A method for repairing a damaged wear-resistant coating sprayed on a surface of a metal material

Abstract

The application discloses a kind of repair methods of wear-resistant coating damaged after being sprayed on the surface of metal material, comprising the following steps: one, the surface of metal material is treated by spraying, to obtain coating metal material;Two, coating metal material is used, to obtain coating damaged metal material, by high-low temperature cycle thermal shock treatment, to obtain the metal material separated from coating;Three, new coating is prepared on the metal material separated from coating by laser cladding treatment, to complete coating repair.The application is damaged after being used in wear-resistant coating, and the coating is completely separated in large area by high-low temperature cycle thermal shock, to avoid potential risks such as fatigue microcracks still existing in coating after repair, finally, new coating of same composition is prepared again by laser cladding technology, to use the scrapped parts again, the new coating repaired by laser has uniform and dense structure, the new coating has good use effect, and the repair cost is low, with high reliability.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of sprayed coating, and particularly relates to a method for repairing a damaged wear-resistant coating sprayed on a metal material surface. BACKGROUND

[0002] Spraying is a solid additive manufacturing process that uses kinetic energy from a pressurized gas stream to deposit metal and non-metal powders onto a substrate. When the particles collide with the underlying material, the intense plastic deformation causes the particles to eject along the edges, and the destruction of the thin oxide layer along the interface allows clean surface metals to come into contact with each other, thereby promoting bonding through metallurgical and mechanical mechanisms. In recent years, with the continuous breakthroughs in equipment and materials, the continuous improvement and optimization of the spraying process, and the continuous improvement of the spraying quality, the spraying technology has been more widely applied in the engineering field.

[0003] Due to the continuous rise of modern mechanization, parts treated by surface spraying will fail due to wear and tear during long-term use. The laser repair technology can restore the performance of the parts, prolong the service life, reduce the life cycle cost, save raw materials, reduce environmental pollution, and form a new industry. Laser technology is widely used in repairing flat and shaft parts due to its low cost and high efficiency.

[0004] The repair of damaged coating parts first requires mechanical processing. Therefore, the machining of the damaged coating on the surface of the part is an important part of the repair technology and is indispensable. However, the machining of the coating is not the same as the machining of ordinary bulk materials. First, the bonding strength of the coating is limited, especially at the edge, which is a weak part that cannot withstand excessive cutting stress, and is prone to coating peeling or individual particle shedding due to improper machining. Second, the sprayed coating generally has high hardness and wear resistance, and the hard points and pores in the coating will cause the cutting force of machining to be in a vibration state, generating a large cutting force and cutting heat, causing abnormal wear of the cutting tool, and higher strength requirements for the cutting tool. Third, the coating is generally thin, and the machining allowance is small, so improper machining can easily cause size tolerance.

[0005] Therefore, it is necessary to develop a more convenient method for completely removing the damaged coating and repairing it. SUMMARY

[0006] The technical problem solved by the present application is to provide a method for repairing a damaged wear-resistant coating sprayed on a metal material surface, in view of the above-mentioned deficiencies of the prior art.

[0007] To solve the above technical problem, the technical solution adopted by the present application is as follows:

[0008] Step one: clean and grit blast the surface of the metal material, then use spraying treatment to deposit a metal-based ceramic composite wear-resistant coating on the surface of the metal material to obtain a coated metal material;

[0009] Step two: use the coated metal material obtained in step one to obtain a coated metal material with damaged coating, then use high-low temperature cyclic thermal shock treatment to completely separate the mechanically bonded coating on the surface of the metal material to obtain a metal material with separated coating;

[0010] Step three: use laser cladding to prepare a new coating with the same composition as the wear-resistant coating in step one on the metal material with separated coating obtained in step two to complete the coating repair.

