Color-coated steel plate for curtain wall without incision corrosion and production process thereof

Abstract

This invention belongs to the technical field of color-coated steel sheets and discloses a color-coated steel sheet for curtain walls without notch corrosion and its production process. The color-coated steel sheet includes a substrate, a metal plating layer, and a coating layer; wherein the chemical composition of the substrate, by weight percentage, is: C: 0.0005–0.007%, Si: 0.06–0.15%, Mn: 0.50–1.0%, P: 0.050–0.090%, S: ≤0.012%, Als: 0.012–0.060%, Nb: 0–0.040%, Ti: 0.019–0.060%, N: ≤0.006%, with the balance being Fe and unavoidable impurities; the metal plating layer is a high-alumina plating layer or a pure zinc plating layer. This invention employs an ultra-low content of interstitial solid solution atoms, an appropriate amount of solid solution strengthening atoms, and trace alloying elements, matched with a suitable fine grain structure control process and a high-durability, non-cutting corrosion coating process, to achieve the production and manufacturing of non-cutting corrosion, high-durability, and highly formable stamped color-coated steel sheets.

Description

Technical Field

[0001] This invention belongs to the technical field of color-coated steel sheets, specifically relating to a color-coated steel sheet for curtain walls that is free from notch corrosion and its production process. Background Technology

[0002] Metal curtain walls are a new type of building curtain wall. Due to the excellent workability, diverse colors, and good safety of metal sheets, they can adapt to various complex designs, giving architects enormous creative freedom and thus are highly favored by them. Currently, aluminum alloy sheets are the most commonly used panel materials for metal curtain walls. However, they are not only expensive, but also have high energy consumption and carbon emissions during manufacturing, low recycling rates, and high maintenance costs. In contrast, color-coated steel sheets are more economical and have broad development prospects.

[0003] With rapid societal development, people have raised higher requirements for curtain walls, especially luxury decorative curtain walls, demanding green, economical, high-performance, and high-durability qualities. However, existing color-coated steel sheet products suffer from the following main problems in production and application: 1) Wrinkling and cracking are prone to occur during stamping, failing to meet the high formability requirements of luxury decorative curtain walls, especially the forming performance requirements of the tongue-and-groove joints on all four sides; 2) During service, the continuously produced strip steel needs to be cut into blanks of required sizes, resulting in cut edges. The exposed steel base at these cut edges is susceptible to cut-edge corrosion, failing to meet the requirements of corrosion-free and high-durability performance for luxury decorative curtain walls. Therefore, these factors significantly limit the application and promotion of color-coated steel sheets. Summary of the Invention

[0004] The technical problem to be solved by this invention is to address the shortcomings of existing technologies by providing a non-corrosion-resistant color-coated steel sheet for curtain walls and its production process. The invention employs an ultra-low content of interstitial solid solution atoms, an appropriate amount of solid solution strengthening atoms, and trace alloying elements, matched with a suitable fine grain structure control process and a high-durability, non-corrosion-resistant coating process. This enables the production of non-corrosion-resistant, high-durability, and highly formable stamped color-coated steel sheets, meeting the green, economical, and highly durable requirements of luxury decorative curtain walls.

[0005] To solve the technical problem proposed by the present invention, the present invention provides a pre-coated steel sheet for curtain walls that is free from notch corrosion, the pre-coated steel sheet comprising a substrate, a metal plating layer and a coating layer.

[0006] In the above scheme, the chemical composition of the substrate by weight percentage is as follows: C: 0.0005-0.007%, Si: 0.06-0.15%, Mn: 0.50-1.0%, P: 0.050-0.090%, S: ≤0.012%, Als: 0.012-0.060%, Nb: 0-0.040%, Ti: 0.019-0.060%, N: ≤0.006%, with the balance being Fe and unavoidable impurities.

[0007] In the above scheme, the chemical composition of the substrate satisfies Ti Re ≥0.003%, Ti Re =Ti-3.42×N-1.5×S-4×C, where Ti, N, S, and C are the mass percentages of Ti, N, S, and C in the substrate, respectively.

