Corrosion resistance test method

Abstract

To provide a corrosion resistance testing method capable of appropriately testing the corrosion resistance of a structure. [Solution] The corrosion resistance test method includes a preparation step of preparing a steel structure having welds, a saltwater step of pouring saltwater onto the structure and drying the saltwater, and a confirmation step of checking the occurrence of rust in the areas of the structure where the saltwater was poured, wherein the structure is a building.

Description

[Technical field]

[0001] The present disclosure relates to a corrosion resistance testing method. [Background technology]

[0002] 2. Description of the Related Art As disclosed in Patent Document 1, it has been known to test the corrosion resistance of a lattice formwork for reinforcing a wall surface by a salt spray test, which is one of the corrosion resistance testing methods. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2003-49433 A Summary of the Invention [Problem to be solved by the invention]

[0004] Since bridges, marine structures, and other structures have long service lives, there is a need to test the corrosion resistance of these structures. However, conventional corrosion resistance test methods are not intended for these structures.

[0005] The present disclosure has been made in consideration of the above-mentioned circumstances, and aims to provide a corrosion resistance testing method capable of appropriately testing the corrosion resistance of a structure. [Means for solving the problem]

[0006] A corrosion resistance testing method according to one aspect of the present disclosure includes a preparation step of preparing a steel structure having a welded joint, a saltwater step of pouring saltwater onto the structure and drying the saltwater, and a confirmation step of checking the occurrence of rust in the portions of the structure where the saltwater has been poured, wherein the structure is a building. Effect of the Invention

[0007] According to one aspect of the present disclosure, it is possible to provide a corrosion resistance testing method capable of appropriately testing the corrosion resistance of a structure. [Brief description of the drawings]

[0008] [Figure 1] 1 is a cross-sectional view of a bridge as an example of a structure to be tested in a corrosion resistance testing method according to a first embodiment. FIG. [Diagram 2] 1 is a flowchart of a corrosion resistance test method according to a first embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] First Embodiment Hereinafter, a corrosion resistance testing method according to a first embodiment of the present disclosure will be described with reference to the drawings. In this embodiment, the structure to be tested by the corrosion resistance test method is a building such as a bridge or a marine structure. The building is made of steel including at least one of stainless steel and clad steel. Below, as an example, a corrosion resistance test method for a bridge will be described. Note that the standard design service life of a bridge is long, about 50 years (about 100 years in some cases), so there is a demand to test the corrosion resistance of the bridge.

[0010] FIG. 1 is a cross-sectional view of a bridge 1. The bridge 1 comprises a deck 10, and main girders 15 and cross girders 16 that support the deck 10. The main girders 15 extend in the length direction of the bridge 1 (the bridge axis direction; the same applies below). A pair of main girders 15 are provided at intervals in the width direction of the bridge 1 (the direction perpendicular to the bridge axis; the same applies below). The cross girders 16 extend in the width direction of the bridge 1. Multiple cross girders 16 are provided at intervals in the length direction of the bridge 1.

[0011] The deck 10 is a steel deck. The deck 10 has a deck plate 11, vertical ribs 12, and horizontal ribs 13.

[0012] The deck plate 11 is a flat plate made of steel plate. The deck plate 11 is formed by welding a plurality of flat plates together (for example, butt welding, lap welding, etc.). A paving portion (not shown) is constructed on the upper surface of the deck plate 11. A main girder 15 and a cross girder 16 are welded to the lower surface of the deck plate 11.

[0013] The longitudinal ribs 12 are used to reinforce the deck plate 11. The longitudinal ribs 12 extend in the longitudinal direction of the bridge 1. A plurality of the longitudinal ribs 12 are provided at intervals in the width direction of the bridge 1. The longitudinal ribs 12 have a substantially U-shaped cross section. The longitudinal ribs 12 are joined to the underside of the deck plate 11 by welding.

[0014] The transverse ribs 13 are disposed at right angles to the longitudinal ribs 12. The transverse ribs 13 support the longitudinal ribs 12 on the lower surface side of the deck plate 11. The transverse ribs 13 are joined to the main girders 15 by welding.

