A multi-layer wear-resistant flux-cored welding rod and its preparation method and application

Abstract

The present invention belongs to the technical field of metal wear-resistant materials, and specifically relates to a multi-layer wear-resistant flux-cored welding rod and its preparation method and application. The multi-layer wear-resistant flux-cored welding rod of the present invention comprises, from the inside to the outside, an inner core, a steel strip layer, a coating layer and a diamond micropowder layer; the inner core is composed of nickel-based solder powder; the coating layer is composed of the following raw materials in percentage by mass: CaF2 30% to 40%, TiO2 35% to 45%, MgO 15% to 25%, Al 4% to 6%. The multi-layer wear-resistant flux-cored welding rod of the present invention can form a wear-resistant layer with higher hardness, and can significantly improve the wear resistance of the substrate and extend the service life of the substrate. It has broad application prospects in the field of wear-resistant layer preparation and wear-resistant layer repair of forged parts.

Description

Technical Field

[0001] The invention belongs to the technical field of metal wear-resistant materials, and in particular relates to a wear-resistant flux-cored welding rod with a multi-layer structure and a preparation method and application thereof. Background Art

[0002] Flux-cored welding rods are composite welding rods formed by wrapping a flux core with an outer steel strip. As a new generation of welding materials, flux-cored welding rods have obvious advantages in welding efficiency, quality, and comprehensive cost. In recent years, they have been widely used in castings and forgings in the fields of engineering machinery, energy and chemical industry, and marine engineering, such as in shield machine cutters and wear-resistant repair of large pressure vessel surfaces.

[0003] As the manufacturing industry develops towards large-scale, heavy-loaded and intelligent, the service conditions of large castings and forgings are more demanding, requiring the workpiece surface to have strong wear resistance and good hardness uniformity. However, there are still technical bottlenecks in the wear-resistant repair of large castings and forgings in China that need to be broken through. Summary of the invention

[0004] To solve the above problems, the purpose of the present invention is to provide a multi-layer wear-resistant flux-cored welding rod, the wear-resistant layer obtained by cladding has high hardness and wear resistance, is easy to use, and has strong adaptability to working conditions.

[0005] The present invention also provides a method for preparing the multi-layer wear-resistant flux-cored welding rod, which has a simple process and is suitable for large-scale production.

[0006] The present invention also provides application of the wear-resistant flux-cored welding rod with the multi-layer structure.

[0007] In order to achieve the above objectives, the multi-layer wear-resistant flux-cored welding rod of the present invention adopts the following technical solution:

[0008] A multi-layer wear-resistant flux-cored welding rod comprises, from the inside to the outside, an inner core, a steel strip layer, a flux layer and a diamond powder layer; the inner core is composed of nickel-based solder powder; the nickel-based solder powder is composed of the following mass percentages: B 2.75%-3.5%, Si 4%-5%, Cr 6%-8%, Fe 2.5%-3.5%, and the remainder is Ni and unavoidable impurities; the flux layer is composed of the following mass percentages of raw materials: CaF2 30%-40%, TiO2 35%-45%, MgO 15%-25%, Al 4%-6%.

[0009] The multi-layer wear-resistant flux-cored welding rod of the present invention comprises an inner core, a steel strip layer, a coating layer and a diamond micropowder layer which are arranged in sequence. Compared with the flux-cored welding rod prepared by directly mixing diamond micropowder with nickel-based solder powder, the present invention adopts a four-layer structure design, which can significantly slow down the carbonization rate of diamond. During welding, due to the high welding energy, if diamond micropowder and nickel-based solder powder are mixed together, the instantaneous high temperature will cause thermal damage to most of the diamonds. In the present invention, the diamonds are pressed into the outer layer, the energy changes in a gradient, and the thermal damage of the diamonds can be significantly reduced.

[0010] Specifically, during the welding process, the internal flux-cored wire of the present invention starts an arc, the nickel-based brazing filler metal powder melts and enters the molten pool, and the external diamond enters the weld and undergoes metallurgical bonding with the molten pool to form a wear-resistant coating. During the reaction process, the third layer of coating of the present invention plays a role in protecting the molten pool. The CaF2 in the coating layer can increase the basicity of the cladding metal, and a large amount of gas generated at the same time covers the arc and the molten pool, reducing the interaction between the molten metal and the air; Al metal, as a reducing agent, can reduce the residual amount of oxygen in the cladding metal and improve the quality of the weld. TiO2 and MgO have the function of adjusting the molten droplet transition morphology, welding spatter and weld bead formation. At the same time, the addition of nickel-based brazing filler metal powder synergistically improves the fluidity, high-temperature oxidation resistance and structural stability of the coating. Further matching the addition of the outer layer of diamond, the hardness of the cladding layer obtained by the flux-cored electrode of the present invention after welding can reach 927 to 1030 HV, and the wear resistance is significantly improved. Furthermore, the multi-layer wear-resistant flux-cored welding rod provided by the present invention can repair the wear-resistant layer on site, is easy to operate, has strong adaptability to working conditions, and is suitable for the preparation and application of metal wear-resistant layers.

