CN-122012870-A - RH single-joint clean steel production method

Abstract

The invention belongs to the technical field of steelmaking, and relates to a method for producing RH single-joint clean steel. The method comprises the steps of (1) reforming an RH circulation lifting gas device, (2) producing RH single-process smelted steel types, (3) converter smelting, and (4) controlling RH lifting gas. And in the decarburization period of the RH smelting stage, controlling the standard total flow of oxygen to be in the range of 1500-2500NL/min, switching oxygen into argon after the decarburization period is finished, and introducing argon in the whole process until the RH smelting is finished. The method can effectively prevent the peroxidation of molten steel, reduce the temperature drop in the RH smelting process, reduce the generation of inclusions in the smelting process and improve the cleanliness of the molten steel.

Inventors

• LI NING
• YAN XINHUA
• FENG KONGFANG
• LU CHENG
• LIU XINYUAN
• LIU YUJUN

Assignees

• 张家港中美超薄带科技有限公司
• 江苏省沙钢钢铁研究院有限公司
• 江苏沙钢集团有限公司
• 江苏沙钢钢铁有限公司

Dates

Publication Date

20260512

Application Date

20260210

Claims (6)

1. 1. A method for producing an RH single clean steel, comprising the steps of: (1) Modifying the RH circulation lifting gas device, namely modifying a lifting gas system with original equipment switched by nitrogen and argon into a lifting gas system with three gases of nitrogen, argon and oxygen switched; (2) The steel grade smelted by the RH single-step process is produced, wherein the steel grade smelted by the RH single-step process comprises ultralow-carbon steel grade, the carbon content of a finished product is lower than 0.005 percent, and the carbon content of the finished product is higher than 0.01 percent and lower than 0.03 percent after decarburization and carbon supplement are carried out in the RH process; (3) Converter smelting, namely high-carbon-pulling steel tapping of a converter, wherein the carbon content of the converting end point of the converter is controlled to be 0.35-0.50%, and the oxygen content of the end point of the converter is controlled to be 400-700ppm; (4) RH lifting gas control: non-RH smelting stage, nitrogen aeration, and In the decarburization period of RH smelting stage, the circulation pipeline adopts an aeration mode of taking oxygen as lifting gas, for 180t RH equipment, the standard total flow of oxygen is controlled within the range of 1500-2500NL/min, the standard total flow of oxygen is adjusted according to the conditions of carbon and oxygen content of molten steel entering the station of RH, after the decarburization period is finished, oxygen is switched into argon, argon is introduced in the whole process until RH smelting is completed, After the RH smelting is finished, the lifting gas is changed into nitrogen.
2. 2. The method for improving the surface indentation of a high strength thin strip steel produced by a twin roll casting process of claim 1 wherein: in step (2), the ultra-low carbon steel species include IF steel and electrical steel.
3. 3. The method for improving the surface indentation of a high strength thin strip steel produced by a twin roll casting process of claim 1 wherein: In the step (2), the steel grade subjected to the RH process and decarburization and then carbon supplementing comprises DC01.
4. 4. The method for improving the surface indentation of a high strength thin strip steel produced by a twin roll casting process of claim 1 wherein: In the step (4), argon is used as lifting gas in the RH smelting process when [ O ] - [ C ] in the incoming molten steel is more than or equal to 350 ppm.
5. 5. The method for improving the surface indentation of a high strength thin strip steel produced by a twin roll casting process of claim 1 wherein: In step (4), when 200< -O > - [ C ] <350ppm is in the incoming molten steel, oxygen is adopted as lifting gas in the decarburization period of RH smelting, wherein the total flow rate of oxygen is 1500-2000NL/min in the first stage of the decarburization period, and 2000-2500NL/min in the second stage of the decarburization period, and the standard total flow rate of oxygen is determined according to the difference value between the content of the incoming [ O ] and the content of the incoming [ C ].
6. 6. The method for improving the surface indentation of a high strength thin strip steel produced by a twin roll casting process of claim 1 wherein: in the step (4), when [ O ] - [ C ] < 200ppm in the incoming molten steel, oxygen is adopted as lifting gas in a decarburization period of RH smelting, wherein the total flow rate of the oxygen is 2000NL/min in a first stage of the decarburization period, and 2500NL/min in a second stage of the decarburization period.

