Low-cost and high-corrosion-resistance steel plate for photovoltaic steel frame and manufacturing method of low-cost and high-corrosion-resistance steel plate

Abstract

The invention relates to a low-cost and high-corrosion-resistance steel plate for a photovoltaic steel frame and a manufacturing method of the low-cost and high-corrosion-resistance steel plate. A base plate of the steel plate comprises the following chemical components in percentage by mass: 0.200-0.230% of C, 0.90-1.10% of Mn, less than or equal to 0.005% of S, less than or equal to 0.022% of P, 0.10-0.20% of Si, 0.025-0.050% of Als, 0.025-0.035% of Ti, less than or equal to 0.0060% of N and the balance of Fe and inevitable impurities. The manufacturing method comprises the working procedures of acid continuous rolling, continuous hot-dip galvanizing, aluminum and magnesium plating, finishing, color coating and rolling. The steel plate for the photovoltaic steel frame, provided by the invention, has the characteristics of low cost, high surface, high corrosion resistance, high strength, high ductility and high deformation resistance.

Description

Technical Field

[0001] The invention belongs to the field of coating technology, and specifically relates to a low-cost, high-corrosion-resistant steel plate for photovoltaic steel frame and a manufacturing method thereof Background Art

[0002] With the implementation of the national green and low-carbon environmental protection policies, all industries are undergoing transformation and upgrading to reduce carbon emissions. As an emerging industry of green electricity, the photovoltaic industry has been in a growth trend in recent years, driving the rapid development of photovoltaic components. At present, photovoltaic brackets are generally produced using zinc-aluminum-magnesium steel plates. The frame material for fixing the solar panels in photovoltaic modules is mainly aluminum alloy. The photovoltaic frame has high requirements for surface, size, corrosion resistance, strength, fatigue performance, etc.

[0003] With the development of the optoelectronics industry, the demand for cost reduction by photovoltaic module manufacturers is becoming increasingly strong due to the price constraints of silicon wafers and aluminum alloys. In order to reduce production costs and improve market competitiveness, it is urgent to develop a low-cost, high-corrosion-resistant photovoltaic steel frame to replace the aluminum frame. Since steel materials still have a gap in surface appearance and corrosion resistance compared to aluminum materials, how to improve appearance and corrosion resistance while ensuring roll forming properties is also a problem that needs to be solved. Summary of the invention

[0004] The purpose of the present invention is to provide a low-cost, high-corrosion-resistant steel plate for photovoltaic steel frames and a manufacturing method thereof, which can reduce the cost by more than 30% compared with aluminum frames, and has the characteristics of good surface and high corrosion resistance, meeting the use requirements of photovoltaic frames.

[0005] To achieve the above object, the technical solution adopted by the present invention is:

[0006] A low-cost, high-corrosion-resistant steel plate for photovoltaic steel frames, wherein the chemical composition and mass percentage of the substrate are C: 0.200-0.230%, Mn: 0.90-1.10%, S≤0.005%, P≤0.022%, Si: 0.10-0.20%, Als: 0.025-0.050%, Ti: 0.025-0.035%, N≤0.0060%, and the rest are Fe and unavoidable impurities.

[0007] The method for manufacturing the low-cost, high-corrosion-resistant steel plate for photovoltaic steel frame of the present invention comprises the steps of acid continuous rolling, continuous hot-dip galvanizing, aluminum-magnesium coating, skin finishing, color coating and roller pressing.

[0008] In the acid continuous rolling process, the cold rolling reduction rate is 66-72%.

[0009] In the continuous hot-dip galvanizing aluminum-magnesium process, the strip speed is 90-110 m / min and the soaking zone temperature is 660-680°C.

[0010] The skin-passing process uses a constant rolling force mode, and the skin-passing rolling force is 1900-2000 KN.

[0011] The color coating process is to color coat the galvanized aluminum-magnesium steel coil, and the type of topcoat is selected from one of polyester topcoat, high weather-resistant topcoat, and fluorocarbon topcoat. The thickness of the front primer is 5 to 10 μm, the thickness of the topcoat is 10 to 15 um, and the color of the topcoat is black, white, and gray. The reverse side uses epoxy back paint, and the paint film thickness is 5 to 10 um.

[0012] The reason for designing the color coating process: zinc-aluminum-magnesium steel frames are prone to black spots, blackening and other surface problems during transportation, which affect the appearance of the product. Due to the limitations of steel and aluminum frame materials and processing characteristics, the corrosion resistance of steel frames is poor. In order to make the product more beautiful and improve the corrosion resistance of the product, the galvanized aluminum-magnesium steel coils are color coated before producing steel frames. Based on the consideration of material cost and corrosion resistance, the above-mentioned paint types and paint film thicknesses are selected.

