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CN115029636B - 450MPa grade high corrosion-resistant coated steel sheet produced by short process and method - Google Patents

450MPa grade high corrosion-resistant coated steel sheet produced by short process and method Download PDF

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CN115029636B
CN115029636B CN202210700581.4A CN202210700581A CN115029636B CN 115029636 B CN115029636 B CN 115029636B CN 202210700581 A CN202210700581 A CN 202210700581A CN 115029636 B CN115029636 B CN 115029636B
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steel
controlling
cooling
strip steel
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CN115029636A (en
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胡宽辉
孟庆格
陈一鸣
孙伟华
张立
周小舟
祝洪川
王俊霖
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Wuhan Iron and Steel Co Ltd
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Wuhan Iron and Steel Co Ltd
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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
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
    • C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
    • C21C7/04—Removing impurities by adding a treating agent
    • C21C7/064—Dephosphorising; Desulfurising
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • 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
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0205—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips of ferrous alloys
    • 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
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0221—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
    • C21D8/0226—Hot rolling
    • 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
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0221—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
    • C21D8/0236—Cold rolling
    • 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
    • C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
    • C21D9/46—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for sheet metals
    • 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
    • C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
    • C21D9/70—Furnaces for ingots, i.e. soaking pits
    • 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
    • C22C38/001—Ferrous alloys, e.g. steel alloys containing N
    • 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
    • C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
    • C23C2/04—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor characterised by the coating material
    • C23C2/06—Zinc or cadmium or alloys based thereon
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
    • C23C2/14—Removing excess of molten coatings; Controlling or regulating the coating thickness
    • C23C2/16—Removing excess of molten coatings; Controlling or regulating the coating thickness using fluids under pressure, e.g. air knives
    • C23C2/18—Removing excess of molten coatings from elongated material
    • C23C2/20—Strips; Plates
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
    • C23C2/26—After-treatment
    • 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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  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
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  • Crystallography & Structural Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Heat Treatment Of Sheet Steel (AREA)

Abstract

A450 MPa grade high corrosion resistant coated steel sheet produced by adopting a short process comprises the following components in percentage by weight: c:0.15 to 0.18 percent, si:0.16 to 0.20 percent, mn:0.40 to 0.60 percent, P is less than or equal to 0.025 percent, S is less than or equal to 0.010 percent, als:0.012 to 0.060 percent, and N is not more than 0.010 percent: the production method comprises the following steps: desulfurizing molten iron; smelting and refining by a conventional electric furnace or converter; continuous casting; descaling in front of a soaking pit; soaking the casting blank; descaling before entering a rolling mill; finish rolling; laminar cooling to coiling temperature and coiling; naturally cooling; cold rolling after conventional pickling; continuous hot dip plating; after packaging, the product is directly sent to a user, or the surface of the strip steel is coated for later use. The mechanical properties of the invention: 450-540 MPa, tensile strength of 510-600 MPa, elongation A not lower than 19%, simple composition, and great significance for social resource conservation, and service performance improvement in industries such as construction, household appliances and the like.

Description

450MPa grade high corrosion-resistant coated steel sheet produced by short process and method
Technical Field
The invention relates to a high-strength high-corrosion-resistance coated steel plate, in particular to a 450 MPa-grade high-strength high-corrosion-resistance coated steel plate with a short process and a production method thereof, wherein the yield strength of the high-strength high-corrosion-resistance coated steel plate is 450-540 MPa, the tensile strength is 510-600 MPa, the elongation is more than or equal to 14%, and the thickness specification of the steel plate is 0.35-0.90 mm.
Background
With the improvement of society, the living standard of people is improved, the industrialization process is continuously developed, natural resources are gradually deficient, and the global requirements for steel products with different application scenes are raised, for example, the industries of building, household appliances, automobiles and the like are provided with severe requirements for the used products, such as green, economy, high performance, high durability and the like.
The prior art and the product adopt low alloy steel with long flow and niobium and titanium, and the process flow is long, and the cost, the energy consumption and the carbon emission are high.
And (3) searching:
the document of Chinese patent publication No. CN105256230 discloses a 450MPa thick-specification hot-dip galvanized steel and a production method thereof. The main components of the composition by weight percent are: c:0.10 to 0.13 percent, si:0 to 0.025 percent, mn:0.8 to 1.2 percent, P:0.008 to 0.016 percent, S:<0.010%, al:0.04 to 0.06 percent, nb: 0.048-0.068%. Sequentially carrying out smelting, casting, hot rolling, pickling cold continuous rolling, hot galvanizing, leveling and withdrawal straightening. It provides a coating with a thickness of 2.5-3.0mm, excellent bending formability, and a coating weight of 275g/m 2 450 MPa-grade thick-gauge hot-dip galvanized steel with uniform surface quality and performance of a thick zinc layer and a production method thereof. The method also adopts a long-flow and niobium-containing component design, and mainly produces products with the thickness of 2.5-3.0mm, and has the advantages of high cost, high emission and poor corrosion resistance.
