CN115074490A - Converter steelmaking decarburization method - Google Patents
Converter steelmaking decarburization method Download PDFInfo
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- CN115074490A CN115074490A CN202210857136.9A CN202210857136A CN115074490A CN 115074490 A CN115074490 A CN 115074490A CN 202210857136 A CN202210857136 A CN 202210857136A CN 115074490 A CN115074490 A CN 115074490A
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- 238000000034 method Methods 0.000 title claims abstract description 44
- 238000009628 steelmaking Methods 0.000 title claims abstract description 33
- 238000005261 decarburization Methods 0.000 title claims abstract description 14
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 144
- 239000010959 steel Substances 0.000 claims abstract description 144
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 131
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 130
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 95
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 95
- 239000001301 oxygen Substances 0.000 claims abstract description 95
- 238000007664 blowing Methods 0.000 claims abstract description 89
- 239000007789 gas Substances 0.000 claims abstract description 37
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 16
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 claims description 12
- 229910052757 nitrogen Inorganic materials 0.000 claims description 8
- 229910052786 argon Inorganic materials 0.000 claims description 6
- 230000036284 oxygen consumption Effects 0.000 claims description 6
- 238000010079 rubber tapping Methods 0.000 claims description 4
- 230000000694 effects Effects 0.000 abstract description 6
- 230000002195 synergetic effect Effects 0.000 abstract description 4
- 229910045601 alloy Inorganic materials 0.000 description 31
- 239000000956 alloy Substances 0.000 description 31
- 238000003723 Smelting Methods 0.000 description 29
- 230000000052 comparative effect Effects 0.000 description 29
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 28
- 230000008569 process Effects 0.000 description 26
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 24
- 239000002893 slag Substances 0.000 description 23
- 238000007599 discharging Methods 0.000 description 22
- 239000000463 material Substances 0.000 description 18
- 239000000523 sample Substances 0.000 description 18
- 229910001209 Low-carbon steel Inorganic materials 0.000 description 11
- 238000009749 continuous casting Methods 0.000 description 10
- 238000005457 optimization Methods 0.000 description 10
- 238000007670 refining Methods 0.000 description 10
- 238000005096 rolling process Methods 0.000 description 10
- 239000004615 ingredient Substances 0.000 description 9
- 229910052742 iron Inorganic materials 0.000 description 7
- 229910052751 metal Inorganic materials 0.000 description 7
- 239000002184 metal Substances 0.000 description 7
- 238000006243 chemical reaction Methods 0.000 description 6
- 238000004519 manufacturing process Methods 0.000 description 6
- 239000002994 raw material Substances 0.000 description 6
- 235000008733 Citrus aurantifolia Nutrition 0.000 description 5
- 235000011941 Tilia x europaea Nutrition 0.000 description 5
- 229910000514 dolomite Inorganic materials 0.000 description 5
- 239000010459 dolomite Substances 0.000 description 5
- 239000012535 impurity Substances 0.000 description 5
- 239000004571 lime Substances 0.000 description 5
- 238000003756 stirring Methods 0.000 description 5
- 230000009467 reduction Effects 0.000 description 4
- 238000000926 separation method Methods 0.000 description 4
- MYMOFIZGZYHOMD-UHFFFAOYSA-N Dioxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 239000003795 chemical substances by application Substances 0.000 description 2
- 229910001882 dioxygen Inorganic materials 0.000 description 2
- 239000010931 gold Substances 0.000 description 2
- 229910052737 gold Inorganic materials 0.000 description 2
- CSJDCSCTVDEHRN-UHFFFAOYSA-N methane;molecular oxygen Chemical compound C.O=O CSJDCSCTVDEHRN-UHFFFAOYSA-N 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 229910000914 Mn alloy Inorganic materials 0.000 description 1
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 1
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- -1 aluminum-manganese-iron Chemical compound 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 238000009851 ferrous metallurgy Methods 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 125000004430 oxygen atom Chemical group O* 0.000 description 1
- 229910052698 phosphorus Inorganic materials 0.000 description 1
- 239000011574 phosphorus Substances 0.000 description 1
- 238000012797 qualification Methods 0.000 description 1
- 229910052717 sulfur Inorganic materials 0.000 description 1
