Method for repairing metal plate conveyance roll, and repaired metal plate conveyance roll

Abstract

To provide a method for repairing a metal plate conveyance roll capable of restoring the diameter of a trunk part into a predetermined size without causing the distortion of the trunk part and being regenerated as a metal plate conveyance roll including a spray coating excellent in pushing performance resistance, corrosion prevention performance and adhesion.SOLUTION: A method for repairing a metal plate conveyance roll comprises steps of: thermally spraying a SUS based material to form a thermal spraying padding coating having a coating thickness of 1-6 mm in a part or all of the area of the trunk part of a metal plate conveyance roll; filling pores in the thermal spraying padding coating with a resin based filler; and thermally spraying a WC cermet material on the thermal spraying padding coating to form a WC cermet coating.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a method for repairing a metal plate conveying roll and a repaired metal plate conveying roll.

Background Art

[0002] Metal plate conveying rolls such as bridle rolls, looper rolls, and steering rolls used in metal plate manufacturing plants gradually wear during use, and the diameter of the body portion becomes smaller. When the diameter (diameter) of the body portion of the metal plate conveying roll becomes smaller than a predetermined value, it is usually discarded. On the other hand, it has been proposed to repair the body portion of the roll so that the metal plate conveying roll with a reduced diameter can be used again.

[0003] For example, Patent Document 1 proposes a method for repairing the body portion using a welding build-up. Specifically, a method has been proposed in which a welding build-up is applied spirally without gaps from one end to the other end of the worn roll surface, and after the entire surface is built up, the unevenness due to the build-up is ground to finish the roll with a flat regular outer diameter.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, since the amount of heat applied to the roll by the welding build-up is large, when the body portion of the metal plate conveying roll is repaired using the welding build-up, there is a risk that heat during welding accumulates in the roll, causing distortion in the roll.

[0006] The present invention has been made in view of such circumstances, and an object thereof is to provide a method for repairing a metal plate conveying roll that can reproduce the metal plate conveying roll without causing distortion by repairing using thermal spraying build-up, and can improve the indentation resistance performance, corrosion prevention performance, and adhesion performance that may be problems in repairing using thermal spraying build-up. Another object is to reduce the environmental load by reusing the used metal plate conveying roll without discarding it.

Means for Solving the Problems

[0007] (1) The method for repairing a metal plate conveying roll of the present invention includes: a step of thermally spraying a SUS-based material onto a part or all of the circumferential portion of the metal plate conveying roll to form a thermally sprayed build-up film having a film thickness of 1 to 6 mm; a step of filling the pores in the thermally sprayed build-up film with a resin-based filler after forming the thermally sprayed build-up film; a step of thermally spraying a WC cermet material onto the thermally sprayed build-up film to form a WC cermet film. This repair method is a method for repairing a metal plate conveying roll whose circumferential portion diameter has become smaller due to wear or the like.

[0008] According to this method for repairing a metal plate conveying roll, the diameter of the circumferential portion can be restored to a predetermined dimension without causing distortion in the circumferential portion, and it can be regenerated as a metal plate conveying roll having a thermally sprayed film excellent in indentation resistance performance, corrosion prevention performance, and adhesion performance. Hereinafter, in this specification, when simply referred to as a roll, it means a metal plate conveying roll unless otherwise specified.

[0009] (2) In the method for repairing a metal plate conveying roll according to (1) above, it is preferable that the WC cermet material is composed of WC-Co, WC-CrC-Ni, or WC-Co-Cr.

[0010] (3) In the method for repairing a metal plate conveying roll according to (1) and (2) above, it is preferable that the film thickness of the WC cermet film is 30 to 500 μm.

[0011] (4) The repair method of the metal plate conveying roll of (1) to (3) above preferably includes a step of filling the pores in the WC cermet film with a resin-based filler after forming the WC cermet film.

[0012] (5) The repair method of the metal plate conveying roll of (1) to (4) above preferably includes a step of forming a bond coat by thermal spraying before forming the sprayed build-up film.

