CN115232918A - Production control method suitable for low-carbon aluminum killed steel - Google Patents
Production control method suitable for low-carbon aluminum killed steel Download PDFInfo
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- CN115232918A CN115232918A CN202210861010.9A CN202210861010A CN115232918A CN 115232918 A CN115232918 A CN 115232918A CN 202210861010 A CN202210861010 A CN 202210861010A CN 115232918 A CN115232918 A CN 115232918A
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- 229910052799 carbon Inorganic materials 0.000 title claims abstract description 80
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 title claims abstract description 68
- 229910052782 aluminium Inorganic materials 0.000 title claims abstract description 68
- 229910000655 Killed steel Inorganic materials 0.000 title claims abstract description 20
- 238000000195 production control method Methods 0.000 title claims description 9
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 94
- 239000010959 steel Substances 0.000 claims abstract description 94
- 238000000034 method Methods 0.000 claims abstract description 58
- 230000008569 process Effects 0.000 claims abstract description 45
- 238000010079 rubber tapping Methods 0.000 claims abstract description 24
- 239000011572 manganese Substances 0.000 claims abstract description 18
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 claims abstract description 17
- 229910052748 manganese Inorganic materials 0.000 claims abstract description 17
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 claims description 68
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 63
- 229910052760 oxygen Inorganic materials 0.000 claims description 63
- 239000001301 oxygen Substances 0.000 claims description 63
- 238000007664 blowing Methods 0.000 claims description 48
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 42
- 229910052786 argon Inorganic materials 0.000 claims description 34
- DALUDRGQOYMVLD-UHFFFAOYSA-N iron manganese Chemical compound [Mn].[Fe] DALUDRGQOYMVLD-UHFFFAOYSA-N 0.000 claims description 22
- 229910000616 Ferromanganese Inorganic materials 0.000 claims description 21
- 238000005261 decarburization Methods 0.000 claims description 20
- 239000002245 particle Substances 0.000 claims description 19
- 238000004519 manufacturing process Methods 0.000 claims description 17
- 238000005275 alloying Methods 0.000 claims description 16
- 235000008733 Citrus aurantifolia Nutrition 0.000 claims description 14
- 235000011941 Tilia x europaea Nutrition 0.000 claims description 14
- 239000004571 lime Substances 0.000 claims description 14
- 238000009849 vacuum degassing Methods 0.000 claims description 12
- 229910045601 alloy Inorganic materials 0.000 claims description 11
- 239000000956 alloy Substances 0.000 claims description 11
- 239000002893 slag Substances 0.000 claims description 9
- 238000005070 sampling Methods 0.000 claims description 7
- 239000007789 gas Substances 0.000 claims description 6
- BRPQOXSCLDDYGP-UHFFFAOYSA-N calcium oxide Chemical compound [O-2].[Ca+2] BRPQOXSCLDDYGP-UHFFFAOYSA-N 0.000 claims description 4
- ODINCKMPIJJUCX-UHFFFAOYSA-N calcium oxide Inorganic materials [Ca]=O ODINCKMPIJJUCX-UHFFFAOYSA-N 0.000 claims description 4
- 239000000292 calcium oxide Substances 0.000 claims description 4
- GLUQASLPPGFZDK-UHFFFAOYSA-N [Ar++] Chemical compound [Ar++] GLUQASLPPGFZDK-UHFFFAOYSA-N 0.000 claims description 3
- 238000001514 detection method Methods 0.000 claims description 3
- ULGYAEQHFNJYML-UHFFFAOYSA-N [AlH3].[Ca] Chemical compound [AlH3].[Ca] ULGYAEQHFNJYML-UHFFFAOYSA-N 0.000 claims description 2
- 238000012790 confirmation Methods 0.000 claims description 2
- 230000001276 controlling effect Effects 0.000 claims 7
- RQMIWLMVTCKXAQ-UHFFFAOYSA-N [AlH3].[C] Chemical compound [AlH3].[C] RQMIWLMVTCKXAQ-UHFFFAOYSA-N 0.000 claims 5
- 230000001105 regulatory effect Effects 0.000 claims 1
- 238000003723 Smelting Methods 0.000 abstract description 21
- 239000002131 composite material Substances 0.000 abstract description 2
- 238000009529 body temperature measurement Methods 0.000 description 9
- 238000012545 processing Methods 0.000 description 8
- 230000000694 effects Effects 0.000 description 4
- 238000007670 refining Methods 0.000 description 4
- 238000009628 steelmaking Methods 0.000 description 4
- 238000003756 stirring Methods 0.000 description 4
