Near-net-shape endless rolling hot-based galvanized sheet and preparation method thereof

Abstract

The invention discloses a near net shape endless rolling hot-based galvanized sheet and a preparation method thereof, and belongs to the technical field of galvanized sheets. In the preparation process, the components and the technology are adjusted; in terms of the components, the smelting components are controlled; in the process, the temperature and the reduction rate are reasonably matched for hot rolling, the proportion of two-phase regions of the last sortie of a rolling mill is controlled, heat preservation is conducted after coiling, supersaturated interstitial atoms are fully separated out, and meanwhile a mixed crystal structure is avoided; and the flattening reduction rate is controlled through acid pickling, and strengthening after work hardening and aging is relieved. According to the method, the technical problems that the near-net-shape endless-rolled hot-base galvanized sheet is low in ductility, low in plastic strain ratio r value and low in strain hardening index n value, and the material is prone to cracking, ear making and other defects in the cold forming process are solved, the prepared near-net-shape endless-rolled hot-base galvanized sheet achieves the process that cold is replaced by hot, and green development is promoted.

Description

Technical Field

[0001] The invention relates to the technical field of galvanized thin plates, and in particular to a near-net-shape headless rolled hot-base galvanized thin plate and a preparation method thereof. Background Art

[0002] Galvanized sheet is one of the important deep-processing products of the steel industry. It has excellent anti-rust function and processing performance and is widely used in construction, automobile, home appliance and hardware industries. At present, the annual domestic demand exceeds 100 million tons, of which galvanized sheet with a thickness of ≤2.0mm accounts for more than 70%. The traditional process flow for producing galvanized sheet is: steelmaking-continuous casting-hot rolling-pickling-cold rolling-annealing-galvanizing-leveling. The process is long, with low production efficiency, high energy consumption and high cost. The inability of traditional hot rolling to stably produce thin-gauge hot-rolled sheets in batches is one of the main reasons for the long process flow of galvanized sheet. Traditional hot rolling can also achieve a small amount of ≤2.0mm hot-rolled thin strip production by adding insulation equipment such as insulation hoods and hot coil boxes, but there is a certain gap compared with the plate shape and surface of cold-rolled products. In recent years, near-net-shape headless rolling production lines ESP, MCCR and CASTRIP of domestic steel mills such as Nippon Steel, Shougang and Shagang have been put into production one after another. Hot-rolled thin specifications (≤2.0mm) have become their regular varieties, and the thinnest specification can be as low as 0.65mm, which can cover most specifications of existing galvanized thin sheets. Therefore, using headless hot-rolled thin specifications directly as galvanized base materials has become one of the main trends in the production of thin-gauge galvanized sheets. Headless hot-based galvanizing has the advantages of short process and low cost, and has the potential to widely replace cold-rolled galvanized thin sheets.

[0003] However, the headless rolling equipment is compactly arranged, the continuous casting speed is high, the billet is thin, and the cooling speed is fast. The supersaturated C and N content of low-carbon steel is high during hot rolling, and the control of the microstructure and texture is difficult. The direct galvanizing after hot-rolled plate pickling has obvious aging hardening, resulting in low elongation, low plastic strain ratio r value and strain hardening index n value. The material is prone to cracking and earing during cold forming. This limits the application scope of headless hot-based galvanized thin plates to replace cold-rolled galvanized thin plates. The traditional cold rolling annealing galvanizing process can improve the cold forming performance of the product in the following two ways: On the one hand, the ultra-low carbon (C≤0.0030%) is adopted, and the micro-alloying elements Ti and Nb are added at the same time. The interstitial atomic C and N elements are fixed, the aging hardening is reduced, and the component strength of the (111) texture, i.e., the γ texture, which is beneficial to cold forming, is improved. On the other hand, the microstructure, texture and performance of the material are regulated by cold rolling with large reduction and long-term aging annealing, and the cold forming performance of the galvanized thin plate is improved. However, there are technical difficulties in the continuous pouring of molten steel and the control of surface inclusions in the headless rolling production line of ultra-low carbon steel thin slabs. Since the direct galvanizing process of hot-rolled plates lacks a cold rolling annealing step, it is impossible to control the microstructure. Therefore, these technical measures are not applicable to the production of headless rolled hot-dip galvanized thin plates.

