Glen I can't type in that book it's still under copywrite; but you may be able to ILL it at a local public library.

Solid phase welding is like a 3 legged stool : Heat---Cleanliness----Pressure  max out any one of them and you can get a weld. Hence: Forge welding, vacuum welding and explosive welding and galling.  No melted metal needed.  You need to get the surfaces in such contact that they start sharing electrons.  If you get a real master of forge welding it's amazing at how cool a temp they can weld at.  As I once said "Billy Merritt can forge weld at temps I'd consider on the low side for forging".  I think the gradeau (Frank, how do you spell that?)  helps to keep oxidation from happening and cleans the surface as it's forced out.

Glen I can't type in that book it's still under copywrite; but you may be able to ILL it at a local public library.

Solid phase welding is like a 3 legged stool : Heat---Cleanliness----Pressure  max out any one of them and you can get a weld. Hence: Forge welding, vacuum welding and explosive welding and galling.  No melted metal needed.  You need to get the surfaces in such contact that they start sharing electrons.  If you get a real master of forge welding it's amazing at how cool a temp they can weld at.  As I once said "Billy Merritt can forge weld at temps I'd consider on the low side for forging".  I think the gradeau (Frank, how do you spell that?)  helps to keep oxidation from happening and cleans the surface as it's forced out.

All this makes perfect sense, but are you saying that all forge welds are solid-state welds? Is it not possible that your basic forge weld does indeed involve a liquid phase, but that increased mastery gives the ability to execute solid-state welds at lower temperatures?

All this makes perfect sense, but are you saying that all forge welds are solid-state welds? Is it not possible that your basic forge weld does indeed involve a liquid phase, but that increased mastery gives the ability to execute solid-state welds at lower temperatures?

This is an excellent question and brilliantly worded. I'm learning a lot right now. I've only ever forge welded cable to make a knife but I'm ready and eager to try it in other applications.

Yes that is my contention and why we call them forge welds and not hammer-fusion welds.   Patrick can you weigh in?

So then it is very likely that a lot of people are actually doing what you would call "hammer-fusion welds" and not a true forge weld?

This is an excellent question and brilliantly worded. 

Well, that's what a degree in Ancient Greek will do for you!

Yes that is my contention and why we call them forge welds and not hammer-fusion welds.   Patrick can you weigh in?

I'm sorry, Thomas, but which one is your contention? That all forge welds are solid state welds? Or that basic forge welds may include a liquid state, but more skilled smiths can produce solid-state welds at lower temperatures? Not quite the same thing.

(I'm not arguing with you, by the way; just trying to understand what you're saying.)

No because hammer fusion welds DON'T EXIST  You get that close to melting temps and you get cottage cheesing, splitting and all sorts of other failures as steel is not uniform on a microscopic scale, pearlite/ferrite/FeC all have differing melting temps

Get the book mentioned.  Then it won't be all greek to you!  (though it may be all geek to you then,,,)

Okay, that makes sense, but why then are we cautioned against hitting too hard when forge welding?

Bounce back.

Gotcha.

Thank you for all this. Very interesting, indeed.

I agree with Master Thomas.  As far as I understand, NO liquid state involved, even on the surface.  The "splash" is just slag or flux.  You can forge weld (solid state weld) at room temperature if your surfaces are perfectly flat and perfectly clean.  Tap a stack of machinist's gauge blocks together and they will stick if you clean off the oil.  Room temp "forge weld".

The Tylecote book is a very technical dry read but has some hidden gems.  

You can forge weld (solid state weld) at room temperature if your surfaces are perfectly flat and perfectly clean.  Tap a stack of machinist's gauge blocks together and they will stick if you clean off the oil.  Room temp "forge weld".

Is this just "in theory", or has anyone actually done this?

Try cleaning an aluminum screw with acetone and screwing it into a clean piece of aluminum. It will weld (gall). Yes any clean flat two like materials will join. Not difficult but disconcerting

Now I need a bit of help. Did this weld at all? What am I looking at? The nice gray areas, where they welded? Is it always possible to pry apart a forge weld?

I know you're asking "what am I looking for...in this trial to see if it welded at all" but as it seems it didn't weld (or weld enough) it's hard to point to something and say "that's what you're looking for", when it's not there to start with. It's easier to answer "what am I looking for?" by answering that in terms of what you should be looking for whilst welding.

For the sake of a bit of promo on my business Facebook page I drew up a step by step illustration of the process of fire welding an upset end on a component of a gate I'm working on. I've attached both below as it seems relevant to your question. My illustration doesn't match exactly what I've described for you as it was only aimed at the general public. Where the illustration clashes against what I've described for you, follow my description and not the illustration.

You don't need flux, I've never used it on any type of weld I've done. Without typing an essay and describing every single element of forge welding, in my opinion for the type of weld you tried / I have illustrated I would say the most important elements are:

- Taper the end of the bar before folding back so that the rear of the fire weld blends in and doesn't start to shear into the parent bar.
- When you fold your metal back before welding do not shut it flat, only shut the tip leaving the back of it open so any nasties can be ejected out.
- Weld the closed tip first, then put the metal back in the fire and bring it up to another welding heat, then start welding behind the tip.
- Flip it over to weld from both the top and bottom so if you do have a seam line at the side, it isn't eccentric.
- No seam lines is a good sign
- Stop hammering as soon as you lose the welding heat
- Multiple welding heats will give a better weld than 1 welding heat.
- Any work on the area you have just welded should be done a near welding heat.

 

Edited October 17, 201510 yr by Joel OF

Thanks Joe. And that is a very nice piece you made. It'll be next week before I can do any smithing but I sure will give it another try. 

I somehow managed to forget to say wire brushing before folding the metal back, after folding the metal back & inbetween welding heats is also going to help.

It is not necessary for there to be any liquid state between the pieces of metal in a forge weld, in the majority of cases in my work the forge weld is without doubt a solid phaze weld. I weld at 1250 to 1350CC the material I weld (carbon steel) is not molten until around 1450 and up.

 It is very hard to argue that there is no liquid phaze in  the traditional British no flux weld as the surface of the material is either slightly molten or burning (molten and heavily oxidising), However most if not all of the molten material is ejected around the shop when you hammer weld so the core weld is really still solid material to solid material. The sparking outside of the material is really there to allow the surface oxide to be gotten rid of.

 

 

My 3 legged stool for welding is Temperature and pressure and Time with the caveat that the welding occurs in the absence of oxygen or at least surface oxide. The Tylecote book is a good one , a shame its so expensive. I have bought multiple copies when I found it cheap and keep them as Smith- gifts.

 

Great Post Joel.