- 238000009749 continuous casting Methods 0.000 description 3
- 230000009286 beneficial effect Effects 0.000 description 2
- 230000002349 favourable effect Effects 0.000 description 2
- 239000003607 modifier Substances 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 238000009489 vacuum treatment Methods 0.000 description 2
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 1
- 229910000640 Fe alloy Inorganic materials 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 238000004364 calculation method Methods 0.000 description 1
- 239000003575 carbonaceous material Substances 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 230000003749 cleanliness Effects 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 238000007872 degassing Methods 0.000 description 1
- 238000005265 energy consumption Methods 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 230000014759 maintenance of location Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000011112 process operation Methods 0.000 description 1
- 238000005086 pumping Methods 0.000 description 1
- 230000001020 rhythmical effect Effects 0.000 description 1
- 238000009865 steel metallurgy Methods 0.000 description 1
- 239000002436 steel type Substances 0.000 description 1
- 239000013589 supplement Substances 0.000 description 1
Classifications
-
- 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
- C21C7/06—Deoxidising, e.g. killing
-
- 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
- C21C7/0006—Adding metallic additives
-
- 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
- C21C7/10—Handling in a vacuum
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Treatment Of Steel In Its Molten State (AREA)
Abstract
The invention discloses a smelting process of low-carbon aluminum killed steel (LCAK steel). A composite 'semi-deoxidation' process is carried out by adding manganese and aluminum in the tapping process of a converter, so that the OB rate of vacuum smelting can be effectively reduced.
Description
Technical Field
The invention belongs to the technical field of steel metallurgy and steelmaking, and particularly relates to a production control method suitable for low-carbon aluminum killed steel.
Background
The low-carbon aluminum killed steel of the process route of 'converter-RH (RH refining is fully called as RH vacuum circulation degassing refining method, the processing and continuous casting are carried out in a vacuum degassing device', the carbon content of the tapped steel is within 0.03-0.06 percent, a full deoxidation process mode in the converter tapping process is adopted, [ ALs ] is adjusted to be 0.035-0.55 percent, and in order to ensure that the target component of [ C ] is qualified before RH smelting, complicated processes of removing [ ALs ] by oxygen blowing, then decarbonizing, deoxidizing, adjusting the temperature, increasing carbon and alloying are adopted. The process has the problems of higher requirement on the blowing end temperature of the converter, longer RH processing time, large temperature drop in the early decarburization molten steel process, unfavorable cost reduction caused by firstly removing the [ ALs ] and the [ C ] and then adding carbon, and the like, and is not favorable for reducing the smelting cost and the high-efficiency production of steelmaking.
Chinese patent CN110484681A discloses a production method of low-carbon low-silicon aluminum killed molten steel, the molten steel is not deoxidized in the tapping process, and high-carbon ferromanganese is added in the tapping process; after tapping is finished, adding a ladle slag modifier into the ladle slag surface to modify the ladle slag; the molten steel is subjected to RH vacuum treatment, carbonaceous materials are added in batches for carbon deoxidation, aluminum addition final deoxidation and alloy fine adjustment are carried out after the oxygen activity is controlled to be below 50ppm, and the molten steel is discharged; and adding a ladle slag modifier into the ladle after the station to modify the ladle slag. The smelting method of the low-carbon aluminum killed steel ensures the stability of the whole process production flow and improves the cleanliness of molten steel, but requires higher control temperature of a converter end point and higher RH entering temperature, has longer RH treatment period, increases the production cost and is not beneficial to efficient production of steelmaking.
