Electron Beam Hot Wire Welding

In electron beam hot-wire welding, you preheat the wire before it enters the weld zone. This makes it softer and easier to lay into the seam that the electron beam is melting. You get a smoother weld and less spatter because the wire doesn't hit the melt pool cold. The advantage is higher deposition rate with better control over the weld shape. If you overheat the wire, it gets floppy and drips away. If it's too cold, you're working against resistance and the weld becomes unstable. You just have to coordinate the beam power and wire feed speed properly.