CN115287410A - RH powder injection vacuum refining device and refining method thereof - Google Patents
RH powder injection vacuum refining device and refining method thereof Download PDFInfo
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- 239000000843 powder Substances 0.000 title claims abstract description 249
- 238000007670 refining Methods 0.000 title claims abstract description 82
- 238000000034 method Methods 0.000 title claims abstract description 56
- 238000002347 injection Methods 0.000 title claims abstract description 46
- 239000007924 injection Substances 0.000 title claims abstract description 46
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 188
- 239000010959 steel Substances 0.000 claims abstract description 188
- 238000005507 spraying Methods 0.000 claims abstract description 96
- 239000012159 carrier gas Substances 0.000 claims abstract description 71
- 239000007789 gas Substances 0.000 claims abstract description 47
- 230000008569 process Effects 0.000 claims abstract description 32
- 239000011593 sulfur Substances 0.000 claims abstract description 25
- 229910052717 sulfur Inorganic materials 0.000 claims abstract description 25
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 claims abstract description 24
- 238000007664 blowing Methods 0.000 claims abstract description 23
- 229910052698 phosphorus Inorganic materials 0.000 claims abstract description 23
- 239000011574 phosphorus Substances 0.000 claims abstract description 23
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 claims abstract description 22
- 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 15
- 230000001174 ascending effect Effects 0.000 claims abstract description 14
- 229940098458 powder spray Drugs 0.000 claims abstract description 9
- 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
- 238000005070 sampling Methods 0.000 claims description 12
- 238000009529 body temperature measurement Methods 0.000 claims description 6
- 239000007788 liquid Substances 0.000 claims description 6
- 229910052757 nitrogen Inorganic materials 0.000 claims description 5
- 230000015572 biosynthetic process Effects 0.000 claims description 3
- 230000003009 desulfurizing effect Effects 0.000 claims description 3
- 230000001590 oxidative effect Effects 0.000 claims description 3
- 230000001502 supplementing effect Effects 0.000 claims description 3
- 238000003786 synthesis reaction Methods 0.000 claims description 3
- 238000003723 Smelting Methods 0.000 abstract description 2
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 6
- 239000011572 manganese Substances 0.000 description 6
- 239000002245 particle Substances 0.000 description 6
- 239000000203 mixture Substances 0.000 description 4
- 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
- 229910052748 manganese Inorganic materials 0.000 description 3
- 239000007921 spray Substances 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
- 230000009286 beneficial effect Effects 0.000 description 2
- 238000007872 degassing Methods 0.000 description 2
- 229910001873 dinitrogen Inorganic materials 0.000 description 2
- 230000000694 effects Effects 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
- 230000006911 nucleation Effects 0.000 description 2
- 238000010899 nucleation Methods 0.000 description 2
- 239000002893 slag Substances 0.000 description 2
- 230000009471 action Effects 0.000 description 1
- 238000005275 alloying Methods 0.000 description 1
- 229910052786 argon Inorganic materials 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005261 decarburization Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000005516 engineering process 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
- 230000006872 improvement Effects 0.000 description 1
- -1 inclusions Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 239000011819 refractory material Substances 0.000 description 1
- 238000004904 shortening Methods 0.000 description 1
- 239000002436 steel type Substances 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/10—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
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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 belongs to the technical field of steel smelting, and particularly relates to an RH powder injection vacuum refining device and a refining method thereof. The utility model provides a RH powder spray vacuum refining device, includes real empty room, top blowing rifle and ladle, and real empty room bottom is equipped with tedge and downcomer, and the real empty room's of tedge lower part lateral wall is equipped with the powder spray gun, and the exit end of powder spray gun is located real empty room inside, and the lower part of tedge is equipped with the lift gas channel, and the exit end that promotes the gas channel is located the below of powder spray gun exit end. The powder gun is arranged on the side wall of the lower part of the vacuum chamber at one side of the ascending pipe, the lifting gas channel is arranged at the lower part of the ascending pipe, and O is used for refining 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 molten steel, and the refining period is shortened by 1 to 3min compared with the prior RH top powder spraying refining periodThe powder flows along with the molten steel and has dephosphorization and desulfurization reactions 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 injection vacuum refining device and a refining method thereof.
