JP2013199803A - Method for installing solar power generating module on building - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for installing a solar power generating module, in which reliability for corrosion resistance of entire support components is significantly improved, using components with high productivity.SOLUTION: A solar power generating module having a framework is installed on a building through support components composed of steel material. Part of the support components are covered with a cover component (A) such that the rainwater from the solar power generating module runs down to the surface of the cover component. The cover component (A) is made of a hot dip aluminized steel plate with a plate thickness t of 1 mm or less, having an aluminum plating layer of Al/0 to 12 mass% Si composition with a deposition amount of 20 g/mon a single side. The steel plate is bent to have a processing degree with a t/R of 0.33 or less, where R represents the inner bend radius at a bending part.

Description

  The present invention relates to a method of installing a photovoltaic power generation module having a frame such as an Al alloy on a roof of a building.

  In recent years, an increasing number of cases employ a power generation system in which a photovoltaic power generation module is installed on the rooftop of a building such as a house or a building. Fig. 1 and Fig. 3 shows the component structure when installing the photovoltaic module shown in the "Residential photovoltaic system design and construction guidelines" compiled by the New Energy Foundation. An example is shown schematically. A photovoltaic power generation module (hereinafter, simply referred to as “module”) 12 is a panel in which solar cells such as polycrystalline silicon are arranged, and has a frame frame 11 around it. The frame 11 is often made of an Al alloy member, and usually has an anodized film or a coating film formed on the surface thereof. When installing the module 12 in a building, it is common to interpose a metal mount between the building and the module 12 and fix the module 12 to the building via the mount.

  In the example of FIG. 3, the photovoltaic power generation module 12 is installed on the inclined roof surface 10 via a gantry formed by connecting a horizontal beam 21 and a vertical beam 22. In this case, the module 12 is disposed between the horizontal rail 21 and the horizontal rail 21, and is fixed by using the inter-module cover 32 and the fastening bracket 31. In the present specification, a cover that is attached to the module 12 disposed at the end and is not between the modules 12 is also referred to as an inter-module cover 32 for convenience. The horizontal beam 21 is fixed to the vertical beam 22 by a fastening bracket 31. The vertical rail 22 is fixed to the roof surface 10 with a support metal fitting 33. Moreover, in the example of FIG. 1, the module is installed through the mount frame which attached the slope to the land roof with almost no inclination. In this case, the gantry is constructed by attaching a stay 23 and reinforcing members such as braces as needed in addition to members corresponding to the horizontal beam 21 or the vertical beam 22.

  The gantry has a structure in which members that handle the load of the photovoltaic power generation module, such as the horizontal beam 21 and the vertical beam 22, are coupled by a fastener, a bolt, a nut, a washer, and the like. Among the members constituting the gantry, the horizontal beam 21, the vertical beam 22, the stay 23, and the support fitting 33 are members responsible for the module load. Such a member is referred to as a “support member” in this specification, and is distinguished from a coupling member such as a fastening bracket, a bolt, a nut, and a washer, and a reinforcing member such as a brace. In general, the support member that constitutes the base of the photovoltaic power generation module is formed of a processed member having a constant cross-sectional shape in the longitudinal direction, excluding the support fitting.

  A frame frame of the photovoltaic power generation module (hereinafter simply referred to as “frame frame”) and a support member (hereinafter also simply referred to as “support member”) constituting the gantry are grounded by a ground wire. Therefore, although the frame frame and the support member are in an electrically connected state, the frame frame made of Al alloy is usually covered with an anodized film or a coating and the surface is in an insulating state. In general, electrical connection is ensured by connecting the Al alloy substrate and the metal of the support member with a cable.

  Conventionally, as materials for peripheral members (support members, cover between modules, fastening brackets, etc.) of a photovoltaic power generation module, doub-zipped Zn-plated steel material, stainless steel material, Al alloy material or the like has been used. In the case of the dobbed Zn-plated steel material, since the member after the forming process is subjected to Zn plating by immersing it in a hot-dip Zn plating bath, for example, it is also plated on the cut end face as shown by reference numeral 40 in FIG. A layer is formed.

