Hot-rolled steel strip for photovoltaic power generation bracket and preparation method of hot-rolled steel strip

Abstract

The invention provides a hot-rolled steel strip for a photovoltaic power generation support and a preparation method of the hot-rolled steel strip, and relates to the technical field of metallurgy, the steel tensile strength of the hot-rolled steel strip for the photovoltaic power generation support is larger than or equal to 500 MPa, the elongation is larger than or equal to 22%, and the hot-rolled steel strip for the photovoltaic power generation support comprises, by mass, 0.14%-0.17% of C, 0.08%-0.18% of Si, 0.45%-0.65% of Mn, the balance Fe and inevitable impurities. P: less than or equal to 0.020%; the alloy comprises the following components in percentage by weight: less than or equal to 0.015% of S, 0.010%-0.060% of Als, 0.005%-0.015% of Nb, 0.030%-0.045% of Ti and less than or equal to 0.006% of N; and the balance of Fe and inevitable impurities. The hot rolled steel strip for the photovoltaic power generation support has good strength and toughness, good formability and excellent comprehensive performance.

Description

Technical Field

[0001] The present invention relates to the technical field of metallurgy, and in particular to a hot-rolled steel strip for a photovoltaic power generation bracket and a preparation method thereof. Background Art

[0002] The global energy crisis has promoted the rapid development of the new energy industry, and solar energy is the most important basic energy among various renewable energy sources; therefore, the solar power generation technology that converts solar radiation energy into electrical energy, namely the photovoltaic industry, has developed rapidly.

[0003] Solar photovoltaic brackets are one of the important components of photovoltaic power generation projects. Their structure must be strong and reliable, and able to withstand atmospheric erosion, wind loads and other external effects. Steel brackets are widely used in civil and industrial solar photovoltaics and solar power stations because of their stable performance, mature manufacturing process, high bearing capacity and easy installation. At present, photovoltaic power generation support systems generally use carbon steel grade Q235B steel, but the strength is relatively low. With the rapid development of photovoltaic power generation, more and more researchers are committed to developing and using steel with high strength, excellent welding and excellent processability to meet existing needs. However, the steel strips used for photovoltaic power generation brackets in the prior art have low strength, unstable formability or high cost, which limits their application in photovoltaic power generation brackets. Summary of the invention

[0004] The problem solved by the present invention is that the steel strip used for photovoltaic power generation bracket in the prior art has low strength, unstable formability and high cost.

[0005] In order to solve the above problems, the present invention provides a hot-rolled steel strip for a photovoltaic power generation bracket, wherein the steel tensile strength of the hot-rolled steel strip for the photovoltaic power generation bracket is greater than or equal to 500MPa, and the elongation is greater than or equal to 22%, and the hot-rolled steel strip for the photovoltaic power generation bracket includes the following components in mass percentage: C: 0.14%-0.17%, Si: 0.08%-0.18%, Mn: 0.45%-0.65%, P: less than or equal to 0.020%; S is less than or equal to 0.015%, Als: 0.010%-0.060%, Nb: 0.005%-0.015%, Ti: 0.030%-0.045%, N: less than or equal to 0.006%; the remainder is Fe and unavoidable impurities.

[0006] The hot-rolled steel strip for photovoltaic power generation brackets described in the present invention adopts low-cost high-carbon and low-Mn, a small amount of niobium and a relatively high amount of titanium for compounding in terms of component design. The product has low alloy content and low production cost. In addition, ferrite + pearlite is formed by relying on the synergistic fine grain strengthening of Nb and Ti alloys and the precipitation strengthening of TiC two-phase particles, so that the hot-rolled steel strip for photovoltaic power generation brackets has good strength and toughness. The tensile strength of the steel is greater than or equal to 500MPa, and the yield strength is greater than or equal to 420MPa; the elongation is greater than or equal to 22%, and the strength of the steel plate is controlled within a stable range to ensure formability, and the comprehensive performance is excellent.

