CN115232920A - Method for improving smelting purity of weathering steel - Google Patents
Method for improving smelting purity of weathering steel Download PDFInfo
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- CN115232920A CN115232920A CN202210894174.1A CN202210894174A CN115232920A CN 115232920 A CN115232920 A CN 115232920A CN 202210894174 A CN202210894174 A CN 202210894174A CN 115232920 A CN115232920 A CN 115232920A
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- 238000000034 method Methods 0.000 title claims abstract description 54
- 238000003723 Smelting Methods 0.000 title claims abstract description 23
- 229910000870 Weathering steel Inorganic materials 0.000 title claims abstract description 21
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 61
- 239000010959 steel Substances 0.000 claims abstract description 61
- 239000011575 calcium Substances 0.000 claims abstract description 48
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 claims abstract description 40
- 229910052791 calcium Inorganic materials 0.000 claims abstract description 40
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 claims abstract description 24
- 238000007670 refining Methods 0.000 claims abstract description 20
- 229910000519 Ferrosilicon Inorganic materials 0.000 claims abstract description 19
- 238000010079 rubber tapping Methods 0.000 claims abstract description 16
- 238000007664 blowing Methods 0.000 claims abstract description 14
- 229910052782 aluminium Inorganic materials 0.000 claims abstract description 12
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims abstract description 12
- 229910052786 argon Inorganic materials 0.000 claims abstract description 12
- 238000005275 alloying Methods 0.000 claims abstract description 10
- 230000003749 cleanliness Effects 0.000 claims abstract description 10
- 238000003756 stirring Methods 0.000 claims abstract description 8
- 229910000720 Silicomanganese Inorganic materials 0.000 claims abstract description 6
- 238000006477 desulfuration reaction Methods 0.000 claims abstract description 6
- 230000023556 desulfurization Effects 0.000 claims abstract description 6
- 238000010438 heat treatment Methods 0.000 claims abstract description 6
- 229910052710 silicon Inorganic materials 0.000 claims abstract description 6
- 238000002360 preparation method Methods 0.000 claims abstract description 5
- 206010039897 Sedation Diseases 0.000 claims abstract description 4
- 230000036280 sedation Effects 0.000 claims abstract description 4
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 20
- 229910000604 Ferrochrome Inorganic materials 0.000 claims description 12
- 229910052799 carbon Inorganic materials 0.000 claims description 12
- 229910052742 iron Inorganic materials 0.000 claims description 10
- 239000000203 mixture Substances 0.000 claims description 5
- 229910052717 sulfur Inorganic materials 0.000 claims description 4
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 claims description 3
- 239000011593 sulfur Substances 0.000 claims description 3
- 230000007613 environmental effect Effects 0.000 abstract 1
- 230000000052 comparative effect Effects 0.000 description 12
- 238000004519 manufacturing process Methods 0.000 description 8
- 238000007254 oxidation reaction Methods 0.000 description 7
- 230000003647 oxidation Effects 0.000 description 6
- 239000000047 product Substances 0.000 description 6
- 229910045601 alloy Inorganic materials 0.000 description 5
- 239000000956 alloy Substances 0.000 description 5
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 5
- 238000009749 continuous casting Methods 0.000 description 5
- 229910052760 oxygen Inorganic materials 0.000 description 5
- 239000001301 oxygen Substances 0.000 description 5
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 4
- 238000005266 casting Methods 0.000 description 3
- 239000005997 Calcium carbide Substances 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 238000005189 flocculation Methods 0.000 description 2
- 230000016615 flocculation Effects 0.000 description 2
- 239000012535 impurity Substances 0.000 description 2
- 238000002844 melting Methods 0.000 description 2
- 230000008018 melting Effects 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 238000005070 sampling Methods 0.000 description 2
- 239000000377 silicon dioxide Substances 0.000 description 2
- 239000000779 smoke Substances 0.000 description 2
