CN115232918B - 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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- CN115232918B CN115232918B CN202210861010.9A CN202210861010A CN115232918B CN 115232918 B CN115232918 B CN 115232918B CN 202210861010 A CN202210861010 A CN 202210861010A CN 115232918 B CN115232918 B CN 115232918B
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- 229910052799 carbon Inorganic materials 0.000 title claims abstract description 77
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 title claims abstract description 72
- 229910052782 aluminium Inorganic materials 0.000 title claims abstract description 71
- 229910000655 Killed steel Inorganic materials 0.000 title claims abstract description 15
- 238000000195 production control method Methods 0.000 title claims description 11
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 90
- 239000010959 steel Substances 0.000 claims abstract description 90
- 238000000034 method Methods 0.000 claims abstract description 52
- 238000010079 rubber tapping Methods 0.000 claims abstract description 23
- 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 74
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 62
- 229910052760 oxygen Inorganic materials 0.000 claims description 62
- 239000001301 oxygen Substances 0.000 claims description 62
- 238000007664 blowing Methods 0.000 claims description 48
- 229910052786 argon Inorganic materials 0.000 claims description 37
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 34
- 238000011282 treatment Methods 0.000 claims description 27
- 229910000616 Ferromanganese Inorganic materials 0.000 claims description 23
- DALUDRGQOYMVLD-UHFFFAOYSA-N iron manganese Chemical compound [Mn].[Fe] DALUDRGQOYMVLD-UHFFFAOYSA-N 0.000 claims description 23
- 239000002245 particle Substances 0.000 claims description 19
- 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
- 229910045601 alloy Inorganic materials 0.000 claims description 12
- 239000000956 alloy Substances 0.000 claims description 12
- 238000005275 alloying Methods 0.000 claims description 12
- 238000009529 body temperature measurement Methods 0.000 claims description 9
- 239000002893 slag Substances 0.000 claims description 9
- 238000009849 vacuum degassing Methods 0.000 claims description 9
- 239000007789 gas Substances 0.000 claims description 6
- 238000005070 sampling Methods 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
- 238000001514 detection method Methods 0.000 claims description 4
- 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
- 230000001590 oxidative effect Effects 0.000 claims description 2
- 238000003723 Smelting Methods 0.000 abstract description 21
- 239000002131 composite material Substances 0.000 abstract description 2
- 238000005261 decarburization Methods 0.000 description 17
- 238000004519 manufacturing process Methods 0.000 description 11
- 238000009628 steelmaking Methods 0.000 description 4
- 238000003756 stirring Methods 0.000 description 4
- 230000000694 effects Effects 0.000 description 3
- 239000004411 aluminium Substances 0.000 description 2
- 238000004364 calculation method Methods 0.000 description 2
- 238000009749 continuous casting Methods 0.000 description 2
- 230000001276 controlling effect Effects 0.000 description 2
- 238000005262 decarbonization Methods 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 239000003607 modifier Substances 0.000 description 2
- 238000007670 refining Methods 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 238000009489 vacuum treatment Methods 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 1
- 230000006978 adaptation Effects 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000033228 biological regulation Effects 0.000 description 1
- 239000003575 carbonaceous material Substances 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
- 238000005265 energy consumption Methods 0.000 description 1
- 238000009851 ferrous metallurgy Methods 0.000 description 1
- 230000014759 maintenance of location Effects 0.000 description 1
- 238000011112 process operation Methods 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 238000004904 shortening Methods 0.000 description 1
- 239000002436 steel type Substances 0.000 description 1
- 230000001502 supplementing effect Effects 0.000 description 1
- 238000012546 transfer Methods 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), wherein manganese and aluminum are added in the tapping process of a converter to carry out a composite semi-deoxidization process, so that the OB ratio of vacuum smelting can be effectively reduced.
Description
Technical Field
The invention belongs to the technical field of ferrous metallurgy steelmaking, and particularly relates to a production control method suitable for low-carbon aluminum killed steel.
