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CN-117324607-B - Ladle and method for efficiently removing inclusions in molten steel by using same

CN117324607BCN 117324607 BCN117324607 BCN 117324607BCN-117324607-B

Abstract

The invention discloses a ladle and a method for efficiently removing molten steel inclusions by using the same.4 air bricks are uniformly distributed on the circumference of the bottom of the ladle, a steel tapping hole is arranged between any two adjacent air bricks, and the air bricks are distributed at the position of 50-60% of the radius of the ladle. The method comprises the steps of adopting a steel ladle provided with 4 air bricks to receive molten steel, adding alloy and carbon powder into the steel ladle for deoxidization alloying in the tapping process of a converter or an electric furnace, then adding lime and fluorite for slagging, conveying to LF refining for treatment after tapping is finished, adjusting molten steel components and temperature and slag components in the LF refining process, performing calcium treatment on aluminum deoxidization after reaching standards, then performing soft stirring, directly performing soft stirring treatment on the Si-Mn deoxidized steel, and directly conveying the molten steel to continuous casting for pouring after soft stirring is finished. The invention solves the problem of excessive inclusion caused by insufficient floating of the inclusion due to more dead angles of Cheng Gangshui soft blowing of the ladle.

Inventors

  • ZHAO TIANHUA
  • YANG XIAOCHENG
  • DING ZHENTAO
  • TANG CHENGXIN
  • ZHU WENKE

Assignees

  • 常熟市龙腾特种钢有限公司

Dates

Publication Date
20260512
Application Date
20231122

Claims (9)

