black smith

Forge-welding is one of the most ancient joining technique performed for centuries by blacksmiths. It is a solid state process whereby the melting temperature is not reached.

Mighty hammer blows cause permanent deformation and assure metallurgical contact between two elements to be welded together. The main requirement for Forge welding is that the materials be forgeable.

That means malleable and deformable under pressure when hot, without cracking. Cast iron is not forgeable and cannot be forge welded. To perform Forge welding, the ends of two mild steel bars are normally heated together to white color in a coke forge, or forge charcoal furnace, fed with compressed air to enhance the temperature of combustion.

 As soon as the right temperature is reached, the bars are quickly withdrawn by two blacksmiths who stand at opposite sides of the anvil.

Experienced blacksmiths judge the correct temperature for Forge-welding and its uniformity throughout the material to be welded, by looking only at the color, without the help of any instrument.                                                                                 

The glowing ends are superposed, forming a bulge, and welded together by hammer blows stricken in rapid succession alternatively by the two workers.

In the intervals between blows the resulting welded bar is slowly rotated on its axis, to achieve uniform thickness.

Any occasional contaminant or oxide present on the surfaces is forced outside of the joint by the hammer blows, so that joining and coalescence occur on a clean interface.

In a few minutes the welding is accomplished, the bulge is brought down to the original size of the bar and coalescence is generally so good that no parting line can be detected.