Surface strengthening technology for chain nest of mining chain wheel

Abstract

The invention discloses a mining chain wheel chain nest surface strengthening technology, and relates to the technical field of additive manufacturing, in particular to a method for improving the surface abrasion resistance of a chain wheel chain nest through robot automatic laser cladding. Comprising the following steps: forming a chain wheel body wear-resistant phase, forming a cladding multi-layer wear-resistant phase, and planning the travel path track of a laser by utilizing programming software. The cladding layer adopts three-layer laser cladding including a base layer, a transition layer and a surface covering layer, each layer of surfacing track adopts a zigzag path, in order to make the cladding track more fit the chain nest curved surface, off-line programming software is utilized, and a programmed track program is copied to a laser cladding robot, so that the surface of the chain nest curved surface is subjected to laser cladding; program correction is carried out through the initial position marked on the chain nest so as to ensure that the track is consistent with the real object. Through linkage of the positioner and the robot, the molten pool forming position is always in the horizontal position, and the situation that due to gravity, the molten pool flows, and the uniformity of the thickness of a cladding layer is affected is avoided.

Description

Technical Field

[0001] The invention relates to a technology for strengthening the surface of a chain socket of a sprocket of a mining scraper conveyor to improve the wear resistance of the sprocket, and relates to the technical field of additive manufacturing. Background Art

[0002] The mining sprocket is the only power input component of the scraper conveyor. The power transmission is achieved through the precise meshing of the chain nest and the chain. The meshing tooth surface chain nest position is severely worn in the meshing transmission with long-term heavy load, impact and lack of lubrication. Therefore, the main failure form of the mining sprocket assembly is chain nest wear. At present, the research on improving the wear resistance of the sprocket mainly focuses on the following two aspects: one is to increase the sprocket material grade by increasing the alloy element content of the sprocket body to improve the surface hardenability and hardenability of the chain nest; the other is to cover the surface of the chain nest with a wear-resistant layer. Due to the obvious increase in material cost and processing cost caused by the increase in material grade, there have been many studies on covering the surface of the chain nest with wear-resistant materials in recent years. The surfacing layer formed by the surfacing method of the chain nest surface is poorly combined with the chain nest matrix and is easy to fall off in blocks under heavy load impact. In addition, the heat input of the surfacing wear-resistant layer will cause the annealing of the chain nest hardened layer. Therefore, the sprocket life of the surfacing wear-resistant layer is not significantly improved, especially when used in rings with harsh conditions in underground working. Summary of the invention

[0003] The purpose of the present invention is to overcome the shortcomings of large heat input of surface cladding on the chain socket of a mining sprocket, poor bonding strength between the cladding layer and the substrate, and poor wear resistance, and to provide a laser cladding technology for the chain socket of a mining sprocket, which can form multiple strengthening phases at the chain socket position and significantly improve the wear resistance of the chain socket.

[0004] To achieve the above purpose, the sprocket body base material is made of electroslag remelting forging blank, which is composed of the following components and percentages: carbon 0.38-0.50%, silicon 0.20-0.40%, manganese 0.50-0.80%, chromium 1.50-2.20%, nickel 1.60-1.90%, molybdenum 0.30-0.800%, vanadium 0.10-0.30%, phosphorus ≤0.025%, sulfur ≤0.015%, and the rest is iron. The surface of the sprocket chain nest processed by this material is heated to 900℃ and then quenched in water medium, and tempered at 230℃ for 5h. The surface hardness is HRC53-55, and the depth of the hardened layer is>15mm.

[0005] In the embodiment of the present invention, the laser cladding at the sprocket chain nest position is divided into three layers, including a base layer, a transition layer and a cover layer. The heat input of laser additive is small, and the annealing depth of the chain nest matrix hardened layer is less than 1mm. The hardened layer can still have a considerable service life after the cladding layer is worn.

[0006] In the embodiment of the present invention, the thickness of the laser cladding base layer is 1mm, and the hardness should not be too high, between HRC45 and HRC50, which can ensure good bonding with the substrate and provide sufficient support for the transition layer and the cover layer under heavy load to avoid the wear-resistant layer from crushing and failure. The base layer is made of Ni35-20% WC nickel-based tungsten carbide material, the laser power is 1500 W, the powder feeding amount is 2.5 g / s, and the cladding speed is 5 mm / s.

[0007] In the embodiment of the present invention, the thickness of the laser cladding transition layer is 1 mm, HRC55-60, Ni45-40%WC nickel-based tungsten carbide material is used, the laser power is 1500 W, the powder feeding amount is 2.0 g / s, and the cladding speed is 4 mm / s.

[0008] In the embodiment of the present invention, the laser melting covering layer thickness is 1 mm, HRC>58, Ni45-60%WC nickel-based tungsten carbide material is used, the laser power is 1500W, the powder feeding amount is 1.5 g / s, and the cladding speed is 3 mm / s.

[0009] In the embodiment of the present invention, the laser cladding trajectory is input into the robot using off-line programming, and the automatic cladding process is linked by the positioner and the robot so that the molten pool formation position is always in a horizontal position.

