Low-carbon-emission corrosion-resistant thermoforming photovoltaic support and preparation method thereof

Abstract

The invention relates to a low-carbon-emission corrosion-resistant thermoforming photovoltaic support and a preparation method, and belongs to the technical field of high-strength steel preparation. The photovoltaic support comprises the following chemical components in percentage by mass: 0.17% to 0.30% of C, 0.2% to 1.0% of Si, 1.0% to 2.0% of Mn, less than or equal to 0.15% of P, less than or equal to 0.015% of S, 0.02% to 0.10% of Alt, 0.1% to 0.5% of Cu, 0.3% to 2.0% of Cr, 0.001% to 0.005% of B, 0.01% to 0.07% of Ti and a matrix element Fe. A component system with C-Si-Mn-B-Cu-Cr as main elements is adopted, the material strength can be improved through the hot forming process, in addition, corrosion-resistant elements such as Cu and Cr in the alloy are added, the corrosion resistance of the photovoltaic support is guaranteed, and the purpose of long-term corrosion resistance of the photovoltaic support can be achieved.

Description

Technical Field

[0001] The present application relates to the technical field of high-strength steel preparation, and in particular to a low-carbon emission, corrosion-resistant, thermoformed photovoltaic bracket and a preparation method thereof. Background Art

[0002] The photovoltaic industry is a green sector. By 2022, my country's cumulative installed photovoltaic capacity reached nearly 400 GW, a year-on-year increase of nearly 30%, demonstrating a booming growth trend. Photovoltaic mounting brackets are a key component in the industry, ensuring the safety of solar panels, especially in high winds. In theory, mounting brackets must withstand wind speeds of 216 km / h and at least a Category 13 typhoon, or 150 km / h. Furthermore, the service life of mounting brackets is generally required to be 25 years, making their structural safety and durability a key indicator.

[0003] Currently, there are two common types of photovoltaic brackets: aluminum alloy brackets and steel-coated brackets. Aluminum alloy brackets are lightweight but costly, typically 4-5 times the cost of steel. Coated brackets are typically pure zinc and zinc-aluminum-magnesium. These materials typically require a lengthy manufacturing process, resulting in high costs and carbon emissions. They are also cold-formed, generally resulting in lower strength. To ensure strength and rigidity, thicker materials are often used in designs. Summary of the Invention

[0004] The present application provides a low-carbon emission, corrosion-resistant thermoformed photovoltaic bracket and a preparation method thereof to solve the following technical problem: how to achieve corrosion resistance while ensuring strength.

[0005] In the first aspect, an embodiment of the present application provides a low-carbon emission, corrosion-resistant thermoformed photovoltaic bracket. The chemical composition of the photovoltaic bracket, measured by mass fraction, includes: C: 0.17%~0.30%, Si: 0.2%~1.0%, Mn: 1.0%~2.0%, P≤0.15%, S≤0.015%, Alt: 0.02%~0.10%, Cu: 0.1%~0.5%, Cr: 0.3%~2.0%, B: 0.001%~0.005%, Ti: 0.01%~0.07%, and matrix element Fe.

[0006] Optionally, the photovoltaic bracket meets at least one of the following properties: yield strength of 950MPa to 1150MPa, tensile strength of 1500MPa to 1800MPa, and elongation A50 of 7% to 15%.

[0007] Optionally, the microstructure of the photovoltaic support is martensite.

[0008] In a second aspect, the present application provides a method for preparing the photovoltaic bracket described in the first aspect, the method comprising:

[0009] Obtaining molten steel with the chemical composition;

[0010] The molten steel is sequentially subjected to continuous casting, continuous rolling and coiling to obtain a hot-rolled coil;

[0011] Slowly cooling the hot-rolled coil to obtain a hot-rolled steel plate;

[0012] The hot-rolled steel plate is sequentially pickled and hot stamped to obtain a photovoltaic bracket.

[0013] Optionally, the continuous casting and rolling includes continuous casting, soaking, rough rolling, induction heating and finishing rolling.

