High-strength, wear-resistant, and corrosion-resistant steel for photovoltaic supports with excellent plasticity and manufacturing method thereof

Abstract

The present invention discloses a high-strength, wear-resistant, and corrosion-resistant steel for photovoltaic brackets with excellent plasticity and a manufacturing method thereof. The steel comprises chemical compositions of C 0.074-0.094%, Si 0.39-0.57%, Mn 0.91-1.16%, P ≤ 0.016%, S ≤ 0.006%, Cr 1.03-1.27%, Cu 0.16-0.24%, Sb 0.106-0.126%, Ti 0.051-0.071%, Mo 0.20-0.32%, Ce 0.0168-0.0188%, Al 0.050-0.073%, and a Si / Mo ratio of 1.2-2.9. The manufacturing method comprises smelting, slab continuous casting, slab heating, rolling, laminar cooling, and coiling. The steel has a Rel value of 633-655 MPa, an Rm value of 812-842 MPa, an A value greater than 34%, a yield strength ratio of 0.77-0.79, a surface hardness of 220-224 HBW, a wear rate of 28.1-29.2% relative to Q345B, and a corrosion rate of 29.74-32.48%. This steel exhibits excellent plasticity and formability, as well as excellent wear resistance and atmospheric corrosion resistance, resolving the issues of insufficient plasticity and wear resistance in existing photovoltaic support steels.

Description

Technical Field

[0001] The present invention belongs to the field of corrosion-resistant steel for photovoltaic supports, and relates to high-strength, wear-resistant, and corrosion-resistant steel for photovoltaic supports with excellent plasticity and a manufacturing method thereof. Background Art

[0002] As a crucial support device in photovoltaic power generation systems, photovoltaic brackets' performance directly impacts the lifespan of PV power plants. Long-term exposure to the atmosphere can cause varying degrees of corrosion, impacting their durability. PV power plants built in deserts and windswept areas are particularly vulnerable to the abrasive effects of wind and sand. Therefore, the material's corrosion and wear resistance are crucial considerations. Furthermore, photovoltaic brackets undergo a complex series of deformation processes during manufacturing, requiring materials with excellent plasticity and formability to prevent bending and cracking during these processes.

[0003] Currently, most materials used to manufacture photovoltaic brackets are galvanized after processing low-grade steel coils or lightweight profiles. However, the production process of hot-dip galvanized products is complex, and the galvanizing process is highly polluting to the environment. Weathering steel, due to its inherent corrosion resistance, is an ideal material for manufacturing photovoltaic brackets. However, domestic production of weathering steel for photovoltaic brackets often only considers its atmospheric corrosion resistance and ignores the wear resistance required for the bracket's service life. At the same time, as weathering steel for photovoltaic brackets develops towards thinner gauges and higher strength, the requirements for its ductility and formability are gradually increasing. Therefore, the development of a high-strength steel for photovoltaic brackets that combines high corrosion resistance, high wear resistance, and excellent formability is an urgent need for the development of the photovoltaic industry.

[0004] Prior to the present invention,

[0005] The invention patent, "A high-strength weathering steel for photovoltaic brackets and its preparation method," with publication number CN 115786822 B, contains the following components: C: 0.05% to 0.07%, Si: 0.30% to 0.40%, Mn: 0.70% to 1.00%, P: ≤0.025%, S: ≤0.005%, Als: 0.020% to 0.040%, Cu: 0.25% to 0.35%, Cr: 0.55% to 0.75%, Ni: 0.15% to 0.30%, Nb: 0.030% to 0.050%, Ti: 0.070% to 0.090%, N: ≤0.005%, Ca: 0.0005% to 0.0020%, and the remainder is Fe and impurities. This invention incorporates precious metal Ni, which has a high content, and the addition of Ni will increase costs. Moreover, the invention does not mention the specific impact on wear resistance, and the corrosion resistance is only predicted using the theoretical parameter I. The specific corrosion resistance index of the invented steel is not explained, so its actual wear resistance and corrosion resistance are unknown.