- 239000011593 sulfur Substances 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
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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
- C21C7/068—Decarburising
-
- 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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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Manufacturing & Machinery (AREA)
- Carbon Steel Or Casting Steel Manufacturing (AREA)
Abstract
The invention discloses a converter steelmaking decarburization method, which comprises the steps of detecting component data of molten steel when a converter automatically makes steel to an end point, carrying out bottom blowing gas, judging carbon components of the molten steel and carbon components of a target steel grade, blowing oxygen when the difference between the carbon components of the molten steel and the carbon components of the target steel grade is more than or equal to 0.02%, and simultaneously adjusting the flow rate of the bottom blowing gas to discharge steel; when the difference between the carbon content of the molten steel and the carbon content of the target steel grade is less than 0.02%, the bottom-blowing gas flow rate is adjusted to discharge steel. The invention reduces the carbon content by using oxygen blowing and bottom blowing gas modes, reduces the difference value between the actual end point carbon and the target end point carbon by using oxygen blowing, subtracts 0.02 percent of carbon content, reduces the carbon content which is 0.02 percent higher than the target end point by using bottom blowing gas, and has synergistic promotion effect by using the oxygen blowing and bottom blowing gas modes.
Description
Technical Field
The invention relates to the technical field of converter steelmaking, in particular to a converter steelmaking decarburization method.
Background
The converter steelmaking is one of the key links in the steel industry, the production of the converter steelmaking is mainly an oxidation process of carbon reduction and temperature rise, oxygen is blown into a molten pool at a high speed to react with molten iron and release heat, so that the purposes of carbon reduction, temperature rise and reduction of the content of impurity elements such as phosphorus, sulfur and the like are achieved, and molten steel meeting the process requirements is finally obtained. The flow rate of oxygen during the blowing process is generally constant, so that the total amount of oxygen blown in plays an important role in controlling the blowing process, controlling the removal of impurity elements, the temperature rise of the molten bath and preventing the occurrence of splashing, and directly influencing the blowing effect of converter steelmaking and the quality of products.
In actual production, because measurement errors, equipment errors and raw material conditions cannot dynamically change along with the change of production conditions, errors occur when smelting is finished, and the errors are usually concentrated on carbon deviation or temperature deviation; when deviation occurs, dynamic adjustment is needed, if the carbon is high, oxygen is blown to remove the carbon, if the temperature is high, cold materials are needed to be added for cooling, and if the temperature is low, oxygen is continuously blown for heating.
According to the principle of ferrous metallurgy, carbon and oxygen in molten steel in a converter have an equilibrium constant, and when carbon is high, oxygen is low, and when carbon is low, oxygen is high.
The currently and generally adopted low-carbon steel smelting method comprises the following steps: blowing by an oxygen lance to ensure that the difference between the mass fraction of the end point carbon content of the converter and the target carbon of the steel grade is less than 0.01 percent, and then discharging molten steel to a ladle. In accordance with the above principles, lower end point carbons result in higher end point oxygen, and therefore, more deoxidizer and alloy must be added to remove the higher oxygen, resulting in increased costs for the alloy deoxidizer. Meanwhile, oxide inclusions generated by oxygen removal are correspondingly increased, which is unfavorable for the quality of molten steel.
Disclosure of Invention
In view of the prior art, the invention aims to provide a converter steelmaking decarburization method. In order to reduce the adverse effect of the overhigh terminal oxygen on the cost and the quality of the molten steel, the invention utilizes the relevant characteristics of carbon and oxygen to promote the further reaction of carbon and oxygen in the molten steel, effectively reduces the terminal carbon and oxygen of the converter and achieves the aim of reducing alloy and deoxidizer.
