1.Dehydrogenation When the vacuum degree is ≤ 133Pa, the hydrogen content in the molten steel [H] is ≤ 1.5 ppm. Due to the fact that the hydrogen content in the molten steel during vacuum treatment is related to factors such as operating process,
steel grade, state of various raw materials added to the furnace, and argon stirring state, in order to ensure that the hydrogen content in the molten steel is ≤ 1.5 ppm and improve the dehydrogenation rate, the working vacuum degree
of the vacuum system is determined to be below 67Pa, fully ensuring the requirements of the dehydrogenation process.
2. Denitrification The relationship between the saturation concentration of hydrogen and nitrogen in molten steel and the partial pressure
of hydrogen and nitrogen above the melt.However, the nitrogen content in molten steel is closely related to the content
of alloy elements in the steel, making it difficult to remove nitrogen. Therefore, try to reduce the nitrogen content in the steel before VD treatment and extend the VD treatment time.
3. Desulfurization The content of sulfur in steel is also related to oxygen and often maintains a constant proportion, so the deoxidation process of vacuum treatment is also a desulfurization process. In order to obtain steel grades with extremely low
sulfur content, some elements with strong affinity for sulfur were used as desulfurizers for desulfurization.
4. Argon stirring Argon gas is blown into the ladle through the argon blowing port of the breathable brick at the bottom of the ladle to
stir the molten steel, causing it to circulate within the ladle. Its function is to create more favorable conditions for the physical and chemical reactions of the molten steel inside the ladle.In order to ensure the effective and smooth
operation of the entire refining argon stirring process, each vacuum tank in this design adopts an independent argon
flow rate adjustment system, and the argon flow rate is controlled by a dedicated mass flow control module, thereby achieving precise automatic adjustment of argon gas volume.
