CN106011384A - Method for smelting non-sedating molten steel - Google Patents
Method for smelting non-sedating molten steel Download PDFInfo
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- CN106011384A CN106011384A CN201610450518.4A CN201610450518A CN106011384A CN 106011384 A CN106011384 A CN 106011384A CN 201610450518 A CN201610450518 A CN 201610450518A CN 106011384 A CN106011384 A CN 106011384A
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- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 138
- 239000010959 steel Substances 0.000 title claims abstract description 138
- 238000000034 method Methods 0.000 title claims abstract description 71
- 238000003723 Smelting Methods 0.000 title claims abstract description 24
- 230000001624 sedative effect Effects 0.000 title claims abstract description 9
- 239000001301 oxygen Substances 0.000 claims abstract description 93
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 93
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 90
- 238000005261 decarburization Methods 0.000 claims abstract description 55
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 50
- 230000008569 process Effects 0.000 claims abstract description 41
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 33
- 238000006243 chemical reaction Methods 0.000 claims abstract description 31
- 238000010079 rubber tapping Methods 0.000 claims abstract description 28
- 238000005275 alloying Methods 0.000 claims abstract description 7
- 239000003795 chemical substances by application Substances 0.000 claims abstract description 6
- 229910000655 Killed steel Inorganic materials 0.000 claims abstract description 4
- 230000000694 effects Effects 0.000 claims description 42
- 239000002893 slag Substances 0.000 claims description 24
- 230000004048 modification Effects 0.000 claims description 17
- 238000012986 modification Methods 0.000 claims description 17
- 239000007789 gas Substances 0.000 claims description 8
- 238000009529 body temperature measurement Methods 0.000 claims description 7
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 6
- 229910052782 aluminium Inorganic materials 0.000 claims description 6
- 230000008859 change Effects 0.000 claims description 6
- 239000002245 particle Substances 0.000 claims description 3
- 229910001021 Ferroalloy Inorganic materials 0.000 claims description 2
- 238000007664 blowing Methods 0.000 abstract description 12
- 238000007670 refining Methods 0.000 description 10
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 8
- 239000003607 modifier Substances 0.000 description 8
- 230000036284 oxygen consumption Effects 0.000 description 7
- 238000010438 heat treatment Methods 0.000 description 6
- 238000004519 manufacturing process Methods 0.000 description 6
- CSJDCSCTVDEHRN-UHFFFAOYSA-N methane;molecular oxygen Chemical compound C.O=O CSJDCSCTVDEHRN-UHFFFAOYSA-N 0.000 description 6
- 229910001295 No alloy Inorganic materials 0.000 description 4
- 229910052786 argon Inorganic materials 0.000 description 4
- 238000005266 casting Methods 0.000 description 4
- 238000005262 decarbonization Methods 0.000 description 4
- 230000001174 ascending effect Effects 0.000 description 3
- 238000002360 preparation method Methods 0.000 description 3
- 230000035484 reaction time Effects 0.000 description 3
- 230000033764 rhythmic process Effects 0.000 description 3
- 206010039897 Sedation Diseases 0.000 description 2
- 238000007872 degassing Methods 0.000 description 2
- 238000006213 oxygenation reaction Methods 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- 230000036280 sedation Effects 0.000 description 2
- 238000009628 steelmaking Methods 0.000 description 2
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 1
- 229910000640 Fe alloy Inorganic materials 0.000 description 1
- 229910000616 Ferromanganese Inorganic materials 0.000 description 1
- 229910000519 Ferrosilicon Inorganic materials 0.000 description 1
- 241001062472 Stokellia anisodon Species 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 230000004075 alteration Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000009835 boiling Methods 0.000 description 1
- 230000001914 calming effect Effects 0.000 description 1
- 229910002091 carbon monoxide Inorganic materials 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 150000002431 hydrogen Chemical class 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 230000010354 integration Effects 0.000 description 1
- DALUDRGQOYMVLD-UHFFFAOYSA-N iron manganese Chemical compound [Mn].[Fe] DALUDRGQOYMVLD-UHFFFAOYSA-N 0.000 description 1
- 230000003068 static effect Effects 0.000 description 1
- 239000002436 steel type Substances 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 238000009489 vacuum treatment Methods 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 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
