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CN-122012871-A - RH aluminum heating method for ultra-low carbon steel

CN122012871ACN 122012871 ACN122012871 ACN 122012871ACN-122012871-A

Abstract

The invention discloses an RH aluminum heating method of ultra-low carbon steel, which comprises the following steps of adding 1-2 kg/(t-steel) of active lime into a ladle when a converter is tapped for more than half, adding 1.5-2.5 kg/(t-steel) of aluminum-containing modifier, adding 0.5-1 kg/(t-steel) of active lime into the ladle after tapping of the converter is completed, and adding RH aluminum heating treatment, RH aluminum deoxidization treatment and steel into molten steel in a vacuum chamber at one time after RH decarburization is finished Adjusting the required metal Then RH aluminum temperature rising treatment, RH aluminum deoxidization treatment and steel treatment are carried out Adjusting and controlling the oxygen blowing amount required by the temperature rise of the oxygen blowing aluminum to be less than or equal to 1.0m 3 /(t.steel), adding limestone into the molten steel in the vacuum chamber, adding active lime on the surface of ladle top slag to perform slag adjustment treatment, and requiring the ladle top slag Is in the range of 1.2 to 1.8. The invention realizes the precise cooperative control of RH refined aluminum temperature rise and refined slag component and fluidity, and meets the requirements of ultra-low carbon steel production on molten steel temperature, components and cleanliness.

Inventors

  • YUAN BAOHUI
  • XIE XIN
  • WANG PAN
  • BAI XUXU
  • JIANG LIUDONG
  • LIU KAI

Assignees

  • 攀钢集团攀枝花钢铁研究院有限公司

Dates

Publication Date
20260512
Application Date
20260324

Claims (10)