[0008] In the above scheme, the metal coating is a high-aluminum coating or a pure zinc coating.

[0009] Furthermore, the chemical composition of the high-aluminum coating, by weight percentage, is: Al: 53-57%, Zn: 38-45%, Mg: 1.5-4%, Fe: ≤0.52%, with the remainder being unavoidable impurities.

[0010] Furthermore, the thickness of the high-aluminum coating is an average of 60–125 g / m² on three points on a single side. 2 .

[0011] Furthermore, the chemical composition of the pure zinc coating, by weight percentage, is: Zn: ≥99%, Al: 0.20~0.30%, Fe: ≤0.02%, with the remainder being unavoidable impurities.

[0012] Furthermore, the thickness of the pure zinc coating is an average of 120–225 g / m² on three points on one side. 2 .

[0013] In the above scheme, the coating is high-durability polyester (HDP) or polyvinylidene fluoride (PVDF).

[0014] In the above scheme, the thickness of the coating is 20-40 μm.

[0015] In the above scheme, the thickness of the color-coated steel sheet is 0.35-2.0 mm, the yield strength is ≥250 MPa, the tensile strength is ≥360 MPa, and the elongation is ≥32%.

[0016] The present invention also provides a production process for color-coated steel sheets for curtain walls that are free from notch corrosion, including preparing a substrate, continuous hot-dip galvanizing of a metal coating, and applying a coating layer.

[0017] In the above scheme, the substrate fabrication steps include:

[0018] 1) After desulfurization, the molten iron is smelted and refined, and then continuously cast into billets;

[0019] 2) After heating the billet, rough rolling and finish rolling are performed to obtain strip steel;

[0020] 3) Cool the strip steel to the coiling temperature and then coil it to obtain a steel coil;

[0021] 4) After cooling the steel coil, pickling and cold rolling are performed to obtain the substrate.

[0022] Furthermore, the sulfur content in the molten iron desulfurization is controlled to be ≤0.002%.

[0023] Furthermore, the continuous casting control process involves a ladle molten steel volume of 30–35 t and a billet thickness of 210–250 mm.

[0024] Furthermore, the heating time of the cast billet is ≥150 min, and the furnace exit temperature is 1200~1280℃.

[0025] Furthermore, the roughing mill exit temperature is 1050–1080°C, and the finishing mill final rolling temperature is 880–920°C.

[0026] Furthermore, the winding temperature at the head and tail of the steel coil is 700–725°C, and the winding temperature at the middle of the steel coil is 650–690°C.

[0027] Furthermore, the total length of the steel coil is 500-700m, the head length is 60-100m, the tail length is 70-100m, and the part other than the head and tail is called the middle part.

[0028] Furthermore, the wavy shape of the strip after the steel coil is flattened is as follows: wave height ≤ 8mm, convexity 20~50μm, and local high point ≤ 8μm.

[0029] Furthermore, the steel coil is air-cooled or water-cooled to ≤60℃ and then pickled and cold-rolled.

[0030] Furthermore, the total reduction rate of the cold continuous rolling is 75-80%.

[0031] Furthermore, the wave shape of the substrate is: steepness ≤2%, wave height ≤3mm.

[0032] In the above scheme, when the metal coating is a high-aluminum coating, the continuous hot-dip galvanizing step includes:

[0033] 1) The substrate is placed in the annealing furnace and heated to 770-800°C at a heating rate of 2-10°C / s for homogenization, while the furnace pressure is controlled at 20-80Pa. Then, it is rapidly cooled to 620-650°C at a cooling rate of 25-45°C / s, while the dew point of the rapid cooling section is controlled to be <-20°C. Subsequently, it is slowly cooled to 580-630°C at a cooling rate of 8-20°C / s, while the hydrogen volume percentage in the furnace nose is controlled to be 10-30%.

[0034] 2) After annealing, the substrate is placed in a zinc pot for continuous hot-dip galvanizing. The temperature of the galvanizing solution in the zinc pot is 590-600℃.

[0035] 3) After the hot-dip galvanized steel sheet exits the zinc pot, it passes through an air knife. The air knife height is controlled at 180-400 mm, the air knife distance is 5-15 mm, and the air knife angle is 0--5°.