[0013] The rolling process uses 0.6 mm plate to produce a closed steel frame through multiple rolling deformations, and uses 1.1 mm or 1.2 mm plate to produce an open steel frame through multiple rolling deformations.

[0014] The double-sided coating weight of the zinc-aluminum-magnesium coated steel plate is 275-310 g / m 2

[0015] The coating composition includes: Al: 1.5-1.7%, Mg: 1.1-1.4%.

[0016] The present invention designs the low-aluminum and low-magnesium zinc-aluminum-magnesium coating composition, and the obtained coating has good surface quality. At the same time, the coating has low hardness and good ductility. The number and depth of coating cracks are smaller during processing, which helps to improve the corrosion resistance of the bending and deformation positions of the steel frame.

[0017] The steel plate has a yield strength of ≥600 MPa, a tensile strength of ≥650 MPa, and an elongation A80 of ≥11%.

[0018] The beneficial effects produced by the above technical scheme are: 1. The titanium micro-alloying composition design is adopted. Compared with traditional high-strength steel, no Nb is added, and the product cost is low. Compared with aluminum frames, the cost of steel frames produced by the present invention can be reduced by more than 30%. 2. The steel plate of the present invention has a yield strength of ≥600MPa, a tensile strength of ≥650MPa, and an elongation A80 of ≥11%. It has the characteristics of high strength and high elongation, strong deformation resistance, and meets the lightweight requirements of steel frames. 3. The product has high corrosion resistance, and the neutral salt spray time of the steel frame can reach more than 1500h, which meets the corrosion resistance requirements of areas other than coastal areas. 4. The present invention has a low aluminum and low magnesium coating composition. Compared with medium aluminum and high aluminum products, it has excellent surface quality, few coating cracks after bending, shallow coating cracks, and excellent processing formability. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is the cross-sectional metallographic structure of the zinc-aluminum-magnesium steel plate produced in Example 6. DETAILED DESCRIPTION

[0020] The present invention will be further described in detail below in conjunction with specific embodiments.

[0021] Examples 1-8

[0022] A low-cost, high-corrosion-resistant steel plate for photovoltaic steel frame, the chemical composition and mass percentage of the substrate are C: 0.200-0.230%, Mn: 0.90-1.10%, S≤0.005%, P≤0.022%, Si: 0.10-0.20%, Als: 0.025-0.050%, Ti: 0.025-0.035%, N≤0.0060%, and the rest is Fe and unavoidable impurities. The chemical composition and content of the steel plate substrate of each embodiment are shown in Table 1.

[0023] Table 1 Chemical composition of steel plate substrates in various embodiments by weight percentage (%)

[0024] Example C Mn S P Si Als N Ti 1 0.200 0.90 0.005 0.022 0.10 0.025 0.0060 0.025 2 0.230 1.10 0.004 0.012 0.20 0.050 0.0035 0.035 3 0.213 1.09 0.001 0.021 0.15 0.032 0.0031 0.031 4 0.208 1.05 0.001 0.018 0.14 0.035 0.0040 0.033 5 0.207 1.04 0.002 0.013 0.15 0.041 0.0046 0.028 6 0.206 1.04 0.002 0.011 0.16 0.029 0.0041 0.025 7 0.218 1.07 0.003 0.016 0.16 0.046 0.0054 0.029 8 0.216 1.06 0.003 0.015 0.15 0.042 0.0047 0.034

[0025] The manufacturing method of the above-mentioned low-cost, high-corrosion-resistant steel plate for photovoltaic steel frame includes acid continuous rolling, continuous hot-dip galvanizing aluminum-magnesium, skin pass, color coating, and roller pressing processes; the details are as follows:

[0026] (1) Acid continuous rolling: The cold rolling reduction rate is 66-72%.

[0027] (2) Continuous hot-dip galvanizing aluminum-magnesium: the strip speed is 90-110 m / min, and the temperature in the soaking section is 660-680°C.

[0028] (3) Leveling: Use the constant rolling force mode, and the skin-pass rolling force is 1900~2000KN.

[0029] (4) Color coating: The galvanized aluminum-magnesium steel coil is color coated. The topcoat type is selected from polyester topcoat, high weather-resistant topcoat, and fluorocarbon topcoat. The thickness of the front primer is 5-10μm, and the thickness of the topcoat is 10-15um. The color of the topcoat is black, white, or gray. The back is coated with epoxy backcoat, and the paint film thickness is 5-10um.

