Precoated member and curing method thereof

Abstract

To provide a pre-coating member and its curing method capable of preventing contamination of a fire-resistant paint coating surface due to rust fluid without leaving foreign matters which inhibit stud welding.SOLUTION: A pre-coating member 10 with a steel member 14 and a fire-resistant paint 20 provided on the surface of the steel member 14 via an undercoat layer 18 is further provided with a masking tape 26 peelable against the part of the surface of the steel member 14 including a planned welding point P. The undercoat layer 18 is preferably provided on the surface of the steel member 14 to cover the masking tape 26 provided on the surface of the steel member 14.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a precoated member produced by pre-painting a fire-resistant paint or the like on a steel frame member in a factory or the like, and a method for curing the precoated member. [Background technology]

[0002] Conventionally, when a structure using steel materials, such as a steel-frame building, is exposed to a fire, the strength and rigidity of the steel materials decrease due to the rise in temperature, and there is a risk that the structure may collapse. Therefore, fire-resistant coating is applied to the beams and columns of steel-framed structures to suppress the rise in temperature due to fire heating (for example, see Patent Document 1).

[0003] One type of fire-resistant coating material is a fire-resistant paint whose main component is ammonium polyphosphate. When exposed to heat during a fire, fire-resistant paint begins to foam at around 200-300℃, expanding 20-30 times in size to form an insulating layer and suppress the temperature rise of steel materials.

[0004] It is common for steel beams to have stud bolts welded to the top surface of the beam's top flange in order to integrate them with the concrete slab that will be installed after the beam is erected. Even if a steel beam that has been pre-painted with fire-resistant paint in a factory or the like (hereinafter referred to as a pre-coated beam) is transported to a construction site and erected there, a stud bolt will be welded to the top surface of the pre-coated beam's top flange in order to integrate the pre-coated beam with the concrete slab that will be installed later. When welding the stud bolts, there must be no foreign matter between the weld end of the stud bolt and the welded surface of the steel beam (top surface of the top flange) that would hinder the welding. For this reason, it is common for the top surface of the top flange of the steel beam not to be coated with an anti-rust paint (primer paint) and for the steel material to be exposed.

[0005] With regard to the technique of stud welding to a component to which fire-resistant paint has previously been applied, the present patent applicant has already proposed a fire-resistant component described in Patent Document 2. The fire-resistant component described in Patent Document 2 comprises a steel material, a foaming fire-resistant paint that is applied to the surface of the steel material and foams at a predetermined foaming temperature when heated, and a stud welded to the non-fire-resistant paint-coated surface of the steel material by stud welding in which the temperature of the steel material is controlled to be equal to or lower than the foaming temperature of the fire-resistant paint. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 2-308046 [Patent Document 2] Patent application No. 2020-082128 (currently unpublished) Summary of the Invention [Problem to be solved by the invention]

[0007] Incidentally, after being painted in the factory, the above-mentioned precoated beams are exposed to water, such as rainwater, during outdoor storage (if stored outdoors), during transportation, and until a concrete slab is constructed on the precoated beam. Therefore, if the upper surface of the upper flange is not coated with a rust-preventive coating, the rust that occurs on the upper surface of the upper flange will turn into rust fluid when exposed to rainwater and other water, and run down onto the fire-resistant paint surface of the precoated beam, contaminating the painted surface (finished surface). For appearance reasons, the rust fluid must be wiped off from the contaminated painted surface, but if the rust fluid cannot be wiped off, a top coat must be applied again.

[0008] In this way, if rust fluid adheres to the precoated beam, the fireproof coating surface must be cleaned on-site or another top coat must be applied. This creates a problem in that the greatest advantage of factory painting (precoating), which is the reduction in labor required for on-site fireproof coating work, is not fully achieved. Also, if an anti-rust paint is applied to the top flange to prevent rust from forming on the top flange, this will prevent rust from forming, but it will require the effort of removing the anti-rust paint when welding the studs, which is contrary to the labor savings mentioned above.

[0009] The present invention has been made in consideration of the above, and has an object to provide a precoated member and a curing method thereof that does not leave any foreign matter that would impede stud welding and that can prevent contamination of the fire-resistant paint surface by rust fluid. [Means for solving the problem]

[0010] In order to solve the above-mentioned problems and achieve the object, the precoat member of the present invention is a precoat member comprising a steel member and a fire-resistant paint applied to the surface of the steel member via a primer layer, and is characterized in that it further comprises masking tape removably applied to a portion of the surface of the steel member that includes a planned welding location.

