Beam focusing versus beam current in electron beam welding

Results are presented of experimental investigation into dependence of the degree of correction of the focusing coil current to maintain constant focusing at changes of the beam current under conditions of real welding. The 12Kh18N10T steel has been used as being welded material. The current for a ''sharp'' focusing is shown to decrease with growth of the electron beam current in the 50-300 mA range. Its least change is observed at elevated accelerating voltages and minimun working distances