[0011] The present invention does not specifically limit the material of the steel strip layer, and a suitable steel strip material can be selected as needed to achieve the wrapping of the inner core. Preferably, the steel strip layer is a low-carbon cold-rolled steel strip. Furthermore, the composition of the low-carbon cold-rolled steel strip is: C content <0.05wt%, Si content <0.03wt%, Mn content of 0.15wt% to 0.25wt%, S and P content <0.03wt%, and the balance is Fe and unavoidable impurities.

[0012] In order to ensure the surfacing strengthening effect, preferably, the particle size of the nickel-based solder powder is 50-60 μm; and in the diamond powder layer, the particle size of the diamond powder is 20-50 μm.

[0013] In specific applications, it is necessary to select a suitable diameter and size of the flux-cored electrode according to the thickness of the weldment. Generally, the thickness of the cladding layer is more suitable at about 5 mm. Therefore, preferably, the diameter of the wear-resistant flux-cored electrode of the multi-layer structure is 3.2 to 4.0 mm.

[0014] The method for preparing the multi-layer wear-resistant flux-cored welding rod of the present invention adopts the following technical scheme:

[0015] A method for preparing a multi-layer wear-resistant flux-cored welding rod comprises the following steps:

[0016] (1) Using steel strip to roll nickel-based brazing powder to form a flux-cored welding wire with a steel strip layer wrapping the inner core;

[0017] (2) using the raw material of the coating layer to prepare the coating coating; and using the diamond micro powder to prepare the diamond coating;

[0018] (3) A coating is applied on the surface of the flux-cored welding wire to obtain a coating layer, and then a diamond coating is applied on the surface of the coating layer to obtain a diamond powder layer, thereby obtaining a wear-resistant flux-cored welding rod with a multi-layer structure.

[0019] The method for preparing the multi-layer wear-resistant flux-cored welding rod of the present invention firstly prepares the flux-cored welding wire by rolling nickel-based brazing filler metal powder inside a steel strip, and then prepares the coating and diamond powder layer by pressure coating. The whole process is simple to operate and is suitable for industrial production.

[0020] The powder filling rate refers to the percentage of the powder mass filled inside to the total mass of the flux-cored welding wire in which the powder is located. The present invention uses a steel strip to wrap nickel-based solder powder to form a flux-cored welding wire. In order to improve the flux core wrapping and strengthening effect, preferably, in step (1), the filling rate of the nickel-based solder powder in the steel strip is 45% to 50%.

[0021] In step (2), the preparation method of the coating and diamond coating can be conventional in the art. For example, water glass is used as an auxiliary material, and the coating layer raw material and diamond powder are respectively prepared into the corresponding coating and diamond coating. The amount of water glass can be adjusted according to the pressure coating requirements.

[0022] In order to optimize the wear-resistant enhancement effect of each layer structure after cladding, further, the ratio of the diameter of the flux-cored welding wire, the thickness of the coating layer, and the thickness of the diamond powder layer is (1.8-2.4): (1.0-1.1): (0.4-0.5).

[0023] In the above method, the coating layer and the diamond powder layer are prepared by pressure coating. The present invention adopts the pressure coating method to prepare the electrode coating and the diamond powder layer, which not only has high production efficiency and fast speed, but also has the advantages of uniform thickness, smoothness, density and stable quality of the layer structure.

[0024] Preferably, the process conditions of the pressure coating are: the wire feeding speed is 5-6 m / min, the coating extrusion volume is 120-160 cm 3 / min.

[0025] The present invention also provides the use of the wear-resistant flux-cored welding rod with the multi-layer structure as described above, specifically, the use of the welding rod as a cladding material in preparing a metal wear-resistant layer by surfacing welding.

