CN116288018A - Corrosion-resistant hot-rolled wire rod and production method thereof - Google Patents
Corrosion-resistant hot-rolled wire rod and production method thereof Download PDFInfo
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- 230000007797 corrosion Effects 0.000 title claims abstract description 57
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 33
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 86
- 239000010959 steel Substances 0.000 claims abstract description 86
- 238000009749 continuous casting Methods 0.000 claims abstract description 56
- 238000003723 Smelting Methods 0.000 claims abstract description 54
- 238000005096 rolling process Methods 0.000 claims abstract description 51
- 238000000034 method Methods 0.000 claims abstract description 50
- 238000001816 cooling Methods 0.000 claims abstract description 44
- 239000000126 substance Substances 0.000 claims abstract description 40
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- 238000010438 heat treatment Methods 0.000 claims abstract description 19
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- 239000012535 impurity Substances 0.000 claims abstract description 11
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 76
- 238000010079 rubber tapping Methods 0.000 claims description 55
- 230000008569 process Effects 0.000 claims description 46
- PXHVJJICTQNCMI-UHFFFAOYSA-N nickel Substances [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 claims description 43
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 claims description 40
- 239000010949 copper Substances 0.000 claims description 36
- 239000002893 slag Substances 0.000 claims description 34
- 229910052742 iron Inorganic materials 0.000 claims description 33
- 238000007670 refining Methods 0.000 claims description 31
- 239000011572 manganese Substances 0.000 claims description 28
- 238000003756 stirring Methods 0.000 claims description 27
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 21
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- 239000000203 mixture Substances 0.000 claims description 19
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- 238000005275 alloying Methods 0.000 claims description 13
- 229910000859 α-Fe Inorganic materials 0.000 claims description 12
- 238000005266 casting Methods 0.000 claims description 11
- 229910000519 Ferrosilicon Inorganic materials 0.000 claims description 10
- 238000006477 desulfuration reaction Methods 0.000 claims description 10
- 230000023556 desulfurization Effects 0.000 claims description 10
- PYLLWONICXJARP-UHFFFAOYSA-N manganese silicon Chemical compound [Si].[Mn] PYLLWONICXJARP-UHFFFAOYSA-N 0.000 claims description 9
- 238000007664 blowing Methods 0.000 claims description 8
- 239000007788 liquid Substances 0.000 claims description 8
- 238000007711 solidification Methods 0.000 claims description 8
- 230000008023 solidification Effects 0.000 claims description 8
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims description 7
- 229910000604 Ferrochrome Inorganic materials 0.000 claims description 7
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical class [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 claims description 7
- 229910001563 bainite Inorganic materials 0.000 claims description 7
- 239000002131 composite material Substances 0.000 claims description 7
- 229910052802 copper Inorganic materials 0.000 claims description 7
- 229910052759 nickel Inorganic materials 0.000 claims description 7
- 229910001562 pearlite Inorganic materials 0.000 claims description 7
- 230000003009 desulfurizing effect Effects 0.000 claims description 6
- 239000007921 spray Substances 0.000 claims description 6
- 235000008733 Citrus aurantifolia Nutrition 0.000 claims description 4
- 229910001209 Low-carbon steel Inorganic materials 0.000 claims description 4
- 235000011941 Tilia x europaea Nutrition 0.000 claims description 4
- WUKWITHWXAAZEY-UHFFFAOYSA-L calcium difluoride Chemical compound [F-].[F-].[Ca+2] WUKWITHWXAAZEY-UHFFFAOYSA-L 0.000 claims description 4
- 238000009826 distribution Methods 0.000 claims description 4
- 239000010436 fluorite Substances 0.000 claims description 4
- 239000004571 lime Substances 0.000 claims description 4
- 238000007789 sealing Methods 0.000 claims description 4
- 229910000720 Silicomanganese Inorganic materials 0.000 claims description 3
- 239000003595 mist Substances 0.000 claims description 3
- 238000009987 spinning Methods 0.000 claims description 2
- 239000011651 chromium Substances 0.000 description 18
- 238000013461 design Methods 0.000 description 12
- 229910045601 alloy Inorganic materials 0.000 description 9
- 239000000956 alloy Substances 0.000 description 9
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- 238000007599 discharging Methods 0.000 description 2
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- 239000002994 raw material Substances 0.000 description 2
- 229910052710 silicon Inorganic materials 0.000 description 2
- 238000010583 slow cooling Methods 0.000 description 2
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 1
- 238000005452 bending Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000004566 building material Substances 0.000 description 1
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- 229910052729 chemical element Inorganic materials 0.000 description 1
- 229910052804 chromium Inorganic materials 0.000 description 1
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Classifications
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
- B22D11/005—Continuous casting of metals, i.e. casting in indefinite lengths of wire
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
- B22D11/10—Supplying or treating molten metal
- B22D11/11—Treating the molten metal
- B22D11/111—Treating the molten metal by using protecting powders
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
- B22D11/10—Supplying or treating molten metal
- B22D11/11—Treating the molten metal
- B22D11/114—Treating the molten metal by using agitating or vibrating means
- B22D11/115—Treating the molten metal by using agitating or vibrating means by using magnetic fields
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/06—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of rods or wires
- C21D8/065—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of rods or wires of ferrous alloys
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/42—Ferrous alloys, e.g. steel alloys containing chromium with nickel with copper
-
- 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)
- Mechanical Engineering (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Manufacturing & Machinery (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Heat Treatment Of Steel (AREA)
Abstract
The invention discloses a corrosion-resistant hot rolled wire rod and a production method thereof, wherein the wire rod is prepared by adopting the procedures of molten steel smelting, continuous casting, heating, hot continuous rolling and cooling after rolling which are sequentially carried out; the chemical components are as follows: 0.05-0.1% of C, 0.5-1.0% of Si, 0.5-1.0% of Mn, 0.11-0.15% of P, less than or equal to 0.01% of S, 0.2-0.5% of Cr, 0.05-0.1% of Ni, 0.25-0.5% of Cu, and the balance of Fe and unavoidable impurities, and satisfies the following conditions: si/Mn is more than or equal to 0.5 and less than or equal to 1.0,1.2 percent and less than or equal to Si+Cu+Cr+Ni+P is more than or equal to 2 percent, the welding cold crack sensitivity index Pcm is less than or equal to 0.2 percent, the weather resistance index I is more than or equal to 8.0, and the carbon equivalent Ceq is less than or equal to 0.35 percent, thereby solving the problem that the corrosion resistance, welding performance, formability and impact toughness of the hot rolled wire rod are difficult to coordinate and match.