In order to achieve the purpose, the invention adopts the following technical scheme:
the invention provides a converter steelmaking decarburization method, which comprises the following steps:
when the converter automatically steelmaking reaches the end point, detecting the component data of the molten steel, simultaneously blowing gas at the bottom, judging the carbon component of the molten steel and the carbon component of the target steel grade, and when the difference between the carbon component of the molten steel and the carbon component of the target steel grade is more than or equal to 0.02%, blowing oxygen, and simultaneously adjusting the flow rate of the gas at the bottom blowing to discharge steel; when the difference between the carbon content of the molten steel and the carbon content of the target steel grade is less than 0.02%, the bottom-blowing gas flow rate is adjusted to discharge steel.
Preferably, the bottom blowing gas is nitrogen or argon while waiting for the display data, and the flow rate of the bottom blowing is 1000NM 3 The time of bottom blowing is 2-4 minutes.
Preferably, the amount of oxygen to be blown is an amount corresponding to an oxygen consumption obtained by subtracting 0.02% of carbon from a difference between the carbon content of molten steel and the carbon content of the target steel grade.
Preferably, the flow rate of the bottom-blowing device during oxygen blowing and steel tapping is 600NM 3 And/h, the bottom blowing gas is nitrogen or argon.
Preferably, the tapping time is 4-6 minutes.
The converter decarburization reaction steps are roughly as follows:
(1) the oxygen sprayed from the oxygen lance is absorbed on the gas-liquid interface of the impact pit and reacts with Fe in the molten steel to oxidize the Fe into FeO and Fe 2 O 3 ：
Fe+1/2O 2 →FeO (1)
2FeO+1/2O 2 →Fe 2 O 3 (2)
(2) The iron oxide migrates to the slag-gold interface, reacts with metallic Fe to produce FeO:
(Fe 2 O 3 )+[Fe]→3(FeO) (3)
(3) the generated FeO partially enters a metal phase according to a distribution law, part of the FeO is remained in a slag phase, the FeO remained in the slag phase participates in a slag-gold interface reaction, and the FeO entering the metal phase exists in the forms of iron atoms and oxygen atoms:
(FeO)→[FeO] (4)
(FeO)→[Fe]+[O] (5)
(4) oxygen entering the metal phase and carbon in the metal migrate to the CO bubble-metal interface;
(5) the [ C ] and the [ O ] which are transferred to the CO bubble-metal interface react to generate gaseous CO;
(6) CO bubbles grow and float upwards, pass through the metal phase and the slag phase in sequence and enter the furnace gas.
According to the carbon-oxygen balance, [ C ] x [ O ] -the equilibrium constant, the value of the equilibrium constant is 0.0020-0.0030, when the [ C ] content in the molten steel is low, [ O ] is increased, more deoxidizing agents and alloys must be added to remove higher oxygen, and the amount of the deoxidizing agents, the alloys and the oxides generated by oxygen is correspondingly increased, thus being unfavorable for the quality of the finished steel.
The bottom blowing nitrogen or argon improves stirring kinetic energy, promotes carbon to react with oxygen, reduces carbon while reducing oxygen, can ensure that the end point carbon is reduced within the range requirement, can reduce the end point oxygen, indirectly reduces deoxidizer and alloy reacting with oxygen, and reduces the amount of impurities produced.
The carbon content of the actual smelting end point is higher than that of the target end point in steel making, so the method reduces the carbon part of the actual smelting end point higher than the target end point by using oxygen blowing and bottom blowing, reduces the difference value between the actual end point carbon and the target end point carbon by using oxygen blowing, subtracts 0.02 percent of carbon content, and reduces the carbon content of the actual smelting end point carbon higher than the target end point by using bottom blowing. For example, the following steps are carried out: when the end point target carbon is 0.05%, the carbon at the actual end point of smelting is 0.10%, and it is necessary to blow an oxygen amount corresponding to 0.10% - (0.05% + 0.02%) to 0.03% carbon, and to reduce the carbon of 0.02% higher than the target end point carbon by accelerating the carbon-oxygen reaction by strong stirring of the bottom-blown gas.
