Steel structure and overlay welding method

Abstract

An object of the present disclosure is to provide a steel structure and an overlay welding method capable of improving corrosion resistance of an edge surface of clad steel.SOLUTION: A steel structure 1 includes clad steels 10 including mating materials 12 and base materials 11, corrosion-resistant metals 20 are build-up welded to the 10c parts of the edge surfaces of the clad steels 10, and chamfered parts 13 are formed in parts of the 10c parts of the edge surfaces at corner parts on the side of the 10c parts of the edge surfaces and on the side opposite to the mating materials 12.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a steel structure and an overlay welding method. [Background technology]

[0002] 2. Description of the Related Art Overlay welding has conventionally been performed on chamfered portions of structures. Patent Document 1 discloses forming a chamfer on the lower edge of the outer circumferential surface of the lower end steel pipe of an offshore structure and overlay welding the lower surface of the lower end steel pipe. Patent Document 2 discloses overlay welding the end surface of a clad pipe that has been chamfered into a tapered shape during butt welding. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-79742 [Patent Document 2] Japanese Patent Application Publication No. 7-24577 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in Patent Documents 1 and 2, there was room for improvement in terms of corrosion resistance in overlay welding on the edge surface of a steel pipe. Also, from the viewpoint of improving corrosion resistance, the present inventors considered adopting clad steel instead of steel members.

[0005] An object of the present invention is to provide a steel structure and an overlay welding method that can improve the corrosion resistance of the edge surface of clad steel. [Means for solving the problem]

[0006] The structure according to the present disclosure comprises: A clad steel including a composite material and a base material, A corrosion-resistant metal is overlaid and welded onto the edge surface of the clad steel, A chamfer is formed on a corner of the edge surface, the corner being on the side opposite to the cladding material. It is characterized by: [Effects of the Invention]

[0007] According to the present disclosure, it is possible to provide a steel structure and an overlay welding method that can improve the corrosion resistance of the edge surface of clad steel. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a schematic diagram for explaining a steel structure according to an embodiment of the present disclosure, and is a cross-sectional view of the vicinity of the edge surface of clad steel. [Figure 2] 1 is a schematic diagram illustrating a structure according to an embodiment of the present disclosure, showing a cross-sectional view of clad steel. [Figure 3] FIG. 1 is a schematic diagram for explaining an overlay welding method according to an embodiment of the present disclosure, and is a cross-sectional view of clad steel. [Figure 4] FIG. 1 is a schematic diagram for explaining an overlay welding method according to an embodiment of the present disclosure, and is a cross-sectional view showing a state in which a chamfered portion is provided on clad steel. [Figure 5] FIG. 1 is a schematic diagram for explaining an overlay welding method according to one embodiment of the present disclosure, and is a cross-sectional view showing a state in which a corrosion-resistant metal has been formed on the edge surface of clad steel having a chamfered portion. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present disclosure will be described using examples, but it is clear that the present disclosure is not limited to the examples described below. In the following description, specific numerical values ​​and materials may be used as examples, but other numerical values ​​and materials may be used as long as the effects of the invention according to the present disclosure are obtained. Furthermore, the components of the following embodiments can be combined with each other. Furthermore, in this specification, a numerical range expressed using "to" means a range that includes the numerical values ​​before and after "to" as the lower and upper limits. In this specification, the term "step" includes not only an independent process, but also a process that cannot be clearly distinguished from other processes, as long as the intended purpose of the process is achieved.

[0010] [First embodiment] Hereinafter, a steel structure according to an embodiment of the present disclosure will be described with reference to the drawings. Fig. 1 shows a schematic cross-sectional view illustrating a steel structure according to an embodiment of the present disclosure. Fig. 1 shows a cross section perpendicular to the direction in which an edge surface 10c of clad steel 10 extends. Fig. 1 shows a portion of clad steel 10 near edge surface 10c of clad steel 10. Note that in this embodiment, the clad steel 10 is described as a clad steel plate.

[0011] A steel structure 1 according to this embodiment includes a clad steel 10 including a clad material 12 and a base material 11. In this steel structure 1, a corrosion-resistant metal 20 is overlaid and welded onto an edge surface 10c of the clad steel 10. In addition, in this steel structure 1, a chamfered portion 13 is formed on a corner of the edge surface 10c, which is on the side opposite the clad material 12.