Description
Technical Field
The invention belongs to the technical field of material preparation, and relates to a production method of a corrosion-resistant hot-rolled wire rod and the corrosion-resistant hot-rolled wire rod prepared by the production method.
Background
The hot rolled wire rod is a main building material of ocean engineering, and can be processed into a protective net through processes such as drawing, cold bending, welding and the like, and the protective net plays an extremely important role in the ocean engineering.
Based on the requirement of service environment, the hot rolled wire rod needs to have good marine atmospheric corrosion resistance; from the viewpoint of processing and forming, the hot rolled wire rod is also required to have good machining performance and welding performance; from the viewpoint of island protection safety, the hot rolled wire rod also needs to have high toughness so as to have excellent impact resistance.
However, the hot rolled wire rod in the current market generally adopts to improve the chromium content to improve the corrosion resistance, but the hot rolled wire rod has poorer welding performance and impact toughness, and the alloy cost is higher, so that the production and popularization are not facilitated. Therefore, development of a low-cost hot rolled wire rod with excellent corrosion resistance, welding performance and impact resistance is an urgent technical problem in the field of steel at present, so as to be suitable for ocean engineering.
Disclosure of Invention
The invention aims to provide a corrosion-resistant hot-rolled wire rod and a production method thereof.
In order to achieve the above object, an embodiment of the present invention provides a method for producing a corrosion-resistant hot rolled wire rod, which comprises the steps of molten steel smelting, continuous casting, heating, hot continuous rolling and cooling after rolling, which are sequentially performed to obtain the wire rod; wherein,,
in the molten steel smelting process, the chemical components of molten steel obtained by smelting comprise the following components in percentage by mass: 0.05-0.1% of C, 0.5-1.0% of Si, 0.5-1.0% of Mn, 0.11-0.15% of P, less than or equal to 0.01% of S, 0.2-0.5% of Cr, 0.05-0.1% of Ni, 0.25-0.5% of Cu, and the balance of Fe and unavoidable impurities, and satisfies the following conditions: si/Mn is more than or equal to 0.5 and less than or equal to 1.0,1.2 percent and less than or equal to Si+Cu+Cr+Ni+P is more than or equal to 2 percent, the welding cold crack sensitivity index Pcm is less than or equal to 0.2 percent, the weather resistance index I is more than or equal to 8.0, and the carbon equivalent Ceq is less than or equal to 0.35 percent; wherein,,
Pcm=([C]+[Si]/30+[Mn]/20+[Cu]/20+[Cr]/20+[Ni]/60+[Mo]/15+[V]/10+5[B])×100%；
I=26.01×[Cu]+3.88×[Ni]+1.20×[Cr]+1.49×[Si]+17.28×[P]-7.29×[Cu]×[Ni]-9.1×[Ni]×[P]-33.39×[Cu] 2 ；
Ceq=([C]+[Mn]/6+([Cr]+[Mo]+[V])/5+([Ni]+[Cu])/15)×100%；
in the continuous casting process, casting the molten steel obtained in the molten steel smelting process into a continuous casting blank, wherein low carbon steel covering slag is adopted in the whole casting process, the thickness of a slag layer is 8-10 mm, the continuous casting drawing speed v is constant, and v=2-3 m/min; the water distribution flow rate of the crystallizer is 2000+/-50L/min, the electromagnetic stirring current of the crystallizer is 350A, the stirring frequency is 3-5 Hz, the electromagnetic stirring current of the solidification tail end is 400A, and the stirring frequency is 10-12 Hz; the solidification secondary cooling zone comprises a zone I, a zone II and a zone III, and the water flow rates of the zone I, the zone II and the zone III are respectively: m is m 1 ×v，m 2 ×v，m 3 X v, where m 1 =65L/m，m 2 =75L/m，m 3 =30L/m；
In the heating process, the heating temperature is 1000-1100 ℃;
in the hot continuous rolling process, the heated continuous casting billet is sequentially subjected to three-stage rolling of rough rolling, medium rolling and finish rolling, and rolled into the wire rod, wherein the wire rod spinning temperature is 800-850 ℃;
in the cooling process after rolling, the wire rod is cooled in sections, the first cooling section adopts air cooling or water mist cooling to cool the wire rod to 700 ℃, the cooling speed is more than 3 ℃/s, and the second cooling section slowly cools the wire rod to room temperature, and the cooling speed is less than 2 ℃/s.
Preferably, the molten steel comprises the following chemical components in percentage by mass: 0.05-0.08% of C, 0.6-0.9% of Si, 0.6-0.9% of Mn, 0.11-0.14% of P, less than or equal to 0.01% of S, 0.3-0.4% of Cr, 0.05-0.1% of Ni, 0.3-0.45% of Cu, and the balance of Fe and unavoidable impurities, and satisfies the following conditions: si/Mn is more than or equal to 0.5 and less than or equal to 1.0, si+Cu+Cr+Ni+P is more than or equal to 1 percent and less than or equal to 2 percent, welding cold crack sensitivity index Pcm is less than or equal to 0.2 percent, weather resistance index I is more than or equal to 8.0, and carbon equivalent Ceq is less than or equal to 0.35 percent.
Preferably, the molten steel comprises the following chemical components in percentage by mass: 0.06-0.07% of C, 0.65-0.85% of Si, 0.65-0.85% of Mn, 0.12-0.135% of P, less than or equal to 0.01% of S, 0.3-0.4% of Cr, 0.05-0.1% of Ni, 0.3-0.45% of Cu, and the balance of Fe and unavoidable impurities, and satisfies the following conditions: si/Mn is more than or equal to 0.5 and less than or equal to 1.0, si+Cu+Cr+Ni+P is more than or equal to 1 percent and less than or equal to 2 percent, welding cold crack sensitivity index Pcm is less than or equal to 0.2 percent, weather resistance index I is more than or equal to 8.0, and carbon equivalent Ceq is less than or equal to 0.35 percent.