When the difference between the carbon content of the molten steel and the carbon content of the target steel grade is less than 0.02%, carbon can be removed to meet the requirement when the component is waited, the steel placing condition can be met, meanwhile, the carbon content qualification rate is 100%, if the carbon difference exceeds 0.02%, the component is unqualified with probability, the higher the carbon content is, the higher the probability of the component unqualified is, the situation that the steel grade is changed into a plan or even is judged to be waste is easy to occur, and therefore, the difference between the carbon content of the molten steel and the carbon content of the target steel grade is determined to be 0.02%.
The invention relatively improves the carbon content at the molten steel smelting end point, fully utilizes the stirring energy, promotes the reaction of the C and the O, reduces the oxygen content in the molten steel, thereby reducing the addition of the deoxidizer and the alloy, reducing the production cost, correspondingly reducing harmful impurities generated by the deoxidizer, the alloy and the oxygen, and improving the quality of finished steel.
The invention has the beneficial effects that:
the invention reduces the carbon content by using the modes of oxygen blowing and bottom blowing, reduces the difference value between the actual end point carbon and the target end point carbon by using the oxygen blowing, subtracts 0.02 percent of the carbon content, reduces the carbon content which is 0.02 percent higher than the target end point by using the bottom blowing, and has the synergistic promotion effect by using the modes of the oxygen blowing and the bottom blowing.
The invention utilizes the relevant characteristics of carbon and oxygen, relatively improves the carbon content at the end point of molten steel smelting, utilizes stirring energy to promote the carbon and oxygen in the molten steel to further react, effectively reduces the end point carbon and oxygen of the converter, reduces the dosage of alloy and deoxidizer, and improves the quality of finished steel.
The method does not need additional materials, is convenient to operate, can effectively reduce the end point carbon and oxygen of the converter, and reduces the production cost. The method can be applied to any steel plant and has the advantages of wide application range, high popularization value and the like.
Drawings
FIG. 1: the invention relates to a process flow chart of automatic steelmaking of a converter;
FIG. 2: the schematic diagram of the converter steelmaking decarburization method of the invention;
shown in the figure: 1. the converter comprises a converter body, 2 oxygen lances, 3 furnace bottom, 4 bottom blowing devices and 5 sublance.
Detailed Description
It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the disclosure. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.
As described in the background art, the target carbon and end point carbon content of a steel grade is less than 0.01%, lower end point carbon results in higher end point oxygen, more deoxidizers and alloys are added, the cost is increased, and the quality of molten steel is not good due to the increase of oxides generated by oxygen removal. Based on the above, the invention provides a converter steelmaking decarburization method, which comprises the following steps:
(1) when the converter automatically steelmaking reaches the smelting end point, the oxygen lance stops supplying oxygen and rises to a point to be blown; a sublance of the converter enters molten steel from an inlet, and a probe of the sublance is lifted to a disengaging position after displaying data;
(2) in the process of waiting for the probe to display data in the step (1), the flow of the bottom blowing device is controlled to be 600NM 3 Adjusting the value of/h to 1000NM 3 And/h, the bottom blowing gas is nitrogen or argon, and the bottom blowing time is 2-4 minutes.
(3) Judging the data of the sublance probe and the carbon component of the target steel grade; the difference between the carbon content of the molten steel and the carbon content of the target steel grade is more than or equal to 0.02 percent, and the flow rate of the bottom blowing device is controlled to be 1000NM 3 Adjustment of/h to 600NM 3 Lowering the oxygen lance to blow oxygen continuously, wherein the blowing-in amount of the oxygen is the corresponding oxygen consumption amount which is obtained by subtracting 0.02 percent from the difference value of the carbon component of the molten steel and the target carbon component, raising the oxygen lance to a point to be blown after the oxygen blowing is finished, and discharging the molten steel to the point to be blownA ladle; the difference between the carbon content of the molten steel and the carbon content of the target steel grade is less than 0.02 percent, and the flow rate of the bottom blowing device is controlled to be 1000NM 3 Adjustment of/h to 600NM 3 And/h, discharging the molten steel to a ladle.
