Possibly "Forge Welded" by a Black Smith.

Joe
A fair number of years ago I worked for a blacksmith as a striker. As we were in a city famed for it's historic buildings the large part of his work was making "wrought" iron gates and grill work for windows using time honoured processes. This fellow could fire weld a paper thin leaf to a vine that was thinner than coat hanger. Here is the basic process.
To fire weld or hammer weld two pieces of bar together you first taper both pieces to a three to one taper. Then you heat the bars to cherry red and dip them in borax. The trick here is the borax needs to be bone dry. My first job of the morning was to heat the borax in a iron cup till it was liquid then let it cool to an amber glass like stuff, then smash it up with a hammer till it was powder. If the borax is good and dry it will flow on the hot bar like honey if it has moisture it will bubble up. Then the bars are returned to the fire and heated untill they JUST throw white sparks. Too much heat and the surface burns forming thick oxide that wont bond together. When the metal is hot enough to throw white sparks you place the two bevels together quickly and then hit them with three perfect blows of the hammer. The hits are not hard but you need to hit like your trying to push it through the anvil rather than a sharp rap. The first hit is right in the middle of the joint, this squashes the flux and slag outwards. then you seal the first thin edge then flip the bar over and seal the second thin edge. Now you dress the joint with light quick blows. The main cause of failure is overheating the bar and burning the joint. For this reason the process is a lot easier if you use a true wrought iron which because of it's low carbon content is a lot more forgiving but you can use mild steel as well.
For reference try a book called "The Modern Blacksmith"

Tigger