CN114381567A - Production method of super-grade duplex stainless steel for ocean engineering - Google Patents
Production method of super-grade duplex stainless steel for ocean engineering Download PDFInfo
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- 229910001039 duplex stainless steel Inorganic materials 0.000 title claims abstract description 34
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 19
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 142
- 239000010959 steel Substances 0.000 claims abstract description 142
- 238000000034 method Methods 0.000 claims abstract description 84
- 230000008569 process Effects 0.000 claims abstract description 64
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims abstract description 60
- 229910052742 iron Inorganic materials 0.000 claims abstract description 30
- 238000002161 passivation Methods 0.000 claims abstract description 28
- 239000000292 calcium oxide Substances 0.000 claims abstract description 25
- ODINCKMPIJJUCX-UHFFFAOYSA-N calcium oxide Inorganic materials [Ca]=O ODINCKMPIJJUCX-UHFFFAOYSA-N 0.000 claims abstract description 25
- 238000005554 pickling Methods 0.000 claims abstract description 25
- 238000010438 heat treatment Methods 0.000 claims abstract description 22
- 238000005070 sampling Methods 0.000 claims abstract description 21
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims abstract description 20
- 238000006477 desulfuration reaction Methods 0.000 claims abstract description 20
- 230000023556 desulfurization Effects 0.000 claims abstract description 20
- 229910045601 alloy Inorganic materials 0.000 claims abstract description 19
- 239000000956 alloy Substances 0.000 claims abstract description 19
- 238000003723 Smelting Methods 0.000 claims abstract description 16
- 239000002893 slag Substances 0.000 claims abstract description 16
- 238000009529 body temperature measurement Methods 0.000 claims abstract description 15
- BRPQOXSCLDDYGP-UHFFFAOYSA-N calcium oxide Chemical compound [O-2].[Ca+2] BRPQOXSCLDDYGP-UHFFFAOYSA-N 0.000 claims abstract description 15
- 238000005261 decarburization Methods 0.000 claims abstract description 15
- 230000009467 reduction Effects 0.000 claims abstract description 15
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 12
- 238000007670 refining Methods 0.000 claims abstract description 11
- 229910052681 coesite Inorganic materials 0.000 claims abstract description 10
- 229910052906 cristobalite Inorganic materials 0.000 claims abstract description 10
- 239000000377 silicon dioxide Substances 0.000 claims abstract description 10
- 235000012239 silicon dioxide Nutrition 0.000 claims abstract description 10
- 229910052682 stishovite Inorganic materials 0.000 claims abstract description 10
- 229910052905 tridymite Inorganic materials 0.000 claims abstract description 10
- 238000001816 cooling Methods 0.000 claims abstract description 7
- 238000004806 packaging method and process Methods 0.000 claims abstract description 7
- 238000002844 melting Methods 0.000 claims description 20
- 230000008018 melting Effects 0.000 claims description 20
- 238000002156 mixing Methods 0.000 claims description 17
- 238000010079 rubber tapping Methods 0.000 claims description 16
- 239000000243 solution Substances 0.000 claims description 14
- 238000007664 blowing Methods 0.000 claims description 13
- 229910001220 stainless steel Inorganic materials 0.000 claims description 10
- 239000010935 stainless steel Substances 0.000 claims description 10
- WUKWITHWXAAZEY-UHFFFAOYSA-L calcium difluoride Chemical compound [F-].[F-].[Ca+2] WUKWITHWXAAZEY-UHFFFAOYSA-L 0.000 claims description 8
- 239000010436 fluorite Substances 0.000 claims description 8
- 239000000843 powder Substances 0.000 claims description 8
- 239000002184 metal Substances 0.000 claims description 6
- 229910052751 metal Inorganic materials 0.000 claims description 6
- 239000006104 solid solution Substances 0.000 claims description 6
- 238000001035 drying Methods 0.000 claims description 5
- 238000006386 neutralization reaction Methods 0.000 claims description 5
- 238000005259 measurement Methods 0.000 claims description 3
- 238000001514 detection method Methods 0.000 claims 1
- 238000002360 preparation method Methods 0.000 abstract description 4
- 239000002253 acid Substances 0.000 abstract 1