[0007] In order to solve the above problems, the present invention also provides a method for preparing a hot-rolled steel strip for a photovoltaic power generation bracket, comprising:

[0008] Step S1: desulfurizing the initial molten iron to obtain low-sulfur molten iron;

[0009] Step S2: pouring the low-sulfur molten iron and scrap steel into a converter, performing converter smelting, steel-tapping deoxidation and alloying treatment, and obtaining initial molten steel;

[0010] Step S3: sending the initial molten steel to an argon station for refining treatment to obtain treated molten steel;

[0011] Step S4: continuously casting the treated molten steel to obtain an initial slab;

[0012] Step S5: sending the initial slab to a heating furnace for heating treatment by adopting a hot charging and hot transporting process to obtain a heated slab;

[0013] Step S6: The heated slab is subjected to rough rolling, finish rolling, laminar flow cooling and coiling in sequence to obtain a hot-rolled steel strip for a photovoltaic power generation bracket.

[0014] Preferably, the deoxidation and alloying treatment in step S2 includes: using aluminum iron for deoxidation, and adding silicon manganese and medium carbon ferromanganese for alloying.

[0015] Preferably, in step S3, the refining treatment includes temperature measurement sampling, deoxidation, alloying and argon blowing treatment, and the deoxidation uses aluminum wire, and the alloying uses ferroniobium and ferrotitanium wire.

[0016] Preferably, in step S3, after the alloy is added in the alloying process and / or before the treated molten steel is tapped, the soft argon blowing time is greater than or equal to 5 minutes.

[0017] Preferably, in step S5, during the heating treatment process, when the thickness of the steel coil of the hot-rolled steel strip for photovoltaic power generation support is less than or equal to 2.6 mm, the heating temperature is 1190-1250°C; when the thickness of the steel coil is greater than 2.6 mm, the heating temperature is 1180-1240°C.

[0018] Preferably, in step S6, the rough rolling adopts double-stand multi-pass rolling, and the single-pass reduction ratio is greater than or equal to 20%, and the total reduction ratio is greater than or equal to 75%.

[0019] Preferably, in step S6, the start rolling temperature of the finish rolling is 1020-1080°C, and the final rolling temperature is 850-890°C.

[0020] Preferably, in step S6, during the coiling process, when the coil thickness of the hot-rolled steel strip for photovoltaic power generation support is less than or equal to 2.6 mm, the coiling temperature of the effective part of the hot-rolled steel strip for photovoltaic power generation support is 600-640°C; when the coil thickness is greater than 2.6 mm, the coiling temperature of the effective part of the hot-rolled steel strip for photovoltaic power generation support is 590-630°C.

[0021] Preferably, in step S6, the laminar cooling method includes front-end cooling, and U-shaped cooling is adopted at the head and tail parts of the hot-rolled steel strip for photovoltaic power generation support, and the coiling temperature of the head and tail parts is higher than the coiling temperature of the effective part, and the temperature difference is 10°C.

[0022] The method for preparing the hot-rolled steel strip for the photovoltaic power generation bracket of the present invention is simple, and the hot-rolled steel strip for the photovoltaic power generation bracket prepared by the method has good strength and toughness, the tensile strength of the steel is greater than or equal to 500MPa, the yield strength is greater than or equal to 420MPa; the elongation is greater than or equal to 22%, and the strength of the steel plate is controlled within a stable range to ensure formability, and the comprehensive performance is excellent. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a flow chart of a method for preparing a hot-rolled steel strip for a photovoltaic power generation bracket according to an embodiment of the present invention;

[0024] Figure 2 The microstructure of the hot-rolled steel strip for photovoltaic power generation support in the embodiment of the present invention is Figure 1 ;

[0025] Figure 3 The microstructure of the hot-rolled steel strip for photovoltaic power generation support in the embodiment of the present invention is Figure 2 ;

[0026] Figure 4 The microstructure of the hot-rolled steel strip for photovoltaic power generation support in the embodiment of the present invention is Figure 3 . DETAILED DESCRIPTION

[0027] The technical solutions in the embodiments of the present application will be described clearly and in detail below with reference to the accompanying drawings.

