Production method of weathering steel with good low-temperature impact toughness for photovoltaic support

Abstract

The invention discloses a production method of weathering resistant steel with good low-temperature impact toughness for a photovoltaic support. Main process parameters are as follows: a smelting-continuous casting production process flow: chemical components of molten steel in percentage by mass are limited; the hot rolling production process comprises the steps of blank casting, an induction heating furnace, a laboratory rolling mill, laminar cooling and simulated coiling. Wherein the tapping temperature of the casting blank is 1240 + / -20 DEG C, the finish rolling temperature of finish rolling is 890 DEG C, the cooling speed is 10-20 DEG C / S, and the thickness of a hot rolled steel strip is 8 mm; laminar cooling equipment is adopted for cooling, a pre-dispersion cooling mode is adopted, and the coiling temperature is 630 + / -10 DEG C. According to the production method of the weathering resistant steel for the photovoltaic support with the good low-temperature impact toughness, a conventional C, S i and Mn component system design is adopted, the corrosion resistance of a steel strip is improved by adding corrosion-resistant elements Cu, Cr, P, T i and Ni, and meanwhile the weathering resistant steel has the excellent mechanical property, especially the low-temperature toughness.

Description

Technical Field

[0001] The invention belongs to the technical field of metallurgical plate production, and in particular relates to a production method of weathering steel for photovoltaic brackets with good low-temperature impact toughness. Background Art

[0002] The steel used in photovoltaic brackets is concentrated in the bracket structure. The bracket structure is mainly composed of components such as columns, main beams, purlins, etc. The raw materials are mainly: aluminum alloy, 304 stainless steel, Q235 steel plate + hot-dip galvanized steel parts, galvanized plates, zinc-aluminum-magnesium plates, weather-resistant steel plates, etc. At present, Q235 steel plate + hot-dip galvanized steel parts are the main photovoltaic bracket parts. The production of components is to cold-bending, stamping, sawing, laser cutting, plasma cutting, welding, hot-dip galvanizing and other processing processes on the steel plates, which have high requirements on product processing accuracy, production efficiency and quality consistency.

[0003] Corrosion resistance, high strength and good fatigue performance are the most important requirements for photovoltaic bracket materials. It is necessary to ensure that the steel structure is firm and reliable within 25 years, and can withstand harsh environmental erosion, wind, snow loads and other external effects, and achieve the maximum use effect with the minimum installation cost. In the early stage, galvanized brackets were widely used due to their stable performance, mature manufacturing process, high bearing capacity and easy installation. However, as people's requirements for the cost-effectiveness of photovoltaic projects become higher and higher, photovoltaic brackets are accelerating towards high strength, lightweight and green development. Weathering steel brackets are increasingly favored by large domestic photovoltaic power station projects due to their good corrosion resistance, environmental protection and high cost-effectiveness. Summary of the invention

[0004] The purpose of the present invention is to provide a method for producing weathering steel for photovoltaic brackets with good low-temperature impact toughness. The present invention adopts a conventional C, Si, and Mn component system design, and improves the corrosion resistance of the steel strip by adding corrosion-resistant elements Cu, Cr, P, Ti, and Ni. At the same time, the steel strip has excellent mechanical properties, especially low-temperature toughness.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0006] The present invention provides a method for producing weathering steel for photovoltaic brackets with good low-temperature impact toughness, and the main process parameters are as follows:

[0007] Smelting-continuous casting production process: The chemical composition of the molten steel by mass percentage is C: 0.06-0.08%, Si: 0.20-0.30%, Mn: 0.7-0.9%, P: 0.03-0.06%, S: ≤0.008%, Cu: 0.20-0.25%, Cr: 1.8-2.0%, Ni: 0.04-0.06%, Ti: 0.08-0.10%, Alt: 0.020-0.050%, and the rest is Fe and impurities;

[0008] Hot rolling production process: ingot - induction heating furnace - laboratory rolling mill - laminar cooling - simulated coiling; wherein: the ingot out of the furnace temperature is 1240±20℃, the final rolling temperature of the finishing rolling is 890℃, the cooling rate is 10-20℃ / S, the hot rolled steel strip thickness is 8mm; cooling adopts laminar cooling equipment, front dispersed cooling mode, and the coiling temperature is 630±10℃.

[0009] Furthermore, the rolling is carried out using a traditional 2250 hot rolling production line, the slab heating temperature is 1250°C, the holding time is 48 minutes, and the hot rolling mill is used for rolling; the finishing rolling temperature is 893°C, and the finished product thickness is 7mm; the laminar cooling adopts front dispersed cooling, the cooling rate is 20°C / S, and the steel strip temperature is reduced to 640°C for coiling.

