A method for controlling aluminum in molten steel during refining

A technology of refining process and control method, which is applied in the field of molten steel refining, and can solve problems such as difficult narrow range control of Al element in vacuum treatment

Active Publication Date: 2021-08-20
SHOUGANG JINGTANG IRON & STEEL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] Aiming at the deficiencies in the prior art above, the present invention provides a method for controlling aluminum in the refining process of the VD furnace to solve the problem in the prior art that it is difficult to control the Al element in a narrow range in the vacuum treatment of the VD furnace

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  • A method for controlling aluminum in molten steel during refining

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Embodiment 1

[0048] The smelted steel is Q345DH steel, which is produced by the "LF furnace-VD furnace" process route. The ladle capacity is 210t, and the VD outbound aluminum requirement is 0.02-0.060%. The total amount of slag made by LF furnace is 1000kg, the final slag ∑ (FeO+MnO) is 0.81%, and the alkalinity is 6; the aluminum content in the incoming steel of VD furnace is 0.0323%, and the free oxygen content in steel is 4ppm; VD furnace is vacuum refined The total time is 18 minutes, and the deep vacuum is maintained at 23-67Pa for 10 minutes; 3 minutes before the repressurization, the bottom blowing argon gas is adjusted from 130Nl / min to 50Nl / min; 1 minute before the repressurization, 42kg of aluminum block is added; After air-repressurization operation, add 62kg calcium wire and soft blow at the same time.

Embodiment 2

[0050] The smelted steel is E36 steel, aluminum-containing steel, which is produced by the "LF furnace-VD furnace" process route. Ladle capacity is 210t, VD outbound aluminum requirement is 0.02~0.060%. The total amount of slag made by LF furnace is 1100kg, the final slag ∑ (FeO+MnO) is 0.75%, and the alkalinity is 8; the aluminum content in the incoming steel of VD furnace is 0.0305%, and the free oxygen content in steel is 3ppm; VD furnace is vacuum refined The total time is 18 minutes, and the deep vacuum (20~67Pa) is maintained for 11 minutes; 3 minutes before the repressurization, the bottom blowing argon gas is adjusted from 180Nl / min to 30Nl / min, and after adding 40kg aluminum block, it is kept for 1 minute, and the repressurization is performed for 1 minute. Press operation; add 65kg calcium wire for calcium treatment, and soft blow at the same time.

Embodiment 3

[0052] The smelted steel is 45Mn2V steel, which is produced by the "LF furnace-VD furnace" process route. Ladle capacity is 210t, VD outbound aluminum requirement is 0.02-0.060%. The total amount of slag produced by LF furnace is 1150kg, the final slag ∑ (FeO+MnO) is 0.91%, and the alkalinity is 7; The total refining time is 16 minutes, and the deep vacuum (20-67Pa) is kept for 10 minutes; 3 minutes before the repressurization, the bottom blowing argon gas is adjusted from 150Nl / min to 50Nl / min, and after adding 42kg of aluminum block, it is kept for 1 minute, and the vacuum is broken. Repressurization operation; adding 50kg calcium wire for calcium treatment, and soft blowing at the same time, the flow rate of soft blowing is 45Nl / min, take the finished steel sample for analysis, the aluminum content in the steel is 0.0346%, which meets the aluminum content requirements of smelting steel.

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Abstract

The invention discloses a method for controlling aluminum in molten steel during a refining process, which is characterized in that the method includes performing LF refining and VD refining on molten steel; the LF refining includes slagging, and controlling the The content of FeO and MnO, the sum of the mass fraction of FeO and the mass fraction of MnO is 0.5-1.0%; at the end of the LF refining, the mass fraction of aluminum in molten steel is 0.030-0.040%; the VD refining During the process, vacuum treatment was carried out, and an aluminum block was added to the molten steel 1 minute before the end of the vacuum treatment. Adopting the invention, the aluminum loss in the VD refining process is low, only 0.16-0.20%, which saves cost; the hit rate of Alt in the range of 0.025-0.40% at the end of the VD furnace is as high as 91%, and the composition is stably controlled.

Description

technical field [0001] The invention belongs to the technical field of molten steel refining, in particular to a method for controlling aluminum in molten steel during the refining process. Background technique [0002] The smelting of molten steel outside traditional steelmaking furnaces, such as converters and electric furnaces, belongs to secondary refining, often called refining. Commonly used refining methods include LF furnace refining, VD furnace refining, RH refining, etc. LF furnace refining uses white slag for refining. White slag has a strong reducing property in the LF furnace, and it interacts with argon gas stirring to reduce the content of oxygen, sulfur and inclusions in the steel. VD furnace is vacuum degassing equipment, which can be used to produce various alloy structural steel, high-quality carbon steel and low-alloy high-strength steel. In the process of molten steel treatment, it has the metallurgical functions of degassing, deoxidizing, natural deca...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C21C7/00C21C7/072C21C7/076C21C7/10
CPCC21C7/0006C21C7/0056C21C7/072C21C7/076C21C7/10Y02P10/20
Inventor 杨荣光杨赵军闫占辉刘金刚石树东高宠光王国连杨振旺王宏宇周磊王东柱谢翠红李阳
Owner SHOUGANG JINGTANG IRON & STEEL CO LTD
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