Background
The method comprises the steps of adopting a full deoxidation process mode in the tapping process of a converter and adjusting [ ALs ] to be 0.035-0.55%, and adopting a complicated process of blowing oxygen to remove [ ALs ] for decarburization, deoxidation, temperature regulation and carburetion alloying before RH smelting to ensure that the target component of [ C ] is qualified. The process has the problems of higher requirements on the end temperature of converter blowing, longer RH treatment time, large temperature drop in the early decarburization molten steel process, adverse cost reduction caused by removing ALs and C and carburetion, and the like, and is not only unfavorable for reducing smelting cost, but also unfavorable for high-efficiency production of steelmaking.
Chinese patent CN110484681a discloses a method for producing low-carbon low-silicon aluminum killed molten steel, wherein the molten steel is not deoxidized during tapping, and high-carbon ferromanganese is added during tapping; after tapping, adding a ladle slag modifier into the ladle slag surface to modify ladle slag; the molten steel enters RH vacuum treatment, carbonaceous materials are added in batches to carry out carbon deoxidation, after the oxygen activity is controlled to be below 50ppm, aluminum addition final deoxidation and alloy fine adjustment are carried out, so that the molten steel is discharged; and adding a ladle slag modifier into the ladle after the station to carry out modification treatment on 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 converter end-point control temperature and RH inlet temperature, and has longer RH treatment period, so that the production cost is increased and the high-efficiency production of steelmaking is not facilitated.
Disclosure of Invention
1. Problems to be solved
The invention aims to provide a steel smelting process capable of reducing energy consumption and improving efficiency;
the invention further aims to provide a smelting process capable of reducing the tapping temperature of the converter and shortening the vacuum treatment time by rhythmically controlling the feeding time and the feeding sequence.
2. Technical proposal
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,
comprising the following steps:
semi-deoxidizing molten steel in the tapping process of a converter, wherein the molten steel has an initial oxygen content not less than or equal to 400 ppm;
the tapped molten steel is treated in a vacuum degassing device;
wherein,
the semi-deoxidization comprises the following processes:
adding high-carbon manganese to regulate the manganese content and oxygen content in molten steel;
aluminum is added to regulate the oxygen content in molten steel and the oxidizing property of top slag;
adding calcium oxide to regulate the calcium-aluminum ratio of the top slag;
after the half deoxidization is finished, controlling the residual oxygen content in the molten steel to be not lower than 30% of the initial oxygen content; it is further preferable to control the remaining oxygen content in the molten steel to be not less than 40% of the initial oxygen content.
In the conventional blowing process, the low-carbon aluminum killed steel of the converter-RH-continuous casting process path has carbon content within 0.07 percent, and often adopts a complex smelting process that the converter tapping process is not deoxidized, the molten steel is subjected to oxygen-retaining RH treatment, and is subjected to complete decarburization and then deoxidization, and finally, the molten steel is subjected to carburetion alloying. The process has the problems of higher requirements on the blowing end temperature of the converter, longer RH treatment time, large temperature drop in the early decarburization molten steel process, unfavorable cost reduction in carburetion of the decarburization, and the like, and is unfavorable for not only reducing the smelting cost, but also high-efficiency production of steelmaking.
The technical proposal of the invention breaks through the semi-deoxidization treatment of molten steel in the tapping process of the converter, the deoxidization amount reaches 50 to 70 percent, and the temperature of the end point of the converter can be reduced by 5 to 15 ℃ compared with the temperature of the end point of the converter in the traditional process.
Further, in the tapping process of the molten steel from the converter, the addition of high-carbon manganese and the addition of aluminum are performed, and the residual oxygen content in the molten steel after the completion of the semi-deoxidation is controlled to be 30-50% of the initial oxygen content, and more preferably 40-55%. The general full-oxygen-removal steel has the requirements on the adding sequence of high-carbon manganese and aluminum, and the half-deoxidization in the method has no need of dividing the adding sequence of high-carbon ferromanganese and deoxidized aluminum particles, thereby being convenient for production smelting operators to operate (reducing complex process operation).
