GB1029966A - Improvements in or relating to the teeming and degassing of molten metal - Google Patents

Abstract

<PICT:1029966/C6-C7/1> Molten metal is teemed into an intermediate receptacle located in a vacuum tank through a pouring arrangement such that the metal forms a divergent stream, the metal collecting as a deep pool the surface of which is exposed to the vacuum. The metal is tapped from the intermediate receptacle without the application of vacuum. Degassing may be aided by the injection of an inert gas into the pool of metal in the intermediate vessel and also by the positioning in that vessel of a flow-interrupting member which collects the incoming stream as a shallow pool and allows it to overflow. In the apparatus shown in Fig. 1, ladle 10 is mounted on vacuum tank 30 within which is located tundish 60, the vessel 30 being made vacuum tight by O-ring seals 40, 43 and 52. Molten metal is discharged from ladle 10 through nozzle 27 and refractory sleeve 97 in radiation shield 90, the nozzle and sleeve being so arranged that the metal falls in a divergent stream into tundish 60 from where, when a suitable depth of metal has been attained, it is tapped into a series of moulds. Stopper rod 74 contains a tube 77 through which inert gas is passed to be discharged through porous disc 78. In the modification of Fig. 2 (not shown) the metal stream is collected in a shallow refractory tray attached to the top of tundish 61 and then overflows therefrom into the main body of metal. This tray may have in its base a porous disc through which inert gas may be admitted; the tundish may also have a screw feeder 125 by means of which alloying additions may be made, preferably after degassing is complete.