[0013] (6) In the repair method of the metal plate conveying roll of (5) above, the material of the bond coat preferably consists of an alloy containing 40% by mass or more of Ni.

[0014] (7) In the repair method of the metal plate conveying roll of (1) to (6) above, the diameter of the barrel portion is preferably 900 mm or more.

[0015] (8) The repaired metal plate conveying roll of the present invention has a sprayed build-up film made of a SUS-based material with a film thickness of 1 to 6 mm in a part or all of the area of the barrel portion, the pores in the sprayed build-up film are filled with a resin-based filler, and a WC cermet film is provided on the sprayed build-up film.

[0016] (9) For the repaired metal plate conveying roll of (8) above, the diameter of the barrel portion is preferably 900 mm or more.

Advantages of the Invention

[0017] According to the present invention, it is possible to restore the metal plate conveying roll to a predetermined diameter dimension without generating strain in the barrel portion, and to regenerate it as a metal plate conveying roll having a sprayed film excellent in indentation resistance, corrosion prevention performance, and adhesion.

Brief Description of the Drawings

[0018]

Figure 1

Figure 2

Figure 3

Figure 4

Embodiments for Carrying Out the Invention

[0019] Hereinafter, embodiments of the present invention will be described. In the following embodiments, a metal plate conveying roll (hereinafter, also simply referred to as "conveying roll") used in a metal plate manufacturing factory such as a steel plate will be described. Note that the present invention is not limited to the following embodiments. In the repair method according to the embodiment of the present invention, a used conveying roll whose trunk part dimension has become smaller due to wear is restored as a conveying roll having a trunk part with a predetermined dimension and having a thermal spraying coating excellent in indentation resistance, corrosion prevention performance, and adhesion.

[0020] (Object to be repaired) Examples of the conveying roll to be repaired include a bridle roll, a looper roll, a steering roll, etc.

[0021] FIG. 1 is a front view of the conveying roll 10. The conveying roll 10 includes a columnar trunk part 11 for conveying a steel plate and a roll shaft 12 for rotating the conveying roll 10. As time of use passes, the circumferential surface 11a of the trunk part 11 of the conveying roll 10 that comes into contact with the steel plate wears, and the diameter (diameter) of the trunk part 11 becomes smaller. When the diameter of the trunk part 11 of the conveying roll becomes smaller than a predetermined dimension, the use is stopped, and then it is repaired or discarded.

[0022] As a method for repairing the conveying roll 10, a method using welding build-up is known (Patent Document 1). In the method using welding build-up, there is a risk of causing distortion in the barrel portion. On the other hand, in the repair method according to the embodiment of the present invention, the roll can be repaired without causing distortion.

[0023] (Repair method) An embodiment of the repair method will be described. The object to be repaired is a conveying roll whose barrel diameter has become smaller due to wear. The barrel portion of the conveying roll is made of a steel material such as high-carbon chromium bearing steel (SUJ2, etc.), for example. Although a surface layer made of a different composition may remain on a part of the peripheral surface of the barrel portion, the roll to be repaired usually has the steel material exposed on the peripheral surface of the barrel portion. In addition, the repair method according to the embodiment of the present invention may be performed multiple times. Therefore, in the repair for the second time and later, the sprayed build-up coating film sprayed in the previous repair may remain on the peripheral surface of the barrel portion of the roll to be repaired. Hereinafter, in the description of the embodiment of the repair method, the barrel portion of the repair target with a reduced diameter is also referred to as the barrel portion to be repaired.

[0024] <First Embodiment of the Repair Method> FIG. 2 is a partially enlarged cross-sectional view showing the vicinity of the surface layer (for example, region A in FIG. 1) of the barrel portion 11 of the conveying roll (repaired metal plate conveying roll) reproduced through the repair method according to the present embodiment. Here, an embodiment in which the steel barrel body is used as the barrel portion to be repaired will be described.

[0025] (1) A SUS-based material is sprayed onto the barrel portion to be repaired (barrel body) 21 whose roll diameter has become smaller due to wear to form a sprayed build-up coating film 22. Examples of the spraying for forming the sprayed build-up coating film 22 include wire-type frame spraying, high-speed frame spraying, etc.