[0014] Optionally, the continuous casting speed is 4.0m / min to 6.0m / min, and the continuous casting billet thickness is 110mm to

[0015] 115mm.

[0016] Optionally, the soaking temperature is 1150°C to 1200°C.

[0017] Optionally, the inlet temperature of the rough rolling is ≥1150°C.

[0018] Optionally, the outlet temperature of the induction heating is 1050°C to 1200°C.

[0019] Optionally, the final rolling temperature of the finish rolling is 800°C to 860°C.

[0020] Optionally, the coiling temperature is 620°C to 730°C.

[0021] Optionally, the time interval between the coiling and the slow cooling is ≤30 min.

[0022] Optionally, the slow cooling time is 24 hours to 72 hours.

[0023] Optionally, the hot-rolled steel plate meets at least one of the following properties: yield strength of 450 MPa to 650 MPa, tensile strength of 500 MPa to 800 MPa, and elongation A50 of 10% to 30%.

[0024] Optionally, the microstructure of the hot-rolled steel plate is ferrite and pearlite.

[0025] Optionally, the thickness of the hot-rolled steel plate is 1.0 mm to 3.0 mm.

[0026] Optionally, the heating temperature of the hot stamping is 880° C. to 950° C., and the holding time of the hot stamping is 4 min to 8 min.

[0027] The above technical solution provided by the embodiment of the present application has the following advantages compared with the prior art:

[0028] The present invention provides a low-carbon emission, corrosion-resistant, thermoformed photovoltaic bracket. The chemical composition of the photovoltaic bracket, measured by mass, includes: C: 0.17% to 0.30%, Si: 0.2% to 1.0%, Mn: 1.0% to 2.0%, P ≤ 0.15%, S ≤ 0.015%, Alt: 0.02% to 0.10%, Cu: 0.1% to 0.5%, Cr: 0.3% to 2.0%, B: 0.001% to 0.005%, Ti: 0.01% to 0.07%, and the matrix element Fe. The C-Si-Mn-B-Cu-Cr composition system, primarily composed of elements, enhances material strength through the thermoforming process. Furthermore, the addition of corrosion-resistant elements such as Cu and Cr to the alloy ensures the corrosion resistance of the photovoltaic bracket, enabling the bracket to achieve long-term corrosion resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0030] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the embodiments or the description of the prior art. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0031] Figure 1 A schematic flow chart of a method for preparing a low-carbon emission, corrosion-resistant thermoformed photovoltaic bracket provided in an embodiment of the present application;

[0032] Figure 2 The microstructure diagram of the hot-rolled steel plate provided in Example 1 of the present application;

[0033] Figure 3 The edge microstructure diagram of the hot-rolled steel plate provided in Example 1 of the present application;

[0034] Figure 4 This is a microstructure diagram of the photovoltaic bracket provided in Example 1 of the present application. DETAILED DESCRIPTION

[0035] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0036] Various embodiments of the present application may be presented in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity and should not be understood as a rigid limitation on the scope of the present application; therefore, the range description should be considered to have specifically disclosed all possible sub-ranges and single numerical values ​​within the range; for example, the range description from 1 to 6 should be considered to have specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the range, such as 1, 2, 3, 4, 5 and 6, which apply regardless of the range; in addition, whenever a numerical range is indicated in this document, it is meant to include any cited number (fractional or integer) within the indicated range.

[0037] As used herein, the terms "including," "comprising," and the like mean "including but not limited to." Relational terms such as "first" and "second" are used solely to distinguish one entity or operation from another, and do not necessarily require or imply any actual relationship or order between these entities or operations. "And / or" describes the association relationship between associated objects, indicating that three relationships can exist. For example, "A and / or B" can mean: A exists alone, A and B exist at the same time, and B exists alone; where A and B can be singular or plural. "At least one" means one or more, "plurality" means two or more; "at least one," "at least one of the following" or similar expressions refers to any combination of these items, including any combination of single or plural items; for example, "at least one of a, b, or c" or "at least one of a, b, and c" can all mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can each be single or plural. "Parts" notation, such as parts by weight or parts by mass, indicates the proportional relationship between components. In this article, the parameters described by ratio should be understood as the first term of the proportional formula, in the order in which they are described, and the proportional figures should be understood as the second term. For example, if the mass ratio of substances A, B, and C is 1:2:3, then substances A, B, and C should correspond to the proportional figures in the proportional formula, in the order in which they are described: that is, the mass of substance A:the mass of substance B:the mass of substance C = 1:2:3.

