I did it! I welded nitinol wire!

I was very proud of my endeavor here. I wasn't sure if I was gonna be able to figure out how to weld this stuff together. As its proprietary, I wont give the trade secret on it. I will however say it has everything to do with controlling heat. Dont bother trying to weld it in mid air. The lowest setting on my 250 just kept melting the wire before I even came close to it with the tungsten. It is only .02" diamter. So I learned how to manage the heat a little bit. I'm sure most of you experienced welders could easily figure it out. Being I am still at my stage in the game I was surprised I got it to weld. Just needs a little grinding on the miniwheel. Its very strong. Ive put it under a lot of stress and havnt broken it. HeAttachment 1469Attachment 1470re is a pic of my nitinol wire loop.

Looks good.

You could likely resistance weld it, potentially using a capacitive discharge machine such as that used for welding thermocouples. This woudl probably give you the least heat afected area.

I would imagine that the shape memory of the welded area sill no longer be present.

When I had to ball the end of fine, K-type thermocouple wire, and I didn't feel like borrowing the dedicated machine from the instrument lab, I would just twist the ends together, three or four turns, trim them off, then hold them on the welding table with a scrap of steel, start a low amp arc on the table away from the twisted end, and carefully sneak up until the end melted to a nice little ball at the juncture of the two wires. (Sorry for the long sentence!)

ok, don't wanna sound too dumb here, but what is nitinol wire? what's it used for? I read something about thermocouple... is this the wire that changes resistance at different temps?

"I'm not afraid to ask dumb questions... they are easier to handle than dumb mistakes...." I think that was Ghandi or someone....

My thermocouple making example probably wouldn't work for nitinol. Not real sure, but it just might want to unwind as the heat from the TIG torch approached it's end. The metals used in K-type thermocouples are alumel and chromel .

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Originally Posted by ScratchStart

ok, don't wanna sound too dumb here, but what is nitinol wire? what's it used for? I read something about thermocouple... is this the wire that changes resistance at different temps?

"I'm not afraid to ask dumb questions... they are easier to handle than dumb mistakes...." I think that was Ghandi or someone....

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Im also curious to what its for... I do know ninitol stands for Nickel Titanium

http://en.wikipedia.org/wiki/Nickel_titanium

Shape memory wire

Thurmond

wow! good read thank you.

so is it possible to weld titanium? or was welding nitinol only possible because of the nickel?

lemme guess, your fixing your kids braces.... on their teeth.... LOL

Absolutely, Titanium can be tig welded. Jody over at weldingtipsandtricks.com has a video of titanium tig welding.

Thurmond