[0026] Examples of the SUS-based material include SUS430, SUS420, SUS410, SUS304, SUS316, SUS316L, etc. Spraying a SUS-based material to form a sprayed build-up coating film 22 is advantageous in terms of thick film formation, improvement of corrosion resistance, and prevention of film peeling due to having a coefficient of linear expansion close to that of the base material. As the SUS-based material, SUS420 and SUS410 are preferred.

[0027] The film thickness of the sprayed build-up coating film 22 is 1 mm or more and 6 mm or less. By forming the sprayed build-up coating film 22 with such a thickness, it is possible to ensure the film thickness required for dimensional restoration of the barrel part of the roll. If the film thickness of the sprayed build-up coating film 22 is less than 1 mm, dimensional restoration of the barrel part may be insufficient. On the other hand, if the film thickness of the sprayed build-up coating film 22 exceeds 6 mm, there is a risk of cracks occurring in the formed film. The film thickness of the sprayed build-up coating film 22 is preferably 3 mm or more and 5 mm or less.

[0028] (2) A step of filling the pores in the sprayed build-up coating film 22 formed in the above (1) with a resin-based filler is performed. Here, the sprayed build-up coating film 22 with a film thickness of 1 to 6 mm formed in the above (1) has pores in the film. When there are pores in the sprayed build-up coating film 22 in this way, there is a concern that the barrel part 11 of the conveying roll may corrode, and there is also a concern that dents may occur on the surface of the sprayed build-up coating film 22 when a load is applied to the sprayed build-up coating film 22. Therefore, by filling the pores in the sprayed build-up coating film 22 with a film thickness of 1 to 6 mm with an elastically deformable resin-based filler, the resin-based filler filled in the pores can absorb the strain and impact when a load is applied to the sprayed build-up coating film 22, so that the occurrence of dents on the surface of the sprayed build-up coating film 22 can be suppressed. That is, the indentation resistance performance of the sprayed build-up coating film 22 is improved. In addition, corrosion of the barrel part 11 of the conveying roll can be suppressed. Also, the adhesion between the sprayed build-up coating film 22 and the part adjacent to the sprayed build-up coating film 22 (the repaired barrel part 21 and the bond coat 24 described later) is improved.

[0029] Examples of the resin-based filler include epoxy resin, silicone resin, polyester resin, acrylic resin, and the like. Examples of methods for filling the resin-based filler include methods such as brushing, air spray gun, airless gun, dipping, etc. At this time, by adjusting the temperature and viscosity of the resin-based filler, it is possible to easily fill the pores in the sprayed build-up coating film 22 with the resin-based filler. By such a method, a sprayed build-up coating film 22 filled with the resin-based filler in the pores is formed. Note that the sprayed build-up coating film 22 may be subjected to a finishing treatment such as polishing according to the application.

[0030] (3) A WC cermet material is sprayed onto the sprayed build-up coating film 22 filled with the resin-based filler in the pores to form a WC cermet film 23. By forming the WC cermet film 23, the indentation resistance performance of the outer peripheral surface of the body portion 11 of the repaired conveying roll is further improved. Examples of the spraying for forming the WC cermet film 23 include plasma spraying, high-speed flame spraying, etc.

[0031] The WC cermet material may be any material that contains hard particles made of WC and a binder metal. The WC cermet material is preferably composed of WC-Co, WC-CrC-Ni, or WC-Co-Cr. By using these WC cermet materials, a WC cermet film 23 with extremely excellent indentation resistance performance can be formed.

[0032] The film thickness of the WC cermet film 23 is, for example, 30 μm or more and 500 μm or less. The WC cermet film 23 with such a thickness has extremely excellent indentation resistance performance. On the other hand, if the film thickness of the WC cermet film 23 is less than 30 μm, the impact resistance of the WC cermet film 23 may be insufficient, and if the film thickness exceeds 500 μm, cracks may occur in the WC cermet film 23. The film thickness of the WC cermet film 23 is more preferably 50 μm or more and 350 μm or less.