[0006] The invention patent, "A Low-Cost 650MPa-Grade Antimony-Containing Weathering Steel for Photovoltaic Brackets and Its Preparation Method," with publication number CN 116121668 A, contains the following components: C: ≤0.08%, Si: 0.35%-0.50%, Mn: 0.40%-0.60%, P: 0.08%-0.12%, S: ≤0.010%, Cu: 0.25%-0.40%, Cr: 0.75%-1.00%, Ti: 0.065%-0.105%, N: ≤0.0050%, Sb: 0.05%-0.07%, with the remainder being Fe and impurities. The high Cu content in this invention not only increases costs but also causes cracks at the edges of the steel. While this invention improves the corrosion resistance of the steel by adding P, the addition of P can easily lead to elemental segregation, severely reducing the steel's plasticity and adversely affecting deformation during later processing of the photovoltaic bracket. In addition, the invention does not mention the specific impact on wear resistance, and the corrosion resistance is only predicted using the theoretical parameter I. The specific corrosion resistance indicators of the invented steel are not explained, so its actual wear resistance and corrosion resistance are unknown.

[0007] The invention patent "A corrosion-resistant, wear-resistant steel plate and its preparation method" with publication number CN112159934A has the following composition: C: 0.14%~0.22%, Si: 0.10%~1.00%, Mn: 0.1%~1.0%, P: less than 0.015%, S: less than 0.005%, Cr: 3.00%~6.00%, Ni: 0.00%~1.50%, Mo: 0.00%~0.80%, Als: 0.02%~0.06%, B: 0.0008%~0.005%, Ca: 0.0015%~0.0040%, where Ca / S≥1, and the rest is Fe and impurities. The Cr element added in this invention has a high content, which increases the difficulty of smelting; and this invention improves the corrosion resistance by adding Cr, but does not clarify the corrosion resistance index, and the corrosion environment targeted is acidic conditions; this invention obtains a hard phase martensitic structure through a quenching + tempering process to improve the wear resistance of the invention steel, and the process flow is relatively complicated.

[0008] The invention patent "Coal-water wear and corrosion-resistant steel plate for railway coal transport vehicles and its manufacturing method" with publication number CN107653423B has the following composition: C: 0.01%~0.15%, Si: 0.10%~0.50%, Mn: 0.20%~1.0%, P≤0.020%, S≤0.010%, Cu: 0.20%~0.60%, Ni: 0.50%~1.5%, Cr: 0.20%~2.0%, Sb: 0.030%~0.10%, Mo: 0%~0.25%, Nb: 0%~0.05%, V: 0%~0.05%, Ti: 0%~0.10%, B: 0%~0.005%, and the rest is Fe and impurities; and C, Cr, and Ni must satisfy 1.6%≤12C+Cr / Ni≤2.8%. This invention controls the C, Cr, and Ni contents to meet the requirement of 1.6% ≤ 12C + Cr / Ni ≤ 2.8%, resulting in a wear and corrosion rate of 20% to 30% relative to Q450NQR1. However, the invention adds a large number of precious metal elements such as Cu, Ni, Nb, and V, and their contents, which will significantly increase production costs and hinder its promotion. The invention does not describe the corrosion resistance of the product, and the wear and corrosion resistance of the steel in this invention is targeted at its performance in a coal-water corrosive environment, which is very different from the corrosive environment of photovoltaic brackets. Summary of the Invention

[0009] The present invention aims to provide a high-strength, wear-resistant, and corrosion-resistant steel for photovoltaic brackets with excellent plasticity and a method for manufacturing the same. This high-strength steel for photovoltaic brackets not only exhibits excellent plasticity and formability, but also possesses excellent wear resistance and atmospheric corrosion resistance, resolving the existing problems of thin-gauge, high-strength photovoltaic bracket steels with insufficient plasticity and wear resistance.