[0012] According to the steel structure 1 having the above-described configuration, the corrosion resistance of the edge surface 10c of the clad steel 10 can be improved. When overlay welding is performed on the edge surface of clad steel, the chemical components of the base material are likely to mix with the corrosion-resistant metal 20, which is the weld metal that makes up the overlay weld, particularly in the corrosion-resistant metal (overlay weld) 20 at the corners located on the side where no clad material is provided. However, in the steel structure 1 according to this embodiment, because these corners are chamfered, even if the chemical components of the base material 11 mix with the weld metal, this can be suitably prevented from affecting the corrosion resistance of the surface of the corrosion-resistant metal 20.

[0013] (Clad steel) The clad steel 10 includes a steel base material 11 and a cladding material 12 that coats the base material 11 . The clad steel 10 has a surface 10a on the side where the clad material 12 is provided and a surface 10b on the side where the clad material 12 is not provided. The surface 10a and the surface 10b are aligned in the thickness direction of the base material 11 and the clad material 12.

[0014] The clad steel 10 has a corner 10d where the surface 10a on the side where the clad material 12 is located is connected to the edge surface 10c. Moreover, the clad steel 10 before chamfering, as exemplified in Fig. 3, has a corner 10e where the surface 10b opposite the surface 10a of the clad steel 10 is connected to the edge surface 10c. In other words, the clad steel 10 has corners 10d and 10e on either side of the edge surface 10c.

[0015] In Figure 1 etc., edge surface 10c extends along the X coordinate axis. Corner 10d and corner 10e also extend along the X coordinate axis. In the example of Figure 1, the thickness direction of clad steel 10 intersects with the X coordinate axis and the Y coordinate axis.

[0016] The edge surface 10c of the clad steel 10 means the surface of the edge of the clad steel 10. The edge surface 10c of the clad steel 10 is inclined with respect to the surface 10a or surface 10b of the clad steel 10. Alternatively, the edge surface 10c and the surface 10a or surface 10b of the clad steel 10 are approximately perpendicular. The X coordinate axis, Y coordinate axis, and Z coordinate axis in FIGS. 1 to 6 are perpendicular to each other.

[0017] The base material 11 is a steel plate. The steel plate of the base material 11 is not particularly limited, but is more preferably a steel plate containing, as a chemical composition, P: 0.05% or less and S: 0.05% or less. The chemical composition of the base material 11 may be determined by referring to a mill sheet that lists the steel type and chemical components. However, instead of using such a method, the steel plate to be used may be specified by a trade name or the like, and it may be determined whether the base material 11 is a steel plate based on the specifications of the steel plate.

[0018] The cladding material 12 is provided on one surface of the base material 11. It is preferable that the cladding material 12 is provided on the entire surface of the base material 11. The material constituting the laminate 12 is not particularly limited, but examples thereof include stainless steel, titanium, and nickel-based alloys.

[0019] The cladding material 12 is preferably made of stainless steel or a nickel-based alloy because it is easy to process, such as by welding. The cladding material 12 is more preferably made of, for example, SUS312L, SUS430, etc. From the viewpoint of corrosion resistance, SUS312L is more preferable.

[0020] The thickness of the clad steel 10 is not particularly limited, but is preferably 7 mm or more from the viewpoint of strength. The thickness of the base material 11 constituting the clad steel 10 is not particularly limited, but is preferably 6 mm or more from the viewpoint of strength. The thickness of the laminated material 12 constituting the clad steel 10 is not particularly limited, but is preferably 1 mm or more from the viewpoint of ensuring corrosion resistance. These thicknesses are measured using a vernier caliper.

[0021] The clad steel 10 as described above is manufactured by joining a steel plate that will be the base material 11 and a material that will be the clad material 12 by pressure welding, explosive welding, melt welding, rolling, overlay welding, welding, or the like. Therefore, for example, the clad steel 10 used in the steel structure 1 according to this embodiment is different from a member in which a steel plate and a metal plate of another type are welded on-site.

[0022] Note that interface 10f between base material 11 and laminated material 12 may be inclined with respect to surface 10a or surface 10b depending on manufacturing conditions, etc. Interface 10f may also be an interface layer having a certain thickness.

[0023] (corrosion-resistant metal) In the steel structure 1 according to this embodiment, a corrosion-resistant metal is overlaid on the edge surface 10c of the clad steel 10 by welding. In the example of FIG. 1, the corrosion-resistant metal 20 extends in a direction along the X coordinate axis.