- 230000006872 improvement Effects 0.000 description 7
- 230000007797 corrosion Effects 0.000 description 6
- 238000005260 corrosion Methods 0.000 description 6
- 230000000694 effects Effects 0.000 description 5
- 238000005266 casting Methods 0.000 description 4
- 230000020477 pH reduction Effects 0.000 description 4
- 229910000859 α-Fe Inorganic materials 0.000 description 4
- 229910001566 austenite Inorganic materials 0.000 description 3
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000008092 positive effect Effects 0.000 description 1
- 238000003466 welding Methods 0.000 description 1
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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
- C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
- C21C5/005—Manufacture of stainless steel
-
- 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
- C21C7/0037—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00 by injecting powdered material
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/04—Removing impurities by adding a treating agent
- C21C7/064—Dephosphorising; 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
- C21C7/068—Decarburising
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C33/00—Making ferrous alloys
- C22C33/04—Making ferrous alloys by melting
- C22C33/06—Making ferrous alloys by melting using master alloys
Abstract
The invention relates to the technical field of duplex stainless steel, in particular to a production method of super duplex stainless steel for ocean engineering, which comprises the following steps of S1: molten iron and an alloy solution are introduced into a refining furnace together and mixed to obtain molten steel, and S2: smelting in an AOD furnace, and carrying out decarburization, reduction, dephosphorization and desulfurization, S3: and (2) feeding the obtained billet into a heating furnace, heating to realize solution treatment, and then performing rapid water cooling, wherein the step S4: acid pickling passivation treatment, S5: and (7) packaging and warehousing. According to the invention, in the preparation process of the traditional duplex stainless steel, calcium oxide is added into the AOD furnace, so that the alkaline protection of molten steel can be realized in the smelting process of the molten steel in the AOD furnace, meanwhile, slag skimming and temperature measurement sampling are carried out, the overall condition in the AOD furnace body is determined by measuring the ratio of CaO/SiO2 in the slag, the smooth proceeding of the decarburization, reduction, dephosphorization and desulfurization processes is further ensured, and the overall performance of the duplex stainless steel is further improved.
Description
Technical Field
The invention relates to the technical field of duplex stainless steel, in particular to a production method of super duplex stainless steel for ocean engineering.
Background
The duplex stainless steel is stainless steel with ferrite and austenite accounting for 50 percent respectively, the minimum content of a few phases generally needs to reach 30 percent, the steel has the characteristics of both the austenite and the ferrite stainless steel, compared with the ferrite, the steel has higher plasticity and toughness and no room temperature brittleness, meanwhile, the intergranular corrosion resistance and the welding performance are obviously improved, the 475-DEG C brittleness and the high heat conductivity coefficient of the ferrite stainless steel are maintained, and the steel has the characteristics of superplasticity and the like, compared with the austenite stainless steel, the strength is high, the intergranular corrosion resistance and the chloride stress corrosion resistance are obviously improved, and further the service performance is greatly improved integrally, but in the preparation process of the existing duplex stainless steel, no slag in the whole molten steel refining process is measured, so that in the refining process, the internal condition of a furnace body cannot be accurately judged, and the subsequent tapping process is caused, the quality of steel cannot be strongly guaranteed and needs to be improved.
Disclosure of Invention
The invention aims to solve the defects in the prior art and provides a method for producing super duplex stainless steel for ocean engineering.
