| 摘要 |
PURPOSE:To prevent the generation of porosities and wormhole like beads in performing electron beam welding by changing the cross sectional shape of an electron beam from a circular shape to an elliptical shape at prescribed periods. CONSTITUTION:In electron beam welding, a deflection coil 2 for an electron beam 3 is provided in the lower part of a focusing coil 1 for the beam 3, and a transmitter 4 and an amplifier 5 are installed to the connection thereof so as to form Kapp's magnetic field when electricity is conducted to this coil 2. When the electrical circuit for forming the Kapp's magnetic field is held open, the cross sectional shape of the beam 3 is circular, and if the circuit s closed, the beam deforms to an elliptical shape. In this way, the cross sectional shape of the electron beam is changed periodically, by which the disturbance and pores in the flow of the molten metal in the molten pool in welding base metals are agitated and reheated, whereby the generation of porosites and wormhole beads is prevented. |
