CN-117626100-B - High-purity stainless steel billet prepared by short process and preparation method thereof

Abstract

The invention provides a high-purity stainless steel billet prepared by a short process and a preparation method thereof, belonging to the technical field of stainless steel smelting. According to the invention, through medium-frequency induction furnace scrap steel smelting, AOD furnace molten steel deoxidization mixed flushing, LF furnace refining and continuous casting, molten steel with w (T.O) below 45ppm and casting blank with w (T.O) below 50ppm are obtained. The invention adopts the strict slag-making process of the intermediate frequency induction furnace, the whole argon-blowing and deoxidizing slag-washing process of the intermediate frequency induction furnace tapping, the whole argon-blowing and deoxidizing process of the AOD furnace tapping, the whole argon-blowing and stirring process of the mixed flushing molten steel entering a station, the optimization of the refining slag system of the mixed flushing molten steel LF furnace, the improvement of the refining molten steel calcium treatment and the soft blowing process, the optimization of various aspects such as continuous casting slag-making control process, the protection casting process, the crystallizer flow field and the like, reduces the content of inclusion and residual elements in the LF refining molten steel and steel billet, improves the quality of casting blanks, and has important significance for popularization and application of the low-cost high-quality short-flow stainless steel smelting process.

Inventors

• MENG ZHENGBING
• He Zixun
• CHEN YUZHI
• HUANG LEI
• JI JIANMIN
• WANG PAN
• ZHOU CHUNQUAN
• LIU GUANGMU

Assignees

• 桂林理工大学

Dates

Publication Date

20260512

Application Date

20231227

Claims (3)

1. 1. The preparation method for preparing the high-purity stainless steel billet in a short process is characterized by comprising the following steps of: (1) Smelting in an intermediate frequency induction furnace, namely hanging stainless steel scraps into the intermediate frequency induction furnace in batches for smelting, and performing slag tapping to obtain molten steel smelted in the intermediate frequency induction furnace, hanging a ladle into a ladle car, and tapping to the ladle; (2) The method comprises the steps of carrying out deoxidization and mixing flushing on molten steel in an AOD furnace, namely, driving a ladle car filled with molten steel in an intermediate frequency induction furnace under the AOD furnace, tapping molten steel in the AOD furnace into a ladle filled with molten steel in the intermediate frequency induction furnace for mixing flushing; (3) Ladle Furnace (LF) molten steel refining, namely transferring the molten steel mixed and washed in the step (2) into a refining station, adding ferrosilicon powder, lime and fluorite deoxidization slag-forming materials, feeding a calcium silicate wire after refining, and carrying out soft blowing to obtain qualified molten steel, and continuously casting the molten steel to obtain a high-purity stainless steel billet; The temperature of molten steel smelted by the AOD furnace is 1580-1620 ℃, before the molten steel of the AOD furnace is tapped to a steel ladle each time and is filled with intermediate frequency molten steel, reducing slag of the AOD furnace with the thickness of 300-500 mm is required to be added to the steel ladle, and slag is formed in advance for an LF furnace; The steel ladle car filled with the molten steel of the intermediate frequency induction furnace is started under an AOD furnace, argon is introduced 5-10 minutes before tapping of the molten steel of the AOD furnace, the mass ratio of the molten steel of the AOD furnace to the molten steel smelted by the intermediate frequency induction furnace is 1:0.9-1.2, 0.5-1.0 kg of ferrosilicon and 1.0-1.5 kg of barium silicon are added per ton of steel along the steel flow during tapping, and argon is blown and stirred in the whole process during tapping and mixing flushing; After the mixed molten steel enters the LF refining station, ferrosilicon powder, lime and fluorite deoxidizing and slagging materials are added according to the color of slag and the fluidity of slag, when the slag turns white and the fluidity is good, temperature measurement and sampling analysis are carried out, the temperature and the components of the refined molten steel are adjusted according to the analysis result, and when the temperature and the components meet the requirements, the molten steel is fed into a calcium silicate wire for inclusion denaturation treatment; And (3) feeding a calcium wire with the length of 100-200 m at a speed of 3-4 m/s after the temperature of the refined molten steel exceeds 50-70 ℃ of the liquidus temperature, and carrying out soft argon blowing for 10-15 minutes after the calcium wire is fed, and controlling w (T.O) in the LF out-station molten steel to be below 45 ppm.
2. 2. The preparation method of claim 1, wherein the temperature of molten steel after melting in the step (1) is 1610-1630 ℃, a strict slag-beating process is performed, slag of an intermediate frequency induction furnace is removed until the molten steel is exposed, 3-5 kg of metallurgical lime is added per ton of steel at the bottom of a ladle before a ladle car is driven into the intermediate frequency induction furnace, an argon pipe is connected, 0.5-1.0 kg of ferrosilicon and 1.0-1.5 kg of barium calcium silicate are added per ton of steel along the flow of steel during tapping, and argon blowing and stirring are performed in the whole process so as to realize molten steel deoxidization and slag washing processes.
3. 3. The preparation method of the casting blank according to claim 1, wherein the argon blowing protection pouring of the long nozzle, the stopper rod and the sliding plate part in the steel ladle is carried out in the continuous casting in the step (3), the argon blowing protection flow is respectively 10-15L/min, 3-5L/min and 2-3L/min, the insertion depth of the SEN submerged nozzle is adjusted to be 150-180 mm, the dip angle of the nozzle outlet is 5-8 degrees, the temperature difference of water inlet and outlet of a crystallizer is 7-9 ℃, and w (T.O) in the casting blank is controlled below 50 ppm.

