Friction Surfacing
A solid-state additive cladding process where a rotating consumable rod is traversed across a substrate under axial pressure, plastically deforming the rod end to deposit a uniform coating. Since no melting occurs, crack-sensitive material combinations can be joined without dilution.
Friction surfacing is basically a rod that you rub over the workpiece with pressure. The friction makes the end plastic, i.e. soft and kneadable, and you deposit it as a layer. It doesn't really melt, that's the trick, so you avoid dilution and cracks, especially with materials that are tricky with normal welding. It's important to match pressure and speed cleanly. Too little pressure and the bond won't work, too much and you'll squeeze the material to death. The rod should match the base material in hardness, and you need to get a feel for the rod end deforming evenly. It's more of a rubbing and kneading process than a welding one, so don't compare it to normal arc welding.