  1. 1. The method for efficiently removing the inclusions of the molten steel is characterized in that 4 air bricks are uniformly and dispersedly arranged on the circumference of the bottom of the ladle, a steel tapping hole is arranged between two adjacent air bricks, the connecting line between the two adjacent air bricks and the center of the ladle is 90 o degrees, the air bricks are distributed at 50-60% of the position of the radius of the ladle close to the outer side, and the circumferences of the 4 air bricks are sequentially numbered as No. 1 air brick, no. 2 air brick, no. 3 air brick and No. 4 air brick; Controlling high-carbon steel tapping by tapping from a converter or an electric furnace, adopting the steel ladle to receive molten steel, adding alloy and carbon powder into the steel ladle in the tapping process for deoxidization alloying, then adding lime and fluorite for slagging, conveying to LF refining for treatment after tapping is finished, regulating molten steel components, temperature and slag components in the LF refining process, performing calcium treatment on aluminum deoxidized steel after reaching standards, performing soft stirring, directly performing soft stirring treatment on silicon-manganese deoxidized steel, and directly conveying molten steel to continuous casting pouring after soft stirring is finished; The steel tapping of the converter or the electric furnace is carried out by adding alloy and carbon powder, the flow rates of the No. 1 air brick and the No. 4 air brick are 800-1000NL/min, the flow rates of the No.2 air brick and the No. 3 air brick are 400-600NL/min, air blowing stirring is carried out for 30-60 seconds, the flow rates of the No. 1 air brick and the No. 4 air brick are adjusted to be 400-600NL/min, the flow rates of the No.2 air brick and the No. 3 air brick are automatically adjusted by a bottom blowing flow control system according to the rule until the steel tapping is finished, the slag surface of the steel ladle is free from accumulated alloy and carbon powder, slag is melted uniformly, bottom blowing is stopped being adjusted, and the steel ladle is conveyed to an LF refining furnace; And when the LF refining is finished, aluminum sedation is subjected to calcium treatment, the feeding line position is between the No. 1 air brick and the No. 2 air brick, when the feeding line is used, the flow of the No. 1 air brick and the No. 3 air brick is 200-300NL/min, the flow of the No. 2 air brick and the flow of the No. 4 air brick is 100-150NL/min, the air stirring is carried out for 30-60 seconds, the flow of the No. 1 air brick and the flow of the No. 3 air brick is 100-150NL/min, the flow of the No. 2 air brick and the flow of the No. 4 air brick is 200-300NL/min, and according to the rule, the bottom blowing flow control system is automatically adjusted to the end of the calcium treatment, and then the soft stirring treatment is carried out.
  2. 2. The method for efficiently removing molten steel inclusions according to claim 1, wherein the inside of the air brick is an air permeable core, the air permeable core is conical, the outer diameter of the side, which contacts with molten steel, of the air permeable core is 130mm, the outer diameter of the side, which is connected with an air pipe, of the air permeable core is 188mm, air permeable slits on the side, which is connected with the air pipe, are distributed on the inner diameter of the air permeable core for 88mm in one circle, the length of each air permeable slit on the side, which is connected with the air pipe, is 20-30mm in length, the width of each air permeable slit is less than or equal to 1.5mm, the height of each slit in the air permeable core is 410mm, the bottom of each slit in the air permeable core is connected with a porous air base brick, the base brick is 110mm, the air base brick and the air base brick are installed inside the air brick in a sealing manner, and the center of the base brick is connected with an air pipe, and air is blown into the air core.
  3. 3. The method for efficiently removing molten steel inclusions according to claim 1, wherein the diameter of the ladle is 3200mm, and the height x length x width of the air brick is 550mm x 320mm.
  4. 4. The method for efficiently removing molten steel inclusions according to claim 1, wherein the temperature of molten steel tapped from a converter or an electric furnace is more than or equal to 1620 ℃, the C content is 0.05-0.35%, the O content is 0.015-0.035%, a sliding plate is adopted for slag blocking during tapping, and the slag discharge amount is less than or equal to 2.5kg per ton of steel.
  5. 5. The method for efficiently removing molten steel inclusions according to claim 1, wherein when alloy, carbon powder, lime and fluorite are added in the LF refining process to adjust molten steel and slag components, no. 1 air brick, no. 4 air brick flow 300-500NL/min, no. 2 air brick, no. 3 air brick flow 150-250NL/min, air blowing stirring for 30-60 seconds, no. 1 air brick, no. 4 air brick flow 150-250NL/min, no. 2 air brick, no. 3 air brick flow 300-500NL/min are adjusted, and the adjustment is stopped after the adjustment is automatically performed for 4-6 times by a bottom blowing flow control system according to the rule.
  6. 6. The method for efficiently removing molten steel inclusions according to claim 1, wherein when the temperature is raised in the process of LF refining by electrifying, the flow rates of the No. 1 air brick and the No. 2 air brick are 400-600NL/min, the flow rates of the No. 3 air brick and the No. 4 air brick are 200-300NL/min, the air stirring is carried out for 30-60 seconds, the flow rates of the No. 1 air brick and the No. 2 air brick are regulated to be 200-300NL/min, the flow rates of the No. 3 air brick and the No. 4 air brick are regulated to be 400-600NL/min, the temperature is measured after the electrifying is carried out for a certain time by a bottom blowing flow control system, and the regulation is stopped after the temperature reaches the standard.
  7. 7. The method for efficiently removing molten steel inclusions according to claim 1, wherein the calcium treatment is finished, the aluminum killed steel is subjected to soft stirring treatment, LF refining is finished, the silicon manganese killed steel is directly subjected to soft stirring treatment, the flow rate of the No. 1 air brick, the No. 2 air brick and the No. 3 air brick is 50-100NL/min, the flow rate of the No. 4 air brick is 30-50% lower than 50-100NL/min, the slag surface is slightly vibrated by soft blowing Cheng Gangbao, molten steel is not exposed, the soft stirring time is more than or equal to 15 minutes, and then tapping is carried out to continuous casting pouring.
  8. 8. The method for efficiently removing molten steel inclusions according to claim 1, wherein the casting is performed by a 140mm x 140mm billet caster, and the casting is protected throughout the casting.
  9. 9. The method for efficiently removing molten steel inclusions according to claim 1, wherein the continuous casting billet is sampled, the cross section sample is taken, the inclusions are counted by adopting a scanning electron microscope, the counted area is 1000mm 2 , the counted number of oxide inclusions with the size of more than 1 micron is counted, the number of the inclusions with the size of more than or equal to 15 microns is less than 0.005 per mm 2 , the maximum size is not more than 35 microns, and the total number of the inclusions with the size of more than 1 micron is less than or equal to 8.5 per mm 2 .