[0036] 4) The steel plate after the air knife is rapidly cooled to ≤280℃ at a cooling rate of 10~23℃ / s, and then surface-finished with a finishing elongation of 1.0~1.2%.

[0037] In the above scheme, when the metal coating is a pure zinc coating, the continuous hot-dip galvanizing step includes:

[0038] 1) The substrate is placed in an annealing furnace and heated to 770-800°C at a heating rate of 2-6°C / s and held at that temperature. Then it is rapidly cooled to 465-485°C at a cooling rate of 28-50°C / s.

[0039] 2) After annealing, the substrate is placed in a zinc pot for continuous hot-dip galvanizing. The temperature of the galvanizing solution in the zinc pot is 455-465℃.

[0040] 3) After the hot-dip galvanized steel sheet exits the zinc pot, it passes through an air knife. The air knife height is controlled at 200-700 mm, the air knife distance at 7-16 mm, and the air knife pressure at 60-400 mbar.

[0041] 4) After the air knife is removed, the steel plate is rapidly cooled to ≤200℃ at a cooling rate of 5~30℃ / s, and then surface-finished with a finishing elongation of 1.0~1.2%.

[0042] In the above scheme, the coating application step includes:

[0043] The surface of the steel plate after continuous hot-dip galvanizing is cleaned, and then a preliminary coating and a fine coating are applied. After coating, the steel plate enters a curing oven to cure the coating, thus obtaining a color-coated steel plate.

[0044] Furthermore, the temperature of the cleaning solution used for cleaning is 35–40°C.

[0045] Furthermore, the coating process controls the pressure of the conveyor roller to be 1780–1820 kg and the pressure of the coating roller to be 100–300 kg.

[0046] Furthermore, the temperature inside the curing oven is 250–350°C.

[0047] The substrate composition design in this invention is based on the following principles:

[0048] C: Carbon is an interstitial solid solution element. While its addition in large quantities can significantly increase the strength of steel, its solid solubility in steel decreases at room temperature. Free carbon atoms have a certain diffusion capacity, which can cause them to detach from dislocations and slip, thus deteriorating the surface quality. On the other hand, excessive interstitial solid solution carbon atoms can lead to a significant reduction in the {111} component in the recrystallization texture, thereby worsening the formability of the steel. Therefore, its content is limited to the range of 0.0005% to 0.007%.

[0049] Si: Silicon has a strong solid solution strengthening effect, second only to P. However, a high Si content is detrimental to formability. Furthermore, a high silicon content in steel can cause a dramatic increase in the Fe-Zn alloy phase in the coating, worsening coating adhesion and affecting the surface quality after hot-dip galvanizing. Therefore, its content is limited to the range of 0.06–0.15%.

[0050] Mn: Manganese plays a solid solution strengthening role, ensuring that steel has high strength. However, a high Mn content is detrimental to formability, especially when there are more C and N atoms in the steel. The severe damage to formability caused by Mn is due to the interaction between Mn and interstitial atoms. Therefore, its content is limited to the range of 0.50% to 1.0%.

[0051] Al (Al₂O₃) acts as a deoxidizer in steel, primarily removing oxygen dissolved in the molten steel during oxygen blowing smelting. Simultaneously, Al acts as an oxygen stabilizer, inhibiting nitrogen solid solution in ferrite, eliminating strain aging, and improving low-temperature plasticity. However, excessive Al content increases inclusions in the steel, affecting its mechanical properties. Therefore, its content is limited to the range of 0.012–0.060%.

[0052] Phosphorus (P): A solid solution strengthening element, it is the element that most effectively improves the strength of ferrite compared to other substitutional alloying elements. Adding an appropriate amount of P to steel not only increases its strength but also does not reduce its deep-drawing properties. Furthermore, P does not affect the adhesion of the galvanized layer. However, higher P levels can easily cause secondary processing embrittlement and weaken favorable textures, reducing the r-value of the steel. Therefore, its content should be controlled below 0.1%. Thus, its content is controlled within the range of 0.050–0.090%.

