CN115287410B - RH powder spraying vacuum refining device and refining method thereof - Google Patents
RH powder spraying vacuum refining device and refining method thereof Download PDFInfo
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- CN115287410B CN115287410B CN202210954147.9A CN202210954147A CN115287410B CN 115287410 B CN115287410 B CN 115287410B CN 202210954147 A CN202210954147 A CN 202210954147A CN 115287410 B CN115287410 B CN 115287410B
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- 239000000843 powder Substances 0.000 title claims abstract description 260
- 238000005507 spraying Methods 0.000 title claims abstract description 146
- 238000007670 refining Methods 0.000 title claims abstract description 76
- 238000000034 method Methods 0.000 title claims abstract description 56
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 187
- 239000010959 steel Substances 0.000 claims abstract description 187
- 239000012159 carrier gas Substances 0.000 claims abstract description 72
- 239000007789 gas Substances 0.000 claims abstract description 50
- 239000011593 sulfur Substances 0.000 claims abstract description 25
- 229910052717 sulfur Inorganic materials 0.000 claims abstract description 25
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 claims abstract description 23
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 claims abstract description 23
- 239000011574 phosphorus Substances 0.000 claims abstract description 23
- 229910052698 phosphorus Inorganic materials 0.000 claims abstract description 23
- 238000006477 desulfuration reaction Methods 0.000 claims abstract description 21
- 230000023556 desulfurization Effects 0.000 claims abstract description 21
- 238000006243 chemical reaction Methods 0.000 claims abstract description 10
- 229910052760 oxygen Inorganic materials 0.000 claims description 35
- 239000000956 alloy Substances 0.000 claims description 32
- 229910045601 alloy Inorganic materials 0.000 claims description 31
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 30
- 239000001301 oxygen Substances 0.000 claims description 30
- 238000002347 injection Methods 0.000 claims description 12
- 239000007924 injection Substances 0.000 claims description 12
- 238000005070 sampling Methods 0.000 claims description 11
- 238000009529 body temperature measurement Methods 0.000 claims description 8
- 239000007788 liquid Substances 0.000 claims description 7
- 229910052757 nitrogen Inorganic materials 0.000 claims description 7
- 230000001590 oxidative effect Effects 0.000 claims description 5
- 230000001502 supplementing effect Effects 0.000 claims description 3
- 238000012360 testing method Methods 0.000 claims description 3
- 238000007664 blowing Methods 0.000 abstract description 12
- 230000000630 rising effect Effects 0.000 abstract description 7
- 238000003723 Smelting Methods 0.000 abstract description 2
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 8
- 239000000203 mixture Substances 0.000 description 7
- 239000002245 particle Substances 0.000 description 7
- 239000011572 manganese Substances 0.000 description 6
- 239000002436 steel type Substances 0.000 description 6
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 description 3
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 3
- 229910052782 aluminium Inorganic materials 0.000 description 3
- 230000003009 desulfurizing effect Effects 0.000 description 3
- 229910052748 manganese Inorganic materials 0.000 description 3
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 2
- 238000005299 abrasion Methods 0.000 description 2
- 229910052786 argon Inorganic materials 0.000 description 2
- 230000001174 ascending effect Effects 0.000 description 2
- 238000007872 degassing Methods 0.000 description 2
- 238000013461 design Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 239000001257 hydrogen Substances 0.000 description 2
- 229910052739 hydrogen Inorganic materials 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 238000005272 metallurgy Methods 0.000 description 2
- 230000006911 nucleation Effects 0.000 description 2
- 238000010899 nucleation Methods 0.000 description 2
- 238000005275 alloying Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000009851 ferrous metallurgy Methods 0.000 description 1
- 230000005484 gravity Effects 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- -1 inclusion Substances 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 238000004904 shortening Methods 0.000 description 1
- 239000002893 slag Substances 0.000 description 1
- 239000007921 spray Substances 0.000 description 1
- 238000006467 substitution reaction 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
- C21C7/10—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
- C21C1/00—Refining of pig-iron; Cast iron
- C21C1/02—Dephosphorising or desulfurising
-
- 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
- C21C7/064—Dephosphorising; Desulfurising
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
Abstract
The invention belongs to the technical field of steel smelting, and particularly relates to an RH powder spraying vacuum refining device and a refining method thereof. The RH powder spraying vacuum refining device comprises a vacuum chamber, a top blowing gun and a steel ladle, wherein a rising pipe and a falling pipe are arranged at the bottom of the vacuum chamber, a powder spraying gun is arranged on the side wall of the lower portion of the vacuum chamber on one side of the rising pipe, the outlet end of the powder spraying gun is positioned inside the vacuum chamber, a lifting gas channel is arranged at the lower portion of the rising pipe, and the outlet end of the lifting gas channel is positioned below the outlet end of the powder spraying gun. The invention adopts the technical scheme that a powder gun is arranged on the side wall of the lower part of a vacuum chamber at one side of a rising pipe, a lifting gas channel is arranged at the lower part of the rising pipe, and O is used in the RH refining process 2 、CO 2 、N 2 Ar single-component or multi-component gas is used as carrier gas, powder is directly sprayed into the molten steel, the refining period is shortened by 1-3 min compared with the prior RH top powder spraying, the carrier gas and the powder flow along with the molten steel and are subjected to dephosphorization and desulfurization reaction with the molten steel, so that the phosphorus and sulfur in the molten steel are reduced to target contents, and the purity of the molten steel is improved.