- C21C7/10—Handling in a vacuum
-
- 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
- C21C7/0025—Adding carbon material
-
- 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
- C21C7/04—Removing impurities by adding a treating agent
- C21C7/068—Decarburising
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- 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 provides a method for smelting non-sedating molten steel, which is characterized by comprising the following steps: the method comprises the following steps: tapping the non-killed steel of the converter; the non-sedating molten steel enters an LF furnace to be heated; the heated molten steel enters an RH procedure to carry out decarburization reaction; oxygen is determined, and a deoxidizing agent is added to finish the decarburization reaction; and (4) deoxidizing and alloying. The invention adopts a mode of combining the LF furnace physical temperature rise and the RH carbon deoxidation mode to solve the contradiction between the control of the low oxygen level and the temperature, and eliminates the operation of oxygen blowing or reserved high oxygen level temperature rise caused by insufficient temperature in the RH treatment process, thereby being capable of controlling the low oxygen level before deoxidation more stably in the RH process, fundamentally reducing the generation of deoxidation products and improving the purity of molten steel.
Description
Technical Field
The invention relates to the technical field of refining processes in the metallurgical industry, in particular to a method for smelting non-sedating molten steel.
Background
The RH (molten steel vacuum circulation degassing) system equipment is a molten steel secondary refining process equipment for producing high-quality steel, and before molten steel treatment, a dip pipe is firstly immersed into molten steel of a steel ladle to be treated. When the vacuum vessel is evacuated, the atmospheric pressure on the surface of the molten steel forces the molten steel to flow from the dip tube into the vacuum vessel (about 0.67mbar in the vacuum vessel causes the molten steel to rise to a height of 1.48 m). And two dip pipes communicated with the vacuum tank, one is an ascending pipe, and the other is a descending pipe. Because the ascending pipe continuously blows argon gas into the molten steel, a higher static pressure difference is generated relative to the descending pipe without blowing argon gas, so that the molten steel enters from the ascending pipe and flows to the descending pipe through the lower part of the vacuum tank, and the process is continuously circulated and repeated. In a vacuum state, argon, hydrogen, carbon monoxide and other gases flowing through the vacuum channel steel water are pumped away in the molten steel circulation process. Meanwhile, the molten steel entering the vacuum tank also carries out a series of metallurgical reactions, such as vacuum decarburization, which mainly depends on oxygen in the molten steel to carry out decarburization in a vacuum chamber, and the like; the molten steel is purified by such circular degassing and refining.
At present, the molten steel is smelted in a mode of tapping by a converter, the molten steel is boiling steel when in refining and station entering and contains higher oxygen activity, decarburization reaction is firstly carried out in the RH treatment process, then a deoxidizing agent is added for carrying out the calming treatment of the molten steel, so that more deoxidizing agent is consumed, a large amount of deoxidizing products are generated, most of the deoxidizing products exist in the molten steel in the form of inclusions, and the purity of the molten steel and the quality of subsequent products are greatly influenced; in order to control the deoxidation products with lower content, the tapping oxygen activity of the converter is reduced by source control, the tapping oxygen activity control of the converter and the temperature control are in a certain proportional relation, and the reduction of the tapping oxygen activity of the converter leads to the reduction of the tapping temperature, so that the oxygen blowing heating operation is carried out in the refining process, and a large amount of deoxidation products are generated; the tapping temperature of the converter is increased, the refining enters a station to obtain higher oxygen activity and temperature, the refining process is carried out carbon deoxidation operation to obtain lower oxygen activity before deoxidation, but the improvement of the temperature of the molten steel has great influence on the condition of the converter and the cost, so that the existing smelting molten steel has certain contradiction to the control of lower deoxidation products.