- CLZWAWBPWVRRGI-UHFFFAOYSA-N tert-butyl 2-[2-[2-[2-[bis[2-[(2-methylpropan-2-yl)oxy]-2-oxoethyl]amino]-5-bromophenoxy]ethoxy]-4-methyl-n-[2-[(2-methylpropan-2-yl)oxy]-2-oxoethyl]anilino]acetate Chemical compound CC1=CC=C(N(CC(=O)OC(C)(C)C)CC(=O)OC(C)(C)C)C(OCCOC=2C(=CC=C(Br)C=2)N(CC(=O)OC(C)(C)C)CC(=O)OC(C)(C)C)=C1 CLZWAWBPWVRRGI-UHFFFAOYSA-N 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- YLZOPXRUQYQQID-UHFFFAOYSA-N 3-(2,4,6,7-tetrahydrotriazolo[4,5-c]pyridin-5-yl)-1-[4-[2-[[3-(trifluoromethoxy)phenyl]methylamino]pyrimidin-5-yl]piperazin-1-yl]propan-1-one Chemical compound N1N=NC=2CN(CCC=21)CCC(=O)N1CCN(CC1)C=1C=NC(=NC=1)NCC1=CC(=CC=C1)OC(F)(F)F YLZOPXRUQYQQID-UHFFFAOYSA-N 0.000 description 1
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 1
- 229910000655 Killed steel Inorganic materials 0.000 description 1
- WNQQFQRHFNVNSP-UHFFFAOYSA-N [Ca].[Fe] Chemical compound [Ca].[Fe] WNQQFQRHFNVNSP-UHFFFAOYSA-N 0.000 description 1
- 150000004645 aluminates Chemical class 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- JGIATAMCQXIDNZ-UHFFFAOYSA-N calcium sulfide Chemical compound [Ca]=S JGIATAMCQXIDNZ-UHFFFAOYSA-N 0.000 description 1
- XFWJKVMFIVXPKK-UHFFFAOYSA-N calcium;oxido(oxo)alumane Chemical compound [Ca+2].[O-][Al]=O.[O-][Al]=O XFWJKVMFIVXPKK-UHFFFAOYSA-N 0.000 description 1
- OSMSIOKMMFKNIL-UHFFFAOYSA-N calcium;silicon Chemical compound [Ca]=[Si] OSMSIOKMMFKNIL-UHFFFAOYSA-N 0.000 description 1
- 239000008199 coating composition Substances 0.000 description 1
- 239000000571 coke Substances 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000004925 denaturation Methods 0.000 description 1
- 230000036425 denaturation Effects 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 230000005611 electricity Effects 0.000 description 1
- 238000004134 energy conservation Methods 0.000 description 1
- 239000012467 final product Substances 0.000 description 1
- 238000007667 floating Methods 0.000 description 1
- 239000004615 ingredient Substances 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
- 238000005096 rolling process Methods 0.000 description 1
- 239000002893 slag Substances 0.000 description 1
- 238000001179 sorption measurement Methods 0.000 description 1
- 229910052596 spinel Inorganic materials 0.000 description 1
- 239000011029 spinel Substances 0.000 description 1
- 238000009628 steelmaking Methods 0.000 description 1
- 230000007306 turnover Effects 0.000 description 1
Classifications
-
- 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
-
- 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
- C21C5/28—Manufacture of steel in the converter
- C21C5/30—Regulating or controlling the blowing
- C21C5/35—Blowing from above and through the bath
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/0006—Adding metallic additives
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/0056—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00 using cored wires
-
- 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
- C21C7/0075—Treating in a ladle furnace, e.g. up-/reheating of molten steel within the ladle
-
- 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
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Mechanical Engineering (AREA)
- Manufacturing & Machinery (AREA)
- Treatment Of Steel In Its Molten State (AREA)
- Carbon Steel Or Casting Steel Manufacturing (AREA)
Abstract
The invention discloses a method for improving the smelting purity of weathering steel, belonging to the field of steel smelting, wherein in the LF refining step: (1) Si and Mn alloying is not carried out in the converter tapping process; (2) The LF arrival station is added with silicomanganese, ferrosilicon and aluminum according to the components of the argon station; (3) adding Mn to a target value in the slagging process of the refining furnace, and not adding Si; (4) Heating the molten steel to 1590-1600 ℃, adding ferrosilicon 0.5-1 min before the desulfurization and large stirring, and carrying out secondary Si preparation to obtain target components; (5) Argon soft blowing is adopted for the bottom of the steel ladle for sedation, and one-time soft blowing is adopted without calcium feeding treatment of calcium wires. Compared with the prior art, the method can improve the cleanliness of the molten steel, and has the characteristics of environmental protection, cost reduction and efficiency improvement.
Description
Technical Field
The invention relates to a steel smelting process, in particular to a weathering steel smelting technology.