[0053] S: Sulfur is a very harmful element. Sulfur in steel often exists in the form of manganese sulfides. These sulfide inclusions deteriorate the toughness of steel and cause anisotropy in its properties. Therefore, the sulfur content in steel should be controlled as low as possible. Based on manufacturing cost considerations, the sulfur content in steel is controlled below 0.012%.

[0054] N: Nitrogen is an element that is harmful to formability. Taking into account smelting capacity and cost, the nitrogen content in steel is controlled below 0.006%.

[0055] Ti and Nb: The addition of microalloying elements niobium and titanium is crucial in production. The addition of Ti and Nb completely fixes interstitial C and N atoms in the steel, thereby purifying the ferrite matrix and ensuring good formability of the experimental steel. Simultaneously, the addition of Ti and Nb refines the ferrite grains and promotes precipitation strengthening. Based on the precipitation sequence of two-phase particles in the steel after Ti treatment, and considering the effect of Nb addition on the precipitation of two-phase particles, 0.019–0.060% Ti and 0–0.040% Nb are added to the steel in a balanced manner. If Ti is added alone, the concentration of Ti in the steel should be controlled to ≥0.003%. Re Ti Re =Ti - 3.42 × N - 1.5 × S - 4 × C.

[0056] The process design of this invention is based on the following principles:

[0057] This invention achieves a good sheet shape from hot-rolled raw material coils by controlling the temperature of hot roughing and high-temperature finishing, as well as the temperature of the coil head, tail, and middle winding, while ensuring a certain proportion of favorable fiber texture in the steel. Subsequently, by rationally matching the large cold rolling reduction rate, annealing temperature, and cooling rate, the product achieves high strength while obtaining a certain proportion of favorable texture, thereby ensuring that the invented steel has good formability. Finally, by matching and controlling the coating thickness, composition, and coating, it achieves no notch corrosion and high durability in service.

[0058] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0059] This invention employs an ultra-low content of interstitial solid solution atoms, an appropriate amount of solid solution strengthening atoms, and trace alloying elements, matched with a suitable fine grain structure control process and a high-durability, non-cutting corrosion coating process. This enables the production of non-cutting corrosion, high formability, and high-durability stamped color-coated steel sheets, meeting the green, economical, and highly durable requirements of luxury decorative curtain walls. Attached Figure Description

[0060] Figure 1 This is a microstructure photograph of the substrate of Embodiment 1 of the present invention. Detailed Implementation

[0061] To better understand the present invention, the following embodiments further illustrate the content of the present invention, but the content of the present invention is not limited to the following embodiments.

[0062] Examples 1-6 and Comparative Examples 1-2

[0063] The color-coated steel sheets in the following examples and comparative examples include a substrate, a metal plating layer, and a coating layer, wherein the chemical composition of the substrate is shown in Table 1.

[0064] Table 1. Chemical composition (wt.%) of the substrates in the examples and comparative examples.

[0065]

[0066]

[0067] The substrate preparation steps in Examples 1-6 include:

[0068] 1) Desulfurization of molten iron, controlling S≤0.002%;

[0069] 2) After smelting and refining, it is continuously cast into a billet. The amount of molten steel in the ladle during continuous casting is 30-35t, and the thickness of the billet is 210-250mm.

[0070] 3) Heating of the billet, heating time ≥150min, furnace exit temperature 1200~1280℃;

[0071] 4) Rough rolling and finish rolling are performed to obtain strip steel. The exit temperature of rough rolling is 1050-1080℃, and the final rolling temperature of finish rolling is 880-920℃.

[0072] 5) The strip is cooled to the coiling temperature and then coiled to obtain a steel coil. The coiling temperature at the head and tail of the steel coil is 700-725℃, and the coiling temperature in the middle of the steel coil is 650-690℃.

[0073] 6) After the steel coil is cooled by air or water to ≤60℃, it is pickled and cold rolled continuously. The total reduction rate of cold rolling is 75-80%, and a substrate is obtained.

[0074] The steps for preparing the substrate in Comparative Examples 1 and 2 are the same as those in Examples 1 to 6, except for the control of process parameters, as detailed in Tables 2 and 3.