[0028] The term "some embodiments" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same implementation or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0029] An embodiment of the present invention provides a hot-rolled steel strip for a photovoltaic power generation bracket, wherein the steel tensile strength of the hot-rolled steel strip for the photovoltaic power generation bracket is greater than or equal to 500 MPa, and the elongation is greater than or equal to 22%, and the hot-rolled steel strip for the photovoltaic power generation bracket includes the following components in mass percentage: C: 0.14%-0.17%, Si: 0.08%-0.18%, Mn: 0.45%-0.65%, P: less than or equal to 0.020%; S is less than or equal to 0.015%, Als: 0.010%-0.060%, Nb: 0.005%-0.015%, Ti: 0.030%-0.045%, N: less than or equal to 0.006%; the remainder is Fe and unavoidable impurities.

[0030] It should be noted that, in this embodiment,

[0031] C: C is a cheap solid solution strengthening element. When the C content increases, the strength of the steel will continue to increase, but at the same time it will reduce the toughness and welding performance of the steel. Therefore, in this embodiment, the C content is 0.014%-0.17%, thereby ensuring both the strength of the final steel strip and the toughness and welding performance.

[0032] Si: Si is beneficial to improving the strength of the steel strip, but too high Si content can easily cause red iron scale on the steel surface that is difficult to remove. Therefore, in this embodiment, the Si content is 0.08%-0.18%, which ensures the strength of the steel strip and does not generate red iron scale.

[0033] Mn: Mn can effectively improve the performance of steel through solid solution strengthening and phase transformation strengthening. Specifically, Mn can refine the grains and significantly improve the strength of pearlite, but the elongation is reduced. In this embodiment, the Mn content is 0.45%-0.65%.

[0034] P and S: P and S are inclusion elements in steel. Phosphorus easily leads to product segregation and is easily concentrated at the grain boundary, reducing the plasticity and toughness of steel; sulfur easily forms MnS inclusions with good plasticity with manganese, and the long strips of MnS reduce the transverse tensile properties of the steel plate. Therefore, in order to ensure good mechanical properties of the steel plate, the P and S contents in this embodiment are as low as possible. Therefore, in this embodiment, the P content is less than or equal to 0.020%; the S content is less than or equal to 0.015%.

[0035] Als: Aluminum is a good deoxidizing element. When the aluminum content is less than 0.01%, it cannot exert its effect. However, adding too much aluminum easily forms aluminum oxide agglomerates and causes the weld to soften. Therefore, the aluminum content in this embodiment is 0.010%-0.060%.

[0036] Nb: The strengthening effect of Nb on steel is mainly fine grain strengthening and dispersion strengthening, which is specifically manifested in that Nb can generate stable carbides and carbonitrides with carbon and nitrogen in steel, and can also disperse carbides to form fine grained steel. Considering the mechanical properties and cost of the steel plate, in this embodiment, the content of Nb is 0.005%-0.015%.

[0037] Ti: Ti is the most important precipitation strengthening element in hot-rolled high-strength steel, which can make the internal structure of steel dense, refine the grains, reduce aging sensitivity and cold brittleness, and has a low cost. Therefore, in this embodiment, the content of Ti is 0.030%-0.045%.

[0038] N: The influence of N on the properties of steel is similar to that of carbon and phosphorus. With the increase of N content, the strength of steel can be significantly improved, while the plasticity, especially toughness, is significantly reduced, weldability is deteriorated, and cold brittleness is aggravated; at the same time, the aging tendency, cold brittleness and hot brittleness are increased, and the welding performance and cold bending performance of steel are damaged. Therefore, in this embodiment, the nitrogen content in steel is reduced and limited as much as possible, and the N content is less than or equal to 0.006%.