[0038] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this article can be purchased from the market or prepared by existing methods.

[0039] In the first aspect, an embodiment of the present application provides a low-carbon emission, corrosion-resistant thermoformed photovoltaic bracket. The chemical composition of the photovoltaic bracket, measured by mass fraction, includes: C: 0.17%~0.30%, Si: 0.2%~1.0%, Mn: 1.0%~2.0%, P≤0.15%, S≤0.015%, Alt: 0.02%~0.10%, Cu: 0.1%~0.5%, Cr: 0.3%~2.0%, B: 0.001%~0.005%, Ti: 0.01%~0.07%, and matrix element Fe.

[0040] C is the core element that increases the strength and hardness of steel, and is also the basis for the formation of martensite structure; Si and Mn are commonly used alloying elements that can improve the plasticity and toughness of steel, and also help to improve hardenability.

[0041] B can significantly improve the hardenability of steel, making it easier to obtain a martensitic structure during the hot forming process, thereby improving the strength and hardness of the product. At the same time, B also helps to refine the grain size and enhance the material's resistance to intergranular corrosion. Cu and Cr are important alloying elements that further improve the corrosion resistance of steel. Cu can increase the corrosion resistance of steel in a reducing environment, while Cr can form a dense oxide film on the surface of the steel, effectively preventing further oxidative corrosion. The reasonable ratio of these two elements in the C-Si-Mn-B-Cu-Cr composition system makes the hot-formed photovoltaic bracket have excellent corrosion resistance in outdoor environments, able to withstand the test of various harsh climates.

[0042] Fe is a matrix element. The specific content / content range of Fe can be obtained by the upper and lower limit formula of the component, that is:

[0043] The sum of the percentages of the contents of each component in a composition should be equal to 100%, and the content ranges of several components should meet the following conditions: the upper limit of a component + the lower limit of other components ≤ 100; the lower limit of a component + the upper limit of other components ≥ 100.

[0044] In some embodiments, the photovoltaic support meets at least one of the following properties: a yield strength of 950 MPa to 1150 MPa, a tensile strength of 1500 MPa to 1800 MPa, and an elongation A50 of 7% to 15%.

[0045] In some embodiments, the microstructure of the photovoltaic support is martensite.

[0046] In this application, through the hot stamping process, the steel plate is rapidly cooled in the mold, and the austenitic structure is transformed into a martensitic structure with high strength and high hardness. This structural transformation significantly improves the mechanical properties of the steel, specifically manifested in a significant increase in tensile strength, yield strength and hardness.

[0047] Figure 1 A schematic flow chart of a method for preparing a low-carbon emission, corrosion-resistant thermoformed photovoltaic bracket provided in an embodiment of the present application.

[0048] See Figure 1 In a second aspect, the present application provides a method for preparing the photovoltaic bracket described in the first aspect, the method comprising:

[0049] S1, obtaining molten steel having the chemical composition;

[0050] S2, sequentially performing continuous casting, continuous rolling and coiling on the molten steel to obtain a hot-rolled coil;

[0051] In some embodiments, the continuous casting and rolling includes continuous casting, soaking, rough rolling, induction heating, and finishing rolling.

[0052] In some embodiments, the continuous casting speed is 4.0 m / min to 6.0 m / min, and the continuous casting slab thickness is 110 mm to 115 mm.