The carbon element is used as the optimal deoxidizing element, deoxidizing products cannot pollute molten steel, how to utilize the carbon element to complete deoxidizing work to the maximum extent is the key point of how to balance the relation between the oxygen activity and the temperature of the molten steel, and the relation between the oxygen activity and the temperature of the molten steel is difficult to balance by the conventional treatment mode in mass production.
Disclosure of Invention
Aiming at the problems in the prior art, the invention provides a method for smelting non-sedated molten steel, which is characterized in that a ladle refining furnace (LF) is combined with an RH process to smelt the molten steel, and the contradiction between the low oxygen level and the temperature is solved and controlled by combining the physical temperature rise of the LF and the carbon deoxidation mode of the RH, so that lower molten steel oxygen activity and oxygen blowing proportion can be stably obtained during molten steel smelting, and further, high-purity molten steel can be obtained.
In order to achieve the purpose, the invention adopts the following technical scheme: a method for smelting non-sedating molten steel,
tapping the non-killed steel of the converter;
the non-sedated molten steel enters an LF furnace to be heated;
the heated non-sedated molten steel enters an RH procedure to carry out decarburization reaction;
oxygen is determined, and a deoxidizing agent is added to finish the decarburization reaction;
and (4) deoxidizing and alloying.
More preferably, the temperature is raised to a temperature satisfying the treatment requirement in the RH step in the LF furnace.
More preferably, after the temperature rise in the LF furnace is completed, the non-sedated molten steel is subjected to a slag upgrading operation in the LF furnace.
As a further preference, the slag upgrading operation comprises the following steps: the slag modification operation is carried out by using aluminum particles or aluminum slag.
Further preferably, the temperature measurement and oxygen determination operation is performed when the non-sedated molten steel enters the RH step.
More preferably, after the temperature measurement and oxygen determination operation, if the carbon content of the molten steel is high or low, the molten steel is vacuumized to perform decarburization reaction; if the molten steel has high oxygen and low carbon, carbon powder is pre-added for pre-deoxidation and then decarburization reaction is carried out.
Preferably, the RH process further comprises an oxygen blowing step, wherein whether oxygen blowing operation is performed is judged according to the carbon-oxygen ratio, the oxygen consumption for decarburization is 1:1.33, and the level of 200-300ppm of oxygen activity is reserved in consideration of oxygenation in the vacuum chamber.
As a further preferred, the pre-carbon powder step is as follows: and jacking the steel ladle until the dip pipe is inserted into the molten steel surface, and adding the carbon powder into a vacuum tank for vacuum operation.
More preferably, it is determined whether the decarburization reaction in the RH step is in a gradual trend based on the decarburization time or the CO value in the gas analyzer, and the oxygen determination operation is performed when the decarburization reaction is in a gradual trend.
Further preferably, the amount of carbon consumed in the decarburization reaction is calculated from the change in oxygen level, and then carbon powder and an iron alloy are added according to the target values.
Preferably, the deoxidized and alloyed molten steel is subjected to pure cycle time and temperature control required by steel grades, then is broken and poured on a ladle casting machine.
More preferably, the temperature of the molten steel during tapping of the converter is 1620 ℃ to 1650 ℃, the temperature of the molten steel entering the RH process is 1610 ℃ to 1630 ℃, and the oxygen activity is 300ppm to 600 ppm.
Further preferably, the temperature of the molten steel entering the LF furnace is 1550-.
Further preferably, the oxygen activity at the end of decarburization is 180-280 ppm.
The invention has the following beneficial effects:
1. the invention adopts steel-making low-temperature low-oxygen-level non-sedated tapping, hangs molten steel to an LF furnace for heating treatment after tapping is finished, ensures that the temperature of the LF furnace after heating meets the RH treatment requirement, then hangs the molten steel to an RH process for light treatment deoxidation operation, finishes the earlier stage deoxidation work of the molten steel by utilizing carbon in the molten steel, controls the oxygen activity in the molten steel to a low point (IF steel can be controlled between 250 and 300 ppm), and finishes the calculation of decarburization amount according to the oxygen consumption in the process, thereby finishing the smelting work of the furnace on the basis of not increasing the RH treatment time, and thus stably obtaining the molten steel with low deoxidation products on the basis of ensuring large production.