[0004] Patent CN118531316A discloses a high-formability and high-surface-quality galvanized raw material and production method for thin slab continuous casting and rolling. Good hot-rolled plate structure is obtained by controlling the composition, matching the continuous casting process and the rolling process. Among them, the thickness of the hot-rolled plate is 2.5mm-7mm, and a low-strength and high-elongation cold-rolled galvanized sheet is prepared through subsequent cold rolling, annealing and galvanizing processes. However, the preparation process of this method is long, and it mainly involves cold-based (cold-rolled annealed) galvanized products. Patent CN116005095A discloses a process for producing 0.6-4.0mm hot-based flowerless galvanized products by a modified Sendzimir process. Among them, for ESP hot-based raw materials, after pickling and leveling, reduction annealing and galvanizing, hot-based galvanizing with good surface, high dimensional accuracy and stable performance is produced. However, this method does not propose improvement in cold forming performance and corresponding process design. Patent CN109797355A discloses a production process for thin-gauge hot-rolled pickled galvanized sheet with high surface quality. Among them, the hot-rolled raw materials with headless rolling are flattened, pickled, electromagnetic induction heated, galvanized, and coiled into hot-dip galvanized coils, and the product thickness is 0.8mm-4.0mm. However, this production process mainly reduces or eliminates defects such as surface plating and pits on the strip, and alleviates the surface plating problem of hot-rolled pickled galvanized sheets, and does not involve the improvement process and technical measures for cold forming performance. At present, there are few patents on improving the cold forming performance of hot-based galvanized sheets. Therefore, it is the research and development focus of the industry to break through the key technology of "replacing cold with heat" to replace cold-rolled galvanized sheets with hot-based galvanized sheets to obtain hot-based galvanized sheets with good cold processing forming performance and strength. Summary of the invention

[0005] In view of the above-mentioned prior art, the purpose of the present invention is to provide a near-net-shape headless rolled hot-dip galvanized sheet and a preparation method thereof. The present invention prepares a near-net-shape headless rolled hot-dip galvanized sheet through thin slab continuous casting, headless hot rolling, and continuous pickling galvanizing production line. The present invention adjusts the composition and process during the preparation process: in terms of composition, the smelting composition is controlled, the content of C, N, Als, Mn and Si is controlled, and appropriate amounts of B and Ti are added to control B / N. The number of interstitial solid solution atoms C and N is reduced, the aging hardening of induction annealing after leveling is reduced, and the favorable texture strength is improved; in terms of process, the hot rolling adopts a reasonable combination of temperature and reduction rate, the proportion of the two-phase zone at the last stand of the rolling mill is controlled, the heat is kept after coiling, the supersaturated interstitial atoms are fully precipitated, and the mixed crystal structure is avoided; the pickling controls the leveling reduction rate to reduce work hardening and strengthening after aging. Finally, the technical problems of low elongation of near-net-shape headless rolled hot-dip galvanized thin plate, low plastic strain ratio r value and strain hardening index n value, and defects such as cracking and earing that are prone to occur in the material during cold forming were solved.

[0006] To achieve the above object, the present invention adopts the following technical solution:

[0007] The first aspect of the present invention provides a near-net-shape headless rolled hot-dip galvanized sheet, the chemical composition of the near-net-shape headless rolled hot-dip galvanized sheet is as follows by mass percentage: C: 0.015-0.040%, 0<Si≤0.050%, 0.10≤Mn≤0.30%, Al: 0.015-0.040%, 0<N≤0.0045%, B: 0.0015-0.0035%, Ti: 0.010-0.030%, B / N ratio: 0.50-1.0, and the rest is iron and unavoidable impurities.

[0008] Furthermore, the technical indicators of the near-net-shape headless rolled hot-dip galvanized sheet are as follows: yield strength Rel: 265-295 MPa, tensile strength Rm: 380-405 MPa, elongation A80 ≥ 35%, r value ≥ 1.20, Δr ≤ 0.20, and n value ≥ 0.19.

[0009] The second aspect of the present invention provides a method for preparing the near-net-shape headless rolled hot-dip galvanized sheet, comprising the following steps: continuously casting molten steel into a thin plate billet; headless rolling, coiling, heat preservation, and natural cooling to obtain a hot-rolled base plate; and continuously pickling, leveling, induction heating, and galvanizing the obtained hot-rolled base plate to prepare a hot-dip galvanized sheet product.

[0010] Furthermore, the thickness of the continuously cast thin plate steel billet is 100-130 mm, the thin plate steel billet is heated before headless rolling, the heating temperature is 1100-1150° C., the hot rolling final rolling temperature during headless rolling is 850-900° C., and the reduction rate of the last stand of the rolling mill is ≥35%.