In order to achieve the purpose, the invention adopts the following technical scheme: the production method of the super grade duplex stainless steel for ocean engineering comprises the following steps:
s1: firstly, putting an iron blank into a hot-metal ladle for hot melting to obtain molten iron, then melting an alloy, introducing the molten iron and the alloy solution into a refining furnace together for mixing after the alloy is completely melted to obtain molten steel, and tapping the molten steel to a ladle after the mass fraction of the molten steel meets the expected requirement;
s2: secondly, feeding molten steel into an AOD furnace through a steel mixing ladle, smelting by using the AOD furnace, carrying out decarburization, reduction, dephosphorization and desulfurization processes, standing after a series of operation processes are finished, and then pouring to obtain a steel billet;
s3: feeding the obtained steel billet into a heating furnace, heating to realize solid solution treatment, and then carrying out quick water cooling;
s4: carrying out surface pickling passivation treatment on the steel billet, and attaching a layer of passivation film on the surface of the steel billet to obtain finished steel;
s5: and finally, packaging and warehousing the finished steel.
In order to ensure the operation in the subsequent process, the invention has the improvement that in S1, the hot melting temperature of the iron billet is not lower than 1550 ℃, and the temperature of the molten steel in the process of tapping the molten steel out of the ladle is not lower than 1580 ℃.
In order to ensure that the molten steel smoothly enters the AOD furnace, the invention improves that in the S2, the angle is controlled to be 23-25 degrees when the molten steel enters the AOD furnace through a steel mixing ladle.
In order to ensure the smooth proceeding of the subsequent processing process, the improvement of the invention is that in S2, when the molten steel enters the AOD furnace, the temperature is not lower than 1470 ℃, after the molten steel is added into the AOD furnace, a proper amount of calcium oxide is added into the furnace body for alkaline protection.
In order to improve the refining effect of the molten steel, the improvement of the invention is that in S2, after the molten steel enters the AOD furnace through a ladle, slagging-off, temperature measurement and sampling are carried out, the ratio of CaO/SiO2 in the slag is measured, calcium oxide is added into the AOD furnace according to the ratio, and the measurement is carried out for 3-4 times in the whole process.
In order to improve the effectiveness of slag skimming temperature measurement sampling, the invention has the improvement that the temperature should be controlled at 90-100 ℃ in the process of slag skimming temperature measurement sampling.
In order to improve the dephosphorization effect of molten steel, the improvement of the invention is that in the dephosphorization and desulfurization process of S2, a blowing method is adopted for dephosphorization, the blowing time is 30 minutes, then slag skimming and sampling are carried out, the Si content is determined, if the Si content is lower than 0.15%, a dephosphorization period is carried out, and fluorite powder is added for dephosphorization.
In order to improve the effect of the solution treatment on the steel billet, the improvement of the invention is that in S3, the steel billet is preheated by a preheating furnace before being sent into a heating furnace, the heating temperature is 750-800 ℃, and then the steel billet is sent into the heating furnace to be continuously heated to 1250-1260 ℃, and the heating time is 3-4 hours.
In order to ensure the forming effect of the billet, the invention improves that the standing time in the S2 is 10 minutes.
In order to improve the pickling and passivation treatment effect of the stainless steel, the improvement of the invention is that in S4, stainless steel pickling and passivation solution is adopted for pickling and passivation during surface acidification treatment, secondary flowing clear water rinsing is carried out after pickling and passivation is completed, and finally neutralization, rinsing and drying are carried out.
Compared with the prior art, the invention has the advantages and positive effects that:
in the preparation process of the traditional duplex stainless steel, calcium oxide is added into the AOD furnace in the refining stage of the AOD furnace, so that the alkali protection can be realized on the molten steel in the smelting process of the molten steel in the AOD furnace, in addition, the slag skimming and temperature measurement sampling are intermittently performed in the smelting process, the integral condition in the AOD furnace body is determined by measuring the ratio of CaO/SiO2 in the slag, the fine adjustment can be conveniently realized by a worker, the smooth proceeding of the decarburization, the reduction, the dephosphorization and desulfurization processes can be further ensured, the quality of the steel billet after the subsequent tapping is greatly improved, and the integral performance of the duplex stainless steel can be further improved.
Drawings
FIG. 1 is a schematic diagram of the preparation process of the super duplex stainless steel for ocean engineering according to the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
In the description of the present invention, it is to be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like, indicate orientations or positional relationships based on those shown in the drawings, and are used only for convenience in describing the present invention and for simplicity in description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed in a particular orientation, and be operated, and thus, are not to be construed as limiting the present invention. Further, in the description of the present invention, "a plurality" means two or more unless specifically defined otherwise.