Disclosure of Invention
1. Problems to be solved
The invention aims to provide a steel smelting process which reduces energy consumption and improves efficiency;
the invention also aims to provide a smelting process which can reduce the tapping temperature of the converter and shorten the vacuum treatment time by controlling the charging time and the charging sequence in a rhythmic manner.
2. Technical scheme
In order to solve the problems, the technical scheme adopted by the invention is as follows:
a production control method suitable for low-carbon aluminum killed steel,
the method comprises the following steps:
semi-deoxidizing molten steel in the process of tapping from a converter, wherein the molten steel has an initial oxygen content not lower than 400 ppm;
the tapped molten steel is treated in a vacuum degassing device;
wherein,
the semi-deoxidation comprises the following steps:
adding high-carbon manganese to adjust the manganese content and the oxygen content in the molten steel;
adding aluminum to adjust the oxygen content and top slag oxidability in molten steel;
adding calcium oxide to adjust the calcium-aluminum ratio of the top slag;
after the semi-deoxidation is finished, controlling the residual oxygen content in the molten steel to be not less than 30% of the initial oxygen content; it is further preferable to control the residual oxygen content in the molten steel to not less than 40% of the initial oxygen content.
It should be noted that, in the conventional blowing process, the carbon content of the low-carbon aluminum killed steel in the process route of converter-RH-continuous casting is within 0.07%, and the complex smelting process that the steel is not deoxidized in the tapping process of the converter, the molten steel is subjected to oxygen-retaining RH treatment, and is completely decarburized and then deoxidized, and finally carburized and alloyed is performed is often adopted. The process has the problems of higher requirement on the blowing end temperature of the converter, longer RH processing time, large temperature drop in the early decarburization molten steel process, unfavorable cost reduction during decarburization and recarburization, and the like, and is not favorable for reducing the smelting cost and efficient production of steelmaking.
The technical scheme of the invention breakthroughs the 'semi-deoxidation' treatment on the molten steel in the converter tapping process, the deoxidation amount reaches 50-70%, and the temperature of the converter end point can be reduced by 5-15 ℃ compared with the temperature of the converter end point in the traditional process.
Further, during tapping of the molten steel from the converter, high-carbon manganese addition and aluminum addition are performed, and the residual oxygen content in the molten steel after the semi-deoxidation is controlled to be 30-50%, more preferably 40-55% of the initial oxygen content. The general full-deoxidation steel grade has requirements on the adding sequence of high-carbon manganese and aluminum, and the semi-deoxidation in the method does not need to divide the adding sequence of high-carbon ferromanganese and deoxidation aluminum particles into front and back, so that the operation of production and smelting operators is facilitated (the process operation is reduced).
It should be noted that if the oxygen content in the molten steel is reduced too much during this step, a large amount of aluminum is consumed, and if it is too low, the OB rate (the OB rate means the oxygen blowing rate during RH treatment) is increased.
Furthermore, the adding amount of the aluminum is 0.30-0.90kg/t per ton of steel. The aluminum is preferably used for the deoxidation treatment,
the regression of the big data shows that 100ppm of oxygen can be removed from every 50kg of aluminum particles.
Further, adding high-carbon manganese into the high-carbon manganese-iron alloy; the addition amount of the ferromanganese alloy is comprehensively considered according to the manganese content required by the target steel grade and the high-carbon manganese carburetion amount; generally, the high-carbon ferromanganese alloy is selected, and the adding amount of the high-carbon ferromanganese alloy is 1.5-1.7kg/t per ton of steel. And for the high-carbon ferromanganese alloy, the manganese is increased by 0.01 percent when 45kg/t of high-carbon ferromanganese is added into molten steel;
furthermore, lime is selected to add the calcium oxide, and the adding amount of the lime is 1.8-2.8kg/t per ton of steel.