Description
Technical Field
The invention belongs to the technical field of steel smelting, and particularly relates to an RH powder spraying vacuum refining device and a refining method thereof.
Background
RH refining is commonly referred to as RH vacuum cycle degassing refining. Was invented by german in 1959, where RH is the first letter of two manufacturers in germany at that time using RH refining technology. The existing RH vacuum refining technology has various metallurgical functions such as degassing, deoxidizing, decarburizing, desulfurizing, component fine tuning, heating and the like. The RH treatment effect is good, the functions are multiple, the treatment speed is high, and the treatment batch is large, so that the method is particularly suitable for the fast pace of modern ferrous metallurgy enterprises. Thus, RH is rapidly developed, and treatment is initially performed to ensure only a small amount of special steel quality, and is now developed into a large amount of molten steel treatment process for most steel grades. The traditional RH refining process enables the block slag-making material to fall into the surface of molten steel from a bin above a vacuum chamber by self gravity to carry out dephosphorization and desulfurization reaction and alloying, but after entering a steel ladle along with the molten steel, the block material quickly floats up to enter slag above the steel ladle, so that dephosphorization and desulfurization efficiency is very low, and phosphorus and sulfur are difficult to be removed to target values of variety steel.
With the development of various industries, the requirements on the purity of steel types are higher and higher, and an RH powder spraying process is generated. And sulfur in molten steel is removed by using an RH top powder spraying process, so that the purpose of reducing the sulfur content is achieved. The RH top powder spraying process has the defects that: (1) The desulfurization powder has low utilization rate, and a large amount of powder is pumped away under the action of vacuumizing, so that the desulfurization powder cannot enter molten steel and is effectively utilized; (2) The vacuum system equipment is affected by the powder, is easy to wear and has low working efficiency; (3) The top powder spraying gun is easy to burn, the powder yield is too low when the gun position is too high, and the sprayed molten steel is easy to burn when the gun position is too low; (4) The top powder spraying process is unfavorable for dephosphorization, carrier gas of the process is argon, the oxygen content of a region where powder is contacted with molten steel is low, and the process does not have thermodynamic conditions of dephosphorization; (5) The low powder effective utilization rate causes a large amount of carrier gas requirements, and a large amount of carrier gas conveying causes the molten steel Wen Jiangliang to be greatly increased, so that the refining cost is improved.
Patent application number 201811480907.7 discloses a RH refining rotary powder spraying dephosphorization method, which utilizes a top blowing rotary gun to insert 400-650mm below the liquid level of steel, and directly sprays powder into the liquid steel with carrier gas Ar. How to simultaneously realize the high-efficiency refining of the clean steel with ultralow phosphorus content and ultralow sulfur content, and improve the quality of molten steel while shortening the refining period becomes a difficult problem to be solved in the steel industry.
Disclosure of Invention
Aiming at the problems, the invention aims to provide an RH powder spraying vacuum refining device and a refining method thereof, compared with the prior RH top powder spraying refining period, the refining method shortens 1-3 min, the terminal sulfur content and the phosphorus content can be stabilized below 10ppm, the purity of molten steel is improved, the powder effective yield of the refining method is high, the terminal components are stabilized, the aim of ultra-low phosphorus and ultra-low sulfur refining can be simultaneously achieved, the refining period is short, and the heat loss is low.
The technical scheme of the invention is as follows: the utility model provides a RH powder spraying vacuum refining device, includes vacuum chamber, top-blown rifle and ladle, the top-blown rifle inserts the inside top of vacuum chamber, the vacuum chamber bottom is equipped with tedge and downcomer, tedge and downcomer insert respectively in the ladle and with the inside intercommunication of ladle, the lower part lateral wall of tedge one side vacuum chamber is equipped with the powder gun, the exit end of powder gun is located inside the vacuum chamber, the entry end of powder gun is connected with powder gas conveying pipeline, the lower part of tedge is equipped with promotion gas passage, the exit end of promotion gas passage is located the below of powder gun exit end.
And an alloy chute is arranged on the side wall above the vacuum chamber.
The number of the powder spraying guns is 1-4.
The lifting gas channel is connected with a gas source valve station.