Example one
Referring to fig. 1, the present invention provides a technical solution: the production method of the super grade duplex stainless steel for ocean engineering comprises the following steps:
s1: firstly, putting an iron blank into a hot-metal ladle for hot melting to obtain molten iron, then melting an alloy, introducing the molten iron and the alloy solution into a refining furnace together for mixing after the alloy is completely melted to obtain molten steel, and tapping the molten steel to a ladle after the mass fraction of the molten steel meets the expected requirement;
s2: next, molten steel is fed into an AOD furnace through a steel mixing ladle, smelting is carried out by using the AOD furnace, decarburization, reduction, dephosphorization and desulfurization processes are carried out, standing is carried out for 10 minutes after a series of operation processes are finished, and then casting is carried out to obtain a steel billet;
s3: feeding the obtained steel billet into a heating furnace, heating to realize solid solution treatment, and then carrying out quick water cooling;
s4: carrying out surface pickling passivation treatment on the steel billet, and attaching a layer of passivation film on the surface of the steel billet to obtain finished steel;
s5: and finally, packaging and warehousing the finished steel.
The hot melting temperature of the iron billet is not lower than 1550 ℃, the temperature of the molten steel in the process of tapping the steel ladle is not lower than 1580 ℃, and the temperature is not lower than 1580 ℃, so that the rapid melting of the iron billet can be ensured, and the molten iron is formed.
The method comprises the steps that in the process that molten steel enters an AOD furnace through a steel mixing ladle, the angle is controlled to be 23 ℃ during steel mixing, the molten steel can be guaranteed to stably enter the AOD furnace, when the molten steel enters the AOD furnace, the temperature is not lower than 1470 ℃, the temperature in the AOD furnace is kept above 1470 ℃, the molten steel can be prevented from being solidified, after the molten steel enters the AOD furnace, a proper amount of calcium oxide is added into a furnace body for alkaline protection, the calcium oxide is introduced for alkaline protection, and the subsequent processes of decarburization, reduction, dephosphorization desulfurization and the like can be guaranteed to be smoothly carried out.
After molten steel enters the AOD furnace through a charging ladle, slagging-off, temperature measurement and sampling are carried out, the ratio of CaO/SiO2 in the slag is measured, calcium oxide is added into the AOD furnace according to the ratio, 3 is measured in the whole process, the temperature is controlled to be 90 ℃ in the process of slagging-off, temperature measurement and sampling, alkaline protection is realized on the molten steel in the process of smelting the molten steel in the AOD furnace, slagging-off, temperature measurement and sampling are carried out intermittently in the smelting process, the overall condition inside the AOD furnace is determined by measuring the ratio of CaO/SiO2 in the slag, fine adjustment is conveniently realized by a worker, the processes of decarburization, reduction, dephosphorization and desulfurization are ensured to be carried out smoothly, the quality of steel billets after subsequent tapping is greatly improved, and the overall performance of the duplex stainless steel is further improved.
In the dephosphorization and desulfurization process, dephosphorization is carried out by adopting a blowing method, the blowing time is 30 minutes, then slagging-off and sampling are carried out, the Si content is determined, if the Si content is lower than 0.15%, a dephosphorization period is entered, fluorite powder is added into the dephosphorization period, and when dephosphorization is carried out by adopting the blowing method, the speed is high, the efficiency is high, and the fluorite powder is added simultaneously, so that the efficiency of the dephosphorization process can be further improved.
The surface acidification treatment adopts stainless steel pickling passivation solution to carry out pickling passivation, and after the pickling passivation is finished, secondary flowing clear water rinsing is carried out, and finally neutralization, rinsing and drying are carried out, and the pickling passivation process can further improve the corrosion resistance of the duplex stainless steel.