[0015] As described above, each component of the bridge 1 is joined together by welding. That is, the bridge 1 has a plurality of welds W. In this embodiment, the welds W include joints made by welding, parts affected by the heat of welding, and parts where spatter has scattered. The welds W include a weld W1 between the lower surface of the deck plate 11 and the vertical rib 12, a weld W2 between the lower surface of the deck plate 11 and the main girder 15, and a weld W3 between the main girder 15 and the horizontal rib 13. The welds W also include welds between a plurality of flat plates in the deck plate 11. Furthermore, when the main girder 15 and the cross girder 16 are formed by welding a plurality of flat plates together (for example, butt welding, lap welding, etc.), the welds W include welds between a plurality of flat plates in the main girder 15 and the cross girder 16.

[0016] The bridge 1 includes a general portion 21 and a complex portion 22 having a more complex shape than the general portion 21. The general portion 21 is a flat portion of the bridge 1. For example, the general portion 21 includes flat plate portions of the cross rib 13, the main girder 15, and the cross girder 16. The complex portion 22 includes a plurality of welds W (i.e., welds W1 to W3, welds between flat plates, etc.). In addition, a vertical rib 12 is provided on the upper surface of the deck 10, thereby forming a narrow portion 23 having a narrower shape than the general portion 21. The complex portion 22 includes the narrow portion 23.

[0017] The corrosion resistance test method will be described with reference to Fig. 2. The corrosion resistance test method of this embodiment includes a preparation step S1, a salt water step S2, a confirmation step S3, a salt removal step S4, and a repair step S5.

[0018] In a preparation step S1, a bridge 1 having a welded portion W is prepared.

[0019] In the salt water step S2, salt water is poured onto the bridge 1 and then dried. In the salt water step S2, the process of pouring salt water onto the bridge 1 and then drying the salt water is repeated multiple times. In the salt water step S2, for example, salt water is poured onto the bridge 1 by spraying it onto the bridge 1. Note that salt water may also be sprinkled onto the bridge 1. Hereinafter, the areas of the bridge 1 where salt water has been poured are referred to as salt water areas.

[0020] In the salt water step S2, salt water is poured onto the welded portion W of the bridge 1. That is, the salt water areas include the welded portion W of the bridge 1. Also, in the salt water step S2, salt water is poured onto both the general portion 21 and the complex portion 22 of the bridge 1. That is, the salt water areas include the general portion 21 and the complex portion 22 of the bridge 1. In this embodiment, the general portion 21 and the complex portion 22 are poured with salt water and dried the same number of times.

[0021] In the confirmation step S3, the occurrence of rust in the saltwater area is confirmed. Specifically, in the confirmation step S3, the degree of rust in the saltwater area is judged based on criteria related to at least one of the presence or absence of rust, the size of the rust, and the type of rust. The presence or absence of rust is confirmed, for example, by visual inspection. For example, if the size (diameter) of the rust is greater than 1 mm, it may be judged that rust is present, and if the size (diameter) of the rust is 1 mm or less, it may be judged that rust is not present. Types of rust include, for example, red rust, stained rust, etc.

[0022] Among the saltwater areas, portions where rust has been confirmed (i.e., portions determined in confirmation step S3 to not satisfy the criteria, hereinafter referred to as rust-occurring portions) are subjected to salt removal step S4 and repair step S5. That is, if rust has been confirmed in confirmation step S3 (step S3: YES), the process proceeds to salt removal step S4. On the other hand, if rust has not been confirmed in confirmation step S3 (step S3: NO), the process ends.

[0023] In the salt removal step S4, salt is removed from the rusted parts, for example by pouring water onto the rusted parts. In the repair step S5, the rust-occurring portion from which the salt was removed in the salt removal step S4 is repaired. After that, the process returns to the salt water step S2, and the salt water step S2 and the confirmation step S3 are performed again on the rust-occurring portion. If the occurrence of rust is not confirmed in the confirmation step S3 (step S3: NO), the process ends.

