GB854176A - Improvements in or relating to methods and apparatus for melting ductile metals - Google Patents

Abstract

854,176. Electric heating. HERAEUS G.m.b.H., W. C. March 25, 1957, No. 9738/57. Class 39(3). In a method of melting highly chemically reactive ductile metals or alloys thereof, which have a high melting point, in a vacuum or an inert gas atmosphere, an electrode of the metal is produced by feeding a rod of the metal, which has had a preliminary chemical purification, into an induction heating zone to melt the rod therein; this melt is then solidified to form the electrode which is then used as a consumable electrode for arc melting of the metal. In Fig. 1 metallic material in granular &c. form in conveyed from a hopper 18 to a shoot 20, and a motor driven press 22 with a stamp 21 forms the material into a rod 2 which passes through a tube 32 and pressure stage chambers 23-25 to an induction melting chamber 46. Pump units 26-31 and 33, 34 are connected to the chambers and effect degasification of the rod and produce in the chambers 23-25 a gradual pressure drop down to a high vacuum in the chamber 46. The lower end of the rod is melted as it passes through an induction coil 5 and the melt falls into a water cooled funnel 7 and is formed into a rod 8 which is fed by rollers 9, 10 through a chamber 36 to a melting crucible 12. Pumps 37, 38 maintain the chamber 36 and crucible at a high vacuum and degasify the metal. An electric arc is established between the end 11 of the rod and the solidified metal 13 on the crucible base 14. A cooling jacket 39 is provided about the crucible and as the rod melts the crucible base is lowered by means of a shaft 17 lowered by a motor 15 and gearing 16. Rollers 9 and 10 provide one current connection, the other being shown at 41. The base is cooled by fluid fed through lines 42a, 42b. An insert gas is fed into the chamber 24 from a cylinder 43. In a modification a number of prefabricated rods are housed in a container at the top of the installation and are introduced into a chamber, to which may be fed a protective gas, and the rods are welded together by opposed electrodes. The welded rod is then fed through a single pressure stage chamber to an induction heating chamber &c. as in Fig. 1.