[0011] The present application cleans and grit blasts the surface of the metal material substrate to ensure stable connection between the metal-based ceramic composite wear-resistant coating and the metal material. The spraying treatment causes the spraying particle beam to collide with the surface of the metal material, and the collision-deformation-condensation-shrinkage-filling process is continuously carried out. The particles are bonded together layer by layer, and finally a metal-based ceramic composite wear-resistant coating with a certain thickness is deposited on the surface of the metal material. The coated metal material obtained by the present application is used in its applicable field. The coating will inevitably be damaged during use. The present application uses high-low temperature cyclic thermal shock treatment to completely separate the mechanically bonded coating on the surface of the metal material, thereby avoiding potential risks such as fatigue micro-cracks in the repaired coating. Then, a new coating with the same composition as the wear-resistant coating is prepared by laser cladding. The new coating repaired by laser has a uniform and dense structure, good use effect, low repair cost, and high reliability.

[0012] The application discloses a repairing method for a damaged wear-resistant coating sprayed on a metal material surface, and belongs to the technical field of metal material surface coating.

[0013] The application discloses a repairing method for a damaged wear-resistant coating sprayed on a metal material surface, and belongs to the technical field of metal material surface coating.

[0014] Step 101: placing the metal material with damaged coating into water at 90-100 DEG C and stopping for 30-180 seconds to obtain high-temperature treated material;

[0015] Step 102: immediately placing the high-temperature treated material obtained in step 101 into liquid nitrogen and stopping for 30-180 seconds to obtain low-temperature treated material;

[0016] Step 103: repeatedly performing steps 101 and 102 until the whole coating is largely peeled off. In the conventional cutting and grinding method for repairing damaged parts, the interface of the sprayed coating is mainly mechanically combined, and the thermal expansion coefficient difference between the surface metal ceramic composite coating and the metal bonding layer is used to cause the coating to be peeled off due to thermal stress. The principle is that, between the interface of the surface metal ceramic composite coating and the metal bonding layer, the coating volume expands less and is subjected to tensile stress, and the metal volume expands more and is subjected to compressive stress in the heating stage; in the cooling stage, the coating is subjected to compressive stress and the metal is subjected to tensile stress, and through repeated heating and cooling processes, the cyclic thermal stress in the coating is continuously accumulated, the original microcracks, pores and other defects at the interface are continuously extended and expanded, and finally the sprayed coating is largely and integrally peeled off.

[0017] The application discloses a repairing method for a damaged wear-resistant coating sprayed on a metal material surface, and belongs to the technical field of metal material surface coating.

[0018] Step 201: performing laser remelting treatment on the surface of the metal material with peeled-off coating to obtain laser remelted metal material;

[0019] Step 202, the laser remelting metal material obtained in step 201 is subjected to laser cladding in a synchronous powder feeding mode, and the parameters of the laser cladding meet: the laser power is 4000W-10000W, the positive defocusing is 10mm-20mm, the powder feeding rate is 20g / min-40g / min, the scanning speed is 450mm / min-1000mm / min, and the overlap rate is not less than 70%. The interface bonding mode is improved to metallurgical bonding by adopting the laser remelting treatment, the laser remelting layer is thin, has a flattening effect on the surface, the surface organization of the metal material is refined, then the laser cladding is adopted, the low heat input can be realized and any thickness can be realized, a dense coating is formed, and complete metallurgical bonding is achieved.

[0020] The above-mentioned method for repairing the damaged wear-resistant coating sprayed on the metal material surface, characterized in that, after the new coating of the same composition and metallurgical bonding is prepared on the metal material separated from the coating in step three, the new coating is mechanically processed. The new coating is mechanically processed after the new coating is prepared, so that the new coating returns to the original size and can continue to be used in the original field.

[0021] Compared with the prior art, the present application has the following advantages:

[0022] 1. The present application adopts spraying treatment, and the plastic base is uniformly distributed with ceramic phases in the form of particles and with appropriate size, successfully realizing the combination of the advantages of metal and ceramic, preparing a new metal-based ceramic composite coating which has the advantages of metal strength and toughness, ceramic high-temperature resistance, wear resistance and corrosion resistance, and greatly widening the application range of metal materials and ceramic materials.

