Low-cost 550MPa high-performance photovoltaic zinc-aluminum-magnesium coated steel plate and manufacturing method thereof

Abstract

The invention discloses a low-cost 550MPa high-performance photovoltaic zinc-aluminum-magnesium coated steel plate and a manufacturing method thereof, and belongs to the technical field of hot dipping of steel plates. The components of the steel plate are controlled as follows: C: 0.008-0.045%; the steel comprises the following components in percentage by weight: less than or equal to 0.25% of P, less than or equal to 0.015% of S, less than or equal to 0.07% of Si, 0.50-0.90% of Mn, 0.35-0.85% of Cr, 0.02-0.15% of V, 0.025-0.045% of Alt and the balance of Fe and inevitable impurities. The manufacturing method comprises the procedures of acid rolling, hot rolling, annealing and galvanizing. The finish rolling temperature of the hot rolling procedure is 880 + / -20 DEG C, and the hot rolling coiling temperature is 470 + / -20 DEG C. A traditional continuous zinc-aluminum-magnesium hot-dip plating process is adopted, the produced 550MPa photovoltaic zinc-aluminum-magnesium plated steel plate is good in performance stability and small in production difficulty, and meanwhile the photovoltaic support machining requirement and the corrosion resistance requirement can be met.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of hot-dip plating of steel plates, and particularly relates to a low-cost 550MPa high-performance zinc-aluminum-magnesium plated steel plate for photovoltaics and a manufacturing method. BACKGROUND

[0002] Photovoltaic power generation can solve the power supply problem of people without electricity and poor areas, can solve the carbon emission problem of active power generation, and can also alleviate the energy crisis problem of oil and the like, so the prospect of photovoltaic power generation in China is good in recent years. The idle areas such as beaches, gobi, slopes, and seashores are mainly used for photovoltaic power generation, so the service environment of photovoltaics is relatively harsh.

[0003] The cell panel for power generation in a photovoltaic power generation assembly is made of metal materials, such as columns, supports, beams, shafts, guide rails, and accessories, and since the service environment of photovoltaics is not covered, the metal materials are generally required to be non-failed for 25 years. This puts a severe test on the corrosion resistance of the support, so the early photovoltaic support generally adopts post-dip galvanizing super-thick plating to ensure the corrosion resistance. With the continuous progress of continuous hot-dip plating technology, zinc-aluminum-magnesium plated products are recognized by the photovoltaic support industry due to their super corrosion resistance and unique functions such as panel protection. With the gradual progress of photovoltaic power generation technology, the size of the cell panel is also getting larger and larger, and the northwest gobi and other areas are gradually developing, so the strength requirement of the support is gradually increased from the initial 350MPa of the industry to 550MPa. At present, the realization means of high strength is generally to add alloy elements such as manganese, niobium, and titanium, so not only the alloy cost is high, but also the production cost is also high, and the profit space is small. SUMMARY

[0004] The purpose of the present application is to provide a low-cost 550MPa high-performance zinc-aluminum-magnesium plated steel plate for photovoltaics and a manufacturing method thereof, which can solve the problem of high alloy cost of high-grade structural steel.

[0005] To solve the above technical problems, the present application adopts the following technical scheme: a low-cost 550MPa high-performance zinc-aluminum-magnesium plated steel plate, the composition of the steel plate is controlled as follows: C: 0.008-0.045%; P≤0.25%, S≤0.015%, Si≤0.07%, Mn: 0.50-0.90%, Cr: 0.35-0.85%, V: 0.02-0.15%, Alt: 0.025-0.045%, and the rest is Fe and inevitable impurities.

[0006] The thickness of the steel plate is 0.5-2.5mm.

[0007] The tensile strength of the steel plate is 550-700MPa, the yield strength is 420-520MPa, and the elongation A50 is 5-15%.80% ≥15%.

[0008] Another object of the present invention is that the production method includes pickling, hot rolling, annealing, and galvanizing processes; the final rolling temperature of the hot rolling process is 880±20°C, and the hot rolling coiling temperature is 470±20°C.

[0009] In the acid rolling process of the present invention, the compression ratio of the acid rolling is ≤50%.

[0010] The annealing process of the present invention is as follows: 0.5mm≤t<0.75mm, annealing temperature: 510±10℃, soaking time: 82~92s; t: 0.75mm≤t<1.0mm, annealing temperature: 520±10℃, soaking time: 90~110s; t: 1.0mm≤t<1.30mm, annealing temperature: 530±10℃, soaking time: 100~120s; t: 1.30mm≤t<1.60mm, annealing Temperature: 540±10℃, soaking time: 110~130s; t: 1.60mm≤t<1.90mm, annealing temperature: 550±10℃, soaking time: 120~140s; t: 1.90mm≤t<2.20mm, annealing temperature: 560±10℃, soaking time: 130~150s; t: 2.20mm≤t<2.50mm, annealing temperature: 570±10℃, soaking time: 140~160s, where t is the thickness of the strip.