An RH powder spraying vacuum refining method, which uses any RH powder spraying vacuum refining device as described above, comprises the following steps:
s1: during refining treatment, the ladle is lifted to a design position, and lifting gas in a lifting gas channel is formed by N 2 Switching to Ar, wherein the powder spraying carrier gas in the powder spraying gun is formed by N 2 Switching to Ar, measuring the temperature of molten steel in the ladle, and sampling, and testing the temperature, the initial phosphorus content and the initial sulfur content of the molten steel;
s2: starting a vacuum pump to vacuumize the vacuum chamber, enabling molten steel to form circulating flow in the vacuum chamber and the steel ladle, measuring temperature and determining oxygen when the vacuum degree of the vacuum chamber reaches 100-10000 Pa, adding corresponding deoxidized alloy amount according to the oxygen content of the molten steel, and adding corresponding alloy amount according to the initial and target difference value of the alloy elements; the method comprises the steps of carrying out a first treatment on the surface of the
S3: after the alloy is added, after the molten steel circulates for 1-10 min, the powder spraying carrier gas in the powder spraying gun is switched into mixed carrier gas, after the mixed carrier gas is stably sprayed into the molten steel from the side surface of the lower end of the vacuum chamber, powder is blown into the molten steel, the powder flows along with the molten steel in a circulating way and participates in metallurgical reaction, powder spraying is stopped after powder spraying treatment for 1-12 min, and the powder spraying carrier gas in the powder spraying gun is switched into Ar;
s4: carrying out temperature measurement sampling operation on molten steel, supplementing alloy according to the phosphorus/sulfur content, the alloy element content and the molten steel temperature of the molten steel, and regulating the temperature through scrap steel;
s5: the molten steel circulates for reaching the preset time, the breaking operation is carried out, the steel ladle descends, and the lifting gas in the lifting gas channel and the powder spraying carrier gas in the powder spraying gun are switched into N with preset flow 2 And finishing refining.
In the step S3, in the powder injection process, the carrier gas is an oxidizing gas comprising O 2 、CO 2 、Ar、N 2 The powder comprises dephosphorization synthetic powder and desulfurization synthetic powder, and the dephosphorization powder comprises CaO and CaCO 3 One or more of the powders, the desulphurised synthetic powders comprising one or more of the CaO, caF, mg powders.
In the step S3, the selection operation of the powder spraying carrier gas in the powder spraying gun is as follows:
when the target steel grade is ultra-low phosphorus steel, the phosphorus content is less than or equal to 0.005%, and the powder spraying carrier gas in the powder spraying gun selects O 2 +CO 2 +Ar, wherein the mass ratio of the powder to the powder spraying carrier gas is 3-40, the oxidizing property of molten steel near the powder is increased, the powder is selected to dephosphorize the powder, and the powder spraying dephosphorization operation is carried out;
when the target steel grade is ultralow-sulfur steel, the sulfur content is less than or equal to 0.002%, and the powder spraying carrier gas in the powder spraying gun selects Ar+CO 2 The mass ratio of the powder to the powder spraying carrier gas is 3-40, the circulating flow of molten steel is increased, the powder selects desulfurization powder, and the powder spraying desulfurization operation is carried out;
when the target steel grade simultaneously needs ultra-low phosphorus content and ultra-low sulfur content, performing powder spraying dephosphorization operation, measuring temperature and determining oxygen after dephosphorization is finished, adding alloy, and performing powder spraying desulfurization operation.
In the steps S2 to S3, the vacuum degree of the vacuum chamber is kept at 100 to 10000Pa.
In the step S3, the total flow of the powder spraying carrier gas in the powder spraying gun is 50-1000 Nm 3 And/h, ensuring that the outlet pressure of a powder gun in the vacuum refining process of the molten steel is more than or equal to 0.2MPa.
And when the molten steel circulates in the step S3, the outlet of the powder spraying gun is positioned below the liquid level of the molten steel at the lower end of the vacuum chamber.
The invention has the technical effects that: 1. according to the invention, the powder gun is arranged at the lower part of the side wall of the vacuum chamber at one side of the rising pipe, the lifting gas channel is arranged at the middle lower part of the rising pipe, powder can be directly sprayed into molten steel in the RH refining process, the period is shortened by 1-3 min compared with the current RH top powder spraying refining period, carrier gas and powder flow along with the molten steel and dephosphorization and desulfurization reactions are carried out on the carrier gas and the powder and the molten steel, phosphorus and sulfur in the molten steel are reduced to target contents, powder particles are taken as nucleation centers in the process of flowing along with the molten steel, inclusion, nitrogen, hydrogen and other gases in the molten steel are effectively removed, the terminal sulfur content and phosphorus content can reach below 10ppm steadily, and the purity of the molten steel is improved; 2. when the molten steel is circulated, the outlet of the powder spraying gun is positioned below the liquid level of the molten steel, so that the problems of low powder utilization rate and easiness in abrasion of vacuum equipment are solved, meanwhile, aiming at the requirements of RH refining target steel types, mixed carrier gases with different proportions can be used for directly blowing the powder into the molten steel, and the powder utilization rate is improved; 3. according to the invention, dephosphorization and desulfurization treatment can be realized in the same furnace according to different target steel refining requirements, so that the purity of molten steel is improved, and the refining cost is reduced.
