A technique for designing systems of electronic heating of cathodes of welding electron guns

A complex method for analyzing the processes in the systems of indirect cathode heating for electron- beam welding guns is proposed. The necessity of considering the electron-beam formation process in a cathode assembly with predetermined geometric characteristics is justified for calculating the distribution of the heat-flux density over the main-cathode surface. The typical distribution of the heat-flux density over the surface of the main cathode, which is heated via electron bombardment using a spiral wire heater, is analyzed. A method for calculating the temperature distribution over the structural elements of a typical cathode assembly is described, and the calculation results are analyzed. The influence of the nonuniformity of the electronbeam- current density distribution over the heated surface of the main cathode and the heat dissipation on the temperature and emission-current-density distributions on the working surface of the main cathode is considered. The advantages of the proposed method in comparison with existing idealized mathematical models and its suitability for solving problems of designing various electron guns are demonstrated.