[0024] The corrosion-resistant metal is, for example, a nickel-based alloy, etc. The corrosion-resistant metal 20 is not particularly limited, but examples thereof include Hastelloy (registered trademark) and Inconel (registered trademark). From the viewpoint of reliably protecting the base material 11, the thickness of the corrosion-resistant metal 20 in the direction perpendicular to the extending direction of the edge surface 10c of the clad steel 10 and the plate thickness direction of the base material 11 is preferably 3 mm or more.

[0025] By providing the corrosion-resistant metal 20 made of such a corrosion-resistant metal, the edge surface 10c of the clad steel 10 is not exposed to a corrosive environment, and the edge surface 10c of the clad steel 10 becomes less susceptible to corrosion.

[0026] In the steel structure 1 according to this embodiment, it is more preferable that the edge surface 10c includes the edge surface 12c of the cladding material 12 and the edge surface 11c of the base material 11. In other words, it is more preferable that the corrosion-resistant metal 20 is provided over both the edge surface of the cladding material 12 and the edge surface of the base material. This makes it possible to more reliably ensure the corrosion resistance of the edge surface of the clad steel.

[0027] In the steel structure 1 of this embodiment, the edge surface 12c of the clad steel 12 and the edge surface 11c of the base material 11 may be in the same position in the direction perpendicular to the extension direction of the edge surface 10c of the clad steel 10 and the thickness direction of the base material 11. This allows the amount of corrosion-resistant metal 20 to be overlaid and welded to be reduced.

[0028] (chamfered part) In the steel structure 1 according to this embodiment, a chamfered portion 13 is formed on a corner of the edge surface 10c, which is on the side opposite to the clad material 12, on the edge surface 10c. The surface of the chamfered portion 13 is inclined with respect to the surface of the edge surface 10c. The chamfered portion 13 is connected to the surface 10b at the end 13a. The chamfered portion 13 is connected to the edge surface 10c at the end 13b. The chamfered portion 13 is provided along the extension direction of the edge surface 10c. It is more preferable that the chamfered portion 13 is provided over the entire length of the edge surface 10c in the extension direction.

[0029] A corrosion-resistant metal 20 is provided on the chamfered portion 13. The chamfered portion 13 is formed so as to be recessed more inward into the base material 11 than the edge surface 10c and the surface 10b. Therefore, as shown in FIG. 1 etc., in the direction perpendicular to the extending direction of the edge surface 10c and the thickness direction of the base material 11, the thickness of the corrosion-resistant metal 20 provided on the chamfered portion 13 is thicker than the thickness of the corrosion-resistant metal 20 on the edge surface 10c.

[0030] In the steel structure 1 according to this embodiment, such a chamfered portion 13 is provided on the side where the cladding material 12 is not provided, so that the distance from the base material 11 to the corrosion-resistant metal end portion 20s is long in the corrosion-resistant metal 20 near the chamfered portion 13. Therefore, even if the chemical components of the base material 11 are mixed with the weld metal constituting the corrosion-resistant metal 20, it is possible to suitably prevent the corrosion resistance of the surface of the corrosion-resistant metal 20 from being affected.

[0031] The shape of chamfered portion 13 is not limited to the flat surface shown in Fig. 1 etc. It is sufficient that chamfered portion 13 ensures the distance from the end of corrosion-resistant metal 20 to base material 11 at the corner opposite to laminated material 12. For example, chamfered portion 13 may be formed in a stepped shape from end 13a to edge surface 10c, or may have a rounded recess shape when viewed along the extending direction of edge surface 10c.

[0032] (Stainless steel plate lining) In the steel structure 1 according to this embodiment, it is more preferable that the base material 11 is provided with a stainless steel plate lining 30. The stainless steel plate lining 30 is provided on the base material 11 side of the clad steel 10, i.e., on the surface 10b side on which the clad material 12 is not provided.

[0033] Furthermore, with regard to the lining 30 of the stainless steel plate, in a direction perpendicular to the extending direction of the edge surface 10c and the plate thickness direction of the base material 11, it is more preferable that the distance d1 from the corrosion-resistant metal end 20s, which is the end of the corrosion-resistant metal 20 opposite the edge surface 10c, to the end 30a of the lining 30 of the stainless steel plate on the edge surface 10c side, is shorter than the distance d2 from the corrosion-resistant metal end 20s to the end 13a of the chamfered portion 13 opposite the edge surface 10c.