Further, the carbon content [ C ] of the target steel grade is determined] Target ；
Determination of the carbon content [ C ] of the target Steel grade] Target ；
Before the molten steel enters a vacuum degassing device for treatment, the temperature measurement and sampling detection of the molten steel are carried out to obtain the carbon content [ C ] of the molten steel] Blowing argon (ii) a And oxygen content [ O] Blowing argon (ii) a (this step can be carried out by means of an argon blowing station)
Confirmation of [ C] Target And [ C] Blowing argon The relation satisfied between the two is used for carrying out the corresponding vacuum carbon retaining operation;
wherein [ C ] is] Target Has [ C ]] Target lower limit value 、[C] Target value And [ C] Target upper limit value Said [ C ]] Target lower limit value <[C] Target value <[C] Target upper limit value ；
Said [ C ]] Target And [ C] Blowing argon The satisfied relationship therebetween has:<
[C] blowing argon ≤[C] Target value Or is or
[C] Blowing argon ＞[C] Target upper limit value 。
Wherein [ C ] as described herein] Target value To refer to the best value for the best effect.
Further, the molten steel is treated in a vacuum degassing apparatus with an argon gas flow rate of 120-150Nm 3 H; at the same time, oxygen content [ O ] is carried out] RH station And (4) oxygen determination detection.
Further, when the molten steel is processed in a vacuum degassing apparatus,
when molten steel is treated in a vacuum degassing apparatus,
if [ C ]] Blowing argon ≤[C] Target value Then vacuum is applied to < 450mbar according to [ O ]] RH The result is to determine the amount of aluminum required for deoxidation (total deoxidation), and from the amount of aluminum required for alloying, to determine the total amount of aluminum required to be added.
Further, when the molten steel is processed in a vacuum degassing apparatus, [ C ]] Blowing argon ＞[C] Target upper limit value Then, then
First, decarburization treatment is carried out to [ C ] using oxygen in molten steel] Blowing argon ≤[C] Target upper limit value The decarburization oxygen demand is at least ([ C)] Blowing argon -[C] Target value ) 100 (the formula results ensure the oxygen content consumed for decarburization);
then, vacuumizing to less than or equal to 450mbar, adding aluminum for deoxidation treatment, wherein the adding amount of aluminum particles is ([ O ]] RH station entering -([C] Argon blowing station -[C] Target value ) 100)/2, measuring the temperature and determining the oxygen when the CO curve is less than or equal to 15 percent, and adding the deoxidized and alloyed aluminum according to the oxygen determination result.
It should be noted here that the number of the components,
1) In the case where the oxygen content [ O ] to be removed is known, the formula for calculating the amount of aluminum required is as follows:
① basic reaction formula 2Al +3[ O ] for calculation]＝Al 2 O 3 ；
② At molten steel, oxygen content [ O ] in molten steel]B ppm, the total oxygen content of the steel liquid is as follows:
A t×1000×0.0B％＝Y(kg)；
③ calculating the adding amount Q kg of aluminum: (2 × 27)/(3 × 16) = Q/Y.
2) Per 100PPM of [ O ] in vacuum] RH Will consume 0.01% of C]Therefore, the amount of oxygen consumed in decarburization of molten steel is ([ C ]] Blowing argon -[C] Target value )*100；
During tapping of the converter, e.g. [ C ]]Exceeding the upper limit of the desired carbon content [ C ]] Target upper limit value Namely, the carbon retention operation in a vacuum state is adopted according to a formula. On the contrary, the tapping process of the converter is as shown in [ C ]]Not exceeding or falling below [ C] Target value Then deoxidation and carbon supplement treatment are carried out.
Further, after the aluminum is added, the circulation time is 3min;
then adding other alloys for component adjustment according to the component standard of the target steel grade,
and then, breaking the air after the circulation time is more than or equal to 4min, wherein the air breaking means the change of pressure, the pressure in the vacuum state is about 0.26mbar generally, and after the circulation time is more than or equal to 4min, opening an air breaking valve to break the air, and the pressure is restored to the normal pressure state, namely, one atmospheric pressure of 1013.25mbar.