Example two
Referring to fig. 1, the method for producing super duplex stainless steel for ocean engineering includes the following steps:
s1: firstly, putting an iron blank into a hot-metal ladle for hot melting to obtain molten iron, then melting an alloy, introducing the molten iron and the alloy solution into a refining furnace together for mixing after the alloy is completely melted to obtain molten steel, and tapping the molten steel to a ladle after the mass fraction of the molten steel meets the expected requirement;
s2: next, molten steel is fed into an AOD furnace through a steel mixing ladle, smelting is carried out by using the AOD furnace, decarburization, reduction, dephosphorization and desulfurization processes are carried out, standing is carried out for 10 minutes after a series of operation processes are finished, and then casting is carried out to obtain a steel billet;
s3: feeding the obtained steel billet into a heating furnace, heating to realize solid solution treatment, and then carrying out quick water cooling;
s4: carrying out surface pickling passivation treatment on the steel billet, and attaching a layer of passivation film on the surface of the steel billet to obtain finished steel;
s5: and finally, packaging and warehousing the finished steel.
The hot melting temperature of the iron billet is not lower than 1550 ℃, the temperature of the molten steel in the process of tapping the steel ladle is not lower than 1580 ℃, and the temperature is not lower than 1580 ℃, so that the rapid melting of the iron billet can be ensured, and the molten iron is formed.
The method comprises the steps that in the process that molten steel enters an AOD furnace through a steel mixing ladle, the angle is controlled to be 24 ℃ during steel mixing, the molten steel can be guaranteed to stably enter the AOD furnace, when the molten steel enters the AOD furnace, the temperature is not lower than 1470 ℃, the temperature in the AOD furnace is kept above 1470 ℃, the molten steel can be prevented from being solidified, after the molten steel enters the AOD furnace, a proper amount of calcium oxide is added into a furnace body for alkaline protection, the calcium oxide is introduced for alkaline protection, and the subsequent processes of decarburization, reduction, dephosphorization desulfurization and the like can be guaranteed to be smoothly carried out.
After molten steel enters the AOD furnace through a charging ladle, slagging-off, temperature measurement and sampling are carried out, the ratio of CaO/SiO2 in the slag is measured, calcium oxide is added into the AOD furnace according to the ratio, 3 is measured in the whole process, the temperature is controlled to be 95 ℃ in the process of slagging-off, temperature measurement and sampling, alkaline protection is realized on the molten steel in the process of smelting the molten steel in the AOD furnace, slagging-off, temperature measurement and sampling are carried out intermittently in the smelting process, the overall condition inside the AOD furnace body is determined by measuring the ratio of CaO/SiO2 in the slag, fine adjustment is conveniently realized by a worker, the processes of decarburization, reduction, dephosphorization and desulfurization are ensured to be carried out smoothly, the quality of steel billets after subsequent tapping is greatly improved, and the overall performance of the duplex stainless steel is further improved.
In the dephosphorization and desulfurization process, dephosphorization is carried out by adopting a blowing method, the blowing time is 30 minutes, then slagging-off and sampling are carried out, the Si content is determined, if the Si content is lower than 0.15%, a dephosphorization period is entered, fluorite powder is added into the dephosphorization period, and when dephosphorization is carried out by adopting the blowing method, the speed is high, the efficiency is high, and the fluorite powder is added simultaneously, so that the efficiency of the dephosphorization process can be further improved.
The surface acidification treatment adopts stainless steel pickling passivation solution to carry out pickling passivation, and after the pickling passivation is finished, secondary flowing clear water rinsing is carried out, and finally neutralization, rinsing and drying are carried out, and the pickling passivation process can further improve the corrosion resistance of the duplex stainless steel.