  On the other hand, Zn—Al—Mg based plated steel sheets (for example, Patent Documents 1 and 2) have been used in various fields as high corrosion resistance materials instead of Zn plated steel sheets. Further, in applications such as exhaust gas passage members, Al-based plated stainless steel plates having excellent heat resistance and corrosion resistance are used (for example, Patent Documents 3 and 4).

In addition, as described in Patent Document 5, the inventor is a steel plate containing 7 mass% or more of Cr, and an Al-based plating layer having an Al-3 to 12 mass% Si composition is 20 g / per side. An invention was made in which a molten Al-based plated steel sheet formed with an adhesion amount of m ² or more was used as the support member.

Japanese Patent No. 3179401 Japanese Patent No. 3149129 Japanese Patent No. 2132539 Japanese Patent Application Laid-Open No. 07-233451 JP 2009-33066 A

  The conventional support member has the following problems.

[Problems of Dobbed Zn-plated steel]
The photovoltaic power generation module is installed with a gradient. The rain that has fallen on the module surface flows along the surface of the module and the cover of the module according to the gradient, and a part of the rain flows down along the surface of the support member and the surface of the fastener. Therefore, a flow path in which rainwater concentrates is formed in these members. In these parts, the consumption of the plated layer of the zinc-plated Zn plating material is significantly faster than the general exposure environment, and the durability is often insufficient. This is because, in a general exposure environment, the corrosion product generated on the surface of the plating layer becomes a protective film to suppress the subsequent corrosion, whereas the generated corrosion product is washed away at the location where it becomes a rainwater flow path. This is probably because the protective film cannot be formed.

  In addition, if there is a place where rainwater stays on the surface of these members, the staying water may be heated in the summer to become hot water of 50 to 60 ° C. In particular, a gap is formed at the contact portion between the frame frame and the support member so that rainwater tends to stay, and corrosion is accelerated by contact with hot water.

  Further, although the surface of the frame frame made of Al alloy is generally insulated by a coating film or the like, surface flaws may occur at the installation position on the support member or the like, and the Al alloy may be exposed. The Al alloy may be slightly exposed even at the ground cable connection point. When the Al alloy is exposed to the rainwater and an electrical circuit is formed through the rainwater between the Zn plating layer of the support member to which the frame frame is attached, the natural potential is “base” against Al. Corrosion is promoted in the Zn plating layer (dissimilar metal contact corrosion).

  In addition, the dobbed Zn-plated steel material is manufactured by immersing the molded member in a high-temperature plating bath, so it is easily affected by thermal strain. For long materials such as “bars” used as support members, the dimensions are high. It is difficult to obtain accuracy. There is also a problem that the plating work after the forming process has poor productivity.

  If the Zn—Al—Mg based plated steel material having excellent corrosion resistance shown in Patent Documents 1 and 2 is substituted, the durability is improved. However, the Zn—Al—Mg-based plating layer is still “base” with respect to Al, and is not a drastic measure for dissimilar metal contact corrosion.

[Problems with stainless steel]
As described above, the support member and the fastening member of the photovoltaic power generation module are exposed to rainwater and, in some cases, come into contact with high-temperature stagnant water. In order to ensure sufficient corrosion resistance by applying stainless steel materials for such applications, it is necessary to apply stainless steels with relatively high corrosion resistance grades, such as steel types with a high Cr content and steel types containing Ni and Mo. There is. Therefore, the member cost is inevitably increased.

  In addition, when a stainless steel support member or fastener is used, a circuit through rainwater such as that described above is formed between the exposed portion of the Al alloy substrate that is generated at a spotted portion of the frame frame, etc. Different metal contact corrosion occurs in the Al alloy which is “base” in terms of potential with respect to stainless steel.

[Problems of Al-based alloy materials]
If the support member and the cover between modules are made of an Al alloy, the above-mentioned problem of dissimilar metal contact corrosion can be avoided. However, in order to configure these members with an Al alloy, it is necessary to increase the thickness from the viewpoint of strength. Such an Al alloy member is generally made by extrusion molding. When considering installation on various roof surfaces, various shapes corresponding to each roof are also required for support members, etc., but it is difficult to prepare various shapes of members because of extrusion molding, and design The degree of freedom is considerably restricted.