3. Advantageous effects
Compared with the prior art, the invention has the beneficial effects that:
(1) According to the production control method suitable for low-carbon aluminum killed steel, manganese and aluminum are added in the converter tapping process to carry out a composite semi-deoxidation process, so that the OB rate of vacuum smelting can be effectively reduced.
(2) The production control method suitable for the low-carbon aluminum killed steel provided by the invention has the advantages that carbon is remained in the RH vacuum state, and whether the RH needs to be decarburized is determined according to the analysis result of the carbon content of the sample in the argon blowing station. If not decarburize, directly adding aluminum for deoxidation and then alloying; if decarburization is needed, incomplete decarburization is carried out, RH first-step pre-deoxidation content is calculated according to the allowable amount range and the optimal target value of carbon content and the carbon content of an argon blowing station, partial oxygen is reserved for decarburization to reach the target value of the carbon component of the steel grade, and recarburization is not needed during alloying. The RH smelting period is greatly shortened, the requirements of the end point temperature of the converter and the RH station-entering temperature are lowered, the production cost is greatly lowered, and the production efficiency is improved;
compared with the traditional smelting process of not deoxidizing in the converter tapping process, the smelting process of completely decarbonizing and deoxidizing molten steel after oxygen-retaining RH treatment and finally recarburizing and alloying reduces the temperature drop of the converter end point by 5-15 ℃, the RH treatment time is averagely 13min and is averagely reduced by 7min compared with the prior process, the production efficiency is greatly improved, the smelting time is shortened, and the production cost is greatly reduced by reducing the temperature.
Detailed Description
The present invention is further illustrated by the following specific examples, which are not intended to limit the invention in any way. Reagents, methods and apparatus used in the present invention are conventional in the art unless otherwise specified;
the essential features and the remarkable effects of the present invention can be obtained from the following examples, which are a part of the examples of the present invention, but not all of them, and therefore they do not limit the present invention, and those skilled in the art should make some insubstantial modifications and adjustments according to the contents of the present invention, and fall within the scope of the present invention.
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 invention belongs; as used herein, the term and/or includes any and all combinations of one or more of the associated listed items.
As used herein, the term "not less than" or "not more than" is intended to include within its scope such a term as "the amount of a substance is not less than 100ppm", and is intended to mean "the amount of the substance may be 100ppm, or more than 100ppm".
The invention provides a high-efficiency smelting process of low-carbon aluminum killed steel, which relates to a smelting process of steel seeds and comprises the following steps: 300tBOF (300 ton converter) → CT (argon blowing station) → RH (RH vacuum refining furnace) → CC (continuous casting machine), including the steps of:
(1) The strong bottom blowing mode is adopted in the later stage of converter blowing, the stirring of a molten pool is enhanced, and the terminal carbon and terminal oxygen content [ O ] of the converter is reduced; the end point temperature of the converter is 1630-1645 ℃;
(2) Sequentially adding manganese (preferably high-carbon ferromanganese) → aluminum (preferably deoxidized aluminum particles) → lime in the converter tapping process, wherein the adding amount of the lime is 1.8-2.8kg/t per ton of steel; the high-carbon ferromanganese is added according to the lower limit of the control of the manganese content of the actual smelting steel type, the manganese is increased by 0.01 percent every 45kg/t of the high-carbon ferromanganese, and the adding amount of aluminum particles is 0.30-0.90kg/t of each ton of steel; for example, according to a 300 ton converter, as shown in table 1 below, an exemplary reference amount of the metallic aluminum added to the corresponding table according to the oxygen content [ O ] at the tapping end point of the converter is as follows (the numerical value of the added amount of the aluminum in the following table can also be adjusted according to the actual specific oxygen content):
