Straight barrel type vacuum refining device and method for use the same

A method of operating a vacuum refining device, wherein the vacuum refining device comprises:

• a vacuum chamber;
• a snorkel connected to the vacuum chamber, wherein the snorkel is tubular in shape;
• a steel ladle adapted to hold molten steel during vacuum refining, wherein the snorkel is adapted to be inserted into the molten steel in a steel ladle during vacuum refining;
• a first circulating tube disposed about an inner circumference of said snorkel and adapted to blow a first argon gas into the molten steel through a plurality of nozzles disposed thereon, wherein a flow rate of the first argon gas in each of the plurality of nozzles on the circulating tube is individually controllable,
• a gas permeable brick eccentrically placed in a bottom of the steel ladle, wherein, during vacuum refining, a second argon gas blows into the steel ladle through the gas permeable brick to circulate the molten steel between the steel ladle and the vacuum chamber,
• the method comprising:
• inserting the snorkel into the molten steel in the steel ladle;
• blowing a first argon gas into the molten steel through the circulating tubes through the plurality of nozzles disposed thereon;
• blowing a second argon gas into the molten steel through the gas permeable brick in the bottom of the steel ladle,
• wherein, during decarburization, the blowing through the gas permeable brick and the blowing through the circulating tubes on the same side as the gas permeable brick is strong blowing, the blowing through circulating tube on the other side is weak blowing;
• during desulfurization, the bottom blowing through the gas permeable brick is strong blowing, and the blowing through circulating tube around the snorkel is weak blowing;
• and
• after decarburization and desulfurization, lowering the flow rate of the first argon gas through the circulating tubes and the flow rate of the second argon gas through the gas permeable brick.