[0010] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0011] The present invention proposes a high-strength, wear-resistant and corrosion-resistant steel for a photovoltaic bracket with excellent plasticity. The chemical composition is as follows by weight: C: 0.074% to 0.094%, Si: 0.39% to 0.57%, Mn: 0.91% to 1.16%, P: ≤0.016%, S: ≤0.006%, Cr: 1.03% to 1.27%, Cu: 0.16% to 0.24%, Sb: 0.106% to 0.126%, Ti: 0.051% to 0.071%, Mo: 0.20% to 0.32%, Ce: 0.0168% to 0.0188%, Als: 0.050% to 0.073%, wherein Si / Mo is controlled at 1.2 to 2.9, and the balance is Fe and unavoidable impurities.

[0012] The present invention selects the above alloying element types and contents because:

[0013] C: A key element in ensuring material strength and hardness. In this invention, C primarily enhances the strength of steel plates through solid solution strengthening and precipitation strengthening. When added in combination with Mo, it forms a hard phase, Mo2C3, within the grains, enhancing the steel's hardness and wear resistance. However, excessive C can degrade the steel's plasticity and formability. In this invention, the C content is limited to 0.074% to 0.094%.

[0014] Si: One of the key elements for improving corrosion resistance, strength, and hardness. Si easily accumulates on the surface of steel sheets, forming a dense, matrix-bound SiO2 protective oxide film on the product surface that effectively inhibits the penetration of corrosive media. When added in combination with Mo, it reacts with free Mo in the steel to form Mo2Si3 hard-phase particles. By controlling the finishing and coiling temperatures, micron-sized (40-70 μm) hard-phase Mo2Si3 particles can be dispersed and precipitated near grain boundaries or within grains, effectively improving the steel's hardness and wear resistance. However, excessive Si content not only negatively impacts surface quality but also degrades steel performance by forming large Mo2Si3 particles. Therefore, the present invention limits the Si content to 0.39% to 0.57%. Furthermore, the Si and Mo contents determine the Si-Mo type and the state of the precipitated particles. To obtain more dispersed precipitated particles, the Si / Mo ratio is controlled between 1.2 and 2.9.

[0015] Mn: One of the main strengthening elements in steel, it can improve the strength of steel plates through solid solution strengthening. At the same time, Mn in the present invention, as an important austenitizing stabilizing element, can expand the austenite phase region, improve the stability of retained austenite in steel, and improve the plasticity of the material. Therefore, in order to ensure and improve the strength and plasticity of the material, the Mn content of the present invention is set to 0.91% to 1.16%.

[0016] P: Although it is one of the alloying elements that plays a role in solid solution strengthening and significantly improves corrosion resistance, when its content is too high, it is easy to segregate at the grain boundaries and reduce the welding performance, plasticity and toughness of the steel plate. In the steel of the present invention, the content of P is controlled below 0.016%.

[0017] S: A harmful impurity element in steel, S easily forms defects such as segregation and inclusions, which can deteriorate the impact toughness and hot workability of the steel plate. However, controlling the S content too low increases smelting costs. Therefore, in the present invention, the S content should be controlled below 0.006%.

[0018] Cr: It mainly improves the strength of steel by solid solution strengthening, and this element can significantly increase the tensile limit of steel. Its contribution to improving tensile strength is higher than that of yield strength, and it can effectively reduce the yield strength ratio of the material. At the same time, this element is the main corrosion-resistant element, and is often enriched in the rust layer. It not only easily forms a dense oxide film on the surface of the steel plate, but also forms a dense Cr-Cu compound protective rust layer on the surface of the substrate with the Cu element, which can significantly inhibit the penetration of corrosive media, thereby achieving a double-layer corrosion resistance effect, and can replace part of the corrosion resistance of Cu. However, when its content is too high, it will not only deteriorate the welding performance of the steel plate but also increase the difficulty of smelting. Therefore, the Cr content in the present invention is controlled to be 1.03% to 1.27%.