[0011] Furthermore, another precoat member according to the present invention is characterized in that, in the above-mentioned invention, the undercoat layer is provided on the surface of the steel frame member so as to cover the masking tape provided on the surface of the steel frame member.

[0012] Another precoat member according to the present invention, in the above-mentioned invention, has a base coating layer of fire-resistant paint applied on an undercoat layer, an intermediate coating layer applied on this base coating layer, and a top coating layer applied on this intermediate coating layer, and is characterized in that the intermediate coating layer and the top coating layer cover the ends of the base coating layer applied on the end face of the steel frame member and are cornered along the corners of the end face, and are applied on the surface of the steel frame member for a predetermined length from these corners.

[0013] In addition, the method for curing a precoated member according to the present invention is a method for curing a precoated member comprising a steel member and a fire-resistant paint applied to the surface of the steel member via a primer layer, and is characterized in that masking tape is removably attached to a portion of the surface of the steel member including the planned welding locations, an primer layer is then applied to the surface of the steel member, and the masking tape is peeled off from the surface of the steel member immediately before welding, thereby enabling welding to the planned welding locations.

[0014] Another precoat member curing method according to the present invention is characterized in that, in the above-mentioned invention, masking tape is removably attached to a portion of the surface of a steel frame member that includes a planned welding location, and then a primer layer is provided on the surface of the steel frame member including the upper surface of the masking tape, and the masking tape is peeled off from the surface of the steel frame member together with the primer layer immediately before welding, thereby enabling welding to the planned welding location. Effect of the Invention

[0015] The precoat member of the present invention is a precoat member comprising a steel member and a fire-resistant paint applied to the surface of the steel member via a primer layer, and further comprises masking tape that is removably applied to the portion of the surface of the steel member that includes the planned welding locations. This has the effect of preventing contamination of the fire-resistant paint surface by rust fluid and not leaving behind any foreign matter that may hinder stud welding.

[0016] In addition, according to another precoat member of the present invention, the undercoat layer is applied to the surface of the steel frame member so as to cover the masking tape applied to the surface of the steel frame member, so that the masking tape and the undercoat layer become integrated to increase the tensile strength, thereby achieving the effect of allowing the masking tape to be easily peeled off without cutting.

[0017] Another precoat member according to the present invention has a base coating layer of fire-resistant paint applied on the undercoat layer, an intermediate coating layer applied on the base coating layer, and a top coating layer applied on the intermediate coating layer, and the intermediate coating layer and the top coating layer cover the end of the base coating layer applied on the small end surface of the steel frame member, are cornered along the corner of the small end surface, and are applied on the surface of the steel frame member for a predetermined length from the corner, so that the base coating layer of fire-resistant paint, which is weak against water and may cause swelling when it absorbs water, can be appropriately protected by the intermediate coating layer and the top coating layer. This has the effect of preventing the components of the fire-resistant paint (e.g., ammonium polyphosphate) from leaching out, and preventing a decrease in fire resistance.

[0018] Furthermore, according to the method for curing a precoated member of the present invention, there is provided a method for curing a precoated member comprising a steel member and a fire-resistant paint applied to the surface of the steel member via a primer layer, in which masking tape is removably attached to the portion of the surface of the steel member including the planned welding locations, and then a primer layer is applied to the surface of the steel member, and the masking tape is peeled off from the surface of the steel member immediately before welding, thereby enabling welding to be performed at the planned welding locations. This has the effect of preventing contamination of the fire-resistant paint surface by rust fluid and leaving no foreign matter that would hinder stud welding.

[0019] Furthermore, according to another method of curing a precoated member of the present invention, a masking tape is removably attached to a portion of the surface of a steel frame member including the areas to be welded, and then a primer layer is provided on the surface of the steel frame member including the top surface of the masking tape. Immediately before welding, the masking tape is peeled off from the surface of the steel frame member together with the primer layer, thereby enabling welding to be performed at the areas to be welded. As a result, the masking tape and the primer layer become integrated together, increasing the tensile strength, and this has the effect of allowing the masking tape to be easily peeled off without cutting. [Brief description of the drawings]

[0020] [Figure 1] FIG. 1 is a cross-sectional view showing an embodiment of a precoat member and a method for curing the same according to the present invention. [Diagram 2]FIG. 2 is a cross-sectional view showing an embodiment of a precoat member and a method for curing the same according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of a precoat member and a preservation method thereof according to the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to these preferred embodiments.