Preferably, the molten steel smelting process comprises the steps of molten iron desulfurization, primary smelting in a furnace and LF refining which are sequentially carried out;
in the step of desulfurizing molten iron, the temperature of molten iron at a desulfurization end point is more than or equal to 1300 ℃, and S is less than or equal to 0.03%;
in the primary smelting step in the furnace, tapping temperature is 1585-1625 ℃, slag tapping is forbidden during tapping, 6-16 kg/t of silicomanganese and 7-18 kg/t of ferrosilicon are sequentially added into a ladle during tapping to carry out deoxidization alloying, slag is added to carry out slag adjustment, argon is blown during the whole tapping process, and the flow of bottom blowing argon is 200-1000 m from the beginning of tapping to the 3/4 tapping period 3 And/min, wherein the flow of bottom blowing argon after tapping is 200-800 m after 3/4 of tapping 3 /min；
In the LF refining step, after molten steel arrives at a station, argon is blown into the bottom of a ladle, 5-7 kg/T of ferrophosphorus, 4-10 kg/T of low-carbon ferrochrome, 0.5-1 kg/T of nickel plate and 2-5 kg/T of copper block are sequentially added for alloying, lime and fluorite are added into the molten steel for slag adjustment, then electrifying and heating are carried out, after the temperature and chemical components of the molten steel reach the target ranges, a refining covering agent is added into the surface of the molten steel in an LF refining furnace, and quick electrifying is carried out to melt the refining covering agent, then soft stirring is carried out, the soft stirring time is more than or equal to 5 minutes, and the tapping temperature at the LF refining end point is T L +40℃~T L +60 ℃, wherein T L Is the liquidus temperature.
Preferably, the primary smelting step in the furnace adopts electric furnace smelting, desulfurized molten iron and scrap steel are put into the electric furnace for smelting, the total loading amount of the electric furnace is 108-115 t, and the loading amount of the molten iron is more than or equal to 40t; in the tapping process, after the tapping amount reaches 15t, 6-16 kg/t of silicon-manganese and 7-18 kg/t of ferrosilicon are sequentially added into the ladle for deoxidization alloying.
Preferably, the primary smelting step in the furnace adopts converter smelting, desulfurized molten iron and scrap steel are filled into the converter for smelting, the total filling amount of the converter is 49-53 t, and the filling amount of the molten iron is more than or equal to 48t; in the tapping process, after the tapping amount reaches 10t, 6-16 kg/t of silicon-manganese and 7-18 kg/t of ferrosilicon are sequentially added into the ladle for deoxidization alloying.
Preferably, in the continuous casting process, the continuous casting temperature is 1523-1550 ℃, the superheat degree of the tundish is 30 ℃, and the continuous casting process adopts a large ladle of long water gap, a sealing gasket, a submerged nozzle and an alkaline tundish covering agent to carry out full-protection casting, and argon is blown in the long water gap in the whole process.
Preferably, in the continuous casting process, the temperature difference between a water outlet and a water inlet of the crystallizer is less than 10 ℃, the liquid level of the crystallizer is 80%, and the fluctuation of the liquid level of the crystallizer is controlled within +/-7%.
Preferably, in the hot continuous rolling process, the initial rolling temperature of rough rolling is 850-920 ℃, and the initial rolling temperature of finish rolling is 900-960 ℃.
In order to achieve the above object, an embodiment of the present invention further provides a corrosion-resistant hot rolled wire rod manufactured by the above-mentioned method for manufacturing a corrosion-resistant hot rolled wire rod.
As a further improvement of one embodiment, the structure of the wire rod is a multiphase composite structure of ferrite, pearlite and bainite, wherein the proportion of ferrite is 30-45%;
the diameter of the wire rod is 5-16 mm, the yield strength is more than or equal to 370MPa, the tensile strength is more than or equal to 490MPa, the elongation after breaking is more than or equal to 25%, and the impact power KV at 0℃ is higher than or equal to 2 ＞100J；
And in the NaCl salt spray corrosion environment with the temperature of 35 ℃ and the humidity of 70 percent and 3.5 percent, the weightless corrosion rate of the wire rod is 0.125-0.236 g/(m.h).
Compared with the prior art, the invention has the beneficial effects that:
(1) In the aspect of chemical component design, the synergistic effect among the elements is realized through the association relation among the elements, the content and the content of a plurality of elements, specifically, the corrosion resistance and the strengthening effect of the alloy elements such as Si, mn, cr, ni are fully exerted by adopting a low-C and low-S alloy steel component system, so that the corrosion resistance of the hot rolled wire rod can be remarkably improved, the problem that the welding performance, the forming performance and the impact toughness are influenced due to the fact that Cu-P system steel is easily segregated at a crystal boundary can be solved, and the technical problem that the corrosion resistance, the welding performance, the forming performance, the impact toughness and the economy of the Cu-P system steel are difficult to be matched in a synergistic manner is further solved;
(2) Through the optimal design of chemical components, the chemical component design scheme with low welding cold crack sensitivity index and low carbon equivalent is adopted, and the phase change principle is combined, so that the production process is further controlled, the exertion of the strengthening effect of alloy elements and the acquisition of ferrite, pearlite and bainite multiphase composite structures are ensured, the marine environment corrosion resistance of the finally prepared wire rod is improved, the difficult problems that the corrosion resistance, welding performance, formability and impact toughness of the hot rolled wire rod are difficult to coordinate and match are solved, and the raw material cost and the production difficulty are reduced, so that continuous production can be realized by utilizing the existing production line equipment, and the operation is simple and convenient;
(3) The hot rolled wire rod prepared by the production method provided by the invention has a multiphase composite structure of ferrite, pearlite and bainite, wherein the proportion of ferrite is 30-45%; when the diameter of the wire rod is 5-16 mm, the yield strength is more than or equal to 370MPa, the tensile strength is more than or equal to 490MPa, the elongation after breaking is more than or equal to 25%, and the impact power KV at 0℃ is higher than or equal to 2 More than 100J, has excellent mechanical properties; furthermore, in the NaCl salt spray corrosion environment with the temperature of 35 ℃ and the humidity of 70 percent and 3.5 percent, the weightless corrosion rate of the wire rod is 0.125-0.236 g/(m.h), and the marine environment corrosion resistance is greatly improved.
Detailed Description
The technical scheme of the present invention will be further described with reference to the specific embodiments, but the scope of the claims is not limited to the description.
The invention provides a production method of a corrosion-resistant hot-rolled wire rod and the corrosion-resistant hot-rolled wire rod prepared by the production method.
In the production method, molten steel is smelted according to a preset chemical composition design scheme, the obtained molten steel is poured into a continuous casting blank, and then the continuous casting blank is subjected to a heating process, a hot continuous rolling process and a post-rolling cooling process in sequence to prepare the corrosion-resistant hot rolled wire rod.
