Laser cladding coating for electric hardware and cladding method thereof

Abstract

The present application relates to a kind of laser cladding coating for electric power fittings and its cladding method, the coating includes the following components by mass percentage: 0~1% rare earth oxide, 3~50% carbide and the balance of Ni60;The proportion of carbide and rare earth oxide in the technical scheme provided by the present application not only improves the strengthening hardness and wear resistance of the surface strengthening coating for fittings, but also reduces the cost, and is convenient for use.

Description

Technical Field

[0001] The invention relates to surface strengthening of electric power fittings, and in particular to a laser cladding coating for electric power fittings and a cladding method thereof. Background Art

[0002] Power fittings, which connect and assemble components within power systems and within them, are essential components of transmission lines. Wind is one of the primary threats to the safe operation of transmission lines. Accidents such as tower collapses, line breaks, wind deflection, flashover, and insulator disconnection caused by strong winds and sandstorms are common. Accidents caused by fitting wear are particularly detrimental to transmission lines. Therefore, improving the wear resistance of fitting surfaces is crucial to ensure the safe operation of transmission lines.

[0003] The inventors have discovered that applying laser cladding technology to electrical hardware significantly improves its surface mechanical properties and exhibits high interfacial bonding strength. Further research has revealed that a high content of hard phase is necessary to improve hardness and wear resistance. However, excessive hard phase content or a large difference in hard phase content between cladding layers can easily lead to interfacial bonding defects. Considering the purification, modification, and alloying effects of rare earth elements on metals, adding a certain particle size of rare earth elements to the cladding layer can significantly improve surface cladding quality while also being relatively inexpensive to produce, facilitating widespread adoption. Summary of the Invention

[0004] In response to the shortcomings of the existing technology, the present invention provides a method for improving the interface bonding strength, hardness and wear resistance of the cladding layer by gradiently controlling the proportion of carbides and rare earth oxides in the components of the cladding layer on the surface of electrical hardware, thereby obtaining a cladding layer with good density and no surface cracks.

[0005] The purpose of the present invention is achieved by adopting the following technical solutions:

[0006] A laser cladding coating for electric power hardware comprises the following components by mass percentage: 0-1% rare earth oxide, 3-50% carbide and the balance Ni60.

[0007] Furthermore, the carbide is WC; and the rare earth oxide is CeO2.

[0008] Furthermore, the Ni60 includes the following components by mass percentage: 0.6-1% C, 14-18% Cr, 3.5-5.5% Si, 0-10% Fe, 0-1% Mo, 0-1% Mn, 3.0-4.5% B and the balance Ni.

[0009] Furthermore, the particle size of the Ni60 is -200 mesh to +270 mesh;

[0010] The particle size of the CeO2 is 5 to 30 nm;

[0011] The particle size of the WC is -200 mesh to +325 mesh.

[0012] Furthermore, the coating has at least two layers, and from the bottom layer to the surface layer, the CeO2 content decreases layer by layer, and the WC content increases layer by layer.

[0013] Furthermore, the coating comprises three layers,

[0014] The bottom layer, the middle layer and the surface layer respectively include the following components by mass percentage: 0.1-0.3% CeO2, 5-15% WC, and the balance Ni60;

[0015] 0.05-0.2% CeO2, 15-25% WC, the balance Ni60; and

[0016] 25-35% WC, balance Ni60.

[0017] A method for laser cladding coating for electric power fittings, the method comprising the following steps:

[0018] (1) Clean the surface of electrical fittings;

[0019] (2) preparing a coating; and

[0020] (3) Laser cladding.

[0021] Furthermore, the laser cladding includes supplying coating in a synchronous powder feeding manner.

[0022] Furthermore, the laser cladding includes performing the laser cladding under a protective atmosphere of 10 to 15 L / min, a powder feeding rate of 12 to 25 g / min, a laser power of 3500 to 6000 W, a scanning speed of 200 to 600 mm / min, and a spot diameter of (3 to 8) mm×(3 to 8) mm.

[0023] Compared with the closest existing technology, the technical solution provided by the present invention has the following excellent effects:

[0024] (1) The technical solution provided by the present invention eliminates the interface bonding defects caused by excessive hard phase content or large difference in hard phase content by gradually increasing the proportion of hard phase WC, thereby obtaining a metal surface with excellent wear resistance; the addition amount of rare earth oxide in the technical solution of the present invention not only reduces the cost but also improves the interface bonding strength; by matching the two components and their contents, a metal tool with an excellent cladding layer is obtained at a low cost.