[0039] In summary, the hot-rolled steel strip for photovoltaic power generation brackets described in this embodiment adopts low-cost high carbon and low Mn, a small amount of niobium and a relatively high amount of titanium in the composition design. By adding relatively high titanium, the manganese and niobium content in the steel is greatly reduced, the alloy amount is relatively small, the production cost is low, and the ferrite + pearlite is formed by relying on the synergistic fine grain strengthening of Nb and Ti alloys and the precipitation strengthening of TiC two-phase particles, so that the hot-rolled steel strip for photovoltaic power generation brackets has excellent processing toughness and weldability while improving the strength. The tensile strength of the steel is greater than or equal to 500MPa, the yield strength is greater than or equal to 420MPa, the elongation is greater than or equal to 22%, and the strength of the steel plate is controlled within a stable range to ensure formability, and the comprehensive performance is excellent. In addition, the thickness specification of the steel strip for photovoltaic brackets in the embodiment of the present invention is 2.0-6.0mm, and the grain size is greater than or equal to grade 9.

[0040] like Figure 1 As shown, another embodiment of the present invention further provides a method for preparing a hot-rolled steel strip for a photovoltaic power generation bracket, comprising:

[0041] Step S1: desulfurizing the initial molten iron to obtain low-sulfur molten iron;

[0042] Step S2: pouring the low-sulfur molten iron and scrap steel into a converter, performing converter smelting, steel-tapping deoxidation and alloying treatment, and obtaining initial molten steel;

[0043] Step S3: sending the initial molten steel to an argon station for refining treatment to obtain treated molten steel;

[0044] Step S4: continuously casting the treated molten steel to obtain an initial slab;

[0045] Step S5: sending the initial slab to a heating furnace for heating treatment by adopting a hot charging and hot transporting process to obtain a heated slab;

[0046] Step S6: The heated slab is subjected to rough rolling, finish rolling, laminar flow cooling and coiling in sequence to obtain a hot-rolled steel strip for a photovoltaic power generation bracket.

[0047] In some preferred embodiments, the deoxidation and alloying treatment in step S2 includes: using aluminum iron for deoxidation, which is low-cost and beneficial to reducing the oxygen content and purifying the molten steel; and adding silicon manganese and medium carbon manganese iron for alloying, which is low-cost and helps to improve the strength and toughness of the steel.

[0048] In some preferred embodiments, in step S3, the refining treatment includes temperature measurement sampling, deoxidation, alloying and argon blowing treatment, and the deoxidation uses aluminum wire, and the alloying uses niobium iron and titanium iron wire, which increases the titanium yield and makes the composition more stable.

[0049] In some preferred embodiments, in step S3, after the alloy is added in the alloying process and / or before the treated molten steel is tapped, the soft argon blowing time is greater than or equal to 5 minutes, and the time from the end of the refining treatment to the start of ladle pouring when the treated molten steel is continuously cast in step S4 is greater than or equal to 10 minutes, so as to promote the floating removal of inclusions, reduce inclusions in the steel, and improve the cleanliness of the molten steel.

[0050] In some preferred embodiments, in step S5, during the heating process, when the thickness of the hot-rolled steel strip for photovoltaic power generation bracket is less than or equal to 2.6 mm, the heating temperature is 1190-1250° C.; when the thickness of the steel strip is greater than 2.6 mm, the heating temperature is 1180-1240° C. Therefore, strictly controlling the hot rolling temperature according to the steel strip thickness requirement helps to obtain a hot-rolled steel strip with excellent performance.

[0051] In addition, it should be noted that in the actual production process, the steel slabs are sometimes more than the batch of steel slabs in the order, and the excess steel slabs need to be transported to the warehouse for cooling. Therefore, when the cooled steel slabs are hot-rolled, they need to be heated in a heating furnace for 160-240 minutes to give full play to the fine grain strengthening effect of Nb and Ti.

[0052] In some preferred embodiments, in step S6, the rough rolling adopts double-stand multi-pass rolling. In some specific embodiments, double-stand 3+3-pass rolling is adopted, which has high output, wide rolling specification range, high rolling accuracy, and a single-pass reduction rate is greater than or equal to 20%, and a total reduction rate is greater than or equal to 75%, which helps to obtain hot-rolled steel strip with high strength, good toughness and excellent welding performance.