[0033] (4) Fill the pores in the WC cermet coating 23 formed in the above (3) with a resin-based filler. Thereby, corrosion generated between the sprayed build-up coating 22 and the WC cermet coating 23 can be suppressed.

[0034] Examples of the resin-based filler include the same materials as described above. As a method of filling the resin-based filler, the same procedure as described above may be performed. Through this process, a WC cermet coating 23 filled with a resin-based filler in the pores is formed. Note that the WC cermet coating 23 may be subjected to finishing treatment such as polishing according to the application.

[0035] The repair method according to this embodiment goes through such a process, thereby restoring the diameter of the barrel portion 11 of the roll and regenerating it as a conveying roll having a sprayed coating 22 excellent in indentation resistance, corrosion prevention performance, and adhesion. Here, since the above repair method performs repair using spraying, the heat accumulated in the barrel portion 11 of the roll during the build-up process can be reduced compared to the case of forming a build-up coating by welding. Therefore, in the repair method according to this embodiment, it is possible to avoid the occurrence of strain due to heat in the barrel portion 11. Further, by filling the pores in the sprayed build-up coating 22 with a resin-based filler having a film thickness of 1 to 6 mm, the indentation resistance of the sprayed build-up coating 22 is improved. Also, corrosion of the barrel portion 11 can be suppressed. In addition, the adhesion between the sprayed build-up coating 22 and the adjacent portion is improved. Also, by forming a WC cermet coating 23 on the sprayed build-up coating 22, the indentation resistance of the outer peripheral surface of the barrel portion 11 of the repaired conveying roll becomes even better.

[0036] In this embodiment, the sprayed build-up coating 22 and the WC cermet coating 23 may be formed over the entire circumferential surface of the repaired barrel portion 21, or may be formed only on a part of the circumferential surface of the repaired barrel portion 21. When only a part of the body portion 11 is worn and the diameter becomes smaller, the spray build-up coating film 22 and the WC cermet coating film 23 may be formed only on the worn portion of the peripheral surface of the body portion 11, or the entire peripheral surface of the body portion 11 may be polished according to the diameter of a partially worn portion, and the spray build-up coating film 22 and the WC cermet coating film 23 may be formed on the entire peripheral surface of the body portion 11. The larger the repair range is, the larger the amount of strain due to heat becomes. Therefore, the higher the ratio of the repair range to the entire peripheral surface of the body portion 21 to be repaired is, the stronger the effect of the present invention is exhibited. A part of the peripheral surface of the body portion 21 to be repaired may be 50% or more, 80% or more, or 90% or more of the entire peripheral surface of the body portion 21 to be repaired.

[0037] <Second Embodiment of Repair Method> FIG. 3 is a partially enlarged cross-sectional view showing the vicinity of the surface layer (for example, region A in FIG. 1) of the body portion 11' of the transport roll (repaired metal plate transport roll) reproduced through the repair method according to the present embodiment. The same members as those in the first embodiment (FIG. 2) are denoted by the same reference numerals. The repair method according to the present embodiment is different from the first embodiment in that it has a step of forming a bond coat 24 before forming the spray build-up coating film 22.

[0038] (1) A bond coat 24 is formed on the body portion 21 to be repaired of the roll by spraying. Thereby, the adhesion between the body portion 21 to be repaired and the spray build-up coating film 22 described later is further improved. Examples of the spraying for forming the bond coat 24 include wire-frame spraying, high-speed frame spraying, and the like.

[0039] As the spraying material for forming the bond coat 24, an alloy containing 40 mass% or more of Ni is preferably used from the viewpoint of excellent adhesion to the steel body portion 21 to be repaired and the spray build-up coating film 22 made of a SUS-based material. Examples of the alloy containing Ni include NiAl alloy and NiCr alloy. Examples of the NiAl alloy and NiCr alloy include 95Ni5Al, 80Ni20Al, 80Ni20Cr, 50Ni50Cr, and the like.