In order to make the technical solutions of the present application more clearly understood by those skilled in the art, the technical solutions of the present application will be described in detail below with reference to specific embodiments.
The test materials used in the examples of the present invention are all conventional in the art and commercially available.
Examples
The converter used in this example is a 120-ton top-bottom combined blown converter in Shandong Steel group type Steel works, and the process flow of automatic steelmaking by the converter is shown in FIG. 1. The raw materials used for smelting are molten iron and scrap steel, and the added materials are active lime, light-burned dolomite and sinter.
(1) When the converter automatically steelmaking reaches the smelting end point, the oxygen lance stops supplying oxygen and rises to a point to be blown; the sublance of the converter enters molten steel from a converter mouth and stays for 10 seconds, and a probe of the sublance is lifted to a separation position after displaying data;
(2) in the process of waiting for the probe to display data in the step (1), the flow of the bottom blowing device is controlled to be 600NM 3 Adjusting the value of/h to 1000NM 3 The bottom blowing gas is nitrogen, and the bottom blowing time is 3 minutes.
(3) Judging the data of the sublance probe and the carbon component of the target steel grade; the difference between the carbon content of the molten steel and the carbon content of the target steel grade is more than or equal to 0.02 percent, and the flow rate of the bottom blowing device is controlled to be 1000NM 3 Adjustment of/h to 600NM 3 And/h, lowering the oxygen lance to continuously blow oxygen, wherein the blowing-in amount of the oxygen is the corresponding oxygen consumption consumed by subtracting 0.02% from the difference value of the carbon component of the molten steel and the target carbon component, after the oxygen blowing is finished, raising the oxygen lance to a point to be blown, discharging the molten steel to a steel ladle, and during the discharging process, approximately 5 minutes are spent, during the period, firstly adding a deoxidizer, then adding alloy ingredients and slag materials to perform top slag optimization, and then, carrying out refining, continuous casting and rolling on the steel ladle to obtain the finished low-carbon steel. The difference between the carbon content of the molten steel and the carbon content of the target steel grade is less than 0.02 percent, and the flow rate of the bottom blowing device is controlled to be 1000NM 3 Adjusting/h to 600NM 3 And h, discharging the molten steel to a steel ladle, wherein the discharging process is about 5 minutes, during the period, firstly adding a deoxidizer, then adding alloy ingredients and slag materials for top slag optimization, and then performing refining smelting, continuous casting and rolling on the steel ladle to obtain the finished low-carbon steel.
Comparative example 1
The converter used in the comparative example is a 120-ton top-bottom combined blown converter in Shandong iron and steel group steel making plant, and the process flow of the converter for automatic steel making is shown in FIG. 1. The raw materials used for smelting are molten iron and scrap steel, and the added materials are active lime, light-burned dolomite and sinter.
(1) When the converter automatically steelmaking reaches the smelting end point, the oxygen lance stops supplying oxygen and rises to a point to be blown; the sublance of the converter enters molten steel from a converter mouth and stays for 10 seconds, and a probe of the sublance is lifted to a separation position after displaying data;
(2) and (3) in the process of waiting for the probe to display data in the step (1), no bottom blowing gas is carried out.
(3) Judging the data of the sublance probe and the carbon component of the target steel grade; the difference between the carbon content of the molten steel and the carbon content of the target steel grade is more than or equal to 0.02 percent, and the flow rate of the bottom blowing device is controlled to be 1000NM 3 Adjustment of/h to 600NM 3 And/h, lowering the oxygen lance to continuously blow oxygen, wherein the blowing-in amount of the oxygen is the corresponding oxygen consumption amount consumed by subtracting 0.02% from the difference value of the carbon component of the molten steel and the target carbon component, after the oxygen blowing is finished, raising the oxygen lance to a point to be blown, discharging the molten steel to a steel ladle, wherein the discharging process is about 5 minutes, during the period, firstly adding a deoxidizer, then adding alloy ingredients and slag materials to perform top slag optimization, then, performing smelting refining, continuous casting and rolling on the steel ladle to obtain the finished low-carbon steel. The difference between the carbon content of the molten steel and the carbon content of the target steel grade is less than 0.02 percent, and the flow rate of the bottom blowing device is controlled to be 1000NM 3 Adjustment of/h to 600NM 3 And h, discharging the molten steel to a steel ladle, wherein the discharging process is about 5 minutes, during the period, firstly adding a deoxidizer, then adding alloy ingredients and slag materials for top slag optimization, and then performing refining smelting, continuous casting and rolling on the steel ladle to obtain the finished low-carbon steel.