[0053] In some preferred embodiments, in step S6, the finishing rolling is performed by a 7-stand finishing rolling mill, and the starting rolling temperature is 1020-1080°C, and the final rolling temperature is 850-890°C, which helps to obtain a hot-rolled steel strip with high strength, good toughness and excellent welding performance.

[0054] In some preferred embodiments, in step S6, during the coiling process, when the coil thickness of the hot-rolled steel strip for photovoltaic power generation support is less than or equal to 2.6 mm, the coiling temperature of the effective part of the hot-rolled steel strip for photovoltaic power generation support is 600-640°C; when the coil thickness is greater than 2.6 mm, the coiling temperature of the effective part of the hot-rolled steel strip for photovoltaic power generation support is 590-630°C.

[0055] In some preferred embodiments, in step S6, the laminar cooling method includes front-end cooling, and U-shaped cooling is used at the head and tail parts of the hot-rolled steel strip for photovoltaic power generation support, and the coiling temperature of the head and tail parts is higher than the coiling temperature of the effective part, and the temperature difference is 10° C. The phenomenon of large performance fluctuations caused by uneven cooling at the head and tail parts is avoided, so that the steel coil has excellent uniformity of winding.

[0056] It should be noted that the head and tail parts in this embodiment refer to the parts within 10 meters from the two ends after the entire steel coil is unfolded, and the effective part refers to the part of the entire steel coil except the head and tail parts.

[0057] In some preferred embodiments, in step S6, the heated slab is descaled before rough rolling or finish rolling, so that the surface quality of the slab is improved and the appearance quality of the finished product is improved.

[0058] The method for preparing the hot-rolled steel strip for the photovoltaic power generation bracket described in the present invention is simple, and the hot-rolled steel strip for the photovoltaic power generation bracket prepared by the method has a thickness specification of 2.0-6.0 mm, a grain size greater than or equal to level 9, good strength and toughness, a steel tensile strength greater than or equal to 500 MPa, a yield strength greater than or equal to 420 MPa; an elongation greater than or equal to 22%, and the strength of the steel plate is controlled within a stable range to ensure formability, and the comprehensive performance is excellent.

[0059] Example 1

[0060] The present embodiment provides a hot-rolled steel strip for a photovoltaic power generation bracket, comprising the following components in mass percentage: C: 0.163%, Si: 0.167%, Mn: 0.506%, P: 0.0136%; S: 0.009%, Als: 0.0326%, Nb: 0.0131%, Ti: 0.0423%, N: 0.0029%; the remainder is Fe and unavoidable impurities.

[0061] The method for preparing the hot-rolled steel strip for photovoltaic power generation bracket in this embodiment includes:

[0062] Step S1: desulfurizing the initial molten iron to obtain low-sulfur molten iron;

[0063] Step S2: pouring the low-sulfur molten iron and scrap steel into a converter, performing converter smelting, steel-tapping deoxidation and alloying treatment to obtain initial molten steel, wherein aluminum iron is used for deoxidation, and silicon manganese and medium carbon ferromanganese are added for alloying;

[0064] Step S3: sending the initial molten steel to an argon station for refining treatment, and performing temperature measurement sampling, deoxidation, alloying, and argon blowing treatment to uniformize the composition and temperature to obtain treated molten steel, wherein aluminum wire is used for deoxidation, and ferroniobium and ferrotitanium wire are used for alloying, and in the alloying process, after the alloy is added and / or before the treated molten steel is tapped, the soft argon blowing time is 5 minutes;

[0065] Step S4: continuously casting the treated molten steel to obtain an initial slab, wherein the time from the end of the refining treatment to the start of ladle pouring when the treated molten steel is continuously cast in step S4 is 10 minutes;

[0066] Step S5: sending the initial slab to a heating furnace for heating treatment by using a hot charging and hot delivery process so that the initial slab is heated to a target tapping temperature to obtain a heated slab;

[0067] Step S6: The heated slab is subjected to rough rolling, finish rolling, laminar cooling and coiling in sequence to obtain a hot-rolled steel strip for photovoltaic power generation support, wherein the rough rolling adopts a double-stand 3+3-pass rolling, the finish rolling adopts a 7-stand finish rolling unit, and descaling is performed before rough rolling and finish rolling. The cooling rate in laminar cooling is 20°C / s, and front-stage cooling is adopted. U-type cooling is adopted at the head and tail parts of the hot-rolled steel strip for photovoltaic power generation support, and the coiling temperature at the head and tail parts is higher than the coiling temperature of the effective part, and the temperature difference is 10°C.