[0040] From the viewpoint of ensuring good adhesion, the thickness of the bond coat 24 is preferably 30 μm or more and 150 μm or less. If the thickness of the bond coat 24 is less than 30 μm, the adhesion between the steel repair body 21 and the sprayed build-up coating 22 described below may be insufficient. On the other hand, if the thickness of the bond coat 24 exceeds 150 μm, the residual stress increases and the adhesion may decrease.

[0041] (2) Next, in the same manner as in the steps (1) to (4) of the first embodiment of the repair method, a sprayed build-up coating 22 filled with a resin-based filler in the pores is formed on the bond coat 24, and further, a WC cermet coating 23 filled with a resin-based filler in the pores is formed on the sprayed build-up coating 22.

[0042] <Other Embodiments of the Repair Method> In the embodiments of the repair method of the present invention, the step of filling the pores in the WC cermet coating 23 with a resin-based filler is not an essential step but an optional step. Therefore, in the first embodiment and the second embodiment, the step of filling the pores in the WC cermet coating 23 with a resin-based filler may be omitted. However, from the viewpoint of improving the corrosion prevention performance, it is preferable to perform the step of filling the pores in the WC cermet coating 23 with a resin-based filler.

[0043] (Repaired Metal Plate Conveying Roll) <First Embodiment of the Repaired Metal Plate Conveying Roll> Next, embodiments of the repaired metal plate conveying roll of the present invention (hereinafter, also simply referred to as "repaired conveying roll") will be described. The repaired conveying roll of the present embodiment has the configuration shown in FIG. 2.

[0044] The repaired conveying roll according to the present embodiment is provided with a sprayed build-up coating 22 made of a SUS-based material and a WC cermet coating 23 on a part or the whole of the body. The body portion 11 of this repaired conveying roll has a cylindrical steel body main body 21, a sprayed build-up coating film 22 provided on the outer peripheral surface of the body main body 21, and a WC cermet film 23. The body main body 21 is a steel material whose diameter has become smaller than when unused due to wear or the like.

[0045] It is preferable that the diameter of the body portion of the repaired conveying roll is 900 mm or more, and more preferably 1100 mm or more. Even if the diameter of the body portion of the repaired conveying roll is 900 mm or more, and further 1100 mm or more, since it is repaired using spraying, the amount of heat storage is small and the strain of the body main body 21 is small. When replacing a used roll with a new one, especially when the diameter of the body portion is large (for example, 900 mm or more), the cost burden is large. However, if repaired as described above, such a burden can be significantly reduced. Moreover, the film thickness of the sprayed build-up coating film 22 is 1 to 6 mm.

[0046] The pores in the sprayed build-up coating film 22 are filled with a resin-based filler. Thereby, the indentation resistance performance of the sprayed build-up coating film 22 is improved. Also, corrosion of the body portion 11 can be suppressed. Further, the adhesion between the body main body 21 of the roll and the sprayed build-up coating film 22 is improved.

[0047] Specific examples of the resin-based filler include the same ones as those adopted in the embodiment of the repair method of the present invention.

[0048] On the sprayed build-up coating film 22 of the repaired conveying roll, a WC cermet film 23 is provided. Thereby, the indentation resistance performance of the repaired conveying roll is further improved. The preferable material and thickness of the WC cermet film 23 are the same as those adopted in the embodiment of the repair method of the present invention.

[0049] The WC cermet coating 23 is filled with a resin-based filler in the pores within the WC cermet coating 23. In this case, corrosion occurring between the sprayed build-up coating 22 and the WC cermet coating can be suppressed. Specific examples of the resin-based filler include the same ones as those employed in the embodiment of the repair method of the present invention.

[0050] The repaired conveying roll according to the embodiment of the present invention is suitable as a roll used with a winding angle of 90 degrees or more. The above-mentioned repaired conveying roll is excellent in indentation resistance. Therefore, even for a roll with a large contact surface pressure, dents are less likely to occur on the outer peripheral surface of the roll (barrel part).