Specifically, the design scheme of the chemical composition of molten steel obtained by smelting is as follows, namely, the chemical composition of a continuous casting billet cast by molten steel smelting is as follows, namely, the chemical composition of a hot rolled wire rod finally obtained is as follows:
comprises the following components in percentage by mass: 0.05-0.1% of C, 0.5-1.0% of Si, 0.5-1.0% of Mn, 0.11-0.15% of P, less than or equal to 0.01% of S, 0.2-0.5% of Cr, 0.05-0.1% of Ni, 0.25-0.5% of Cu, and the balance of Fe and unavoidable impurities, and satisfies the following conditions: si/Mn is more than or equal to 0.5 and less than or equal to 1.0,1.2 percent and less than or equal to Si+Cu+Cr+Ni+P is more than or equal to 2 percent, the welding cold crack sensitivity index Pcm is less than or equal to 0.2 percent, the weather resistance index I is more than or equal to 8.0, and the carbon equivalent Ceq is less than or equal to 0.35 percent; wherein,,
Pcm=([C]+[Si]/30+[Mn]/20+[Cu]/20+[Cr]/20+[Ni]/60+[Mo]/15+[V]/10+5[B])×100%；
I=26.01×[Cu]+3.88×[Ni]+1.20×[Cr]+1.49×[Si]+17.28×[P]-7.29×[Cu]×[Ni]-9.1×[Ni]×[P]-33.39×[Cu] 2 ；
Ceq=([C]+[Mn]/6+([Cr]+[Mo]+[V])/5+([Ni]+[Cu])/15)×100%。
wherein [ C ] represents a mass percentage value of C, [ Si ] represents a mass percentage value of Si, [ Mn ] represents a mass percentage value of Mn, [ Cu ] represents a mass percentage value of Cu, [ Cr ] represents a mass percentage value of Cr, [ Ni ] represents a mass percentage value of Ni, [ Mo ] represents a mass percentage value of Mo, [ V ] represents a mass percentage value of V, [ B ] represents a mass percentage value of B, [ Si ] represents a mass percentage value of Si, and [ P ] represents a mass percentage value of P. By mass percent, taking C as an example, if the mass percent of C is 0.05%, then the mass percent of C is 0.05, and so on for other chemical components. If the chemical element is not written in the chemical composition, the mass percentage value is calculated as 0, in this embodiment, the mass percentage value [ Mo ] of Mo is calculated as 0, the mass percentage value [ V ] of V is calculated as 0, and the mass percentage value [ B ] of B is calculated as 0.
The chemical composition design scheme realizes the synergistic effect among the elements through the association relation among the elements, the content and the content of the elements. Specifically, by adopting a low-C and low-S alloy steel component system, the corrosion resistance and the strengthening effect of the alloy elements such as Si, mn, cr, ni are fully exerted, so that the corrosion resistance of the hot rolled wire rod can be remarkably improved, the problem that the welding performance, the forming performance and the impact toughness are influenced due to the fact that Cu-P system steel is easy to segregate at a grain boundary can be solved, and the technical problem that the corrosion resistance, the welding performance, the forming performance, the impact toughness and the economy of Cu-P system steel are difficult to cooperatively match is further solved.
Preferably, the molten steel obtained by smelting comprises the following chemical components in percentage by mass: 0.05-0.08% of C, 0.6-0.9% of Si, 0.6-0.9% of Mn, 0.11-0.14% of P, less than or equal to 0.01% of S, 0.3-0.4% of Cr, 0.05-0.1% of Ni, 0.3-0.45% of Cu, and the balance of Fe and unavoidable impurities, and satisfies the following conditions: si/Mn is more than or equal to 0.5 and less than or equal to 1.0, si+Cu+Cr+Ni+P is more than or equal to 1 percent and less than or equal to 2 percent, welding cold crack sensitivity index Pcm is less than or equal to 0.2 percent, weather resistance index I is more than or equal to 8.0, and carbon equivalent Ceq is less than or equal to 0.35 percent. Correspondingly, the chemical composition of the continuous casting billet which is smelted by molten steel and then poured is also described above, and the chemical composition of the finally obtained hot rolled wire rod is also described above. The hot rolled wire rod finally prepared by adopting the chemical composition design scheme has more excellent corrosion resistance, welding performance, forming performance and impact toughness.
More preferably, the molten steel obtained by smelting comprises the following chemical components in percentage by mass: 0.06-0.07% of C, 0.65-0.85% of Si, 0.65-0.85% of Mn, 0.12-0.135% of P, less than or equal to 0.01% of S, 0.3-0.4% of Cr, 0.05-0.1% of Ni, 0.3-0.45% of Cu, and the balance of Fe and unavoidable impurities, and satisfies the following conditions: si/Mn is more than or equal to 0.5 and less than or equal to 1.0, si+Cu+Cr+Ni+P is more than or equal to 1 percent and less than or equal to 2 percent, welding cold crack sensitivity index Pcm is less than or equal to 0.2 percent, weather resistance index I is more than or equal to 8.0, and carbon equivalent Ceq is less than or equal to 0.35 percent. Correspondingly, the chemical composition of the continuous casting billet which is smelted by molten steel and then poured is also described above, and the chemical composition of the finally obtained hot rolled wire rod is also described above. The corrosion resistance, welding performance, forming performance and impact toughness of the hot rolled wire rod finally prepared by adopting the chemical composition design scheme are further optimized.
In terms of process flow, as described above, the production method adopts the procedures of molten steel smelting, continuous casting, heating, hot continuous rolling and cooling after rolling, which are sequentially performed, to prepare the wire rod. The respective steps are described in detail below.
(1) Molten steel smelting process
Comprises the steps of molten iron desulfurization, primary smelting in a furnace and LF refining which are sequentially carried out.
a. Molten iron desulfurization step
Desulfurizing the blast furnace molten iron in a KR desulfurizing device, wherein the temperature of molten iron at the desulfurizing end point is more than or equal to 1300 ℃, and S is less than or equal to 0.03%.
b. Primary refining step in furnace
Firstly, mixing desulfurized molten iron after the molten iron desulfurization step with scrap steel, and dephosphorizing and decarbonizing by adopting an electric furnace or a converter; then tapping, wherein the tapping temperature is 1585-1625 ℃, slag discharging is forbidden during tapping, 6-16 kg/t of silicomanganese and 7-18 kg/t of ferrosilicon are sequentially added into a ladle during tapping to deoxidize and alloy, slag is added into the ladle to adjust slag, argon is blown during the whole tapping process, and the bottom blowing argon flow rate from the tapping beginning to 3/4 tapping is 200-1000 m 3 And/min, wherein the flow of bottom blowing argon after tapping is 200-800 m after 3/4 of tapping 3 /min。
Specifically, when electric furnace smelting is adopted, the desulfurized molten iron and the scrap steel are filled into the electric furnace for smelting, the total filling amount of the electric furnace is 108-115 t, and the filling amount of the molten iron is more than or equal to 40t; in the tapping process, after the tapping amount reaches 15t, 6-16 kg/t of silicon-manganese and 7-18 kg/t of silicon iron are sequentially added into the steel ladle for deoxidization alloying, and then slag is added for slag adjustment. Through electric furnace smelting, after the scrap steel is melted by electrifying and heating, molten iron is added for smelting, and the purity of the molten steel can be improved through high-proportion molten iron.