| [O]/ppm | ＜400 | 400≤[O]＜550 | 550≤[O]＜650 | 650≤[O]＜750 | 750≤[O]＜850 | 850≤[O]＜950 |
| aluminum addition/Kg | 100 | 130 | 150 | 180 | 220 | 280 |
(3) Covering the ladle after temperature measurement and sampling in an argon blowing station, and transferring to RH for refining;
(4) RH temperature measurement sampling of getting into the station, whole adoption depth processing mode promotes gas flow 120-150Nm3/h, stays the carbon operation as follows: (1) if [ C ]] Argon blowing station ≤[C] Target upper limit value Decarburization is not needed, when RH starts to be processed and vacuumized to be less than or equal to 450mbar, the amount of aluminum needed by deoxidation and alloying is directly added according to the oxygen determination result, the rest of alloy is added after the circulation time is 3min after the aluminum particles are added, the target value is adjusted, and the space is broken after the circulation time is more than or equal to 4min after alloying; (2) if [ C ]]Argon blowing station > [ C ]] Target upper limit value Then, the vacuum is required to reserve oxygen for decarburization, and the reserved decarburization oxygen amount is ([ C ]]Argon blowing station [ C]Target value) 100. When RH treatment is started and vacuum pumping is carried out to be less than or equal to 450mbar, pre-deoxidation aluminum particles are added, and the oxygen content of 50kg aluminum particles is regressed to remove 100ppm oxygen content according to big data, so that the adding amount of the aluminum particles is ([ O ] ]RH station -([C] Argon blowing station -[C] Target value ) 100)/2, measuring the temperature and determining the oxygen when the CO curve is less than or equal to 15 percent, adding deoxidation and alloying aluminum according to the oxygen determination result, adding the rest alloys after 3min of circulation time after aluminum particles are added, adjusting to a target value, and breaking the air after the circulation time is more than or equal to 4min after alloying.
The RH arrival temperature is 1594 ℃; the RH leaving temperature is 1586 ℃;
the invention is further described with reference to specific examples.
Example 1
The process flow of smelting a steel seed DC01 is 300tBOF → CT → RH → CC, and comprises the following steps:
(1) In the later stage of converter blowing, a strong bottom blowing mode is adopted to strengthen the stirring of a molten pool, the end point temperature of the converter is 1646 ℃, the end point oxygen is 430ppm, and the end point carbon is 0.028%;
(2) High-carbon ferromanganese → deoxidized aluminum particles → lime is added in sequence during the tapping process of the converter;
specifically, when the molten steel tapping from the converter reaches 30 +/-5% of the total amount of the molten steel, high-carbon ferromanganese is added into the molten steel; when the molten steel amount of converter tapping reaches 75 +/-5% of the total amount of the molten steel, adding deoxidized aluminum particles into the molten steel; finally, lime is added;
wherein the addition of lime is 2.63kg/t per ton of steel, the addition of high-carbon ferromanganese is 1.17kg/t per ton of steel, and the addition of aluminum particles is 0.42kg/t per ton of steel;
(3) The temperature of the argon blowing station is measured to be 1620 ℃, the oxygen content is 229ppm, and the carbon content is 0.024%;
(4) RH station entering temperature measurement sampling is carried out, a deep processing mode is adopted in the whole process, the gas flow is improved by 140Nm & lt 3 & gt/h, decarburization is judged to be not needed according to the DC01 carbon content target of 0.020%, the scheme of the operation (1) is adopted, RH station entering temperature measurement is carried out at 1597 ℃, oxygen is determined by 220ppm, 0.93kg/t of aluminum is calculated, medium carbon ferromanganese is added after aluminum is added for 4min to adjust Mn to a target value, and the process is circulated for 5min to break empty after alloying; the RH end point carbon content is 0.0210%, the other components are all qualified, and the RH exit temperature is 1586 ℃; RH treatment time 12min.