[0034] This allows the surface 10b of the clad steel 10 to be protected, while reducing the amount of stainless steel plate used for the lining 30 compared to when the lining 30 is provided up to the corrosion-resistant metal end 20s. At the end 13b of the chamfered portion 13 on the edge surface 10c side, the thickness of the corresponding corrosion-resistant metal 20 is sufficient in the thickness direction of the clad steel 10, so that the components of the base material 11 are less likely to mix with the corrosion-resistant metal and affect the surface. Therefore, the stainless steel plate lining 30 can be omitted.

[0035] The corrosion-resistant metal end 20s is, in other words, the surface of the corrosion-resistant metal 20. The corrosion-resistant metal end 20s is a surface located on the opposite side of the corrosion-resistant metal 20 from the edge surface 10c of the clad steel 10. The end 30a of the lining 30 of the stainless steel plate on the edge surface 10c side means the end on the side where the chamfered portion 13 is formed. In other words, the end 30a is the end closer to the edge surface 10c on which the corrosion-resistant metal 20 is provided, among the ends in the direction perpendicular to the extending direction of the edge surface 10c and the plate thickness direction of the base material 11. Among the ends in the direction perpendicular to the extending direction of the edge surface 10c and the thickness direction of the base material 11, the end located opposite to the end 30a is referred to as end 30b. In other words, end 30b is the end farther from the edge surface 10c on which the corrosion-resistant metal 20 is provided.

[0036] Among the ends of the chamfered portion 13, the end 13a opposite the edge surface 10c is the end farthest from the corrosion-resistant metal end 20s. For example, in the example of Fig. 1, among the ends of the chamfered portion 13, the end 13a opposite the edge surface 10c is the end 13a farthest from the corrosion-resistant metal end 20s.

[0037] In the steel structure 1 according to this embodiment, in the chamfered portion 13, the corrosion-resistant metal 20 may be sandwiched between the stainless steel plate lining 30 and the chamfered portion 13 when viewed along the direction in which the clad material 12 and the base material 11 are aligned. This makes it possible to more reliably prevent the components of the base material 11 from being mixed into the corrosion-resistant metal 20 .

[0038] A schematic cross-sectional view for explaining a steel structure according to an embodiment of the present disclosure is shown in Fig. 2. Fig. 2 shows a cross section perpendicular to the direction in which an edge surface 10c of clad steel 10 extends.

[0039] The end 10g is an edge surface located on the opposite side to the edge surface 10c across the clad steel 10. In the clad steel 10 according to this embodiment, no corrosion-resistant metal is provided on the end 10g side.

[0040] The thickness of the stainless steel lining 30 may be thinner than the thickness of the cladding material 12. This has the advantage of improving economy.

[0041] The stainless steel plate lining 30 is joined to the base material 11 of the clad steel 10 by welding.

[0042] (Variation)

[0043] In the steel structure 1 according to the above embodiment, the chamfered portion 13 and the corrosion-resistant metal 20 may be provided on all edge surfaces of the clad steel 10. Alternatively, the chamfered portion 13 and the corrosion-resistant metal 20 may be provided on only a portion of the edge surfaces of the clad steel 10. For example, when the clad steel plate is rectangular, the chamfered portion 13 and the corrosion-resistant metal 20 may be provided on all sides of the steel plate, or the chamfered portion 13 and the corrosion-resistant metal 20 may be provided on only some of the sides. Also, the chamfered portion 13 and the corrosion-resistant metal 20 may be provided on only some of the sides.

[0044] In the steel structure 1 according to the above embodiment, the steel structure 1 may be a steel plate, the cladding material 12 may be provided on one surface of the steel plate, and the chamfered portion 13 may be formed on the other surface of the steel plate. That is, the cladding material 12 may be a surface of the steel plate that forms the front side, and the chamfered portion 13 may be formed on the surface of the steel plate opposite to the front side. This configuration is preferable when the front side is in a more corrosive environment than the opposite side.

[0045] In the steel structure 1 according to the above embodiment, the steel structure 1 may be a steel pipe, the cladding material 12 may form the outer surface of the steel pipe, and the chamfered portion 13 may be formed on the inner surface of the steel pipe. According to the steel structure 1 having the above-mentioned configuration, it is possible to prevent components of the base material 11 from mixing with the corrosion-resistant metal 20 from the edge surface portion on the inner surface side of the steel pipe and affecting the surface of the corrosion-resistant metal 20.