Comparative example 1 differs from the examples in that no bottom blowing gas, only oxygen gas was blown.
Comparative example 2
The converter used in the comparative example is a 120-ton top-bottom combined blown converter in Shandong Steel group type Steel works, and the process flow of the automatic steelmaking of the converter is shown in figure 1. The raw materials used for smelting are molten iron and scrap steel, and the added materials are active lime, light-burned dolomite and sinter.
(1) When the converter automatically steelmaking reaches the smelting end point, the oxygen lance stops supplying oxygen and rises to a point to be blown; the sublance of the converter enters molten steel from a converter mouth and stays for 10 seconds, and a probe of the sublance is lifted to a separation position after displaying data;
(2) in the process of waiting for the probe to display data in the step (1), the flow of the bottom blowing device is controlled to be 600NM 3 Adjusting the value of/h to 1000NM 3 The bottom blowing gas is nitrogen, and the bottom blowing time is 3 minutes.
(3) Judging the data of the sublance probe and the carbon component of the target steel grade; the difference between the carbon content of the molten steel and the carbon content of the target steel grade is more than or equal to 0.02 percent, oxygen is not blown, and the flow rate of a bottom blowing device is controlled to be 1000NM 3 Adjustment of/h to 600NM 3 And/h, discharging the molten steel to a steel ladle, wherein the discharging process is about 5 minutes, during the discharging process, firstly adding a deoxidizer, then adding alloy ingredients and slag materials to perform top slag optimization, and then performing refining smelting, continuous casting and rolling on the steel ladle to obtain a finished product of low-carbon steel. The difference between the carbon content of the molten steel and the carbon content of the target steel grade is less than 0.02 percent, and the flow rate of the bottom blowing device is controlled to be 1000NM 3 Adjustment of/h to 600NM 3 And h, discharging the molten steel to a steel ladle, wherein the discharging process is about 5 minutes, during the period, firstly adding a deoxidizer, then adding alloy ingredients and slag materials for top slag optimization, and then performing refining smelting, continuous casting and rolling on the steel ladle to obtain the finished low-carbon steel.
Comparative example 2 differs from the examples only in that gas was bottom blown and no oxygen was blown.
Comparative example 3
The converter used in the comparative example is a 120-ton top-bottom combined blown converter in Shandong Steel group type Steel works, and the process flow of the automatic steelmaking of the converter is shown in figure 1. The raw materials used for smelting are molten iron and scrap steel, and the added materials are active lime, light-burned dolomite and sinter.
(1) When the converter automatically steelmaking reaches the smelting end point, the oxygen lance stops supplying oxygen and rises to a point to be blown; the sublance of the converter enters molten steel from a converter mouth and stays for 10 seconds, and a probe of the sublance is lifted to a separation position after displaying data;
(2) and (3) in the process of waiting for the probe to display data in the step (1), no bottom blowing gas is carried out.
(3) Judging the data of the sublance probe and the carbon component of the target steel grade; the difference between the carbon content of the molten steel and the carbon content of the target steel grade is more than or equal to 0.02 percent, oxygen is not blown, and the flow rate of a bottom blowing device is controlled to be 1000NM 3 Adjusting/h to 600NM 3 And h, discharging the molten steel to a steel ladle, wherein the discharging process is about 5 minutes, during the period, firstly adding a deoxidizer, then adding alloy ingredients and slag materials for top slag optimization, and then performing refining smelting, continuous casting and rolling on the steel ladle to obtain the finished low-carbon steel. The difference between the carbon content of the molten steel and the carbon content of the target steel grade is less than 0.02 percent, and the flow rate of the bottom blowing device is controlled to be 1000NM 3 Adjustment of/h to 600NM 3 And h, discharging the molten steel to a steel ladle, wherein the discharging process is about 5 minutes, during the period, firstly adding a deoxidizer, then adding alloy ingredients and slag materials for top slag optimization, and then performing refining smelting, continuous casting and rolling on the steel ladle to obtain the finished low-carbon steel.