[0026] Based on the consideration of improving the hardness and wear resistance of the metal wear-resistant layer, preferably, the surfacing welding is arc surfacing welding or manual surfacing welding; the process parameters of the arc surfacing welding are: welding current of 200-300A, arc voltage of 22-28V, dry elongation of 12-18mm, and welding speed of 20-30cm / min; the process parameters of the manual surfacing welding are: welding current of 120-150A, welding voltage of 22-26V, and welding speed of 11-15cm / min.

[0027] The present invention does not specifically limit the metal material clad by the flux-cored electrode, and is applicable to the preparation of wear-resistant layers or wear-resistant repair of castings and forgings of various materials. For example, the metal material of the castings and forgings can be steel of various types and compositions.

[0028] The present invention uses a multi-layer wear-resistant flux-cored welding rod as a cladding material to prepare a metal wear-resistant layer. The hardness of the obtained wear-resistant layer can reach 927-1030HV, and the wear resistance is significantly improved. It has good application prospects in the field of preparation of metal wear-resistant layers. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic structural diagram of a multi-layer wear-resistant flux-cored welding rod of the present invention;

[0030] in, Figure 1 Middle: 1-inner core, 2-steel belt layer, 3-cored layer, 4-diamond powder layer. DETAILED DESCRIPTION

[0031] The technical scheme of the present invention is further described below in conjunction with specific embodiments. However, it should be understood by those skilled in the art that the following examples are only used to illustrate the present invention and should not be considered as limiting the scope of the present invention. In the following examples, the raw materials involved are conventional commercially available products unless otherwise specified.

[0032] Among them, the structural schematic diagram of the multi-layer wear-resistant flux-cored welding rod of the present invention is as follows Figure 1 shown. Figure 1 In the embodiment, the multi-layer wear-resistant flux-cored electrode comprises, from the inside to the outside, an inner core 1, a steel strip layer 2, a flux layer 3 and a diamond powder layer 4.

[0033] The steel strip used in the following embodiments is a low-carbon cold-rolled steel strip, and its composition is: C content <0.05wt%, Si content <0.03wt%, Mn content of 0.15wt% to 0.25wt%, S, P content <0.03wt%, and the balance is Fe and unavoidable impurities. In other embodiments, the steel strip can also be made of other optional materials that meet the requirements, such as stainless steel.

[0034] The mass percentage composition of the nickel-based solder powder is: B 2.75%-3.5%, Si 4%-5%, Cr 6%-8%, Fe 2.5%-3.5%, and the balance is Ni and inevitable impurities.

[0035] Example 1

[0036] The multi-layer wear-resistant flux-cored electrode of this embodiment includes an inner core, a steel strip layer, a flux layer and a diamond micro-powder layer from the inside to the outside. The inner core is made of nickel-based solder powder; the flux layer is made of the following raw materials in mass percentage: CaF2 40%, TiO2 40%, MgO 15%, Al 5%. The particle size of the nickel-based solder powder is 50 μm; in the diamond micro-powder layer, the particle size of the diamond micro-powder is 20 μm.

[0037] The method for preparing the multi-layer wear-resistant flux-cored welding rod comprises the following steps:

[0038] (1) A nickel-based solder powder is rolled from a steel strip with a thickness of 2 mm, and after various stages of drawing, a flux-cored welding wire is formed in which a steel strip layer wraps a nickel-based solder inner core; wherein the filling rate of the nickel-based solder powder is 46%; and the diameter of the flux-cored welding wire after drawing is 1.8 mm;

[0039] (2) The raw materials for the coating layer are mixed uniformly by a planetary mixer at a speed of 150 r / min for 1 h. Water glass (the mass ratio of sodium silicate to water in water glass is 1:10) is added to the uniformly mixed coating layer powder. The mass ratio of the coating layer powder to water glass is 5:1. After mixing for 2 h, a coating coating is obtained. In addition, water glass is added to diamond micropowder at a mass ratio of diamond micropowder to water glass of 10:1. The mixture is mixed for 2 h to obtain a uniform diamond coating.

[0040] (3) Using a pressure coating machine, the process parameters are: wire feeding speed: 5.3m / min, coating extrusion volume: 150cm 3 / min, the coating prepared in step (2) is press-coated on the surface of the flux-cored wire with a thickness of 1.0 mm, and then a layer of diamond coating is press-coated on the surface of the coating layer with the same process parameters with a thickness of 0.4 mm. After press-coating, it is dried at 60°C to obtain a multi-layer wear-resistant flux-cored electrode with a diameter of 3.2 mm.