It should be noted that, if the oxygen content in the molten steel is reduced too much during the operation of this step, a large amount of aluminum is consumed, and if the oxygen content is too low, the OB rate (OB rate refers to oxygen blowing rate during RH treatment) is increased.
Further, the addition amount of the aluminum is 0.30-0.90kg/t of ton steel. The over-deoxidization treatment is preferably carried out by aluminum,
regression based on big data shows that 100ppm oxygen can be removed per 50kg of aluminium particles.
Further, selecting high-carbon ferromanganese alloy to implement the addition of the high-carbon manganese; the addition amount of the ferromanganese alloy is added according to the comprehensive consideration of the manganese content required by the target steel grade and the high-carbon manganese carburetion amount; the high-carbon ferromanganese alloy is generally selected, and the addition amount of the high-carbon ferromanganese alloy is 1.5-1.7kg/t per ton of steel. And for the high-carbon ferromanganese alloy, every 45kg/t of high-carbon ferromanganese is added into molten steel, the manganese is increased by 0.01 percent;
further, lime is selected to implement the addition of the calcium oxide, and the addition amount of the lime is 1.8-2.8kg/t of ton steel.
Further, the carbon content [ C ] of the target steel grade is determined] Target object ；
Determination of carbon content of target Steel grade [ C] Target object ；
Before molten steel enters a vacuum degassing device for treatment, temperature measurement, sampling and detection are carried out on the molten steel to obtain the carbon content [ C ] of the molten steel] Argon blowing The method comprises the steps of carrying out a first treatment on the surface of the Oxygen content [ O ]] Argon blowing The method comprises the steps of carrying out a first treatment on the surface of the (this step may be performed by means of an argon blowing station)
Confirmation [ C] Target object And [ C ]] Argon blowing The relation is satisfied to perform corresponding vacuum carbon-retaining operation;
wherein the [ C ]] Target object With [ C ]] Target lower limit value 、[C] Target value [ C ]] Target upper limit value The [ C ]] Target lower limit value <[C] Target value <[C] Target upper limit value ；
The [ C ]] Target object And [ C ]] Argon blowing The relationship satisfied between them has:<
[C] argon blowing ≤[C] Target value Or (b)
[C] Argon blowing ＞[C] Target upper limit value 。
Wherein [ C ] is as described herein] Target value To refer to the optimal value for best results.
Further, the molten steel is treated in a vacuum degassing apparatus, and the argon gas flow is 120-150Nm 3 /h; simultaneous oxygen content [ O ]] RH inbound station Oxygen determination detection of (2).
Further, when the molten steel is processed by the vacuum degassing device,
when the molten steel is processed by a vacuum degassing device,
if [ C ]] Argon blowing ≤[C] Target value Vacuumizing to 450mbar or less according to [ O ]] RH As a result, the amount of aluminum required for deoxidation (total deoxidation) was determined, and the total amount of aluminum required to be added was determined based on the amount of aluminum required for alloying.
Further, when the molten steel is treated by the vacuum degassing apparatus, the molten steel is treated by the vacuum degassing apparatus as defined in [ C] Argon blowing ＞[C] Target upper limit value Then
Firstly, decarburizing treatment is performed by oxygen in molten steel to [ C] Argon blowing ≤[C] Target upper limit value Decarburization oxygen demand is at least ([ C)] Argon blowing -[C] Target value ) 100 (formula result ensures oxygen content consumed for decarbonization);
then vacuuming to less than or equal to 450mbar, adding aluminum for deoxidization treatment, wherein the addition amount of aluminum particles is ([ O)] RH inbound station -([C] Argon blowing station -[C] Target value ) 100/2, measuring temperature and oxygen when the CO curve is less than or equal to 15%, and adding deoxidized and alloyed aluminum according to the oxygen determination result.
It should be noted here that,
1) In the case of the known oxygen content [ O ] to be removed, the calculation formula of the required aluminum amount is as follows:
① basic equation 2Al+3[ O ] for calculation]＝Al 2 O 3 ；
② At molten steel, oxygen content [ O ] in molten steel]And B ppm, the total oxygen content of the reduced molten steel is as follows:
At×1000×0.0B％＝Y(kg)；
③ calculating the addition amount Q kg of aluminum: (2×27)/(3×16) =q/Y.
