Modelling of Heat Source Dynamics in Electron Beam Welding

Electron beam welding is one of the important fabrication processes for fusion reactor components subsystems. This weld process offers superior advantages over other techniques by producing very low distortions, high aspect ratios, lower stresses and deep penetration with single pass. A complete understanding of the electron beam welding with heat flux and temperature profiles during the beam metal interaction is still not completely understood. In addition, the formation of the weld bead geometry in weld pool is fully governed by the plasma keyhole kinetics and their control over the depth is due to the combined gaseous (vapor) and liquid molten material during high speed electron beam welding process. The weld defects caused by the process are completely dependent on the shape and movement of the keyhole plasma during the electron beam interaction within the material. The present investigations are focused on understanding the keyhole effects on the weld bead formation with various heat input parameters like flux and power density. Corresponding analytical estimations based on point and line source models have been attempted to estimate the temperature profile during the keyhole formation. The conductive and radioactive regimes are considered for the temperature profile estimation of the molten pool cavity over the penetration depths. The power density distribution over the depth of the materials for stainless steel is attempted and temperature and heat flux distributions are evaluated. Analytical results are presented and potential applications with electron beam welding in the fusion reactor are highlighted.