[0041] The application of the multi-layer wear-resistant flux-cored electrode as a cladding material in arc cladding to prepare a metal wear-resistant layer. The arc cladding adopts a MAG cladding process. Q235 steel is used as the substrate, and the surface of the substrate is treated by a sandblasting process to remove impurities on the surface of the substrate; then the MAG cladding process is used to clad the obtained multi-layer wear-resistant flux-cored electrode on the surface of the Q235 steel substrate; the cladding process parameters are: 80% Ar + 20% CO2 shielding gas, welding current of 300A, arc voltage of 22V, dry elongation of 15mm, and welding speed of 30cm / min.

[0042] Example 2

[0043] The multi-layer wear-resistant flux-cored electrode of this embodiment includes an inner core, a steel strip layer, a flux layer and a diamond micro-powder layer from the inside to the outside. The inner core is made of nickel-based solder powder; the flux layer is made of the following raw materials in mass percentage: CaF2 35%, TiO2 40%, MgO 20%, Al 5%. The particle size of the nickel-based solder powder is 60 μm; in the diamond micro-powder layer, the particle size of the diamond micro-powder is 50 μm.

[0044] The method for preparing the multi-layer wear-resistant flux-cored welding rod comprises the following steps:

[0045] (1) A nickel-based brazing filler metal powder is rolled from a steel strip having a thickness of 2 mm, and the steel strip layer is drawn at various levels to form a flux-cored welding wire having an inner core wrapped therein; wherein the filling rate of the nickel-based brazing filler metal powder is 45%; and the diameter of the flux-cored welding wire after drawing is 2.0 mm;

[0046] (2) The raw materials for the coating layer are mixed uniformly by a planetary mixer at a speed of 150 r / min for 1 h. Water glass (the mass ratio of sodium silicate to water in water glass is 1:10) is added to the uniformly mixed coating layer powder. The mass ratio of the coating layer powder to water glass is 5:1. After mixing for 2 h, a coating coating is obtained. In addition, water glass is added to diamond micropowder at a mass ratio of diamond micropowder to water glass of 10:1. The mixture is mixed for 2 h to obtain a uniform diamond coating.

[0047] (3) Using a pressure coating machine, the process parameters are: wire feeding speed: 5.3m / min, coating extrusion volume: 150cm 3 / min, the coating prepared in step (2) is press-coated on the surface of the flux-cored wire with a thickness of 1.0 mm, and then a layer of diamond coating is press-coated on the surface of the coating layer with the same process parameters with a thickness of 0.5 mm. After press-coating, it is dried at 60°C to obtain a multi-layer wear-resistant flux-cored electrode with a diameter of 3.5 mm.

[0048] The application of the multi-layer wear-resistant flux-cored electrode as a cladding material in arc cladding to prepare a metal wear-resistant layer. The arc cladding adopts a MAG cladding process. Q235 steel is used as the substrate, and the surface of the substrate is treated by a sandblasting process to remove impurities on the surface of the substrate; then the MAG cladding process is used to clad the obtained multi-layer wear-resistant flux-cored electrode on the surface of the Q235 steel substrate; the cladding process parameters are: 80% Ar + 20% CO2 shielding gas, welding current of 200A, arc voltage of 28V, dry elongation of 15mm, and welding speed of 30cm / min.

[0049] Example 3

[0050] The multi-layer wear-resistant flux-cored electrode of this embodiment includes an inner core, a steel strip layer, a flux layer and a diamond micro-powder layer from the inside to the outside. The inner core is made of nickel-based solder powder; the flux layer is made of the following raw materials in mass percentage: CaF2 35%, TiO2 40%, MgO 20%, Al 5%. The particle size of the nickel-based solder powder is 50 μm; in the diamond micro-powder layer, the particle size of the diamond micro-powder is 25 μm.

[0051] The method for preparing the multi-layer wear-resistant flux-cored welding rod comprises the following steps:

[0052] (1) A nickel-based brazing filler metal powder is rolled from a steel strip having a thickness of 2 mm, and the steel strip layer is drawn at various stages to form a flux-cored welding wire having an inner core wrapped therein; wherein the filling rate of the nickel-based brazing filler metal powder is 46%; and the diameter of the flux-cored welding wire after drawing is 2.4 mm;

[0053] (2) The raw materials for the coating layer are mixed uniformly by a planetary mixer at a speed of 150 r / min for 1 h. Water glass (the mass ratio of sodium silicate to water in water glass is 1:10) is added to the uniformly mixed coating layer powder. The mass ratio of the coating layer powder to water glass is 5:1. After mixing for 2 h, a coating coating is obtained. In addition, water glass is added to diamond micropowder at a mass ratio of diamond micropowder to water glass of 10:1. The mixture is mixed for 2 h to obtain a uniform diamond coating.

