CN114381648A - Method for eliminating warping on surface of thermal system alloy steel - Google Patents
Method for eliminating warping on surface of thermal system alloy steel Download PDFInfo
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C33/00—Making ferrous alloys
- C22C33/04—Making ferrous alloys by melting
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C1/00—Refining of pig-iron; Cast iron
- C21C1/02—Dephosphorising or desulfurising
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
- C21C5/28—Manufacture of steel in the converter
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
- C21C5/28—Manufacture of steel in the converter
- C21C5/30—Regulating or controlling the blowing
- C21C5/34—Blowing through the bath
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/04—Removing impurities by adding a treating agent
- C21C7/072—Treatment with gases
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/04—Removing impurities by adding a treating agent
- C21C7/076—Use of slags or fluxes as treating agents
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/0221—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
- C21D8/0226—Hot rolling
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D2211/00—Microstructure comprising significant phases
- C21D2211/005—Ferrite
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
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Abstract
The invention relates to the technical field of steelmaking processes, in particular to a method for eliminating warping on the surface of thermal alloy steel. The method comprises the following steps: smelting molten iron in a converter to obtain molten steel after the converter; refining and smelting the molten steel after the furnace to obtain refined molten steel; carrying out continuous casting and stack cooling on the refined molten steel in sequence to obtain a plate blank; the nitrogen content of the molten steel after the furnace is less than or equal to 28ppm by mass concentration; the nitrogen increasing amount of the refined molten steel is less than or equal to 6ppm by mass concentration; in the continuous casting process, the nitrogen increasing amount is less than or equal to 3ppm by mass concentration, and the nitrogen content of the plate blank is less than or equal to 40ppm by mass concentration; in the slab, the metallographic structure comprises 100% of ferrite in volume fraction; the nitrogen content and the cold storage low-temperature hot delivery process reduce the precipitation of second phase particles, ensure that austenite is completely converted into ferrite, and eliminate the defect of hot rolling and warping.
Description
Technical Field
The invention relates to the technical field of steelmaking processes, in particular to a method for eliminating warping on the surface of thermal alloy steel.
Background
The surface of the hot system alloy steel containing wheels, rims, girders and the like is prone to surface skin warping in the hot rolling process, and the defects are distributed on the surface in a runway shape, so that the product quality is greatly influenced, batch quality accidents are easily formed, and meanwhile, large batch slab backing is caused, and the steel-rolling interface is influenced.
The research shows that the micro-alloy steel is easy to generate surface cracks under the condition of hot delivery and hot charging process, no defect is found on the surface after the surface is inspected before the casting blank is cold-charged or hot-charged, and the cracks can be observed to be distributed along the direction of vibration marks or in a net shape on the surface in hot rolling, including rough rolling of an intermediate blank, wherein the depth of the cracks is 0.3-2.2 mm, the maximum width is about 1.5mm, or the surface is warped.
Disclosure of Invention
The application provides a method for eliminating surface warping of thermal system alloy steel, and aims to solve the technical problem that the surface warping occurs in hot rolling of the thermal system alloy steel.
In a first aspect, the present application provides a method for eliminating surface warping of a thermal system alloy steel, comprising the following steps:
smelting molten iron in a converter to obtain molten steel after the converter;
refining and smelting the molten steel after the furnace to obtain refined molten steel;
carrying out continuous casting and stack cooling on the refined molten steel in sequence to obtain a plate blank;
the nitrogen content of the molten steel after the furnace is less than or equal to 28ppm by mass concentration; the nitrogen increasing amount of the refined molten steel is less than or equal to 6ppm by mass concentration; in the continuous casting process, the nitrogen increasing amount is less than or equal to 3ppm by mass concentration, and the nitrogen content of the plate blank is less than or equal to 40ppm by mass concentration;
the metallurgical structure of the slab comprises 100% of ferrite in volume fraction.