Background
At present, the production process of weathering resistant steel (high Si and low Mn) generally adopts molten iron → an oxygen top and bottom combined blown converter → LF refining → argon soft blowing at the bottom of a steel ladle → calcium treatment → argon soft blowing at the bottom of the steel ladle → thin slab continuous casting and continuous rolling. Wherein the calcium treatment step is a step of converting a high-melting-point spinel inclusion, calcium sulfide, or the like in the aluminum killed steel into a low-melting-point calcium aluminate (12 CaO 7 Al) 2 O 3 、3CaO·Al 2 O 3 ) The problem of water gap blockage is solved. At present, seamless calcium wires, calcium silicon wires and calcium iron wires which are commonly used in the industry are subjected to calcium treatment, and due to the fact that the solubility of Ca in steel is low, part of metal Ca cannot be absorbed by molten steel in the rising process and is gasified to form calcium bubbles. When leaving molten steel, the calcium bubbles have violent oxidation reaction with oxygen in air and oxygen in slag to form splashing to cause secondary oxidation of molten steel, thereby not only polluting the molten steel and destroying the cleanliness of the molten steel, but also generating unfavorable conditions to the field environment.
The control of molten steel cleanliness is always a goal pursued by steelmaking workers because the requirements of the quantity, shape and size of inclusions in steel determine the steel grade and the product application.
The company 'production process of calm clean steel without calcium treatment' (CN 2018100948303) gets rid of the link of calcium treatment process, avoids the problem that high melting point aluminate is easy to flocculate and improves the formability of steel plates, but the technology promotes Al to be soft blown for 20-30min 2 O 3 The inclusions float upward and Al remaining in the molten steel is not removed 2 O 3 The inclusion is denatured, and the flocculation problem in the casting process still exists; and needs to be pretreated by molten iron, and the process route is complicated. In addition, the process cannot be applied to the production of Cr-containing weathering steel and cannot meet the castability requirement of the molten steel of the weathering steel.
Therefore, a new process for controlling secondary oxidation of the molten steel of the weathering steel is urgently needed, and a production process method for reducing molten steel oxidation generated in the conventional calcium treatment process on the premise of stable molten steel quality is required, so that the purposes of improving molten steel cleanliness, protecting environment, controlling, reducing cost and improving efficiency are achieved.
Disclosure of Invention
The technical task of the invention is to provide a method for improving the smelting purity of the weathering steel aiming at the defects of the prior art. The novel process for producing the weathering steel by adopting the alloy calcium treatment cancels the conventional calcium treatment of a calcium line, controls the content of Ca in the molten steel, reduces the oxidation of the molten steel, improves the cleanliness of the molten steel, can cancel the consumption of the calcium line, reduces the production cost, can reduce the overflow of smoke, improves the field environment, can produce stably for a long time, greatly improves the product quality and the application of the client market, and creates greater direct and indirect benefits for companies.
The technical scheme for solving the technical problem is as follows: the method for improving the smelting purity of the weathering steel comprises molten iron → converter smelting → LF refining, and is characterized in that: the LF refining step is controlled as follows:
(1) Si and Mn alloying is not carried out in the converter tapping process;
(2) The LF arrives at the station and is added with silicomanganese according to the composition of the argon station, so that the content of Mn reaches the target internal control lower limit and then is subtracted by 0.02 to 0.07 percent; adding ferrosilicon to make Si content reach 0.15-0.20%; stirring for 2-3min, and feeding aluminum wire for aluminum distribution to make the Als content reach a target value;
(3) In the process of slagging of the refining furnace, mn is added to a target value, and Si is not added;
(4) Heating the molten steel to 1590-1600 ℃, adding ferrosilicon 0.5-1 min before the desulfurization and the stirring are finished, and carrying out secondary Si preparation to the content of the target component;
(5) Argon soft blowing is adopted for the bottom of the steel ladle for sedation, the soft blowing time is more than or equal to 12min, and calcium treatment of calcium feeding lines is not carried out.
In the step of molten iron, the pretreatment of S removal is not needed.
In the smelting step of the converter, the end point temperature of the converter is controlled to be more than or equal to 1620 ℃, and [ O ]:250-450ppm.
In the LF refining step, cr alloying is carried out in the converter tapping process according to the terminal point [ C ].
The Cr alloying is specifically as follows: and if tapping C: 0.09-0.10 percent of high-carbon ferrochrome, and the addition amount of the high-carbon ferrochrome is 2.0-2.5kg per ton of steel; if the tapping C is less than or equal to 0.09 percent, the adding amount of the high-carbon ferrochrome is 3.5 to 4.4kg per ton of steel.
The target component content of Si in the molten steel obtained by LF refining is 0.35-0.45%.
When the Si is prepared for the second time, the internal control value of the sulfur is ensured to be less than or equal to 0.010 percent before the ferrosilicon is added.