[0054] (3) Using a pressure coating machine, the process parameters are: wire feeding speed: 5.3m / min, coating extrusion volume: 150cm 3 / min, the coating prepared in step (2) is coated on the surface of the flux-cored wire with a thickness of 1.1 mm, and then a layer of diamond coating is press-coated on the surface of the coating layer using the same process parameters with a thickness of 0.5 mm. After the press-coating, it is dried at 60°C to obtain a multi-layer wear-resistant flux-cored electrode with a diameter of 4.0 mm.

[0055] The above multi-layer wear-resistant flux-cored welding rod is used as a cladding material for manual cladding to prepare a metal wear-resistant layer. Q235 steel is used as the substrate, and the surface of the substrate is treated by sandblasting to remove impurities on the surface of the substrate; then the obtained multi-layer wear-resistant flux-cored welding rod is clad on the surface of the Q235 steel substrate by manual welding rod cladding process; the process parameters of manual cladding are: welding current is 130A, welding voltage is 25V, and welding speed is 13cm / min.

[0056] Comparative Example 1

[0057] The flux-cored electrode of this comparative example is a commercially available wear-resistant flux-cored electrode D778, which has a two-layer structure, a core made of tungsten carbide alloy powder, and a coating made of alkaline oxide (marble, fluorite).

[0058] The metal wear-resistant layer is prepared by surfacing welding using welding rod D778. The specific preparation process of the metal wear-resistant layer is referred to Example 3, the difference between the two is that different flux-cored welding rods are used, and the other parameters are the same.

[0059] Comparative Example 2

[0060] The flux-cored welding rod of this comparative example does not contain a coating layer in its structure, and the preparation of the coating layer is also omitted in the preparation process. The remaining processes are the same as those in Example 3.

[0061] The application of the flux-cored electrode in this comparative example as a cladding material for manual cladding to prepare a metal wear-resistant layer is basically the same as that in Example 3, the difference between the two is that different flux-cored electrodes are used, and the other parameters are the same.

[0062] Comparative Example 3

[0063] The flux-cored welding rod of this comparative example does not contain a diamond powder layer in its structure, and the preparation of the diamond powder layer is also omitted in the preparation process. The remaining processes are the same as those in Example 3.

[0064] The application of the flux-cored electrode in this comparative example as a cladding material for manual cladding to prepare a metal wear-resistant layer is basically the same as that in Example 3, the difference between the two is that different flux-cored electrodes are used, and the other parameters are the same.

[0065] Comparative Example 4

[0066] The structure of the flux-cored welding rod in this comparative example is the same as that of Example 3, except that the thickness of the diamond powder layer is different, which is set to 0.1 mm. The rest of the process is the same as that of Example 3.

[0067] The application of the flux-cored electrode in this comparative example as a cladding material for manual cladding to prepare a metal wear-resistant layer is basically the same as that in Example 3, the difference between the two is that different flux-cored electrodes are used, and the other parameters are the same.

[0068] Comparative Example 5

[0069] The flux-cored welding rod of this comparative example has a two-layer structure and a diameter of 4.0 mm. Diamond and nickel-based brazing filler metal powder are directly mixed together as the inner core during preparation, and then rolled with a steel strip. The rest of the process is the same as that of Example 3.

[0070] The application of the flux-cored electrode in this comparative example as a cladding material for manual cladding to prepare a metal wear-resistant layer is basically the same as that in Example 3, the difference between the two is that different flux-cored electrodes are used, and the other parameters are the same.

[0071] Test case performance test

[0072] With reference to the national standard GB / T 4340.1-2009 hardness test and GB / T 12444-2006 wear test method, the hardness and wear performance of the metal wear-resistant layers obtained in Examples 1 to 3 and Comparative Examples 1 to 5 were tested. Each sample was tested 5 times and the average value was calculated. The results are shown in Table 1.