The document with the Chinese patent publication number of CN109797346A discloses a heat-based flower-free high-strength galvanized sheet for 450 MPa-level light steel construction and a production method thereof. The main components of the composition by weight percent are: c:0.04 to 0.05 percent, si:0.15 to 0.25 percent, mn:1.10 to 1.20 percent, P: less than or equal to 0.015 percent, S: less than or equal to 0.003 percent, als:0.020 to 0.030 percent, ti: 0.010-0.015%, nb: 0.020-0.030%, N is less than or equal to 0.0045%. Sequentially carrying out smelting, casting, hot rolling, acid washing, leveling, hot galvanizing, finishing and withdrawal straightening. The hot-base flower-free pure zinc galvanized plate has a thickness of 1.0-2.0mm. The method shortens the technological process by adopting hot-base acid washing and then galvanization, but the steel contains titanium and niobium alloy elements, so the alloy cost is designed to be higher, and only a 1.0-2.0mm pure zinc coated steel plate can be produced, and the steel plate has high cost, poor corrosion resistance and no production capacity with extremely thin specification.
Disclosure of Invention
The invention aims to overcome the defects of long process flow, high temperature of the process flow, high energy consumption and low corrosion resistance of products in the prior art, and provides the 450 MPa-level high-corrosion-resistance coated steel sheet and the method which ensure that the yield strength of the steel belt is 450MPa, can meet the industrial requirements of buildings, steel structures and the like, and have excellent corrosion resistance and are produced by adopting a short process flow.
Measures for achieving the above object:
a450 MPa grade high corrosion resistant coated steel sheet produced by adopting a short process comprises the following components in percentage by weight: c:0.15 to 0.18 percent, si:0.16 to 0.20 percent, mn:0.40 to 0.60 percent, P is less than or equal to 0.025 percent, S is less than or equal to 0.010 percent, als:0.012 to 0.060, N is not more than 0.010 percent, and the balance is Fe and unavoidable impurities.
Preferably: the weight percentage content of Als is 0.014-0.054%.
A method for producing 450MPa grade high corrosion resistant coated steel sheet by short process comprises the following steps:
1) Desulfurizing molten iron, and controlling S to be less than or equal to 0.002% when the desulfurization is finished;
2) Smelting and refining by a conventional electric furnace or converter;
3) Continuous casting is carried out, the superheat degree of the ladle molten steel is controlled to be 15-35 ℃, the thickness of a casting blank is controlled to be 50-70 mm, and the blank pulling speed is controlled to be 4.5-5.4 m/min;
4) Descaling the casting blank before entering a soaking pit, and controlling the pressure of descaling water to be not lower than 220bar;
5) Soaking the casting blank, and controlling the tapping temperature to be 1160-1180 ℃;
6) High-pressure water descaling before entering a rolling mill, and controlling the pressure of the descaling water to be more than or equal to 260bar;
7) Performing finish rolling, and controlling the thickness of the outlet of the steel plate to be 1.8-4.5 mm after rolling is finished; meanwhile: controlling the reduction rate of the first pass and the second pass to be not lower than 50%; the final rolling temperature is controlled to be 860-880 ℃;
8) Cooling laminar flow to coiling temperature, coiling, and controlling the coiling temperature at 560-580 ℃;
9) Naturally cooling the steel coil to not more than 70 ℃;
10 Cold rolling after conventional acid washing, controlling the cold rolling reduction to be 75-80%, and controlling the thickness of a rolling outlet to be 0.35-0.9 mm;
11 High corrosion resistant coating continuous hot dip coating:
A. firstly heating the strip steel to 640-690 ℃, then heating the strip steel to 770-790 ℃ within 40-60 seconds, and soaking;
B. rapidly cooling to 610-640 ℃ at a cooling speed of 6-15 ℃/s; slowly cooling to 585-605 ℃ at a cooling speed of 2-10 ℃/s;
C. carrying out continuous hot dip plating on the strip steel, and controlling the temperature of the plating solution to be 580-595 ℃;
D. after the galvanization is finished, the galvanized steel is passed through an air knife, the height of the air knife is controlled to be 200-260 mm, the distance between the air knife and the galvanized steel is 4-8 mm, and the pressure of the air knife is 40-80 mbar;
E. cooling, namely cooling the strip steel to not more than 200 ℃ at a cooling speed of 6-10 ℃/s after the air knife is discharged;
F. surface finishing is carried out on the strip steel, and the finishing rolling reduction rate is controlled to be 0.8-1.0%;
12 After continuous hot dip plating, the strip steel is packaged and then directly sent to a user, or the surface of the strip steel is coated;
and (5) coating for later use.