[0046] In the above embodiment, the clad steel 10 is in the form of a plate, i.e., a steel structure including a clad steel plate is described as an example, but the clad steel 10 is not limited to this. For example, the clad steel 10 may be a pipe made by bending a clad steel plate. When the clad steel is a pipe, the edge surface of one end in the axial direction of the pipe may be provided with the chamfered portion 13 and the corrosion-resistant metal 20 as described above. Note that the chamfered portion 13 and the corrosion-resistant metal 20 may be provided only on a part of the entire circumference of the edge surface of one end of the pipe. Alternatively, the chamfered portion 13 and the corrosion-resistant metal 20 as described above may be provided on the edge surfaces of both ends in the axial direction of the pipe.

[0047] [Second embodiment] Hereinafter, an overlay welding method according to an embodiment of the present disclosure will be described. The overlay welding method according to this embodiment is a method for overlay welding a clad steel including a clad material and a base material, and includes a forming step, a welding step, and a lining step.

[0048] (Formation step) In the forming step (S1), a chamfered portion 13 is formed on a part of the edge surface 10c of the clad steel 10. In the forming step, a clad steel as shown in Fig. 3 is prepared, and a chamfered portion 13 is formed to obtain the state shown in Fig. 4. The chamfered portion 13 is formed at a corner 10e on the edge surface 10c side of the base material 11, which is opposite to the clad material 12.

[0049] (welding step) In the welding step (S2), the corrosion-resistant metal 20 is overlaid on the edge surface 10c by welding. In the welding step, a corrosion-resistant metal 20 is formed by build-up welding on the edge surface 10c of the clad steel 10 provided with the chamfered portion 13, resulting in a state as shown in FIG.

[0050] In the welding step, it is preferable to perform overlay welding in multiple passes. After overlay welding the corrosion-resistant metal 20, the surface may be ground to form the corrosion-resistant metal end 20s. Alternatively, the surface of the corrosion-resistant metal 20 formed by overlay welding may serve as the corrosion-resistant metal end 20s.

[0051] (Lining step) In the lining step (S3), a lining 30 made of a stainless steel plate is provided on the base material 11 side. In the lining step, a lining 30 of stainless steel plate is formed so as to cover the surface 10b of the clad steel 10 on the base material 11 side and part of the corrosion-resistant metal 20 when viewed in the plate thickness direction of the clad steel 10.

[0052] In the overlay welding method according to this embodiment, it is more preferable to carry out the forming step (S1), the welding step (S2), and the lining step (S3) in this order. Alternatively, the forming step (S1), the lining step (S3), and the welding step (S2) may be performed in this order. That is, after the lining 30 of the stainless steel plate is provided on the base material 11 side of the clad steel 10, the corrosion-resistant metal 20 may be formed on the edge surface 10c of the clad steel 10.

[0053] (Addendum) The structure and welding method according to the above embodiment can be understood, for example, as follows. (1) A steel structure according to one embodiment of the present disclosure includes: A clad steel including a composite material and a base material, A corrosion-resistant metal is overlaid and welded onto the edge surface of the clad steel, A chamfer is formed on a corner of the edge surface, the corner being on the side opposite to the cladding material. It is characterized by:

[0054] According to the steel structure having the above-mentioned configuration, the corrosion resistance of the edge surface of the clad steel can be improved.

[0055] (2) In the steel structure described in (1) above, The base material is provided with a lining of a stainless steel plate, In a direction perpendicular to the extending direction of the edge surface and the thickness direction of the base material, the distance from the corrosion-resistant metal end, which is the end of the corrosion-resistant metal opposite the edge surface, to the end of the stainless steel plate on the edge surface side may be shorter than the distance from the corrosion-resistant metal end to the end of the chamfered portion opposite the edge surface.

[0056] According to the steel structure having the above configuration, the amount of stainless steel plate used for the lining can be reduced.

[0057] (3) In the steel structure described in (2) above, In the chamfered portion, the corrosion-resistant metal may be sandwiched between the stainless steel plate and the chamfered portion when viewed along the direction in which the laminated material and the base material are arranged.

[0058] According to the steel structure having the above-mentioned configuration, it is possible to more reliably prevent components of the base material from being mixed with the corrosion-resistant metal of the lining.

[0059] According to the steel structure having the above configuration, it is possible to achieve low costs.

[0060] (4) In the steel structure according to any one of (1) to (3) above, The edge surface may include an edge surface of the laminated material and an edge surface of the base material.