2. In the process of light treatment in the RH furnace, the light treatment molten steel is smelted in a mode of calculating the decarbonization amount according to the oxygen consumption in the process, which is completely different from the current mode of determining the carbon content range by controlling the oxygen activity range.
3. The invention solves the contradiction between the low oxygen level control and the temperature by combining the LF furnace physical temperature rise and the RH carbon deoxidation mode, eliminates the operation of oxygen blowing or reserved high oxygen level temperature rise caused by insufficient temperature in the RH treatment process, thereby being capable of controlling the low oxygen level before deoxidation in the RH process more stably, reducing the generation of deoxidation products fundamentally and improving the purity of molten steel.
Drawings
FIG. 1 is a schematic flow chart of a method for smelting non-sedated molten steel according to an embodiment of the present application.
Detailed Description
The application provides a method for smelting non-sedating molten steel, the contradiction between the low oxygen level control and the temperature is solved by combining the LF furnace physical temperature rise and the RH carbon deoxidation mode, the operation of oxygen blowing or reserved high oxygen level temperature rise caused by insufficient temperature in the RH treatment process is eliminated, so that the low oxygen level before deoxidation can be stably controlled in the RH process, the generation of deoxidation products is fundamentally reduced, and the purity of the molten steel is improved.
For better understanding of the technical solutions of the present application, the technical solutions will be described in detail below with reference to the drawings and specific embodiments of the present application.
As shown in FIG. 1, the method for smelting non-sedating molten steel according to the embodiment of the application comprises the following steps:
A. tapping the non-killed steel of the converter;
B. the non-sedated molten steel enters an LF furnace to be heated;
C. after the temperature rise is finished, the molten steel enters an RH procedure for decarburization reaction to consume the oxygen activity in the molten steel, so that the oxygen activity before deoxidation is controlled to be a lower value;
D. oxygen is determined, and a deoxidizing agent is added to finish the decarburization reaction;
E. and (4) deoxidizing and alloying.
In the step A, the molten steel which is not subjected to the sedation tapping of the converter is tapped at a low temperature and a low oxygen level without considering the following temperature insufficiency and the post-blowing operation caused by the low temperature. The non-sedated molten steel is molten steel which is not subjected to deoxidation treatment or is incompletely deoxidized in the converter tapping process, and the molten steel in a ladle contains certain oxygen activity after the converter tapping is finished.
In the step B, the condition of finishing the temperature rise control is to ensure that the temperature meets the treatment requirement of the RH procedure, so that the RH does not need to be raised in temperature.
In the step B, the non-sedated molten steel can be subjected to appropriate slag modification operation in an LF furnace to ensure that the oxidability of the slag meets the RH steel grade requirement, wherein the slag modification operation is performed after the temperature rise control is finished. The slag modification operation steps are as follows: the slag modification operation is carried out by using aluminum particles or aluminum slag, argon is controlled not to be turned over greatly during modification, slight surging of the slag surface is ensured, and violent stirring of molten steel and the slag surface is avoided.
And step C, when the RH molten steel enters the station, firstly carrying out temperature measurement and oxygen determination operation, and calculating whether the oxygen activity of the molten steel can be controlled within a target range according to the entering oxygen activity and the carbon content after the furnace.
If the carbon content is high and the oxygen content is low, directly vacuumizing to perform decarburization reaction;
if the oxygen content is high and the carbon content is low, the oxygen activity in the molten steel cannot be controlled within a target value, and carbon powder is pre-added for pre-deoxidation and then decarburization reaction is carried out.
The pre-carbon powder adding step is as follows: jacking the steel ladle until the dip pipe is inserted into the molten steel surface, and then adding the calculated carbon powder into a vacuum tank for vacuum operation; adding carbon powder before vacuum; the calculation of the added carbon powder amount is related to the oxygen activity increase value, a calculation formula can be designed, the added carbon powder amount is calculated according to a target value, and then the minimum adding range is set to judge whether the added carbon powder is added.