When the converter is adopted for smelting, the desulfurized molten iron and the scrap steel are filled into the converter for smelting, the total filling amount of the converter is 49-53 t, and the filling amount of the molten iron is more than or equal to 48t; in the tapping process, after the tapping amount reaches 10t, 6-16 kg/t of silicon-manganese and 7-18 kg/t of silicon iron are sequentially added into the steel ladle for deoxidization alloying, and then slag is added for slag adjustment.
Preferably, the scrap steel adopts high-quality scrap steel, namely, the head and tail materials of steel, so that the cleanliness of molten steel can be improved.
LF refining step
Injecting the molten steel obtained in the primary smelting step into an LF refining furnace to adjust the chemical components and the temperature of the molten steel, so that the chemical components and the temperature of the molten steel are quickly adjusted to a target range, specifically, the temperature of the molten steel can be adjusted to the target range by passing through an electric control temperature, sampling and measuring the components of the molten steel obtained in the primary smelting step, and then adding alloy according to the component result to adjust the chemical components of the molten steel to the target range; then, adding a refining covering agent to the surface of molten steel in the LF refining furnace, and rapidly electrifying to melt the refining covering agent, thereby further effectively controlling the content of components in the inclusion; finally, removing the inclusion in the molten steel by soft stirring or vacuum refining.
Specifically, after molten steel arrives at a station, opening ladle bottom argon gas, sequentially adding 5-7 kg/T of ferrophosphorus, 4-10 kg/T of low-carbon ferrochromium, 0.5-1 kg/T of nickel plate and 2-5 kg/T of copper block for alloying, adding lime and fluorite into molten steel according to slag conditions for slag adjustment, then electrifying and heating until the temperature and chemical components of the molten steel reach target ranges, adding a refining covering agent into the surface of the molten steel in an LF refining furnace, rapidly electrifying to melt the refining covering agent, and then carrying out soft stirring, wherein the soft stirring time is more than or equal to 5 minutes, and the tapping temperature at the LF refining end point is T L +40℃~T L +60 ℃, wherein T L Is the liquidus temperature, which can be measured using a high temperature differential scanning calorimeter.
Preferably, the P content in the ferrophosphorus is 23%, the Cr content in the low-carbon ferrochromium is 58%, the Ni content in the nickel plate is 99%, and the Cu content in the copper block is 99%.
(2) Continuous casting process
And pouring the molten steel obtained in the molten steel smelting process into continuous casting equipment to cast a continuous casting blank with the section size of 140mm multiplied by 140 mm. The crystallizer of the continuous casting equipment has an electromagnetic stirring function to perform electromagnetic stirring on the injected molten steel so as to improve the equiaxial crystal proportion of the continuous casting blank. The continuous casting equipment is also provided with an array type withdrawal and straightening machine and a sector section which can realize the function of continuous large reduction, thereby effectively controlling the center porosity and center segregation of the continuous casting blank.
The whole casting process adopts low carbon steel covering slag, the thickness of a slag layer is 8-10 mm, the continuous casting drawing speed v is constant, and v=2-3 m/min; the water distribution flow rate of the crystallizer is 2000+/-50L/min, the electromagnetic stirring current of the crystallizer is 350A, the stirring frequency is 3-5 Hz, the electromagnetic stirring current of the solidification tail end is 400A, and the stirring frequency is 10-12 Hz; the solidification secondary cooling zone comprises a zone I, a zone II and a zone III, and the water flow rates of the zone I, the zone II and the zone III are respectively: m is m 1 ×v，m 2 ×v，m 3 X v, where m 1 =65L/m，m 2 =75L/m，m 3 =30L/m。
Preferably, the continuous casting temperature is 1523-1550 ℃, the superheat degree of the tundish is 30 ℃, and the continuous casting process adopts a large ladle long nozzle, a sealing gasket, a submerged nozzle and an alkaline tundish covering agent to carry out full-protection casting, and argon is blown in the long nozzle in the whole process.
Preferably, the temperature difference between the water outlet and the water inlet of the crystallizer is less than 10 ℃, the liquid level of the crystallizer is 80%, and the fluctuation of the liquid level of the crystallizer is controlled within +/-7%.
And (3) when the continuous casting process is finished, cooling the continuous casting blank to room temperature at 700-800 ℃.
(3) Heating process
And transferring the continuous casting blank into a heating furnace for heating at the temperature of 1000-1100 ℃ so as to realize further homogenization treatment on the continuous casting blank and improve the homogeneity of the continuous casting blank.
(4) Hot continuous rolling process
And sequentially performing rough rolling, intermediate rolling and finish rolling on the heated continuous casting blank to roll the continuous casting blank into the wire rod, and controlling the wire-laying temperature to be 800-850 ℃.
Preferably, the initial rolling temperature of rough rolling is controlled to be 850-920 ℃, and the initial rolling temperature of finish rolling is controlled to be 900-960 ℃.
(5) Post-rolling cooling process
And (3) cooling the wire rod in sections, wherein the first cooling section adopts air cooling or water mist cooling to cool the wire rod to 700 ℃, the cooling speed is more than 3 ℃/s, and the second cooling section adopts slow cooling to cool the wire rod to room temperature, and the cooling speed is less than 2 ℃/s.
Specifically, the first cooling section can adopt a Steyr cooling line to cool the wire rod in an air mode, and the cooling speed is controlled by controlling the roller speed of the Steyr cooling line, the opening quantity, the position and the air quantity of the fans.
Based on the chemical composition design scheme, the management and control of the production process flow are combined, and the structure of the finally prepared hot rolled wire rod is a multiphase composite structure of ferrite, pearlite and bainite, wherein the proportion of ferrite is 30-45%; when the diameter of the wire rod is 5-16 mm, the yield strength is more than or equal to 370MPa, the tensile strength is more than or equal to 490MPa, the elongation after breaking is more than or equal to 25%, and the impact power KV at 0℃ is higher than or equal to 2 More than 100J, has excellent mechanical properties; furthermore, in the NaCl salt spray corrosion environment with the temperature of 35 ℃ and the humidity of 70 percent and 3.5 percent, the weightless corrosion rate of the wire rod is 0.125-0.236 g/(m.h), and the marine environment corrosion resistance is greatly improved.