[0023] 2. Before repairing the damaged sprayed coating, the present application needs to clean the surface to remove the fatigue layer, but due to the uneven surface and high hardness, the machining difficulty is large, resulting in low processing efficiency and high cost. The high-low temperature oscillation experiment adopted in the present application can remove the damaged coating, and the method is simple and has strong practicability.

[0024] 3. Whether the damaged fatigue layer on the surface of the part is completely removed or not has an important influence on the reliability of subsequent repair. If the removal allowance is small, micro cracks may exist on the surface, and in the use process after the repair is completed, the hidden fatigue micro cracks may expand, resulting in coating failure. The high-low temperature oscillation experiment in the present application can effectively and naturally screen out hidden fatigue micro cracks and make them expand into macro cracks, so that the damaged coating naturally falls off, the damaged fatigue layer on the surface of the part can be completely removed, and the trend of crack formation of the new coating can be effectively reduced.

[0025] 4. This invention uses laser remelting combined with laser cladding to obtain a completely dense metallurgical bonding coating. The laser-repaired layer has a uniform and dense structure, is smooth and flat, has strong adhesion to the substrate, and has good wear resistance, increasing the reliability of metal material reuse. The wear-resistant coating repaired using this invention has good performance, low repair cost, and high reliability.

[0026] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the device used in the high and low temperature cyclic thermal shock treatment of the present invention.

[0028] Figure 2 This is a cross-sectional schematic diagram of the coated metal material prepared in step one of Embodiment 1 of the present invention.

[0029] Figure 3 This is a cross-sectional schematic diagram of the new coating prepared in step three of Embodiment 4 of the present invention. Detailed Implementation

[0030] Figure 1 This is a schematic diagram of the device used in the high and low temperature cyclic thermal shock treatment of the present invention. Figure 1 As can be seen from the above, in the high and low temperature cyclic thermal shock treatment, the present invention uses a robotic arm to subject the damaged metal material to high and low temperature cyclic thermal shock in boiling water and liquid nitrogen.

[0031] Example 1

[0032] This embodiment includes the following steps:

[0033] Step 1: The surface of 45# steel is cleaned and roughened by sandblasting. A mixture of high melting point superhard WC ceramic powder and Ni metal powder with a volume ratio of 1:10 is selected as the spraying material. A cold spraying surface treatment process is adopted. The working gas is compressed N2, the gas preheating temperature is 500℃, the carrier gas pressure is 3.5MP, the powder feed rate is 70g / min, the gun speed is 500mm / s, and the spraying distance is 25mm. A metal-based ceramic composite wear-resistant coating is deposited on the surface of 45# steel to obtain the coated metal material.

[0034] Step 2: Use the coated metal material obtained in Step 1 to obtain a metal material with a damaged coating. Then, use a robotic arm to place the metal material with a damaged coating into water at 90℃~100℃ for 30 seconds. Immediately after that, use a robotic arm to remove it and place it in a liquid nitrogen environment for 30 seconds. Repeat the above steps 42 times to completely remove the mechanically bonded coating on the surface of 45# steel over a large area, obtaining a metal material with the coating removed.

[0035] Step three, laser remelting the metal material with detached coating obtained in step two, to obtain laser remelted metal material, then laser cladding the laser remelted metal material in a way of synchronous powder feeding, to prepare a new coating with same composition as the wear-resistant coating in step one and metallurgical bonding, machining the new coating to complete the coating repair; the parameters of laser cladding meet: laser power is 4000W, positive defocusing is 20mm, powder feeding rate is 20g / min, scanning speed is 500mm / min, and lap rate is 70%.

[0036] It is detected that step three in this embodiment forms a new coating with metallurgical bonding on the surface of the metal material with detached coating, which not only restores the outer dimensions, but also makes the performance reach or even exceed that of the original coating.

[0037] Figure 2 The cross-sectional view of the coating metal material prepared in step one in this embodiment shows that Figure 2 It can be seen that there is a sprayed coating with a certain thickness on the surface of the 45# steel, and the coating has a large number of pores.