[0068] The difference between Examples 2-5 and Example 1 lies in the contents of the main components in the hot-rolled steel strip for photovoltaic power generation brackets and the hot rolling process parameters, as shown in Tables 1 and 2, and the mechanical properties test results of the hot-rolled steel strips obtained in each example are shown in Table 3.

[0069] Table 1 Chemical composition and mass percentage (wt%) of hot-rolled steel strips in various embodiments

[0070] Example C Si Mn P S Als Ti Nb N 1 0.163 0.167 0.506 0.0136 0.009 0.0326 0.0423 0.0131 0.0029 2 0.1598 0.144 0.476 0.0101 0.0098 0.0302 0.0441 0.0102 0.0022 3 0.1526 0.123 0.492 0.0134 0.0083 0.0325 0.0388 0.0093 0.0015 4 0.163 0.122 0.48 0.0165 0.010 0.0205 0.0429 - - 5 0.161 0.115 0.509 0.0159 0.011 0.027 0.034 - -

[0071] Table 2 Hot rolling process parameters in each embodiment

[0072]

[0073] Table 3 Mechanical properties test results of hot-rolled steel strips in various embodiments

[0074] Example Measured thickness (mm) Yield Strength(Mpa) Tensile strength(Mpa) Elongation(%) 1 3.0 554 607 33.0 2 3.5 513 591 28.5 3 4.0 518 590 27.5 4 3.0 494 577 32.5 5 3.75 416 510 30.0

[0075] It can be seen from the mechanical property test results of the hot-rolled steel strips in Examples 1-3 in Table 3 that the hot-rolled steel strips obtained in each example have high strength and good toughness. The tensile strength of the steel strips reaches more than 590 MPa, and the actual elongation reaches more than 27.5. It has high strength, good toughness, excellent weldability and low cost, and can meet the requirements of producing lightweight and high-strength photovoltaic power generation brackets. Figure 2-4 It can be seen that the hot-rolled steel strips obtained in Examples 1-3 have fine and uniform structures. Figure 2 This is a microstructure diagram of the hot-rolled steel strip for photovoltaic power generation support in Example 1; Figure 3 This is a microstructure diagram of the hot-rolled steel strip for photovoltaic power generation support in Example 2; Figure 4 This is the microstructure diagram of the hot-rolled steel strip for photovoltaic power generation support in Example 3.

[0076] In addition, it can be seen from the mechanical property test results of the hot-rolled steel strips in Examples 1-5 in Table 3 that in Examples 1-3 where Nb and Ti are used for composite strengthening at the same time, the tensile strength of the steel strip is basically stable at 590MPa, with good stability, and the maximum tensile strength can reach 607MPa. In Examples 4-5 where only Ti is used for strengthening, the tensile strength of the steel strip fluctuates greatly, especially when the Ti content is at the lower limit, there is a risk of tensile strength less than 500MPa, and when used to prepare photovoltaic power generation brackets, warping and deformation are prone to occur, and the formability is unstable. Therefore, by using Nb and Ti for composite strengthening at the same time, the tensile strength stability of the steel strip is better, which is more conducive to meeting the forming process required for high-precision processing of downstream photovoltaic power generation brackets.

[0077] Although the present invention is disclosed as above, the protection scope of the present invention is not limited thereto. Those skilled in the art may make various changes and modifications without departing from the spirit and scope of the present invention, and these changes and modifications will fall within the protection scope of the present invention.