[Problems of Al-Si plating Cr-containing steel]
When the above-described Al-Si-based plated Cr-containing steel material invented by the present inventor is used as a support member, the above-mentioned doppled Zn-plated steel material, stainless steel material, Al-based alloy material or the like is used as a support member. The problem of was wiped out. On the other hand, locations where corrosion resistance problems occur in support members using dobbing Zn-plated steel materials or stainless steel materials are limited to locations where they come into contact with the frame frame or channels where rainwater from the module surface is concentrated. Is a small proportion of the entire support member. Applying Al-Si-plated Cr-containing steel just to ensure corrosion resistance in such locations means that the majority of the support members will have excessive quality beyond what is needed, increasing the cost of the components It was connected to.

  In view of such a current situation, the present invention provides a method for installing a photovoltaic power generation module that improves the corrosion resistance of places where improvement in corrosion resistance is necessary, and the reliability of the support member as a whole is significantly improved. The purpose is to do.

In order to achieve the above object, the present invention provides a solar power generation module having a frame frame on a building through a support member made of a steel material. Provided is a method of installing a photovoltaic power generation module on a building so that the flow of rainwater from the photovoltaic power generation module flows down to the surface of the cover member by covering with a member.
(A) Cover member: bending a hot-dip Al-based plated steel sheet having a thickness t of 1 mm or less in which an Al-based plating layer having an Al-0 to 12% by mass Si composition is formed with an adhesion amount of 20 g / m ² or more per side Cover member formed by bending at a working degree such that t / R is 0.33 or less when the bending radius inside the portion is R

In addition, the present invention provides a solar power generation module having a frame frame on a building through a support member made of steel, and by covering a part of the support member with a cover member (B) below, Provided is a method for installing a photovoltaic power generation module on a building, in which the flow of rainwater from the photovoltaic power generation module flows down to the surface of the cover member.
(B) Cover member: The thickness t of an Al-based plating layer having an Al-0 to 12% by mass Si composition formed with an adhesion amount of 20 g / m ² or more per side is 1 mm or less, and the hardness of the plating layer A cover member obtained by bending a hot-dip Al-based plated steel sheet having an (HV) of 60 or less with a working degree such that t / R is 1 or less, where R is the bending radius inside the bent portion.

  In any of the present inventions described above, the steel material serving as the support member may be a hot-dip Zn-based plated steel plate using a normal steel plate as a base material. In the plating layer, Al and Mg may be contained in the range of Al: 0 to 60% by mass and Mg: 0 to 10% by mass, respectively, and further Si may be contained in the range of 0 to 2% by mass. It doesn't matter.

The “part of the support member” covered with the cover member is preferably a location including a location where the support member contacts the frame.
Note that “covering a part of the support member with the cover member” includes placing the cover member on a part of the support member, but the support member and the frame at the contact point between the support member and the frame frame. It is preferable to “cover a part of the support member with the cover member” by interposing the cover member between the frame and the frame. In this case, it is more preferable that three layers of the frame frame, the cover member, and the support member are contacted and laminated to form an electrical connection with each other.

  Here, “building” means a structure that is fixed on the land, but the foundation in the case of installing a photovoltaic power generation module on the ground is also treated as a building here. The “Al alloy” is an alloy in which at least Al occupies 90% by mass or more, and specifically, an alloy in a range defined in JIS H4000 can be selected. The “hot-dipped Al-based plated steel sheet” in (A) and (B) includes those subjected to chemical conversion treatment or coating after hot-dipping.

  According to the present invention, the problem related to corrosion resistance caused by installing a photovoltaic power generation module having a frame in an environment exposed to rain (Zn plating promoted because a protective corrosion product is not generated) Corrosion of members, contact corrosion of dissimilar metals with Al alloy) is eliminated. Further, it is no longer necessary to manufacture the peripheral members of the photovoltaic power generation module by “dough soaking plating”, thereby improving productivity and improving dimensional accuracy. Therefore, the present invention provides a significant improvement in durability as a whole while suppressing an increase in cost in a photovoltaic power generation system using an existing photovoltaic power generation module.

