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What is this welding process?

Janger

(John)
Administrator
Vendor
looks like TIG to me with a very short pulse. Somebody there commented on the video saying it is likely really weak. I agree. I've tried to weld like that without filler rod and not very successfully.
 

Dan Dubeau

Ultra Member
Autogenous Tig welding. Most if not almost all thin stainless is done this way. No filler is added, just fusing of the joint. I'm not sure if the video is done with a pulser, or by trick of the camera. The later is popular with some youtubers, and is done post process, making it look like some fancy pulse process.

The person in the video needs to resharpen that tungsten.....ooopps.
 
When I was buying my Primeweld TIG I serious looked at this and did my research. I short there is nothing that as a process that is cold welding. Heat must happen in welding.

This is a TIG process though its dressed up to be something its not.

TIG without fillers works in very specific applications, filler just makes up gap and adds strength.

Now @Susquatch if you can stick things together with MIG, you will love TIG its actually very controllable and getting a hint of your OCD this will be easier than MIG or Stick.

Just invest in a good TIG machine, I'll suggest the Primeweld, but to fair I have one.
 

Dan Dubeau

Ultra Member
I just checked out the prime weld tig225. Looks like a pretty feature packed unit for a low price. I'll have to keep that in mind if my squarewave 175 ever needs replacing or If one day I want some more features. I like that it's dual voltage. I bought my plasma for the same reason, and it's a feature that has come in handy a few times.
 

Janger

(John)
Administrator
Vendor
When I was buying my Primeweld TIG I serious looked at this and did my research. I short there is nothing that as a process that is cold welding. Heat must happen in welding.

There is another welding process which is quite cold called friction stir welding. Basically you put the two parts together and then run a spinning flat blunt stir stick ( say the back end of a 1/2” EM) into the joint and while spinning you push really hard. The metal heats and flows together stirring the two parts together. Pretty strange stuff. It’s used commercially in quite a few applications where distortion is unacceptable.

Long article here with many examples like rockets and aerospace.

 
There is another welding process which is quite cold called friction stir welding. Basically you put the two parts together and then run a spinning flat blunt stir stick ( say the back end of a 1/2” EM) into the joint and while spinning you push really hard. The metal heats and flows together stirring the two parts together. Pretty strange stuff. It’s used commercially in quite a few applications where distortion is unacceptable.

Long article here with many examples like rockets and aerospace.

John,

This is not cold welding, as it is stirred it creates friction and "heat" just enough to melt with minimal tranafer to surrounding areas.

True cold welding does actually exist. Example: SS nuts seizing in SS bolts. This is a form Galvanic Corrosion and basically welds the two together. I've experienced this on several occasions and trust me they are permanently fused.

NASA has concerns about this in space as it happens with even more materials in space.
 

Janger

(John)
Administrator
Vendor
Degen - well I said "Quite cold". ;) You got me wondering just what is the temperature for friction stir. One example I found is 450º C. (850F). Not exactly cold but colder than electric arc welding at 4000º C. It is pretty strange the metal does not melt but softens and flows.

These people make a friction stir temperature sensing instrument and produced this graph: https://stirweld.com/en/temperature-measurement-fsw/

FSW-rotation-speeds.jpg
 

Dan Dubeau

Ultra Member
I've done that with endmills before after fat fingering a tool offset, or clearance plane. Not quite as controllable as that one..... I'm convinced that's how the process was discovered though.
 
I've done that with endmills before after fat fingering a tool offset, or clearance plane. Not quite as controllable as that one..... I'm convinced that's how the process was discovered though.
So have I with aggressive feeds CNC with out cooling, hence flood cooling.

Though I must admit, while it binds the metal it is not as strong as a proper weld (in my case it was aluminium).

Now as to steel, there are enough examples where the steel gets up to those temperatures (and beyond) and no welding occurs.

What other information is important is that metal (among other solids) are actually a super viscous liquid and flow though at an extremely slow rate. Stir welding just uses that by pressure and a little heat to achieve the meld.

So this sets our current concepts of Solid, Liquid, Gas and Plasma on end.

I know that this will cause stir ;) (Pun intended).
 
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