Method for operating a double-strip continuous casting mould for die-casting steel and a casting nozzle interacting with a double-strip continuous casting mould for carrying out the method

摘要

When casting steel under pressure, care must be taken that the sealing gap between the moving mould walls of the double-strip continuous casting mould and the fixed mouthpiece of the casting nozzle prevents the escape of molten steel counter to the casting direction at all times. In order to relieve the said seal of load in the region of the mouthpiece 2b of the casting nozzle in order to make the start-up process easier, a mode of operation is proposed in which the molten steel entering the mould space 4 as a free jet 16 first of all forms a molten pool 17 with a molten metal level 17% below the outlet 2> of the casting nozzle. Only after a run-in phase of several minutes is the ratio between the feed flow rate and the outlet flow rate moving at the casting speed altered in such a way that the molten steel finally fills the mould space completely. The associated casting nozzle 2 is characterised in that its mouthpiece 2b, including the sealing surface 2% interacting with the mould walls is composed of amorphous silica (SiO2) and that its smallest bore cross-section, which forms a restriction 15 that produces a free jet 16, lies in the mouthpiece. <IMAGE>