[0011] Furthermore, the coiling temperature is 650-700° C., the hot rolled coil is kept warm for ≥2 hours, and then slowly cooled to room temperature.

[0012] Furthermore, during pickling and leveling, the leveling reduction rate is 1.0-1.5%, and then rapid induction heating is performed under hydrogen protection, with the highest induction heating temperature being 550-600°C.

[0013] Furthermore, the galvanizing temperature is 480-520°C, and after cooling, the steel is subjected to skin-passing, with a skin-passing rate of 0.50-1.0%.

[0014] Beneficial effects of the present invention:

[0015] (1) Through reasonable composition design, the content of Mn, Si, Al, N, and C elements is controlled, trace amounts of B and Ti elements are added in coordination, the B / N ratio is controlled, the solid solution C and N are reduced, and the elongation reduction caused by aging hardening during the galvanizing process is reduced. At the same time, the strength of the (111) texture that is beneficial to forming is increased, and the cold forming performance is improved.

[0016] (2) Control the reduction rate and final rolling temperature of the last stand of the rolling mill, select the appropriate coiling temperature, and adopt measures to precipitate the solid solution C and N elements by keeping the hot rolled coils warm at high temperature. Avoid the generation of mixed crystal structure, obtain a uniform microstructure, enhance the strength of the favorable texture (111), improve the cold forming performance, and reduce the solid solution C and N at the same time, thus reducing the aging hardening of the galvanizing process at the source.

[0017] (3) The galvanizing process selects flattening and finishing with a relatively low reduction rate, which can reduce the work hardening of this process while ensuring the plate shape and surface quality. At the same time, the induction heating and zinc pot temperature are controlled to ensure the quality of the surface zinc layer and improve its protective performance.

[0018] (4) The method of the present invention solves the technical problems of low elongation, low plastic strain ratio r value and strain hardening index n value of near-net-shape headless rolling hot-dip galvanized thin sheet, and defects such as cracking and earing that are easy to occur in the cold forming process of the material. Hot-dip galvanized thin sheet has good formability and moderate strength, and can replace conventional cold-dip galvanized products to achieve short-process production, reduce energy consumption and costs of the entire industry chain, and achieve high-quality green manufacturing by "replacing cold with heat". DETAILED DESCRIPTION

[0019] It should be noted that the following detailed descriptions are illustrative and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present application belongs.

[0020] In order to enable those skilled in the art to more clearly understand the technical solution of the present application, the technical solution of the present application will be described in detail below in conjunction with specific embodiments.

[0021] At present, most galvanized products with a thickness of ≤2.0mm adopt the traditional cold rolling annealing galvanizing process, which has a long process flow, high energy consumption and high cost. It has become a trend to use thin slab continuous casting, headless hot rolling, pickling and leveling and galvanizing processes to produce hot-based galvanized thin plates to replace cold-based galvanized products. However, within a certain strength range, improving the forming performance of the product has become its key technical problem. The present invention can produce products with high r value, n value and elongation by controlling the composition, hot rolling process, pickling and leveling and galvanizing process, improve the forming performance of the product, and provide technical support for the "replacing cold with heat" of galvanized products.

[0022] The composition design of the hot-dip galvanized sheet produced by this patent is as follows:

[0023] C is one of the most important elements that affect the microstructure and performance of steel products. It exists in the form of interstitial solid solution atoms and carbides in steel and is one of the main control elements for hot-dip galvanized products. When the C content is higher than 0.040%, the solid solution C in the finished product increases, and the subsequent aging hardening increases. When the C content is lower than 0.015%, a long period of deep decarburization is required, which increases the smelting cost. During the rolling and cooling process, less cementite Fe3C is precipitated, and the solid solution C increases.

[0024] Si is a substitutional solid solution element that reduces elongation, so the Si content needs to be controlled. In addition, when Si is ≤ 0.050%, the formation of the δ phase of the zinc-iron alloy phase is suppressed, thereby reducing the brittleness of the coating, improving the toughness of the coating, and contributing to the surface quality of the galvanized coating.

[0025] Mn is a solid solution strengthening element and an element that expands the α+γ two-phase region. Adding an appropriate amount of Mn content can avoid hot brittleness and control the phase transformation and second phase precipitation during rolling and cooling. If Mn is too high, > 0.30%, the elongation will decrease, and the two-phase region will expand, which will easily produce mixed crystal structure. If Mn is too low, < 0.10%, it will cause hot brittleness of the ingot and cause edge cracks.