Description

High-purity stainless steel billet prepared by short process and preparation method thereof Technical Field The invention relates to the technical field of stainless steel smelting, in particular to a high-purity stainless steel billet prepared by a short process and a preparation method thereof. Background The stainless steel has wide application range, plays an important role in the fields of aviation, ships, petrochemical industry and the like, and is widely applied to the aspects of transportation, kitchen ware, household appliances, building equipment and the like. With the high-speed development of the economy of China in the past decades, the steel yield of China, especially the stainless steel production and consumption, are also rapidly improved. The current low-cost long-flow stainless steel smelting can obtain qualified molten steel by mineral separation, sintering, blast furnace smelting, AOD furnace smelting and LF furnace refining, and the flow is long, and the cost is obviously higher than that of the short-flow molten steel of an intermediate frequency induction furnace and an LF furnace. However, the traditional intermediate frequency induction furnace and LF furnace short-flow stainless steel molten steel has high content of Zn, sn and other harmful residual elements and inclusions, and the quality of continuous casting billets cannot be ensured. Therefore, developing a new process with short flow to improve the product quality and reduce the production cost has become a key factor for the survival and development of stainless steel enterprises. Disclosure of Invention The invention aims to provide a high-purity stainless steel billet prepared by a short process and a preparation method thereof, which reduce the production cost of stainless steel smelting. In order to achieve the above object, the present invention provides the following technical solutions: The invention provides a preparation method for preparing a high-purity stainless steel billet in a short process, which comprises the following steps: (1) Smelting in an intermediate frequency induction furnace, namely hanging stainless steel scraps into the intermediate frequency induction furnace in batches for smelting, and performing slag tapping to obtain molten steel smelted in the intermediate frequency induction furnace, hanging a ladle into a ladle car, and tapping to the ladle; (2) The method comprises the steps of carrying out deoxidization and mixing flushing on molten steel in an AOD furnace, namely, driving a ladle car filled with molten steel in an intermediate frequency induction furnace under the AOD furnace, tapping molten steel in the AOD furnace into a ladle filled with molten steel in the intermediate frequency induction furnace for mixing flushing; (3) And (3) refining the molten steel in the LF furnace, namely transferring the molten steel mixed and washed in the step (2) into a refining station, adding deoxidizing and slagging materials such as ferrosilicon powder, lime, fluorite and the like, feeding a calcium silicate wire after refining, and carrying out soft blowing to obtain qualified molten steel, and continuously casting the molten steel to obtain the high-purity stainless steel billet. Further, the temperature of molten steel after melting in the step (1) is 1610-1630 ℃, a slag-beating process is carried out, slag of the intermediate frequency induction furnace is removed until the molten steel is exposed, 3-5 kg of metallurgical lime is added per ton of steel at the bottom of a ladle before a buggy ladle is driven into the intermediate frequency induction furnace, an argon pipe is connected, 0.5-1.0 kg of ferrosilicon and 1.0-1.5 kg of calcium-silicon barium are added per ton of steel along the steel flow during tapping, and argon blowing stirring is carried out in the whole process so as to realize molten steel deoxidization and slag washing processes. Further, the temperature of molten steel smelted by the AOD furnace in the step (2) is 1580-1620 ℃, and before the molten steel of the AOD furnace is tapped to a steel ladle each time and mixed with the molten steel filled with intermediate frequency, reducing slag of the AOD furnace with the thickness of 300-500 mm is required to be added to the steel ladle, and slagging is carried out on the LF furnace in advance. Further, in the step (2), the buggy ladle filled with the molten steel of the intermediate frequency induction furnace is driven into an AOD furnace, argon is introduced 5-10 minutes before tapping of the molten steel of the AOD furnace, the mass ratio of the molten steel of the AOD furnace to the molten steel smelted by the intermediate frequency induction furnace is 1:0.9-1.2, 0.5-1.0 kg of ferrosilicon and 1.0-1.5 kg of barium silicon are added per ton of steel along the steel flow during tapping, and argon is blown and stirred in the whole process during tapping and mixing flushing. And (3) continuously blowing argon before the mixed mol