[0075] Table 2. Main process parameters for substrate preparation in the examples and comparative examples (steps 1-4)

[0076]

[0077] Table 3. Main process parameters for substrate preparation in the examples and comparative examples (steps 5-6)

[0078]

[0079]

[0080] The chemical composition and thickness of the metal coating of the color-coated steel sheets in the following examples and comparative examples are shown in Table 4.

[0081] Table 4. Chemical composition and thickness of the metal coatings in the examples and comparative examples.

[0082] serial number Metal plating Al(％) Zn(%) Mg (%) Fe (%) <![CDATA[Single-sided thickness (g / m 2 )]]> Example 1 High-alumina coating 54 43.96 1.8 0.24 76 Example 2 High-alumina coating 53.8 43.62 2.3 0.28 64 Example 3 High-alumina coating 56.98 39.7 3.1 0.22 103 Example 4 High-alumina coating 55.3 40.53 3.99 0.18 119 Example 5 High-alumina coating 53.05 44.99 1.65 0.31 124 Example 6 pure zinc coating 0.23 99.76 0 0.008 176 Comparative Example 1 pure zinc coating 0.24 99.75 0 0.011 56 Comparative Example 2 pure zinc coating 0.22 99.77 0 0.012 58

[0083] The steps of continuous hot-dip plating of metal coatings in Examples 1-5 include:

[0084] 1) The substrate is placed in the annealing furnace and heated to 770-800°C at a heating rate of 2-10°C / s for homogenization, while the furnace pressure is controlled at 20-80Pa. Then, it is rapidly cooled to 620-650°C at a cooling rate of 25-45°C / s, while the dew point of the rapid cooling section is controlled to be <-20°C. Subsequently, it is slowly cooled to 580-630°C at a cooling rate of 8-20°C / s, while the hydrogen volume percentage in the furnace nose is controlled to be 10-30%.

[0085] 2) After annealing, the substrate is placed in a zinc pot for continuous hot-dip galvanizing. The temperature of the galvanizing solution in the zinc pot is 590-600℃.

[0086] 3) After the hot-dip galvanized steel sheet exits the zinc pot, it passes through an air knife. The air knife height is controlled at 180-400 mm, the air knife distance is 5-15 mm, and the air knife angle is 0--5°.

[0087] 4) The steel plate after the air knife is rapidly cooled to ≤280℃ at a cooling rate of 10~23℃ / s, and then surface-finished with a finishing elongation of 1.0~1.2%.

[0088] The continuous hot-dip plating steps for the metal coating in Example 6 include:

[0089] 1) The substrate is placed in an annealing furnace and heated to 770-800°C at a heating rate of 2-6°C / s and held at that temperature. Then it is rapidly cooled to 465-485°C at a cooling rate of 28-50°C / s.

[0090] 2) After annealing, the substrate is placed in a zinc pot for continuous hot-dip galvanizing. The temperature of the galvanizing solution in the zinc pot is 455-465℃.

[0091] 3) After the hot-dip galvanized steel sheet exits the zinc pot, it passes through an air knife. The air knife height is controlled at 200-700 mm, the air knife distance at 7-16 mm, and the air knife pressure at 60-400 mbar.

[0092] 4) After the air knife is removed, the steel plate is rapidly cooled to ≤200℃ at a cooling rate of 5~30℃ / s, and then surface-finished with a finishing elongation of 1.0~1.2%.

[0093] The steps of continuous hot-dip plating of metal coatings in Comparative Examples 1 and 2 are the same as those in Example 6, except for the control of process parameters, as detailed in Tables 5 and 6.

[0094] Table 5. Main process parameters for continuous hot-dip plating of metal coatings in the examples and comparative examples (step 1)

[0095]

[0096] Table 6. Main process parameters for continuous hot-dip plating of metal coatings in the examples and comparative examples (steps 2-4)

[0097]

[0098]

[0099] The chemical composition and thickness of the coating of the color-coated steel sheets in the following examples and comparative examples are shown in Table 7.

[0100] Table 7. Key parameters of the coatings in the examples and comparative examples.