Further, the portion where rainwater concentrates and flows down from the photovoltaic power generation module is covered with the cover member, so that rainwater does not concentrate directly on the surface of the support member and the corrosion of the support member is prevented. Therefore, a hot-dip Zn-based plated steel sheet based on a plain steel sheet that is superior in terms of material cost, processing cost, and design flexibility can be used as the steel material for the support member.
Furthermore, when the cover member is corroded due to use over a long period of time, it is possible to return to the initial installation state at low cost at an early stage by updating only the cover member. As a result, every time the cover member corrodes due to long-term use, it is possible to return to the original installation state repeatedly by renewing only the cover member, and the initial support member installed in the building can be restored over a long period of time. It can be used as it is.

The figure which showed typically an example of the member structure in the case of installing a solar power generation module in a flat roof surface. The figure which is a case where this invention is applied to the structure of FIG. 1, Comprising: The figure which showed typically an example of the attachment position of the cover member attached to a vertical cross, and the shape of a cover member. The figure which showed typically an example of the member structure in the case of installing a photovoltaic power generation module in the inclined roof surface of a building. The figure which was a case where this invention was applied to the structure of FIG. 3, Comprising: The figure which showed typically an example of the attachment position of the cover member attached to a crosspiece, and the shape of a cover member.

[Fused Al-based plating layer]
By using the cover member to which the Al-based plating layer is applied, the corrosion resistance of the plating surface can be improved at a location where the rain that has fallen on the module surface is concentrated and where rainwater stays. This is presumably because the oxide film formed on the plating surface stably exists as a protective film in these environments. Further, when Al-based plating is used for the cover member, it is possible to prevent dissimilar metal contact corrosion with the Al alloy of the frame frame.

In the present invention, a hot-dip Al-based plated steel sheet in which an Al-based plated layer having an Al-0 to 12% by mass Si composition is formed with a thickness of 20 g / m ² or more per side is used as the cover member. The “Al-0 to 12% by mass Si composition” is a plating layer formed by passing a base steel sheet through a molten Al plating bath having an Si content of 0 to 12% by mass.

  The reasons for adding Si are mainly (i) to lower the temperature of the plating bath by lowering the melting point, and (ii) to suppress the formation of a brittle alloy layer formed between the Al plating layer and the steel substrate. It is. In order to produce this merit, the Si content in the Al bath is preferably 3% by mass or more. Moreover, it becomes a eutectic composition when the Si content is around 12% by mass, and the melting point is most lowered. Therefore, adding a larger amount of Si is not effective in lowering the bath temperature. Rather, increasing the Si content leads to a decrease in the corrosion resistance of the plating layer, so care must be taken. That is, corrosion of the Al-based plating layer containing Si in flowing water or staying water proceeds from Al around the Si precipitates present on the surface of the plating layer. When Si is excessively contained exceeding 12% by mass, Si precipitates existing on the surface increase, the starting point of corrosion increases, and the corrosion resistance decreases. From the viewpoint of corrosion resistance, the Si content in the plating bath is desirably in the range of 12% by mass or less, and more preferably 11% by mass or less. Further, if the Si content exceeds 12% by mass, massive precipitates are deposited and the workability is impaired. Therefore, from the viewpoint of workability, the Si content is preferably within the range of 12% by mass or less. .

  Since the plating bath contains elements inevitably mixed from the base steel plate and the raw material of the plating bath, the plating bath composition is “Si: 0 to 12% by mass, balance Al and inevitable impurities”. Can be displayed. Further, the plating bath may further contain one or more of Ti, B, Sr, Cr, Mg, Zr, Ca, and Mn in a total range of 1% or less. The plating bath composition in this case is “Si: 0 to 12% by mass, containing one or more of Ti, B, Sr, Cr, Mg, Zr, Ca, and Mn in a total range of 1% or less, and the balance It consists of Al and inevitable impurities ”.

If the thickness of the Al plating layer of the cover member is thin, pinhole plating is likely to occur, and the steel substrate is likely to be exposed at places where the plating layer is wrinkled during molding or on-site construction. Since the normal steel base is “base” in terms of potential with respect to the Al plating layer, red rust is generated at the exposed portions of the steel base. In order to prevent these problems, as a result of various studies, it is necessary to secure an adhesion amount of the Al-based plating layer of the cover member of 20 g / m ² or more per side.

  By setting the plate thickness of the cover member to 1 mm or less, the occurrence of red rust from the cut end surface that is “base” in terms of potential with respect to the Al plating layer is less noticeable. Further, when a Zn-based plated steel plate is used for the support member, the sacrificial anticorrosive action of the Zn-based plated layer also works, so that red rust on the cut end surface of the cover member is not noticeable.