Description

RH single-joint clean steel production method Technical Field The invention belongs to the technical field of steelmaking, and relates to a production method of RH single-joint clean steel, which can effectively prevent peroxidation of molten steel, reduce temperature drop in the RH smelting process, reduce the generation of inclusions in the smelting process and improve the cleanliness of the molten steel. Background With the development of RH multifunctional smelting technology, RH steelmaking technology is gradually dominant in the field of high-quality low-cost secondary refining. The low-carbon cold-rolled base plate series steel such as IF steel, electrical steel, ultra-thin ultra-low carbon steel with ultra-thin strip, DC01 and the like is subjected to RH single-joint smelting, and is generally aluminum killed steel except that few special steel types are silicon deoxidized, al 2O3 inclusion is generated in the smelting process, and the steel types have certain requirements on the cleanliness of molten steel. Automobile steel such as IF steel has high requirements on the surface quality of products and strict requirements on indexes of large-size inclusions. Inclusions in electrical steels inhibit grain growth to distort the crystal lattice and prevent domain wall movement, affecting texture composition and deteriorating electrical steel magnetic properties. Improving the cleanliness of the molten steel in the RH single-connection procedure and ensuring the casting forward of the molten steel becomes one of the main subjects of RH smelting. Patent document 201610134591.0 discloses a low-cost and high-efficiency RH production process that improves the RH lifting gas to an oxygen and argon switchable driving gas. This patent is not concerned with improving the cleanliness of the molten steel for cost reasons. In the practical case, the process is not explicitly matched, and the converter process is not explicitly established to create the optimal smelting process conditions for the RH process. This scheme does not clearly show how to switch between oxygen and argon and the detailed method of use. Disclosure of Invention Based on the background technology, the invention aims to provide a production method of RH single-joint clean steel. Through simple equipment transformation and production process optimization, the effects of preventing the peroxidation of molten steel, reducing the temperature drop in the RH process and improving the cleanliness of the molten steel are achieved. The treatment method comprises (1) modifying an RH lifting gas device. The RH circulation lifting gas device is modified, a lifting gas system with original equipment switched by nitrogen and argon is modified into a lifting gas system with three gases switched by nitrogen, argon and oxygen, 2, the carbon content of the end point of molten steel is controlled to be 0.35-0.50% in high-carbon steel drawing of a converter, the oxygen content of the end point is controlled to be 400-700ppm, the peroxidation of the molten steel is prevented, 3, the mixed gas of oxygen and argon is introduced through the lifting gas device in the decarburization period of RH smelting, on one hand, the mixed gas is used as lifting gas, on the other hand, the forced decarburization of the molten steel can be carried out by introducing oxygen, and on the other hand, the temperature drop of the RH process can be effectively reduced by releasing a large amount of heat through secondary combustion of oxygen and carbon monoxide. Thereby greatly improving the cleanliness of the molten steel. More specifically, the invention adopts the following technical scheme. According to one aspect of the invention, a method for producing RH single-joint clean steel is provided, which is characterized by comprising the following steps: (1) Modifying the RH circulation lifting gas device, namely modifying a lifting gas system with original equipment switched by nitrogen and argon into a lifting gas system with three gases of nitrogen, argon and oxygen switched; (2) The steel grade smelted by the RH single-step process is produced, wherein the steel grade smelted by the RH single-step process comprises ultralow-carbon steel grade, the carbon content of a finished product is lower than 0.005 percent, and the carbon content of the finished product is higher than 0.01 percent and lower than 0.03 percent after decarburization and carbon supplement are carried out in the RH process; (3) Converter smelting, namely high-carbon-pulling steel tapping of a converter, wherein the carbon content of the converting end point of the converter is controlled to be 0.35-0.50%, and the oxygen content of the end point of the converter is controlled to be 400-700ppm; (4) RH lifting gas control: non-RH smelting stage, nitrogen aeration, and In the decarburization period of RH smelting stage, the circulation pipeline adopts an aeration mode of taking oxygen as lifting gas, for 180t RH equipment