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CN-121975998-A - Industrial pure iron clean molten steel smelting method based on LF-RH cooperative oxygen control demanganization

CN121975998ACN 121975998 ACN121975998 ACN 121975998ACN-121975998-A

Abstract

The invention discloses an LF-RH synergic oxygen control demanganization-based industrial pure iron clean molten steel smelting method which comprises the following steps of converter smelting, LF refining and RH furnace vacuum treatment, wherein the manganese content of molten steel at the end point is within 0.04%, iron scale is added in the LF refining step for demanganization, the manganese content of the molten steel is treated to be less than or equal to 0.02%, in the RH furnace vacuum treatment step, oxygen blowing demanganization is carried out, every 100-150 m 3 is an oxygen blowing stage, after oxygen blowing of one stage is finished, oxygen blowing is stopped, after circulation is carried out for 1-2 minutes, the manganese content [ Mn ] in the molten steel is rapidly analyzed, the process is repeated until the manganese content [ Mn ] of the molten steel is less than or equal to 0.015%, and aluminum particles are added for deoxidation. The method can controllably reduce the manganese content of the industrial pure iron to below 0.02 percent and the oxygen content to below 5 ppm.

Inventors

  • WANG YUAN
  • MEN CHAOQI
  • LI YUN
  • WANG JINLIN

Assignees

  • 新余钢铁股份有限公司

Dates

Publication Date
20260505
Application Date
20260225

Claims (9)

  1. 1. The method for smelting the industrial pure iron clean molten steel based on LF-RH synergic oxygen control and demanganization is characterized by comprising the following steps of converter smelting, LF refining and RH furnace vacuum treatment; In the converter smelting step, the manganese content of the final molten iron is within 0.04 percent; In the LF refining step, iron scale is added to remove manganese, and the manganese content of molten steel is treated to be less than or equal to 0.02%; In the RH furnace vacuum treatment step, oxygen blowing and demanganization are carried out, each 100-150 m 3 is an oxygen blowing stage, after oxygen blowing of each stage is completed, oxygen blowing is stopped, after circulation is carried out for 1-2 minutes, the manganese content [ Mn ] in molten steel is rapidly analyzed, the process is repeated until the manganese content [ Mn ] in molten steel is less than or equal to 0.015%, and aluminum particles are added for deoxidization.
  2. 2. The method for smelting the industrial pure iron clean molten steel based on LF-RH synergic oxygen control and demanganization according to claim 1, wherein in the converter smelting step, a double slag method is adopted, 3-4 minutes after blowing, high-phosphorus slag is poured out by lifting a gun, the gun position is controlled to be 1.8-1.9m, and 1.5-2.5t ore is dynamically added.
  3. 3. The method for smelting the industrial pure iron clean molten steel based on LF-RH synergic oxygen control and demanganization, which is characterized in that in the converter smelting step, the converter tapping temperature is 1600-1650 ℃.
  4. 4. The method for smelting industrial pure iron clean molten steel based on LF-RH synergic oxygen control and demanganization according to claim 1, wherein in the LF furnace refining step, the adding amount of iron oxide scale is = (inbound [ Mn ]% -LF endpoint [ Mn ]%) × (200000-250000), wherein the adding amount of iron oxide scale is in kg.
  5. 5. The method for smelting industrial pure iron clean molten steel based on LF-RH synergic oxygen control and demanganization according to claim 1, wherein in the RH furnace vacuum treatment step, the flow of oxygen blowing is 1800-2000 m 3 /h.
  6. 6. The method for smelting industrial pure iron clean molten steel based on LF-RH synergic oxygen control and demanganization according to claim 1, wherein aluminum particles are added in two steps in the vacuum treatment step of the RH furnace.
  7. 7. The method for smelting industrial pure iron clean molten steel based on LF-RH cooperative oxygen control demanganization according to claim 6, wherein the amount of aluminum particles added for the first time=molten steel amount× (aluminum component outlet target value+0.005%)/0.85×10+decarburization endpoint oxygen content×33/100+ (1 to 10), wherein the unit of the amount of aluminum particles added for the first time is kg, the unit of molten steel amount is t, the unit of aluminum component outlet target value is%, and the unit of decarburization endpoint oxygen content is ppm.
  8. 8. The method for smelting industrial pure iron clean molten steel based on LF-RH synergic oxygen control and demanganization according to claim 6, wherein in the RH furnace vacuum treatment step, the amount of aluminum particles added for the second time=molten steel amount× (aluminum component outlet target value-actual aluminum content)/0.85x10+ (1-10), wherein the unit of the amount of aluminum particles added for the second time is kg, the unit of the molten steel amount is t, and the units of the aluminum component outlet target value and the actual aluminum content are%.
  9. 9. The method for smelting industrial pure iron clean molten steel based on LF-RH synergic oxygen control and demanganization according to claim 1, wherein in the RH furnace vacuum treatment step, the oxygen content is less than or equal to 5ppm after aluminum particle deoxidation.