Compared with the prior art, the invention has the following outstanding beneficial effects:
1. by the method, a procedure of feeding the calcium wire to the weathering steel is cancelled, the requirements of molten steel cleanliness and castability are effectively improved, floating and adsorption effects of impurities are obvious, and the component percent of pass of the product reaches 100%;
2. the calcium treatment cost is saved, the cost per ton steel is reduced by 4 yuan/t, and the cost is reduced by millions of yuan per year;
3. the method also improves and promotes the aspects of on-site smoke control, customer use and the like.
Detailed Description
The present invention will be further described with reference to the following embodiments.
For the purposes of the following detailed description, it is to be understood that the invention may assume various alternative variations and step sequences, except where expressly specified to the contrary. Moreover, other than in any operating examples, or where otherwise indicated, all numbers expressing, for example, quantities of ingredients used in the specification and claims are to be understood as being modified in all instances by the term "about". At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques.
Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. Any numerical value, however, inherently contains certain errors necessarily resulting from the standard deviation found in their respective testing measurements.
It should also be understood that any numerical range recited herein is intended to include all sub-ranges subsumed therein. For example, a range of "1 to 10" is intended to include all sub-ranges between (and including) the recited minimum value of 1 and the recited maximum value of 10, that is, having a minimum value equal to or greater than 1 and a maximum value of equal to or less than 10.
In this application, the use of the singular includes the plural and plural encompasses singular, unless specifically stated otherwise. In addition, in this application, the use of "or" means "and/or" unless explicitly stated otherwise, even though "and/or" may be explicitly used in some cases. Further, in this application, the use of "a" or "an" means "at least one" unless specifically stated otherwise. For example, "a" first material, "a" coating composition, and the like refer to one or more of any of these items.
The invention provides a method for improving the cleanliness of weathering steel smelting, which adopts a new process of alloy calcium treatment on weathering steel, cancels the procedure of conventional calcium line calcium treatment, reduces the oxidation of molten steel, provides molten steel with higher cleanliness and provides a better product for the weathering steel market.
In order to achieve the purpose, the technical scheme of the invention is as follows: molten iron → converter smelting → LF refining → continuous casting.
S1, molten iron:
no special requirements and no S-removing pretreatment.
S2, smelting in a converter:
the molten iron is primarily smelted in a converter, and the converter is blown by oxygen top and bottom. Controlling the end temperature of the converter to be more than or equal to 1620 ℃, and [ O ]:250-450ppm.
S3, LF refining:
(1) Si and Mn are not alloyed in the converter tapping process, and Cr alloying is only carried out according to the terminal point [ C ]. The method specifically comprises the following steps: and if tapping C: 0.09-0.10 percent of high-carbon ferrochrome, and the addition amount of the high-carbon ferrochrome is 2.0-2.5kg per ton of steel; if the tapping C is less than or equal to 0.09 percent, the adding amount of the high-carbon ferrochrome is 3.5 to 4.4kg per ton of steel.
(2) The LF arrival station adds silicomanganese according to the composition of the argon station, so that the Mn content reaches the target internal control lower limit and then is reduced by 0.02-0.07%; adding ferrosilicon to make Si content reach 0.15-0.20%. Stirring for 2-3min, and feeding aluminum wire to match aluminum to make Als content reach target value.
(3) Mn is added to a target value in the slagging process of the refining furnace, and Si is not added.
(4) Heating the molten steel to 1590-1600 ℃, adding ferrosilicon 0.5-1 min before the desulfurization and the stirring are finished, carrying out secondary Si preparation until the target component (0.35-0.45%), ensuring that the sulfur is removed to an internal control value less than or equal to 0.010% before the ferrosilicon is added, ensuring that the ferrosilicon is completely melted, and sampling and testing the components.
(5) Argon soft blowing is adopted for the bottom of the steel ladle for sedation, the soft blowing time is more than or equal to 12min, and calcium treatment of calcium feeding lines is not carried out.
Obtaining molten steel, and entering a subsequent continuous casting process.
The parts which are not described in the technical scheme are the prior art, and the operation is carried out according to the process and parameters of the prior art.