Background
RH refining is called RH vacuum circulation degassing refining method. Invented by german in 1959, wherein RH was the first letter of two manufacturers in germany, who used RH refining technology at that time. The existing RH vacuum refining process has various metallurgical functions of degassing, deoxidation, decarburization, desulfurization, component fine adjustment, heating and the like. Because the RH treatment effect is good, the functions are multiple, the treatment speed is high, and the treatment batch size is large, the method is particularly suitable for the fast pace of modern ferrous metallurgy enterprises. Therefore, the RH is developed at a fast speed, and a treatment for securing only a small amount of special steel quality is initially performed, and a large amount of molten steel treatment process for most steel grades is now developed. According to the traditional RH refining process, blocky slag forming materials fall onto the surface of molten steel from a bin above a vacuum chamber by means of self gravity to perform dephosphorization and desulfurization reaction and alloying, but the blocky materials quickly float upwards to enter slag above a steel ladle after entering the steel ladle along with the molten steel, so that the dephosphorization and desulfurization efficiency is very low, and phosphorus and sulfur are difficult to remove to a target value of variety steel.
With the development of various industries, the requirement on the purity of steel grades is higher and higher, and the RH powder spraying process is in operation. The RH top powder spraying process is utilized to remove sulfur in the molten steel, thereby achieving the purpose of reducing the sulfur content. The RH top powder spraying process has the following defects: (1) The utilization rate of the desulfurization powder is low, and a large amount of powder is pumped away under the action of vacuumizing and cannot enter molten steel to be effectively utilized; (2) The vacuum system equipment is affected by the powder agent, is easy to wear and reduces the working efficiency; (3) The top powder gun is easy to burn, the powder yield is too low due to too high gun position, and the splashed molten steel is easy to burn due to too low gun position; (4) The top powder spraying process is not beneficial to dephosphorization, the carrier gas of the process is argon, the oxygen content of the area where the powder is contacted with the molten steel is lower, and thermodynamic conditions for dephosphorization are not provided; (5) The effective utilization rate of the low powder leads to the requirement of a large amount of carrier gas, the temperature drop of the molten steel is greatly increased due to the large amount of carrier gas delivery, and the refining cost is increased.
Patent application number 201811480907.7 discloses a RH refining rotary powder injection dephosphorization method, a top blowing rotary gun is inserted 400-650mm below the liquid level of steel, and carrier gas Ar directly sprays powder into the molten steel, in the method, because the carrier gas is Ar which is not beneficial to dephosphorization, in addition, a spray gun is directly inserted into the liquid level in a vacuum chamber from the top end of the vacuum chamber, the corrosion of the refractory material at the end part of the spray gun is fast, and a top rotating mechanism is easily damaged due to the influence of the powder, so that the environment is polluted by gas leakage. How to realize the high-efficiency refining of pure steel with ultra-low phosphorus content and ultra-low sulfur content at the same time, and the improvement of the quality of molten steel while shortening the refining period becomes a problem to be solved urgently in the steel industry.
Disclosure of Invention
Aiming at the problems, the invention aims to provide an RH powder injection vacuum refining device and a refining method thereof, the refining method shortens the refining period by 1 to 3min compared with the existing RH top powder injection refining method, the end point sulfur content and the phosphorus content can both stably reach below 10ppm, the purity of molten steel is improved, the effective powder yield of the refining method is high, the end point components are stable, the ultra-low-phosphorus and ultra-low-sulfur refining target can be simultaneously achieved, the refining period is short, and the heat loss is less.
The technical scheme of the invention is as follows: the utility model provides a RH powder spray vacuum refining device, includes real empty room, top blowing rifle and ladle, the top blowing rifle inserts real empty room inside top, real empty room bottom is equipped with tedge and downcomer, tedge and downcomer insert respectively in the ladle and with the inside intercommunication of ladle, the real empty room's of tedge one side lower part lateral wall is equipped with the powder gun, the exit end of powder gun is located inside real empty room, the entry end of powder gun is connected with powder gas pipeline, the lower part of tedge is equipped with the lift gas passageway, the exit end of lift gas passageway is located the below of powder gun exit end.
An alloy chute is arranged on the side wall above the vacuum chamber.
The number of the powder spraying guns is 1 to 4.
The lifting gas channel is connected with a gas source valve station.
