GB745769A - Improvements in or relating to the treatment of light metals - Google Patents

Abstract

745,769. Refining light metals and alloys. KAISER ALUMINUM & CHEMICAL CORPORATION. Dec. 9, 1953 [Dec. 15, 1952], No. 34301/53. Class 82(1). Molten light metals such as A1 and Al-base alloys are treated prior to casting to provide metal free from or substantially free from gas and other non-metallic impurities by providing a body of molten metal in a receptacle having a moisture containing atmosphere, withdrawing metal in a continuous stream past a source of fluxing material, which fluxing material is introduced into the flowing stream so that substantially only that portion which is being withdrawn from the receptacle is in intimate mixture with the fluxing material. Fig. 1 shows a furnace chamber or receptacle 1 containing molten metal 2. Molten metal flows continuously through top hole 3 below the level of the metal in the receptacle. Adjacent the top hole a refractory tube 7 is positioned to introduce a fluxing gas such as Cl or N to bubble up through the flowing metal and is confined by side walls 11 and front wall 12 to form a protective cover over the metal surface. Metal leaving the receptacle is under-poured into a conveying trough 21, the rate of flow being controlled by. a valve 19. This trough is provided with a cover 23 and a dry gas atmosphere may be maintained in the trough to prevent contamination of the flowing metal. In the modification shown in Fig. 7 metal flows from the receptacle 1 into an adjoining chamber in which it is treated with gas passed through tubes 65. Metal leaves the second chamber through tap hole 69 and enters the conveying trough at substantially the same level the flow being controlled by valve 70. Among the alloys which may be treated in this way are those of composition Cu 3À8-4À9 per cent, Si up to 0À5 per cent, Fe up to 0À5 per cent, Mn 0À3-0À9 per cent, Mg 1À2-1À8 per cent, Zn up to 0À1 per cent, Cr up to 0À1 per cent, A1 the balance and Cu 1À2-2À0 per cent, Si up to 0À5 per cent, Fe up to 0À7 per cent, Mn up to 0À3 per cent, Mg 2À1-2À9 per cent, Zn 5À6-6À1 per cent, Cr. 0À18-0À4 per cent, Ti up to 0À2 per cent, Al the balance. U.S.A. Specification 2,301,027 is referred to.