[0026] Al is the main alloy element for deoxidation, and has a strong bonding force with N. During the cooling and rolling process of the ingot, AlN is precipitated. The range of Al is controlled at 0.015-0.040%. If Al is too high, the strength of the steel will be increased, and the cost will be increased. If Al is too low, the deoxidation ability will be weakened, and the solid N effect will be reduced, which is not conducive to the reduction of solid solution N.

[0027] Ti is a precipitation strengthening element, which combines with C and N to form the second phase Ti (CN), which can reduce the supersaturation of C and N, and promote the nucleation of (111) texture grains during rolling, improving the forming performance. The Ti content is controlled at 0.010-0.030%. Too low solid C and N elements have weak effects, while too high leads to increased rolling force and incomplete recrystallization during hot rolling and cooling.

[0028] Nitrogen is an unavoidable harmful element in steel. If the nitrogen content is too high (>0.0045%), the solid solution nitrogen content will increase, which will increase the aging strengthening and reduce the elongation.

[0029] B is a strong N element, and the precipitation temperature of BN is relatively high. During the continuous casting process, coarse BN can be precipitated to achieve the effect of solidifying N and reducing aging hardening. The amount of B added should be within an appropriate range. If it is too high, >0.0035%, the B element will segregate at the grain boundary of the columnar crystal, and cracks or even steel leakage will easily occur in the shell of the steel billet. If it is too low, <0.0015%, the effect of solidifying N and reducing strength is not obvious. In addition, the amount of B added is related to the N content, and it is necessary to control B / N. Controlling it at 0.50-1.0 can achieve better results.

[0030] The production process of this patented hot-dip galvanized sheet is as follows:

[0031] The thin slab adopts the rolling mode of 3+5 rough rolling and finishing rolling, and the temperature is quickly raised by induction heating between the two processes. The temperature out of the induction heating furnace is 1100-1150℃. If the temperature is too high>1150℃, the surface oxide scale is serious, and if the temperature is too low<1100℃, the dynamic recrystallization is imperfect and the final rolling temperature is difficult to guarantee.

[0032] The final rolling temperature is an important process point in the hot rolling process. The final rolling temperature is 850-900℃. If it is too low (<850℃), the final stand will roll in the two-phase region, which will easily cause mixed crystal phenomenon, increase anisotropy, reduce elongation, and cause fine precipitation of C / N. If it is too high (>900℃), the γ-α phase layer will begin to transform in the cold stage. During the cooling process, the solid solution C / N will increase, resulting in later aging.

[0033] The reduction rate of the last stand of the rolling mill is ≥35%, ensuring that the reduction rate is greater than the critical strain, ensuring the mixed crystals caused by uneven plastic deformation of the hot-rolled steel strip, and improving the (111) texture strength.

[0034] After cooling, coiling and heat preservation are conducive to the full precipitation of supersaturated solid solution C and N elements, and at the same time, they are helpful for the coarsening and homogenization of Fe3C, which is conducive to the homogenization of the organization and the formation of (111) texture. When the coiling temperature is less than 650℃, the cooling intensity is too large, and C and N precipitate finely. When the coiling temperature is greater than 700℃, the precipitate phase is coarse and the grains are uneven. The hot rolled coil is kept warm for a time of ≥2h to provide kinetic conditions for the full precipitation and growth of the precipitate phase, achieve the effect of early high temperature aging, reduce the solid solution C and N, achieve the effect of long-term online annealing, and avoid the deterioration of elongation caused by low temperature aging of galvanized induction heating.

[0035] Control the leveling reduction rate of the galvanizing process to 1.0-1.5%, and the reduction rate ≥1.0% to ensure the flatness of the plate surface. At the same time, the reduction rate should be minimized, and the reduction rate ≤1.5% to reduce the work hardening caused by leveling and the aging hardening caused by induction heating. Control the induction heating temperature, the temperature is 550-600℃, to ensure the temperature of the steel strip entering the zinc pot. The zinc pot temperature is 480-520℃. If the temperature is lower than 480℃, the galvanized layer will not form well. If the temperature is higher than 520℃, it is difficult to control the thickness of the galvanized layer. Control the skin-clearing reduction rate of the steel strip after galvanizing to 0.50-1.0%, while ensuring the plate shape and surface quality, reduce the surface work hardening and obtain good performance.

