# US 9,752,202 B2 · High cleanliness molten steel production method and refining device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,752,202 B2 - Document ID: US9752202B2 - Status: Granted - Kind: B2 - Application number: 14/400,908 - Filed: 2013-05-13 - Published: 2015-05-07 - Granted: 2017-09-05 - Earliest claimed: 2012-05-14 - Assignees: Posco - Applicants: Posco - Inventors: Ja Yong Choi; Seung Min Han; Sun Koo Kim; Hee Ho Lee; Sang Yuel Jung; Young Jong Seo - Web page: https://patentgrep.com/patent/US9752202B2 ## CPC - C21C 7/00: Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00 (treating molten metals during moulding B22D1/00, B22D27/00) - B22D 1/00: Treatment of fused masses in the ladle or the supply runners before casting {(for continuous casting B22D11/10; metallurgical processing, e.g. refining of iron or other metal C21, C22, C25C)} - B22D 11/116: Refining the metal - B22D 11/118: by circulating the metal under, over or around weirs (B22D11/119 takes precedence) - B22D 41/00: Casting melt-holding vessels, e.g. ladles, tundishes, cups or the like (B22D39/00, B22D43/00 take precedence) - B22D 41/08: for bottom pouring (B22D41/14, B22D41/50 take precedence) - C21C 7/0075: {Treating in a ladle furnace, e.g. up-/reheating of molten steel within the ladle} - C21C 7/076: Use of slags or fluxes as treating agents (C21C7/06, C21C7/064, C21C7/068 take precedence) - C21C 7/06: Deoxidising, e.g. killing - Y02P 10/20: Recycling - C21C: PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS - B22D: CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES (shaping of plastics or substances in a plastic state B29C; metallurgical processing, selection of substances to be added to metal C21, C22) - Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS ## Abstract Provided are a method and a refining device for producing molten steel of outstanding cleanliness, and more particularly provides a method and device for refining inclusions by forming droplets from molten steel and dropping same into slag during pre-processing in a continuous casting process in a steel-making process. Also, provided is a method for producing high cleanliness molten steel comprising a molten-steel supply device for supplying molten steel and a molten-steel refining device for containing and refining molten steel poured into the molten-steel supply device, wherein the method comprises: a molten-steel pouring step in which molten steel is poured from the molten-steel supply device into the molten-steel refining device; a droplet-forming step in which the molten steel which has been poured in is formed into droplets in the molten-steel refining device; a slag-pass-through step in which the molten steel which has been formed into droplets is dropped so as to pass through slag; and an inclusion-removing step in which residual inclusions in the molten steel, which has been formed into droplets, are removed while passing through the slag. ## Claims ### Claim 1 A high cleanliness molten steel refining device, comprising: a first container adapted to receive molten steel poured from a molten steel supply device; and a droplet forming device positioned within the first container and comprising a second container comprising: a sidewall separate from any sidewall of the first container; and a droplet forming portion having a plurality of droplet holes for forming molten steel into droplets at a central part of the second container, wherein the first container is a tundish, the droplet forming device is within a tundish body of the tundish, and the droplet forming device is adjacent to a lower region where molten steel is poured, wherein the droplet forming device further comprises a molten steel accommodating portion at a lower portion of a molten steel pouring region in the tundish body to accommodate the molten steel poured from the molten steel supply device and is configured to move the poured-in molten steel to the droplet forming portion via the molten steel accommodating portion, and wherein the droplet forming portion further comprises an opening on an opposite side of a region where the plurality of droplet holes are formed is coupled so that an upper portion of the molten steel accommodating portion is passed through via the opening or located at an upper portion of an outer circumference surface of the molten steel storage space of the molten steel accommodating portion so that an upper portion of the molten steel accommodating portion is passed through via the opening. ### Claim 2 (depends on 1) The device of claim 1, wherein the molten steel accommodating portion is adjacent to an inner side surface and a lower side surface of the tundish body at a lower region of the molten steel pouring region. ### Claim 3 (depends on 2) The device of claim 2, wherein the droplet forming portion