GB1305643A - - Google Patents

Abstract

1305643 Continuous casting MONSANTO CO 10 April 1970 [11 April 1969] 17187/70 Heading B3F A crucible assembly 13, Fig. 1, or 70, Fig. 4, for spinning a melt having a viscosity no greater than unity, e.g. Cu, Fe or steel, has a base-plate 14 or other member 65, 67 with an extrusion opening 19 or 66 coaxially aligned with an aperture in a shelf 11 or 62 which is of material such as pyrolytic boron nitride or graphite which is thermally anisotropic and is more conductive in planes 22 or 77 perpendicular to the direction of extrusion so that there is even heat distribution to the base-plate 14 or member 65 from the periphery of the shelf 11 or 62. The anisotropic shelf (32) may be separated from the crucible base (35) by a graphite or beryllia member (33) which, like a member 68 in Fig. 4, reduces immediate contact of melt and film-forming gas into which it is spun. The extrusion opening 19 or 66 may be the spinning orifice or receive an insert defining the orifice. There may be several openings 19 in the base-- plate 14. An induction coil 17 or 74 heats the periphery of the anisotropic shelf 11 or 62 and the crucible 13 or 70 (by way of a susceptor 12 or 69) and melts the spinning charge in it. The crucible is of alumina, beryllia or zirconia and the contacting surfaces of a base cover-plate 15 or base 71 and a wall member 16 or 72 are lapped mating surfaces. For greater control of melt temperature, the crucible may have an upper reservoir (42. 43). There may be two anisotropic shelves 61, 62. To increase the heating of the shelf aperture, the pitch of the induction coil is increased and to restrict the heat flow to the upper portion of the shelf, the inner coil of the water-cooled inductor 74 is mounted on and in electrical contact with a copper support 76 gapped to prevent short circuiting of the inner coil. The upper and lower parts of the inductor may be separately powered. There may be an annular slot (51) in the bottom of the shelf (32) to restrict heat transfer in the lower shelf portion. Reference has been directed by the Comptroller to Specifications 1,153,577 and 1,197,972.