[0053] The pulling speed of continuous casting refers to the speed at which the billet is pulled out of the crystallizer during the continuous casting process. Different steel grades have different thermophysical properties and solidification characteristics, so the pulling speed needs to be adjusted according to the steel grade. In the embodiment of the present application, the pulling speed of continuous casting is 4.0m / min to 6.0m / min, which helps to uniformly cool and solidify the billet, reduce internal defects, and improve the quality of the billet. For example, the pulling speed of continuous casting can be 4.0m / min, 4.5m / min, 5.0m / min, 5.5m / min, 6.0m / min, etc. The billet thickness refers to the cross-sectional size of the billet produced during the continuous casting process. In the embodiment of the present application, the billet thickness is 110mm to 115mm. This thickness range can meet the needs of producing photovoltaic bracket products. For example, the billet thickness can be 110mm, 111mm, 112mm, 113mm, 114mm, 115mm, etc.

[0054] In some embodiments, the soaking temperature is 1150°C to 1200°C.

[0055] The main purpose of soaking treatment is to improve the temperature of the steel plate's edges and corners, and to increase temperature uniformity across the width of the steel plate. This facilitates control of the steel plate's shape, enhances the uniformity of its properties, and eliminates edge defects. A roller-hearth tunnel soaking furnace can be used for soaking treatment. For example, soaking temperatures can range from 1150°C, 1160°C, 1170°C, 1180°C, 1190°C, to 1200°C.

[0056] In some embodiments, the inlet temperature of the rough rolling is ≥1150°C.

[0057] A rough rolling inlet temperature of 1150°C or higher ensures full austenitization of the steel's internal structure, creating favorable conditions for plastic deformation during subsequent rough rolling. Austenite is a structural form of steel at higher temperatures, exhibiting excellent plasticity and deformability. For example, the rough rolling inlet temperature can be 1150°C, 1152°C, 1154°C, 1156°C, 1158°C, 1160°C, etc.

[0058] In some embodiments, the outlet temperature of the induction heating is 1050°C to 1200°C.

[0059] Induction heating is a highly efficient heating method that uses the principle of electromagnetic induction to generate eddy currents and heat within the steel, thereby achieving rapid heating. In the embodiments of this application, induction heating is used to supplementally heat the slab to ensure it reaches an appropriate temperature before finish rolling. For example, the outlet temperature of the induction heating can be 1050°C, 1080°C, 1110°C, 1140°C, 1170°C, 1200°C, etc.

[0060] In some embodiments, the final rolling temperature of the finish rolling is 800°C to 860°C.

[0061] Through finishing rolling, the slab can be further rolled to the required final thickness and width, and good surface quality and mechanical properties can be obtained. The final rolling temperature of finishing rolling is 800℃~860℃, which can ensure that the plate has good structure and performance after rolling. For example, the final rolling temperature of finishing rolling can be 800℃, 810℃, 820℃, 830℃, 840℃, 850℃, 860℃, etc. After finishing rolling, the plate is put into the heat preservation cover to reduce the temperature loss of the plate and ensure that it has a suitable temperature before coiling.

[0062] In some embodiments, the coiling temperature is 620°C to 730°C.

[0063] This temperature range can ensure that the sheet has good coil shape and internal quality after coiling. For example, the coiling temperature can be 620°C, 640°C, 660°C, 680°C, 700°C, 720°C, 730°C, etc.

[0064] S3, slowly cooling the hot-rolled coil to obtain a hot-rolled steel plate;

[0065] In some embodiments, the time interval between the coiling and the slow cooling is ≤30 min.

[0066] In some embodiments, the slow cooling time is 24 hours to 72 hours.

[0067] The high-temperature steel coil is quickly sent to slow cooling, and the time interval between coiling and the slow cooling is ≤30 minutes. This can avoid problems such as surface oxidation and decarburization caused by long-term exposure of the steel coil in an open environment. At the same time, it also helps to maintain a uniform temperature distribution inside the steel coil, creating favorable conditions for the subsequent slow cooling process. Exemplarily, the time interval between coiling and slow cooling can be 15 minutes, 18 minutes, 21 minutes, 24 minutes, 27 minutes, 30 minutes, etc. A slow cooling pit can be used in the slow cooling process. The main function of the slow cooling pit is to provide a relatively stable cooling environment so that the steel coil undergoes a favorable structural transformation during the slow cooling process. The slow cooling time is 24 hours to 72 hours, which can promote specific phase changes inside the steel. Exemplarily, the slow cooling time can be 24 hours, 34 hours, 44 hours, 54 hours, 64 hours, 72 hours, etc.

