电子束焊接是一种利用电子束作为热源的焊接工艺。

电子束发生器中的阴极加热到一定的温度时逸出电子，电子在高压电场中被加速，通过电磁透镜聚焦后形成能量密集度极高的电子束，当电子束束轰击焊接表面时，电子的动能转变为热能，使焊接件的结合处的金属熔融，当焊件移动时，在焊件结合处形成一条连续的焊缝。

A stream of electrons is emitted from an incandescent cathode and accelerated by a high voltage between the cathode and anode and converged by passing the magnetic lens on the work piece. During bombarding work piece, its kinetic energy converts into heat. The  power density is so high ( 107 ～109 ) W/CM2  that it can heat, melt, evaporate any metals rapidly for various processing, According to the technique needs, electron beam can be deflected steadily or alternately by deflection coils.