[0024] As described above, the corrosion resistance test method according to this embodiment includes a preparation step S1 for preparing a steel structure (bridge 1) having a welded part W, a saltwater step S2 for pouring saltwater on the structure and drying the saltwater, and a confirmation step S3 for confirming the occurrence of rust in the saltwater parts of the structure where the saltwater was poured. The structure is a building. According to the above configuration, the corrosion resistance of a structure can be appropriately tested.

[0025] The structure also has a general portion 21 and a complex portion 22 having a more complex shape than the general portion 21. The saltwater location includes the general portion 21 and the complex portion 22. According to the above configuration, in a building, it is possible to appropriately test the corrosion resistance of not only the general portion 21 but also the complex portion 22 having a complex shape.

[0026] Additionally, the complex portion 22 has a narrow portion 23 that is narrower than the general portion 21 . According to the above-mentioned configuration, it is possible to appropriately test the corrosion resistance of the narrow portion 23 having a complicated shape.

[0027] The saltwater area also includes a welded portion W. According to the above configuration, it is possible to appropriately test the corrosion resistance of parts of a structure where rust is likely to occur (for example, joints made by welding, parts affected by the heat of welding, parts where spatter is scattered, etc.).

[0028] In addition, in the salt water step S2, the general portion 21 and the complex portion 22 are sprayed with salt water and dried the same number of times. According to the above configuration, the number of times salt water is sprayed in the salt water step S2 can be easily managed.

[0029] In addition, in the salt water step S2, the process of pouring salt water on the structure and drying it is carried out multiple times. According to the above configuration, by repeatedly pouring salt water on a structure (building) and drying it, the salt in the salt water area is concentrated, making it possible to check the state of rust formation under a more severe environment.

[0030] In addition, in the saltwater step S2, saltwater is sprayed onto the structure. According to the above-mentioned configuration, the salt water particles on the structure (building) become finer, so that the salt water can be easily dried.

[0031] In addition, in confirmation step S3, the degree of rust at the saltwater portion is determined based on criteria related to at least one of the presence or absence of rust, the size of the rust, and the type of rust. According to the above configuration, the occurrence state of rust can be confirmed more accurately based on the above criteria.

[0032] The corrosion resistance test method also includes a repair step S5 for repairing rust-caused portions of the saltwater locations that are determined not to satisfy the criteria in the confirmation step S3. According to the above configuration, it is possible to carry out repairs on rust-occurring portions that are determined not to satisfy the criteria in the confirmation step S3.

[0033] The corrosion resistance test method also includes a salt removal step S4 for removing salt from the rusted portion before the repair step S5 is performed. According to the above configuration, by removing salt from the rust-occurring portion before carrying out repair, it is possible to suppress the occurrence of rust after repair.

[0034] The structure is also made of steel including at least one of stainless steel and clad steel. According to the above-mentioned configuration, it is possible to appropriately test the corrosion resistance of a steel structure containing at least one of stainless steel and clad steel. Furthermore, since the structure is made of steel containing at least one of stainless steel and clad steel, it has sufficient corrosion resistance and can reduce costs compared to the case of using titanium, for example.

[0035] The structure is also a bridge. According to the above configuration, it is possible to appropriately test the corrosion resistance of the bridge 1, which has a long service life and therefore requires checking the occurrence of rust.

[0036] The complex portion 22 also includes the upper surface portion of the deck 10 of the bridge 1 . According to the above-described configuration, the corrosion resistance of the upper surface of the deck 10 having a complex shape can be appropriately tested.

[0037] Second embodiment Next, a corrosion resistance test method according to a second embodiment of the present disclosure will be described. In this embodiment, in the salt water step S2, the complex portion 22 is sprayed with salt water and dried more times than the general portion 21. According to the above configuration, by repeatedly pouring salt water on the complex part 22 having a complex shape and drying it, the salt in the salt water area is concentrated, making it possible to check the occurrence of rust under a more severe environment.

[0038] The present disclosure is not limited to the above-described embodiment described with reference to the drawings, and various modifications are possible within the technical scope of the present disclosure.