  1. 1. The RH aluminum heating method for the ultra-low carbon steel is characterized by comprising the following steps of: When the converter taps more than half of the steel, adding 1-2 kg of active lime/(t-steel) into the ladle, and then adding 1.5-2.5 kg of aluminum-containing modifier/(t-steel); after tapping of the converter is completed, adding 0.5-1 kg/(t.steel) of active lime into the steel ladle, controlling the thickness of slag at the top of the steel ladle to be 60-120 mm, and tapping The content is 300-500 ppm, and tapping is carried out The content is 300-600 ppm, and the steel ladle top slag is The content is less than or equal to 6 percent and the steel ladle top slag ≥2.0; RH decarburization and controlling the oxygen activity of the molten steel to be 200-300 ppm after the completion; adding RH aluminum heating treatment, RH aluminum deoxidization treatment and steel into molten steel in a vacuum chamber at one time Adjusting the required metal Then RH aluminum temperature rising treatment, RH aluminum deoxidization treatment and steel treatment are carried out Adjusting; limestone is added into molten steel in a vacuum chamber, and activated lime is added into the surface of ladle top slag for slag adjustment treatment; And adding alloy into the molten steel in the vacuum chamber, circulating for 6-8 min until RH refining is finished, and discharging the ladle and calming for 15-30 min.
  2. 2. The method for raising RH aluminum temperature of ultra-low carbon steel according to claim 1, wherein RH aluminum temperature raising treatment, RH aluminum deoxidizing treatment and steel are performed Adjusting the total metal required Measuring amount The calculation formula of (2) is as follows: Wherein, the For the metal required by RH aluminum heating treatment The amount of the product is calculated, Metals required for RH aluminum deoxidization The amount of the product is calculated, Is in steel Adjusting the metal required An amount of; metal for RH aluminium heating treatment Measuring amount The calculation formula of (2) is as follows: Wherein, the Is the total mass of the molten steel, The specific heat capacity of the molten steel is 0.84 kJ/(kg DEG C), For the target continuous casting temperature, The temperature of the molten steel at the end of RH decarburization, For the temperature drop from the end of RH decarburization to the continuous casting process, In order to add limestone into molten steel to cause the maximum temperature drop of the molten steel and to add 3 kg/(t.steel) of limestone to cause the maximum temperature drop of the molten steel to 9 ℃, Releasing heat for the reaction of aluminum oxide in steel and taking 28981kJ/kg, Taking 0.7-0.9 for the heat utilization coefficient of RH aluminum heating treatment; metals required for RH aluminum deoxidization treatment Measuring amount The calculation formula of (2) is as follows: Wherein, the For the oxygen content in the steel at the end of RH decarburization, The oxygen content is the target oxygen content and is less than or equal to 0.002% when RH aluminum deoxidization is finished; In steel Adjusting the metal required Measuring amount The calculation formula of (2) is as follows: Wherein, the Is in steel The content control target value is set to a value, For RH refining to continuous casting The loss value is less than or equal to 0.01 percent.
  3. 3. The method for raising the temperature of RH aluminum of ultra-low carbon steel according to claim 2, wherein the oxygen blowing amount required for the temperature raising treatment of RH aluminum is as follows The calculation formula is as follows: Wherein, the The oxygen yield is 0.75-0.95 for RH aluminum temperature rising treatment.
  4. 4. The method for raising the temperature of RH aluminum of ultra-low carbon steel according to claim 3, wherein oxygen is blown by a top lance and the oxygen blowing amount is controlled to be less than or equal to 1m 3 /(t.steel).
  5. 5. The method for raising the temperature of RH aluminum in ultra-low carbon steel according to claim 2, wherein the RH aluminum raising treatment, the RH aluminum deoxidizing treatment and the steel are performed Generation and removal at loss Total amount of inclusions Is calculated according to the formula: Wherein, the Is that Is used for the preparation of a polymer, Is that Is used for the production of a high-molecular-weight silicon-containing polymer, Is in steel The loss is less than or equal to 100ppm, To be generated by The proportion of floating removal of the total amount of the inclusions is 70% -80%.
  6. 6. The method for raising RH aluminum temperature of ultra-low carbon steel according to claim 5, wherein slag conditioning treatment is performed by Is added in the amount of (2) The calculation formula of (2) is as follows: Wherein, the Ladle top slag after modification for RH refining top slag Taking 1.2 to 1.8 as the target value, The density of the steel slag is 3000kg/m 3 , Is the surface area of the top slag of the steel ladle, Is the thickness of the top slag of the steel ladle, In ladle top slag for RH refining Is added to the mass fraction of (c), In ladle top slag for RH refining Mass fraction of (c) is determined.
  7. 7. The method for raising RH aluminum temperature of ultra-low carbon steel according to claim 6, wherein the addition amount of limestone required for slag conditioning The calculation formula of (2) is as follows: Wherein, the In order to adjust the addition amount of active lime required by slag treatment, In limestone Mass fraction of (c) is determined.
  8. 8. The method for raising the temperature of RH aluminum in ultra-low carbon steel according to claim 7, wherein a calculation formula of an effect of raising the temperature of molten steel caused by the RH aluminum raising treatment is as follows: Wherein, the The temperature rising effect of molten steel is caused by RH aluminum temperature rising treatment; RH aluminum deoxidization treatment and steel production Loss causes the temperature rising effect of molten steel Is calculated according to the formula: Wherein, the Is dissolved in steel The heat utilization coefficient of the reaction process with the dissolved oxygen is 0.8-1; the temperature of molten steel is reduced by limestone addition The calculation formula of (2) is as follows: Wherein, the In limestone Is added to the mass fraction of (c), In limestone The decomposition reaction absorbs heat and takes 1780kJ/kg, In limestone The thermal efficiency of decomposition is 0.5-0.8; The calculation formula of the RH refining total molten steel temperature control effect is as follows: Wherein, the The control effect of RH refining total molten steel temperature is achieved.
  9. 9. The method for raising the temperature of RH aluminum in ultra-low carbon steel according to claim 7 or 8, wherein the addition of limestone causes the carbon reduction of the molten steel The calculation formula of (2) is as follows: Wherein, the Is that Is used for the production of a high-molecular-weight silicon-containing polymer, To be generated by And (3) with The reaction limit is less than or equal to 1 percent, Is that Is a relative molecular mass of (a).
  10. 10. The method for raising RH aluminum temperature of ultra-low carbon steel according to claim 1, wherein RH aluminum temperature raising treatment, RH aluminum deoxidizing treatment and steel are performed After adjustment, the molten steel circulates for 3-4 min, limestone is added into the molten steel in the vacuum chamber, and active lime is added into the top slag surface of the steel ladle for slag adjustment treatment.

