Repairing method for metal coating on surface of metal matrix and application of repairing method

Abstract

The invention provides a method for repairing a metal coating on the surface of a metal matrix and application of the method, and the method comprises the following steps: (1) determining a damaged area of the metal coating on the surface of the metal matrix, and carrying out sand blasting, cleaning and roughening treatment on the damaged area to obtain an area to be repaired; and (2) the area to be repaired is subjected to thermal spraying treatment, a new metal coating is formed, and repairing is completed. According to the repairing method, the repairing problem of local damage of the metal coating is solved, the coating in the damaged area is completely coated after repairing, the coating is well combined with an original coating, and the overall structure is compact. By repairing the damaged area of the local metal coating, a corrosive medium can be effectively prevented from being in contact with a metal substrate, the protection performance of a metal material is improved, and the overall service life of the coating is prolonged.

Description

Technical Field

[0001] The invention belongs to the technical field of offshore mobile platform coating, and relates to a method for repairing a metal coating on the surface of a metal substrate and application thereof. Background Art

[0002] Ships operating in the marine environment face severe corrosion challenges. Seawater is a strong electrolyte solution that contains a large amount of salt, dissolved oxygen, and various microorganisms, all of which can cause serious corrosion to the metal structure of the ship. In addition, the impact of waves and the attachment of marine organisms can also accelerate the corrosion process of the ship. As an important means of protection, anti-corrosion coatings can effectively isolate the metal structure of the ship from the corrosive medium, delay the occurrence of corrosion, and extend the service life of the ship.

[0003] Anti-corrosion coating can not only protect the ship structure, but also reduce the maintenance cost of the ship. If there are no effective anti-corrosion measures, the ship will continue to suffer from corrosion during use, and frequent repairs and maintenance are required, which will not only consume a lot of time and money, but also affect the normal operation of the ship. A good anti-corrosion coating can maintain its protective performance for a long time, reduce the number of repairs, and reduce maintenance costs. CN118357135A discloses a hull outer plate coating repair method, which is used to re-coat the damaged area of ​​the hull outer plate coating, according to the surface state of the damaged area, use a laser cleaner to clean the damaged area, according to the original coating information, form a transition area surrounding the damaged area on the surface of the original coating, and clean and polish the transition area to form an inclined side, form a repair coating on the damaged area and the transition area, and apply a uniform coating on the repair coating and the original coating to form a topcoat outer layer.

[0004] CN114032538A discloses a method and coating for repairing a worn part of a ship's tail shaft, the method comprising: mixing bronze powder with SiC powder to obtain a mixed powder; using the mixed powder as a spraying material, spraying the pre-treated worn part of the ship's tail shaft by a cold spraying process to obtain a bronze-based composite coating at the worn part; and treating the bronze-based composite coating to complete the repair of the worn part of the ship's tail shaft.

[0005] Although the repair method described in the above scheme reduces the repair cost for local repair, the bonding effect between the repaired coating and the original coating is reduced, and the service life of the coating is shortened. Among the many means of improving the wear resistance and corrosion resistance of the material surface, spraying metal protective coating is one of the important measures to extend the service life of marine oil and gas equipment. However, metal coatings may break and fail, so the coating will be repaired several times during its service. Generally speaking, a "major overhaul" of the coating usually involves completely removing the coating and then applying a new layer of material. The repair method of "completely removing the coating and re-coating" is time-consuming, labor-intensive, and costly. Summary of the invention

[0006] The purpose of the present invention is to provide a method for repairing a metal coating on a metal substrate surface and its application. The repair method of the present invention solves the problem of repairing local damage to the metal coating. After the repair, the coating of the damaged area is completely coated, well combined with the original coating, and the overall structure is dense. By repairing the damaged area of ​​the local metal coating, the contact between the corrosive medium and the metal substrate can be effectively prevented, the protective performance of the metal material can be improved, and the overall life of the coating can be extended.

[0007] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0008] In a first aspect, the present invention provides a method for repairing a metal coating on a surface of a metal substrate, the method comprising the following steps:

[0009] (1) determining the damaged area of ​​the metal coating on the surface of the metal substrate, and performing sandblasting cleaning and roughening treatment on the damaged area to obtain the area to be repaired;

[0010] (2) The repaired area is thermally sprayed to form a new metal coating to complete the repair.