[0019] Cu: One of the important corrosion-resistant elements. This element is often enriched in the rust layer, which can effectively improve the permeability of the corrosive medium, and it is easy to form a dense Cu-P compound protective rust layer with the P element on the surface of the substrate, which can further inhibit the penetration of the corrosive medium. At the same time, this element is often dissolved in Fe to form a substitutional solid solution, which has a solid solution strengthening effect, thereby improving the strength of the steel plate. However, when the Cu content is too high, it not only increases the cost, but also easily causes "copper brittleness" defects on the edge of the steel plate in the absence of Ni elements. Therefore, the present invention avoids the occurrence of "copper brittleness" defects by adding rare earth Ce elements to disperse them and combining them with a heating process. The present invention limits its content range to 0.16% to 0.24%.

[0020] Ti: A strong carbon and nitrogen compound former, it's a key element in improving strength. During steel plate heating, it often forms Ti-N compounds with nitrogen, inhibiting austenite grain growth and achieving grain refinement. It also forms fine carbides and nitrides or carbonitrides with carbon and nitrogen, which then precipitate fine compounds during steel plate cooling and coiling, contributing to precipitation strengthening. The present invention limits the Ti content to 0.051% to 0.071%.

[0021] Sb: An effective element for improving the corrosion and wear resistance of steel sheets. This element readily forms a dense oxide film on the substrate surface, enhancing the steel sheet's passivation capabilities. By combining it with P, Cu, and Cr, it synergistically concentrates within the rust layer, forming a dense, matrix-bound Sb-P-Cu-Cr composite protective rust layer that further impedes the intrusion of corrosive media. Furthermore, the Sb3O4 hard phase formed within the substrate precipitates along grain boundaries during cooling and coiling, further enhancing the steel sheet's wear resistance. In the present invention, the Sb content is controlled to be 0.106% to 0.126%.

[0022] Mo: There are three main forms of existence in steel. One part dissolves in iron to form a substitutional solid solution, which improves the yield strength of the steel; one part forms a Mo-C hard phase Mo2C3 with the free C in the steel, which can significantly improve the hardness and wear resistance of the steel; and a small part segregates at the grain boundaries; when Mo is added in combination with the rare earth Ce, the strong affinity of Ce can reduce the segregation of Mo at the grain boundaries. Ce promotes the uniform precipitation of the Mo2C3 hard phase and inhibits its aggregation and growth, which can further improve the wear resistance of the steel plate; especially when added in combination with Si, it can form Mo2Si3 hard phase particles with the free Si in the steel. By controlling the final rolling temperature and the coiling temperature, micron-sized (40-70μm) hard phase Mo2Si3 particles will be dispersed and precipitated near the grain boundaries or inside the grains, greatly improving the hardness and wear resistance of the steel. In order to better exert the synergistic wear-resistant effect of Si and Mo, the present invention limits the Si / Mo ratio to 1.2-2.9. However, when the Mo content is too high, the degree of segregation at the grain boundary will increase, and the plasticity, toughness and welding performance of the steel will be deteriorated. The Mo content is controlled at 0.20%-0.32%.

[0023] AlS: An important deoxidizing element, it purifies the molten steel into a low-oxygen environment. This prevents the rare earth from reacting with excess oxygen in the molten steel, allowing the rare earth to fully utilize its solid solution properties. This element's primary function is to complement the addition of rare earth. The present invention limits its content to 0.050% to 0.073%.

[0024] Ce: (1) As an effective deoxidizing and desulfurizing element, it can purify the molten steel and improve the mechanical properties of the product; it can change the shape and type of inclusions, reduce the potential difference between the inclusions and the matrix, reduce the tendency of electrochemical corrosion caused by inclusions, and effectively improve the corrosion resistance of the steel plate; (2) It has the function of dispersing Cu, which can avoid the occurrence of "copper brittleness" defects on the one hand, and improve the utilization rate of Cu on the other hand, thereby increasing the ratio of the protective phase α-FeOOH / γ-FeOOH, improving the stability of the rust layer, and further improving the corrosion resistance of the steel plate; (3) It improves the segregation of Mo, promotes the uniform precipitation of the hard phases Mo2C3 and Mo2Si3, and inhibits the aggregation and growth of the phases, thereby improving the wear resistance of the steel plate; (4) The addition of RE elements helps to inhibit the decomposition of retained austenite and the precipitation of carbides, which can significantly improve the plasticity and forming properties of the steel plate, and facilitate the later processing of the material such as bending. The present invention limits its range to 0.0168% to 0.0188%.