[0038] Example 2

[0039] This embodiment includes the following steps:

[0040] Step one, cleaning and sandblasting the surface of GH3030 alloy and roughening the surface, selecting a mixture of high-melting-point superhard BN ceramic powder and Ni metal powder with a volume ratio of 1:4 as the sprayed material, using plasma spraying surface treatment process, current is 800A, spray gun distance is 100mm, main gas flow is 104SCFH, auxiliary gas flow is 2SCFH, powder feeding amount is 40g / min, spray gun moving distance is 600mm / s, and step distance is 3mm, to deposit a metal-based ceramic composite wear-resistant coating on the surface of GH3030 alloy, to obtain a coating metal material;

[0041] Step two, using the coating metal material obtained in step one to obtain a coating-damaged metal material, then placing the coating-damaged metal material in water at 90℃-100℃ using a mechanical arm, stopping for 60s, immediately taking out and placing in a liquid nitrogen environment using a mechanical arm after completion, stopping for 60s, and repeating the above steps 28 times, to completely detach the large-area mechanically bonded coating on the surface of GH3030 alloy, to obtain a metal material with detached coating;

[0042] Step three, laser remelting the metal material with detached coating obtained in step two to obtain laser remelted metal material, then laser cladding the laser remelted metal material in a way of synchronous powder feeding to prepare a new coating of same composition as the wear-resistant coating in step one, which is metallurgically combined, and mechanically process the new coating to complete coating repair; the laser cladding parameters meet: laser power is 6000W, positive defocusing is 10mm, powder feeding rate is 25g / min, scanning speed is 500mm / min, and lap rate is 80%.

[0043] It is detected that step three in the embodiment forms a new coating on the surface of the metal material with detached coating, which is metallurgically combined with the surface of the metal material, so that the shape size is restored and the use performance is even better than the original coating.

[0044] Example 3

[0045] The embodiment includes the following steps:

[0046] Step one, cleaning and grit blasting the surface of 45# steel, selecting a mixture of high-melting-point superhard diamond powder and Co metal powder with a volume ratio of 1:6 as the spraying material, adopting supersonic flame spraying surface treatment process, spraying distance is 190mm, gas pressure is 0.4MPa, powder feeding amount is 45g / min, depositing a metal-based ceramic composite wear-resistant coating on the surface of 45# steel to obtain a coated metal material;

[0047] Step two, using the coated metal material obtained in step one to obtain a coated metal material with damaged coating, then placing the coated metal material with damaged coating in water at 90℃-100℃ by a mechanical arm for 180s, immediately taking out and placing in a liquid nitrogen environment after completion, stopping for 180s, and repeating the above steps for 33 times, so that the large-area mechanically combined coating on the surface of 45# steel is completely detached to obtain a metal material with detached coating;

[0048] Step three, laser remelting the metal material with detached coating obtained in step two to obtain laser remelted metal material, then laser cladding the laser remelted metal material in a way of synchronous powder feeding to prepare a new coating of same composition as the wear-resistant coating in step one, which is metallurgically combined, and mechanically process the new coating to complete coating repair; the laser cladding parameters meet: laser power is 8000W, positive defocusing is 15mm, powder feeding rate is 30g / min, scanning speed is 750mm / min, and lap rate is 75%.

[0049] It is detected that step three in the embodiment forms a new coating on the surface of the metal material with detached coating, which is metallurgically combined with the surface of the metal material, so that the shape size is restored and the use performance is even better than the original coating.

[0050] Example 4

[0051] The embodiment comprises the following steps:

[0052] Step one, the surface of 45# steel is cleaned and sandblasted, a mixture of high-melting-point superhard WC ceramic powder and Ni metal powder with a volume ratio of 1:8 is selected as the spraying material, a plasma spraying surface treatment process is adopted, the current is 700 A, the spraying gun distance is 120 mm, the main gas flow is 91 SCFH, the auxiliary gas flow is 1 SCFH, the powder feeding amount is 20 g / min, the spraying gun moving distance is 1000 mm / s, and the step distance is 3 mm, a metal-based ceramic composite wear-resistant coating is deposited on the surface of 45# steel to obtain a coated metal material;