2) In a vacuum state, per 100PPM of [ O ]] RH Will consume 0.01% of [ C ]]The oxygen content of the molten steel consumed for decarburization is ([ C)] Argon blowing -[C] Target value )*100；
During tapping of converters, e.g. [ C ]]Exceeding the upper limit value of the desired carbon content [ C] Target upper limit value I.e. must take the form of a formulaAnd (5) carrying out carbon retention operation under a vacuum state. Conversely, during tapping of the converter, e.g. [ C ]]Not exceeding or falling below [ C ]] Target value Then deoxidizing and supplementing carbon.
Further, after aluminum addition, the cycle time was 3min;
then, according to the component standard of the target steel grade, adding other alloys to adjust the components,
then, the air is broken after the circulation time is more than or equal to 4min, the air breaking specifically refers to the change of pressure, the pressure in the vacuum state is generally about 0.26mbar, after the circulation time is more than or equal to 4min, the air breaking valve is opened to break the air, and the pressure is restored to the normal pressure state, namely, one atmosphere pressure is 1013.25mbar.
3. Advantageous effects
Compared with the prior art, the invention has the beneficial effects that:
(1) The production control method suitable for the low-carbon aluminum killed steel provided by the invention is characterized in that manganese and aluminum are added in the tapping process of the converter to carry out a composite semi-deoxidization process, so that the OB ratio of vacuum smelting can be effectively reduced.
(2) The production control method suitable for the low-carbon aluminum killed steel provided by the invention is characterized in that the carbon is reserved in the RH vacuum state, and whether RH needs decarburization is determined according to the analysis result of the carbon content of the sample in the argon blowing station. If not decarburizing, directly adding aluminum for deoxidization and then alloying; if decarburization is needed, incomplete decarburization is carried out, RH first-step pre-deoxidation content is calculated according to an allowable amount range and an optimal target value of carbon content and the carbon content of an argon blowing station, partial oxygen is reserved for decarburization to a target value of carbon content of steel grade, and carburetion is not needed during alloying. The RH smelting period is greatly shortened, the requirements of the end temperature and the RH arrival temperature of the converter are reduced, the production cost is greatly reduced, and the production efficiency is improved;
compared with the traditional smelting process of completely decarbonizing and deoxidizing after oxygen-retaining RH treatment of molten steel in the tapping process of a converter, the smelting process of final temperature drop of the converter is reduced by 5-15 ℃, RH treatment time is reduced by 13min on average, 7min on average, production efficiency is greatly improved, smelting time is shortened, and production cost is greatly reduced due to temperature reduction.
Detailed Description
The present invention is further illustrated below with reference to specific examples, which are not intended to limit the invention in any way. Unless specifically stated otherwise, the reagents, methods and apparatus employed in the present invention are those conventional in the art;
the essential features and significant effects of the invention can be seen from the following examples, which are described as some, but not all, of which, therefore, are not limiting of the invention, and some of the insubstantial modifications and adaptations of the invention by those skilled in the art are within the scope of the 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; the term and/or any and all combinations including one or more of the associated listed items.
As used herein, a range of "no less than" a value or "no greater than" a value is understood to include the value, such as "no less than 100ppm of a substance," it is understood that "the amount of the substance may be 100ppm, or greater than 100 ppm.