[0068] In some embodiments, the hot-rolled steel plate satisfies at least one of the following properties: a yield strength of 450 MPa to 650 MPa, a tensile strength of 500 MPa to 800 MPa, and an elongation A50 of 10% to 30%.

[0069] In some embodiments, the microstructure of the hot-rolled steel plate is ferrite and pearlite.

[0070] During the early stages of the hot stamping process, the hot-rolled steel sheet exhibits ease of processing due to its low yield strength and excellent plastic deformation capability. This low-strength state not only reduces die wear and energy consumption during the forming process, but also enables the material to more accurately replicate complex shapes. Furthermore, this characteristic helps avoid defects such as cracks during the forming process, thereby improving product yield and quality consistency.

[0071] In some embodiments, the hot-rolled steel plate has a thickness of 1.0 mm to 3.0 mm.

[0072] S4. The hot-rolled steel plate is pickled and hot-stamped in sequence to obtain a photovoltaic bracket.

[0073] After slow cooling, the steel plate is pickled. The main purpose of pickling is to remove impurities such as oxides and oil stains from the metal surface to improve its surface quality and corrosion resistance. In the embodiments of the present application, the pickling speed is ≥80m / min. This pickling speed not only prevents defects such as excessive corrosion or yellowing of the metal surface caused by prolonged immersion in acid, but also prevents the metal from being soaked for a long time during the pickling process, thereby reducing the amount of hydrogen adsorption and absorption, and reducing the risk of hydrogen embrittlement. This is especially true for hot-formed products, which are more sensitive to hydrogen embrittlement due to their higher strength and hardness.

[0074] In some embodiments, the heating temperature of the hot stamping is 880° C. to 950° C., and the holding time of the hot stamping is 4 min to 8 min.

[0075] The heating temperature for hot stamping is 880°C to 950°C. This temperature range allows the part material to reach an austenitic state, preparing for subsequent stamping. Heating can be carried out in a tunnel furnace or a box furnace. For example, the heating temperature for hot stamping can be 880°C, 890°C, 900°C, 910°C, 920°C, 930°C, 940°C, 950°C, etc. The holding time for hot stamping is 4 minutes to 8 minutes, which can ensure uniform temperature inside the part while avoiding the degradation of mechanical properties caused by excessively large austenite grains. For example, the holding time for hot stamping can be 4 minutes, 5 minutes, 6 minutes, 7 minutes, 8 minutes, etc. The heated and insulated steel plate is quickly transferred to a mold with a water channel for stamping. The water channel is designed to quickly cool the mold and steel plate during the stamping process to form a martensitic structure and improve the strength and hardness of the part.

[0076] This application adopts the idea of ​​hot forming to produce photovoltaic brackets. The composition adopts a component system with C-Si-Mn-B-Cu-Cr as the main elements. The advantage of low strength of steel plates before hot forming is used for complex forming such as pipe making. High strength is obtained after hot forming, and the tensile strength is ≥1500MPa. The purpose of weight reduction is achieved while ensuring strength and rigidity. A short process production line is adopted in the manufacturing process to achieve lower carbon emissions in the production process. The photovoltaic bracket is bare-mounted, and the addition of corrosion-resistant elements ensures a service life of 25 years.

[0077] The product prepared by the method for preparing the low-carbon emission corrosion-resistant thermoformed photovoltaic bracket is the above-mentioned low-carbon emission corrosion-resistant thermoformed photovoltaic bracket. Since the method for preparing the low-carbon emission corrosion-resistant thermoformed photovoltaic bracket adopts part or all of the technical solutions of the low-carbon emission corrosion-resistant thermoformed photovoltaic bracket embodiment, it at least has all the beneficial effects brought by the technical solutions of the low-carbon emission corrosion-resistant thermoformed photovoltaic bracket embodiment, which will not be repeated here one by one.