[0051] FIG. 4 is a diagram for explaining the winding angle of the repaired conveying roll. FIG. 4 shows a cross-sectional view of a cross-section perpendicular to the axial direction of the repaired conveying roll in the use state. The winding angle of the repaired conveying roll refers to the angle θ formed by a line segment connecting the roll center O and one end P1 and a line segment connecting the roll center O and the other end P2, when one end in the circumferential direction of the roll is P1 and the other end is P2 in the range where the steel sheet 1 is in contact with the roll 10.

[0052] The above-mentioned repaired conveying roll is, for example, a roll used in the atmosphere. Specific examples of the above-mentioned repaired conveying roll include, for example, bridle rolls, looper rolls, steering rolls, etc. Specific examples of the above-mentioned repaired conveying roll include, for example, conveying rolls for conveying steel sheets. Also, since a resin-based filler is used in the above-mentioned repaired conveying roll, from the viewpoint of the heat-resistant temperature of the resin-based filler, the repaired conveying roll is preferably used, for example, in a temperature environment of 200°C or lower.

[0053] <Other embodiments of the repaired conveying roll> The repaired conveying roll according to the embodiment of the present invention may be provided with a bond coat 24 between the barrel body 21 and the sprayed build-up coating 22. The bond coat 24 is preferably a film formed by thermal spraying. The preferred material and thickness of the bond coat 24 are the same as those employed in the embodiments of the repair method of the present invention.

[0054] The repaired transfer roll according to the embodiment of the present invention includes a WC cermet film 23. The pores in the WC cermet film 23 of the repaired transfer roll according to the embodiment of the present invention may or may not be filled with a resin-based filler.

[0055] In the repair method of the transfer roll of the present invention and the repaired transfer roll, the thicknesses of the bond coat 24, the spray build-up film 22, and the WC cermet film 23 are measured using a micrometer after each film is applied.

[0056] (Evaluation Test) The following shows the evaluation tests conducted to evaluate the embodiments of the present invention and the results thereof. Here, a push-in test, an adhesion test, and a corrosion test were conducted to evaluate the performance.

[0057] (Examples 1 to 3 and Comparative Examples 1 to 4) For the test pieces used in the push-in test and the corrosion test, a spray build-up film and a WC cermet film were formed on a steel plate (made of SUJ2) with a length of 50 mm × width of 50 mm × thickness of 10 mm by the following method to obtain test pieces. For the test pieces used in the adhesion test, a spray build-up film and a WC cermet film were formed on the end face of a round bar (made of SS400) with a diameter of 25 mm × length of 50 mm by the following method to obtain test pieces. The thickness of the spray build-up film was 3.5 mm, and the thickness of the WC cermet film was the thickness shown in Tables 1 and 2. In Examples 1 to 3 and Comparative Example 2, the pores in the spray build-up film were filled with epoxy resin, and in Examples 2 and 3 and Comparative Example 4, the pores in the WC cermet film were filled with epoxy resin.

[0058] <Formation of Spray Build-up Film> Type of thermal spraying: Wire frame thermal spraying Spraying material: SUS420J2

[0059] <Formation of WC cermet film> Spraying type: High-speed frame spraying Spraying material: WC-20CrC-7Ni

[0060] <Filling of resin-based filler> Treatment method: Brush coating Filler: Epoxy resin

[0061] <Pushing-in test> Test pieces with the sprayed film (sprayed build-up film + WC cermet film) shown in Table 1 were prepared. Using a universal testing machine, an SUJ2 steel ball (φ5mm, HS62 - 67) was pushed into the surface of the test piece at 5mm / s and 5kN, and the damage depth was measured. The results are shown in Table 1.

[0062]

Table 1

[0063] <Adhesion test> Test pieces with the sprayed film (sprayed build-up film + WC cermet film) shown in Table 2 were prepared, and the adhesion of the sprayed film was measured by a method conforming to JIS H8402:2004. According to the method of JIS H8402, the test piece was attached to a universal testing machine and pulled at a pulling speed of 1mm / min to obtain the tensile fracture load. The results are shown in Table 2. In all test cases, fracture occurred within the sprayed build-up film.