Comparative example 3 differs from the examples in that no gas was blown from the bottom and no oxygen was blown.
Comparative example 4
The converter used in the comparative example is a 120-ton top-bottom combined blown converter in Shandong Steel group type Steel works, and the process flow of the automatic steelmaking of the converter is shown in figure 1. The raw materials used for smelting are molten iron and scrap steel, and the added materials are active lime, light-burned dolomite and sinter.
(1) When the converter automatically steelmaking reaches the smelting end point, the oxygen lance stops supplying oxygen and rises to a point to be blown; a sublance of the converter enters molten steel from an inlet, and a probe of the sublance is lifted to a disengaging position after displaying data;
(2) in the process of waiting for the probe to display data in the step (1), the flow of the bottom blowing device is controlled to be 600NM 3 Adjusting the/h to 1000NM 3 The bottom blowing time is 3 minutes.
(3) Judging the data of the sublance probe and the carbon component of the target steel grade; the difference between the carbon content of the molten steel and the carbon content of the target steel grade is more than or equal to 0.01 percent, and the flow rate of the bottom blowing device is controlled to be 1000NM 3 Adjustment of/h to 600NM 3 And/h, lowering the oxygen lance to continuously blow oxygen, wherein the blowing-in amount of the oxygen is the corresponding oxygen consumption amount consumed by subtracting 0.01% from the difference value of the carbon component of the molten steel and the target carbon component, adding alloy components and slag materials to perform top slag optimization, and then performing refining smelting, continuous casting and rolling on the steel ladle to obtain the finished low-carbon steel.
The difference between the carbon content of the molten steel and the carbon content of the target steel grade is less than 0.01 percent, and the flow rate of the bottom blowing device is controlled to be 1000NM 3 Adjustment of/h to 600NM 3 And h, discharging the molten steel to a steel ladle, wherein the discharging process is about 5 minutes, during the period, firstly adding a deoxidizer, then adding alloy ingredients and slag materials for top slag optimization, and then performing refining smelting, continuous casting and rolling on the steel ladle to obtain the finished low-carbon steel.
The deoxidizers used in the above examples and comparative examples were aluminum-manganese-iron deoxidizers, and the alloy used was a medium-manganese alloy.
The amounts of the deoxidizers and alloys used in the examples and comparative examples are shown in Table 1.
TABLE 1
In example 1, the carbon content is reduced by blowing oxygen and bottom blowing gas, the blank control group of example 1 is comparative example 3, oxygen and bottom blowing gas are not blown, the amount of the deoxidizer used in example is reduced by 0.6kg/t and the amount of the alloy used is reduced by 0.18kg/t relative to that used in comparative example 3.
In comparative example 1, only oxygen gas was blown, but no gas was blown, and the amount of the deoxidizer used was reduced by 0.2kg/t and the amount of the alloy used was reduced by 0.08kg/t, relative to that used in comparative example 3. In comparative example 2, only bottom blowing gas was performed, and oxygen was not blown, and the amount of the deoxidizer used was reduced by 0.3kg/t and the amount of the alloy used was reduced by 0.03kg/t, relative to that used in comparative example 3. Comparative example 1+ comparative example 2 the amount of the deoxidizer used was reduced by 0.5kg/t and the amount of the alloy used was reduced by 0.11kg/t, relative to that used in comparative example 3. Comparative example 1+ comparative example 2 the amount of reduction of the deoxidizer and alloy in comparison with comparative example 3 was smaller than that in the examples, and therefore, the oxygen blowing and bottom blowing gas modes employed in the present invention had synergistic accelerating effects.