[0039] In the above embodiment, a bridge 1 is exemplified as a structure (building) to be tested by the corrosion resistance test method. However, the structure to be tested by the corrosion resistance test method may be any building, and is not limited to a bridge. For example, the structure to be tested by the corrosion resistance test method may be an offshore structure. The offshore structure is, for example, a fixed-bottom structure or a floating structure. Fixed-bottom structures include jacket foundations and monopile foundations. Floating structures include floating foundations and ships.

[0040] In the above embodiment, it has been described that in the confirmation step S3, if the size of the rust is larger than 1 mm, it is determined that there is rust, and if the size of the rust is 1 mm or less, it is determined that there is no rust. However, the present disclosure is not limited to this. For example, even if there is spot rust with a diameter of 1 mm or less, if the type of rust is red rust, it may be determined that there is rust. Even if there is spot rust with a diameter of 1 mm or less, if the type of rust is stain rust, it may be determined that there is rust.

[0041] In addition, within the scope of the present disclosure, the components in the above-described embodiments may be replaced with well-known components as appropriate, and the above-described modified examples may be combined as appropriate.

[0042] (Additional Note) The corrosion resistance test method according to the embodiment can be understood, for example, as follows. <1> A corrosion resistance testing method according to one aspect of the present disclosure includes a preparation step of preparing a steel structure having a welded joint, a saltwater step of pouring saltwater onto the structure and drying the saltwater, and a confirmation step of checking the occurrence of rust in the portions of the structure where the saltwater has been poured, wherein the structure is a building. According to the above configuration, the corrosion resistance of a structure can be appropriately tested.

[0043] <2> the above <1> In the corrosion resistance test method according to the present invention, the structure has a general part and a complex part having a shape more complex than that of the general part, and the location may include both the general part and the complex part. According to the above configuration, it is possible to appropriately test the corrosion resistance of not only general parts of a building but also complex parts with complex shapes.

[0044] <3> the above <2> In the corrosion resistance test method according to the present invention, the complex portion may have a narrow portion having a shape narrower than that of the general portion. According to the above configuration, it is possible to appropriately test the corrosion resistance of narrow parts having complicated shapes.

[0045] <4> the above <1> from <3> In the corrosion resistance test method according to any one of the above, the location may include the welded portion. According to the above configuration, it is possible to appropriately test the corrosion resistance of parts of a structure where rust is likely to occur (for example, joints made by welding, parts affected by the heat of welding, parts where spatter is scattered, etc.).

[0046] <5> the above <2> or <3> In the corrosion resistance test method according to the present invention, in the saltwater step, the general portion and the complex portion may be sprayed with saltwater and dried the same number of times. According to the above configuration, the number of times salt water is sprayed in the salt water step can be easily managed.

[0047] <6> the above <2> or <3> In the corrosion resistance test method according to the present invention, in the saltwater step, the complex portion may be sprayed with saltwater and dried more times than the general portion. According to the above configuration, by repeatedly pouring salt water on complex parts having complex shapes and then drying them, the salt in the above areas is concentrated, making it possible to check the occurrence of rust in more severe environments.

[0048] <7> the above <1> from <6> In the corrosion resistance testing method according to any one of the above, in the salt water step, a process of pouring salt water on the structure and drying it may be performed multiple times. According to the above configuration, by repeatedly pouring salt water on a structure (building) and drying it, the salt in the above-mentioned area is concentrated, making it possible to check the state of rust formation under a more severe environment.

[0049] <8> the above <1> from <7> In the corrosion resistance testing method according to any one of the above, in the salt water step, salt water may be sprayed onto the structure. According to the above-mentioned configuration, the salt water particles on the structure (building) become finer, so that the salt water can be easily dried.

[0050] <9> the above <1> from <8> In the corrosion resistance testing method according to any one of the above, in the confirmation step, the degree of rust at the location may be determined based on criteria related to at least one of the presence or absence of rust, the size of the rust, and the type of rust. According to the above configuration, the occurrence state of rust can be confirmed more accurately based on the above criteria.

[0051] <10> the above <9> The corrosion resistance testing method according to the present invention may further include a repair step of repairing any portion of the location that is determined not to satisfy the criteria by the checking step. According to the above configuration, it is possible to carry out repairs on the portion that is determined not to satisfy the criteria in the confirmation step.