A RH powder injection vacuum refining method using any one of the RH powder injection vacuum refining devices comprises the following steps:
s1: during refining treatment, the ladle is jacked to the designed position, and the lifting gas in the lifting gas channel is lifted from N 2 Switching to Ar, and carrying the powder spraying carrier gas in the powder spraying gun from N 2 Switching to Ar, measuring the temperature of the molten steel in the ladle, 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, so that molten steel forms circular flow in the vacuum chamber and a steel ladle, measuring temperature and determining oxygen when the vacuum degree of the vacuum chamber reaches 100-10000 Pa, adding a corresponding deoxygenated alloy amount according to the oxygen content of the molten steel, and adding a corresponding alloy amount according to the initial and target difference of alloy elements; (ii) a
S3: after the alloy is added, after the molten steel circulates for 1 to 10min, the powder spraying carrier gas in the powder spraying gun is switched to mixed carrier gas, 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 circularly flows along with the molten steel and participates in metallurgical reaction, the powder spraying is stopped after the powder spraying treatment is carried out for 1 to 12min, and the powder spraying carrier gas in the powder spraying gun is switched to Ar;
s4: carrying out temperature measurement sampling operation on the molten steel, supplementing and adding alloy according to the phosphorus/sulfur content, the content of alloy elements and the temperature of the molten steel, and adjusting the temperature through scrap steel;
s5: the molten steel is circulated to reach the preset time, the blank breaking operation is carried out, the steel ladle descends, the lifting gas in the lifting gas channel and the powder spraying carrier gas in the powder spraying gun are switched to be N with the preset flow 2 And finishing refining.
In the step S3, in the powder blowing process, the carrier gas is oxidizing gas comprising O 2 、CO 2 、Ar、N 2 The powder comprises dephosphorizing synthetic powder and desulfurizing synthetic powder, and the dephosphorizing powder comprises CaO and CaCO 3 One or more of powders, the desulphurised synthesis powder comprising one or more of CaO, caF, mg powders.
In the step S3, the operation of selecting the powder spraying carrier gas in the powder spraying gun is as follows:
when the target steel is ultra-low phosphorus steel, the phosphorus content is less than or equal to 0.005 percent, 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 oxidability of molten steel near the powder is increased, and the powder is dephosphorized by selecting powder for powder spraying;
when the target steel is ultra-low sulfur steel, the sulfur content is less than or equal to 0.002%, ar + CO is selected as the powder spraying carrier gas in the powder spraying gun 2 The mass ratio of the powder to the powder spraying carrier gas is 3 to 40, the circulation flow of the molten steel is increased, the powder is desulfurized, and powder spraying desulfurization operation is carried out;
when the target steel grade needs ultralow phosphorus content and ultralow sulfur content, firstly performing powder injection dephosphorization operation, measuring temperature and determining oxygen after dephosphorization is finished, adding alloy, and then performing powder injection desulfurization operation.
In the steps S2 to S3, the vacuum degree of the vacuum chamber is kept within 100 to 10000Pa.
In the step S3, the total flow of powder spraying carrier gas in the powder spraying gun is 50 to 1000 Nm 3 And h, ensuring that the outlet pressure of a powder gun of the molten steel in the vacuum refining process is more than or equal to 0.2MPa.
And (4) when the molten steel circulates in the step (S3), the outlet of the powder gun is positioned below the molten steel level 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 ascending pipe, the lifting gas channel is arranged at the middle lower part of the ascending pipe, powder can be directly sprayed into molten steel in the RH refining process, the RH refining cycle is shortened by 1 to 3min compared with the existing RH top powder spraying refining cycle, the carrier gas and the powder flow along with the molten steel and have dephosphorization and desulfurization reactions with the molten steel, the phosphorus and the sulfur in the molten steel are reduced to target contents, the powder particles are used as nucleation centers in the process of flowing along with the molten steel, the inclusion, the nitrogen, the hydrogen and other gases in the molten steel are effectively removed, the final sulfur content and the phosphorus content can stably reach below 10ppm, and the purity of the molten steel is improved; 2. when molten steel circulates, the outlet of the powder 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, and meanwhile, mixed carrier gases in different proportions can be used for directly blowing the powder into the molten steel according to the requirements of RH refining target steel grades, so that the powder utilization rate is improved; 3. the invention can realize dephosphorization and desulfurization treatment in the same furnace according to the refining requirements of different target steel grades, improve the purity of the molten steel and reduce the refining cost.