[0011] The present invention performs sandblasting cleaning and roughening treatment on the damaged area of ​​the metal coating, removes the original damaged coating by sandblasting cleaning and roughening treatment, and roughens the surface of the metal-based material by collision, and the roughened surface is stably connected to the sprayed metal droplets by mechanical bonding. During the thermal spraying process, the molten metal droplets collide with the rough surface of the metal material and spread out, stacking layer by layer, and finally forming a metal coating of a certain thickness on the surface of the material, completing the repair of the metal coating.

[0012] Preferably, in step (1), damaged areas of different shapes are regularized and unified before sandblasting and roughening.

[0013] Preferably, the regularization and unification includes regularizing damaged areas of different shapes into simple shapes.

[0014] Preferably, the simple shape includes any one of a rectangle, a circle or an ellipse, or a combination of at least two of them.

[0015] The present invention pre-regulates and unifies the damaged area of ​​the metal coating, and regularizes the complex polygons or irregular shapes into simple graphics for easy subsequent processing.

[0016] Preferably, the sandblasting used in the sandblasting cleaning and roughening treatment in step (1) includes corundum sandblasting and / or diamond grit sandblasting.

[0017] Preferably, the sandblasting cleaning and roughening treatment in step (1) includes cleaning and roughening at an angle of 60° to 80°, for example, 60°, 65°, 70°, 75° or 80°, etc., not limited to the listed values, and other values ​​not listed in the numerical range are also applicable, at a distance of 8 to 12 cm from the damaged area, for example, 8 cm, 9 cm, 10 cm, 11 cm or 12 cm, etc., not limited to the listed values, and other values ​​not listed in the numerical range are also applicable.

[0018] Preferably, the metal substrate is preheated before the thermal spraying treatment in step (2).

[0019] Preferably, the temperature of the preheat treatment is 120°C to 180°C, for example, 120°C, 130°C, 140°C, 150°C, 160°C, 170°C or 180°C, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0020] Preferably, the spraying material used in the thermal spraying process in step (2) is a metal wire that is the same as the original coating material.

[0021] The spraying material used in the thermal spraying process of the present invention can be adjusted according to the type of the original coating. Currently, the commonly used one is the soft magnetic nickel alloy metal wire, namely Inconel 625 metal wire.

[0022] Preferably, the diameter of the metal wire is 1.5-1.8 mm, for example, 1.5 mm, 1.55 mm, 1.6 mm, 1.7 mm or 1.8 mm, etc., but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0023] Preferably, the thermal spraying treatment in step (2) includes plasma spraying.

[0024] Preferably, the single spraying thickness of the thermal spraying treatment in step (2) is 100 to 150 μm, for example: 100 μm, 110 μm, 120 μm, 130 μm, 140 μm or 150 μm, etc., not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0025] In the process of thermal spraying of the present invention, the electric arc melts the metal from its tip, and the molten material is broken up and pushed toward the surface of the substrate by a jet of compressed air or inert gas.

[0026] The thermal spraying treatment described in the present invention can adjust the coating thickness and properties of the repair area by controlling the number of spraying times to meet the use requirements. The material can be cooled between each spraying and the next spraying as needed to avoid large thermal stress affecting the good bonding of the repair coating.

[0027] As a preferred embodiment of the present invention, the repair method comprises the following steps:

[0028] (1) Determine the damaged area of ​​the metal coating on the surface of the metal substrate, regularize and unify the damaged areas of different shapes, and use sandblasting at an angle of 60° to 80° and 8 to 12 cm away from the damaged area to perform cleaning and roughening treatment to obtain the area to be repaired;

[0029] (2) After preheating the area to be repaired at 120°C to 180°C, the area to be repaired is thermally sprayed by plasma spraying, with a single spraying thickness of 100 to 150 μm to form a new metal coating to complete the repair.