The high-efficiency smelting process of the low-carbon aluminum killed steel is provided, and the method relates to a process route for smelting steel types, which comprises the following steps: 300tBOF (300 ton converter) → CT (argon blowing station) → RH (RH vacuum refining furnace) → CC (continuous casting machine), comprising the steps of:
(1) The later stage of converter blowing adopts a strong bottom blowing mode, the stirring of a molten pool is enhanced, and the terminal carbon and terminal oxygen content [ O ] of the converter is reduced; the terminal temperature of the transfer furnace is 1630-1645 ℃;
(2) Manganese (preferably high-carbon ferromanganese), aluminum (preferably deoxidized aluminum particles) and lime are sequentially added in the tapping process of the converter, wherein the lime addition amount is 1.8-2.8kg/t of ton steel; the high-carbon ferromanganese is added according to the control lower limit of the manganese content of the actual smelting steel, the manganese is added by 0.01% when the high-carbon ferromanganese is added every 45kg/t, and the addition amount of aluminum particles is 0.30-0.90kg/t for each ton of steel; for example, according to a 300 ton converter, as shown in table 1 below, an exemplary reference amount of aluminum metal added according to the converter tapping endpoint oxygen content O corresponds to the table below (the amount of aluminum added in the table below may 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 |
| aluminium addition/Kg | 100 | 130 | 150 | 180 | 220 | 280 |
(3) After the argon blowing station performs temperature measurement and sampling, the ladle is capped and transferred to RH for refining;
(4) RH inbound temperature measurement sampling adopts a deep treatment mode in the whole process, the gas flow is lifted to 120-150Nm3/h, and the carbon reserving operation is as follows: (1) if [ C ]] Argon blowing station ≤[C] Target upper limit value Without decarbonization, when RH starts to treat and vacuumize toWhen the oxygen concentration is less than or equal to 450mbar, directly adding the aluminum required by deoxidation and alloying according to the oxygen concentration result, adding other alloys to adjust to a target value after the aluminum particles are added and the circulation time is 3min, and breaking the blank after the circulation time is more than or equal to 4min; (2) if [ C ]]Argon blowing station > [ C ]] Target upper limit value Vacuum reserved oxygen decarburization is needed, and the reserved decarburization oxygen amount is (C)]Argon blowing station- [ C]Target value) 100. When RH starts to be treated and vacuumized to be less than or equal to 450mbar, adding pre-deoxidized aluminum particles, and returning 50kg of aluminum particles to remove 100ppm of oxygen content according to big data, wherein the addition amount of the aluminum particles is ([ O) ]RH inbound station -([C] Argon blowing station -[C] Target value ) 100/2, measuring temperature and oxygen when the CO curve is less than or equal to 15%, adding deoxidized and alloyed aluminum according to the oxygen determination result, adding the rest alloy to adjust to a target value after the aluminum particle is added for 3min, and breaking the blank after the alloying for more than or equal to 4min.
The RH inbound temperature is 1594 ℃; RH outbound temperature is 1586 ℃;
the invention is further described below in connection with specific embodiments.
Example 1
The process flow of smelting the steel grade DC01 comprises 300 tBOF- & gt CT- & gt RH- & gtCC, and comprises the following steps:
(1) The later stage of converter blowing adopts a strong bottom blowing mode, the stirring of a molten pool is enhanced, the terminal temperature of the converter is 1646 ℃, the terminal oxygen is 430ppm, and the terminal carbon is 0.028%;
(2) High-carbon ferromanganese, deoxidized aluminum particles and lime are added in sequence in the tapping process of the converter;
specifically, when the steel water amount of the converter tapping reaches 30+/-5% of the total amount of molten steel, firstly adding high-carbon ferromanganese into the molten steel; when the molten steel amount tapped from the converter reaches 75+/-5% of the total molten steel amount, adding deoxidized aluminum particles into the molten steel; finally adding lime;
wherein the lime addition amount is 2.63kg/t of ton steel, the high-carbon ferromanganese addition amount is 1.17kg/t of ton steel, and the aluminum particle addition amount is 0.42kg/t of ton steel;
(3) Argon blowing station temperature measurement 1620 ℃, oxygen content 229ppm and carbon content 0.024;
(4) RH in-station temperature measurement and sampling, adopting a deep treatment mode in the whole process, lifting the gas flow by 140Nm3/h, judging that decarburization is not needed according to the target of the DC01 carbon content of 0.020%, adopting the scheme of the operation (1), measuring the RH in-station temperature by 1597 ℃, determining the oxygen by 220ppm, calculating 0.93kg/t of added aluminum, adding medium carbon ferromanganese for 4min after the aluminum addition, adjusting Mn to the target value, and performing alloying for 5min after the alloying for breaking; the RH end point carbon content is 0.0210%, the rest components are qualified, and the RH outlet temperature is 1586 ℃; RH treatment time was 12min.