[0101] serial number Coating components Coating thickness μm Material roller pressure (Kg) Coating roller pressure (Kg) Curing temperature ℃ Example 1 PVDF 23 1801 256 310 Example 2 PVDF 22 1819 282 345 Example 3 PVDF 24 1800 206 300 Example 4 PVDF 26 1796 182 339 Example 5 HDP 31 1789 165 305 Example 6 HDP 29 1792 161 309 Comparative Example 1 HDP 15 1253 273 301 Comparative Example 2 HDP 12 1287 286 306

[0102] The coating application steps in Examples 1-6 include:

[0103] 1) Clean the surface of the steel plate after continuous hot-dip galvanizing. The temperature of the cleaning solution should be 35-40℃.

[0104] 2) Perform initial coating and fine coating, with a material roller pressure of 1780-1820 kg and a coating roller pressure of 100-300 kg;

[0105] 3) The coating is cured in a curing oven at a temperature of 250-350℃ to obtain a color-coated steel sheet.

[0106] The coating steps in Comparative Examples 1 and 2 are the same as those in Examples 1 to 6, except for the control of process parameters, as detailed in Table 7.

[0107] Performance tests were conducted on the color-coated steel sheets of each embodiment and comparative example, and the results are shown in Table 8. The determination of the texture index was based on YB / T 5360. The determination of the 48-hour neutral salt spray test, the ultraviolet accelerated aging test, and the 1000-hour neutral salt spray test of the notched specimens were based on GB / T 13448. Specifically, the 48-hour neutral salt spray test of the notched specimens involved scribing the surface of the specimen and then placing it in a neutral salt spray environment. After 48 hours, the specimen was removed and the corrosion width at the scribing point was measured. The test conditions for the ultraviolet accelerated aging test were as follows: 12 hours per cycle, 8 hours of ultraviolet irradiation at a black plate temperature of 60℃±3℃, 4 hours of condensation at a black plate temperature of 50℃±3℃.

[0108] Table 8. Performance test results of color-coated steel sheets in the examples and comparative examples.

[0109]

[0110]

[0111] Combination Figure 1 Table 5 and the performance test results of each embodiment and comparative example are analyzed:

[0112] Micrographs of the substrate in Example 1 are shown below. Figure 1 As shown, the substrate has a uniform structure, which ensures uniform metal flow during the stamping process and facilitates the successful forming of complex parts.

[0113] As can be seen from the data in Table 5, the color-coated steel sheets in Examples 1-6 of this invention not only have a low yield strength ratio and a high elongation, but also a high texture index, indicating that the steel of this invention has a high proportion of (111) favorable texture, suitable for complex deformation, thus ensuring a reasonable balance between high strength and high formability. Meanwhile, the steel of this invention exhibits good aging T-bending performance. The 48-hour neutral salt spray test of the scribing specimen, the accelerated aging test under ultraviolet light, and the 1000-hour neutral salt spray test of the notched specimen demonstrate that the steel of this invention has good durability and notched corrosion resistance.

[0114] In summary, this invention, through the design of ultra-low content interstitial solid solution atoms, matching appropriate amounts of solid solution strengthening atoms and trace alloying elements, matching suitable microstructure and (111) texture control technology and high corrosion resistance and no-notch corrosion coating process control technology, has successfully achieved the invention steel to achieve good formability, economy, no-notch corrosion, high durability and aesthetic requirements after stamping, while meeting the strength requirements. It meets the green, economical and high-durability use needs of the luxury building decoration industry, and has great significance for saving social resources and improving the service performance of the building industry.

