Abstract: An oxygen blowing lance capable of directing oxygen jet streams onto a molten metal in an electric furnace, the lance being insertable into an electric furnace through a sidewall working port, the lance being positionable above the molten metal in the electric furnace. The lance includes a horizontal segment and an angled segment, the angled segment being positioned on the distal portion of the horizontal segment and being inclined relative to the horizontal segment. The lance also includes a tip, the tip being positioned on the distal portion of the angled segment, with the distal portion of the tip being directed toward the molten metal. The horizontal segment, the angled segment and the tip define an oxygen flow channel and a cooling water flow channel. The oxygen flow channel extends substantially the length of the lance, and the cooling water flow channel surrounds the oxygen flow channel.

Abstract: According to the present invention, there is provided a direct current electric furnace for melting metal capable of melting scraps rapidly and also capable of diminishing cold and hot spots formed on the furnace wall, wherein the direct current electric furnace is provided with a single top electrode, a plurality of furnace bottom electrodes, or a plurality of electrode units obtained by dividing a multitude of furnace bottom electrodes of a small diameter into plural units, and electric current controlling thyristor circuits for controlling each individually electric currents flowing through the plural furnace bottom electrodes or electrode units. The electric current controlling thyristor circuits may be substituted by thyristor circuits for controlling electric currents for each of plural groups obtained by dividing the above plural furnace bottom electrodes or the above many furnace bottom electrodes or the above plural electrode units into the plural groups.

Abstract: A furnace bottom structure of a direct current electric furnace has at least one furnace bottom electrode and at least one gas injection tuyere provided in the furnace bottom refractory of the direct current electric furnace. Preferably, the furnace bottom electrodes and the gas injection tuyere are embedded in a substantially cylindrical refractory body with downwardly diverging tapered upper portion. The refractory body, the furnace bottom electrodes and the gas injection tuyere form an integral furnace bottom block which is detachably attached to the bottom of the electric furnace so as to close a bottom opening of the furnace.

Abstract: A method and apparatus for vacuum degassing blows gas into molten metal so as to form a substantially uniformly distributed bubble over the path area defined by an induction pipe. In order to achieve this, discharge nozzles are separated into at least two groups. The pressures of the gases discharged through the discharge nozzles in different groups are controlled independently of the other so that gas blown through a first group of nozzles forms bubbles at around the central portion of the induction pipe and the pressure of the gas blown through the other group of nozzles is adjusted for forming the bubbles in the vicinity of the periphery of the induction pipe.

Abstract: A lance for blow-refinement in a converter comprises a primary nozzle generating a high-velocity, high-pressure primary oxygen jet, and an auxiliary nozzle generating an auxiliary oxygen jet. The auxiliary oxygen jet formed by the auxiliary nozzle has a velocity lower than the speed of sound. The auxiliary nozzle is configured so as to impede but not prevent oxygen flow therethrough. In the preferred construction, deceleration of gas-metal reaction induced by the oxygen jet.