The following will be further described with reference to the accompanying drawings.
Drawings
Fig. 1 is a schematic structural diagram of an RH powder injection vacuum refining apparatus according to an embodiment of the present invention.
Reference numerals are as follows: 1-vacuum chamber, 2-powder gun, 3-ascending tube, 4-lifting gas channel, 5-ladle, 6-molten steel, 7-descending tube, 8-alloy chute and 9-top blowing gun.
Detailed Description
Example 1
As shown in fig. 1, an RH powder injection vacuum refining device includes a vacuum chamber 1, a top blowing gun 9 and a ladle 5, the top blowing gun 9 is inserted into the upper portion inside the vacuum chamber 1, an ascending pipe 3 and a descending pipe 7 are arranged at the bottom of the vacuum chamber 1, the ascending pipe 3 and the descending pipe 7 are respectively inserted into the ladle 5 and are communicated with the inside of the ladle 5, a powder injection gun 2 is arranged on the lower side wall of the vacuum chamber 1 on one side of the ascending pipe 3, the outlet end of the powder injection gun 2 is located inside the vacuum chamber 1, the inlet end of the powder injection gun 2 is connected with a powder gas conveying pipeline, a lifting gas channel 4 is arranged on the lower portion of the ascending pipe 3, and the outlet end of the lifting gas channel 4 is located below the outlet end of the powder injection gun 2.
In the practical use process, the powder gun 2 is arranged on the side wall of the lower part of the vacuum chamber 1 on one side of the ascending pipe 3, the lifting gas channel 4 is arranged on 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 RH refining cycle is shortened by 1 to 3min compared with the existing RH top powder spraying refining cycle, carrier gas and powder flow along with the molten steel and have dephosphorization and desulfurization reactions with 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, inclusions, nitrogen, hydrogen and other gases in the molten steel are effectively removed, the final sulfur content and the phosphorus content can stably 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 arranged on the upper side wall of the vacuum chamber 1.
In the practical 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 the embodiment 1 or the embodiment 2, in the embodiment, the number of the powder guns 2 is 1 to 4.
In the actual use process, the number of the powder guns 2 is 1 to 4, the using number can be determined according to needs when the powder guns are used, and the powder spraying needs in the refining process are guaranteed.
Example 4
Preferably, on the basis of embodiment 1 or embodiment 3, in this embodiment, the lift gas channel 4 is connected with a gas source valve station.
In the practical use process, the lifting gas channel 4 is connected with a gas source valve station, and the gas source valve station can rapidly realize the flow control of the lifting gas in the lifting gas channel.
Example 5
A RH powder injection vacuum refining method using any one of the RH powder injection vacuum refining apparatuses as described in the above embodiments, comprising the steps of:
s1: during refining treatment, the ladle 5 is jacked to the designed position, and the lifting gas in the lifting gas channel 4 is lifted from N 2 Switching to Ar, and carrying the powder spraying carrier gas in the powder spraying gun 2 from N 2 Switching to Ar, measuring the temperature of the molten steel 6 in the steel ladle 5, 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, so that molten steel 6 forms a circulating flow in the vacuum chamber 1 and a steel ladle 5, measuring the temperature and determining the oxygen when the vacuum degree of the vacuum chamber 1 reaches 100-10000 Pa, adding a corresponding deoxygenated alloy amount according to the oxygen content of the molten steel 6, and adding a corresponding alloy amount according to the initial and target difference of alloy elements;
s3: after the alloy is added, after molten steel 6 circulates for 1 to 10min, the powder spraying carrier gas in the powder spraying gun 2 is switched to be mixed carrier gas, 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 circularly flows along with the molten steel 6 and participates in metallurgical reaction, powder spraying is stopped after powder spraying treatment is carried out for 1 to 12min, and the powder spraying carrier gas in the powder spraying gun 2 is switched to be Ar;
s4: carrying out temperature measurement sampling operation on the molten steel 6, supplementing and adding alloy according to the phosphorus/sulfur content, the content of alloy elements and the temperature of the molten steel 6, and adjusting the temperature through scrap steel;
s5: the molten steel 6 circularly reaches the preset time, the blank breaking operation is carried out, the steel ladle 5 descends, the lifting gas in the lifting gas channel 4 and the powder spraying carrier gas in the powder spraying gun 2 are switched to be N with the preset flow 2 And finishing refining.