The invention discloses a secondary Si preparation method: the refining furnace is put to the station to prepare Si for the first time to 0.15-0.20 percent, and the Si is prepared for the second time to 0.35-0.45 percent of the target component after slagging is finished. The ferrosilicon smelting process produces CO through burning coke and reduces SiO in silica at high temperature 2 . Since silica contains associated CaO, ferrosilicon contains a certain amount of metallic Ca. By controlling the adding time and the adding amount, the calcium treatment is realized by utilizing the metal Ca in the alloy, thereby achieving the purpose of the inclusion denaturation. However, in actual production, the content of Ca in each batch is not stable and consistent, and is generally between 1.0% and 2.0%, and the secondary Si-mixing method of the invention not only ensures the alloy melting effect, but also ensures the stability of the Ca in the tundish.
The existing production process of the steel SPA-H is taken as an example, and the mass percent of the molten steel components is controlled as follows: c:0.07 to 0.10 percent of Si: 0.35-0.45%, mn:0.43% -0.53%, P: 0.075-0.100%, S is less than or equal to 0.010%, cr:0.30% -0.36%, cu:0.25% -0.31%, ni:0.05% -0.09%, alt:0.015% -0.050%, and the balance of iron and trace inevitable impurities.
In the LF refining procedure of examples 1-4:
(1) Carrying out Cr alloying in the converter tapping process according to the end point [ C ]; and if tapping C: 0.09-0.10 percent of high-carbon ferrochrome, and the addition amount of the high-carbon ferrochrome is 2.0-2.5kg per ton of steel; if the tapping C is less than or equal to 0.09 percent, the adding amount of the high-carbon ferrochrome is 3.5 to 4.4kg per ton of steel.
(2) The LF arrival station adds silicomanganese to the Mn according to the components of the argon station until the Mn is reduced by 0.05-0.08% to the target inner control lower limit, the embodiment group is 0.038-0.041%, ferrosilicon is added until the Si reaches 0.15-0.20%, the mixture is stirred for 2-3min and then is fed with aluminum wires, and aluminum is added until the Als reaches 0.010-0.020%.
(3) Mn is added to a target value (0.43-0.53%) in the slagging process of the refining furnace.
(4) Heating the molten steel to 1590-1600 ℃, adding ferrosilicon 1min before the desulfurization and large stirring, secondarily preparing Si to 0.35-0.45%, ensuring that S is not more than 0.010% before the ferrosilicon is added, ensuring that the ferrosilicon is completely melted, and sampling and testing components.
Comparative example 1: is an existing process.
(1) In the converter tapping process, mn is added to 0.39-0.41 percent, si is added to 0.28-0.31 percent, and Cr is added to a target value;
(2) And the LF station is matched with silicomanganese, ferrosilicon and other alloys before desulfurization according to the components of the argon station, and the refining station-separating components meet the requirements of steel grades.
(3) Feeding calcium wire for calcium treatment, wherein the usage amount of the calcium wire is 50-60 m/furnace (casting furnace is 70-100 m/furnace), and secondary soft blowing is adopted (the soft blowing time before the calcium treatment is more than or equal to 5min, and the soft blowing time after the calcium treatment is more than or equal to 7 min).
Comparative example 2: the step of pure calcium removal treatment is changed into a step of soft blowing for more than or equal to 12min; the other process step parameters were the same as in comparative example 1.
Other process parameters, examples 1-4 and comparative example were the same.
The Si, mn, alt alloying cases of examples 1 to 4 and comparative example are as follows:
1. the final product steel composition ratios are as follows:
as can be seen from the table above, the molten steels obtained in examples 1 to 4 and comparative example 1 have stable components and meet the product requirements. While Al in comparative example 2 2 O 3 The inclusion is not denatured, becomes flocculent in molten steel, is difficult to float upwards, is easy to gather in a water gap, causes serious flocculent flow in the continuous casting process, and cannot continue production.
By implementing the process of the invention, the molten steel obtained in the groups of examples 1-4 has the same Ca content as the comparative example 1 in which the seamless calcium line is fed for calcium treatment, the castability is good, and no flocculation flow occurs in the casting process of the continuous casting molten steel.
In each example group, the seamless calcium wire feeding is cancelled to carry out calcium treatment, the oxygen content of the tundish is 5-15Ppm lower than that of the comparative example 1 (the prior art), the secondary oxidation of molten steel caused by the overturning and splashing of the molten steel generated in the calcium wire feeding-free process is avoided, and the cleanliness is obviously improved.