In summary, the embodiment adopts the chemical component design scheme with low welding cold crack sensitivity index and low carbon equivalent, and combines the phase transformation principle to further control the production process, thereby not only ensuring the exertion of the strengthening effect of alloy elements and the acquisition of ferrite, pearlite and bainite multiphase composite structures, improving the marine environment corrosion resistance of the finally prepared wire rod, solving the difficult problems of difficult coordination and matching of the corrosion resistance, welding performance, formability and impact toughness of the hot rolled wire rod, but also reducing the raw material cost and production difficulty, thereby realizing continuous production by utilizing the equipment of the existing production line, and having simple and convenient operation.
The following provides 5 embodiments (with serial numbers of 1 to 5 respectively) of the present invention to further explain the technical scheme of the present invention. Of course, these 5 examples are only some, but not all of the many variations encompassed by this embodiment.
Specifically, in 5 embodiments, molten steel is smelted according to the following chemical composition design schemes, the obtained molten steel is poured into a continuous casting blank, and the continuous casting blank is prepared into a wire rod according to the production method of the invention.
The chemical composition design scheme is that the chemical composition comprises the following components in percentage by mass: 0.05-0.1% of C, 0.5-1.0% of Si, 0.5-1.0% of Mn, 0.11-0.15% of P, less than or equal to 0.01% of S, 0.2-0.5% of Cr, 0.05-0.1% of Ni, 0.25-0.5% of Cu, and the balance of Fe and unavoidable impurities, and satisfies the following conditions: si/Mn is more than or equal to 0.5 and less than or equal to 1.0,1.2 percent and less than or equal to Si+Cu+Cr+Ni+P is more than or equal to 2 percent, the welding cold crack sensitivity index Pcm is less than or equal to 0.2 percent, the weather resistance index I is more than or equal to 8.0, and the carbon equivalent Ceq is less than or equal to 0.35 percent.
The following describes the specific production method of 5 examples:
(1) Molten steel smelting process
a. Molten iron desulfurization step
The blast furnace molten iron was desulfurized in the KR desulfurization apparatus, and the temperature of the molten iron at the desulfurization end point and the S content in the molten iron are shown in table 1.
b. Primary refining step in furnace
Firstly, mixing the desulfurized molten iron after the molten iron desulfurization step with scrap steel for smelting, wherein the smelting mode can adopt electric furnace smelting or converter smelting, and the concrete smelting mode and the loading amount of the molten iron are shown in table 1; tapping after dephosphorization and decarburization, during tapping, slag discharging is forbidden, in the tapping process, ferrosilicon and ferrosilicon are sequentially added into a ladle for deoxidization alloying, slag charge is added for slag adjustment, argon is blown in the whole tapping process, and the bottom blowing argon flow rate from the tapping beginning to 3/4 of tapping is 200-1000 m 3 And/min, wherein the flow of bottom blowing argon after tapping is 200-800 m after 3/4 of tapping 3 And/min. The tapping temperature, the addition amount of silicon manganese and the addition amount of ferrosilicon are shown in table 1.
If electric furnace smelting is adopted, after the tapping amount reaches 15t, sequentially adding silicon-manganese and silicon-iron into a ladle to deoxidize and alloy, and then adding slag to adjust slag. If converter smelting is adopted, after the tapping amount reaches 10t, sequentially adding silicon-manganese and silicon-iron into a ladle to deoxidize and alloy, and then adding slag to adjust slag.
TABLE 1
LF refining step
Injecting molten steel obtained in the primary smelting step into an LF refining furnace, starting a ladle to blow argon after the ladle arrives at the station, sequentially adding ferrophosphorus, low-carbon ferrochromium, a nickel plate and copper blocks for alloying, adding lime and fluorite into the molten steel according to slag conditions for slag adjustment, electrifying and heating, adding a refining covering agent to the surface of the molten steel in the LF refining furnace after the temperature and chemical components of the molten steel reach target ranges, quickly electrifying to melt the refining covering agent, and then carrying out soft stirring for more than or equal to 5 minutes, wherein the tapping temperature at the end point of LF refining is T L +40℃~T L +60 ℃, wherein T L The liquidus temperature, in this example, the addition amount of ferrophosphorus, low carbon ferrochromium, nickel plate and copper block, tapping temperature, and soft stirring time are shown in Table 2.
Wherein the P content in the ferrophosphorus is 23%, the Cr content in the low-carbon ferrochromium is 58%, the Ni content in the nickel plate is 99%, and the Cu content in the copper block is 99%.
TABLE 2
The molten steel obtained in the molten steel smelting step was sampled and the components were measured, and the results of the sampling and detection of the chemical components of the molten steel of 5 examples in mass percent are shown in table 3.
TABLE 3 Table 3
(2) Continuous casting process
The molten steel obtained in the molten steel smelting process was poured into a continuous casting apparatus to cast a continuous casting billet with a cross-sectional dimension of 140mm×140mm, and the chemical components of the continuous casting billets of 5 examples were sampled and detected in mass percent as shown in table 3.
The continuous casting temperature is 1523-1550 ℃, the superheat degree of the tundish is 30 ℃, the continuous casting process adopts a large ladle long nozzle, a sealing gasket, a submerged nozzle and an alkaline tundish covering agent to carry out full protection casting, and argon is blown in the long nozzle in the whole process; the whole casting process adopts low carbon steel covering slag, the thickness of a slag layer is 8-10 mm, the continuous casting drawing speed v is constant, and the casting drawing speed v is specifically shown in table 4; the water distribution flow of the crystallizer is 2000+/-50L/min, the temperature difference between a water outlet and a water inlet of the crystallizer is less than 10 ℃, the liquid level of the crystallizer is 80%, the fluctuation of the liquid level of the crystallizer is controlled to be within +/-7%, the electromagnetic stirring current of the crystallizer is 350A, the stirring frequency is 3-5 Hz, the electromagnetic stirring current at the solidification tail end is 400A, and the stirring frequency is 10-12 Hz; the water flows of the first, second and third sections of the solidification secondary cooling zone are shown in Table 4.
And (3) when the continuous casting process is finished, cooling the continuous casting blank to room temperature at 700-800 ℃.
TABLE 4 Table 4
(3) Heating process
The continuous casting slab was transferred into a heating furnace and heated at the temperature shown in table 5.