EXAMPLE III
Referring to fig. 1, the method for producing super duplex stainless steel for ocean engineering includes the following steps:
s1: firstly, putting an iron blank into a hot-metal ladle for hot melting to obtain molten iron, then melting an alloy, introducing the molten iron and the alloy solution into a refining furnace together for mixing after the alloy is completely melted to obtain molten steel, and tapping the molten steel to a ladle after the mass fraction of the molten steel meets the expected requirement;
s2: next, molten steel is fed into an AOD furnace through a steel mixing ladle, smelting is carried out by using the AOD furnace, decarburization, reduction, dephosphorization and desulfurization processes are carried out, standing is carried out for 10 minutes after a series of operation processes are finished, and then casting is carried out to obtain a steel billet;
s3: feeding the obtained steel billet into a heating furnace, heating to realize solid solution treatment, and then carrying out quick water cooling;
s4: carrying out surface pickling passivation treatment on the steel billet, and attaching a layer of passivation film on the surface of the steel billet to obtain finished steel;
s5: and finally, packaging and warehousing the finished steel.
The hot melting temperature of the iron billet is not lower than 1550 ℃, the temperature of the molten steel in the process of tapping the steel ladle is not lower than 1580 ℃, and the temperature is not lower than 1580 ℃, so that the rapid melting of the iron billet can be ensured, and the molten iron is formed.
The method comprises the steps that in the process that molten steel enters an AOD furnace through a steel mixing ladle, the angle is controlled to be 25 ℃ during steel mixing, the molten steel can be guaranteed to stably enter the AOD furnace, when the molten steel enters the AOD furnace, the temperature is not lower than 1470 ℃, the temperature in the AOD furnace is kept above 1470 ℃, the molten steel can be prevented from being solidified, after the molten steel enters the AOD furnace, a proper amount of calcium oxide is added into a furnace body for alkaline protection, the calcium oxide is introduced for alkaline protection, and the subsequent processes of decarburization, reduction, dephosphorization desulfurization and the like can be guaranteed to be smoothly carried out.
After molten steel enters the AOD furnace through a charging ladle, slagging-off, temperature measurement and sampling are carried out, the ratio of CaO/SiO2 in the slag is measured, calcium oxide is added into the AOD furnace according to the ratio, the measurement is carried out for 4 times in the whole process, the temperature is controlled to be 100 ℃ in the process of slagging-off, temperature measurement and sampling, alkaline protection is realized on the molten steel in the process of smelting the molten steel in the AOD furnace, slagging-off, temperature measurement and sampling are carried out intermittently in the smelting process, the integral condition in the AOD furnace body is determined by measuring the ratio of CaO/SiO2 in the slag, fine adjustment is conveniently realized by a worker, the smooth proceeding of decarburization, reduction, dephosphorization and desulfurization processes is ensured, the quality of steel billets after subsequent tapping is greatly improved, and the integral performance of the duplex stainless steel is further improved.
In the dephosphorization and desulfurization process, dephosphorization is carried out by adopting a blowing method, the blowing time is 30 minutes, then slagging-off and sampling are carried out, the Si content is determined, if the Si content is lower than 0.15%, a dephosphorization period is entered, fluorite powder is added into the dephosphorization period, and when dephosphorization is carried out by adopting the blowing method, the speed is high, the efficiency is high, and the fluorite powder is added simultaneously, so that the efficiency of the dephosphorization process can be further improved.
The surface acidification treatment adopts stainless steel pickling passivation solution to carry out pickling passivation, and after the pickling passivation is finished, secondary flowing clear water rinsing is carried out, and finally neutralization, rinsing and drying are carried out, and the pickling passivation process can further improve the corrosion resistance of the duplex stainless steel.
The working principle is as follows: firstly, putting an iron blank into a hot-metal ladle for hot melting to obtain molten iron, then melting an alloy, after the alloy is completely melted, molten iron and alloy solution are led into a refining furnace together to be mixed to obtain molten steel, and after the mass fraction of the molten steel reaches the expected requirement, tapping steel to a steel ladle, then feeding molten steel into an AOD furnace through a steel ladle, smelting by using the AOD furnace, carrying out decarburization, reduction, dephosphorization and desulfurization processes, standing for 10 minutes after finishing a series of operation processes, then casting to obtain a steel billet, feeding the obtained steel billet into a heating furnace for heating to realize solid solution treatment, then carrying out rapid water cooling, then carrying out surface pickling and passivation treatment on the steel billet, and attaching a layer of passive film on the surface of the steel billet to obtain finished steel, and finally packaging and warehousing the finished steel.