[0025] The present invention also provides a method for manufacturing high-strength, wear-resistant, and corrosion-resistant steel for photovoltaic brackets with excellent plasticity. The method comprises pre-desulfurization of molten iron, top and bottom blowing of a converter, LF refining outside the furnace, continuous casting of slabs, heating of ingots, hot rolling, laminar cooling, and coiling to obtain wear-resistant and atmospheric corrosion-resistant steel containing the above-mentioned chemical components, and specifically includes the following contents.

[0026] Smelting: First, the molten iron is subjected to desulfurization pretreatment so that the S content in the molten iron after desulfurization is ≤0.002%. A furnace top and bottom composite blowing process is adopted, and the converter tapping temperature is 1646-1661°C. Then the molten iron is fed into the LF furnace for heating and composition fine-tuning, and then Si-Ca wire feeding treatment is carried out to further reduce the O and S contents to ensure that the free O content in the steel should be controlled below 3.6ppm; 7-9 minutes before the end of the vacuum treatment in the LF furnace, 1.87-2.09kg / ton of steel of 20% Ce-Fe rare earth alloy is added to the LF furnace, and then argon weak blowing (argon flow rate 110-130NL / min, pressure 0.18-0.31MPa) is carried out with stirring, and the weak blowing time is 4.1-6.1min to ensure that the inclusions are fully floated and denatured.

[0027] Slab continuous casting: Molten steel is protected throughout the slab casting process using mold slag to prevent exposure to air. The thickness of the slabs ranges from 210 to 230 mm. Because the rare earth element Ce in the invention steel has a strong affinity for oxygen and sulfur, it easily forms a large number of rare earth inclusions with the steel, affecting the fluidity of the molten steel. Therefore, the casting speed is controlled at 1.32-1.52 m / min. To reduce centerline segregation of the slabs, the superheat is maintained between 20-23°C during casting. Electromagnetic stirring and dynamic soft reduction are also employed.

[0028] Ingot Heating: One of the primary methods used in this invention to improve steel plate strength is microalloying solid solution strengthening, particularly when Si and Mo are added in combination. To ensure sufficient solid solution of these alloying elements, the ingot is heated to 1270-1296°C. The steel of this invention is copper-containing steel, and Cu and Ni are typically added in combination to suppress the occurrence of "copper brittleness." However, to reduce costs, this invention avoids this "copper brittleness" defect by devising a rational heating process rather than adding the precious metal Ni. Therefore, in order to avoid the occurrence of "copper brittleness" defects caused by the precipitation of low-melting-point element Cu on the surface of the steel plate, the heating furnace atmosphere is set to a reducing atmosphere with an air-fuel ratio between 1.6 and 2.0. When the heating temperature is below 1105°C, slow heating is required, and the heating rate is controlled at 6.2-8.3°C / min to ensure uniform temperature inside and outside the billet; when the temperature is above 1105°C, rapid heating is required, and the heating rate is controlled at 16.5-18.5°C / min. Since the longer the heating time, the more conducive it is for Cu to diffuse along the austenite grain boundaries, and the more likely it is to produce "copper brittleness" defects, the furnace time is controlled to be ≤200min, preferably 172-195min, of which the holding time in the soaking section is 32-47min.

