Pressures and Consumable-electrode Arcs.
J Vacuum Sci and Technol 1971 8(6):Vm5-vm12
An investigation of arc zone pressure during consumable-electrode vacuum-arc remelting (cevar) experiments has shown that pressure differences and gradients within furnaces are functions of pressure itself, electrode composition, and the degree of arc-zone confinement. There is evidence also that some previously puzzling contrasts in arc-furnace behavior may be explainable on the basis that two pressure dependent forms of electrical discharge operate with distinct potentials. The lower voltage form tends to become unstable at pressures <0.5 Torr and behaves best at pressures >1 torr. The higher voltage form seems to be most stable at pressures <0.1 Torr. For continuous operation and maximum versatility, a cevar furnace should be able to accommodate both discharge forms by providing for variability of vacuum conditions.
J. Vacuum Sci. and Technol., V. 8, No. 6, November-December 1971, PP. Vm5-vm12