[0073] Table 1 Performance test results of the metal wear-resistant layers obtained in Examples 1 to 3 and Comparative Examples 1 to 5

[0074]

[0075]

[0076] As can be seen from Table 1, the wear-resistant flux-cored welding rod of the multilayer structure of the present invention has better hardness and wear resistance than the flux-cored welding rods of Comparative Examples 1 to 5. Diamond is the hardest material. The present invention can significantly improve the wear resistance of the material by adding it to the composite welding rod in a multilayer structure design, which exceeds the commercially available wear-resistant flux-cored welding rod. At the same time, for multilayer composite welding rods, the coating layer is an indispensable arc stabilizing material in the cladding process. If it is missing, the harmful gas in the cladding layer will not be discharged in time, and the oxygen content will increase, resulting in a decrease in the overall hardness and wear resistance of the wear-resistant layer. In Comparative Example 5, diamond and nickel-based solder powder are directly mixed together to prepare an inner core. The other preparations are the same as the welding process. It is found that the degree of thermal damage of diamond is very different from that of the four-layer structure. This is because during the welding process, when the nickel-based solder powder is melted during the heating process, part of the diamond has been thermally damaged and loses its wear-resistant enhancement effect.

[0077] In summary, the multi-layer wear-resistant flux-cored welding rod provided by the present invention can form a wear-resistant layer with higher hardness, and can significantly improve the wear resistance of the substrate and extend the service life of the substrate. The present invention can effectively broaden the application scope of the flux-cored welding rod and has broad application prospects in the field of wear-resistant layer preparation and wear-resistant layer repair of forged parts.

Claims

1. A multi-layer wear-resistant flux-cored welding rod, characterized in that: From the inside to the outside, it includes the inner core, steel belt layer, coating layer and diamond powder layer; The inner core is composed of nickel-based solder powder; the mass percentage of the nickel-based solder powder is: B 2.75%-3.5%, Si 4%-5%, Cr 6%-8%, Fe 2.5%-3.5%, and the balance is Ni and unavoidable impurities; The coating layer is composed of the following raw materials in percentage by mass: CaF2 30%-40%, TiO2 35%-45%, MgO 15%-25%, Al 4%-6%; The nickel-based solder powder is rolled with a steel strip to form a flux-cored welding wire with an inner core wrapped by a steel strip layer; the ratio of the diameter of the flux-cored welding wire, the thickness of the coating layer, and the thickness of the diamond micropowder layer is (1.8-2.4): (1.0-1.1): (0.4-0.5).

2. The wear-resistant flux-cored welding rod with a multi-layer structure according to claim 1, characterized in that: The material of the steel strip layer is low-carbon cold-rolled steel strip.

3. The wear-resistant flux-cored welding rod with a multi-layer structure according to claim 1, characterized in that: The particle size of the nickel-based solder powder is 50-60 μm; and the particle size of the diamond powder in the diamond powder layer is 20-50 μm.

4. The wear-resistant flux-cored welding rod with a multi-layer structure according to claim 1, characterized in that: The diameter of the multi-layer wear-resistant flux-cored welding rod is 3.2-4.0 mm.

5. A method for preparing a multi-layer wear-resistant flux-cored welding electrode as claimed in claim 1, characterized in that: The following steps are involved: (1) Nickel-based brazing powder is rolled with steel strip to form a flux-cored welding wire with a steel strip layer wrapping the inner core; (2) using the raw material of the coating layer to prepare the coating coating; and using the diamond micro powder to prepare the diamond coating; (3) A coating is applied on the surface of the flux-cored welding wire to obtain a coating layer, and then a diamond coating is applied on the surface of the coating layer to obtain a diamond powder layer, thereby obtaining a wear-resistant flux-cored welding rod with a multi-layer structure.

6. The method for preparing a multi-layer wear-resistant flux-cored welding electrode according to claim 5, characterized in that: In step (1), the filling rate of the nickel-based solder powder in the steel strip is 45% to 50%.

7. The method for preparing a multi-layer wear-resistant flux-cored welding rod according to claim 5, characterized in that: The process conditions of the pressure coating are: wire feeding speed is 5-6 m / min, coating extrusion volume is 120-160 cm 3 / min.

8. The use of the multi-layer wear-resistant flux-cored welding rod according to any one of claims 1 to 4, characterized in that: It is used as a cladding material for surfacing welding to prepare metal wear-resistant layers.

9. The use of the multi-layer wear-resistant flux-cored welding rod according to claim 8, characterized in that: The surfacing welding is arc surfacing welding or manual surfacing welding; the process parameters of the arc surfacing welding are: welding current is 200~300A, arc voltage is 22~28V, dry extension is 12~18mm, and welding speed is 20~30cm / min; the process parameters of the manual surfacing welding are: welding current is 120~150A, welding voltage is 22~26V, and welding speed is 11~15cm / min.

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