[0029] Rolling: The steel is subjected to temperature-controlled rolling in two stages: roughing and finishing. Roughing utilizes high temperature and high reduction. The final roughing temperature is 1104-1139°C, and the cumulative reduction during the roughing stage is 82.1%-85.3%. This high cumulative reduction not only closes existing defects in the ingot but also increases deformation, creating more dislocations and thereby enhancing the material's strength through dislocation strengthening. The start temperature for finishing rolling is 1085-1113°C. To eliminate the negative effects of dislocation strengthening on plasticity during the roughing stage and ensure sufficient precipitation of the Mo2C3 and Mo2Si3 hard phases, a higher final rolling temperature is established, ranging from 932-948°C. To ensure the flatness and precision of the finished steel plate, the reduction during the final finishing pass is controlled at 15.8%-16.7%. Throughout the rolling process, the target crown is maintained at 34-41μm.

[0030] After finishing rolling, laminar cooling is performed in a two-stage cooling method. In the first stage, the steel is cooled to 746-766°C (this temperature range belongs to the ferrite transformation region) at a cooling rate of 18-25°C / s, followed by air cooling for 8-10s. During this stage, sufficient soft ferrite structure is obtained and the Mo2C3 and Mo2Si3 phases are inoculated, making them easy to precipitate and grow, thereby ensuring the plasticity and wear resistance of the steel plate. Subsequently, the steel is cooled in the second stage at a cooling rate of 29-39°C / s to 594-614°C for coiling. During this stage, sufficient hard bainite is generated to ensure the strength performance of the product. This coiling temperature also has a good effect on refining the grains and inhibiting the coarsening of the Mo2C3 and Mo2Si3 precipitation phases.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] Through precise control of the composition and tissue proportions, the wear-resistant and corrosion-resistant steel coil for 1.8-4.0mm photovoltaic brackets produced using the above chemical composition and rolling process has a yield strength of 633-655MPa, a tensile strength of 812-842MPa, an elongation of >34%, and a yield strength ratio of 0.77-0.79, with excellent plasticity and forming properties; through the control of hard phase precipitates and their sizes, the surface hardness of the invented steel is 220-224HBW, and the wear rate relative to Q345B is 28.1%-29.2%; through the reasonable combination of corrosion-resistant elements, in the rapid corrosion evaluation test simulating a C4-grade atmospheric environment, the corrosion rate of the invented steel relative to Q345B is 29.74%-32.48%. The present invention overcomes the shortcomings of the existing technology and enables the production of thin-gauge, high-strength weathering steel for photovoltaic brackets to have both excellent plasticity and forming properties, as well as excellent wear resistance and atmospheric corrosion resistance, ensuring that the photovoltaic brackets will not have defects such as cracks during bending and deformation, and will be safe and durable when used in windy and sandy areas. DETAILED DESCRIPTION

[0033] It should be noted that, unless there is a conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other. The described embodiments are only some embodiments of the present invention, not all embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is in no way intended to limit the present invention and its application or use. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative work are within the scope of protection of the present invention.

[0034] The present invention is described in more detail below through examples.

[0035] The composition of the steel according to the present invention is shown in Table 1, the main process parameters for smelting and continuous casting of the steel according to the present invention are shown in Table 2, the heating process parameters of the steel according to the present invention are shown in Table 3, the rolling and coiling process parameters of the steel according to the present invention are shown in Table 4, the various properties of the steel according to the present invention are shown in Table 5, the microstructure of the steel according to the present invention is shown in Table 6, and the results of the circumferential immersion corrosion test of the steel according to the present invention are shown in Table 7.

[0036] Table 1 Composition of steel according to the present invention (wt%)

[0037]

[0038]

[0039] Table 2 Main process parameters for steel smelting and continuous casting according to the embodiment of the present invention

[0040]

[0041] Table 3 Heating process of steel according to the present invention

[0042]

[0043] Table 4 Main process parameters of rolling and cooling of steel in the embodiment of the present invention

[0044]

[0045] Table 5 Test results of various performance indicators of the embodiment

[0046]

[0047] Table 6 Microstructure of steel according to the present invention

[0048]

[0049] As can be seen from Table 5, the yield strength of the example steels of the present invention is between 633 and 655 MPa, the tensile strength is between 812 and 842 MPa, the elongation is greater than 34%, and the yield strength ratio is between 0.77 and 0.79, indicating that the example steels have excellent plasticity and formability. The hardness value of the example steels is between 220 and 224 HBW.