In the step S3, in the powder blowing process, the carrier gas is oxidizing gas comprising O 2 、CO 2 、Ar、N 2 The powder comprises dephosphorizing synthetic powder and desulfurizing synthetic powder, and the dephosphorizing powder comprises CaO and CaCO 3 One or more of powders, the desulphurised synthesis powder comprising one or more of CaO, caF, mg powders.
In the step S3, the operation of selecting the powder spray carrier gas in the powder spray 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 to 40, the oxidability of molten steel near the powder is increased, the powder is selected from dephosphorization powder, and powder spraying dephosphorization operation is performed;
when the target steel type is ultra-low sulfur steel, ar + CO is selected as the powder spraying carrier gas in the powder spraying gun 2 2 The mass ratio of the powder to the powder spraying carrier gas is 3 to 40, the circulating flow of the molten steel is increased, the powder is selected from desulfurization powder, and powder spraying desulfurization operation is performed;
when the target steel grade needs ultra-low phosphorus content and ultra-low sulfur content, firstly, carrying out powder injection dephosphorization operation, measuring temperature and determining oxygen after dephosphorization is finished, adding alloy, and then, carrying out powder injection desulfurization operation.
According to the invention, aiming at the requirements of RH refining target steel grade, mixed carrier gases with different proportions are used for directly blowing the powder into the molten steel, so that the utilization rate of the powder is improved; and dephosphorization and desulfurization treatment are realized in the same heat, so that the purity of the molten steel is improved, and the refining cost is reduced.
In the steps S2 to S3, the vacuum degree of the vacuum chamber 1 is kept within a range of 100 to 10000Pa.
In the step S3, the total flow of the powder spraying carrier gas in the powder spraying gun 2 is 50 to 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 carrier gas for powder spraying in the powder spraying gun 2 is 100 to 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 production accidents.
And 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 molten steel 6 circulates, the outlet of the powder gun 2 is positioned below the liquid level of the molten steel 6, so that the problems of low powder utilization rate, easy abrasion of vacuum equipment and complex powder spraying equipment are solved.
Example 6
The RH powder injection vacuum refining apparatus is adopted as in example 1, and the RH powder injection vacuum refining method is adopted as in example 5, and the specific process of vacuum refining pure steel by using 300 ton of RH powder injection in this example is as follows:
s1: jacking the steel ladle to a preset position after the steel ladle enters the station, and lifting gas from the flow of 50 to 80Nm 3 N of/h 2 The conversion was carried out at 80 to 120 Nm 3 Ar of/h, the powder injection carrier gas is switched to the flow of 50-80 Nm 3 N of/h 2 The conversion was carried out at 50 to 100Nm 3 Ar of/h, temperature measurement and sampling are carried out;
s2: starting a vacuum pump for vacuumizing, so that molten steel forms circular flow in a vacuum chamber and a steel ladle, wherein the weight of the molten steel is 300 tons, and the components of the incoming molten steel and the components of a target steel grade are shown in a table 1:
TABLE 1 EXAMPLE 6 compositions of molten steel at arrival and target Steel grade
| Item | [C]% | [Mn]% | [S]% | [P]% | [O]% | [N]% |
| Entering a station | 0.035 | 0.050 | 0.0051 | 0.0080 | 0.0750 | 0.0025 |
| Target | 0.005 | 0.205 | 0.0050 | 0.0010 | 0.0011 | 0.0015 |
Measuring the temperature and determining the oxygen when the vacuum degree reaches 100 to 10000Pa, wherein the temperature of molten steel is 1575 ℃, top-gun oxygen blowing operation is carried out according to the temperature oxygen level, the gun position is 3500 to 4000mm, and the oxygen blowing amount is 300 to 350 Nm 3 ；
S3: after the molten steel circulates for 5min, the carrier gas of the powder spraying pipeline is automatically switched to 50 percent of CO 2 +50%O 2 The total flow rate of the carrier gas is 120-150 Nm 3 And h, after carrier gas is stably sprayed into the molten steel from the side surface of the lower end of the vacuum chamber, blowing dephosphorization powder with the particle size of 0.1 to 1mm into the molten steel, enabling the powder to circularly flow along with the molten steel and participate in dephosphorization metallurgical reaction, wherein the powder spraying speed is 140 to 180kg/min, the powder spraying process is stopped after the vacuum degree is kept at 4000 to 6000Pa, the powder spraying is stopped after 10min, and the carrier gas is switched to 50 to 100Nm 3 /h Ar；
S4: adding electrolytic aluminum for deoxidation, measuring the temperature and determining the oxygen after the molten steel circulates for 3min, adding 650-700 kg of electrolytic manganese through an alloy chute, measuring the temperature and determining the oxygen after the molten steel circulates for 3min, and sampling until all components reach the standard;
s5: the molten steel is circulated for 25 min, the air breaking operation is carried out, the steel ladle descends, and the lifting air is switched to 50-80 Nm 3 The nitrogen gas and the carrier gas are switched to 50 to 100Nm 3 N per hour of flow 2 And finishing refining.
