Abstract: A blowing lance for treating molten metals which are situated in vacuum-treatment vessels, in particular steel in RH vessels, having a central pipe and an encasing pipe which is arranged coaxially with respect to the central pipe and can be cooled by a cooling medium. The central pipe and the encasing pipe are connected to supply lines, which in turn can be connected to an oxygen station, a fuel-gas station and an inert-gas station and to a solids-feed device. In this lance, the cooled encasing pipe is arranged at a distance from the central pipe over its entire length. The free annular area (AR) between the two pipes satisfying the following statement AR=0.8 to 1.2×AZ where AZ=free cross-sectional area of the central pipe. The end of the central pipe is designed in the form of a Laval nozzle. The nozzle opening of the central pipe is being arranged at a distance (a) inside the encasing tube, where a=0.5 to 0.8×d where d=clear diameter of the central pipe.

Abstract: The invention relates to a process for decarburizing a steel melt in a closed metallurgical vessel that is connected to a vacuum unit which includes reducing pressure in the vessel to below 100 mbar, introducing replenishment oxygen to implement the removal of carbon, introducing a predetermined additional amount of oxygen, and introducing a combustible metallic substance with the additional amount of oxygen. The invention also relates to an apparatus for performing the above process including the closable vessel, measurement elements for determining melt temperature and pressure, and a controller for controlling the amount of additional oxygen and combustible metallic substance in response to the melt temperature and pressure.

Abstract: A process and a device for introducing gases into a metal melt contained in metallurgical vessels via ducts arranged in the refractory lining of the vessel. In order to permit deeper penetration of the jet of gas and better mixing with the melt, an oscillating jet of gas is produced and introduced into the melt. For this purpose, several acoustic generators with which the gas is brought into contact with the melt are provided in the device.

Abstract: The invention relates to a process and a device for blowing oxygen over a metal melt under a vacuum. The oxygen is to be applied over a large surface with a large intermediate phase area while avoiding overcooling in the metal bath by simple, easily maintained structural means. The flow of oxygen in the lance is accelerated and compressed into plug-shaped oxygen pulses, which leave the lance in succession and which form an oxygen bell over the vacuum above the metal melt, having an oxygen casing and an oxygen core, the core moving at a speed similar to that of the casing. At the base of the wall 41 of the blowing lance 40 there is an annular nozzle 42. At a distance behind the annular nozzle 42 in the direction of flow of the oxygen there is a blind tube 44 forming a fan-shaped compartment 43. Between the bottom 46 of the blind tube 44 and the head of the blowing lance 40 there is a pre-nozzle chamber 48 and in the head of the blowing lance 40 there is at least one base nozzle 50 directed toward the melt.

Abstract: This invention relates to a degassing vessel for the vacuum treatment of liquid steel, consisting of a lower, middle and upper part. To protect the heater rod, which in the degassing vessel is oriented at a right angle to the center axis, the invention essentially proposes that the middle part has a cylindrical shape with the same radius as the lower part, that in the vicinity of the connection to the upper part there is a flat gas guide surface parallel to the heater rod and at an angle to the cylindrical jacket, and that finally the jacket of the upper part connected to the middle part has the shape of a half-tube, which is closed by a flat surface oriented parallel to the center axis.

Abstract: A plant for secondary metallurgical processing of molten steel, having a melting apparatus and a continuous casting apparatus, a first station and a second station each having an associated evacuatable container for the molten steel, an oxygen feed device and an additive feed device. Each container receives a casting ladle, and has a vacuum-tight cover to provide a seal. A moderate vacuum device, e.g. a water ring pump and a high vacuum device, e.g. a water ring pump and a steam jet are provided, and are connected to the container via a device for selectively connecting the moderate vacuum device and the high vacuum device to the containers.