[0036] After smelting, thin slab continuous casting, headless rolling, continuous pickling and flat galvanizing, the final product is Rel: 265-295MPa, tensile strength Rm: 380-405MPa, elongation A80 ≥ 35%, r value ≥ 1.20, Δr ≤ 0.20, n value ≥ 0.19. The product has excellent forming performance and no cold forming defects such as cracking and earing. The promotion of this product and technology will promote the application scope of low-carbon galvanized products to replace cold with hot, and provide technical support for energy saving and cost reduction of the entire supply chain.

[0037] The experimental materials used in the examples of the present invention but not specifically described are all conventional experimental materials in the art and can be purchased through commercial channels.

[0038] Embodiment 1:

[0039] When producing near-net-shape headless rolled hot-dip galvanized thin plates, the core idea of ​​the composition process design is to control the C / N content of interstitial solid solution atoms, reduce aging hardening and work hardening, improve the (111) texture strength, avoid the generation of mixed crystal structure, and thus improve the r value, n value and elongation.

[0040] The production method comprises the following steps:

[0041] Take the qualified molten steel with target composition, and obtain 0.65-2.0mm thick hot-rolled base plate through thin slab continuous casting, endless rolling, coiling, insulation and natural cooling. Then, it is continuously pickled, leveled, induction heated and galvanized to prepare hot-base thin-gauge galvanized products with good formability.

[0042] Specifically:

[0043] In terms of composition, the designed mass percentage of the hot-rolled pickled sheet is: C: 0.015-0.040%, Si≤0.050%, 0.10≤Mn≤0.30%, Al: 0.015-0.040%, N≤0.0045%, B: 0.0015-0.0035%, Ti: 0.010-0.030%, B / N: 0.50-1.0, and the rest is iron and unavoidable impurities. In terms of process, the molten steel smelted according to the target composition is continuously cast into thin slabs, endlessly rolled into hot-rolled base plates, and then passed through a continuous pickling and galvanizing production line to obtain hot-base galvanized sheets. The continuous casting billet thickness is 100-130mm, and the appropriate heating temperature is used, the heating temperature is 1100-1150℃, the hot rolling final rolling temperature is 850-900℃, the rolling mill end stand reduction rate is ≥35%, and the coiling is air-cooled, the coiling temperature is 650-700℃, the hot rolled coil is kept warm, the holding time is ≥2h, and it is slowly cooled to room temperature. Pickling and leveling are carried out before galvanizing, the leveling reduction rate is 1.0-1.5%, and rapid induction heating is carried out under hydrogen protection, the maximum induction heating temperature is 550-600℃, and the zinc pot is galvanized, the zinc pot temperature is 480-520℃, and the zinc pot is air-cooled and then the skin is smoothed, and the skin smoothing rate is 0.50-1.0%.

[0044] Example 2-Example 10:

[0045] The products were prepared with different molten steel compositions and different process parameters, and then the products were tested comparatively. The molten steel compositions are shown in Table 1 below.

[0046] Table 1 Molten steel composition (wt.%)

[0047]

[0048] The preparation process is as follows:

[0049] The molten steel obtained according to the molten steel composition in Table 1 is continuously cast into thin slabs; the hot-rolled substrate is obtained by endless rolling, coiling, heat preservation and natural cooling; the obtained hot-rolled substrate is continuously pickled and leveled, induction heated and galvanized to prepare a hot-base galvanized sheet product. The process parameters for preparing the hot-rolled substrate are shown in Table 2, and the process parameters for pickling and leveling and galvanizing are shown in Table 3.

[0050] Table 2 Hot-rolled substrate preparation process

[0051]

[0052] Table 3 Pickling, leveling and galvanizing process

[0053]

[0054] Comparative Example 1-Comparative Example 3:

[0055] The products were prepared with different molten steel compositions and different process parameters, and then the products were tested comparatively. The molten steel compositions are shown in Table 4 below.

[0056] Table 4 Molten steel composition (wt.%)

[0057]

[0058] The preparation process is as follows:

[0059] The molten steel obtained according to the molten steel composition in Table 4 is continuously cast into thin slabs; endless rolling, coiling, and natural cooling are performed to obtain hot-rolled substrates; the obtained hot-rolled substrates are continuously pickled, leveled, induction heated, and galvanized to prepare hot-base galvanized thin plate products. The process parameters for preparing hot-rolled substrates are shown in Table 5, and the process parameters for pickling, leveling, and galvanizing are shown in Table 6.

