PROCESS FOR A VACUUM DECARBONIZATION AND DEGASIFICATION OF STAINLESS STEELS

摘要

The invention relates to a vacuum decarbonization and degasification of stainless steels, used in ferrous metallurgy. According to the invention, the process consists, in a first step, in regulating the argon flow for removing the slag from the metal bath on a surface of 0.2 ... 0.3 square meters, followed by the emptying of the enclosure down to a pressure ranging from 0.53 x 104 to 0.8 x104 N/square meter. The oxygen blast begins with a flow ranging from 5.8x10-6 to 7x10-6 Nmc/kgxs, for the initiation of the decarbonization reaction, watching that the pressure inside the enclosure is maintained between 2x104 and 2.6x104 N/square meter during the oxygen blast process. The initial argon flow is doubled to a carbon percentage of the metal bath ranging between 0.10 and 0.15 %, continuing the oxygen blast till the pressure inside the enclosure goes down to values ranging between 0.13 x 104 and 0.53x104 N/ square meter for ferrite stainless steels or the doubling of the initial argon flow is combined with the increase of oxygen flow to values ranging between 8.3 x10-6 and 9.9x10-6 Nmc/kgxs, till the pressure inside the enclosure goes down to a pressure ranging between 0.8x104 and 1.33x104 N/square meter, when the oxygen blast stops, the argon pressure increases up to 3 times the initial value and the pressure inside the enclosure goes down to a vacuum ranging between 0.1 to 0.2 x103 N/square meter, this pressure being maintained for 900 ... 1200 s for all marks of stainless steels.