Further description will be made below with reference to the accompanying drawings.
Drawings
Fig. 1 is a schematic structural diagram of an RH-powder-spraying vacuum refining apparatus according to an embodiment of the present invention.
Reference numerals: 1-vacuum chamber, 2-powder gun, 3-riser, 4-lifting gas channel, 5-ladle, 6-molten steel, 7-downcomer, 8-alloy chute, 9-top-blown gun.
Detailed Description
Example 1
As shown in fig. 1, an RH powder spraying vacuum refining device comprises a vacuum chamber 1, a top blowing gun 9 and a ladle 5, wherein the top blowing gun 9 is inserted above the inside of the vacuum chamber 1, a riser 3 and a downcomer 7 are arranged at the bottom of the vacuum chamber 1, the riser 3 and the downcomer 7 are respectively inserted into the ladle 5 and are communicated with the inside of the ladle 5, a powder spraying gun 2 is arranged on the side wall of the lower part of the vacuum chamber 1 on one side of the riser 3, the outlet end of the powder spraying gun 2 is positioned inside the vacuum chamber 1, the inlet end of the powder spraying gun 2 is connected with a powder gas conveying pipeline, a lifting gas channel 4 is arranged at the lower part of the riser 3, and the outlet end of the lifting gas channel 4 is positioned below the outlet end of the powder spraying gun 2.
In the actual use process, the powder gun 2 is arranged on the side wall of the lower part of the vacuum chamber 1 at one side of the ascending pipe 3, the lifting gas channel 4 is arranged at the lower part of the ascending pipe 3, powder can be directly sprayed into molten steel by the powder gun 2 in the RH refining process, the period is shortened by 1-3 min compared with the prior RH top powder spraying refining period, carrier gas and powder flow along with the molten steel and dephosphorize and desulphurize with the molten steel, phosphorus and sulfur in the molten steel are reduced to target contents, powder particles serve as nucleation centers in the flowing process of the powder particles along with the molten steel, the inclusion, nitrogen, hydrogen and other gases in the molten steel are effectively removed, the terminal sulfur content and the phosphorus content can reach below 10ppm, and the purity of the molten steel is improved.
Example 2
Preferably, on the basis of embodiment 1, in this embodiment, an alloy chute 8 is disposed on the upper side wall of the vacuum chamber 1.
In the actual use process, the side wall above the vacuum chamber 1 is provided with the alloy chute 8, and the alloy chute 8 can add alloy materials into molten steel, so that the alloy components of the molten steel meet the target requirements.
Example 3
Preferably, on the basis of embodiment 1 or embodiment 2, in this embodiment, the number of the powder guns 2 is 1 to 4.
In the actual use process, the number of the powder spraying guns 2 is 1-4, and the use number can be determined according to the needs during use, so that the powder spraying needs in the refining process are ensured.
Example 4
Preferably, in this embodiment, on the basis of embodiment 1 or embodiment 3, a gas source valve station is connected to the lifting gas channel 4.
In the actual use process, the lifting gas channel 4 is connected with the gas source valve station, and the gas source valve station can rapidly realize the flow control of lifting gas in the lifting gas channel.
Example 5
An RH powder spraying vacuum refining method, which uses any RH powder spraying vacuum refining device described in the embodiment, comprises the following steps:
s1: during refining treatment, the ladle 5 is lifted to a design position, and the lifting gas in the lifting gas channel 4 is formed by N 2 Switching to Ar, the powder spraying carrier gas in the powder spraying gun 2 is formed by N 2 Switching to Ar, measuring the temperature of the molten steel 6 in the ladle 5, and sampling, and testing the temperature, the initial phosphorus content and the initial sulfur content of the molten steel 6;
s2: starting a vacuum pump to vacuumize the vacuum chamber 1, enabling molten steel 6 to form circulating flow in the vacuum chamber 1 and the steel ladle 5, measuring temperature and determining oxygen when the vacuum degree of the vacuum chamber 1 reaches 100-10000 Pa, adding corresponding deoxidized alloy amount according to the oxygen content of the molten steel 6, and adding corresponding alloy amount according to the initial and target difference value of the alloy elements;
s3: after the alloy is added, after the molten steel 6 circulates for 1-10 min, the powder spraying carrier gas in the powder spraying gun 2 is switched into mixed carrier gas, after the mixed carrier gas is stably sprayed into the molten steel 6 from the side surface of the lower end of the vacuum chamber 1, powder is blown into the molten steel 6, the powder flows along with the molten steel 6 in a circulating way and participates in metallurgical reaction, the powder spraying is stopped after the powder spraying treatment is carried out for 1-12 min, and the powder spraying carrier gas in the powder spraying gun 2 is switched into Ar;
s4: carrying out temperature measurement sampling operation on the molten steel 6, supplementing and adding alloy according to the phosphorus/sulfur content, the alloy element content and the molten steel temperature of the molten steel 6, and adjusting the temperature through scrap steel;
s5: the molten steel 6 circulates for reaching the preset time, the breaking operation is carried out, the steel ladle 5 descends, and the lifting gas in the lifting gas channel 4 and the powder spraying carrier gas in the powder spraying gun 2 are switched into N with the preset flow rate 2 And finishing refining.
