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Weld setting on PW billet

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" relates compositions of the liquid phase to the solid phase in equilibrium with the liquid phase and that indicates temperatures above which only the liquid phase can exist."

in other words, depending on your outlook on life, it's the state where it is neither solid or liquid,, or it is both solid and liquid. above this temp range it becomes liquid and below it is a solid.

I learned this term at Turley Forge long ago. Ive discussed it many times with welding instructors as well. This is the first time it's ever been a discussion of definitions.Instead of argueing here, I suggest you fire off an email or text to Frank. I have  no doubt he can clear this up far better than me.

Correct me if I'm wrong, but this is what I've come to believe is "solid state welding". However It is not my area of great interest.

"Solid state welding processes are those welding processes in which no external heat is applied"

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Solid state welding reminds me of explosion welding where ferrous and non-farrous metals can be joined at the molecular level.

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4 hours ago, Ahaha said:

"Solid state welding processes are those welding processes in which no external heat is applied"

this is false

I don't know what you tube video you got this from,  but its garbage

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Oh, ye of little google-fu. Just because you can't do it at home, does not mean that there are not multiple industrial processes under the heading of solid state welding.

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Frank Turley is not doing so well lately and it is unlikely he would be able to reply.  I was up at the Turley Forge Oct 12 2019 when he was awarded the ABANA Heritage Award for 50 years of running his Blacksmithing school. (For those of you not familiar with it; I suggest you look up the previous winners to understand how big a deal this is!)

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That is concerning news Thomas, I'll add Frank to my prayers list.

Ahaha: Your grasp of the phase transition state is almost a usable working handle. Unfortunately your grasp of solid state welding is poor. 

As a quick primer so folks reading this thread don't get too confused. First, do some reading other than public media or opinion sites, maybe hit a library, you don't have to have a library card to take a book from the stacks and sit at a table or comfy chair and read. The librarians WILL be helpful. Don't take my word for it, I'm just another guy on the internet.

What makes metals conductors is their characteristic of easily exchanging electrons to and from the the electron's outer electron shell. An atom has more electrons than the one next to it so electron(s) migrate between atoms until they even out. A wire in the wall is exposed to a strong excess of electrons on one end which causes electrons to exchange down the line. No, the electron forced in at one end isn't going to be the the electron that comes out the other, eventually but not then. 

The better the conductor the easier it is for electrons to jump the gap but it still takes energy to make the jump, this is called resistance.  

Put two metals close enough together and atoms at the surface electrons will migrate back and forth even if charges are neutral. Picture it as sort of atomic brownian movement.  In time, sometimes measured in the micro even nano, nucleii start to migrate with the electrons and fluctuating charge at the surface. Soon the metal pieces are one piece. Welded.

The states necessary to weld metals are: Proximity, Close enough, Force, pressure, heat. Enough of any one of these states will weld metal particles together. Clean enough and the atoms at the surface are close enough to exchange electrons as a function of their normal movement. Enough pressure just forces atoms into CLOSE contact and electron and atomic exchange occurrs. Enough heat and the movement and exchanges accelerate causing touching metals to weld. 

Two clean, polished pieces of steel put in contact will weld. My Father's Jo Blocks were a prime examples. They are used to calibrate instrumentation, mics, height gauges, calipers, etc. very precisely, Dad's were regularly inspected and certified to 0.00001" Each block had it's own pocket in the box and was wrapped in oil paper. If you let them touch they welded almost instantly, the film of oil was no obstruction. Dad fired more than one guy for stacking them. Finally only he his business partner or Glen the shop foreman were the only ones to use them, kept them locked up. 

Being in the phase transition state makes welding very easy and often found on the anvil. It's what we usually shoot for it makes clean and force much less necessary. There's no need to bother yourself with thinking of phase transitional states, electron and neutron migration at your forge unless you like thinking while you wait. All you need to concern yourself with is meeting one or two conditions, the more the better of course but any two works a treat at the anvil.

Frosty The Lucky.

 

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Frosty, i just read a a very interesting article about solid state welding it said that one of the other things needed was time. From nano seconds to hours depending on the process. The article was from a metallurgical someplace or other (cant remember off the top of my head) Forge welding is considered a solid state way of welding. They also mentioned explosive welding which sounds fun along with friction welding which is how drive shafts are welded. 

Quite interesting about your fathers shop and his gauge blocks, explains why when i worked in a machine shop they were sticklers about keeping them in the wooden box the way they did. 

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Oh boy, Frosty please tell me you copy and pasted that and don't have that memorized:o I don't think I could handle the jealousy of the knowledge you posses. Seriously though that's a great run down and example. I study what I can when I can but I am not the best at it so I really appreciate the little blurbs like this you and others share here. Ok back to reading I go :) 

 

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I believe I have already mentioned Tylecote's "Solid Phase Welding of Metals"; I remember lending my copy to a metallurgy student who now works as a metallurgist (and who returned it in a timely manner!) 

As far as explosive welding goes---they do quite a bit of it here at EMRTC, Energetic Materials Research and Training Center on the NM Tech Campus. (I take the Explosive Laden Vehicle bypass into Campus every work day.  Lovely road and folks are usually quite polite driving on it...)

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