(4) Hot continuous rolling process
The heated continuous casting billet is sequentially subjected to three-stage rolling of rough rolling, medium rolling and finish rolling to roll the continuous casting billet into a wire rod, the diameter of the wire rod is shown in table 5, and the chemical compositions of the wire rods of 5 examples are shown in table 3 in percentage by mass through sampling detection. The initial rolling temperature, the initial rolling temperature of the finish rolling, and the wire feeding temperature of the rough rolling are shown in Table 5.
(5) Post-rolling cooling process
The wire rod is cooled in a sectional mode, the wire rod is cooled to 700 ℃ by adopting a stelmor cooling line in a first cooling section, the wire rod is cooled to room temperature by adopting slow cooling in a second cooling section, and the cooling speeds of the first cooling section and the second cooling section are respectively shown in table 5.
TABLE 5
The microstructure of the obtained wire rods was observed by an optical microscope, and the metallographic structure results of the wire rods of 5 examples are shown in Table 6.
In terms of mechanical properties, referring to standard test methods and definitions of ASTM A370 steel product mechanical property tests, a tensile testing machine is adopted to test the yield strength, the tensile strength and the elongation after break of the wire rods of 5 embodiments; referring to GB/T229 Charpy pendulum impact test method for Metal Material, the pendulum impact tester manufactured by Inst Lang Co., U.S.A. was used to test the impact energy of the wire rods of 5 examples, the test temperature was 0 ℃, and the test sample specification: the width, the height and the length are 10mm, 10mm and 55mm, and the notch is V-shaped; the results of measuring the mechanical properties of 5 examples are shown in Table 6.
In terms of corrosion resistance, a wire rod sample with a length of 100mm was cut, and a salt spray corrosion test was performed by placing the wire rod sample in a 3.5% NaCl solution with a pH value of 7.0 at 35℃and a humidity of 70%, for 14 days, and the weight of the wire rod sample before and after corrosion was measured by using an electron microbalance, and the weight loss corrosion rates of the wire rods of 5 examples were measured as shown in Table 6.
TABLE 6
As can be seen from table 6, the wire rods of examples 1 to 5 all have a multiphase composite structure of ferrite, pearlite and bainite, wherein the ratio of ferrite is 30 to 45%; when the diameter of the wire rod is 5-16 mm, the yield strength is more than or equal to 370MPa, the tensile strength is more than or equal to 490MPa, the elongation after breaking is more than or equal to 25%, and the impact power KV at 0℃ is higher than or equal to 2 More than 100J, excellent mechanical properties; under the NaCl salt spray corrosion environment with the temperature of 35 ℃ and the humidity of 70 percent and 3.5 percent, the weightless corrosion rate of the wire rod is 0.125-0.236 g/(m.h), the corrosion resistance is greatly improved, and the wire rod is suitable for ocean engineering with severe service environment.
It should be understood that although the present disclosure describes embodiments, not every embodiment is provided with a separate embodiment, and that this description is for clarity only, and that the skilled artisan should recognize that the embodiments may be combined as appropriate to form other embodiments that will be understood by those skilled in the art.
The above detailed description is merely illustrative of possible embodiments of the present invention, which should not be construed as limiting the scope of the invention, and all equivalent embodiments or modifications that do not depart from the spirit of the invention are intended to be included in the scope of the invention.
Claims (11)
1. The production method of the corrosion-resistant hot rolled wire rod is characterized in that the wire rod is prepared by adopting the procedures of molten steel smelting, continuous casting, heating, hot continuous rolling and cooling after rolling which are sequentially carried out; wherein,,
in the molten steel smelting process, the chemical components of molten steel obtained by smelting comprise the following components in percentage by mass: 0.05-0.1% of C, 0.5-1.0% of Si, 0.5-1.0% of Mn, 0.11-0.15% of P, less than or equal to 0.01% of S, 0.2-0.5% of Cr, 0.05-0.1% of Ni, 0.25-0.5% of Cu, and the balance of Fe and unavoidable impurities, and satisfies the following conditions: si/Mn is more than or equal to 0.5 and less than or equal to 1.0,1.2 percent and less than or equal to Si+Cu+Cr+Ni+P is more than or equal to 2 percent, the welding cold crack sensitivity index Pcm is less than or equal to 0.2 percent, the weather resistance index I is more than or equal to 8.0, and the carbon equivalent Ceq is less than or equal to 0.35 percent; wherein,,
Pcm=([C]+[Si]/30+[Mn]/20+[Cu]/20+[Cr]/20+[Ni]/60+[Mo]/15+[V]/10+5[B])×100%；
I=26.01×[Cu]+3.88×[Ni]+1.20×[Cr]+1.49×[Si]+17.28×[P]-7.29×[Cu]×[Ni]-9.1×[Ni]×[P]-33.39×[Cu] 2 ；
Ceq=([C]+[Mn]/6+([Cr]+[Mo]+[V])/5+([Ni]+[Cu])/15)×100%；
in the continuous casting process, casting the molten steel obtained in the molten steel smelting process into a continuous casting blank, wherein low carbon steel covering slag is adopted in the whole casting process, the thickness of a slag layer is 8-10 mm, the continuous casting drawing speed v is constant, and v=2-3 m/min; the water distribution flow rate of the crystallizer is 2000+/-50L/min, the electromagnetic stirring current of the crystallizer is 350A, the stirring frequency is 3-5 Hz, the electromagnetic stirring current of the solidification tail end is 400A, and the stirring frequency is 10-12 Hz; solidification secondary cooling zoneThe water flow rates of the I area, the II area and the III area are respectively: m is m 1 ×v，m 2 ×v，m 3 X v, where m 1 =65L/m，m 2 =75L/m，m 3 =30L/m；
In the heating process, the heating temperature is 1000-1100 ℃;
in the hot continuous rolling process, the heated continuous casting billet is sequentially subjected to three-stage rolling of rough rolling, medium rolling and finish rolling, and rolled into the wire rod, wherein the wire rod spinning temperature is 800-850 ℃;
in the cooling process after rolling, the wire rod is cooled in sections, the first cooling section adopts air cooling or water mist cooling to cool the wire rod to 700 ℃, the cooling speed is more than 3 ℃/s, and the second cooling section slowly cools the wire rod to room temperature, and the cooling speed is less than 2 ℃/s.