In the step S3, in the powder injection process, the carrier gas is an oxidizing gas comprising O 2 、CO 2 、Ar、N 2 The powder comprises dephosphorization synthetic powder and desulfurization synthetic powder, and the dephosphorization powder comprises CaO and CaCO 3 One or more of the powders, the desulphurised synthetic powders comprising one or more of the CaO, caF, mg powders.
In the step S3, the selection operation of the powder spraying carrier gas in the powder spraying gun 2 is as follows:
when the target steel grade is ultra-low phosphorus steel, the powder spraying carrier gas in the powder spraying gun 2 selects O 2 +CO 2 +Ar, wherein the mass ratio of the powder to the powder spraying carrier gas is 3-40, the oxidizing property of molten steel near the powder is increased, the powder is selected to dephosphorize the powder, and the powder spraying dephosphorization operation is carried out;
when the target steel grade is ultra-low sulfur steel, the powder spraying carrier gas in the powder spraying gun 2 selects Ar+CO 2 The mass ratio of the powder to the powder spraying carrier gas is 3-40, the circulating flow of molten steel is increased, the powder selects desulfurization powder, and the powder spraying desulfurization operation is carried out;
when the target steel grade simultaneously needs ultra-low phosphorus content and ultra-low sulfur content, performing powder spraying dephosphorization operation, measuring temperature and determining oxygen after dephosphorization is finished, adding alloy, and performing powder spraying desulfurization operation.
According to the invention, aiming at the requirements of RH refining target steel types, mixed carrier gases with different proportions are used for directly blowing powder into molten steel, so that the utilization rate of the powder is improved; and dephosphorization and desulfurization treatment are realized in the same furnace, so that the purity of molten steel is improved, and meanwhile, the refining cost is reduced.
In the steps S2 to S3, the vacuum degree of the vacuum chamber 1 is kept at 100 to 10000Pa.
In the step S3, the total flow of the powder spraying carrier gas in the powder spraying gun 2 is 50-1000 Nm 3 And/h, ensuring that the outlet pressure of the powder gun 2 in the vacuum refining process of the molten steel 6 is more than or equal to 0.2MPa.
The total flow of the powder spraying carrier gas in the powder spraying gun 2 is 100-1000 Nm 3 And/h, ensuring that the outlet pressure of the powder gun 2 of the molten steel 6 in the vacuum refining process is more than or equal to 0.2MPa, and preventing the molten steel from flowing backwards to cause productionAn accident.
In the step S3, when the molten steel 6 circulates, the outlet of the powder gun 2 is positioned below the liquid level of the molten steel 6 at the lower end of the vacuum chamber 1.
When the molten steel 6 circulates, the outlet of the powder spraying gun 2 is positioned below the liquid level of the molten steel 6, so that the problems of low powder utilization rate, easiness in abrasion of vacuum equipment and complex powder spraying equipment are solved.
Example 6
The RH powder spraying vacuum refining device is adopted as in the embodiment 1, the RH powder spraying vacuum refining method is adopted as in the embodiment 5, and the specific process of the 300 ton RH powder spraying vacuum refining pure steel comprises the following steps:
s1: after the steel ladle enters the station, jacking the steel ladle to a preset position, wherein the lifting gas flow is 50-80 Nm 3 N of/h 2 Switching to 80-120 Nm 3 Ar/h, switching the flow rate of the powder spraying carrier gas to 50-80 Nm 3 N of/h 2 Switching to 50-100 Nm 3 Ar of/h, carrying out temperature measurement and sampling;
s2: starting a vacuum pump to vacuumize, so that molten steel forms circulating flow in a vacuum chamber and a steel ladle, wherein the weight of the molten steel is 300 tons, and the compositions of the incoming molten steel and the target steel type are shown in table 1:
TABLE 1 example 6 inbound molten steel composition and target Steel grade composition
| Project | [C]% | [Mn]% | [S]% | [P]% | [O]% | [N]% |
| Inbound station | 0.035 | 0.050 | 0.0051 | 0.0080 | 0.0750 | 0.0025 |
| Target object | 0.005 | 0.205 | 0.0050 | 0.0010 | 0.0011 | 0.0015 |
When the vacuum degree reaches 100-10000 Pa, measuring temperature and oxygen, wherein the temperature of molten steel is 1575 ℃, performing top lance oxygen blowing operation according to the temperature oxygen position, and the lance position is 3500-4000 mm and the oxygen blowing amount is 300-350 Nm 3 ；
S3: when molten steel circulates for 5min, the carrier gas of the powder spraying pipeline is automatically switched to 50% CO 2 +50%O 2 The total flow of carrier gas is 120-150 Nm 3 After carrier gas is stably sprayed into molten steel from the side surface of the lower end of the vacuum chamber, dephosphorizing powder with the particle size of 0.1-1mm is blown into the molten steel, the powder flows along with the molten steel in a circulating way to participate in dephosphorizing metallurgical reaction, the powder spraying speed is 140-180 kg/min, the powder spraying process is carried out, the vacuum degree is kept at 4000-6000 Pa, the powder spraying is stopped after 10min, and the carrier gas is switched to 50-100 Nm 3 /h Ar；
S4: adding electrolytic aluminum for deoxidization, measuring temperature and oxygen after molten steel circulates for 3min, adding 650-700 kg of electrolytic manganese through an alloy chute, measuring temperature and oxygen after molten steel circulates for 3min, and sampling, wherein all components reach the standard;
s5: the molten steel circulates for 25 min to reach the preset value, the steel ladle descends, and the lifting gas is switched to 50-80 Nm 3 Nitrogen per hour, and carrier gas is switched to 50-100 Nm 3 N of the flow rate/h 2 And finishing refining.
