GB759593A - Improvements in or relating to the production of mould liners - Google Patents

Abstract

759,593. Coating and lining moulds; casting. BRENNAN, J. B. Nov. 18, 1952, No. 29120/52. Class 83 (1). [Also in Group V] A liner for a surface on or against which molten material is to be cast is made by applying, e.g. by dip or spray 11, Fig. 4, a liquid suspension 7 of heat-resisting fibres, e.g. asbestos or glass fibres, to one face of a porous backing 8, and subjecting the opposite face of the backing to sub-atmospheric pressure to withdraw the moisture and compact the layer against the backing. The suspension may consist of plaster of Paris and water in addition to the fibres, and the liner may be coated with a filler, e.g. carbon, graphite, plaster of Paris or zirconium oxide. The liner may be used in a mould of porous material, e.g. carbon or tungsten carbide, or may be made on the mould. In one embodiment for continuous casting, interconnected mould-halves 21, 23, Fig. 6, form two endless chains, corresponding halves being joined together for part of their travel, to first receive the liquid suspension from pipe 25. At the next stage, the mould enters a vacuumchamber 28 and may be rotated, and a third heating stage may be provided. Molten casting-material from pipe 26 is supplied to the mould at the fourth stage and finally the casting and liner are stripped. In an embodiment for continuously casting strip or sheet metal, a rotating drum 33, Fig. 7, lined with a preformed liner 35 receives molten metal 31 from an electrically-heated crucible 30. The strip is cooled by device 41 and passes with the liner on to reel 37. Alternatively, the liner may be formed on the drum by spraying or passing the drum through a suspension and evacuating the interior of the drum.