Thermal Processes in Electron-Beam Treatment of Metals

An amended quasi-stationary model of heat transfer in a metallic ingot hardening in a water-cooled crucible after electron-beam melting and refining of the metal is suggested. The processes of heat transfer and heat flows through different interfaces are considered for aluminum and tantalum under the assumption of three mechanisms of heat transfer. The model allows for the temperature dependences of the thermal conductivity and specific heat capacity. Experimental results are used for estimating the distribution of energy in beam heating of the metal and the losses of heat to radiation and evaporation from the upper surface of the ingot. Data on the shape of the hardening front, on the geometry of the molten zone, on the heat flow at various treatment parameters (electron beam power, casting rate, etc.) are obtained and discussed.