Example 7
The RH powder spraying vacuum refining device is adopted as in the embodiment 1, the RH powder spraying vacuum refining method is adopted as in the embodiment 5, and the specific process of the 200 ton RH powder spraying vacuum refining pure steel comprises the following steps:
s1: after the steel ladle enters the station, jacking the steel ladle to a preset position, wherein the lifting gas flow is 50-80 Nm 3 N of/h 2 Switching to 120-150 Nm 3 Ar/h, switching the flow rate of the powder spraying carrier gas to 50-100 Nm 3 N of/h 2 Switching to 50-100 Nm 3 Ar of/h, carrying out temperature measurement and sampling;
s2: starting a vacuum pump to vacuumize, so that molten steel forms circulating flow in a vacuum chamber and a steel ladle, wherein the weight of the molten steel is 200 tons, and the compositions of the incoming molten steel and the target steel type are shown in Table 2:
TABLE 2 example 7 compositions of incoming molten steel and target Steel grade
| Project | [C]% | [Mn]% | [S]% | [P]% | [O]% | [N]% |
| Inbound station | 0.032 | 0.050 | 0.0051 | 0.0080 | 0.0700 | 0.0029 |
| Target object | 0.002 | 0.255 | 0.0010 | 0.0100 | 0.0010 | 0.0015 |
When the vacuum degree reaches 100-10000 Pa, measuring temperature and oxygen, wherein the temperature of molten steel is 1570 ℃, performing top lance oxygen blowing operation according to the temperature oxygen position, the lance position is 3500-4000 mm, and the oxygen blowing amount is 300-350 Nm 3 After molten steel circulates for 5min, electrolytic aluminum is added for deoxidization, and after molten steel circulates for 3min, temperature measurement and oxygen determination are carried out;
s3: carrier gas of the powder spraying pipeline is automatically switched to 30% CO 2 +70% Ar, the total flow of carrier gas is 120-150 Nm 3 After the carrier gas is stably sprayed into the molten steel from the side surface of the lower end of the vacuum chamber, desulfurizing powder with the particle size of 0.1-1 and mm is blown into the molten steel, the powder flows along with the molten steel in a circulating way to participate in desulfurization metallurgy reaction, the powder spraying speed is 150-180 kg/min, the powder spraying process is carried out, the vacuum degree is kept at 4000-6000 Pa, the powder spraying is stopped after the powder spraying is carried out for 7 min, and the carrier gas is switched to 50-100 Nm 3 Ar of/h;
s4: measuring temperature and oxygen, adding 570-600 kg of electrolytic manganese through an alloy chute, circulating molten steel for 3min, measuring temperature and oxygen, sampling, and enabling all components to reach the standard;
s5: the molten steel circulates for 22min to reach the preset value, the breaking operation is carried out, the steel ladle descends, and the lifting gas is switched to 50-80 Nm 3 Nitrogen per hour, and carrier gas is switched to 50-100 Nm 3 N of the flow rate/h 2 And finishing refining.