Example 7
The RH powder injection vacuum refining apparatus is adopted as in example 1, and the RH powder injection vacuum refining method is adopted as in example 5, and the specific process of vacuum refining pure steel by using 200 tons of RH powder injection in this example is as follows:
s1: jacking the steel ladle to a preset position after the steel ladle enters the station, and lifting gas from the flow of 50 to 80Nm 3 N of/h 2 Switching to 120 to 150Nm 3 Ar of/h, the powder injection carrier gas is switched to the flow of 50-100 Nm 3 N of/h 2 The conversion was carried out at 50 to 100Nm 3 Ar of/h, temperature measurement and sampling are carried out;
s2: starting a vacuum pump for vacuumizing, so that molten steel forms circular flow in the vacuum chamber and a steel ladle, wherein the weight of the molten steel is 200 tons, and the components of the molten steel entering the station and the components of a target steel grade are shown in a table 2:
TABLE 2 example 7 molten steel composition at station and target steel grade composition
| Item | [C]% | [Mn]% | [S]% | [P]% | [O]% | [N]% |
| Entering station | 0.032 | 0.050 | 0.0051 | 0.0080 | 0.0700 | 0.0029 |
| Target | 0.002 | 0.255 | 0.0010 | 0.0100 | 0.0010 | 0.0015 |
Measuring the temperature and determining the oxygen when the vacuum degree reaches 100-10000 Pa, wherein the temperature of the molten steel is 1570 ℃, top lance oxygen blowing operation is carried out according to the temperature oxygen level, the lance position is 3500-4000 mm, and the oxygen blowing amount is 300-350 Nm 3 After the molten steel circulates for 5min, electrolytic aluminum is added for deoxidation, and after the molten steel circulates for 3min, the temperature is measured and the oxygen is determined;
s3: the carrier gas of the powder spraying pipeline is automatically switched to 30 percent CO 2 +70% of Ar and a total flow rate of carrier gas of 120 to 150Nm 3 And h, after carrier gas is stably sprayed into the molten steel from the side surface of the lower end of the vacuum chamber, blowing desulfurization powder with the particle size of 0.1-1mm into the molten steel, enabling the powder to circularly flow along with the molten steel and participate in the desulfurization metallurgical reaction, wherein the powder spraying speed is 150-180 kg/min, the powder spraying process is stopped after the vacuum degree is kept at 4000-6000 Pa, the powder spraying is stopped after 7 min, and the carrier gas is switched to 50-100 Nm 3 Ar of/h;
s4: measuring temperature and determining oxygen, adding 570-600 kg of electrolytic manganese through an alloy chute, circulating the molten steel for 3min, measuring temperature and determining oxygen, and sampling, wherein all components reach the standard;
s5: the molten steel is circulated for 22min, the air breaking operation is carried out, the steel ladle descends, and the lifting air is switched to 50-80 Nm 3 The nitrogen gas and the carrier gas are switched to 50 to 100Nm 3 N per hour of flow 2 And finishing refining.