Example 2
The process flow 300tBOF → CT → RH → CC of the smelting steel variety DX51D comprises the following steps:
(1) A strong bottom blowing mode is adopted in the later stage of converter blowing, the stirring of a molten pool is enhanced, the end point temperature of the converter is 1640 ℃, the end point oxygen is 412ppm, and the end point carbon is 0.046%;
(2) High-carbon ferromanganese → deoxidized aluminum particles → lime is added in sequence during the tapping process of the converter;
specifically, when the molten steel tapping from the converter reaches 30 +/-5% of the total amount of the molten steel, high-carbon ferromanganese is added into the molten steel; when the amount of the molten steel tapped by the converter reaches 75 +/-5 percent of the total amount of the molten steel, adding deoxidized aluminum particles into the molten steel; finally, lime is added;
wherein the addition of lime is 2.51kg/t per ton of steel, the addition of high-carbon ferromanganese is 1.17kg/t per ton of steel, and the addition of aluminum particles is 0.41kg/t per ton of steel;
(3) Measuring the temperature of an argon blowing station at 1609 ℃, wherein the oxygen content is 300ppm, and the carbon content is 0.037%;
(4) RH station entering temperature measurement sampling adopts a deep processing mode in the whole process, the gas flow is improved by 130Nm & lt 3 & gt/h, decarburization is judged to be needed according to the condition that the carbon content target of DX51D is 0.025%, the scheme of the operation (2) is adopted, RH station entering temperature measurement is 1596 ℃, oxygen is determined by 313ppm, 0.32kg/t of pre-deoxidized aluminum is calculated, circulation is carried out for 3min after aluminum is added, a CO curve is 13.4%, oxygen is determined by 117ppm, deoxidation and alloying are added by 0.83kg/t, mn is adjusted to the target value by medium carbon ferromanganese after circulation is carried out for 3min, circulation is carried out for 4min after alloying, the RH terminal carbon content is 0.0255%, the other components are all qualified, the RH station leaving temperature is 1584 ℃, and the RH processing time is 14min.
Comparative example 1
Smelting a steel seed SPHC, wherein the target carbon is 0.05 percent, and the process flow is 300tBOF → CT → RH → CC, and comprises the following steps:
(1) A strong bottom blowing mode is adopted in the later stage of converter blowing, the stirring of a molten pool is enhanced, the end temperature of the converter is 1667 ℃, the end oxygen is 447ppm, and the end carbon is 0.032%;
(2) Adding lime in the converter tapping process, wherein the adding amount of the lime is 3.1kg/t per ton of steel; at this stage, no C-Mn-Fe and Al particles are added;
(3) The temperature of an argon blowing station is 1634 ℃, the oxygen content is 497ppm, and the carbon content is 0.024%;
(4) RH station entering temperature measurement sampling adopts a shallow processing mode in the whole process, the gas flow is improved by 140Nm3/h, the RH station entering temperature measurement is 1616 ℃, the oxygen determination is 481ppm, RH decarburization is carried out for 9min, the carbon content is 50-100ppm after decarburization is finished, 0.96kg/t of deoxidation and alloying aluminum is added according to the oxygen determination result after decarburization is finished, 0.32kg/t and 2.38kg/t of alloying carbon powder and medium carbon ferromanganese are respectively added after the aluminum particles are added for 4min in a circulation mode, 3.8kg/t of scrap steel is obtained, and the circulation time is 5min after alloying for emptying; the RH end point carbon content is 0.0496%, the other components are all qualified, and the RH exit temperature is 1586 ℃; RH treatment time 20min.
Claims (10)
1. A production control method suitable for low-carbon aluminum killed steel, which is characterized in that,
the method comprises the following steps:
semi-deoxidizing molten steel in the process of tapping from a converter, wherein the molten steel has an initial oxygen content of more than or equal to 400 ppm;
the tapped molten steel is treated in a vacuum degassing device;
wherein,
the semi-deoxidation comprises the following steps:
adding high-carbon manganese to adjust the manganese content and the oxygen content in the molten steel;
adding aluminum for regulating the oxygen content and the top slag oxidability in molten steel;
adding calcium oxide to adjust the calcium-aluminum ratio of the top slag;
after the semi-deoxidation is finished, the residual oxygen content in the molten steel is controlled to be not less than 40% of the initial oxygen content.