[0030] In a second aspect, the present invention provides an application of the repair method as described in the first aspect, wherein the repair method is used to repair local damage to a metal coating on the surface of an offshore mobile platform.

[0031] Preferably, the offshore mobile platform includes a ship and / or a drilling platform.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] (1) The present invention uses sandblasting to remove damaged coatings, which has high removal efficiency. The roughening effect produced during the cleaning process provides a roughened surface for the repair coating, which simplifies the process and saves time. By repairing the damaged area of ​​the local metal coating, the frequency of component replacement is reduced, the service life of the metal material is increased, and the production cost is reduced. At the same time, it is also beneficial to environmental protection, reducing resource waste and environmental pollution.

[0034] (2) The repair method of the present invention solves the problem of repairing local damage to the metal coating. By repairing the local damaged area of ​​the metal coating, the contact between the corrosive medium and the metal substrate can be effectively prevented, the protective performance of the metal material can be improved, and the overall life of the coating can be extended.

[0035] (3) The repair method of the present invention can make the metal material better adapt to the complex working environment by repairing the damaged area of ​​the local metal coating. After the repair, the coating of the damaged area is complete, well combined with the original coating, and the overall structure is dense. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is a diagram of the damaged area of ​​the metal coating on the surface of the metal substrate described in Example 1.

[0037] Figure 2 This is a picture of a new metal coating obtained after repair using the repair method described in Example 1. DETAILED DESCRIPTION

[0038] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0039] The metal coating on the surface of the metal substrate in the embodiments and comparative examples of the present invention is an Inconel 625 metal coating.

[0040] Example 1

[0041] This embodiment provides a method for repairing a metal coating on a metal substrate surface, the method comprising the following steps:

[0042] (1) Determine the damaged area of ​​the metal coating on the surface of the metal substrate, regularize and unify the damaged areas of different shapes, and use a rectangular repair shape. The damaged area map is as follows: Figure 1 As shown, corundum sandblasting was used at an angle of 75° to perform cleaning and roughening treatment 10 cm away from the damaged area to obtain the area to be repaired;

[0043] (2) After the metal substrate is preheated to 150°C, an Inconel 625 metal wire with a diameter of 1.6 mm is used for thermal spraying on the repaired area by atmospheric plasma spraying. The single spraying thickness is 120 μm. The spraying is repeated twice to form a new metal coating and complete the repair. After the spraying is completed, the new metal coating is naturally cooled to room temperature. Figure 2 shown.

[0044] Example 2

[0045] This embodiment provides a method for repairing a metal coating on a metal substrate surface, the method comprising the following steps:

[0046] (1) Determine the damaged area of ​​the metal coating on the surface of the metal substrate, regularize and unify the damaged areas of different shapes, adopt a rectangular repair shape, use diamond grit sandblasting at an angle of 60°, and perform cleaning and roughening treatment at a distance of 8 cm from the damaged area to obtain the area to be repaired;

[0047] (2) After the metal substrate is preheated to 120°C, the area to be repaired is thermally sprayed with an Inconel625 metal wire with a diameter of 1.5 mm using atmospheric plasma spraying. The single spraying thickness is 100 μm, and the spraying is repeated twice to form a new metal coating to complete the repair. After spraying, the surface is naturally cooled to room temperature.

[0048] Example 3

[0049] This embodiment provides a method for repairing a metal coating on a metal substrate surface, the method comprising the following steps:

[0050] (1) Determine the damaged area of ​​the metal coating on the surface of the metal substrate, regularize and unify the damaged areas of different shapes, adopt a rectangular repair shape, use corundum sandblasting at an angle of 80°, and perform cleaning and roughening treatment at a distance of 12 cm from the damaged area to obtain the area to be repaired;

[0051] (2) After the metal substrate is preheated to 120°C, an Inconel 625 metal wire with a diameter of 1.8 mm is used for thermal spraying on the repaired area by atmospheric plasma spraying. The single spraying thickness is 150 μm. The spraying is repeated twice to form a new metal coating and complete the repair. After spraying, the surface is naturally cooled to room temperature.