[0115] The above embodiments are merely examples for clear illustration and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations, and any obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A pre-coated steel sheet for curtain walls that is free from nick-and-corrosion, comprising a substrate, a metal plating layer, and a coating layer, characterized in that, The chemical composition of the substrate, by weight percentage, is as follows: C: 0.0035~0.007%, Si: 0.08~0.15%, Mn: 0.50~1.0%, P: 0.063~0.090%, S: ≤0.012%, Als: 0.012~0.060%, Nb: 0~0.0024%, Ti: 0.0045~0.060%, N: ≤0.006%, with the balance being Fe and unavoidable impurities, and satisfying the requirement of Ti... Re ≥0.003%, Ti Re =Ti - 3.42 × N - 1.5 × S - 4 × C; The metal coating is a high-alumina coating or a pure zinc coating; the chemical composition of the high-alumina coating, by weight percentage, is: Al: 53~57%, Zn: 38~45%, Mg: 1.5~4%, Fe: ≤0.52%, with the remainder being unavoidable impurities, and the thickness is an average of 60~125 g / m² on three points on a single side. 2 The chemical composition of the pure zinc coating, by weight percentage, is: Zn: ≥99%, Al: 0.20~0.30%, Fe: ≤0.02%, with the remainder being unavoidable impurities. The thickness is an average of 120~225 g / m² on three points on a single side. 2 ; The coating is a high-durability polyester HDP or polyvinylidene fluoride PVDF; the thickness of the coating is 20~40μm. The production process of the color-coated steel sheet for the curtain wall includes substrate preparation, continuous hot-dip galvanizing of the metal coating, and coating application. The substrate preparation steps include: 1) Desulfurization of molten iron, controlling S≤0.002%; 2) After smelting and refining, it is continuously cast into a billet. The amount of molten steel in the ladle during continuous casting is 30~35t, and the thickness of the billet is 210~250mm. 3) Heating of the billet, heating time ≥150min, furnace exit temperature 1200~1220℃; 4) Rough rolling and finish rolling are performed to obtain strip steel. The exit temperature of rough rolling is 1050~1080℃, and the final rolling temperature of finish rolling is 880~915℃. 5) The strip is cooled to the coiling temperature by laminar flow and then coiled to obtain a steel coil. The coiling temperature at the head and tail of the steel coil is 700~709℃, and the coiling temperature in the middle of the steel coil is 650~690℃. The wave shape of the steel coil after leveling is: wave height ≤8mm, convexity 20~50μm, and local high point ≤8μm. 6) After the steel coil is cooled by air or water to ≤60℃, it is pickled and cold rolled continuously. The total reduction rate of cold rolling is 75~80% to obtain a substrate. The waviness of the substrate is: steepness ≤2% and waviness height ≤3mm. The continuous hot-dip plating step of the metal coating includes: When the metal coating is a high-alumina coating, the substrate enters an annealing furnace and is heated to 770-800°C at a heating rate of 2-10°C / s for homogenization. Then, it is rapidly cooled to 620-650°C at a cooling rate of 25-45°C / s, and then slowly cooled to 580-630°C at a cooling rate of 8-20°C / s. The annealed substrate is then placed in a zinc pot for continuous hot-dip galvanizing. When the metal coating is a pure zinc coating, the substrate enters an annealing furnace and is heated to 770-800°C at a heating rate of 2-6°C / s and held at that temperature. Then, it is rapidly cooled to 465-485°C at a cooling rate of 28-50°C / s. The annealed substrate is then placed in a zinc pot for continuous hot-dip galvanizing.

2. The non-cutting corrosion-resistant color-coated steel sheet for curtain walls according to claim 1, characterized in that, The thickness of the color-coated steel sheet is 0.35~2.0mm, the yield strength is ≥250MPa, the tensile strength is ≥360MPa, and the elongation is ≥32%.