[0064] <Corrosion test (CAST test)> Test pieces with the sprayed film (sprayed build-up film + WC cermet film) shown in Table 2 were prepared, and a corrosion test (CAST test) of the sprayed film (sprayed build-up film + WC cermet film) was carried out by a method conforming to JIS H8502:1999. The test solution prepared by the method conforming to JIS H8502 (a solution obtained by adding cupric chloride dihydrate to 5% NaCl + 0.027% CuCl2) was sprayed onto the sprayed coating of the test piece in an environment of 50°C.

[0065] The spraying of the test solution was continued for 96 hours, and then the corrosion resistance of the sprayed coating was evaluated according to the following criteria. The results are shown in Table 2. <Evaluation Criteria> A: No corrosion products were observed. B: The corrosion products occupied 20% or less of the surface of the test piece. C: The corrosion products occupied 50% or more of the surface of the test piece.

[0066]

Table 2

[0067] As shown in Table 1, it was clarified that the indentation resistance performance was improved by filling the pores in the sprayed build-up coating with a resin-based filler. Also, it was clarified that the indentation resistance performance was further improved by forming a WC cermet coating on the sprayed build-up coating. As shown in Table 2, it was clarified that by filling the pores in the sprayed build-up coating with a resin-based filler, corrosion was reduced and adhesion was improved. Also, it was clarified that corrosion was reduced by filling the pores in the WC cermet coating with a resin-based filler.

[0068] From the above, it was found that the sprayed coating of the present invention has sufficient indentation resistance, adhesion, and corrosion resistance. Also, since the sprayed build-up has a smaller thermal influence on the base material compared to the welded build-up, according to the present invention, sufficient indentation resistance, adhesion, and corrosion resistance can be ensured and repaired without causing distortion.

Industrial Applicability

[0069] The repair method of the repaired conveying roll of the present invention and the repaired conveying roll of the present invention can be used in a manufacturing factory of metal plates such as steel plates.

Explanation of Symbols

[0070] 1 Steel plate 10 Metal plate conveying roll 11, 11′ Barrel part 11a Peripheral surface 12 Roll shaft 21 Barrel part body (barrel part to be repaired) 22 Sprayed build-up coating 23 WC cermet coating 24 Bond coat

Claims

1. A step of spraying a SUS-based material onto a part or all of the body of a metal plate conveying roll to form a sprayed build-up coating with a film thickness of 1 to 6 mm; After forming the sprayed build-up coating, a step of filling pores in the sprayed build-up coating with a resin-based filler; A step of spraying a WC cermet material onto the sprayed build-up coating to form a WC cermet coating; A method for repairing a metal plate conveying roll having the above steps.

2. The method for repairing a metal plate conveying roll according to Claim 1, wherein the WC cermet material is composed of WC-Co, WC-CrC-Ni, or WC-Co-Cr.

3. The method for repairing a metal plate conveying roll according to Claim 1 or 2, wherein the film thickness of the WC cermet coating is 30 to 500 μm.

4. After forming the WC cermet coating, a step of filling pores in the WC cermet coating with a resin-based filler; The method for repairing a metal plate conveying roll according to Claim 1 or 2 having the above step.

5. Before forming the sprayed build-up coating, a step of forming a bond coat by spraying; The method for repairing a metal plate conveying roll according to Claim 1 or 2 having the above step.

6. The method for repairing a metal plate conveying roll according to Claim 5, wherein the material of the bond coat is an alloy containing 40% by mass or more of Ni.

7. The method for repairing a metal plate conveying roll according to Claim 1 or 2, wherein the diameter of the body is 900 mm or more.

8. Having a sprayed build-up coating made of a SUS-based material with a film thickness of 1 to 6 mm on a part or all of the body; The pores in the sprayed build-up coating are filled with a resin-based filler; Having a WC cermet coating on the sprayed build-up coating; A repaired metal plate conveying roll.

9. The repaired metal plate conveying roll according to Claim 8, wherein the diameter of the body is 900 mm or more.

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