[0010] Furthermore, the rolling is carried out using a traditional 2250 hot rolling production line, the slab heating temperature is 1250°C, the holding time is 50 minutes, and the hot rolling mill is used for rolling; the finishing rolling temperature is 888°C, and the finished product thickness is 7mm; the laminar cooling adopts front dispersed cooling, the cooling rate is 18°C / S, and the steel strip temperature is reduced to 640°C for coiling.

[0011] Furthermore, the rolling is carried out using a traditional 2250 hot rolling production line, the slab heating temperature is 1243°C, the heating time is 50 minutes, and the hot rolling mill is used for rolling; the finishing rolling temperature is 892°C, and the finished product thickness is 7mm; the laminar cooling adopts front dispersed cooling, the cooling rate is 19°C / S, and the steel strip temperature is reduced to 640°C for coiling.

[0012] Furthermore, the chemical composition of the weathering steel in mass percentage is: C: 0.07%, Si: 0.25%, Mn: 0.83%, P: 0.051%, S: 0.004%, Cu: 0.23%, Cr: 1.89%, Ni: 0.046%, Ti: 0.090%, Alt: 0.030%, and the rest is Fe and impurities.

[0013] Furthermore, the chemical composition of the weathering steel in mass percentage is: C: 0.07%, Si: 0.25%, Mn: 0.83%, P: 0.047%, S: 0.003%, Cu: 0.23%, Cr: 1.87%, Ni: 0.052%, Ti: 0.085%, Alt: 0.031%, and the rest is Fe and impurities.

[0014] Furthermore, the chemical composition of the weathering steel by mass percentage is: C: 0.07%, Si: 0.25%, Mn: 0.81%, P: 0.052%, S: 0.003%, Cu: 0.25%, Cr: 1.89%, Ni: 0.055%, Ti: 0.088%, Alt: 0.030%, and the rest is Fe and impurities.

[0015] Compared with the prior art, the beneficial technical effects of the present invention are:

[0016] The metallographic microstructure of the steel of the present invention is bainite + a small amount of ferrite. The high and low temperature impact toughness weathering steel for photovoltaic brackets produced by the method provided by the present invention has been tested and its mechanical properties and process properties meet relevant standards and user requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The present invention will be further described below in conjunction with the accompanying drawings.

[0018] Figure 1 This is the microstructure diagram of Example 1 of the present invention. DETAILED DESCRIPTION

[0019] The present invention is described in more detail below through specific examples. The examples are only descriptions of the best mode of implementation of the present invention and do not limit the scope of the present invention in any way.

[0020] Example 1

[0021] The rolling is carried out using the traditional 2250 hot rolling production line. The slab heating temperature is 1250℃, the holding time is 48min, and the hot rolling mill is used for rolling. The finishing rolling temperature is 893℃, and the finished product thickness is 7mm. The laminar cooling adopts front dispersion cooling, the cooling rate is 20℃ / S, and the steel strip temperature is reduced to 640℃ for coiling. Finally, the product performance test is carried out.

[0022] Example 2

[0023] The rolling is carried out using the traditional 2250 hot rolling production line. The slab heating temperature is 1250℃, the holding time is 50min, and the hot rolling mill is used for rolling. The finishing rolling temperature is 888℃, and the finished product thickness is 7mm. The laminar cooling adopts front dispersion cooling, the cooling rate is 18℃ / S, and the steel strip temperature is reduced to 640℃ for coiling. Finally, the product performance test is carried out.

[0024] Example 3

[0025] The rolling is carried out using the traditional 2250 hot rolling production line. The slab heating temperature is 1243℃, the heating time is 50min, and the hot rolling mill is used for rolling. The finishing rolling temperature is 892℃, and the finished product thickness is 7mm. The laminar cooling adopts front dispersion cooling, the cooling rate is 19℃ / S, and the steel strip temperature is reduced to 640℃ for coiling. Finally, the product performance test is carried out.

[0026] Comparative Example 1

[0027] The smelting is carried out in a laboratory furnace. The slab heating temperature is 1240℃, the heating time is 50min, and the hot rolling mill is used for rolling. The finishing rolling temperature is 890℃, and the finished product thickness is 7mm. The laminar cooling adopts front dispersion cooling, the cooling rate is 19℃ / S, and the steel strip temperature is reduced to 625℃ for coiling. Finally, the product performance test is carried out.

[0028] Comparative Example 2

[0029] The smelting was carried out in a laboratory furnace. The slab heating temperature was 1240℃, the heating time was 51min, and the hot rolling mill was used for rolling. The finishing rolling temperature was 887℃, and the finished product thickness was 7mm. The laminar cooling adopted front dispersion cooling, the cooling rate was 18℃ / S, and the steel strip temperature was reduced to 625℃ for coiling. Finally, the product performance test was carried out.