[0011] In the galvanizing process of the present invention, when t≤1.5mm, the plating solution temperature T1 is 415±5°C; when t>1.5mm, the plating solution temperature T1 is 425±5°C.

[0012] The zinc plating process of the present invention has the following plating solution components: Al: 1.6±0.5%, Mg: 1.6±0.5%, Re: 0.01-0.06%, and the remainder is zinc.

[0013] The tensile strength difference range of the steel plate obtained by the method of the present invention is ≤150MPa.

[0014] The steel plate obtained by the method of the present invention is tested for corrosion resistance, and under neutral salt spray conditions, the red rust resistance time is more than 3500 hours.

[0015] The present invention improves the hardenability and austenite stability of the steel plate by adding a certain amount of manganese, chromium, and vanadium. By controlling the coiling temperature during hot rolling, an ideal iron-bainite dual-phase structure is achieved, achieving strength requirements through structural strengthening. The present invention reduces the driving force for recrystallization of the steel plate by using the cold rolling reduction ratio. Simultaneously, the annealing temperature and holding time are reduced to prevent bainite decomposition and the degree of recrystallization, achieving the required 550 MPa strength level.

[0016] The beneficial effects produced by the above technical solutions are as follows: 1. The reasonable alloy composition design, reasonable hot rolling finishing and low-temperature coiling adopted by the application obtain ferrite + bainite dual-phase structure. 2. The low compression ratio adopted by the application can reduce the dynamic force of the steel plate to occur recovery recrystallization, so that the steel plate obtains the same structure as the original hot rolling structure, to obtain higher and stable mechanical properties. 3. The narrow range of low-temperature annealing temperature adopted by the application avoids the complete recovery recrystallization of the steel plate and reduces the strength of the steel plate. 4. The 550MPa zinc-aluminum-magnesium coated steel plate for photovoltaic produced by the application has good performance stability (the tensile strength difference range is within 150MPa), has small production difficulty, and can meet the processing requirements and corrosion resistance (under the neutral salt spray condition, the red rust resistance time is more than 3500 hours) requirements of the photovoltaic support. DETAILED DESCRIPTION

[0017] In order to make the purpose, technical scheme and advantages of the application more clear, the application will be further described in detail below in combination with examples. It should be understood that the specific examples described herein are only used to explain the application, and are not used to limit the application.

[0018] Examples 1-11 A low-cost 550MPa high-performance zinc-aluminum-magnesium coated steel plate for photovoltaic, the chemical composition and mass percentage are shown in Table 1, and the steel plate specification and performance test results are shown in Table 2. The manufacturing method includes the processes of acid rolling, hot rolling, annealing and galvanizing; the specific control method is as follows: 1) The finishing temperature of the hot rolling process is 880±20℃, and the hot rolling coiling temperature is 470±20℃, and the control parameters of each example are shown in Table 3.

[0019] 2) The acid rolling process, the compression ratio of acid rolling is ≤50%, and the control parameters of each example are shown in Table 3.

[0020] 3) annealing process, annealing temperature system of the strip steel is: 0.5mm≤t<0.75mm, annealing temperature: 510±10℃, soaking time is: 82-92s; t: 0.75mm≤t<1.0mm, annealing temperature: 520±10℃, soaking time is: 90-110s; t: 1.0mm≤t<1.30mm, annealing temperature: 530±10℃, soaking time is: 100-120s; t: 1.30mm≤t<1.60mm, annealing temperature: 540±10℃, soaking time is: 110-130s; t: 1.60mm≤t<1.90mm, annealing temperature: 550±10℃, soaking time is: 120-140s; t: 1.90mm≤t<2.20mm, annealing temperature: 560±10℃, soaking time is 130-150s; t: 2.20mm≤t<2.50mm, annealing temperature: 570±10℃, soaking time is: 140-160s, the t is the thickness of the strip steel, the control parameters of each example are shown in Table 3.

[0021] 3) zinc-aluminum-magnesium coating process, t≤1.5mm, plating solution temperature T1: 415±5℃; t>1.5mm, plating solution temperature T1: 425±5℃, the control parameters of each example are shown in Table 3.

