Cold welding, despite the name, is not welding.
I clicked on that Wiki link and it said cold welding is "welding process", and the hyperlink to the regular welding page includes solid-state welding, which mentions cold welding.
Normal welding is intentional application of heat to partially melt two parts at the seam, so that they "mix" in semi-liquid state and become one part when they solidify. Welding may or may not use a third material (solder) to aid the process.
Is the only distinction the intention, though?
Because I saw some examples of industrial applications of cold welding, so I'm still not quite getting why cold welding isn't considered welding (I have been googling since my original comment, but not finding anyone making this same distinction).
In a good weld you actually make 2 (or 3) pieces of metal into one.
Note explosion welding: you use a shockwave to hold the pieces together while aggressively dislocating grain boundaries. The result is a (very good) weld. Many glues involve welding behavior, especially if they are used without waiting minutes to hours for the bond to harden before loading it. For example, "contact cement" (polychloroprene glue) works by precipitating a polychloroprene layer from a solvent into the surface pores of both to-be-bonded parts, letting all the solvent dry, and then forcing such prepared surfaces together to cause intimate interaction of the polymer chains on the surfaces to weld into a single layer of polychloroprene that's solvent-soaked into both it's sides (which wouldn't be possible unless the materials are extremely porous).
However, solids are very bad at wetting surfaces, so you will have a hard time getting the needed atomic contact.
Welding isn't really applicable to composites like wood or paper.
Except for welding aluminum, where friction stir welding does exactly that to solid metal.
https://en.wikipedia.org/wiki/Friction_stir_welding
> Friction stir welding (FSW) is a solid-state joining process that uses a non-consumable tool to join two facing workpieces without melting the workpiece material.[1][2] Heat is generated by friction between the rotating tool and the workpiece material, which leads to a softened region near the FSW tool. While the tool is traversed along the joint line, it mechanically intermixes the two pieces of metal, and forges the hot and softened metal by the mechanical pressure, which is applied by the tool, much like joining clay, or dough.
And thanks for the additional details
Your description, and wiki's, both sound like it is welding.
And after spending an embarrassing amount of time last night going down a welding rabbit hole, I have not seen anyone else claim that "cold welding is not welding". I'm pretty sure it is.
Ok, "clean them in vacuum" is kind of a "now draw the rest of the owl" type of thing. But I wonder what's possible when you don't have an atmosphere to mess up the surface. Could you scrape off the oxide layer of aluminum, for example, and get it smooth enough to cold weld without worrying about it re-oxidizing because there's no air?
This is the hard part. They need to be flat to less than atom size over whole area, at least several square centimeters. We can't do that yet economically. If they are not so flat, your weld will be pretty weak.
BUT if you could make them flat enough and then wiggle them ultrasonically so that those almost flat surfaces rub the rest of bumps, that would probably not require a lot of heat and energy to make a pretty good connection.
And that's even assuming the solid you're working with is crystalline of the sort that can do this. Many materials are alloys meaning that cold welding would be further difficult.