3. A production process for non-cut-corrosion-resistant color-coated steel sheets for curtain walls as described in claim 1 or 2, comprising preparing a substrate, continuous hot-dip galvanizing of a metal coating, and applying a coating layer, characterized in that, The substrate fabrication steps include: 1) Desulfurization of molten iron, controlling S≤0.002%; 2) After smelting and refining, it is continuously cast into a billet. The amount of molten steel in the ladle during continuous casting is 30~35t, and the thickness of the billet is 210~250mm. 3) Heating of the billet, heating time ≥150min, furnace exit temperature 1200~1220℃; 4) Rough rolling and finish rolling are performed to obtain strip steel. The exit temperature of rough rolling is 1050~1080℃, and the final rolling temperature of finish rolling is 880~915℃. 5) The strip is cooled to the coiling temperature by laminar flow and then coiled to obtain a steel coil. The coiling temperature at the head and tail of the steel coil is 700~709℃, and the coiling temperature in the middle of the steel coil is 650~690℃. The wave shape of the steel coil after leveling is: wave height ≤8mm, convexity 20~50μm, and local high point ≤8μm. 6) After the steel coil is cooled by air or water to ≤60℃, it is pickled and cold rolled continuously. The total reduction rate of cold rolling is 75~80% to obtain a substrate. The waviness of the substrate is: steepness ≤2% and waviness height ≤3mm. The continuous hot-dip plating step of the metal coating includes: When the metal coating is a high-alumina coating, the substrate enters an annealing furnace and is heated to 770-800°C at a heating rate of 2-10°C / s for homogenization. Then, it is rapidly cooled to 620-650°C at a cooling rate of 25-45°C / s, and then slowly cooled to 580-630°C at a cooling rate of 8-20°C / s. The annealed substrate is then placed in a zinc pot for continuous hot-dip galvanizing. When the metal coating is a pure zinc coating, the substrate enters an annealing furnace and is heated to 770-800°C at a heating rate of 2-6°C / s and held at that temperature. Then, it is rapidly cooled to 465-485°C at a cooling rate of 28-50°C / s. The annealed substrate is then placed in a zinc pot for continuous hot-dip galvanizing.

4. The production process of non-cut-corrosion-resistant color-coated steel sheet for curtain walls according to claim 3, characterized in that, When the metal coating is a high-aluminum coating, the continuous hot-dip plating steps include: 1) The substrate is placed in the annealing furnace and heated to 770-800°C at a heating rate of 2-10°C / s for homogenization, while controlling the furnace pressure at 20-80Pa. Then, it is rapidly cooled to 620-650°C at a cooling rate of 25-45°C / s, while controlling the dew point of the rapid cooling section to be <-20°C. Subsequently, it is slowly cooled to 580-630°C at a cooling rate of 8-20°C / s, while controlling the hydrogen volume percentage in the furnace nose to be 10-30%. 2) After annealing, the substrate is placed in a zinc pot for continuous hot-dip galvanizing. The temperature of the galvanizing solution in the zinc pot is 590~600℃. 3) After the hot-dip galvanized steel sheet exits the zinc pot, it passes through an air knife. The air knife height is controlled at 180~400mm, the air knife distance is 5~15mm, and the air knife angle is 0~-5°. 4) The steel plate after the air knife is rapidly cooled to ≤280℃ at a cooling rate of 10~23℃ / s, and then surface-finished with a finishing elongation of 1.0~1.2%.

5. The production process of non-cut-corrosion-resistant color-coated steel sheet for curtain walls according to claim 3, characterized in that, When the metal coating is a pure zinc coating, the continuous hot-dip galvanizing steps include: 1) The substrate is placed in an annealing furnace and heated to 770-800°C at a heating rate of 2-6°C / s and held at that temperature. Then it is rapidly cooled to 465-485°C at a cooling rate of 28-50°C / s. 2) After annealing, the substrate is placed in a zinc pot for continuous hot-dip galvanizing. The temperature of the galvanizing solution in the zinc pot is 455~465℃. 3) After the hot-dip galvanized steel sheet exits the zinc pot, it passes through an air knife. The air knife height is controlled at 200~700mm, the air knife distance at 7~16mm, and the air knife pressure at 60~400mbar. 4) The steel plate after the air knife is rapidly cooled to ≤200℃ at a cooling rate of 5~30℃ / s, and then surface-finished with a finishing elongation of 1.0~1.2%.

6. The production process of non-cut-corrosion-resistant color-coated steel sheet for curtain walls according to claim 3, characterized in that, The coating application steps include: 1) Clean the surface of the steel plate after continuous hot-dip galvanizing. The temperature of the cleaning solution should be 35~40℃. 2) Perform initial coating and fine coating, with a material roller pressure of 1780~1820Kg and a coating roller pressure of 100~300Kg; 3) The coating is cured in a curing oven at a temperature of 250~350℃ to obtain a color-coated steel sheet.

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