[0061] According to the steel structure having the above-mentioned configuration, the corrosion resistance of the edge surface of the clad steel can be more reliably ensured.

[0062] (5) In the steel structure described in (4) above, The edge surface of the laminated material and the edge surface of the base material may be at the same position in a direction perpendicular to the extending direction of the edge surface and the plate thickness direction of the base material.

[0063] According to the steel structure having the above configuration, the amount of overlay welding can be reduced.

[0064] (6) In the steel structure according to any one of (1) to (5) above, The steel structure is a steel plate, The cladding material is provided on one surface of the steel plate, The chamfered portion may be formed on the other surface of the steel plate.

[0065] According to the steel structure having the above configuration, the corrosion resistance of the steel plate including the clad steel can be improved.

[0066] (7) In the steel structure according to any one of the above (1) to (6), The steel structure is a steel pipe, the cladding material forms an outer peripheral surface of the steel pipe, The chamfered portion may be formed on the inner peripheral surface side of the steel pipe.

[0067] According to a steel structure having the above configuration, it is possible to prevent components of the base material from mixing with the corrosion-resistant metal from the edge surface on the inner surface side of the steel pipe and affecting the surface of the corrosion-resistant metal.

[0068] (8) An overlay welding method according to one aspect of the present disclosure includes: A method for overlay welding of clad steel including a clad material and a base material, A forming step of forming a chamfered portion on a part of the edge surface of the clad steel; a welding step of overlay-welding a corrosion-resistant metal onto the edge surface; a lining step of providing a lining of a stainless steel plate on the base material side; Equipped with The chamfered portion is formed at a corner of the base material on the edge surface side, opposite to the cladding material. It is characterized by:

[0069] According to the overlay welding method having the above-mentioned configuration, the corrosion resistance of the edge surface of the clad steel can be improved. [Industrial Applicability]

[0070] According to the steel structure and overlay welding method of the present disclosure, the corrosion resistance of the edge surface of clad steel can be improved. Therefore, the present disclosure is extremely useful industrially. [Explanation of symbols]

[0071] 1 Steel structures 10 Clad Steel 11 Base material 12 Laminated material 13 Chamfered part 10c Edge 20 Corrosion-resistant metals (overlay welds) 30 Lining

Claims

1. A clad steel including a composite material and a base material, A corrosion-resistant metal is overlaid and welded onto the edge surface of the clad steel, A chamfer is formed on a corner of the edge surface, the corner being on the side opposite to the cladding material. A steel structure characterized by:

2. The base material is provided with a lining of a stainless steel plate, In a direction perpendicular to the extending direction of the edge surface and the plate thickness direction of the base material, the distance from an end of the corrosion-resistant metal that is an end of the corrosion-resistant metal opposite to the edge surface to an end of the stainless steel plate on the edge surface side is shorter than the distance from the end of the corrosion-resistant metal to an end of the chamfered portion opposite to the edge surface.

2. The steel structure according to claim 1 .

3. In the chamfered portion, the corrosion-resistant metal is sandwiched between the stainless steel plate and the chamfered portion when viewed along a direction in which the laminated material and the base material are arranged.

3. The steel structure according to claim 2.

4. The edge surface includes an edge surface of the laminated material and an edge surface of the base material, 4. The steel structure according to claim 1, wherein the steel structure is a steel structure having a slab.

5. The edge surface of the laminated material and the edge surface of the base material are at the same position in a direction perpendicular to the extension direction of the edge surface and the plate thickness direction of the base material, 5. The steel structure according to claim 4.

6. The steel structure is a steel plate, The cladding material is provided on one surface of the steel plate, The chamfered portion is formed on the other surface of the steel plate.

4. The steel structure according to claim 1, wherein the steel structure is a steel structure having a slab.

7. The steel structure is a steel pipe, the cladding material forms an outer peripheral surface of the steel pipe, The chamfered portion is formed on the inner peripheral surface side of the steel pipe.

4. The steel structure according to claim 1, wherein the steel structure is a steel structure having a slab.

8. A method for overlay welding of clad steel including a clad material and a base material, A forming step of forming a chamfered portion on a part of the edge surface of the clad steel; a welding step of overlay-welding a corrosion-resistant metal onto the edge surface; a lining step of providing a lining of a stainless steel plate on the base material side; Equipped with The chamfered portion is formed on a corner of the base material on the edge surface side, opposite to the cladding material. A method of overlay welding.

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