Induction melting of metals in cold, self-lined crucibles

Claim 2

A process for melting and forming metals which comprises: a. placing an initial solid charge of a metal chosen from the group consisting of iron and nickel base alloys, titanium, zirconium, hafnium and their alloys, together with a slagging material, said material comprising a metallic compound having electrical insulating properties when solid and having a melting point below that of the metal charge, within a metallic crucible open at the top and bottom and of uniform cross-section throughout the length thereof and having sidewalls divided by longitudinal slits into at least two segments, each segment being maintained in electrical isolation from every other segment; b. establishing a pool of molten slag and metal within the crucible by applying an alternating electrical flux supplied by a primary induction coil surrounding an upper portion of the crucible; c. maintaining the temperature within a lower portion of the crucible at a temperature substantially less than that of the upper portion; d. continuously cooling the crucible to form and maintain a frozen slag lining on the interior surfaces of the crucible and filling the longitudinal slit, and e. adding additional solid metal to the molten pool to be melted and assimilated therein.

Claim 3

The process of claim 3 wherein the pool of molten slag and metal within the crucible is established on top of a metallic starting stub positioned within the lower portion of the crucible and wherein the starting stub is withdrawn at a rate substantially equal to the rate of addition of solid metal to the molten pool to continuously form an ingot conforming to the cross-sectional shape of the crucible.

Claim 4

The process of claim 4 wherein the cross-sectional shape of the crucible is circular.

Claim 5

The process of claim 4 wherein the initial metal charge and additional solid metal is chosen from the group consisting of titanium, zirconium, hafnium, and their alloys.

Claim 6

The process of claim 6 wherein the metal is titanium and wherein the Slagging material comprises an alkaline earth metal fluoride.

Claim 7

The process of claim 7 wherein the slagging material comprises calcium fluoride.

Claim 8

The process of claim 6 wherein the melting and forming of a refractory metal is performed in a non-reactive environment.

Claim 9

The process of claim 9 wherein the non-reactive environment comprises a vacuum.

Claim 10

The process of claim 9 wherein the non-reactive environment comprises an inert gas atmosphere.