And step C, an oxygen blowing step is further included, whether oxygen blowing operation is performed or not is judged according to the carbon-oxygen ratio, the decarburization oxygen consumption is 1:1.33, and the oxygen level is reserved at the level of 200-300ppm considering the oxygenation of the vacuum chamber.
And C, judging whether the decarburization reaction in the step C is in a gentle trend according to the decarburization time or the CO value in the gas analyzer, namely ensuring that the change trend of the oxygen activity in the molten steel is in a calm trend, and carrying out oxygen determination operation if the decarburization reaction is in a gentle trend.
In step E, the carbon consumption of the decarburization (carbon-oxygen) reaction is calculated according to the change of the oxygen level, and then carbon powder and ferroalloy, such as ferrosilicon or ferromanganese, are added according to the target value.
And E, after the pure cycle time and temperature control required by steel grade are finished, the molten steel treated in the step E is broken, and the steel is poured on a ladle casting machine.
In the embodiment of the application, the temperature of the non-sedated molten steel during tapping of the converter is 1620-1650 ℃, the temperature of the non-sedated molten steel entering the LF furnace is 1580 ℃ in 1550-; the decarburization reaction time is 5-30min, and the oxygen activity at the end of decarburization is 180-280 ppm.
Example 1:
according to the novel method for smelting molten steel, provided by the embodiment 1 of the application, the low oxygen activity before deoxidation is stably and effectively controlled through integration of different refining processes, a refined LF furnace and RH process route is considered in rhythm arrangement of a scheduling room, and production preparation work is made for overall rhythm matching and subsequent production preparation arrangement; the method specifically comprises the following steps:
step S1: when a refining period is set by the dispatching room, a reasonable on-site period and subsequent production preparation work are set according to a subsequent LF furnace and RH process route;
step S2: the low-temperature low-oxygen position non-sedated steel is tapped in the converter, the tapping temperature of the converter is 1620 ℃ to 1650 ℃ according to the requirements of different steel types, the carbon content of the molten steel is controlled to be more than 3 percent, and the molten steel is not deoxidized and alloyed when being put into a ladle; hoisting the molten steel to an LF furnace for heating;
step S3: after molten steel in an LF furnace process arrives at a station, carrying out temperature measurement operation, predicting the temperature of the arriving station to be about 1550-; after the temperature rise is finished, arranging the molten steel to be hung to RH for treatment according to the rhythm;
step S4: RH enters a station to carry out temperature measurement and oxygen determination operation, the entering temperature is about 1610-;
step S5: carrying out RH decarburization treatment: RH adopts the way of pre-adjusting carbon powder or direct vacuum treatment to carry out decarburization and oxygen consumption reaction according to the station-entering condition, and judges whether the decarburization reaction is in a gentle trend or not according to the carbon-oxygen reaction time or the CO value in a gas analyzer; wherein,
if the oxygen is high and the carbon is low when the steel enters the station, pre-adding carbon powder to deoxidize, jacking the steel ladle until the dip pipe is inserted into the molten steel surface, and then adding the calculated carbon powder into a vacuum tank to carry out vacuum starting operation;
judging whether the decarburization reaction is in a gentle trend or not according to the decarburization reaction time or a CO value in a gas analyzer, and searching data according to self equipment, so that the stability of a decarburization reaction area is stably and accurately mastered, and the oxygen activity in molten steel does not change obviously any more;
and combining actual data with theoretical calculation to obtain the application of the corresponding relation in the carbon-oxygen reaction in the region.
Controlling the decarburization time of the LCAK steel grade light treatment to be 6-8min, and implementing the decarburization time of the IF steel grade according to the end C content requirement: when the steel grade with the target carbon content lower than 15ppm is produced, the decarburization time is controlled within 20min-25 min; when the steel grade with the target carbon content of 15ppm-60ppm is produced, the decarburization time is controlled within 15min-20 min.