is supported by a weir provided in the tundish body. ### Claim 4 (depends on 3) The device of claim 3, wherein a portion of the sidewall of the second container on one side of the droplet forming portion is supported by the weir and a portion of the sidewall of the second container on another side is supported by the molten steel accommodating portion. ### Claim 5 (depends on 3) The device of claim 3, wherein a portion of the sidewall of the second container on the one side of the droplet forming portion is supported by the weir and a portion of the sidewall of the second container on the another side is supported by being coupled to an inner side surface of the tundish body. ### Claim 6 A high cleanliness molten steel refining device, comprising: a first container adapted to receive molten steel poured from a molten steel supply device; and a droplet forming device positioned within the first container and comprising a second container comprising: a sidewall separate from any sidewall of the first container; and a droplet forming portion having a plurality of droplet holes for forming molten steel into droplets at a central part of the second container, wherein the first container is a tundish, wherein the droplet forming device is within a tundish body of the tundish, and wherein the droplet forming device is adjacent to a lower region where molten steel is poured, wherein the droplet forming device further comprises a molten steel accommodating portion at a lower portion of a molten steel pouring region in the tundish body to accommodate the molten steel poured from the molten steel supply device and is configured to move the poured-in molten steel to the droplet forming portion via the molten steel accommodating portion, wherein a portion of the sidewall of the second container adjacent to the molten steel accommodating portion is formed lower than a portion of the sidewall on another side. ### Claim 7 (depends on 1) The device of claim 1, wherein the droplet hole is 6.5 mm or less in diameter. ### Claim 8 A high cleanliness molten steel refining device comprising: a tundish including a tundish body and a tundish cover for covering a side of the tundish body; and a droplet forming device comprising: a molten steel accommodating portion formed by blocking the tundish body with a first weir; and a droplet forming portion provided adjacent to the molten steel accommodating portion in the tundish body comprising: a container comprising: a sidewall separate from any sidewall of the tundish; and a droplet forming portion having a plurality of droplet holes for forming molten steel into droplets at a central part of the container. ### Claim 9 (depends on 8) The device of claim 8, wherein the molten steel accommodating portion is a space between the first weir and an inner side wall of the tundish body. ### Claim 10 (depends on 8) The device of claim 8, wherein the droplet forming portion and the molten steel accommodating portion are on opposite sides of the first weir. ### Claim 11 (depends on 8) The device of claim 8, further comprising a second weir supported on an inner sidewall of the tundish body and supporting the droplet forming portion. ### Claim 12 (depends on 11) The device of claim 11, wherein the droplet forming portion is supported by the first weir and the second weir in a space between the first weir and the second weir. ### Claim 13 (depends on 12) The device of claim 12, wherein a lower portion of the second weir is open. ### Claim 14 (depends on 8) The device of claim 8, wherein the molten steel, overflown from the molten steel accommodating portion, is transferred to the droplet forming portion. ### Claim 15 (depends on 8) The device of claim 8, wherein the molten steel formed into droplets by passing through the droplet forming portion is stored in a molten storage portion formed on an opposite side of the molten steel accommodating portion of the tundish body. ### Claim 16 (depends on 15) The device of claim 15, wherein the molten steel formed into droplets by passing through the droplet forming portion is stored in the molten steel storage portion in a state in which the molten steel is refined by passing through slag. ### Claim 17 (depends on 8) The device of claim 8, wherein the droplet forming portion comprises stepped parts, wherein a height of a stepped part adjacent to the molten steel accommodating portion is lower than a height of another stepped part that is more distanced away from the molten steel accommodating portion than the adjacent stepped part. ### Claim 18 (depends on 8) The device of claim 8, wherein the molten steel accommodating portion is configured to receive the molten steel supplied from a ladle via a long nozzle. ### Claim 19 (depends on 8) The device of claim 8, wherein the droplet hole is 6.5 mm or less in diameter.