  T / R to prevent cracking of the plating layer at the outer bent portion and to suppress the exposure of the steel substrate when bending the Al-plated steel plate of thickness t with the bending radius inside the bent portion being R. Must be 0.33 or less. Further, when the Al plating layer is softened so that the hardness (HV) is 60 or less, the plating layer is not cracked even by a more severe bending process, and t / R can be expanded to a range of 1 or less. .

  The hardness (HV) of the Al plating layer can be reduced to 60 or less by, for example, heat-treating at a temperature range of 250 to 500 ° C. for 5 to 50 hours after Al plating. When the heating temperature does not reach 250 ° C, the hardness of the Al plating layer does not become 60 or less. Conversely, heating at a temperature exceeding 500 ° C saturates the softening effect and forms at the interface between the plating layer and the steel substrate. The grown alloy layer grows and, on the contrary, impairs workability. If the heating time is less than 5 hours, the hardness of the Al plating layer does not become 60 or less, and conversely, even if heating is performed for more than 50 hours, the softening effect is saturated.

The reason why the Al plating layer can be softened by heat treatment under appropriate conditions is presumed as follows.
When a molten Al-based plated steel sheet is produced using a plating bath containing Si, the Al dendrite of the plating layer becomes a solid solution of Si in a supersaturated state in the process of solidifying the plating layer after being pulled up from the plating bath. By heat-treating such a plating layer under appropriate conditions, Si that has been dissolved in supersaturation is precipitated in a spheroidized state. On the other hand, Al dendrite is softened by discharging Si that was dissolved in supersaturation. Therefore, by performing heat treatment under appropriate conditions, even when bending with a high degree of work is performed, the plating layer is cracked at the outer bent portion and the steel substrate is prevented from being exposed, and the occurrence of red rust is reduced. It is.
It is preferable for the present invention that the Si discharged and precipitated from the Al dendrite takes a spherical shape. When strain due to bending is applied to the plating layer, it is difficult to accumulate strain around the spheroidized Si, so that the plating layer does not crack and can endure bending with a higher degree of processing. is there.

[Example 1]
(Support member)
As a supporting member (a member corresponding to reference numerals 21 to 23 in FIG. 1), a molten Zn-6 mass% Al-3 mass% Mg composition in which the plate thickness is 1.6 mm and the plating adhesion amount per side is 150 g / m ² ( A known inorganic chromium-free chemical conversion treatment (Ti-Mg system) was applied to a plated plain steel plate of Zn-6Al-3Mg and processed into a C-type channel. The inner bending radius of the bent portion is 1.6 mm (the outer bent radius is 3.2 mm), and in these members, the plating layer is cracked on the outer surface of the bent portion and the steel substrate is exposed.

[Cover member]
Cold-rolled steel sheets having various thicknesses were prepared, and using these as base materials, hot-dip plating was performed in a continuous hot-plating line using a plating bath selected from the plating baths shown in Table 1. The composition of the hot dipped layer almost reflects the composition of the plating bath. The plating adhesion amount control was performed by a general gas wiping method (wiping gas was air), and both surfaces were adjusted to the same adhesion amount. After the hot dip plating, a known organic resin coating was applied.

  By processing the plated steel sheet after the post-treatment, a cover member covering the vertical rail as shown in FIG. 2 was produced. The bending degree of the bent part was changed variously (see Table 2).

[Solar power generation module]
A commercially available solar power generation module having an Al alloy frame (JIS H8602: anodized composite film) was prepared.
[Installation of photovoltaic modules]
The building where the module is installed is a flat roof. A gantry corresponding to FIG. 1 was prepared using the support member and fixed to a flat roof, and a module was attached to the gantry. The frame frame, the horizontal beam, and the vertical beam were electrically connected by a ground wire cable and grounded. The installation location was the coastal industrial area of Sakai City, Osaka Prefecture.
In this gantry, the location where rainwater flows from the module into the vertical rail becomes the rainwater flow path or the rainwater retention part. A cover member was interposed between the frame and the vertical beam so as to cover the upper surface and side surfaces of the beam.