Example 8
The RH powder injection vacuum refining apparatus is adopted as in example 1, and the RH powder injection vacuum refining method is adopted as in example 5, and the specific process of vacuum refining pure steel by RH powder injection of 150 tons in this example is as follows:
s1: jacking the steel ladle to a preset position after the steel ladle enters the station, and lifting gas from the flow of 50 to 80Nm 3 N of/h 2 The conversion was carried out at 120 to 150Nm 3 Ar of/h, the powder injection carrier gas is switched to the flow rate of 50-100 Nm 3 N of/h 2 Switching to 50 to 100Nm 3 Performing temperature measurement sampling on the Ar of the/h;
s2: starting a vacuum pump for vacuumizing, so that molten steel forms circular flow in a vacuum chamber and a steel ladle, wherein the weight of the molten steel is 150 tons, and the components of the incoming molten steel and the components of a target steel grade are shown in a table 3:
TABLE 3 example 8 compositions of molten steel entering station and target steel grade
| Item | [C]% | [Mn]% | [S]% | [P]% | [O]% | [N]% |
| Entering station | 0.032 | 0.050 | 0.0051 | 0.0080 | 0.0700 | 0.0029 |
| Target | 0.002 | 0.255 | 0.0010 | 0.0010 | 0.0010 | 0.0015 |
When the vacuum degree reaches 100-10000 Pa, measuring the temperature and determining the oxygen, wherein the temperature of the molten steel is 1580 ℃, and top gun oxygen blowing operation is carried out according to the temperature oxygen level, wherein the gun level is 4000-5000 mm, and the oxygen blowing amount is 200-250 Nm 3 ；
S3: firstly, powder spraying dephosphorization is carried out, when the molten steel circulates for 5min, the carrier gas of the powder spraying pipeline is automatically switched to 60 percent CO 2 +40%O 2 The total flow rate of the carrier gas is 120-150 Nm 3 H, after the carrier gas is stably sprayed into the molten steel from the side surface of the lower end of the vacuum chamber, the dephosphorizing powder with the particle size of 0.1-1mm is blown into the molten steel, and the powder is mixed with the molten steelMolten steel circularly flows to participate in dephosphorization metallurgical reaction, the powder spraying speed is 150 to 180kg/min, the powder spraying process is carried out, the vacuum degree is kept at 3000 to 6000Pa, the powder spraying is stopped after 8 min, and the carrier gas is switched to 50 to 80Nm 3 Ar is calculated by the formula; and after circulating for 2min, adding 200 kg of electrolytic aluminum for deoxidation, and after circulating the molten steel for 2min, measuring the temperature and determining the oxygen. The carrier gas of the powder spraying pipeline is automatically switched to the flow rate of 120 to 150Nm 3 Ar of/h, after carrier gas is stably sprayed into the molten steel from the side surface of the lower end of the vacuum chamber, blowing desulfurization powder with the particle size of 0.1-1mm into the molten steel, enabling the powder to circularly flow along with the molten steel and participate in desulfurization metallurgical reaction, wherein the powder spraying speed is 140-160 kg/min, the powder spraying process is stopped after the vacuum degree is kept at 3000-6000 Pa, the powder spraying is stopped after 9 min, and the carrier gas is switched to 50-100 Nm 3 Ar of/h;
s4: measuring temperature and determining oxygen, adding 430 kg of electrolytic manganese through an alloy chute, circulating the molten steel for 3min, measuring temperature and determining oxygen, and sampling until all components reach the standard;
s5: the molten steel is circulated for 50min, the air breaking operation is carried out, the steel ladle descends, and the lifting air is switched to 50-80 Nm 3 N of/h 2 The carrier gas is switched from 50 to 100Nm 3 N per hour of flow 2 And finishing refining.
The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention.
Claims (10)
1. A RH powder injection vacuum refining device is characterized in that: the powder spraying device is characterized by comprising a vacuum chamber (1), a top blowing gun (9) and a ladle (5), wherein the top blowing gun (9) is inserted into the upper portion inside the vacuum chamber (1), an ascending pipe (3) and a descending pipe (7) are arranged at the bottom of the vacuum chamber (1), the ascending pipe (3) and the descending pipe (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 portion of the vacuum chamber (1) on one side of the ascending pipe (3), the outlet end of the powder spraying gun (2) is located inside the vacuum chamber (1), the inlet end of the powder spraying gun (2) is connected with a powder conveying pipeline, a lifting gas channel (4) is arranged on the lower portion of the ascending pipe (3), and the outlet end of the lifting gas channel (4) is located below the outlet end of the powder spraying gun (2).