Step S6: after the decarburization task is finished, controlling the oxygen activity within a target range, then carrying out deoxidation alloying operation according to a constant oxygen value, calculating the carbon consumption of carbon-oxygen reaction according to the change of an oxygen level, then adding carbon powder and other alloys according to a target value, and finishing the deoxidation alloying of the furnace;
step S7: after the pure cycle time and temperature control required by steel grade are finished, the air is broken, and the crane ladle is put on a casting machine for casting.
Parameters example 1.1:
the LCAK steel grade has the converter tapping temperature of 1630 ℃, no alloy or modifier is added in the tapping process, and the furnace post-temperature is 1580 ℃. The station entry temperature of the LF furnace is 1563 ℃, the oxygen activity is 553ppm, 1.3t of ternary synthetic slag is added in the treatment process of the LF furnace for submerged arc, the temperature is raised for 18min, the temperature is finished at 1630 ℃, and 600Kg of modifier is added for modifying slag. Carrying out decarburization treatment on a crane ladle RH, wherein the station entering temperature is 1615 ℃, the oxygen activity is 610ppm, the station entering temperature is C: 0.041 percent, adding 30Kg of carbon powder for pre-deoxidation, and naturally decarbonizing for 7min, wherein the oxygen activity is 217ppm after the decarbonization is finished.
Parameters example 1.2:
the IF steel has the upper limit carbon of 30ppm, the converter tapping temperature of 1641 ℃, no alloy or modifier added in the tapping process, and the furnace post-temperature of 1593 ℃. The station entering temperature of the LF furnace is 1573 ℃, the oxygen activity is 542ppm, 1.0t of ternary synthetic slag is added in the treatment process of the LF furnace for submerged arc, the temperature is raised for 19min, the temperature is finished at 1632 ℃, and 500Kg of modifier is added for slag modification operation. Carrying out RH decarburization treatment on the crane ladle, wherein the station entering temperature is 1618 ℃, the oxygen activity is 589ppm, the station entering temperature is C: 0.037 percent, natural decarburization for 15min, and the oxygen activity at the end of decarburization is 262 ppm.
Parameters example 1.3:
the IF steel has the upper limit carbon of 10ppm, the converter tapping temperature of 1645 ℃, no alloy or modifier added in the tapping process, and the furnace post-temperature of 1591 ℃. The station entry temperature of the LF furnace is 1569 ℃, the oxygen activity is 521ppm, 1.0t of ternary synthetic slag is added in the treatment process of the LF furnace for submerged arc, the temperature is raised for 20min, the temperature is finished at 1636 ℃, and 500Kg of modifier is added for slag modification operation. Carrying out RH decarburization treatment on the crane ladle, wherein the station entering temperature is 1620 ℃, the oxygen activity is 577ppm, and the station entering temperature is C: 0.039%, naturally decarbonizing for 20min, and finishing decarbonization to obtain 259ppm of oxygen activity.
Parameters example 1.4:
LCAK steel grade, the converter tapping temperature is 1625 ℃, no alloy and modifier are added in the tapping process, and the furnace post-temperature is 1581 ℃. The station entry temperature of the LF furnace is 1565 ℃, the oxygen activity is 483ppm, 1.0t of ternary synthetic slag is added in the treatment process of the LF furnace for submerged arc, the temperature is raised for 17min, the temperature is finished at 1631 ℃, and 450Kg of modifier is added for slag modification operation. Carrying out decarburization treatment on a crane ladle RH, wherein the station entering temperature is 1617 ℃, the oxygen activity is 532ppm, the station entering temperature is C: 0.049 percent, natural decarburization for 7min, and the oxygen activity after decarburization is 115 ppm.
The technical scheme in the embodiment of the application at least has the following technical effects or advantages:
1. according to the invention, molten steel in a non-sedation treatment mode is tapped at a low-temperature and low-oxygen position during steelmaking, the molten steel is hoisted to an LF furnace for heating treatment after tapping is finished, the temperature of the LF furnace after heating is ensured to meet the RH treatment requirement, then the molten steel is hoisted to an RH process for light treatment and deoxidation operation, the earlier-stage deoxidation work of the molten steel is completed by utilizing carbon in the molten steel, the oxygen activity in the molten steel is controlled to be low (IF steel can be controlled to be between 250 and 300 ppm), and the decarburization amount is calculated according to the oxygen consumption in the process, so that the smelting work of the furnace is completed on the basis of not increasing the RH treatment time, and thus the molten steel with low deoxidation products is stably obtained on the basis of ensuring large production.