[0025] (2) The cladding technology provided by the present invention can achieve complete metallurgical bonding reaction, high interface bonding strength, and fine and dense structure. The laser cladding process is highly controllable and easy to promote and apply on an industrial scale. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of the coating and power connection hardware substrate structure provided by the invention. DETAILED DESCRIPTION

[0027] The technical solutions provided by the present invention are described clearly and completely below with reference to the accompanying drawings. It is apparent that the embodiments described are only a portion of the embodiments of the present invention, not all of them. Any modifications made by a person of ordinary skill in the art based on the embodiments of the present invention fall within the scope of protection of the present invention for which application is pending.

[0028] Example 1:

[0029] (1) Purify the surface of No. 35 steel electrical fittings

[0030] The surface of the hardware base is polished with sandpaper, and rust and oil are removed.

[0031] (2) Preparation of coating

[0032] Mechanically mix the following layers of coating material in percentage by mass:

[0033] Bottom layer: 0.2% CeO2, 5% WC, balance Ni60;

[0034] Middle layer: 0.1% CeO2, 15% WC, balance Ni60;

[0035] Surface layer: 25% WC, balance Ni60;

[0036] Among them, Ni60: 0.6% C, 15% Cr, 4% Si, 4% Fe, 0.1% Mo, 0.1% Mn, 3.1% B, balance Ni;

[0037] The particle size of Ni60 is -200 mesh to +270 mesh, the particle size of powder WC is -200 mesh to +325 mesh, and the particle size of powder CeO2 is 20 nm.

[0038] (3) Laser cladding

[0039] The relationship between the matrix and each layer is as follows Figure 1 As shown, under an argon protective atmosphere with a flow rate of 15 L / min, each layer of coating in the powder feeder is delivered in a synchronous powder feeding manner, wherein: laser power 5000 W, scanning speed 500 mm / min, powder feeding rate 18 g / min and spot diameter 5 mm×5 mm.

[0040] Example 2:

[0041] (1) Purify the surface of 35CrMo steel electrical fittings

[0042] The surface of the hardware base is polished with sandpaper, and rust and oil are removed.

[0043] (2) Preparation of coating

[0044] Mechanically mix the following layers of coating material in percentage by mass:

[0045] Bottom layer: 0.3% CeO2, 10% WC, balance Ni60;

[0046] Middle layer: 0.2% CeO2, 20% WC, balance Ni60;

[0047] Surface layer: 35% WC, balance Ni60.

[0048] Among them, Ni60: 0.6% C, 15% Cr, 4% Si, 4% Fe, 0.1% Mo, 0.1% Mn, 3.1% B, balance Ni;

[0049] The particle size of Ni60 is -200 mesh to +270 mesh, the particle size of powder WC is -200 mesh to +325 mesh, and the particle size of powder CeO2 is 20 nm.

[0050] (3) Laser cladding

[0051] The relationship between the matrix and each layer is as follows Figure 1 As shown, under an argon protective atmosphere with a flow rate of 15L / min, each layer of coating in the powder feeder is delivered in a synchronous powder feeding manner, wherein: laser power 5000W, scanning speed 200mm / min, powder feeding rate 15g / min and spot diameter 5mm×5mm.

[0052] Example 3:

[0053] (1) Purify the surface of Q345R steel electrical fittings

[0054] The surface of the hardware base is polished with sandpaper, and rust and oil are removed.

[0055] (2) Preparation of coating

[0056] Mechanically mix the following layers of coating material in percentage by mass:

[0057] Bottom layer: 0.2% CeO2, 3% WC, balance Ni60;

[0058] Middle layer: 0.1% CeO2, 10% WC, balance Ni60;

[0059] Surface layer: 20% WC, balance Ni60.

[0060] Among them, Ni60: 0.6% C, 15% Cr, 4% Si, 4% Fe, 0.1% Mo, 0.1% Mn, 3.1% B, balance Ni;

[0061] The particle size of Ni60 is -200 mesh to +270 mesh, the particle size of powder WC is -200 mesh to +325 mesh, and the particle size of powder CeO2 is 20 nm.