[0060] Table 5 Hot-rolled substrate preparation process

[0061]

[0062] Table 6 Pickling, leveling and galvanizing process

[0063]

[0064] Test Example 1:

[0065] The hot-dip galvanized sheet products obtained in Examples 2 to 10 and Comparative Examples 1 to 3 were tested, and the test items and standards were as follows:

[0066] The test method for thickness specifications is based on "GB / T708-2019 Dimensions, shapes, weights and allowable deviations of cold-rolled steel sheets and strips";

[0067] The test methods for yield strength, tensile strength and elongation A80 are based on "GB / T228.1-2021 Tensile test of metal materials Part 1: Room temperature test method";

[0068] The test method of r value and Δr is based on "GB / T 5027-2016 Determination of plastic strain ratio (r value) of metal sheets and strips";

[0069] The test method of n value is based on "GB / T 5028-2008 Determination of tensile strain hardening index (n value) of metal sheets and strips";

[0070] The product index test results are shown in Table 7.

[0071] Table 7 Product index test

[0072]

[0073]

[0074] It can be seen from the results in Table 7 that compared with the products of Comparative Examples 1-3, the products of Examples 2-10 of the present invention, through the control of composition and process, finally prepare hot-dip galvanized thin plates with excellent cold forming performance, and their technical indicators are as follows: yield strength Rel: 265-295MPa, tensile strength Rm: 380-405MPa, elongation A80 ≥ 35%, r value ≥ 1.20, Δr ≤ 0.20, n value ≥ 0.19. In the preparation process, the hot-dip galvanized thin plate strip of the present invention adopts a unique composition ratio and preparation production process, and the product has excellent mechanical properties and forming properties, good cold working performance, and no defects such as cracking and earing. The present invention has fewer preparation steps, omits ordinary cold rolling and continuous annealing processes, and can greatly reduce energy consumption and manufacturing costs. The present invention can produce products with high r value, n value and elongation, improve the forming performance of the products, and provide technical support for the "replacing cold with heat" of galvanized products. The product of the present invention can be applied to hardware, home appliances, door industry, auto parts and other industries, expanding the industry application scope of products that replace cold with heat, and promoting the reduction of production costs of the entire industry chain.

[0075] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A near-net-shape headless rolled hot-dip galvanized sheet, characterized in that: The chemical composition of the near-net-shape headless rolled hot-dip galvanized sheet is as follows by mass percentage: C: 0.015-0.040%, 0<Si≤0.050%, 0.10≤Mn≤0.30%, Al: 0.015-0.040%, 0<N≤0.0045%, B: 0.0015-0.0035%, Ti: 0.010-0.030%, B / N ratio: 0.50-1.0, and the rest is iron and unavoidable impurities.

2. The near-net-shape endlessly rolled hot-dip galvanized sheet according to claim 1, characterized in that: The technical indicators of the near-net-shape headless rolled hot-dip galvanized sheet are as follows: yield strength Rel: 265-295 MPa, tensile strength Rm: 380-405 MPa, elongation A80≥35%, r value≥1.20, Δr≤0.20, and n value≥0.

19.

3. A method for preparing the near-net-shape endlessly rolled hot-dip galvanized sheet according to claim 1, characterized in that: The method comprises the following steps: continuously casting molten steel into thin plate billets; endlessly rolling, coiling, heat preservation and natural cooling to obtain hot-rolled base plates; continuously pickling and leveling, induction heating and galvanizing the obtained hot-rolled base plates to prepare hot-base galvanized thin plate products.

4. The method for preparing the near-net-shape endlessly rolled hot-dip galvanized sheet according to claim 3, characterized in that: The thickness of the continuously cast thin plate steel billet is 100-130mm. The thin plate steel billet is heated before headless rolling, and the heating temperature is 1100-1150℃. The hot rolling final rolling temperature during headless rolling is 850-900℃, and the reduction rate of the last stand of the rolling mill is ≥35%.

5. The method for preparing the near-net-shape headless rolled hot-dip galvanized sheet according to claim 3, characterized in that: The coiling temperature is 650-700℃, the hot rolled coil is kept warm for ≥2h, and then slowly cooled to room temperature.

6. The method for preparing the near-net-shape endlessly rolled hot-dip galvanized sheet according to claim 3, characterized in that: During pickling and leveling, the leveling reduction rate is 1.0-1.5%, and then rapid induction heating is performed under hydrogen protection, with the maximum induction heating temperature being 550-600°C.

7. The method for preparing the near-net-shape endlessly rolled hot-dip galvanized sheet according to claim 3, characterized in that: The galvanizing temperature is 480-520℃, and the skin finishing is carried out after cooling, and the skin finishing rate is 0.50-1.0%.

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