[0030] (5) Rolling: Use 0.6mm plate to produce closed steel frames through multiple rolling deformations, and use 1.1mm or 1.2mm plate to produce open steel frames through multiple rolling deformations.

[0031] The cold rolling reduction ratio, strip speed, soaking zone temperature, skin-pass rolling force, and steel plate properties during the production of the steel plates in each embodiment are shown in Table 2.

[0032] Table 2 Production process parameters and steel plate properties of each example

[0033]

[0034] The coating composition of the steel plates of each embodiment, the coating weight on both sides of the zinc-aluminum-magnesium coated steel plates, the type of paint and the thickness are shown in Table 3.

[0035] Table 3 Coating composition, double-sided coating weight, coating type and thickness of steel plates in various examples

[0036]

[0037]

[0038] The cross-sectional metallographic structure of the galvanized aluminum-magnesium steel sheet produced in Example 6 is shown in FIG. Figure 1 ,Depend on Figure 1 It can be seen that its metallographic structure is ferrite + pearlite.

[0039] The above embodiments are only used to illustrate rather than limit the technical solutions of the present invention. Although the present invention is described in detail with reference to the above embodiments, those skilled in the art should understand that the present invention can still be modified or replaced by equivalents. Any modification or partial replacement that does not depart from the spirit and scope of the present invention should be included in the scope of the claims of the present invention.

Claims

1. A low-cost, high-corrosion-resistant steel plate for photovoltaic steel frames, characterized in that: The chemical composition and mass percentage of the substrate are C: 0.200-0.230%, Mn: 0.90-1.10%, S≤0.005%, P≤0.022%, Si: 0.10-0.20%, Als: 0.025-0.050%, Ti: 0.025-0.035%, N≤0.0060%, and the rest are Fe and unavoidable impurities.

2. The method for manufacturing the low-cost, high-corrosion-resistant steel plate for photovoltaic steel frame according to claim 1, characterized in that: It includes acid continuous rolling, continuous hot-dip galvanizing aluminum-magnesium, skin finishing, color coating and roller pressing processes.

3. The method for manufacturing a low-cost, high-corrosion-resistant steel plate for photovoltaic steel frame according to claim 2, characterized in that: In the acid continuous rolling process, the cold rolling reduction rate is 66-72%.

4. The method for manufacturing a low-cost, high-corrosion-resistant steel plate for photovoltaic steel frame according to claim 2, characterized in that: In the continuous hot-dip galvanizing aluminum-magnesium process, the strip speed is 90-110 m / min and the soaking zone temperature is 660-680°C.

5. The method for manufacturing a low-cost, high-corrosion-resistant steel plate for photovoltaic steel frame according to claim 2, characterized in that: The smoothing process uses a constant rolling force mode, and the skin-pass rolling force is 1900-2000 KN.

6. The method for manufacturing a low-cost, high-corrosion-resistant steel plate for photovoltaic steel frame according to claim 2, characterized in that: The color coating process is to color coat the galvanized aluminum-magnesium steel coil, and the type of topcoat is selected from one of polyester topcoat, high weather-resistant topcoat, and fluorocarbon topcoat. The thickness of the front primer is 5 to 10 μm, the thickness of the topcoat is 10 to 15 um, and the color of the topcoat is black, white, and gray. The reverse side uses epoxy back paint, and the paint film thickness is 5 to 10 um.

7. The method for manufacturing a low-cost, high-corrosion-resistant steel plate for photovoltaic steel frame according to claim 2, characterized in that: The rolling process uses 0.6 mm plates to produce closed steel frames through multiple rolling deformations, and uses 1.1 and 1.2 mm plates to produce open steel frames through multiple rolling deformations.

8. The method for manufacturing a low-cost, high-corrosion-resistant photovoltaic steel frame steel plate according to claim 2, characterized in that: The thickness of the steel plate is 0.6, 1.1 or 1.2 mm.

9. The method for manufacturing a low-cost, high-corrosion-resistant steel plate for photovoltaic steel frame according to claim 2, characterized in that: The double-sided coating weight of the steel plate is 275-310 g / m 2 .

10. The method for manufacturing a low-cost, high-corrosion-resistant steel plate for photovoltaic steel frame according to claim 2, characterized in that: The steel plate has a yield strength of ≥600MPa, a tensile strength of ≥650MPa, and an elongation of A 80 ≥11%.

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