[0030] Table 1 Chemical composition of Examples 1 to 3 of the present invention (wt%)

[0031]

[0032] The mechanical properties of the steel coils of Examples 1 to 3 of the present invention were tested, and the test results are shown in Table 2.

[0033] Table 2 Mechanical properties of the steel coils of Examples 1 to 3 of the present invention

[0034]

[0035]

[0036] It can be seen from the data in Table 2 that the mechanical properties and process properties of the weathering steel for photovoltaic brackets with good low-temperature impact toughness produced according to the method provided by the present invention meet the requirements of the agreement signed with the user.

[0037] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A method for producing weathering steel for photovoltaic brackets with good low-temperature impact toughness, characterized in that: The main process parameters are as follows: Smelting-continuous casting production process: The chemical composition of the molten steel by mass percentage is C: 0.06-0.08%, Si: 0.20-0.30%, Mn: 0.7-0.9%, P: 0.03-0.06%, S: ≤0.008%, Cu: 0.20-0.25%, Cr: 1.8-2.0%, Ni: 0.04-0.06%, Ti: 0.08-0.10%, Alt: 0.020-0.050%, and the rest is Fe and impurities; Hot rolling production process: ingot - induction heating furnace - laboratory rolling mill - laminar cooling - simulated coiling; wherein: the ingot out of the furnace temperature is 1240±20℃, the final rolling temperature of the finishing rolling is 890℃, the cooling rate is 10-20℃ / S, the hot rolled steel strip thickness is 8mm; cooling adopts laminar cooling equipment, front dispersed cooling mode, and the coiling temperature is 630±10℃.

2. The method for producing weathering steel for photovoltaic brackets with good low-temperature impact toughness according to claim 1, characterized in that: The rolling is carried out using a traditional 2250 hot rolling production line. The slab heating temperature is 1250°C, the holding time is 48 minutes, and the hot rolling mill is used for rolling. The finishing rolling temperature is 893°C, and the finished product thickness is 7mm. Laminar cooling uses front dispersed cooling with a cooling rate of 20°C / S, and the steel strip temperature is reduced to 640°C for coiling.

3. The method for producing weathering steel for photovoltaic brackets with good low-temperature impact toughness according to claim 1, characterized in that: The rolling is carried out using a traditional 2250 hot rolling production line. The slab heating temperature is 1250°C, the holding time is 50 minutes, and the hot rolling mill is used for rolling. The finishing rolling temperature is 888°C, and the finished product thickness is 7mm. Laminar cooling uses front dispersed cooling with a cooling rate of 18°C / S, and the steel strip temperature is reduced to 640°C for coiling.

4. The method for producing weathering steel for photovoltaic brackets with good low-temperature impact toughness according to claim 1, characterized in that: The rolling is carried out using the traditional 2250 hot rolling production line. The slab heating temperature is 1243°C, the heating time is 50 minutes, and the hot rolling mill is used for rolling. The finishing rolling temperature is 892°C, and the finished product thickness is 7mm. The laminar cooling adopts front dispersion cooling with a cooling rate of 19°C / S. The temperature of the steel strip is reduced to 640°C for coiling.

5. The method for producing weathering steel for photovoltaic brackets with good low-temperature impact toughness according to claim 2, characterized in that: The chemical composition of the weathering steel in mass percentage is: C: 0.07%, Si: 0.25%, Mn: 0.83%, P: 0.051%, S: 0.004%, Cu: 0.23%, Cr: 1.89%, Ni: 0.046%, Ti: 0.090%, Alt: 0.030%, and the rest is Fe and impurities.

6. The method for producing weathering steel for photovoltaic brackets with good low-temperature impact toughness according to claim 3, characterized in that: The chemical composition of the weathering steel in mass percentage is: C: 0.07%, Si: 0.25%, Mn: 0.83%, P: 0.047%, S: 0.003%, Cu: 0.23%, Cr: 1.87%, Ni: 0.052%, Ti: 0.085%, Alt: 0.031%, and the rest is Fe and impurities.

7. The method for producing weathering steel for photovoltaic support with good low-temperature impact toughness according to claim 4, characterized in that: The chemical composition of the weathering steel in mass percentage is: C: 0.07%, Si: 0.25%, Mn: 0.81%, P: 0.052%, S: 0.003%, Cu: 0.25%, Cr: 1.89%, Ni: 0.055%, Ti: 0.088%, Alt: 0.030%, and the rest is Fe and impurities.

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