2. In the process of light treatment in the RH furnace, the light treatment molten steel is smelted in a mode of calculating the decarbonization amount according to the oxygen consumption in the process, which is completely different from the current mode of determining the carbon content range by controlling the oxygen activity range.
3. The invention solves the contradiction between the low oxygen level control and the temperature by combining the LF furnace physical temperature rise and the RH carbon deoxidation mode, eliminates the operation of oxygen blowing or reserved high oxygen level temperature rise caused by insufficient temperature in the RH treatment process, thereby being capable of controlling the low oxygen level before deoxidation in the RH process more stably, reducing the generation of deoxidation products fundamentally and improving the purity of molten steel.
While preferred embodiments of the present invention have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. Therefore, it is intended that the appended claims be interpreted as including preferred embodiments and all such alterations and modifications as fall within the scope of the invention. It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.
Claims (10)
1. A method of smelting non-sedating molten steel, characterized by: the method comprises the following steps:
tapping the non-killed steel of the converter;
the non-sedated molten steel enters an LF furnace to be heated;
the heated non-sedated molten steel enters an RH procedure to carry out decarburization reaction;
oxygen is determined, and a deoxidizing agent is added to finish the decarburization reaction;
and (4) deoxidizing and alloying.
2. The method of smelting molten steel of claim 1, wherein: when the temperature is raised in the LF furnace, the temperature is raised to meet the treatment requirement of an RH procedure.
3. The method of smelting molten steel of claim 1, wherein: and after the temperature rise in the LF furnace is finished, carrying out slag modification operation on the non-sedated molten steel in the LF furnace.
4. The method of smelting molten steel of claim 3, wherein: the slag modification operation steps are as follows: the slag modification operation is carried out by using aluminum particles or aluminum slag.
5. The method of smelting molten steel of claim 1, wherein: and when the non-sedated molten steel enters the RH procedure, temperature measurement and oxygen determination are carried out.
6. The method of smelting molten steel of claim 5, wherein: after the temperature measurement and oxygen determination operation, if the carbon content of the molten steel is high or low, vacuumizing to perform decarburization reaction; if the molten steel has high oxygen and low carbon, carbon powder is pre-added for pre-deoxidation and then decarburization reaction is carried out.
7. The method of smelting molten steel of claim 6, wherein: the pre-carbon powder adding step is as follows: and jacking the steel ladle until the dip pipe is inserted into the molten steel surface, and adding the carbon powder into a vacuum tank for vacuum operation.
8. The method of smelting molten steel of claim 1, wherein: and judging whether the decarburization reaction in the RH process is in a gentle trend according to the decarburization time or the CO value in the gas analyzer, and performing oxygen determination operation when the decarburization reaction is in the gentle trend.
9. The method of smelting molten steel of claim 1, wherein: the deoxidation alloying is as follows: according to the change of oxygen level, the carbon consumption of the decarburization reaction is calculated, and carbon powder and ferroalloy are added.
10. The method of smelting molten steel of claim 1, wherein: the molten steel temperature during non-sedated tapping of the converter is 1620 ℃ to 1650 ℃, the molten steel temperature entering the RH process is 1610 ℃ to 1630 ℃, and the oxygen activity is 300 ℃ to 600 ppm.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN106893800A (en) * | 2017-04-06 | 2017-06-27 | 首钢总公司 | A kind of method of deoxidation |
| CN108660287A (en) * | 2018-07-02 | 2018-10-16 | 邯郸钢铁集团有限责任公司 | A kind of LF stoves steel scrap adding set and adding method |
| CN112680557A (en) * | 2020-12-25 | 2021-04-20 | 唐山燕山钢铁有限公司 | Dephosphorization method for smelting ultra-low phosphorus steel |
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