2. The method for producing a corrosion-resistant hot rolled wire rod according to claim 1, wherein the chemical composition of the molten steel comprises, in mass percent: 0.05-0.08% of C, 0.6-0.9% of Si, 0.6-0.9% of Mn, 0.11-0.14% of P, less than or equal to 0.01% of S, 0.3-0.4% of Cr, 0.05-0.1% of Ni, 0.3-0.45% of Cu, and the balance of Fe and unavoidable impurities, and satisfies the following conditions: si/Mn is more than or equal to 0.5 and less than or equal to 1.0, si+Cu+Cr+Ni+P is more than or equal to 1 percent and less than or equal to 2 percent, welding cold crack sensitivity index Pcm is less than or equal to 0.2 percent, weather resistance index I is more than or equal to 8.0, and carbon equivalent Ceq is less than or equal to 0.35 percent.
3. The method for producing a corrosion-resistant hot rolled wire rod according to claim 1, wherein the chemical composition of the molten steel comprises, in mass percent: 0.06-0.07% of C, 0.65-0.85% of Si, 0.65-0.85% of Mn, 0.12-0.135% of P, less than or equal to 0.01% of S, 0.3-0.4% of Cr, 0.05-0.1% of Ni, 0.3-0.45% of Cu, and the balance of Fe and unavoidable impurities, and satisfies the following conditions: si/Mn is more than or equal to 0.5 and less than or equal to 1.0, si+Cu+Cr+Ni+P is more than or equal to 1 percent and less than or equal to 2 percent, welding cold crack sensitivity index Pcm is less than or equal to 0.2 percent, weather resistance index I is more than or equal to 8.0, and carbon equivalent Ceq is less than or equal to 0.35 percent.
4. The method for producing a corrosion-resistant hot rolled wire rod according to any one of claims 1 to 3, wherein the molten steel smelting process comprises the steps of desulfurizing molten iron, primary smelting in a furnace, and LF refining sequentially performed;
in the step of desulfurizing molten iron, the temperature of molten iron at a desulfurization end point is more than or equal to 1300 ℃, and S is less than or equal to 0.03%;
in the primary smelting step in the furnace, tapping temperature is 1585-1625 ℃, slag tapping is forbidden during tapping, 6-16 kg/t of silicomanganese and 7-18 kg/t of ferrosilicon are sequentially added into a ladle during tapping to carry out deoxidization alloying, slag is added to carry out slag adjustment, argon is blown during the whole tapping process, and the flow of bottom blowing argon is 200-1000 m from the beginning of tapping to the 3/4 tapping period 3 And/min, wherein the flow of bottom blowing argon after tapping is 200-800 m after 3/4 of tapping 3 /min；
In the LF refining step, after molten steel arrives at a station, argon is blown into the bottom of a ladle, 5-7 kg/T of ferrophosphorus, 4-10 kg/T of low-carbon ferrochrome, 0.5-1 kg/T of nickel plate and 2-5 kg/T of copper block are sequentially added for alloying, lime and fluorite are added into the molten steel for slag adjustment, then electrifying and heating are carried out, after the temperature and chemical components of the molten steel reach the target ranges, a refining covering agent is added into the surface of the molten steel in an LF refining furnace, and quick electrifying is carried out to melt the refining covering agent, then soft stirring is carried out, the soft stirring time is more than or equal to 5 minutes, and the tapping temperature at the LF refining end point is T L +40℃~T L +60 ℃, wherein T L Is the liquidus temperature.
5. The method for producing corrosion-resistant hot rolled wire rods according to claim 4, wherein the primary smelting step in the furnace adopts electric furnace smelting, desulfurized molten iron and scrap steel are charged into the electric furnace for smelting, the total charging amount of the electric furnace is 108-115 t, and the charging amount of the molten iron is more than or equal to 40t; in the tapping process, after the tapping amount reaches 15t, 6-16 kg/t of silicon-manganese and 7-18 kg/t of ferrosilicon are sequentially added into the ladle for deoxidization alloying.
6. The method for producing corrosion-resistant hot rolled wire rods according to claim 4, wherein the primary smelting step in the furnace adopts converter smelting, desulfurized molten iron and scrap steel are charged into the converter for smelting, the total charging amount of the converter is 49-53 t, and the charging amount of the molten iron is more than or equal to 48t; in the tapping process, after the tapping amount reaches 10t, 6-16 kg/t of silicon-manganese and 7-18 kg/t of ferrosilicon are sequentially added into the ladle for deoxidization alloying.
7. The method for producing corrosion-resistant hot rolled wire rods according to any one of claims 1 to 3, wherein in the continuous casting process, continuous casting temperature is 1523 to 1550 ℃, tundish superheat degree is 30 ℃, and full-protection casting is carried out by adopting a large ladle long nozzle, a sealing gasket, a submerged nozzle and an alkaline tundish covering agent in the continuous casting process, and argon is blown in the long nozzle in the whole process.
8. The method for producing a corrosion-resistant hot rolled wire rod according to any one of claims 1 to 3, wherein in the continuous casting process, the temperature difference between the water outlet and the water inlet of the crystallizer is less than 10 ℃, the liquid level of the crystallizer is 80%, and the fluctuation of the liquid level of the crystallizer is controlled within + -7%.
9. The method for producing a corrosion-resistant hot rolled wire rod according to any one of claims 1 to 3, wherein in the hot continuous rolling step, the initial rolling temperature of rough rolling is 850 to 920 ℃, and the initial rolling temperature of finish rolling is 900 to 960 ℃.
10. A corrosion-resistant hot rolled wire rod, characterized by being produced by the production method of the corrosion-resistant hot rolled wire rod according to any one of claims 1 to 9.
11. The corrosion resistant hot rolled wire rod according to claim 10, wherein the structure of the wire rod is a multiphase composite structure of ferrite + pearlite + bainite, wherein the proportion of ferrite is 30-45%;
the diameter of the wire rod is 5-16 mm, the yield strength is more than or equal to 370MPa, the tensile strength is more than or equal to 490MPa, the elongation after breaking is more than or equal to 25%, and the impact power KV at 0℃ is higher than or equal to 2 ＞100J；
And in the NaCl salt spray corrosion environment with the temperature of 35 ℃ and the humidity of 70 percent and 3.5 percent, the weightless corrosion rate of the wire rod is 0.125-0.236 g/(m.h).
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| CN117248167A (en) * | 2023-11-20 | 2023-12-19 | 江苏省沙钢钢铁研究院有限公司 | Corrosion-resistant I-steel and production method thereof |
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| CN117248167B (en) * | 2023-11-20 | 2024-01-30 | 江苏省沙钢钢铁研究院有限公司 | Corrosion-resistant I-steel and production method thereof |
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