[Corrosion resistance evaluation]
Corrosion condition and bending part of plating layer at the time when two years have passed since the installation of the cover member covering the vertical beam attached to the rainwater flow path and the part that becomes the retention part and the vertical beam covered by the cover member And the occurrence of red rust on the cut end face was evaluated. The evaluation method and evaluation criteria are as follows.
(Plating layer corrosion status)
Cut out the sample from the cover member, observe the cross section of the plating layer with an optical microscope, calculate the average thickness of the corroded part compared with the original plating thickness, and multiply the density of the plating layer to obtain the amount of corrosion The evaluation was based on the following criteria, and an evaluation of ○ or higher was determined to be acceptable.
A: Corrosion amount is less than 1 g / m ² ○: Corrosion amount is 1 g / m ² or more and less than 10 g / m ² Δ: Corrosion amount is 10 g / m ² or more and less than 30 g / m ² ×: Corrosion amount is 30 g / m ² or more

(Red rust occurrence status)
The occurrence of red rust in the bent parts (A and B parts in FIG. 2) and the edge of the cover member (C part in FIG. 2) was visually observed and evaluated according to the following criteria.
A: No occurrence of red rust O: Almost no red rust is observed Δ: A slight amount of red rust is generated x: A large amount of red rust is generated and spreads around the results Table 2 summarizes the results.

As can be seen from Table 2, in an example of the present invention using an Al-based plated steel sheet having an Al-0 to 12% by mass Si composition and using a cover member that has been subjected to a bending degree t / R of 0.33 or less, The plating layer is not cracked not only on the flat part of the cover member, but also on the outer surface of the bent part (A part) between the flat parts and the bent part (B part) of the folded end face in the longitudinal direction. Good corrosion resistance was exhibited. On the other hand, No. 113 which is a comparative example has a portion where the bending degree t / R exceeds 0.33 in the B portion of the cover member, and 104 and 112 in the A portion and B portion of the cover member, Since the outer surface of the plating layer was cracked at the bent portion, red rust was generated from the steel substrate. No. 107 did not form a fold in the B part and was left in a cut state, so rainwater stayed here and red rust was noticeable. Further, in Comparative Example 108, since the amount of plating adhered per one side of the cover member was as small as less than 20 g / m ^2, pinholes were generated, and red rust from the steel substrate was generated in a spot shape.

The fork (C part), which is a cut surface cut in a direction perpendicular to the longitudinal direction of the cover member, is a place where rainwater does not stay and the sacrificial anticorrosive action due to the Zn-Al-Mg-based plating of the gantry works. Red rust is not observed when the plate thickness is up to 0.5 mm, and almost no red rust is observed up to 1.0 mm or less, but red rust is slightly observed when the plate thickness is as thick as 1.2 mm (Comparative Example No. 112). And occurred. In Comparative Example 115, since the Si concentration in the plating layer exceeded 12 mass% and the bending workability was poor, red rust was generated on the outer surface of the bending portion although the bending workability was appropriate. In Comparative Example 116, since the plating composition was Zn-55 mass% Al, the corrosion resistance was insufficient, and after the corrosion of the plating layer proceeded, red rust was generated from the bent portion and the end face.
In addition, in the case of any of the comparative examples as well as the examples of the present invention, no corrosion was observed on the support member at the portion covered with the cover member.

[Example 2] (Example of covering a horizontal rail with a cover member subjected to bending after the plating layer is softened)
(Support member)
The supporting member (members corresponding to reference numerals 21 and 22 in FIG. 3) is known to a hot-dip Zn-6Al-3Mg plated ordinary steel sheet having a plate thickness of 1.6 mm and a plating adhesion amount per side of 150 g / m ² . An inorganic chromium-free chemical conversion treatment (Ti-Mg) and processed into a C-type channel was used. The inner bend radius of the bent portion is 0.4 mm (the outer bend radius is 2.0 mm). In these members, the plating layer is cracked on the outer surface of the bent portion, and the steel substrate is exposed.