Optionally, the smelting of the molten iron in the converter comprises the following steps of: and carrying out pre-desulfurization and slagging-off treatment to obtain molten iron, wherein Si in the molten iron is more than 0.10 percent by mass, the temperature of the molten iron is more than 1300 ℃, and the slagging-off rate of the slagging-off treatment is more than or equal to 95 percent.
Optionally, the converter smelting comprises converter bottom blowing and semisteel smelting; the converter bottom blowing comprises: carrying out bottom blowing of the converter by using inert gas; the semi-steel smelting comprises the following steps: carrying out slag remaining operation in a semisteel smelting mode; the flow of the bottom blowing of the converter is less than or equal to 1000Nm3/h。
Optionally, the refining and smelting comprises: refining and smelting by micro positive pressure in the whole process; the refining smelting further comprises the following steps: and after the ladle arrives at the station, lowering the ladle cover, and after the ladle cover is lowered to the lower limit position, opening the gas to pre-blow argon and keeping the position of the ladle cover, wherein the pre-blowing argon time is 3-4 min.
Optionally, the circular seam between the ladle and the smoke hood is less than or equal to 100mm, and the ladle and the smoke hood are sealed.
Optionally, the refining smelting adopts submerged arc operation, and the argon flow and/or slag charge addition is controlled in the temperature rise process of the refining smelting to ensure the submerged arc effect; the slag comprises synthetic slag and/or aluminum slag.
Optionally, the synthetic slag comprises the following components in percentage by mass: 60-70%, CaF 2: 8-20% of Al2O3: 5-15%, MgO: 5-10%, the balance being unavoidable impurities; the components of the aluminum slag comprise more than or equal to 20 percent of Al and Al2O3: 20-70 percent of CaO, less than or equal to 15 percent of CaO, and the balance of inevitable impurities.
Optionally, the argon flow is 300-800Nm3/h。
Optionally, the continuous casting includes a drawing speed control and a casting protection, the drawing speed control includes a drawing speed control of not less than 1.0m/min, and the casting protection includes: and (4) carrying out protective casting on the ladle sleeve, wherein the flow of argon is less than or equal to 25L/min.
Optionally, the heap cooling time is 4-10 h, and the slab temperature is 550-600 ℃.
Compared with the prior art, the technical scheme provided by the embodiment of the application has the following advantages:
according to the method provided by the embodiment of the application, the nitrogen content of the molten steel after the furnace is controlled to be less than or equal to 28ppm by mass concentration, so that the nitrogen content of the molten steel after the furnace can be ensured; controlling the nitrogen increasing amount of the refined molten steel to be less than or equal to 6ppm by a mass concentration meter, so that the nitrogen content of the refined molten steel can be ensured; controlling the nitrogen increasing amount to be less than or equal to 3ppm by a mass concentration meter in the continuous casting process, controlling the nitrogen content of the plate blank to be less than or equal to 40ppm by the mass concentration meter, and controlling the nitrogen content and the nitrogen increasing amount in each process to ensure that the nitrogen content of the finished steel is controlled within 40ppm and ensure the quality of the finished steel; the method effectively ensures the comprehensive action of total nitrogen and other components in the continuous casting process and all previous processes, forms a casting blank with good quality, and reduces the phenomenon of surface warping of the slab of the thermal alloy steel during the hot rolling process; and a low-temperature hot conveying process for controlling nitrogen content and stack cooling is adopted, so that the precipitation of second-phase particles is reduced, the completion of austenite phase transformation is ensured, and the defect of hot-rolled coil warping is eliminated.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and together with the description, serve to explain the principles of the invention.
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following embodiments or the drawings used in the description of the prior art are briefly described, and it is obvious for those skilled in the art to obtain other drawings without any inventive exercise.
FIG. 1 is a schematic flow chart illustrating a method for eliminating surface warping of thermal alloy steel according to an embodiment of the present disclosure;
FIG. 2 is a surface effect diagram of a steel coil provided in example 1 and comparative example 1 of the present application;
fig. 3 is a metallographic structure diagram of a steel coil provided in example 1 and comparative example 1 of the present application.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some embodiments of the present application, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
Fig. 1 is a schematic flow chart of an xx method according to an embodiment of the present application.