Further: the coating treatment procedure:
cleaning the surface of the strip steel subjected to continuous hot dip plating; then, coating an organic layer or an inorganic coating on the surface of the strip steel twice; and then coating and curing the organic layer or the inorganic coating, and controlling the curing temperature to be 250-310 ℃.
The function and mechanism of each metal element and main process in the invention
C: carbon is a interstitial solid solution element, which has a good effect on the strength improvement of steel. However, too high a carbon content adversely affects the threading weld in the subsequent process. Therefore, the content is limited to a range of 0.15 to 0.18%.
Si: silicon has a strong solid solution strengthening effect and can improve the strength of steel, but high silicon content can deteriorate the performance of hot-dip high corrosion-resistant plating. Therefore, the content is limited to a range of 0.16 to 0.20%.
Mn: manganese has a solid solution strengthening effect and can ensure that the steel has higher strength, so the content of the manganese is limited to be in the range of 0.40-0.60 percent.
Als plays a deoxidizing role in steel, a certain amount of acid-soluble aluminum in the steel is ensured, otherwise, the effect cannot be exerted, but excessive aluminum also can cause aluminum series inclusion in the steel, and particularly for a short-flow production line, the problem of nozzle blockage is extremely easy to occur due to the small nozzle of a continuous casting crystallizer and high aluminum content. Meanwhile, the right amount of aluminum is added into the steel, so that adverse effects of nitrogen and oxygen atoms in the steel on performance can be eliminated. Therefore, the content is limited to a range of 0.012 to 0.060%, and the content of Als is preferably 0.014 to 0.054%.
P: phosphorus is a harmful element in steel, and is easy to cause center segregation of casting blanks. Especially, the sheet casting blank is easy to be biased to grain boundaries in the subsequent hot continuous rolling heating process after segregation, so that the brittleness of steel is obviously increased. Meanwhile, the content of the alloy is controlled below 0.025% based on cost consideration and without affecting the performance of the steel.
S: sulfur is a very harmful element. Sulfur in steel is often present in the form of manganese sulfides, which inclusions deteriorate the toughness of the steel and cause anisotropy of properties, and therefore, it is necessary to control the sulfur content of the steel to be as low as possible. The sulfur content in the steel is controlled below 0.010% based on manufacturing cost considerations.
N: nitrogen is a interstitial solid solution atom which is easily combined with aluminum in steel to form aluminum nitride fine precipitates, which act to refine grains, but a high nitrogen content deteriorates the properties of steel, particularly aging properties. Therefore, the nitrogen content in the steel is controlled below 0.010%.
The invention controls the superheat degree of the ladle molten steel at 15-35 ℃, the thickness of a casting blank at 50-70 mm and the blank drawing speed at 4.5-5.4 m/min, and the problems of surface defects of the casting blank in the continuous casting process, steel leakage in the casting process and the like are caused by high superheat degree of the molten steel or low superheat degree of the molten steel; the thin casting blank thickness and high drawing speed can obtain fine casting blank tissue, and the guarantee is provided for the subsequent tissue of essential fine grain.
The tapping temperature of the casting blank is controlled to be 1160-1180 ℃, and the tapping temperature lower than 1160 ℃ cannot ensure that the steel is rolled in a single-phase austenite region, so that the tapping temperature higher than 1180 ℃ can cause the overhigh temperature of the casting blank, the thickness of the surface oxide scale is increased, and the control of the surface quality is not facilitated.
The invention controls the first and second pass reduction rates to be not less than 50%; the final rolling temperature is 860-880 ℃, and the columnar crystals can be effectively crushed by controlling the rolling reduction of the first pass and the second pass to be not lower than 50%, so that the strip steel can be dynamically or statically recrystallized in the deformation process and after the first pass and before the second pass, and the recrystallization process can be completed. And then controlling the reduction rate to be not lower than 50% in the second pass, crushing a part of austenite after the first pass recrystallization, then recrystallizing to further refine grains, accumulating a large amount of deformation bands in the other part of austenite grains, and increasing nucleation sites in the subsequent phase transformation process.
The coiling temperature of the invention is 560-580 ℃, and the fine hot rolled structure can be obtained by controlling the coiling temperature.