[0022] 4) zinc-aluminum-magnesium coating process, plating solution composition: Al: 1.6±0.5%, Mg: 1.6±0.5%, Re: 0.01-0.06%, the rest is zinc, the control parameters of each example are shown in Table 3, finally obtaining a low-cost 550MPa high-performance photovoltaic zinc-aluminum-magnesium coated steel plate.

[0023] Table 1 Chemical composition of each example steel plate (% by weight)

[0024] Table 2 Performance test results of each example steel plate

[0025] Table 3 Control parameters of each example manufacturing process

[0026] The above examples are only used to illustrate and not to limit the technical solutions of the present application, although the present application has been described in detail with reference to the above examples, those skilled in the art should understand that the present application can still be modified or equivalently replaced without departing from the spirit and scope of the present application, any modification or partial replacement should be covered in the scope of the claims of the present application.

Claims

1. Low-cost 550MPa high-performance photovoltaic zinc-aluminum-magnesium coated steel sheet, characterized by: The composition of the steel plate is controlled as follows: C: 0.008-0.045%; P≤0.25%, S≤0.015%, Si≤0.07%, Mn: 0.50-0.90%, Cr: 0.35-0.85%, V: 0.02-0.15%, Alt: 0.025-0.045%, and the rest is Fe and unavoidable impurities.

2. The low-cost 550MPa high-performance photovoltaic zinc-aluminum-magnesium coated steel sheet according to claim 1, characterized in that: The thickness of the steel plate ranges from 0.5 to 2.5 mm.

3. The low-cost 550MPa high-performance photovoltaic zinc-aluminum-magnesium coated steel sheet according to claim 1 or 2, characterized in that: The steel plate has a tensile strength of 550-700 MPa, a yield strength of 420-520 MPa, and an elongation of A 80% ≥15%.

4. The method for producing a low-cost 550 MPa high-performance photovoltaic zinc-aluminum-magnesium coated steel sheet according to any one of claims 1 to 3, characterized in that: The manufacturing method includes pickling, hot rolling, annealing and galvanizing processes; the final rolling temperature of the hot rolling process is 880±20°C, and the hot rolling coiling temperature is 470±20°C.

5. The method for producing a low-cost 550MPa high-performance photovoltaic zinc-aluminum-magnesium coated steel sheet according to claim 4, characterized in that: In the pickling process, the compression ratio of the pickling is ≤50%.

6. The method for manufacturing a low-cost 550 MPa high-performance photovoltaic zinc-aluminum-magnesium coated steel sheet according to claim 4, characterized in that: The annealing process of the strip steel is as follows: 0.5mm≤t<0.75mm, annealing temperature: 510±10℃, soaking time: 82~92s; t: 0.75 mm≤t<1.0mm, annealing temperature: 520±10℃, soaking time: 90~110s; t: 1.0mm≤t<1.30mm, annealing temperature: 530±10℃, soaking time: 100~120s; t: 1.30mm≤t<1.60mm, annealing temperature: 540±10℃, soaking time: 110~130s; t: 1.60mm≤t<1.90mm, annealing temperature: 550±10℃, soaking time: 120~140s; t: 1.90mm≤t<2.20mm, annealing temperature: 560±10℃, soaking time: 130~150s; t: 2.20mm≤t<2.50mm, annealing temperature: 570±10℃, soaking time: 140~160s, where t is the thickness of the strip.

7. The method for producing a low-cost 550MPa high-performance photovoltaic zinc-aluminum-magnesium coated steel sheet according to any one of claims 4 to 6, characterized in that: In the galvanizing process, when t≤1.5mm, the plating bath temperature T1 is 415±5°C; when t>1.5mm, the plating bath temperature T1 is 425±5°C.

8. The method for producing a low-cost 550MPa high-performance photovoltaic zinc-aluminum-magnesium coated steel sheet according to any one of claims 4 to 6, characterized in that: In the zinc plating process, the plating solution composition is as follows: Al: 1.6±0.5%, Mg: 1.6±0.5%, Re: 0.01-0.06%, and the rest is zinc.

9. The method for producing a low-cost 550MPa high-performance photovoltaic zinc-aluminum-magnesium coated steel sheet according to any one of claims 4 to 6, characterized in that: The tensile strength difference of the steel plate obtained by the method is within a range of ≤150 MPa.

10. The method for producing a low-cost 550MPa high-performance photovoltaic zinc-aluminum-magnesium coated steel sheet according to any one of claims 4 to 6, characterized in that: The steel plate obtained by the method is tested for corrosion resistance, and the red rust resistance time under neutral salt spray conditions is more than 3500 hours.

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