[Cover member]
Cold-rolled steel sheets having a plate thickness of 0.5 mm were prepared, and using these as base materials, hot-dip plating was performed in a continuous hot-dip plating line using a plating bath selected from the plating baths shown in Table 1. The composition of the hot dipped layer almost reflects the composition of the plating bath. The plating adhesion amount was controlled by a general gas wiping method (wiping gas was air), and the adhesion amount per side was adjusted to 40 g / m ² . After plating, a known inorganic chromium-free chemical conversion treatment (Ti-V system) was performed. Thereafter, heat treatment was performed under various conditions in an air atmosphere.
As for the hardness of the plating layer, the cross-section Vickers hardness was measured at a load of 1 gf.
By processing the plated steel sheet after the heat treatment, a cover member covering the horizontal rail as shown in FIG. 4 was produced. The bending degree of the bent portion was variously changed (see Table 3).

[Solar power generation module]
The same photovoltaic module as Example 1 was prepared.
[Installation of photovoltaic modules]
The building where the module is installed is an inclined roof, and a solar power generation module is fixed to the side rail. Using the support member, a frame corresponding to FIG. 3 was prepared and a module was attached. The part that becomes the flow path of the rainwater or the part where it stays is the place where the rainwater that has fallen on the module surface flows out from the corner of the frame of the module to the horizontal rail. A cover member was attached between the frame and the horizontal rail so as to cover the top and side surfaces of the rail (see FIG. 4). The installation location is the urban area of Sakai City, Osaka Prefecture.

[Corrosion resistance evaluation]
The corrosion resistance evaluation was performed in the same manner as in Example 1 for the cover member covering the horizontal rail attached to the rainwater flow path and the portion serving as the retention portion and the horizontal rail covered by the cover member. The results are summarized in Table 3.

As can be seen from Table 3, an Al-plated steel sheet having an Al-0 to 12% by mass Si composition with a hardness (HV) of the plating layer of 60 or less is used, and a bending process degree t / R is 1 or less. In the example of the present invention, not only the flat part of the cover member but also the outer side surface of the bent part (A part) between the flat part and the bent part (B part) of the folded end face in the longitudinal direction. The plating layer was not broken and showed good corrosion resistance. On the other hand, in Comparative Examples 203 and 209, the hardness of the plating layer exceeded 60, and even when the bending degree t / R was 1 or less, the plating layer was cracked on the outer surface of the bending portion and red rust was generated from the steel substrate. .
In No. 206, although the hardness of the plating layer was an appropriate condition, red rust occurred in the processed portion where the bending degree t / R was 2. The small edge (part C) is a place where rainwater does not stay, and the plate thickness is as thin as 0.5 mm, and the sacrificial anticorrosive action by the Zn—Al—Mg-based plating of the gantry works, so that no red rust occurred.
In addition, in the case of any of the comparative examples as well as the examples of the present invention, no corrosion was observed on the support member at the portion covered with the cover member.

DESCRIPTION OF SYMBOLS 10 Roof surface 11 Frame frame 12 Solar power generation module 21 Horizontal beam 22 Vertical beam 23 Stay 31 Fastening bracket 32 Cover between modules 33 Support metal fitting 40 Cutting end surface 41 Cover member

Claims (3)

When installing a photovoltaic power generation module having a frame frame on a building via a support member made of steel, a part of the support member is covered with a cover member of the following (A) from the photovoltaic power generation module. A method for installing a photovoltaic power generation module on a building, wherein the rainwater flows down to the surface of the cover member.
(A) Cover member: bending a hot-dip Al-based plated steel sheet having a thickness t of 1 mm or less in which an Al-based plating layer having an Al-0 to 12% by mass Si composition is formed with an adhesion amount of 20 g / m ² or more per side Cover member formed by bending at a working degree such that t / R is 0.33 or less when the bending radius inside the portion is R When installing a photovoltaic power generation module having a frame frame on a building via a support member made of a steel material, a part of the support member is covered with a cover member (B) below from the photovoltaic power generation module. A method for installing a photovoltaic power generation module on a building, wherein the rainwater flows down to the surface of the cover member.
(B) Cover member: The thickness t of an Al-based plating layer having an Al-0 to 12% by mass Si composition formed with an adhesion amount of 20 g / m ² or more per side is 1 mm or less, and the hardness of the plating layer A cover member obtained by bending a hot-dip Al-based plated steel sheet having an (HV) of 60 or less with a working degree such that t / R is 1 or less, where R is the bending radius inside the bent portion.   The installation method according to claim 1 or 2, wherein the steel material is a hot-dip Zn-based plated steel plate based on a plain steel plate.

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