[0022] As shown in Fig. 1, the precoated member 10 according to this embodiment is made of an H-shaped steel (steel member) having a web 12, an upper flange 14, and a lower flange 16. This precoated member 10 is assumed to be a precoated beam in which a fire-resistant paint is applied to a steel beam in advance at a factory or the like.

[0023] On the surface of the precoat member 10, an undercoat layer 18, a base coating layer 20, an intermediate coating layer 22, and a top coating layer 24 are laminated in this order. More specifically, the undercoat layer 18, the base coating layer 20, the intermediate coating layer 22, and the top coating layer 24 are laminated on the surface of the web 12 and the lower flange 16, and on a part of the lower surface, the fore-edge surface, and the upper surface of the upper flange 14. The intermediate coating layer 22 and the top coating layer 24 are rolled inward from the fore-edge surface by a predetermined length D (for example, 10 mm or more) at the upper end of the fore-edge of the upper flange 14. In other words, the intermediate coating layer 22 and the top coating layer 24 cover the end of the base coating layer 20 provided on the fore-edge surface of the upper flange 14, are cornered along the corner of the fore-edge surface, and are provided on the upper surface of the upper flange 14 by a predetermined length D from the corner. This allows the main coating layer 20 of the fire-resistant paint, which is vulnerable to water and may blister when it absorbs water, to be adequately protected by the intermediate coating layer 22 and the top coating layer 24. This prevents the components of the fire-resistant paint (ammonium polyphosphate) from leaching out, and prevents a decrease in fire resistance.

[0024] Only masking tape 26 and undercoat layer 18 are provided on the central side of the upper surface of upper flange 14. Masking tape 26 is provided removably on a portion including planned welding location P of a stud bolt set at the central position of the upper surface of upper flange 14. Undercoat layer 18 is provided on the entire upper surface of upper flange 14 to which masking tape 26 is attached.

[0025] The undercoat layer 18 is a thin coating layer formed by a primer for fire-resistant paint, and has a rust-preventing function for steel materials. For this undercoat, for example, a primer mainly made of epoxy resin-based paint (for example, SK Taikacoat primer (manufactured by SK Chemical Co., Ltd.)) can be used.

[0026] The base coating layer 20 is a thin coating layer formed by the base of a fire-resistant paint. For example, a foaming fire-resistant material that foams at a predetermined temperature range when heated to suppress the temperature rise of the steel material can be used as the fire-resistant paint. For example, an example of such a fire-resistant paint is a fire-resistant paint whose main component is ammonium polyphosphate that starts foaming at about 200 to 300°C when exposed to heat during a fire, and foams 20 to 30 times to form a heat insulating layer.

[0027] The intermediate coat layer 22 and the top coat layer 24 are thin coating layers formed by an intermediate coat material and a top coat material for fire-resistant paint, respectively. For example, the intermediate coat material can be an epoxy-based resin paint (e.g., FR Top Sealer (manufactured by SK Chemical Co., Ltd.)), and the top coat material can be a urethane-based resin paint (e.g., SK Taicacoat Top Coat Material U (manufactured by SK Chemical Co., Ltd.)).

[0028] The undercoat layer 18, the base coat layer 20, the intermediate coat layer 22, and the top coat layer 24 can all be provided by painting.

[0029] Masking tape 26 is removably applied to a portion of the upper surface of upper flange 14 including planned welding location P. For example, a tape with a base material of Japanese paper, an acrylic adhesive on the front side of the base material, and a synthetic resin mixture on the back side can be used for this masking tape 26. An example of such a tape is the architectural painting masking tape "Kabuki S" (manufactured by Kamoi Kakoshi Co., Ltd.). It is preferable to select a width of masking tape 26 that matches the range of welding of the stud bolt.