The invention controls the natural cooling of the steel coil to not more than 70 ℃ because of the convenience of subsequent transportation.
The cold rolling reduction rate is controlled to be 75-80%, and the recrystallization structure is obtained at a lower temperature because the cold rolling reduction rate can be matched with the subsequent annealing temperature.
The invention comprises the following steps in the continuous hot dip plating:
A. firstly heating the strip steel to 640-690 ℃, then heating the strip steel to 770-790 ℃ within 40-60 seconds, and soaking;
B. rapidly cooling to 610-640 ℃ at a cooling speed of 6-15 ℃/s; slowly cooling to 585-605 ℃ at a cooling speed of 2-10 ℃/s;
C. carrying out continuous hot dip plating on the strip steel, and controlling the temperature of the plating solution to be 580-595 ℃;
D. after the galvanization is finished, the galvanized steel is passed through an air knife, the height of the air knife is controlled to be 200-260 mm, the distance between the air knife and the galvanized steel is 4-8 mm, and the pressure of the air knife is 40-80 mbar;
E. cooling, namely cooling the strip steel to not more than 200 ℃ at a cooling speed of 6-10 ℃/s after the air knife is discharged;
F. surface finishing is carried out on the strip steel, and the finishing rolling reduction rate is controlled to be 0.8-1.0%; the polishing elongation can ensure that the strip steel obtains a good polishing surface and the plate shape.
Compared with the prior art, the invention ensures that the yield strength of the steel belt is 450-540 MPa, the tensile strength is 510-600 MPa, the elongation A is not lower than 19%, the 1000h neutral salt spray test does not foam, the corrosion phenomenon is avoided, the environment-friendly, economical and high-durability use requirements of industries such as buildings, household appliances and the like can be met, the components are simple, the corrosion resistance is excellent, and the invention has great significance for social resource conservation, and service performance improvement of industries such as buildings, household appliances and the like.
Drawings
FIG. 1 is a metallographic structure diagram of the present invention.
Detailed Description
The present invention will be described in detail below:
table 1 is a listing of chemical components of each example and comparative example of the present invention;
table 2 is a list of the main process parameters for each example and comparative example of the present invention;
table 3 shows a list of performance tests for each example and comparative example of the present invention.
The embodiments of the invention were produced according to the following steps
1) Desulfurizing molten iron, and controlling S to be less than or equal to 0.002% when the desulfurization is finished;
2) Smelting and refining by a conventional electric furnace or converter;
3) Continuous casting is carried out, the superheat degree of the ladle molten steel is controlled to be 15-35 ℃, the thickness of a casting blank is controlled to be 50-70 mm, and the blank drawing speed is controlled to be 4.5 to the ultra-high
5.4m/min；
4) Descaling the casting blank before entering a soaking pit, and controlling the pressure of descaling water to be not lower than 220bar;
5) Soaking the casting blank, and controlling the tapping temperature to be 1160-1180 ℃;
6) High-pressure water descaling before entering a rolling mill, and controlling the pressure of the descaling water to be more than or equal to 260bar;
7) Performing finish rolling, and controlling the thickness of the outlet of the steel plate to be 1.8-4.5 mm after rolling is finished; meanwhile: controlling the reduction rate of the first pass and the second pass to be not lower than 50%; the final rolling temperature is controlled to be 860-880 ℃;
8) Cooling laminar flow to coiling temperature, coiling, and controlling the coiling temperature at 560-580 ℃;
9) Naturally cooling the steel coil to not more than 70 ℃;
10 Cold rolling after conventional acid washing, controlling the cold rolling reduction to be 75-80%, and controlling the thickness of a rolling outlet to be 0.35-0.9 mm;
11 High corrosion resistant coating continuous hot dip coating:
A. firstly heating the strip steel to 640-690 ℃, then heating the strip steel to 770-790 ℃ within 40-60 seconds, and soaking;
B. rapidly cooling to 610-640 ℃ at a cooling speed of 6-15 ℃/s; slowly cooling to 585-605 ℃ at a cooling speed of 2-10 ℃/s;
C. carrying out continuous hot dip plating on the strip steel, and controlling the temperature of the plating solution to be 580-595 ℃;
D. after the galvanization is finished, the galvanized steel is passed through an air knife, the height of the air knife is controlled to be 200-260 mm, the distance between the air knife and the galvanized steel is 4-8 mm, and the pressure of the air knife is 40-80 mbar;
E. cooling, namely cooling the strip steel to not more than 200 ℃ at a cooling speed of 6-10 ℃/s after the air knife is discharged;
F. surface finishing is carried out on the strip steel, and the finishing rolling reduction rate is controlled to be 0.8-1.0%;
12 After continuous hot dip plating, the strip steel is packaged and then directly sent to a user, or the surface of the strip steel is coated; and (5) coating for later use.