2. Comparison of each component
| Aluminum consumption t | Calcium carbide t | Calcium line t | Arrival temperature C | Off-station temperature C | Heating time min | Electricity consumption kwh | |
| Example 1 | 0.128 | 0.075 | 0.000 | 1565.0 | 1583.1 | 12.1 | 3527.7 |
| Example 2 | 0.126 | 0.070 | 0.000 | 1558.0 | 1582.3 | 14.1 | 4227.7 |
| Example 3 | 0.125 | 0.070 | 0.000 | 1560.0 | 1581.5 | 13.1 | 3927.7 |
| Example 4 | 0.112 | 0.072 | 0.000 | 1567.0 | 1580.7 | 12.1 | 3427.7 |
| Comparative example 1 | 0.133 | 0.083 | 0.0229 | 1559.0 | 1581.9 | 16.7 | 4724.5 |
| Comparative example 2 | 0.130 | 0.076 | 0.000 | 1562.0 | 1580.2 | 13.9 | 4027.7 |
The calcium-free wire has no calcium cost, reduces the consumption of calcium carbide and aluminum products, can reduce the temperature drop caused by the turnover of molten steel, and has certain advantages on temperature control, so that the power consumption is lower, and compared with the prior art (comparative example 1), the calcium-free wire has the advantages of low cost, cleanness and energy conservation.
It should be noted that while the invention has been described in detail with respect to specific embodiments thereof, it will be apparent to those skilled in the art that various obvious changes can be made therein without departing from the spirit and scope of the invention.
Claims (7)
1. The method for improving the smelting purity of the weathering steel comprises molten iron → converter smelting → LF refining, and is characterized in that: the LF refining step is controlled as follows:
(1) Si and Mn alloying is not carried out in the converter tapping process;
(2) The LF arrival station adds silicomanganese according to the composition of the argon station, so that the Mn content reaches the target internal control lower limit and then is reduced by 0.02-0.07%; adding ferrosilicon to make Si content reach 0.15-0.20%; stirring for 2-3min, and feeding aluminum wire to match aluminum to make Als content reach target value;
(3) Mn is added to a target value in the slagging process of the refining furnace, and Si is not added;
(4) Heating the molten steel to 1590-1600 ℃, adding ferrosilicon 0.5-1 min before the desulfurization and the stirring are finished, and carrying out secondary Si preparation to the content of the target component;
(5) Argon soft blowing is adopted for the bottom of the steel ladle for sedation, the soft blowing time is more than or equal to 12min, and calcium treatment of calcium feeding lines is not carried out.
2. The method for improving the smelting purity of the weathering steel according to claim 1, characterized in that: in the step of molten iron, S removal pretreatment is not needed.
3. The method for improving the cleanliness of the weathering steel smelting according to claim 1, characterized by: in the smelting step of the converter, the end temperature of the converter is controlled to be more than or equal to 1620 ℃, and [ O ]:250-450ppm.
4. The method for improving the smelting purity of the weathering steel according to claim 1, characterized in that: in the LF refining step, cr alloying is carried out in the converter tapping process according to the terminal point [ C ].
5. The method for improving the smelting purity of the weathering steel according to claim 4, characterized in that: the Cr alloying specifically comprises the following steps: and if tapping C: 0.09-0.10 percent of high-carbon ferrochrome, and the addition amount of the high-carbon ferrochrome is 2.0-2.5kg per ton of steel; if the tapping C is less than or equal to 0.09 percent, the adding amount of the high-carbon ferrochrome is 3.5 to 4.4kg per ton of steel.
6. The method for improving the smelting purity of the weathering steel according to claim 4, characterized in that: the target component content of Si in the molten steel obtained by LF refining is 0.35-0.45%.
7. The method for improving the smelting purity of the weathering steel according to claim 4, characterized in that: when the Si is prepared for the second time, the internal control value of the sulfur is ensured to be less than or equal to 0.010 percent before the ferrosilicon is added.
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| SU1371980A1 (en) * | 1986-02-24 | 1988-02-07 | Центральный научно-исследовательский институт черной металлургии им.И.П.Бардина | Method of treating steel |
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| CN114395658A (en) * | 2022-03-02 | 2022-04-26 | 重庆钢铁股份有限公司 | Low-silicon hot coil Q195 molten steel castability control method |
| CN114472825A (en) * | 2022-02-14 | 2022-05-13 | 日照市质量检验检测研究院 | Continuous casting method for non-calcium treated low-carbon aluminum killed phosphorus-containing steel |
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| SU1371980A1 (en) * | 1986-02-24 | 1988-02-07 | Центральный научно-исследовательский институт черной металлургии им.И.П.Бардина | Method of treating steel |
| CN108330389A (en) * | 2018-01-31 | 2018-07-27 | 日照钢铁控股集团有限公司 | One kind exempting from Calcium treatment calmness clean steel production technology |
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