The application provides a method for eliminating surface warping of thermal series alloy steel, as shown in figure 1, the method comprises the following steps:
s1, smelting molten iron in a converter to obtain molten steel after the converter;
s2, refining and smelting the molten steel after the furnace to obtain refined molten steel;
s3, carrying out continuous casting and heap cooling on the refined molten steel in sequence to obtain a plate blank;
the nitrogen content of the molten steel after the furnace is less than or equal to 28ppm by mass concentration; the nitrogen increasing amount of the refined molten steel is less than or equal to 6ppm by mass concentration; in the continuous casting process, the nitrogen increasing amount is 3ppm by mass concentration, and the nitrogen content of the plate blank is less than or equal to 40ppm by mass concentration; the metallurgical structure of the slab comprises 100% of ferrite in volume fraction.
In the embodiment of the application, the low-temperature hot conveying process for controlling the nitrogen content and the heap cooling is adopted, the precipitation of second-phase particles is reduced, the austenite is ensured to complete phase transformation, and the defect of hot rolling and warping is eliminated.
As an optional embodiment, before the molten iron is smelted in a converter to obtain molten steel after the converter, the method includes: and carrying out pre-desulfurization and slagging-off treatment to obtain molten iron, wherein Si in the molten iron is more than 0.10 percent by mass, the temperature of the molten iron is more than 1300 ℃, and the slagging-off rate of the slagging-off treatment is more than or equal to 95 percent.
In the embodiment of the application, the molten iron pre-desulfurization can be carried out by a KR stirring method or a blowing method.
KR stirring method stirs the molten iron through the agitator rotation in the molten iron jar, makes the molten iron produce the swirl, is drawn into the molten iron inside with the desulfurizer that adds and fully reacts to realize the molten iron desulfurization, have desulfurization efficiency height, the desulfurizer consumes few, characteristics such as metal loss low.
The blowing method is to blow the desulfurizing agent into a torpedo car or a ladle of a steel plant, which transports molten iron, by using carrier gas through a spray gun, so that the powder fully contacts with the molten iron and sulfur is removed in the upward floating process.
As an alternative embodiment, the converter smelting comprises converter bottom blowing and semisteel smelting; the converter bottom blowing comprises: carrying out bottom blowing of the converter by using inert gas; the semi-steel smelting comprises the following steps: carrying out slag remaining operation in a semisteel smelting mode; the flow rate of the bottom blowing of the converter is 1000Nm3/h。
Conventionally, the flow rate of bottom blowing of the converter is generally less than or equal to 1500Nm3The flow rate of bottom blowing of the converter is less than or equal to 1000Nm3The excellent effects of uniform stirring and low nitrogen content molten steel can be achieved.
In the embodiment of the present application, any converter bottom blowing that can achieve the effect may be used, the inert gas includes helium (He), neon (Ne), argon (Ar), krypton (Kr), and xenon (Xe), and argon is the cheapest, and argon is selected to save cost.
As an alternative embodiment, the refinery process comprises: refining and smelting by micro positive pressure in the whole process; the refining smelting further comprises the following steps: and after the ladle arrives at the station, lowering the ladle cover, and after the ladle cover is lowered to the lower limit position, opening the gas to pre-blow argon and keeping the position of the ladle cover, wherein the pre-blowing argon time is 3-4 min.
In the embodiment of the application, the converter bottom blowing mode can adopt a full argon blowing mode. After the ladle arrives at the station, the ladle cover is lowered to the lower limit position, then the gas can be opened for pre-argon blowing operation, the argon blowing time is controlled to be 3-4min, and the molten steel exposure time is reduced; during smelting, the argon flow is adjusted to 300-800Nm3And h, ensuring that the slag surface is not exposed. The micro-positive pressure reducing atmosphere in the furnace is ensured, and the contact between the molten steel and the air is reduced.
In an alternative embodiment, an annular gap between the ladle and the smoke hood is 100mm, and the ladle and the smoke hood are sealed.