2. The method for controlling production of low carbon aluminum killed steel as claimed in claim 1,
and in the process of tapping the molten steel from the converter, adding high-carbon manganese and aluminum, and controlling the residual oxygen content in the molten steel after the semi-deoxidation to be 40-55% of the initial oxygen content.
3. The method as claimed in claim 2, wherein the amount of aluminum added is 0.30-0.90kg/t per ton of steel, calculated from the oxygen content of the molten steel at the end of the converter.
4. The method for controlling production of low carbon aluminum killed steel as claimed in claim 3,
selecting a high-carbon ferromanganese alloy to add the high-carbon manganese; the addition amount of the high-carbon ferromanganese alloy is 1.5-1.7kg/t per ton of steel.
5. The method for controlling production of low carbon aluminum killed steel as claimed in claim 4,
lime is selected to add the calcium oxide, and the adding amount of the lime is 1.8-2.5kg/t per ton of steel.
6. The method for controlling production of low carbon aluminum-killed steel as claimed in claim 5,
determining the carbon content [ C ] of the target steel grade] Target ；
Before the molten steel enters a vacuum degassing device for treatment,
measuring the temperature of the molten steel, sampling and detecting to obtain the carbon content C of the molten steel] Blowing argon (ii) a And oxygen content [ O] Blowing argon ；
Confirmation of [ C] Target And [ C] Blowing argon The relation is satisfied, so as to carry out corresponding vacuum carbon retaining operation;
wherein [ C ] is] Target Has [ C ]] Target lower limit value 、[C] Target value And [ C] Target upper limit value Said [ C ]] Target lower limit value <[C] Target value <[C] Target upper limit value ；
Said [ C] Target And [ C] Blowing argon The satisfied relationship therebetween has:<
[C] blowing argon ≤[C] Target value Or is or
[C] Blowing argon ＞[C] Target upper limit value 。
7. The method for controlling production of low carbon aluminum killed steel as claimed in claim 6,
treating the molten steel in a vacuum degassing device, wherein the flow rate of argon gas is 120-150Nm3/h; oxygen content [ O ] is carried out] RH And (4) oxygen determination detection.
8. The production control method for a low carbon aluminum-killed steel as claimed in claim 7,
when molten steel is treated in a vacuum degassing apparatus,
if [ C ]] Blowing argon ≤[C] Target value Then, vacuum is applied to < 450mbar according to [ O ]] RH The result is to determine the deoxidation stationThe amount of aluminum required is determined by the total amount of aluminum required to be added according to the amount of aluminum required for alloying.
9. The method for controlling production of low carbon aluminum-killed steel as claimed in claim 7,
when molten steel is processed in a vacuum degassing apparatus, [ C ]] Blowing argon ＞[C] Target upper limit value Then, then
First, decarburization treatment is carried out to [ C ] using oxygen in molten steel] Blowing argon ≤[C] Target upper limit value The oxygen content of the molten steel after decarburization is ([ C ]] Blowing argon -[C] Target value )*100；
Then, vacuumizing to less than or equal to 450mbar, adding aluminum for deoxidation treatment, wherein the adding amount of aluminum particles is ([ O ]] RH station entering -([C] Argon blowing station -[C] Target value ) 100)/2, measuring the temperature and determining the oxygen when the CO curve is less than or equal to 15 percent, and adding deoxidized and alloyed aluminum according to the oxygen determination result.
10. The production control method for low carbon aluminum killed steel as claimed in claim 8 or 9,
after the aluminum is added, the circulation time is 3min;
then, adding other alloys for component adjustment according to the component standard of the target steel grade;
then, the cycle time is more than or equal to 4min;
and finally, breaking the air to a normal pressure state by negative pressure.
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| CN115572793A (en) * | 2022-11-09 | 2023-01-06 | 马鞍山钢铁股份有限公司 | RH smelting method and system for low-carbon aluminum killed steel |
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