Example 8
The RH powder spraying vacuum refining device is adopted as in the embodiment 1, the RH powder spraying vacuum refining method is adopted as in the embodiment 5, and the concrete process of the 150 ton RH powder spraying vacuum refining pure steel comprises the following steps:
s1: after the steel ladle enters the station, jacking the steel ladle to a preset position, wherein the lifting gas flow is 50-80 Nm 3 N of/h 2 Switching to 120-150 Nm 3 Ar/h, switching the flow rate of the powder spraying carrier gas to 50-100 Nm 3 N of/h 2 Switching to 50-100 Nm 3 Ar of/h, carrying out temperature measurement and sampling;
s2: starting a vacuum pump to vacuumize, so that molten steel forms circulating flow in a vacuum chamber and a steel ladle, wherein the weight of the molten steel is 150 tons, and the compositions of the incoming molten steel and the target steel type are shown in Table 3:
TABLE 3 example 8 compositions of incoming molten steel and target Steel grade
| Project | [C]% | [Mn]% | [S]% | [P]% | [O]% | [N]% |
| Inbound station | 0.032 | 0.050 | 0.0051 | 0.0080 | 0.0700 | 0.0029 |
| Target object | 0.002 | 0.255 | 0.0010 | 0.0010 | 0.0010 | 0.0015 |
When the vacuum degree reaches 100-10000 Pa, measuring temperature and oxygen, wherein the temperature of molten steel is 1580 ℃, performing top lance oxygen blowing operation according to the temperature oxygen position, wherein the lance position is 4000-5000 mm, and the oxygen blowing amount is 200-250 Nm 3 ；
S3: firstly, powder spraying dephosphorization is carried out, and when molten steel circulates for 5min, the carrier gas of a powder spraying pipeline is automatically switched into 60 percent CO 2 +40%O 2 The total flow of carrier gas is 120-150 Nm 3 After carrier gas is stably sprayed into molten steel from the side surface of the lower end of the vacuum chamber, dephosphorizing powder with the particle size of 0.1-1 and mm is blown into the molten steel, the powder flows along with the molten steel in a circulating way to participate in dephosphorizing metallurgical reaction, the powder spraying speed is 150-180 kg/min, the powder spraying process is carried out, the vacuum degree is kept at 3000-6000 Pa, the powder spraying is stopped after the powder spraying is carried out for 8 min, and the carrier gas is switched to 50-80 Nm 3 H Ar; after 2min of circulation, 200 kg electrolytic aluminum is added for deoxidization, and after 2min of molten steel circulation, temperature measurement and oxygen determination are carried out. The carrier gas of the powder spraying pipeline is automatically switched to flow of 120-150 Nm 3 Ar of/h, after carrier gas is stably sprayed into molten steel from the side surface of the lower end of a vacuum chamber, desulfurizing powder with the particle size of 0.1-1mm is blown into the molten steel, the powder flows along with the molten steel in a circulating way to participate in desulfurization metallurgy reaction, the powder spraying speed is 140-160 kg/min, the powder spraying process is carried out, the vacuum degree is kept at 3000-6000 Pa, the powder spraying is stopped after the powder spraying is carried out for 9 min, and the carrier gas is switched to 50-100 Nm 3 Ar of/h;
s4: measuring temperature and oxygen, adding 430 kg electrolytic manganese through an alloy chute, circulating molten steel for 3min, measuring temperature and oxygen, sampling, and enabling all components to reach the standard;
s5: the molten steel circulates for 50min to reach the preset value, the breaking operation is carried out, the steel ladle descends, and the lifting gas is switched to 50-80 Nm 3 N of/h 2 The carrier gas is switched to 50-100 Nm 3 N of the flow rate/h 2 And finishing refining.
The present invention is not limited to the above-mentioned embodiments, and any changes or substitutions that can be easily understood by those skilled in the art within the technical scope of the present invention are intended to be included in the scope of the present invention.
Claims (9)
1. An RH powder spraying vacuum refining method is characterized in that: use a RH powder injection vacuum refining device, the device includes vacuum chamber (1), top-blown rifle (9) and ladle (5), top-blown rifle (9) are inserted vacuum chamber (1) inside top, vacuum chamber (1) bottom is equipped with tedge (3) and downcomer (7), tedge (3) and downcomer (7) are inserted respectively in ladle (5) and with ladle (5) inside intercommunication, the lower part lateral wall of tedge (3) one side vacuum chamber (1) is equipped with powder gun (2), the exit end of powder gun (2) is located vacuum chamber (1) inside, the entry end of powder gun (2) is connected with powder gas delivery pipeline, the lower part of tedge (3) is equipped with promotion gas channel (4), the exit end of promotion gas channel (4) is located the below of powder gun (2) exit end, specifically includes the following steps:
s1: during refining treatment, the ladle (5) is lifted to a designed position, and lifting gas in the lifting gas channel (4) is formed by N 2 Ar is switched, and the powder spraying carrier gas in the powder spraying gun (2) is formed by N 2 Switching to Ar, measuring the temperature of the molten steel (6) in the ladle (5), and testing the temperature, the initial phosphorus content and the initial sulfur content of the molten steel (6);
s2: starting a vacuum pump to vacuumize the vacuum chamber (1) so that molten steel (6) forms circulation flow in the vacuum chamber (1) and the steel ladle (5), measuring temperature and determining oxygen when the vacuum degree of the vacuum chamber (1) reaches 100-10000 Pa, adding corresponding deoxidized alloy amount according to the oxygen content of the molten steel (6), and adding corresponding alloy amount according to the initial and target difference values of the alloy elements;
s3: after the alloy is added, after the molten steel (6) circulates for 1-10 min, the powder spraying carrier gas in the powder spraying gun (2) is switched into mixed carrier gas, after the mixed carrier gas is stably sprayed into the molten steel (6) from the side surface of the lower end of the vacuum chamber (1), powder is blown into the molten steel (6), the powder flows along with the molten steel (6) in a circulating way and participates in metallurgical reaction, the powder spraying is stopped after the powder spraying treatment for 1-12 min, and the powder spraying carrier gas in the powder spraying gun (2) is switched into Ar;
s4: carrying out temperature measurement sampling operation on the molten steel (6), supplementing and adding alloy according to the phosphorus/sulfur content, the alloy element content and the molten steel temperature of the molten steel (6), and adjusting the temperature through scrap steel;
s5: the molten steel (6) circulates for reaching the preset time, the steel ladle (5) descends, and the lifting gas in the lifting gas channel (4) and the powder spraying carrier gas in the powder spraying gun (2) are switched into N with the preset flow rate 2 And finishing refining.
