comments, this is still very much in the brain storming stage of things.

 

[Steve_P]

We had similar stuff done where I worked; used in similar environments; including using exotic materials like Invar. Everything was TIG, followed by a visual, helium, and radiograph inspection. You can xray tiny tubes by rotating and taking three shots. We had explosion bonding, spin welding, laser, (edit, and EB welding)..... done, but only when 100% necessary.

Are you writing a proposal? The reason I ask, is because we would never send a job like this to a shop that didn't have previous proven experience in doing something like this. Which is why we only dealt with a handful of shops in the US for specialized jobs like this.

edit 2: I didn't read any of the linked stuff

 

[no704]

Will for sure be radgraph. We are looking at a few different options. I really appreciate all of the input. This is why I love this fourm. Lots of experience here. It never hurts to ask! We have many other people than just me looking for the best solution to this challenge than me and you!

 

[no704]

Will be a SOP written, this will be done on a college research lab with plenty of oversight. We take this very seriously. And will be be scrutinized at length before being introduced into a nuclear reactor. But at the same time the need for Ac225 is real, and if we can produce commercial volumes of this isotope it could mean a cure for 70% of cancers.

 

[welder4956]

That's a pretty tough weld to make with manual GTAW - 3/16" OD x 0.019" thick. This could be made with an orbital tube welder like the ones made by Liburdi. Contact their main office near Charlotte, NC and tell them what you want to do and they will let you know the best solution. They have many years of nuclear welding experience both remote and mechanized.

Edit: This weld would also need a continuous argon gas purge on the inside to prevent oxidation. Be sure to include that in your procedure.

 

[welder4956]

If you are dead set on laser welding to minimize the HAZ, talk to Alabama Laser in Munford, AL. Ask for Wayne Penn or Sai Mudiam and tell them Marty referred you. https://www.alspi.com/laser-welding-services.htm

 

[no704]

Went to a local shop today to see a laser welder in action. Pretty cool! Like after doing a weld around a part about 1.25” diamator you could hold onto the welded area with your bare hand!

 

[MBfreak]

My son works with air flow calculations on a fighter jet development.
Once in a while he discusses practical issues with the body people.
Who regularly weld rather thin titanium parts.
Skilled TIG welders now have an experimental setup for laser welding of same.
Not approved for flying parts , yet.
Son says you can hardly see where the welds are made and NO fumes.

Ola