Description

Industrial pure iron clean molten steel smelting method based on LF-RH cooperative oxygen control demanganization Technical Field The invention belongs to the technical field of industrial pure iron smelting, and particularly relates to an LF-RH-based industrial pure iron clean molten steel smelting method with coordinated oxygen control and demanganization. Background Industrial pure iron is widely applied to the fields of electronic components, high-grade electrical steel, high-end alloy base materials and the like due to the extremely low impurity content of carbon, silicon, manganese, phosphorus, sulfur and the like and excellent electromagnetic performance and plasticity. The smelting has the core difficulty that impurity elements in molten steel, particularly manganese (Mn) and oxygen (O), are removed to extremely low level, and meanwhile, residual elements such as chromium (Cr), nickel (Ni), copper (Cu) and the like are strictly controlled, so that excessive corrosion to furnace lining and steel ladle refractory materials in the production process is avoided. At present, a process path of converter, LF furnace and RH furnace is generally adopted in the industry to produce industrial pure iron. However, this path has the following general problems: the demanganization efficiency is low, namely the content of manganese at the end point of the converter is higher, the subsequent LF furnace can demanganize, but the actual yield is extremely low, so that the material consumption is huge, the temperature drop is serious, and the demanganizing effect is limited. The RH furnace is overloaded, and because the LF furnace is not thoroughly demanganized, the RH furnace must be subjected to a large amount of oxygen blowing to create a high-oxygen environment for deep demanganization. This not only results in excessive oxidation of the molten steel, but more seriously, the high-oxidability molten steel can severely erode the magnesium-chromium refractory material of the RH vacuum tank, so that chromium (Cr) element in the refractory material is dissolved into the molten steel, causing excessive residual element, and shortening the service life of the equipment. And after the RH furnace is finished, the oxygen content of molten steel is extremely high, the addition is difficult to control accurately by adopting a conventional aluminum deoxidization mode, the content of acid-soluble aluminum (Als) in the molten steel is extremely easy to exceed the standard, the components are out of control, and the product is unqualified. The process route is unclear, and the prior art lacks clear division and cooperation mechanism for the LF furnace and the RH furnace in the demanganization task, so that the whole process has high energy consumption, high cost and poor stability. Disclosure of Invention In order to solve the technical problems, the invention provides the method for smelting the industrial pure iron clean molten steel based on LF-RH cooperative oxygen control demanganization, which can controllably reduce the manganese content of the industrial pure iron to below 0.02 percent and the oxygen content to below 5 ppm. The technical scheme adopted by the invention is as follows: An industrial pure iron clean molten steel smelting method based on LF-RH synergic oxygen control and demanganization comprises the following steps of converter smelting, LF refining and RH furnace vacuum treatment; In the converter smelting step, the manganese content of the final molten iron is within 0.04 percent; In the LF refining step, iron scale is added to remove manganese, and the manganese content of molten steel is treated to be less than or equal to 0.02%; In the RH furnace vacuum treatment step, oxygen blowing and demanganization are carried out, each 100-150 m 3 is an oxygen blowing stage, after oxygen blowing of each stage is completed, oxygen blowing is stopped, after circulation is carried out for 1-2 minutes, the manganese content [ Mn ] in molten steel is rapidly analyzed, the process is repeated until the manganese content [ Mn ] in molten steel is less than or equal to 0.015%, and aluminum particles are added for deoxidization. In the converter smelting step, a double slag method is adopted for operation, 3-4 minutes after blowing is started, a gun is lifted to pour out the blast furnace slag, the gun position in the process is controlled to be 1.8-1.9m, and 1.5-2.5t ore is dynamically added. In the converter smelting step, the converter tapping temperature is 1600-1650 ℃. In the LF furnace refining step, the adding amount of the iron oxide scale is = (entering station [ Mn ]% -LF end point [ Mn ]%) × (200000-250000), wherein the unit of the adding amount of the iron oxide scale is kg. In the RH furnace vacuum treatment step, the flow rate of oxygen blowing is 1800-2000 m 3/h. In the RH furnace vacuum treatment step, aluminum particles are added in two steps. In the RH furnace vacuum treatment step, the amount of aluminum p