2. The RH powder injection vacuum refining process of claim 1, wherein: an alloy chute (8) is arranged on the side wall above the vacuum chamber (1).
3. The RH powder injection vacuum refining process of claim 1, wherein: the number of the powder spraying guns (2) is 1-4.
4. The RH powder injection vacuum refining process of claim 1, wherein: and the inlet end of the lifting gas channel (4) is connected with a gas source valve station.
5. The RH powder injection vacuum refining process of claim 1, wherein:in the step S3, in the powder injection process, the carrier gas is an oxidizing gas comprising O 2 、CO 2 、Ar、N 2 The powder comprises dephosphorization synthetic powder and desulfurization synthetic powder, the dephosphorization synthetic powder comprises CaO and CaCO 3 One or more of the powders, the desulphurised synthetic powders comprising one or more of the CaO, caF, mg powders.
6. The RH powder injection vacuum refining process of claim 1, wherein: in the step S3, the selection operation of the powder spraying carrier gas in the powder spraying gun (2) is as follows:
when the target steel grade is ultra-low phosphorus steel, the phosphorus content is less than or equal to 0.005%, and the powder spraying carrier gas in the powder spraying gun (2) selects O 2 +CO 2 +Ar, wherein the mass ratio of the powder to the powder spraying carrier gas is 3-40, the powder is selected to be dephosphorized into powder for increasing the oxidability of molten steel near the powder, and the powder spraying dephosphorization operation is carried out;
when the target steel grade is ultralow-sulfur steel, the sulfur content is less than or equal to 0.002%, and the powder spraying carrier gas in the powder spraying gun (2) selects Ar+CO 2 The mass ratio of the powder to the powder spraying carrier gas is 3-40, the circulating flow of molten steel is increased, the powder is selected to desulfurize and synthesize powder, and the powder spraying desulfurization operation is carried out;
when the target steel grade simultaneously needs ultra-low phosphorus content and ultra-low sulfur content, performing powder spraying dephosphorization operation, measuring temperature and determining oxygen after dephosphorization is finished, adding alloy, and performing powder spraying desulfurization operation.
7. The RH powder injection vacuum refining process of claim 1, wherein: in the steps S2 to S3, the vacuum degree of the vacuum chamber (1) is kept at 100 to 10000Pa.
8. The RH powder injection vacuum refining process of claim 1, wherein: in the step S3, the total flow of the powder spraying carrier gas in the powder spraying gun (2) is 50-1000 Nm 3 And/h, ensuring that the outlet pressure of the powder gun (2) in the vacuum refining process of the molten steel (6) is more than or equal to 0.2MPa.
9. The RH powder injection vacuum refining process of claim 1, wherein: and when the molten steel (6) circulates in the step S3, the outlet of the powder spraying gun (2) is positioned below the liquid level of the molten steel (6) at the lower end of the vacuum chamber (1).
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| JPH01246314A (en) * | 1988-03-29 | 1989-10-02 | Kawasaki Steel Corp | Production of extremely low carbon steel by vacuum degassing treatment |
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| CN108699614A (en) * | 2016-02-24 | 2018-10-23 | 杰富意钢铁株式会社 | The method of refining of molten steel in vacuum deaerator plant |
| CN112111625A (en) * | 2020-09-07 | 2020-12-22 | 钢铁研究总院 | RH vacuum powder injection refining device and powder injection method thereof |
| CN112501392A (en) * | 2020-10-13 | 2021-03-16 | 河北敬业精密制管有限公司 | Dehydrogenation method and device for RH furnace |
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| JPH01246314A (en) * | 1988-03-29 | 1989-10-02 | Kawasaki Steel Corp | Production of extremely low carbon steel by vacuum degassing treatment |
| CN2432219Y (en) * | 2000-06-09 | 2001-05-30 | 北京科技大学 | Multifunctional multiple blowing single nozzle refining furnace |
| CN102560009A (en) * | 2012-01-16 | 2012-07-11 | 东北大学 | RH vacuum refining bottom blowing powder injection device |
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