Table 1 chemical composition (wt.%) of each example and comparative example of the present invention
Figure BDA0003703829850000071
Table 2 list of values of the main process parameters for each example and comparative example of the present invention
Figure BDA0003703829850000072
Figure BDA0003703829850000081
Continuous table 2
Figure BDA0003703829850000082
TABLE 3 list of mechanical Properties of examples and comparative examples according to the invention
Figure BDA0003703829850000083
Figure BDA0003703829850000091
In conclusion, the invention successfully realizes that the steel has higher strength, good economical efficiency, high durability and other characteristics through the matching design of the low-cost component design, the short-flow process and the hot-dip high corrosion-resistant coating hot-dip process, meets the green, economical and high-durability use requirements of industries such as buildings, household appliances and the like, and has great significance for saving social resources and improving the service performance of industries such as buildings, household appliances and the like.
This embodiment is merely a best example and is not intended to limit the implementation of the technical solution of the present invention.

Claims (2)

1. A method for producing 450MPa grade high corrosion resistant coated steel sheet by short process production comprises the following steps:
1) Desulfurizing molten iron, and controlling S to be less than or equal to 0.002% when the desulfurization is finished;
2) Smelting and refining by a conventional electric furnace or converter;
3) Continuous casting is carried out, the superheat degree of the ladle molten steel is controlled to be 15-35 ℃, the thickness of a casting blank is controlled to be 50-70 mm, and the blank pulling speed is controlled to be 4.5-5.4 m/min;
4) Descaling the casting blank before entering a soaking pit, and controlling the pressure of descaling water to be not lower than 220bar;
5) Soaking the casting blank, and controlling the tapping temperature to be 1160-1180 ℃;
6) High-pressure water descaling before entering a rolling mill, and controlling the pressure of the descaling water to be more than or equal to 260bar;
7) Performing finish rolling, and controlling the thickness of the outlet of the steel plate to be 1.8-4.5 mm after rolling is finished; meanwhile: controlling the reduction rate of the first pass and the second pass to be not lower than 50%; the final rolling temperature is controlled to be 860-880 ℃;
8) Cooling laminar flow to coiling temperature, coiling, and controlling the coiling temperature at 560-580 ℃;
9) Naturally cooling the steel coil to not more than 70 ℃;
10 Cold rolling after conventional acid washing, controlling the cold rolling reduction to be 75-80%, and controlling the thickness of a rolling outlet to be 0.35-0.9 mm;
11 High corrosion resistant coating continuous hot dip coating:
A. firstly heating the strip steel to 640-690 ℃, then heating the strip steel to 770-790 ℃ within 40-60 seconds, and soaking;
B. rapidly cooling to 610-640 ℃ at a cooling speed of 6-15 ℃/s; slowly cooling to 585-605 ℃ at a cooling speed of 2-10 ℃/s;
C. carrying out continuous hot dip plating on the strip steel, and controlling the temperature of the plating solution to be 580-595 ℃;
D. after the galvanization is finished, the galvanized steel is passed through an air knife, the height of the air knife is controlled to be 200-260 mm, the distance between the air knife and the galvanized steel is 4-8 mm, and the pressure of the air knife is 40-80 mbar;
E. cooling, namely cooling the strip steel to not more than 200 ℃ at a cooling speed of 6-10 ℃/s after the air knife is discharged;
F. surface finishing is carried out on the strip steel, and the finishing rolling reduction rate is controlled to be 0.8-1.0%;
12 After continuous hot dip plating, the strip steel is packaged and then directly sent to a user, or the surface of the strip steel is coated;
coating for later use;
the 450MPa grade high corrosion resistant coated steel sheet produced by adopting a short process comprises the following components in percentage by weight: c:0.15 to 0.18 percent, si:0.16 to 0.20 percent, mn:0.40 to 0.60 percent, less than or equal to 0.025 percent of P, less than or equal to 0.010 percent of S,
als:0.050 to 0.060 percent, wherein N is not more than 0.010 percent, and the balance is Fe and unavoidable impurities.
2. A method for producing 450 MPa-grade high-corrosion-resistant coated steel sheet produced by a short process according to claim 1, characterized by: the coating treatment procedure:
cleaning the surface of the strip steel subjected to continuous hot dip plating; then, coating an organic layer or an inorganic coating on the surface of the strip steel twice;
and then coating and curing the organic layer or the inorganic coating, and controlling the curing temperature to be 250-310 ℃.
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