Example 2
The process flow of smelting the steel DX51D comprises 300 tBOF- & gt CT- & gt RH- & gt CC, and comprises the following steps of:
(1) The later stage of converter blowing adopts a strong bottom blowing mode, the stirring of a molten pool is enhanced, the terminal temperature of the converter is 1640 ℃, the terminal oxygen is 412ppm, and the terminal carbon is 0.046%;
(2) High-carbon ferromanganese, deoxidized aluminum particles and lime are added in sequence in the tapping process of the converter;
specifically, when the steel water amount of the converter tapping reaches 30+/-5% of the total amount of molten steel, firstly adding high-carbon ferromanganese into the molten steel; when the molten steel amount tapped from the converter reaches 75+/-5% of the total molten steel amount, adding deoxidized aluminum particles into the molten steel; finally adding lime;
wherein the lime addition amount is 2.51kg/t of ton steel, the high carbon ferromanganese addition amount is 1.17kg/t of ton steel, and the aluminum particle addition amount is 0.41kg/t of ton steel;
(3) Argon blowing station temperature measurement 1609 ℃, oxygen content 300ppm and carbon content 0.037%;
(4) The RH is measured and sampled at the station, the deep treatment mode is adopted in the whole process, the gas flow is lifted to 130Nm3/h, the decarburization is judged according to the DX51D carbon content target of 0.025%, the operating scheme (2) is adopted, the RH is measured at the station and is 1596 ℃, the oxygen is determined to 313ppm, the pre-deoxidized aluminum is calculated to be 0.32kg/t, the aluminum is added and circulated for 3min, the oxygen is determined to 117ppm when the CO curve is 13.4%, the deoxidized and alloyed is added to be 0.83kg/t, the medium-carbon ferromanganese is regulated to the target value after the circulation for 3min, the alloying is circulated for 4min to break the air, the RH end point carbon content is 0.0255%, the rest components are qualified, the RH outlet temperature is 1584 ℃, and the RH treatment time is 14min.
Comparative example 1
Smelting steel SPHC with target carbon of 0.05%, and the process flow of 300 tBOF- & gt CT- & gt RH- & gtCC comprises the following steps:
(1) The later stage of converter blowing adopts a strong bottom blowing mode, the stirring of a molten pool is enhanced, the final temperature of the converter is 1667 ℃, the final oxygen content is 447ppm, and the final carbon content is 0.032;
(2) Lime is added in the tapping process of the converter, wherein the lime addition amount is 3.1kg/t of ton steel; at the stage, neither carbon ferromanganese nor aluminum particles are added;
(3) The argon blowing station measures 1634 ℃, the oxygen content is 497ppm, and the carbon content is 0.024%;
(4) RH is subjected to station-entering temperature measurement and sampling, a shallow treatment mode is adopted in the whole process, the gas flow is lifted to 140Nm3/h, the RH is subjected to station-entering temperature measurement to 1616 ℃, oxygen is determined to 481ppm, RH is decarburized for 9min, the carbon content is 50-100ppm after decarburization, deoxidized and alloyed aluminum is added according to the oxygen determination result after decarburization, the alloyed carbon powder and medium-carbon ferromanganese are respectively added after the aluminum particles are added for 4min for circulation, the speed is 0.32kg/t, the speed is 2.38kg/t, the speed of steel scraps is 3.8kg/t, and the circulation time is 5min for empty breaking after alloying; the RH end point carbon content is 0.0496%, the rest components are qualified, and the RH outlet temperature is 1586 ℃; RH treatment time was 20min.