In the embodiment of the application, the circular seam between the steel ladle and the smoke cover is not more than 100mm, and the steel ladle and the smoke cover are sealed, so that good submerged arc and air isolation effects are achieved, and the quality of molten steel is guaranteed.
As an optional embodiment, the refining smelting adopts a submerged arc operation, and the argon flow and/or slag charge addition is controlled in the temperature rise process of the refining smelting to ensure the submerged arc effect; the slag comprises synthetic slag and/or aluminum slag.
In the embodiment of the application, the submerged arc operation is adopted, and because the nitrogen is easily increased when the molten steel is exposed in the temperature rise process, the argon is well controlled in the temperature rise process to ensure the submerged arc effect, when the submerged arc effect is not good, 150-350kg of synthetic slag can be added, and 20-60kg of aluminum slag can improve the submerged arc effect.
As an optional embodiment, the synthetic slag comprises the following components in percentage by mass: 60-70%, CaF2：8-20％，Al2O3: 5-15%, MgO: 5-10%, the balance being unavoidable impurities; the components of the aluminum slag comprise more than or equal to 20 percent of Al and Al2O3：20-70 percent of CaO, less than or equal to 15 percent of CaO, and the balance of inevitable impurities.
In the embodiment of the application, the addition amount of the synthetic slag is 150-350kg, and the addition amount of the aluminum slag is 20-60 kg. The synthetic slag has the excellent effect of rapid slag melting, and the submerged arc effect can be effectively ensured; the aluminum slag can effectively improve the submerged arc effect and the desulfurization rate by reducing the oxidability in the slag.
As an alternative embodiment, the argon flow may be 300-800Nm3/h。
In the embodiment of the application, the argon flow is adjusted to 300-800Nm during the smelting3And h, ensuring that the slag surface is not exposed, and ensuring the submerged arc effect by making argon.
As an optional embodiment, the continuous casting comprises drawing speed control and casting protection, the drawing speed control comprises the control of the drawing speed to be more than or equal to 1.0m/min, and the casting protection comprises the following steps: and carrying out protective casting on the steel ladle sleeve, wherein the flow of argon is less than or equal to 25L/min.
In the embodiment of the application, the pulling speed is controlled, casting is protected, the nitrogen content in the plate blank is ensured to be within a preset range in order to control the nitrogen increasing amount of molten steel, and the technical problems of warping and the like in the subsequent process are avoided.
As an optional implementation mode, the heap cooling time can be 4-10 h, and the slab temperature can be 550-600 ℃.
In the embodiment of the application, the slab adopts a heap cooling process. By adopting the nitrogen content control and low-temperature hot conveying process, the precipitation of second phase particles is reduced, the completion of austenite phase transformation is ensured, the occurrence of the defect of hot rolled coil warping is reduced, the feeding temperature is controlled within 600 ℃, and the excellent effect of reducing the surface cracks of the steel coil can be achieved.
Example 1
A method for controlling the surface warping defect of alloy hot-line variety steel comprises the steps of feeding molten iron with Si content of 0.25%, molten iron temperature of 1350 ℃ and KR slagging-off rate of 96%; the bottom blowing mode of the converter adopts a full argon blowing mode, and the conventional smelting bottom blowing flow is 1200Nm3The nitrogen content after the converter is 25 ppm; after the ladle arrives at the refining station, argon blowing time is 3min, and smelting is carried outArgon flow during refining is 600Nm3H, increasing nitrogen by 4ppm in the refining process; the continuous casting cross section is 1300mm, the drawing speed is 1.4m/min, the argon flow of the steel sheath pipe is 25L/min, the continuous casting nitrogen increase is 3ppm, and the nitrogen content of the finished steel is 32 ppm; the slab adopts a heap cooling process, the heap cooling time is 5 hours, the temperature of the cast blank after the heap cooling is about 560 ℃, and the feeding temperature is 500 ℃; no defect exists after hot rolling. As shown in fig. 2 and 3. Wherein, the left figure of fig. 2 is the surface effect diagram of the steel coil in the embodiment 1, and the left figure of fig. 3 is the metallographic structure diagram of the steel coil in the embodiment 1.