Claims

1. A hot-rolled steel strip for photovoltaic power generation support, characterized in that: The steel tensile strength of the hot-rolled steel strip for photovoltaic power generation bracket is greater than or equal to 500MPa, and the elongation is greater than or equal to 22%, and the hot-rolled steel strip for photovoltaic power generation bracket includes the following components in mass percentage: C: 0.14%-0.17%, Si: 0.08%-0.18%, Mn: 0.45%-0.65%, P: less than or equal to 0.020%; S is less than or equal to 0.015%, Als: 0.010%-0.060%, Nb: 0.005%-0.015%, Ti: 0.030%-0.045%, N: less than or equal to 0.006%; the remainder is Fe and unavoidable impurities.

2. A method for preparing a hot-rolled steel strip for a photovoltaic power generation bracket according to claim 1, characterized in that: include: Step S1: desulfurizing the initial molten iron to obtain low-sulfur molten iron; Step S2: pouring the low-sulfur molten iron and scrap steel into a converter, performing converter smelting, steel-tapping deoxidation and alloying treatment, and obtaining initial molten steel; Step S3: sending the initial molten steel to an argon station for refining treatment to obtain treated molten steel; Step S4: continuously casting the treated molten steel to obtain an initial slab; Step S5: sending the initial slab to a heating furnace for heating treatment by adopting a hot charging and hot transporting process to obtain a heated slab; Step S6: The heated slab is subjected to rough rolling, finish rolling, laminar flow cooling and coiling in sequence to obtain a hot-rolled steel strip for a photovoltaic power generation bracket.

3. The method for preparing a hot-rolled steel strip for a photovoltaic power generation bracket according to claim 2, characterized in that: The deoxidation and alloying treatment in step S2 includes: using aluminum iron for deoxidation, and adding silicon manganese and medium carbon ferromanganese for alloying.

4. The method for preparing a hot-rolled steel strip for a photovoltaic power generation bracket according to claim 2, characterized in that: In step S3, the refining treatment includes temperature measurement sampling, deoxidation, alloying and argon blowing treatment, and the deoxidation uses aluminum wire, and the alloying uses niobium iron and titanium iron wire.

5. The method for preparing a hot-rolled steel strip for a photovoltaic power generation bracket according to claim 3 or 4, characterized in that: In step S3, after the alloy is added in the alloying process and / or before the treated molten steel is tapped, the soft argon blowing time is greater than or equal to 5 minutes.

6. The method for preparing a hot-rolled steel strip for a photovoltaic power generation bracket according to claim 2, characterized in that: In step S5, during the heating process, when the thickness of the steel coil of the hot-rolled steel strip for photovoltaic power generation support is less than or equal to 2.6 mm, the heating temperature is 1190-1250°C; when the thickness of the steel coil is greater than 2.6 mm, the heating temperature is 1180-1240°C.

7. The method for preparing a hot-rolled steel strip for a photovoltaic power generation bracket according to claim 2, characterized in that: In step S6, the rough rolling adopts double-stand multi-pass rolling, and the single-pass reduction rate is greater than or equal to 20%, and the total reduction rate is greater than or equal to 75%.

8. The method for preparing a hot-rolled steel strip for a photovoltaic power generation bracket according to claim 2, characterized in that: In step S6, the start rolling temperature of the finish rolling is 1020-1080°C, and the final rolling temperature is 850-890°C.

9. The method for preparing a hot-rolled steel strip for a photovoltaic power generation bracket according to claim 2, characterized in that: In step S6, during the coiling process, when the thickness of the hot-rolled steel strip for photovoltaic power generation support is less than or equal to 2.6 mm, the coiling temperature of the effective part of the hot-rolled steel strip for photovoltaic power generation support is 600-640°C; when the thickness of the steel coil is greater than 2.6 mm, the coiling temperature of the effective part of the hot-rolled steel strip for photovoltaic power generation support is 590-630°C.

10. The method for preparing a hot-rolled steel strip for a photovoltaic power generation bracket according to claim 9, characterized in that: In step S6, the laminar cooling method includes front-end cooling, and U-shaped cooling is adopted at the head and tail parts of the hot-rolled steel strip for photovoltaic power generation support, and the coiling temperature of the head and tail parts is higher than the coiling temperature of the effective part, and the temperature difference is 10°C.

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