[0050] The wear resistance tests reported in Table 5 were conducted on a wet rubber wheel abrasive wear tester. Samples measuring 57.0 mm × 25.5 mm × 6.0 mm were processed in accordance with JB / T 7705-1995, Test Method for Abrasive Wear of Loose Abrasive Grains - Rubber Wheel Method. The test results show that the wear rate of the example steel relative to Q345B ranged from 28.1% to 29.2%, demonstrating the steel's high wear resistance.

[0051] The results in Table 6 show that the microstructure of the invention steel is composed of ferrite + bainite + a small amount of pearlite. The microstructure is uniform and fine, and fine Mo2Si3 hard phases are precipitated in the microstructure. Among them, the proportion of Mo2Si3 in the size range of 40-70 μm is 86.4%-88.4%. This level of precipitate phase is beneficial to improving the wear resistance of the invention steel.

[0052] To simulate corrosion conditions in a C4 atmospheric environment, the invention steel was subjected to a 72-hour immersion rapid corrosion evaluation test according to the test method specified in TB / T 2375-1993. Table 7 compares the corrosion resistance of the invention steel and the reference steel. As can be seen from Table 7, the corrosion resistance of the invention steel is significantly superior to that of the reference steel Q345B.

[0053] Table 7 Comparison results of rapid corrosion test of steel according to the present invention and comparative steel

[0054]

[0055] It should be noted that the above embodiments are only for illustrating the technical concept and features of the present invention and are not intended to limit the present invention. Any equivalent replacement or modification that does not depart from the essence of the present invention shall fall within the scope of protection of the present invention.

Claims

1. A high-strength, wear-resistant, and corrosion-resistant steel for photovoltaic brackets with excellent plasticity, characterized in that: The chemical composition of steel is as follows by weight: C: 0.074% ~ 0.094%, Si: 0.39% ~ 0.57%, Mn: 0.91% ~ 1.16%, P: ≤ 0.016%, S: ≤ 0.006%, Cr: 1.03% ~ 1.27%, Cu: 0.16% ~ 0.24%, Sb: 0.106% ~ 0.126%, Ti: 0.051% ~ 0.071%, Mo: 0.20% to 0.32%, Ce: 0.0168% to 0.0188%, Als: 0.050% to 0.073%, wherein Si / Mo is controlled at 1.2 to 2.9, and the balance is Fe and unavoidable impurities; the manufacturing method includes smelting, slab continuous casting, billet heating, rolling, laminar cooling and coiling, the billet is heated to 1270 to 1296 ° C, the air-fuel ratio is between 1.6 and 2.0, and the heating temperature is 1 When the temperature is below 105℃, the heating rate is controlled at 6.2~8.3℃ / min; when the temperature is above 1105℃, the heating rate is controlled at 16.5~18.5℃ / min; the furnace time is controlled at ≤200min; the rolling adopts two-stage control rolling of rough rolling and finishing rolling, the finishing temperature of rough rolling is 1104~1139℃, the cumulative reduction rate of rough rolling stage is 82.1%~85.3%; the starting rolling temperature of finishing rolling is 1085℃~1113℃, and the finishing rolling temperature is 1104~1139℃. The finishing temperature is 932-948°C, the reduction rate of the last finishing rolling is controlled at 15.8%-16.7%, and the rolling crown target is controlled at 34-41µm. After finishing rolling, two-stage laminar cooling is adopted. In the first stage, the steel is cooled to 746-766°C at a cooling rate of 18-25°C / s, air-cooled for 8-10s, and then cooled in the second stage at a cooling rate of 29-39°C / s to 594-614°C for coiling.