[0053] Step two, the coated metal material obtained in step one is used to obtain a coated damaged metal material, then the coated damaged metal material is placed in water at 90-100°C by a mechanical arm for 60 s, immediately after completion, the mechanical arm is used to take out and place in a liquid nitrogen environment for 60 s, and the above steps are repeated for 25 times, so that the mechanically combined coating on the surface of 45# steel is completely separated in a large area to obtain a metal material separated from the coating;

[0054] Step three, the metal material separated from the coating obtained in step two is subjected to laser remelting treatment to obtain a laser remelted metal material, then the laser remelted metal material is subjected to laser cladding in a synchronous powder feeding manner to prepare a new coating of the same composition as the wear-resistant coating in step one and metallurgically combined with the metal material surface, the new coating is subjected to mechanical processing, and the coating repair is completed; the laser cladding parameters satisfy: laser power is 10000 W, positive defocusing is 15 mm, powder feeding rate is 40 g / min, scanning speed is 1000 mm / min, and overlap rate is 85%.

[0055] It is detected that in the embodiment, step three forms a new coating on the surface of the metal material separated from the coating, which is metallurgically combined with the metal material surface, can not only restore its external dimensions, but also make its use performance reach or even exceed that of the original coating.

[0056] Figure 3 The new coating prepared in step three of the embodiment is schematically shown in a cross-section view, from which it can be seen that the new coating has a compact organization form and is well metallurgically combined with the 45# steel material, the organization is compact and has no obvious defects, and the enlarged view of the arrow pointing position is the new coating. Figure 3

[0057] ​The above merely describes preferred embodiments of the present application, and is not intended to limit the present application. Any simple modification, change, and equivalent variation of the above embodiments according to the technical essence of the present application are still within the protection scope of the technical scheme of the present application.

Claims

1. A method of repairing a damaged wear-resistant coating sprayed on a surface of a metal material, characterized by, It comprises the following steps: Step one, cleaning and sandblasting the surface of the metal material, then using spray treatment to deposit a metal-based ceramic composite wear-resistant coating on the surface of the metal material to obtain a coated metal material; the spray material used in the spray treatment is a mixture of high-melting-point superhard ceramic powder and metal powder in a volume ratio of 1:4-10, the high-melting-point superhard ceramic powder is tungsten carbide powder, diamond powder or cubic boron nitride powder, the metal powder is Fe, Ni or Co, and the spray treatment is thermal spraying or cold spraying; Step two, using the coated metal material obtained in step one to obtain a coated damaged metal material, then treating the metal material surface mechanically combined coating through high-low temperature cycle thermal shock treatment to completely separate a large area of the coating, and obtaining a metal material separated from the coating; Step three, using laser cladding treatment to prepare a new coating of the same composition as the wear-resistant coating in step one on the metal material separated from the coating obtained in step two, and completing the coating repair; the process of laser cladding treatment comprises the following steps: Step 201, using laser remelting treatment to treat the surface of the metal material separated from the coating, and obtaining a laser remelted metal material; Step 202, using laser cladding with synchronous powder feeding on the laser remelted metal material obtained in step 201, and the parameters of the laser cladding meet: laser power is 4000W-10000W, positive defocusing is 10mm-20mm, powder feeding rate is 20g / min-40g / min, scanning speed is 450mm / min-1000mm / min, and overlapping rate is not less than 70%.

2. A method of repairing a damaged wear-resistant coating sprayed on a surface of a metal material according to claim 1, characterized in that, The process of high-low temperature cycle thermal shock treatment in step two comprises the following steps: Step 101, placing the coated damaged metal material in water at 90-100℃ and stopping for 30-180s to obtain a high-temperature treated material; Step 102, immediately placing the high-temperature treated material obtained in step 101 in liquid nitrogen and stopping for 30-180s to obtain a low-temperature treated material; Step 103, repeatedly performing steps 101 and 102 until the coating falls off in a large area.

3. A method of repairing a damaged wear-resistant coating applied to a metal material surface according to claim 1, characterized in that, After preparing the new coating of the same composition as the coating on the metal material separated from the coating in step three, the new coating is subjected to mechanical processing.

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