Description

Ladle and method for efficiently removing inclusions in molten steel by using same Technical Field The invention relates to a ladle and a method for efficiently removing molten steel inclusions by using the ladle, belonging to the technical field of inclusion removal in a steelmaking process. Background The traditional steel ladle generally adopts one air brick or two air bricks, after molten steel smelting is finished, the dead zone of molten steel which is softly blown through Cheng Gangbao is more, the floating of inclusions is insufficient, and the analysis of the inclusions exceeds the standard. The conventional steel ladle with the capacity of 120 tons or more is of a double bottom blowing structure, molten steel refining is finished, and soft blowing treatment is carried out by adjusting the flow of the air brick, so that the main purpose is to remove impurities in the molten steel. Because the whole diameter of the steel ladle with the capacity of 120 tons and more is larger, and the flow of the double air bricks in the soft stirring process is basically consistent, a large amount of dead areas still exist in the molten steel in the blowing soft stirring process, and the floating removal of inclusions is not thorough. Disclosure of Invention In order to solve the problem that the inclusion removal effect is poor in the steelmaking process and the inclusion of a product exceeds the standard, the invention discloses a ladle and a method for efficiently removing the inclusion of molten steel, and the concrete technical scheme is as follows: The steel ladle is characterized in that 4 air bricks are uniformly distributed on the circumference of the bottom of the steel ladle, a steel tapping hole is formed between two adjacent air bricks, the connecting line between the two adjacent air bricks and the center of the steel ladle is 90 o degrees, the air bricks are distributed at 50-60% positions, close to the outer side, of the radius of the steel ladle, and the circumferences of the 4 air bricks are numbered as No. 1 air brick, no. 2 air brick, no. 3 air brick and No. 4 air brick in sequence. Further, the inside of the air brick is an air permeable core, the air permeable core is conical, the outer diameter of the side, in contact with molten steel, of the air permeable core is 130mm, the outer diameter of one side of an air pipe communicated with the air permeable core is 188m, air permeable slits on one side of the air pipe communicated with the air permeable core are distributed at one circle of the inner diameter of the air permeable core, the length of each air permeable slit on one side of the air pipe communicated with the air permeable core is 20-30mm, the width of each air permeable slit is less than or equal to 1.5mm, the height of each slit in the air permeable core is 410mm, the bottoms of the slits in the air permeable core are connected with a porous air permeable base brick, the base brick is 110mm in height and is installed inside the air permeable brick in a sealing mode together with the air permeable brick, the center of the base brick is connected with an air blowing pipe, and air is blown into the air permeable core. Further, the diameter of the ladle is 3200mm, and the height, length and width of the air brick are 550mm, 320mm and 320mm. A method for efficiently removing molten steel inclusion based on the steel ladle comprises the steps of pouring molten steel into the steel ladle after smelting in a converter or an electric furnace, carrying out LF refining, carrying out soft stirring to remove the inclusion after refining, carrying out continuous casting pouring, carrying out steel tapping in the converter or the electric furnace to control high-carbon steel tapping, adopting the steel ladle provided with 4 air bricks to receive molten steel, adding alloy and carbon powder into the steel ladle in the steel tapping process to deoxidize and alloy, then adding lime and fluorite to slag, carrying out LF refining after tapping, regulating the molten steel component, the temperature and the slag component in the LF refining process, carrying out calcium treatment on aluminum deoxidized steel after reaching standards, carrying out soft stirring treatment on silicon-manganese deoxidized steel directly, and carrying out continuous casting pouring after soft stirring. Furthermore, the temperature of molten steel tapped from the converter or the electric furnace is more than or equal to 1620 ℃, the C content is 0.05-0.35%, the O content is 0.015-0.035%, a sliding plate is adopted for slag blocking in the tapping process, and the slag discharge amount per ton of steel is less than or equal to 2.5kg. Further, in the process of adding alloy and carbon powder in the tapping of the converter or the electric furnace, the flow rates of the No. 1 air brick and the No. 4 air brick are 800-1000NL/min, the flow rates of the No. 2 air brick and the No. 3 air brick are 400-600NL/min, the air blowing stirr