[0030] The operation and function of the above configuration will now be described. As shown in Figure 1, the surfaces of the web 12, upper flange 14, and lower flange 16 are polished, degreased, and otherwise prepared. Next, masking tape 26 is applied to the portion of the upper surface of the upper flange 14 that includes the planned welding location P. Thereafter, a primer coat is applied to the entire surfaces of the web 12, upper flange 14, and lower flange 16 to form a primer layer 18. Thereafter, a base coat layer 20, an intermediate coat layer 22, and a top coat layer 24 are formed in predetermined positions to produce the precoated member 10. In this manner, the upper surface of the upper flange 14 is cured before stud welding.

[0031] Next, the precoat member 10 is carried to the construction site of the building and set up at the construction position.

[0032] Just before the stud welding, as shown in Fig. 2, the masking tape 26 is peeled off from the top surface of the upper flange 14 together with the undercoat layer 18. Because the masking tape 26 is integrated with the undercoat layer 18 and has high tensile strength, the masking tape 26 can be easily peeled off from the top surface of the upper flange 14 without interruption. This exposes the base material on the top surface of the upper flange 14. After a ferrule is placed on the exposed planned welding location P, the stud bolt 28 is welded.

[0033] According to this embodiment, when welding the stud bolt 28, no foreign matter that would impede welding is left between the weld end of the stud bolt 28 and the welded surface of the steel beam (the upper surface of the upper flange 14), and contamination of the fire-resistant painted surface of the precoated beam (precoated member 10) by rust fluid can be prevented.

[0034] Therefore, for precoated beams that have been pre-painted with fire-resistant paint in a factory or the like, contamination by rust fluid during the period from outdoor storage to before concrete slab casting can be prevented. In addition, by covering the masking tape 26 with the undercoat layer 18, the masking tape 26 and the undercoat layer 18 are integrated, increasing the tensile strength, so that the masking tape 26 can be easily peeled off from the upper surface of the upper flange 14 without breaking. After the masking tape 26 is peeled off, the base material of the upper surface of the upper flange 14 retains the base material when the undercoat layer 18 was applied, and good stud welding (without foreign matter or floating rust) is possible. In addition, the labor saving of fire-resistant coating work at the site, which is an advantage of precoated beams, can be realized.

[0035] (Verification of the Effects of the Invention) In order to verify the effects of the present invention, the inventors conducted outdoor exposure tests on steel beams that had been coated with fire-resistant paint (undercoat, main coat, intermediate coat, and top coat) and had their upper flanges protected with masking tape.

[0036] Specifically, first, the surface of the steel beam was polished to prepare the base material, and then masking tape was applied to cover the planned welding points on the upper surface of the upper flange. A primer coat was applied on top of this to form a primer layer. Furthermore, each layer was formed by applying a base coat, a middle coat, and a top coat to produce a precoated member according to an embodiment of the present invention. As comparative examples, a steel beam that was not cured with masking tape and a steel beam that did not have the masking tape covered with a primer coat were also prepared.

[0037] The results of the outdoor exposure test showed that rust had developed on the steel beams that had not been protected with masking tape, contaminating the painted surface. Furthermore, the masking tape that was not covered with a primer paint had deteriorated due to exposure and could not be peeled off cleanly. In contrast, the masking tape that was covered with a primer paint could be peeled off easily and cleanly. It is believed that the masking tape that was covered with a primer paint could be peeled off easily and without interruption because the primer paint and the masking tape are integrated and have high tensile strength. After the masking tape covered with a primer paint was peeled off, no rust had developed on the steel base material, and the good base condition it had when it was prepared before painting was maintained. This suggests that normal stud welding can be performed.

[0038] After removing the masking tape, ferrules were placed on the steel frame at the planned welding points, and the stud bolts were welded. As a result, it was confirmed that stud welding could be performed as usual without any problems. Since there was no rust on the top flange, there was no rust contamination on the end and bottom of the top flange or the fireproof coating surface of the web.

[0039] As described above, the precoat member of the present invention is a precoat member comprising a steel member and a fire-resistant paint applied to the surface of the steel member via a primer layer, and further comprising masking tape that is removably applied to the portion of the surface of the steel member that includes the planned welding locations. This makes it possible to prevent contamination of the fire-resistant paint surface by rust fluid and does not leave behind foreign matter that would hinder stud welding.