[0052] <11> the above <10> The corrosion resistance test method according to the above aspect may further include a salt removal step of removing salt from the portion before the repair step is performed. According to the above configuration, by removing salt from the above portion before carrying out repair, it is possible to suppress the occurrence of rust after repair.

[0053] <12> the above <1> from <11> In the corrosion resistance testing method according to any one of the above, the structure may be made of steel including at least one of stainless steel and clad steel. According to the above-mentioned configuration, it is possible to appropriately test the corrosion resistance of a steel structure containing at least one of stainless steel and clad steel. Furthermore, since the structure is made of steel containing at least one of stainless steel and clad steel, it has sufficient corrosion resistance and can reduce costs compared to the case of using titanium, for example.

[0054] <13> the above <1> from <12> In the corrosion resistance testing method according to any one of the above, the structure may be a bridge. According to the above configuration, it is possible to appropriately test the corrosion resistance of bridges, which have a long service life and therefore require checking the occurrence of rust.

[0055] <14> the above <2> or <3> In the corrosion resistance test method according to the above, the complex portion may include an upper surface portion of a bridge deck. According to the above configuration, the corrosion resistance of the upper surface of a deck having a complex shape can be appropriately tested.

[0056] <15> the above <1> from <12> In the corrosion resistance testing method according to any one of the above, the structure may be a marine structure. <16> the above <15> In the corrosion resistance test method according to the present invention, the marine structure may be a bottom-fixed structure or a floating structure. According to the above configuration, it is possible to appropriately test the corrosion resistance of marine structures which have a long service life and therefore require checking the occurrence of rust. [Explanation of symbols]

[0057] 1 Bridge (structure, building) 10 Floor slab 21 General section 22 Complex Part 23 Narrow area S1 Preparation Steps S2 Salt Water Step S3 Verification Step S4 Salt removal step S5 Repair Steps

Claims

1. A preparation step of preparing a steel structure having a weld; A salt water step of spraying salt water on the structure and drying the salt water; and a confirmation step of confirming the occurrence of rust at the portion of the structure where the salt water has been sprayed, The structure is a building, In the confirmation step, the degree of rust in the portion is judged based on criteria related to at least one of the presence or absence of rust, the size of the rust, and the type of rust; A corrosion resistance testing method comprising a repair step of repairing any portion of the location that is determined not to satisfy the criteria by the confirmation step.

2. The building has a general part and a complex part having a more complex shape than the general part, The corrosion resistance test method according to claim 1 , wherein the locations include the general portion and the complex portion.

3. The corrosion resistance testing method according to claim 2 , wherein the complex portion has a narrow portion having a narrower shape than the general portion.

4. The corrosion resistance test method according to claim 1 , wherein the location includes the welded portion.

5. 4. The corrosion resistance testing method according to claim 2 or 3, wherein in the salt water step, the general portion and the complex portion are sprayed with salt water and dried the same number of times.

6. 4. The corrosion resistance testing method according to claim 2 or 3, wherein in the salt water step, the complex portion is sprayed with salt water and dried more times than the general portion.

7. 4. The corrosion resistance testing method according to claim 1, wherein in the salt water step, the step of pouring salt water on the structure and drying it is performed a plurality of times.

8. The corrosion resistance testing method according to claim 1 , wherein in the salt water step, salt water is sprayed onto the structure.

9. The corrosion resistance testing method according to any one of claims 1 to 3, further comprising a salt removal step of removing salt from the portion before the repair step is performed.

10. The corrosion resistance testing method according to any one of claims 1 to 3, wherein the structure is made of steel including at least one of stainless steel and clad steel.

11. The corrosion resistance testing method according to any one of claims 1 to 3, wherein the structure is a bridge.

12. The corrosion resistance testing method according to claim 2 or 3, wherein the complex portion includes an upper surface portion of a bridge deck.

13. The corrosion resistance testing method according to any one of claims 1 to 3, wherein the structure is a marine structure.

14. The corrosion resistance test method according to claim 13, wherein the marine structure is a bottom-fixed structure or a floating structure.

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