Example 2
A method for controlling the surface warping defect of alloy hot-line variety steel comprises the steps of feeding molten iron into a furnace, wherein the Si content is 0.30%, the temperature of the molten iron is 1360 ℃, and the KR slag-removing rate is ensured to be 97%; the bottom blowing mode of the converter adopts a full argon blowing mode, and the later flow of the bottom blowing of the semi-steel smelting converter is 850Nm3Adopting slag retention operation, wherein the nitrogen content after the converter is 26 ppm; after the ladle arrives at the refining station, argon blowing time is 3.5min, and argon flow during smelting is 500Nm3H, increasing nitrogen by 5ppm in the refining process; 1400mm of continuous casting section, 1.3m/min of drawing speed, 25L/min of argon flow of the steel sheath pipe, 2ppm of continuous casting nitrogen increase and 33ppm of nitrogen content of finished steel; the slab adopts a heap cooling process, the heap cooling time is 6 hours, the temperature of a casting blank after the heap cooling is about 550 ℃, and the feeding temperature is 510 ℃; no defect exists after hot rolling.
Comparative example 1
In this comparative example, the slab was directly hot rolled at a feed temperature of about 700 ℃ without using a heap cooling process, otherwise the same as in example 1. As shown in fig. 2 and 3. Wherein the right figure of fig. 2 is a surface effect diagram of the steel coil of the comparative example 1, and the right figure of fig. 3 is a metallographic structure diagram of the steel coil of the comparative example 1.
Comparative example 2
In this comparative example, the slab was subjected to the heap cooling process, the heap cooling time was 3 hours, the slab temperature was 650 ℃ and hot rolling was performed, otherwise the same as in example 1.
Comparative example 3
In the comparative example, the nitrogen content of the molten steel after the furnace is 35ppm by mass concentration; the nitrogen increasing amount of the refined molten steel is 10ppm by mass concentration; in the continuous casting process, the nitrogen increasing amount is 8ppm by mass concentration, and the nitrogen content of the slab is 53ppm by mass concentration.
Comparative example 4
In the comparative example, the nitrogen content of the molten steel after the furnace is 32ppm by mass concentration; the nitrogen increasing amount of the refined molten steel is 8ppm by mass concentration; in the continuous casting process, the nitrogen increasing amount is 6ppm by mass concentration, and the nitrogen content of the plate blank is 46ppm by mass concentration.
Table 1.
In table 1, the difference between the nitrogen content and the heap cooling process in the examples and the comparative examples determines the difference of the surface warping degree of the finished steel after metallographic hot rolling, wherein the warping incidence of the example group is 0, the warping defect incidence of the comparative example group is different from 33% to 56%, the metallographic structure in the examples is ferrite, the metallographic structure in the comparative examples is austenite and ferrite, and the surface warping phenomenon is more likely to occur in the comparative example group after hot rolling.
It is noted that, in this document, relational terms such as "first" and "second," and the like, may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.
The foregoing are merely exemplary embodiments of the present invention, which enable those skilled in the art to understand or practice the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (10)
1. A method for eliminating the warping of the surface of thermal alloy steel is characterized by comprising the following steps:
smelting molten iron in a converter to obtain molten steel after the converter;
refining and smelting the molten steel after the furnace to obtain refined molten steel;
carrying out continuous casting and stack cooling on the refined molten steel in sequence to obtain a plate blank;
the nitrogen content of the molten steel after the furnace is less than or equal to 28ppm by mass concentration; the nitrogen increasing amount of the refined molten steel is less than or equal to 6ppm by mass concentration; in the continuous casting process, the nitrogen increasing amount is less than or equal to 3ppm by mass concentration, and the nitrogen content of the plate blank is less than or equal to 40ppm by mass concentration;
the metallurgical structure of the slab comprises 100% of ferrite in volume fraction.