In comparative example 4, in which the amount of oxygen blown was 0.01% of the difference between the actual end point carbon content and the target end point carbon minus 0.01%, carbon higher than the target end point carbon was removed by means of bottom blowing, 0.3kg/t higher deoxidizer was added than in example, and 0.1kg/t higher alloy was used than in example. The example controlled the carbon content removed by the bottom-blowing gas to 0.02%, the comparative example 4 controlled the carbon content removed by the bottom-blowing gas to 0.01%, and the example used a lower amount of deoxidizer and alloy than the comparative example 4, which indicates that the oxygen content in the molten steel of the example was lower than that of the molten steel of the comparative example 4.
The method reduces the actual end point carbon content to be 0.02% higher than the target end point carbon content by oxygen blowing, removes 0.02% of carbon higher than the target end point carbon by using a bottom blowing gas mode, and has a synergistic promotion effect by the oxygen blowing and bottom blowing gas modes.
The invention relatively improves the carbon content at the molten steel smelting end point, fully utilizes stirring energy, promotes the reaction of carbon and oxygen, and reduces the oxygen content in the molten steel, thereby reducing the addition of the deoxidizer and the alloy, reducing the production cost, correspondingly reducing harmful impurities generated by the deoxidizer, the alloy and the oxygen, and improving the quality of finished steel.
The above description is only a preferred embodiment of the present application and is not intended to limit the present application, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the present application shall be included in the protection scope of the present application.
Claims (5)
1. A converter steelmaking decarburization method is characterized by comprising the following steps:
when the converter automatically steelmaking reaches the end point, detecting the component data of the molten steel, simultaneously blowing gas at the bottom, judging the carbon component of the molten steel and the carbon component of the target steel grade, and when the difference between the carbon component of the molten steel and the carbon component of the target steel grade is more than or equal to 0.02%, blowing oxygen, and simultaneously adjusting the flow rate of the gas at the bottom blowing to discharge steel; when the difference between the carbon content of the molten steel and the carbon content of the target steel grade is less than 0.02%, the bottom-blowing gas flow rate is adjusted to discharge steel.
2. The decarburization method for steelmaking using a converter as claimed in claim 1, wherein a bottom-blowing gas is used while waiting for the display data, the bottom-blowing gas being nitrogen or argon, and the flow rate of the bottom-blowing gas being 1000NM 3 The bottom blowing time is 2-4 minutes.
3. The decarburization method for steelmaking using a converter as claimed in claim 1, wherein the oxygen is blown in an amount corresponding to the difference between the carbon content of the molten steel and the carbon content of the target steel grade minus the oxygen consumption corresponding to 0.02% of the carbon consumption.
4. The decarburization method for steelmaking using a converter as claimed in claim 1, wherein the flow rate of the bottom blowing means is adjusted to 600NM during oxygen blowing and tapping 3 And/h, the bottom blowing gas is nitrogen or argon.
5. The decarburization method for steelmaking by a converter as claimed in claim 1, wherein the tapping time is 4 to 6 minutes.
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| JPS55161011A (en) * | 1979-05-31 | 1980-12-15 | Nippon Steel Corp | End point control method of oxygen converter |
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| CN112575137A (en) * | 2020-10-26 | 2021-03-30 | 邯郸钢铁集团有限责任公司 | Method for direct tapping during high-speed rail steel converter smelting |
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| JPS55161011A (en) * | 1979-05-31 | 1980-12-15 | Nippon Steel Corp | End point control method of oxygen converter |
| CN102344986A (en) * | 2011-11-11 | 2012-02-08 | 田陆 | Method, device and system for controlling steel-making endpoint of converter |
| CN104404197A (en) * | 2014-12-04 | 2015-03-11 | 北京首钢股份有限公司 | Method for reducing molten steel nitrogen in steelmaking link |
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| CN112575137A (en) * | 2020-10-26 | 2021-03-30 | 邯郸钢铁集团有限责任公司 | Method for direct tapping during high-speed rail steel converter smelting |
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