[0040] In addition, according to another precoat member of the present invention, the undercoat layer is applied to the surface of the steel frame member so as to cover the masking tape applied to the surface of the steel frame member, and the masking tape and the undercoat layer are integrated together, increasing the tensile strength, so that the masking tape can be easily peeled off without cutting.

[0041] According to another precoat member of the present invention, the precoat member has a base coating layer of fire-resistant paint applied on the undercoat layer, an intermediate coating layer applied on the base coating layer, and a top coating layer applied on the intermediate coating layer, and the intermediate coating layer and the top coating layer cover the end of the base coating layer applied on the small end surface of the steel frame member, are cornered along the corner of the small end surface, and are applied on the surface of the steel frame member for a predetermined length from the corner, so that the base coating layer of fire-resistant paint, which is weak against water and may cause swelling when it absorbs water, can be appropriately protected by the intermediate coating layer and the top coating layer. This prevents the components of the fire-resistant paint (e.g., ammonium polyphosphate) from leaching out, and prevents a decrease in fire resistance.

[0042] Furthermore, according to the method for curing a precoated member of the present invention, there is provided a method for curing a precoated member comprising a steel member and a fire-resistant paint applied to the surface of the steel member via a primer layer, in which masking tape is removably attached to the portion of the surface of the steel member including the planned welding locations, and then a primer layer is applied to the surface of the steel member, and the masking tape is peeled off from the surface of the steel member immediately before welding, thereby enabling welding to be performed at the planned welding locations. This prevents contamination of the fire-resistant paint surface by rust fluid and does not leave behind any foreign matter that may hinder stud welding.

[0043] Furthermore, according to another method of curing a precoated member of the present invention, a masking tape is removably applied to a portion of the surface of a steel frame member including the areas to be welded, and then a primer layer is provided on the surface of the steel frame member including the top surface of the masking tape. Immediately before welding, the masking tape is peeled off from the surface of the steel frame member together with the primer layer, thereby enabling welding to be performed at the areas to be welded. Since the masking tape and the primer layer are integrated together to increase the tensile strength, the masking tape can be easily peeled off without cutting. [Industrial Applicability]

[0044] As described above, the precoated member and its curing method according to the present invention are useful for members such as beams and columns, and are particularly suitable for preventing contamination of the fire-resistant paint surface by rust fluid while leaving no foreign matter that would impede stud welding. [Explanation of symbols]

[0045] 10 Precoated material 12. Web 14 Upper flange 16 Bottom flange 18 Undercoat layer 20 Base coating layer (fire-resistant paint) 22 Undercoat layer 24 Topcoat 26 Masking tape 28 Stud bolt P Planned welding location

Claims

1. A precoat member comprising a steel member and a fire-resistant paint applied to a surface of the steel member via an undercoat layer, A precoat member further comprising a masking tape removably applied to a portion of the surface of the steel frame member that includes a location to be welded.

2. 2. The precoat member according to claim 1, wherein the undercoat layer is provided on the surface of the steel frame member so as to cover the masking tape provided on the surface of the steel frame member.

3. 3. A precoat member as described in claim 1 or 2, characterized in that it has a base coating layer of fire-resistant paint applied on an undercoat layer, an intermediate coating layer applied on this base coating layer, and a top coating layer applied on this intermediate coating layer, wherein the intermediate coating layer and the top coating layer cover the ends of the base coating layer applied on the end surface of the steel member and are cornered along the corners of the end surface, and are applied on the surface of the steel member for a predetermined length from the corners.

4. A method for curing a precoat member comprising a steel member and a fire-resistant paint applied to a surface of the steel member via a primer layer, comprising: This method of precoating a steel member is characterized in that a masking tape is removably attached to a portion of the surface of the steel member including a planned welding location, a primer layer is provided on the surface of the steel member, and the masking tape is peeled off from the surface of the steel member immediately before welding, thereby enabling welding to be performed at the planned welding location.

5. A method for curing a precoated member as described in claim 4, characterized in that a masking tape is removably attached to a portion of the surface of a steel member that includes a planned welding location, a primer layer is then provided on the surface of the steel member including the upper surface of the masking tape, and the masking tape is peeled off from the surface of the steel member together with the primer layer immediately before welding, thereby enabling welding to be performed at the planned welding location.

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