Description

RH aluminum heating method for ultra-low carbon steel Technical Field The invention belongs to the technical field of ferrous metallurgy, and particularly relates to an RH aluminum heating method for ultra-low carbon steel. Background The RH refining furnace is an important device for producing high-grade ultra-low carbon steel products, and with the rapid development of the markets of automobiles and household appliances, the RH refining furnace has extremely high requirements on the content of C, N and other elements in the ultra-low carbon steel products and the control of the size, the quantity and the type of inclusions in steel, and the RH refining process is a key process for completing the control task. When ultra-low carbon steel is produced by the RH refining process, the RH approach temperature is often lower, so that the temperature of the molten steel needs to be raised by adopting an aluminum-adding oxygen-blowing temperature-raising method in the RH refining furnace. However, a large amount of Al 2O3 inclusions appear in the steel in the RH aluminum heating process, and if the inclusions cannot be removed by rapid floating, the inclusions remain in the steel and the surface inclusion defects of the cold-rolled sheet are caused with a high probability, so that the yield of the steel is affected. For example, patent document with publication number CN117701827A discloses a low-cost RH oxygen blowing temperature rising method, aiming at the heat needing aluminum temperature rising, adding silicon carbide or ferrosilicon and oxygen blowing amount according to the temperature rising amount, adding slag forming materials after aluminum deoxidization, and generating a new slag layer which can isolate silicon oxide from aluminum-containing molten steel, reduce silicon addition and make up for the shortage of silicon components, thereby effectively reducing RH temperature rising cost, but adopting SiC or ferrosilicon temperature rising steel can generate SiO 2 inclusion, so that the SiO 2 content in ladle slag is obviously increased, al in the molten steel is extremely easy to be secondarily oxidized in the subsequent molten steel casting process, thereby increasing [ Al ] S burning loss and increasing inclusion defect rate, and being unfavorable for the improvement of molten steel cleanliness. The patent document with the publication number of CN101392311A discloses an RH-OB molten steel refining method, which adds 0.7-1.4 times of the added Al amount of remelting slag with the grain diameter of 10-20 mm while adding Al for oxygen blowing and heating, wherein the remelting slag contains 45-49% of CaO, 42-48% of Al 2O3, 2-6% of MgO and 1-3% of SiO 2, so that Al 2O3 cluster-shaped inclusions are not generated in steel, the area fraction of the Al 2O3 inclusions is reduced to 0.0020%, the total oxygen is reduced to 0.0015-0.0020%, and the waste amount generated by Al 2O3 inclusions on the surface of a cold rolled sheet is greatly reduced. Therefore, a method for realizing accurate control of temperature and components and ensuring the cleanliness of steel in the RH aluminum heating process is needed at present. Disclosure of Invention The invention provides the RH aluminum heating method for the ultra-low carbon steel, which can facilitate the accurate control of temperature and components and ensure the cleanliness of the steel. The aim of the invention is achieved by the following technical scheme: an RH aluminum heating method of ultra-low carbon steel comprises the following steps: When the converter taps more than half of the steel, adding 1-2 kg of active lime/(t-steel) into the ladle, and then adding 1.5-2.5 kg of aluminum-containing modifier/(t-steel); after tapping of the converter is completed, adding 0.5-1 kg/(t.steel) of active lime into the steel ladle, controlling the thickness of slag at the top of the steel ladle to be 60-120 mm, and tapping The content is 300-500 ppm, and tapping is carried outThe content is 300-600 ppm, and the steel ladle top slag isThe content is less than or equal to 6 percent and the steel ladle top slag≥2.0; RH decarburization and controlling the oxygen activity of the molten steel to be 200-300 ppm after the completion; adding RH aluminum heating treatment, RH aluminum deoxidization treatment and steel into molten steel in a vacuum chamber at one time Adjusting the required metalThen RH aluminum temperature rising treatment, RH aluminum deoxidization treatment and steel treatment are carried outAdjusting; limestone is added into molten steel in a vacuum chamber, and activated lime is added into the surface of ladle top slag for slag adjustment treatment; And adding alloy into the molten steel in the vacuum chamber, circulating for 6-8 min until RH refining is finished, and discharging the ladle and calming for 15-30 min. Further, RH aluminum temperature increasing treatment, RH aluminum deoxidizing treatment and steelAdjusting the total metal requiredMeasuring am