Electron Beam Melting of Sponge Titanium

Abstract

Fundamental investigations were done on electron beam melting of sponge titanium by using 80 kW electron beam melting furnace. Results obtained are as follows:
(1) To increase the melting yield of titanium in electron beam melting of sponge titanium, it is important to recover splashed metal and to prevent the evaporation of molten metal during melting. It is possible to collect the splashed metal by installation of water-cooled copper wall around the hearth and to decrease the evaporation loss of titanium by keeping the surface temperature of molten metal just above the melting temperature of titanium without local heating.
(2) Specific power consumption of drip melting of pressed sponge titanium bar and hearth melting of sponge titanium are approximately 0.9 kWh/kg-Ti and 0.50.7 kWh/kg-Ti respectively.
(3) Ratios of the heat conducted to water-cooled mould in the drip melting and to water-cooled hearth in the hearth melting to the electron beam input power are 5065% and 6065% respectively. Overall heat transfer coefficient between molten metal and hearth cooling water is about 0.010.03 cal/cm²·s·K.