2. The high-strength, wear-resistant and corrosion-resistant steel for photovoltaic brackets with excellent plasticity according to claim 1 is characterized in that: The metallographic structure of the steel is ferrite + bainite + a small amount of pearlite, with the ferrite proportion being 29.3%~31.1%, the bainite proportion being 59.5%~60.5%, and the ferrite grain size being ≥10.5; fine Mo2Si3 hard phase is precipitated in the structure, of which the Mo2Si3 with a size range of 40~70μm accounts for 86.4%~88.4%.

3. The high-strength, wear-resistant, and corrosion-resistant steel for photovoltaic supports with excellent plasticity according to claim 1 is characterized in that: The yield strength of the steel is between 633 and 655 MPa, the tensile strength is between 812 and 842 MPa, the elongation is greater than 34%, and the yield strength ratio is 0.77 to 0.79; The surface hardness of the steel is 220~224HBW, and the wear rate relative to Q345B is 28.1~29.2%.

4. The high-strength, wear-resistant, and corrosion-resistant steel for photovoltaic brackets with excellent plasticity according to claim 1 is characterized in that: In the rapid corrosion evaluation test under a simulated C4 atmospheric environment, the corrosion rate of steel was 0.998~1.09g / m 2 .h, the corrosion rate relative to Q345B is 29.74%~32.48%.

5. The high-strength, wear-resistant, and corrosion-resistant steel for photovoltaic supports with excellent plasticity according to claim 1 is characterized in that: The thickness of the steel plate is 1.8~4.0mm.

6. A method for manufacturing high-strength, wear-resistant, and corrosion-resistant steel for photovoltaic supports with excellent plasticity according to any one of claims 1 to 5, comprising smelting, slab continuous casting, slab heating, rolling, laminar cooling, and coiling, characterized in that: The ingot is heated to 1270-1296℃, with an air-fuel ratio of 1.6-2.

0. When the heating temperature is below 1105℃, the heating rate is controlled at 6.2-8.3℃ / min; when the temperature is above 1105℃, the heating rate is controlled at 16.5-18.5℃ / min; the furnace time is controlled at ≤200min; the rolling adopts two-stage controlled rolling of rough rolling and finishing rolling, the finishing rolling temperature of rough rolling is 1104-1139℃, the cumulative reduction rate of rough rolling stage is 82.1%-85.3%; finishing rolling The starting rolling temperature is 1085℃~1113℃, the finishing rolling temperature is 932~948℃, the reduction rate of the last finishing rolling is controlled at 15.8%~16.7%, and the rolling crown target is controlled at 34~41µm; after finishing rolling, two-stage laminar cooling is adopted. In the first stage, the steel is cooled to 746~766℃ at a cooling rate of 18~25℃ / s, air-cooled for 8~10s, and then cooled in the second stage at a cooling rate of 29~39℃ / s, cooled to 594~614℃ for coiling.

7. The method for manufacturing high-strength, wear-resistant, and corrosion-resistant steel for photovoltaic supports with excellent plasticity according to claim 6, characterized in that: During smelting, the molten iron is first pre-treated with desulfurization. After desulfurization, the S in the molten iron is ≤0.002%. The top and bottom composite blowing process is adopted, and the converter tapping temperature is 1646~1661℃. After that, Si-Ca wire feeding treatment is carried out to control the free O content in the steel below 3.6ppm; 20% Ce-Fe rare earth alloy 1.87~2.09kg / ton steel is added to the LF furnace 7~9min before the end of the vacuum treatment in the LF furnace, and then argon weak blowing is carried out.

8. The method for manufacturing high-strength, wear-resistant, and corrosion-resistant steel for photovoltaic supports with excellent plasticity according to claim 7, characterized in that: The flow rate of argon weak blowing is 110~130NL / min, the pressure is 0.18~0.31MPa, and the weak blowing time is 4.1~6.1min.

9. The method for manufacturing high-strength, wear-resistant, and corrosion-resistant steel for photovoltaic supports with excellent plasticity according to claim 6, characterized in that: The heating time of the ingot in the furnace is 172 to 195 minutes, of which the holding time in the soaking section is 32 to 47 minutes.

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