Although the present invention has been described with reference to specific embodiments, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention.
Claims (10)
1. The production method of the super grade duplex stainless steel for ocean engineering is characterized by comprising the following steps:
s1: firstly, putting an iron blank into a hot-metal ladle for hot melting to obtain molten iron, then melting an alloy, introducing the molten iron and the alloy solution into a refining furnace together for mixing after the alloy is completely melted to obtain molten steel, and tapping the molten steel to a ladle after the mass fraction of the molten steel meets the expected requirement;
s2: secondly, feeding molten steel into an AOD furnace through a steel mixing ladle, smelting by using the AOD furnace, carrying out decarburization, reduction, dephosphorization and desulfurization processes, standing after a series of operation processes are finished, and then pouring to obtain a steel billet;
s3: feeding the obtained steel billet into a heating furnace, heating to realize solid solution treatment, then carrying out rapid water cooling, and carrying out performance detection to ensure that all parameters meet requirements;
s4: carrying out surface pickling passivation treatment on the steel billet, and attaching a layer of passivation film on the surface of the steel billet to obtain finished steel;
s5: and finally, packaging and warehousing the finished steel.
2. The method for producing super duplex stainless steel for ocean engineering according to claim 1, wherein the method comprises the following steps: in the step S1, the hot melting temperature of the iron billet is not lower than 1550 ℃, and the temperature of molten steel in the process of tapping the molten steel out of the steel ladle is not lower than 1580 ℃.
3. The method for producing super duplex stainless steel for ocean engineering according to claim 1, wherein the method comprises the following steps: and in the step S2, controlling the angle to be 23-25 degrees when the molten steel is added in the process that the molten steel enters the AOD furnace through the steel adding ladle.
4. The method for producing super duplex stainless steel for ocean engineering according to claim 1, wherein the method comprises the following steps: and in the step S2, when the molten steel enters the AOD furnace, the temperature is not lower than 1470 ℃, and after the molten steel is mixed with the steel ladle and enters the AOD furnace, a proper amount of calcium oxide is added into the furnace body for alkaline protection.
5. The method for producing super duplex stainless steel for ocean engineering according to claim 1, wherein the method comprises the following steps: in S2, after molten steel enters the AOD furnace through a ladle, slagging off, temperature measuring and sampling are carried out, the ratio of CaO/SiO2 in the slag is measured, calcium oxide is added into the AOD furnace according to the ratio, and the measurement is carried out for 3-4 times in the whole process.
6. The method for producing super duplex stainless steel for ocean engineering according to claim 5, wherein the method comprises the following steps: in the process of slagging-off, temperature measurement and sampling, the temperature should be controlled to be 90-100 ℃.
7. The method for producing super duplex stainless steel for ocean engineering according to claim 1, wherein the method comprises the following steps: and in the dephosphorization and desulfurization process in the S2, dephosphorization is carried out by adopting a blowing method, the blowing time is 30 minutes, then slagging-off and sampling are carried out, the Si content is determined, if the Si content is lower than 0.15%, a dephosphorization period is started, and fluorite powder is added for dephosphorization.
8. The method for producing super duplex stainless steel for ocean engineering according to claim 1, wherein the method comprises the following steps: in the S3, the billet steel is preheated by a preheating furnace before being sent into a heating furnace, the heating temperature is 750-800 ℃, and then the billet steel enters the heating furnace to be continuously heated to 1250-1260 ℃, and the heating time is 3-4 hours.
9. The method for producing super duplex stainless steel for ocean engineering according to claim 1, wherein the method comprises the following steps: the standing time in the S2 is 10 minutes.
10. The method for producing super duplex stainless steel for ocean engineering according to claim 1, wherein the method comprises the following steps: in S4, the surface is acidified by using a stainless steel pickling and passivating solution, and after pickling and passivating, secondary flowing clear water rinsing is performed, and finally neutralization, rinsing and drying are performed.
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