Claims (5)
1. A production control method suitable for low-carbon aluminum killed steel is characterized in that,
comprising the following steps:
semi-deoxidizing molten steel in the tapping process of a converter, wherein the molten steel has an initial oxygen content of more than or equal to 400 ppm; wherein the semi-deoxidizing comprises the following processes:
in the tapping process of molten steel from a converter, adding high-carbon manganese and aluminum, and controlling the residual oxygen content in the molten steel after the semi-deoxidation is completed to be 40-55% of the initial oxygen content
The addition of high-carbon manganese is used for adjusting the manganese content and the oxygen content in molten steel;
aluminum is added to regulate the oxygen content in molten steel and the oxidizing property of top slag;
adding calcium oxide to adjust the calcium-aluminum ratio of the top slag;
determination of carbon content of target Steel grade [ C] Target object The method comprises the steps of carrying out a first treatment on the surface of the Before molten steel enters a vacuum degassing device for treatment, temperature measurement, sampling and detection are carried out on the molten steel to obtain the carbon content [ C ] of the molten steel] Argon blowing The method comprises the steps of carrying out a first treatment on the surface of the Oxygen content [ O ]] Argon blowing ；
Confirmation [ C] Target object And [ C ]] Argon blowing The relation is satisfied to perform corresponding vacuum carbon-retaining operation;
wherein the [ C ]] Target object With [ C ]] Target lower limit value 、[C] Target value [ C ]] Target upper limit value The [ C ]] Target lower limit value <[C] Target value < [C] Target upper limit value ；
The [ C ]] Target object And [ C ]] Argon blowing The relationship satisfied between them has:
[C] argon blowing ≤[C] Target value Or (b)
[C] Argon blowing ＞[C] Target upper limit value;
when the tapped molten steel is treated in a vacuum degassing device, the argon gas flow is 120-150Nm < 3 >/h; oxygen content [ O ]] RH Oxygen determination detection of (2);
if [ C ]] Argon blowing ≤[C] Target value Vacuumizing to 450mbar or less according to [ O ]] RH As a result, determining the amount of aluminum required for deoxidation, and determining the total amount of aluminum required to be added according to the amount of aluminum required for alloying;
if [ C ]] Argon blowing ＞[C] Target upper limit value Then
Firstly, decarburizing treatment is performed by oxygen in molten steel to [ C] Argon blowing ≤[C] Target upper limit value The oxygen content of the decarburized molten steel was ([ C)] Argon blowing -[C] Target value ）×100；
Then vacuuming to less than or equal to 450mbar, adding aluminum for deoxidization treatment, wherein the addition amount of aluminum particles is ([ O)] RH inbound station -（[C] Argon blowing station -[C] Target value ) And (x 100)/2, measuring temperature and oxygen when the CO curve is less than or equal to 15%, and adding deoxidized and alloyed aluminum according to the oxygen determination result.
2. The production control method for low-carbon aluminum killed steel according to claim 1, wherein the addition amount of aluminum is 0.30-0.90kg/t per ton of steel calculated according to the oxygen content of the molten steel at the end point of the converter.
3. The production control method for low-carbon aluminum killed steel according to claim 2, wherein,
selecting high-carbon ferromanganese alloy to implement the addition of the high-carbon manganese; the addition amount of the high-carbon ferromanganese alloy is 1.5-1.7kg/t of ton steel.
4. The production control method for low-carbon aluminum killed steel according to claim 3, wherein,
lime is selected to implement the addition of the calcium oxide, and the addition amount of the lime is 1.8-2.5kg/t of ton steel.
5. The production control method for low-carbon aluminum killed steel according to any one of claims 1 to 4, wherein,
after aluminum addition, the cycle time was 3min;
then, according to the component standard of the target steel grade, adding other alloys to adjust the components;
then, the circulation time is more than or equal to 4min;
and finally, the negative pressure breaks the air to the normal pressure state.
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| CN103642970A (en) * | 2013-12-09 | 2014-03-19 | 攀钢集团攀枝花钢铁研究院有限公司 | Smelting method of low-carbon aluminum killed steel |
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| CN101240397A (en) * | 2008-02-29 | 2008-08-13 | 南京钢铁股份有限公司 | Converter-RH-LF-continuous casting technique for producing pipe line steel |
| CN103642970A (en) * | 2013-12-09 | 2014-03-19 | 攀钢集团攀枝花钢铁研究院有限公司 | Smelting method of low-carbon aluminum killed steel |
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