| 摘要 |
The invention relates to a process for manufacturing nozzles with magnesite insert applicable to the continuous casting installations, particularly used to equip the continuous flow distributors. According to the invention, the process comprises the preparation of a mixture containing sintered magnesite with the grain size from 1 ... 0.5 mm to 0.5 ... 0.09 mm in a proportion of 65 %, wetted with 4 ... 6 % magnesium sulphate solution having the minimum density of 1.20 g/cm 3 or dextrine solution having the density of 1.15 g/cm 3, whereto fine magnesite with the grain size less than 0.09 mm in a proportion of 35 % is added, then the mixture is formed by pressing with minimum 1000 kgf/cm 2 being degassed twice and dried at minimum 180° C, then the nozzle is burnt at minimum 1450°C, and the inner insert is burnt at a temperature exceeding 50°C. After having been burnt, only the insert is impregnated with preheated tar inside an enclosure having less than 10 mm Hg vacuum, by applying a pressure of 9.80665 bars, the impregnated inserts being heat treated at 350 ... 400 °C.
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