STRAIGHT BARREL TYPE VACUUM REFINING DEVICE AND METHOD FOR USE THE SAME

• US 20150240323A1
• Filed: 08/20/2013
• Published: 08/27/2015
• Est. Priority Date: 08/24/2012
• Status: Active Grant

• Current Assignee: Magang (Group) Holding Co.,Ltd. (China BaoWu Steel Group Corp. Ltd.), Maanshan Iron & Steel Company Limited
• Original Assignee: Magang (Group) Holding Co.,Ltd. (China BaoWu Steel Group Corp. Ltd.), Maanshan Iron & Steel Company Limited
• Inventors: Wu, Liping, Shen, Chang, Hu, Yuchang, Pan, Yuanwang, Pu, Shaomin, Wang, Yong, Xie, Yangguo
• Granted Patent: US 9,809,868 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: C21C 7/064 Dephosphorising; Desulfurising
• CPC Class Codes: C21C 7/068 Decarburising
• CPC Class Codes: C21C 7/072 Treatment with gases C21C7/06, C21C7/064, C21C7/068 take precedence
• CPC Class Codes: C21C 7/10 Handling in a vacuum

Abstract

Provided is a straight barrel type vacuum refining device comprising a vacuum chamber and a snorkel; during the vacuum refining the snorkel is inserted into the molten steel of the steel ladle, it is characterized in that, disposing a circulating tube being on the circumference of said snorkel, and blowing argon gas into the snorkel through the nozzles on an inner wall of a circulating tube; said circulating tubes are disposed in layers, the nozzles on the circulating tubes in the same layer are individually controlled as 2-6 in one group; disposing an eccentric gas permeable brick at the bottom of said steel ladle, and blowing argon gas into the steel ladle through the eccentric gas permeable brick, driving a circulating flow molten steel between the steel ladle and the vacuum chamber by using different blowing flow rate combinations of a steel ladle bottom blowing and each individually controlled unit of the circulating tube blowing system.

Claims

1. A straight barrel type vacuum refining device comprising a vacuum chamber and a snorkel, during the vacuum refining the snorkel is inserted into a molten steel of a steel ladle, characterized in that, disposing a circulating tube in a circumference of said snorkel dispose, and blowing argon gas into the snorkel through the nozzles on the inner wall of the circulating tube;

disposing said circulating tube in different layers, and individually controlling the nozzles on the circulating tube of the same layer;

disposing an eccentric gas permeable brick at the bottom of said steel ladle, and blowing argon gas into the steel ladle through the eccentric gas permeable brick, and driving the circulating flow of the molten steel between the steel ladle and the vacuum chamber by using different blowing flow rate combinations of steel ladle bottom blowing and each individually controlled unit of the circulating tube blowing system.

2. The straight barrel type vacuum refining device according to claim 1, characterized in that, disposing said circulating tubes in one layer, distributing the nozzles on the circulating tube at equal central angle, the central angle between nozzles being 10°

-30°

;

or, distributing the nozzles on the circulating tube at equal distance, and the number of the nozzle being 8-30.

3. The straight barrel type vacuum refining device according to claim 1, characterized in that, disposing said circulating tubes in two layers, distributing the nozzles on each of the circulating tube at equal distance, the number of the nozzles in each layer being 6-15, and the nozzles in the upper and lower layers being cross arranged;

the distance from the lowest layer of said circulating tube to the bottom of the snorkel being 100 mm-500 mm.

4. The straight barrel type vacuum refining device according to claim 1, characterized in that, disposing said circulating tubes in three layers, distributing the nozzles on each of the circulating tube at equal distance, the number of the nozzles in each layer being 6-12, the nozzles in adjacent layers being cross arranged, and distributing the layers at equal distance, the distance being 150 mm-400 mm;

the distance from the lowest layer of said circulating tube to the bottom of the snorkel being 100 mm-500 mm.

5. The straight barrel type vacuum refining device according to claim 1, characterized in that, the distance between the outer diameter of said snorkel and the inner diameter of said steel ladle being 100 mm-400 mm.

6. The straight barrel type vacuum refining device according to claim 1, characterized in that, the cross-sectional shape of said snorkel being roughly circular, consisting of two parts of a large circular arc and a small circular arc, the radius of the large circular arc being same as the vacuum chamber, the radius of the small circular arc being greater than vacuum chamber, and the ration of the radius of the large circular arc and the small circular arc being 1:

1-∞

.

7. An operation method of the straight barrel type vacuum refining device according to claim 1, characterized in that, the vacuum refining process adopting a combined blown mode of a steel ladle bottom eccentric gas permeable brick and a snorkel circulating tube;

during decarburization, the bottom blowing and the circulating tube on the same side as the bottom blowing being strong blowing, the circulating tube on the other side being weak blowing;

during desulfurization, the bottom blowing being strong blowing, and the circulating tube around the snorkel being all weak blowing;

in later period of the refining, adjusting the circulating tube gas quantity and the bottom blowing quantity to small, and controlling the molten steel clean circle not to be involved in the vacuum chamber surface slag, meanwhile promoting the inclusions in the steel to collide and float and to be absorbed by the surface slag.

8. An operation method of the straight barrel type vacuum refining device according to claim 1, characterized in that, when clogging occurs in the vacuum refining process, closing the steel ladle bottom blowing or the steel ladle bottom blowing as required, the refining method is as follow:

(1) during decarburization, one side of the circulating tube uses large quantity blowing, and the corresponding the other side uses small quantity blowing, these two semi-circumference regions form an ascending pipe and a descending pipe similar to RH, to achieve the molten steel rising on one side of the strong blowing and declining on the side of the weak blowing, driving the circulating flow of the molten steel in the vacuum chamber and the steel ladle, meanwhile because one side is strong blowing and the other side is weak blowing, the steel ladle slag on the vacuum chamber molten steel face is compressed to the side of the weak blowing, ensuring the exposed face of the molten steel in the vacuum chamber being sufficiently large to achieve the purpose of rapid deep decarburization;

(2) during desulfurization, the nozzles are all strong blowing, driving the molten steel rising around the snorkel and declining from the central region, and achieving the purpose of deep desulfurization of the molten steel by complete mixing of the steel ladle slag and the molten steel under a vacuum condition;

(3) in a later period of the refining, altering the circulating tube blowing quantity to large on one side and very small on the other side, and controlling the molten steel circle not to be involved in the vacuum chamber surface slag, meanwhile promoting the inclusions in the steel to collide and float and to be absorbed by the surface slag.

9. The straight barrel type vacuum refining device according to claim 5, characterized in that, the cross-sectional shape of said snorkel being roughly circular, consisting of two parts of a large circular arc and a small circular arc, the radius of the large circular arc being same as the vacuum chamber, the radius of the small circular arc being greater than vacuum chamber, and the ration of the radius of the large circular arc and the small circular arc being 1:

1-∞

.