Abstract: A nozzle is provided having an elongated conduit extending therethrough for delivering molten metal below the surface of a pool of molten material. The nozzle includes facilities for passing a fluid medium, e.g., argon, through its wall members transverse to the direction of molten metal flow into the elongated conduit to retard the accumulation of undesirable formations, e.g., metal oxides, on the inner wall surfaces of the conduit during molten metal flow. In a first embodiment, gas permeable wall members define portions of the conduit through which the fluid medium percolates. In a second embodiment, a plurality of small ports are provided in the wall members defining the conduit through which the fluid medium is emitted in the conduit. Preferably, the nozzle also includes a base portion that directs the molten metal flow in an upwardly direction and which has facilities for retarding the accumulation of undesirable formations thereon.