2. The method of claim 1, wherein the converter smelting of the molten iron to obtain the post-furnace molten steel comprises: and carrying out pre-desulfurization and slagging-off treatment to obtain molten iron, wherein Si in the molten iron is more than 0.10 percent by mass, the temperature of the molten iron is more than 1300 ℃, and the slagging-off rate of the slagging-off treatment is more than or equal to 95 percent.
3. The method of claim 1, wherein the converter smelting comprises converter bottom blowing and semisteel smelting; the converter bottom blowing comprises: carrying out bottom blowing of the converter by using inert gas; the semi-steel smelting comprises the following steps: carrying out slag remaining operation in a semisteel smelting mode; the flow of the bottom blowing of the converter is less than or equal to 1000Nm3/h。
4. The method of claim 1, wherein the refinery smelting comprises: refining and smelting by micro positive pressure in the whole process; the refining smelting further comprises the following steps: and after the ladle arrives at the station, lowering the ladle cover, and after the ladle cover is lowered to the lower limit position, opening the gas to pre-blow argon and keeping the position of the ladle cover, wherein the pre-blowing argon time is 3-4 min.
5. The method according to claim 4, wherein the annular seam between the ladle and the hood is less than or equal to 100mm, and the ladle and the hood are sealed.
6. The method according to claim 1, wherein the refining smelting adopts a submerged arc operation, and the temperature rise process of the refining smelting controls the flow of argon and/or adds slag charge to ensure the submerged arc effect; the slag comprises synthetic slag and/or aluminum slag.
7. The method according to claim 6, wherein the synthetic slag comprises the following components in percentage by mass: 60-70%, CaF2：8-20％，Al2O3: 5-15%, MgO: 5-10%, the balance being unavoidable impurities; the components of the aluminum slag comprise more than or equal to 20 percent of Al and Al2O3: 20-70 percent of CaO, less than or equal to 15 percent of CaO, and the balance of inevitable impurities.
8. The method as claimed in claim 6, wherein the argon flow is 300-800Nm3/h。
9. The method according to claim 1, wherein the continuous casting comprises a drawing speed control and a casting protection, the drawing speed control comprises a drawing speed control of more than or equal to 1.0m/min, and the casting protection comprises: and carrying out protective casting on the steel ladle sleeve, wherein the flow of argon is less than or equal to 25L/min.
10. The method according to claim 1, wherein the heap cooling time is 4-10 hours, and the slab temperature is 550-600 ℃.
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2002030324A (en) * | 2000-07-14 | 2002-01-31 | Sumitomo Metal Ind Ltd | Method for producing ridging-resistant ferritic stainless steel |
| CN103173586A (en) * | 2013-04-15 | 2013-06-26 | 攀钢集团攀枝花钢铁研究院有限公司 | Method for lowering contents of oxygen and nitrogen in molten steel at smelting end in semisteel smelting converter |
| CN103627841A (en) * | 2013-11-01 | 2014-03-12 | 南京钢铁股份有限公司 | Control method for nitrogen content of molten steel of wear-resistant steel |
| CN108273971A (en) * | 2018-03-05 | 2018-07-13 | 首钢京唐钢铁联合有限责任公司 | A method of reducing casting process molten steel nitrogen increased amount |
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2021
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Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2002030324A (en) * | 2000-07-14 | 2002-01-31 | Sumitomo Metal Ind Ltd | Method for producing ridging-resistant ferritic stainless steel |
| CN103173586A (en) * | 2013-04-15 | 2013-06-26 | 攀钢集团攀枝花钢铁研究院有限公司 | Method for lowering contents of oxygen and nitrogen in molten steel at smelting end in semisteel smelting converter |
| CN103627841A (en) * | 2013-11-01 | 2014-03-12 | 南京钢铁股份有限公司 | Control method for nitrogen content of molten steel of wear-resistant steel |
| CN108273971A (en) * | 2018-03-05 | 2018-07-13 | 首钢京唐钢铁联合有限责任公司 | A method of reducing casting process molten steel nitrogen increased amount |
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