Abstract: A plug comprises a refractory body having a plurality of gas passgeways through which gas is blown into a refining apparatus. Each gas passageway may be defined by at least two metal tubes which are longitudinally spaced apart from each other. Alternatively, each gas passageway may be at least partly defined by an electrically insulating tube. The plug may alternatively have a plurality of gas passageways each having a bare refractory wall, while the body is reinforced with nonconductive mineral fibers, or metal wires which do not continuously extend throughout the plug. The plug may further be provided with a plurality of elongated holes extending in parallel to the gas passgeways from the inner surface of the body facing the interior of the refining apparatus to an intermediate portion thereof.

Abstract: A method for continuously pouring molten metal in an initially substantially unfilled tundish having a channel-type inductor having a channel opening into the bottom portion of the tundish, is done by starting the pourings and the continuous sequential steps of applying power to the inductor when its channel is first covered by the poured metal to form a melt level and the static pressure of the metal is low and while increasing the power rapidly so as to cause incipient pinching in the channel and then momentarily rapidly reducing the power so as to prevent pinching; as the metal level further increases so that the metal's static pressure further increases, again increasing the power rapidly so as to again cause incipient pinching in the channel and then again momentarily rapidly reducing the power so as to prevent pinching; and continuing these sequential steps until the tundish is filled.

Abstract: Workpieces are heat treated as they are advanced through and tumbled within a rotary retort. The retort is heated by electrical current which is inductively induced by coils disposed in surrounding relationship with the retort. A flared distributor on the exit end of the retort causes the workpiece to dribble continuously out of the retort.