[0078] The present application is further described below with reference to specific examples. Experimental methods in the following examples where specific conditions are not specified are generally measured in accordance with national / industry standards. If there are no corresponding national / industry standards, the methods are carried out in accordance with commonly used international standards, conventional conditions, or conditions recommended by the manufacturer.

[0079] The chemical compositions of the molten steels of the examples and comparative examples are shown in Table 1.

[0080] Table 1 Chemical composition of molten steel of embodiment and comparative example (wt%)

[0081] Group C Si Mn P S Alt Cu Cr B Ti Example 1 0.23 0.40 1.3 0.10 0.002 0.04 0.40 1.0 0.0030 0.050 Example 2 0.20 0.35 1.7 0.08 0.004 0.03 0.30 0.8 0.0025 0.040 Example 3 0.28 0.25 1.3 0.07 0.002 0.04 0.40 1.2 0.0027 0.050 Comparative Example 1 0.29 0.28 1.2 0.008 0.006 0.051 - 1.0 0.39 0.048 Comparative Example 2 0.20 0.35 1.7 0.08 0.004 0.03 0.30 0.15 0.0025 0.040

[0082] Note: “-” means the element is not added.

[0083] Example 1

[0084] Based on the chemical composition of the molten steel in Example 1, continuous casting was carried out with a continuous casting speed of 4.7m / min and a slab thickness of 115mm. The slab was put into a roller bottom tunnel soaking furnace for soaking treatment, and the soaking temperature was controlled at 1190°C. The rough rolling inlet temperature was 1160°C. The slab underwent 3 rough rolling passes and was heated by induction heating equipment. The induction heating outlet temperature was controlled at 1180°C. The finishing rolling was carried out in 5 passes, and the final rolling temperature was controlled at 845°C. After finishing rolling, an insulation cover was put on the roller table, and the coiling temperature was 680°C. It took 15 minutes for the steel coil to be transported from the line to the insulation pit, and it stayed in the insulation pit for 48 hours. The hot coil was pickled at a pickling speed of 100m / min. The thickness of the steel coil after pickling was 1.2mm, and the oil coating amount of the steel coil was 1800mg / m 2 The pickled sheet is stripped and formed into square tubes with a side length of 60mm x 80mm. The tubes are then hot stamped at 890°C for 5 minutes in a mold with a water channel. The hot-formed parts are then connected and assembled.

[0085] Example 2

[0086] Based on the chemical composition of the molten steel in Example 2, continuous casting was carried out with a continuous casting speed of 4.6m / min and a slab thickness of 115mm. The slab was put into a roller bottom tunnel soaking furnace for soaking treatment, and the soaking temperature was controlled at 1185°C. The rough rolling inlet temperature was 1160°C. The slab underwent 3 rough rolling passes and was heated by induction heating equipment. The induction heating outlet temperature was controlled at 1170°C. The finishing rolling was carried out in 5 passes, and the final rolling temperature was controlled at 840°C. After finishing rolling, an insulation cover was put on the roller table, and the coiling temperature was 678°C. It took 20 minutes for the steel coil to be transported from the line to the insulation pit, and it stayed in the insulation pit for 48 hours. The hot coil was pickled at a pickling speed of 110m / min. The thickness of the steel coil after pickling was 1.5mm, and the oil coating amount of the steel coil was 1800mg / m 2The pickled sheet is then stripped and formed into square tubes with a side length of 20mm x 80mm. The tubes are then hot stamped at 900°C for 4.5 minutes in a mold with a water channel. The hot-formed parts are then connected and assembled.