2. An RH powder injection vacuum refining device as defined in claim 1, wherein: an alloy chute (8) is arranged on the side wall above the vacuum chamber (1).
3. An RH powder injection vacuum refining device as defined in claim 1, wherein: the number of the powder guns (2) is 1 to 4.
4. An RH powder injection vacuum refining device as defined in claim 1, wherein: the inlet end of the lifting gas channel (4) is connected with a gas source valve station.
5. An RH powder injection vacuum refining method using the RH powder injection vacuum refining device according to any one of claims 1 to 4, characterized in that: the method comprises the following steps:
s1: during refining treatment, the ladle (5) is jacked to the designed position, and the lifting gas in the lifting gas channel (4) is changed from N 2 Switching to Ar, and the powder spraying carrier gas in the powder spraying gun (2) is changed from 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) so that the molten steel (6) forms a circulating flow in the vacuum chamber (1) and the steel ladle (5), measuring the temperature and determining the oxygen when the vacuum degree of the vacuum chamber (1) reaches 100-10000 Pa, adding a corresponding deoxygenated alloy amount according to the oxygen content of the molten steel (6), and adding a corresponding alloy amount according to the initial and target difference of the alloy elements;
s3: after the alloy is added, after the molten steel (6) circulates for 1 to 10min, the carrier gas for powder spraying in the powder spraying gun (2) is switched to mixed carrier gas, 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 circularly flows along with the molten steel (6) and participates in metallurgical reaction, the powder spraying is stopped after the powder spraying treatment is carried out for 1 to 12min, and the carrier gas for powder spraying in the powder spraying gun (2) is switched to Ar;
s4: carrying out temperature measurement sampling operation on the molten steel (6), supplementing and adding alloy according to the phosphorus/sulfur content, the content of alloy elements and the temperature of the molten steel (6), and adjusting the temperature through scrap steel;
s5: the molten steel (6) circularly reaches the preset time to perform the blank breaking operation, the ladle (5) descends, the lifting gas in the lifting gas channel (4) and the powder spraying carrier gas in the powder spraying gun (2) are switched to N with the preset flow 2 And finishing refining.
6. The RH powder injection vacuum refining method as claimed in claim 5, wherein: in the step S3, in the powder blowing process, the carrier gas is oxidizing gas comprising O 2 、CO 2 、Ar、N 2 The powder comprises dephosphorizing synthetic powder and desulfurizing synthetic powder, and the dephosphorizing powder comprises CaO and CaCO 3 One or more of powders, the desulphurised synthesis powder comprising one or more of CaO, caF, mg powders.
7. A RH powder injection vacuum refining method as claimed in claim 5, characterized in that: in the step S3, the operation of selecting the powder spray carrier gas in the powder spray 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 percent, 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 to 40, in order to increase the oxidability of molten steel near the powder, the powder selects dephosphorization powder, and powder spraying dephosphorization operation is performed;
when the target steel grade is ultra-low sulfur steel, the sulfur content is less than or equal to 0.002 percent, and Ar + CO is selected as the powder spraying carrier gas in the powder spraying gun (2) 2 The mass ratio of the powder to the powder spraying carrier gas is 3 to 40, the circulating flow of the molten steel is increased, the powder is selected from desulfurization powder, and powder spraying desulfurization operation is performed;
when the target steel grade needs ultralow phosphorus content and ultralow sulfur content, firstly performing powder injection dephosphorization operation, measuring temperature and determining oxygen after dephosphorization is finished, adding alloy, and then performing powder injection desulfurization operation.
8. A RH powder injection vacuum refining method as claimed in claim 5, characterized in that: in the steps S2 to S3, the vacuum degree of the vacuum chamber (1) is kept at 100 to 10000Pa.
9. The RH powder injection vacuum refining method as claimed in claim 5, wherein: in the step S3, the total flow of the powder spraying carrier gas in the powder spraying gun (2) is 50 to 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.
10. A RH powder injection vacuum refining method as claimed in claim 5, characterized in that: and (4) when the molten steel (6) circulates in the step (S3), 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).
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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 |
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