[0052] Example 4

[0053] The only difference between this embodiment and embodiment 1 is that the sandblasting angle of the cleaning and roughening treatment in step (1) is 50°, and the other conditions and parameters are exactly the same as those in embodiment 1.

[0054] Example 5

[0055] The only difference between this embodiment and embodiment 1 is that the sandblasting angle of the cleaning and roughening treatment in step (1) is 90°, and the other conditions and parameters are exactly the same as those in embodiment 1.

[0056] Example 6

[0057] The only difference between this embodiment and embodiment 1 is that the distance between the sandblasting for the cleaning and roughening treatment in step (1) and the damaged area is 5 cm, and the other conditions and parameters are exactly the same as those in embodiment 1.

[0058] Example 7

[0059] The only difference between this embodiment and embodiment 1 is that the distance between the sandblasting for the cleaning and roughening treatment in step (1) and the damaged area is 15 cm, and the other conditions and parameters are exactly the same as those in embodiment 1.

[0060] Example 8

[0061] The only difference between this embodiment and embodiment 1 is that the preheating temperature in step (2) is 100° C., and the other conditions and parameters are exactly the same as those in embodiment 1.

[0062] Example 9

[0063] The only difference between this embodiment and embodiment 1 is that the preheating temperature in step (2) is 200° C., and the other conditions and parameters are exactly the same as those in embodiment 1.

[0064] Comparative Example 1

[0065] The only difference between this comparative example and Example 1 is that step (1) adopts conventional laser cleaning, and the other conditions and parameters are exactly the same as those in Example 1.

[0066] Performance Test:

[0067] Sample bonding strength test:

[0068] The bonding strength of the samples was tested in accordance with the national standard GB / T 8642-2002 Thermal Spraying - Determination of Tensile Bond Strength. Three parallel samples were prepared for each example for testing.

[0069] Sample bonding strength test:

[0070] Three parallel samples were prepared for each example for testing. A conventional three-electrode electrolytic cell was used, with a saturated calomel electrode (SCE) as the reference electrode, a platinum sheet as the counter electrode, and a sample (exposed surface area of ​​1 cm 2 ) as the working electrode. All electrochemical tests were carried out in 3.5wt% NaCl solution at room temperature. Before the test, the exposed sample surface was wet-grinded with 100 mesh, 200 mesh, 500 mesh, 1000 mesh and 2000 mesh sandpaper, then washed with deionized water and dried with air flow. The test results are shown in Table 1:

[0071] Table 1

[0072]

[0073]

[0074] As can be seen from Table 1, from Examples 1-9, the bonding strength of the metal coating obtained by the repair method of the present invention can reach above 38±1MPa, the corrosion potential can reach above -0.725V, and the corrosion current density can reach 3.42×10 -5 A / cm 2 the following.

[0075] By comparing Example 1 with Examples 4-5, it can be seen that in the repair process of the metal coating on the surface of the metal substrate of the present invention, the sandblasting angle of the cleaning and roughening treatment will affect the repair effect. The sandblasting angle of the cleaning and roughening treatment is controlled at 60-80°, and the repair effect is better. If the sandblasting angle of the cleaning and roughening treatment is too small, the impact angle of the abrasive particles on the metal surface is small, which may lead to a low surface roughness. At the same time, too small a sandblasting angle may cause the abrasive particles to be unable to fully contact the coating, and also reduce the removal efficiency. If the sandblasting angle of the cleaning and roughening treatment is too large, the abrasive particles may rebound on the metal surface, reducing the removal efficiency.

[0076] By comparing Example 1 with Examples 6-7, it can be seen that in the repair process of the metal coating on the surface of the metal substrate described in the present invention, the distance between the sandblasting for the cleaning and roughening treatment and the damaged area will affect the repair effect. The repair effect is better when the distance between the sandblasting for the cleaning and roughening treatment and the damaged area is controlled at 8 to 12 cm. If the distance between the sandblasting for the cleaning and roughening treatment and the damaged area is too small, the abrasive may be too concentrated, resulting in local excessive sandblasting, while other areas may not be fully treated. If the distance between the sandblasting for the cleaning and roughening treatment and the damaged area is too large, the impact force of the abrasive will be weakened, making it difficult to effectively remove the coating.