[0062] (3) Laser cladding

[0063] The relationship between the matrix and each layer is as follows Figure 1 As shown, under an argon protective atmosphere with a flow rate of 15L / min, each layer of coating in the powder feeder is delivered in a synchronous powder feeding manner, wherein: laser power 5000W, scanning speed 500mm / min, powder feeding rate 15g / min and spot diameter 5mm×5mm.

[0064] The data recorded in the above examples are statistically sorted, and the powder ratios and cladding process parameters of the cladding layers of Examples 1-3 are shown in Table 1:

[0065] Table 1. Cladding layer powder ratios and cladding process parameters of Examples 1-3

[0066]

[0067]

[0068] Performance testing

[0069] According to the test method of GB / T12444-2006 "Metallic material wear test method test ring - test rapid sliding wear test", the wear of the cladding layer of each embodiment is tested under the conditions of load 100N and holding for 15 minutes.

[0070] The hardness of the cladding layer of each embodiment was tested according to the Vickers hardness test method specified in GBT4340.1-2009 "Vickers hardness test method for metallic materials", where the hardness symbol is HV30 and the nominal test force is 294.2N.

[0071] Through microstructural observation, no cracks or pores were found in the cladding layers obtained in the embodiments of the present invention.

[0072] The properties of the cladding layers of Examples 1-3 are listed in Table 2 below:

[0073] Table 2 Cladding layer properties of Examples 1-3

[0074] Example Coating hardness / HV Surface hardness improvement rate / % Wear amount / g Wear resistance improvement rate / % 1 780 90.25 0.16 56.21 2 766 86.75 0.18 52.35 3 741 80.62 0.19 50.78

[0075] The test data of the cladding layers of the above-mentioned embodiments show that the surface hardness of the hardware provided by the technical solution of the present invention reaches up to 780HV, which is more than 80% higher than the hardness of the original surface of the hardware, and the wear amount is less than 0.2g. The wear resistance of the original surface of the power hardware is improved by more than 50%. The microstructure shows that it is small and dense. The laser cladding process is highly controllable, low-cost, and easy to promote and use.

[0076] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered by the scope of protection of the claims of the present invention.

Claims

1. A laser cladding coating for electric power fittings, characterized in that: The coating comprises the following components by mass percentage: 0-1% rare earth oxide, 3-50% carbide and the balance Ni60; Wherein, the carbide is WC; the rare earth oxide is CeO2; The coating has at least two layers, and from the bottom layer to the surface layer, the CeO2 content decreases layer by layer, and the WC content increases layer by layer.

2. The coating according to claim 1, wherein The Ni60 includes the following components by mass percentage: 0.6-1% C, 14-18% Cr, 3.5-5.5% Si, 0-10% Fe, 0-1% Mo, 0-1% Mn, 3.0-4.5% B and the balance Ni.

3. The coating according to claim 1, wherein The particle size of the Ni60 is -200 mesh to +270 mesh; The particle size of the CeO2 is 5 to 30 nm; The particle size of the WC is -200 mesh to +325 mesh.

4. The coating according to claim 1, wherein The coating comprises three layers, The bottom layer, the middle layer and the surface layer respectively include the following components by mass percentage: 0.1-0.3% CeO2, 5-15% WC, and the balance Ni60; 0.05-0.2% CeO2, 15-25% WC, the balance Ni60; and 25-35% WC, balance Ni60.

5. A cladding method for a laser cladding coating for an electric power fitting according to any one of claims 1 to 4, characterized in that: The method comprises the following steps: (1) Clean the surface of electrical fittings; (2) preparing a coating; and (3) Laser cladding; The laser cladding coating comprises the following components by mass percentage: 0-1% rare earth oxide, 3-50% carbide and the balance Ni60; The carbide is WC; the rare earth oxide is CeO2; The coating has at least two layers, and from the bottom layer to the surface layer, the CeO2 content decreases layer by layer, and the WC content increases layer by layer.

6. The method according to claim 5, wherein The laser cladding includes supplying coating in a synchronous powder feeding manner.

7. The method according to claim 6, wherein The laser cladding includes performing the laser cladding under the conditions of 10-15 L / min protective atmosphere, 12-25 g / min powder feeding rate, 3500-6000 W laser power, 200-600 mm / min scanning speed and (3-8) mm×(3-8) mm spot.

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