GB1237115A - Apparatus for production of castings - Google Patents

Abstract

1,237,115. Casting processes. INSTITUT ELEKTROSVARKI IMENI E.O. PATONA. 28 June, 1968, No. 30918/68. Heading B3F. [Also in Divisions C7 and H5] An apparatus for refining and casting metals comprises a cooled mould 2 connected to an electrical supply 17 and a chamber 1 above the mould having a plurality of plasma torches 4 which are connected to the electrical supply and provide a plasma for melting a metal billet or charge. Metal charge pieces are supplied to the mould by a hopper 9. When a billet 7 is being melted, the billet may also be connected to the electrical supply. When starting the apparatus a pool of molten metal is first formed in the mould, then the billet and the mould stool 6 are moved downward and cooling of the mould is commenced. The plasma torches are arranged around the billet so as to impart a rotatory movement of the molten metal in the mould, this ensuring even solidification of the metal. The atmosphere and pressure in the chamber 1 may be controlled. Filters, chemical purification apparatus 16 and pumps 15 are provided to recondition and recirculate the gases in the chamber. Unkilled. metals (iron, nickel and alloys thereof) may be reduced by supplying hydrogen or a hydrogen/argon mixture to the plasma. Alloys which form oxide scabs when poured in air or steels containing non-metallic inclusions may be refined by adding a layer of slag to the top of the mould. Nitrogen containing steels may be remelted or saturated with nitrogen by operating the plasma torches with argon/ nitrogen or pure nitrogen. Heating by electricity.-The melting of the billet and the falling of drops of the melt therefrom may be controlled by interrupting either the supply of electricity or plasma forming gas to the plasma torches.