[0077] By comparing Example 1 with Example 8-9, it can be seen that in the repair process of the metal coating on the surface of the metal substrate of the present invention, the preheating temperature will affect the repair effect. The preheating temperature is controlled at 120°C to 180°C, and the repair effect is better. If the preheating temperature is too low, the substrate temperature is low, and the sprayed particles cool quickly after hitting the substrate, the fluidity of the particles deteriorates, and it is difficult to fully fill the pores, resulting in an increase in the porosity in the coating. In addition, the crystallization rate of the sprayed particles is inconsistent during the cooling process, and it is easy to form grains of different sizes and orientations, making the microstructure of the coating complex and uneven. This uneven organization may cause the coating to have unstable performance during use. If the preheating temperature is too high, the organizational structure of the substrate may change, resulting in a decrease in its mechanical properties such as strength and hardness. Excessively high substrate preheating temperature may cause the coating to undergo excessive thermal history during the formation process, resulting in an uneven organizational structure and unstable performance of the coating.

[0078] By comparing Example 1 and Comparative Example 1, it can be seen that the present invention performs sandblasting cleaning and roughening treatment on the damaged area of ​​the metal coating, removes the original damaged coating by sandblasting cleaning and roughening treatment, and the sandblasting roughens the surface of the metal base material through collision, and the roughened surface is stably connected to the sprayed metal droplets through mechanical bonding.

[0079] The applicant declares that the above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention shall fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for repairing a metal coating on a metal substrate surface, characterized in that: The repair method comprises the following steps: (1) determining the damaged area of ​​the metal coating on the surface of the metal substrate, and performing sandblasting cleaning and roughening treatment on the damaged area to obtain the area to be repaired; (2) The repaired area is thermally sprayed to form a new metal coating to complete the repair.

2. The repair method according to claim 1, characterized in that: Step (1) before sandblasting and roughening, the damaged areas of different shapes are regularized and unified; Preferably, the regularization and unification includes regularizing the damaged areas of different shapes into simple shapes; Preferably, the simple shape includes any one of a rectangle, a circle or an ellipse, or a combination of at least two of them.

3. The repair method according to claim 1 or 2, characterized in that: The sandblasting used in the sandblasting cleaning and roughening treatment in step (1) includes corundum sandblasting and / or diamond grit sandblasting.

4. The repair method according to any one of claims 1 to 3, characterized in that: The sandblasting cleaning and roughening treatment in step (1) includes cleaning and roughening at an angle of 60° to 80° and at a distance of 8 cm to 12 cm from the damaged area.

5. The repair method according to any one of claims 1 to 4, characterized in that: Step (2) preheating the metal substrate before the thermal spraying treatment; Preferably, the preheating temperature is 120°C to 180°C.

6. The repair method according to any one of claims 1 to 5, characterized in that: The spraying material used in the thermal spraying process in step (2) is a metal wire that is the same as the original coating material; Preferably, the diameter of the metal wire is 1.5 mm to 1.8 mm.

7. The repair method according to any one of claims 1 to 6, characterized in that: The thermal spraying process in step (2) includes plasma spraying.

8. The repair method according to any one of claims 1 to 7, characterized in that: The single spraying thickness of the thermal spraying treatment in step (2) is 100 to 150 μm.

9. The repair method according to any one of claims 1 to 8, characterized in that: The repair method comprises the following steps: (1) Determine the damaged area of ​​the metal coating on the surface of the metal substrate, regularize and unify the damaged areas of different shapes, and use sandblasting at an angle of 60° to 80° and 8 to 12 cm away from the damaged area to perform cleaning and roughening treatment to obtain the area to be repaired; (2) After preheating the area to be repaired at 120°C to 180°C, the area to be repaired is thermally sprayed by plasma spraying, with a single spraying thickness of 100 to 150 μm to form a new metal coating to complete the repair.

10. An application of the repair method according to any one of claims 1 to 9, characterized in that: The repair method is used to repair local damage to the metal coating on the surface of an offshore mobile platform; Preferably, the offshore mobile platform includes a ship and / or a drilling platform.

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