[0087] Example 3

[0088] Based on the chemical composition of the molten steel in Example 3, continuous casting was carried out with a continuous casting speed of 4.8m / min and a slab thickness of 110mm. The slab was put into a roller bottom tunnel soaking furnace for soaking treatment, and the soaking temperature was controlled at 1190°C. The rough rolling inlet temperature was 1160°C. The slab underwent 3 rough rolling passes and was heated by induction heating equipment. The induction heating outlet temperature was controlled at 1175°C. The finishing rolling was carried out in 5 passes, and the final rolling temperature was controlled at 836°C. After finishing rolling, an insulation cover was put on the roller table, and the coiling temperature was 671°C. It took 22 minutes for the steel coil to be transported from the line to the insulation pit, and it stayed in the insulation pit for 36 hours. The hot coil was pickled at a pickling speed of 120m / min. The thickness of the steel coil after pickling was 2.0mm, and the oil coating amount of the steel coil was 1600mg / m 2 The pickled sheet is then stripped and formed into square tubes with a side length of 60mm x 80mm. The tubes are then hot stamped at 930°C for 4 minutes in a mold with a water channel. The hot-formed parts are then connected and assembled.

[0089] Comparative Example 1

[0090] Based on the chemical composition of the molten steel in comparative example 1, continuous casting was carried out with a continuous casting speed of 4.7m / min and a slab thickness of 115mm. The slab was put into a roller bottom tunnel soaking furnace for soaking treatment, and the soaking temperature was controlled at 1190°C. The rough rolling inlet temperature was 1160°C. The slab underwent 3 rough rolling passes and was heated by induction heating equipment. The induction heating outlet temperature was controlled at 1180°C. The finishing rolling was carried out in 5 passes, and the final rolling temperature was controlled at 845°C. After finishing rolling, an insulation cover was put on the roller, and the coiling temperature was 680°C. It took 15 minutes for the steel coil to be transported from the line to the insulation pit, and it stayed in the insulation pit for 48 hours. The hot coil was pickled at a pickling speed of 100m / min. The thickness of the steel coil after pickling was 1.2mm, and the oil coating amount of the steel coil was 1800mg / m 2 The pickled sheet is stripped and formed into square tubes with a side length of 60mm x 80mm. The tubes are then hot stamped at 890°C for 5 minutes in a mold with a water channel. The hot-formed parts are then connected and assembled.

[0091] Comparative Example 2

[0092] Based on the chemical composition of the molten steel in Comparative Example 2, continuous casting was carried out with a continuous casting speed of 4.6m / min and a slab thickness of 115mm. The slab was put into a roller bottom tunnel soaking furnace for soaking treatment, and the soaking temperature was controlled at 1185°C. The rough rolling inlet temperature was 1160°C. The slab underwent 3 rough rolling passes and was heated by induction heating equipment. The induction heating outlet temperature was controlled at 1170°C. The finishing rolling was carried out in 5 passes, and the final rolling temperature was controlled at 840°C. After finishing rolling, an insulation cover was put on the roller, and the coiling temperature was 678°C. It took 20 minutes for the steel coil to be transported from the line to the insulation pit, and it stayed in the insulation pit for 48 hours. The hot coil was pickled at a pickling speed of 110m / min. The thickness of the steel coil after pickling was 1.5mm, and the oil coating amount of the steel coil was 1800mg / m 2 The pickled sheet is then stripped and formed into square tubes with a side length of 20mm x 80mm. The tubes are then hot stamped at 900°C for 4.5 minutes in a mold with a water channel. The hot-formed parts are then connected and assembled.

[0093] The mechanical properties of the examples and comparative examples are shown in Table 2.

[0094] Table 2

[0095]

[0096] It can be seen from the examples and comparative examples that the addition of elements Cu and Cr ensures the corrosion resistance of the photovoltaic bracket.

[0097] Attachment Figure 2-4 Detailed description:

[0098] Figure 2 The microstructure diagram of the hot-rolled steel plate provided in Example 1 of the present application; Figure 2 As shown, the structure contains ferrite and pearlite.

[0099] Figure 3 The edge microstructure diagram of the hot-rolled steel plate provided in Example 1 of the present application; Figure 3 As shown, there are no cracks on the edges, indicating that there is no intergranular oxidation in the hot-rolled plates produced.

[0100] Figure 4 The microstructure diagram of the photovoltaic bracket provided in Example 1 of the present application; Figure 4 As shown, the structure is martensite.

[0101] One or more technical solutions in the embodiments of the present invention may have at least the following technical effects or advantages:

[0102] Compared with currently commercial aluminum alloy brackets and steel coating products, the embodiments of the present invention have the following advantages:

[0103] (1) Lower cost, while aluminum alloy products and plated products are more expensive;

[0104] (2) Lower carbon emissions: The product of the present invention has a shorter manufacturing process. After being produced on a continuous casting and rolling production line, the thickness of the hot-rolled product can reach 1.0 mm, covering the thickness specifications of the current cold-rolled coating products of photovoltaic brackets. In addition, the present invention adopts a hot stamping forming process, and the tensile strength after hot stamping is ≥1500 MPa. The required steel plate thickness is thinner, and less steel is used while ensuring strength and rigidity.

[0105] (3) Safety: The present invention has higher strength and ensures safety while reducing weight. The present invention ensures a service life of ≥25 years in the bare case by adding alloy elements.

[0106] The foregoing is merely a list of specific embodiments of the present application, intended to enable those skilled in the art to understand or implement the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application is not limited to the embodiments shown herein, but rather is intended to conform to the broadest scope consistent with the principles and novel features claimed herein.

Claims

1. A low-carbon emission, corrosion-resistant thermoformed photovoltaic bracket, wherein the chemical composition of the photovoltaic bracket comprises, by mass fraction: C： 0.17%~0.30%, Si: 0.2%~1.0%, Mn: 1.0%~2.0%, P≤0.15%, S≤0.015%, Alt: 0.02%~0.10%, Cu: 0.1%~0.5%, Cr: 0.3%~2.0%, B: 0.001%~0.005%, Ti: 0.01%~0.07%, and matrix element Fe.

2. The photovoltaic bracket according to claim 1, characterized in that: The photovoltaic bracket meets at least one of the following properties: a yield strength of 950 MPa to 1150 MPa, a tensile strength of 1500 MPa to 1800 MPa, and an elongation A50 of 7% to 15%.

3. The photovoltaic bracket according to claim 1, characterized in that: The microstructure of the photovoltaic support is martensite.

4. A method for preparing the photovoltaic bracket according to any one of claims 1 to 3, comprising: Obtaining molten steel with the chemical composition; The molten steel is sequentially subjected to continuous casting, continuous rolling and coiling to obtain a hot-rolled coil; Slowly cooling the hot-rolled coil to obtain a hot-rolled steel plate; The hot-rolled steel plate is sequentially pickled and hot stamped to obtain a photovoltaic bracket.

5. The method according to claim 4, characterized in that The continuous casting and rolling process includes continuous casting, soaking, rough rolling, induction heating and finishing rolling.

6. The method according to claim 5, characterized in that The continuous casting speed is 4.0m / min to 6.0m / min, and the continuous casting billet thickness is 110mm to 115mm; and / or, The soaking temperature is 1150° C. to 1200° C.; and / or, The inlet temperature of the rough rolling is ≥1150°C; and / or, The outlet temperature of the induction heating is 1050°C to 1200°C; and / or, The final rolling temperature of the finishing rolling is 800°C to 860°C.

7. The method according to claim 4, characterized in that The coiling temperature is 620°C to 730°C; and / or, The time interval between the coiling and the slow cooling is ≤30 min; and / or, The slow cooling time is 24h to 72h.

8. The method according to claim 4, characterized in that The hot-rolled steel plate meets at least one of the following properties: a yield strength of 450 MPa to 650 MPa, a tensile strength of 500 MPa to 800 MPa, and an elongation A50 of 10% to 30%.

9. The method according to claim 4, characterized in that The microstructure of the hot-rolled steel plate is ferrite and pearlite; and / or, The thickness of the hot-rolled steel plate is 1.0 mm to 3.0 mm.

10. The method according to claim 4, characterized in that The heating temperature of the hot stamping is 880° C. to 950° C., and the holding time of the hot stamping is 4 min to 8 min.

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