[0010] The beneficial effect of the mining sprocket provided by the present invention is that the chain nest base hardening layer plus the laser cladding layer can make the chain nest effective wear-resistant layer thickness exceed 20mm, the chain nest surface hardness is greater than HRC58, and the service life of the sprocket can be significantly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0012] Figure 1 Schematic diagram of chain nest cladding position; Figure 2 Schematic diagram of cladding trajectory; Wherein: 1. sprocket body; 2. chain nest clad with wear-resistant layer. DETAILED DESCRIPTION

[0013] The present invention is described clearly below in conjunction with the drawings and specific embodiments in the embodiments of the present invention. The description herein is only used to explain the present invention, but is not intended to limit the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work, any modifications, equivalent substitutions, improvements, etc., should be included in the protection scope of the present invention.

[0014] The purpose of the present invention is to provide a sprocket chain nest surface strengthening technology to solve the problem of sprocket wear resistance, by increasing the chain nest surface quenching hardness and quenching layer depth and chain nest surface coating wear-resistant material to achieve the purpose of improving the wear resistance of the sprocket.

[0015] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0016] like Figure 1 As shown, a layer of wear-resistant material 2 is coated on the surface of the chain pocket of the sprocket body 1 by laser cladding technology.

[0017] In order to ensure that the sprocket body has sufficient service life, the chain nest position is heat-treated and strengthened before the wear-resistant material is clad. In order to make the chain nest have sufficient quenching hardness and hardening depth, the sprocket body base material is made of electroslag re-melted forging blank, which is composed of the following components and percentages: carbon 0.38-0.50%, silicon 0.20-0.40%, manganese 0.50-0.80%, chromium 1.50-2.20%, nickel 1.60-1.90%, molybdenum 0.30-0.800%, vanadium 0.10-0.30%, phosphorus ≤0.025%, sulfur ≤0.015%, and the rest is iron. The surface of the sprocket chain nest position processed by this material is heated to 900℃ and then quenched in water medium, and tempered at 230℃ for 5h. The surface hardness is HRC53-55, and the depth of the hardened layer is greater than 15mm.

[0018] To ensure Figure 1 The wear-resistant layer 2 shown has good adhesion. The wear-resistant layer 2 is clad in three layers: base layer, transition layer, and cover layer. The thickness of each layer is 1 mm. The cladding tracks of the three layers are as follows Figure 2 The zigzag shape shown in the figure, the cladding trajectory is input into the robot after offline programming, and each layer of cladding is Figure 2 The reference point calibration shown in the figure, the automatic cladding process ensures that the molten pool formation position is always in a horizontal position through the linkage of the positioner and the robot.

[0019] The base layer HRC45-50 can ensure good bonding with the substrate and provide sufficient support for the transition layer and the cover layer under heavy load to avoid the collapse and failure of the wear-resistant layer. Ni35-20% WC nickel-based tungsten carbide material is used, the laser power is 1500W, the powder feeding amount is 2.5 g / s, and the cladding speed is 5 mm / s. Ni45-40% WC nickel-based tungsten carbide material, the laser power is 1500W, the powder feeding amount is 2.0 g / s, and the cladding speed is 4 mm / s. Ni45-60% WC nickel-based tungsten carbide material, the laser power is 1500W, the powder feeding amount is 1.5 g / s, and the cladding speed is 3 mm / s.

[0020] It should be noted that it is obvious to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and that the present invention can be implemented in other specific forms without departing from the basic features of the present invention. Therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention, and any reference numerals in the claims should not be regarded as limiting the claims involved.

[0021] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only used to help understand the method and core ideas of the present invention. At the same time, for those skilled in the art, according to the ideas of the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A method for strengthening the surface of a chain socket of a mining sprocket, characterized in that: Heat treatment strengthening of the chain socket position of the sprocket body, laser cladding trajectory planning, and formation of multi-layer laser cladding wear-resistant layer.

2. According to claim 1, a method for strengthening the surface of the chain socket of a mining sprocket is characterized in that The sprocket body mother material involved is made of electroslag remelting forging blank, and the chain nest position of the sprocket body is hardened by flame heating followed by water cooling. To ensure the strength and wear resistance of the sprocket body, the surface quenching hardness of the chain nest before laser cladding is HRC53~55, and the hardening depth is greater than 15mm.

3. The surface strengthening method of the chain socket position of a mining sprocket according to claim 1 is characterized in that The laser additive manufacturing at the chain nest position of the mining sprocket involved is divided into three layers: base layer, transition layer and cover layer, and all three layers are made of nickel-based tungsten carbide material.

4. The surface strengthening method of the chain socket position of a mining sprocket according to claim 3 is characterized in that The base layer involved must ensure sufficient bonding strength with the quenched chain nest surface to ensure that the cladding layer will not fail due to normal wear during use and avoid peeling of the cladding layer. The base layer thickness is 1 mm, using Ni35-20% WC nickel-based tungsten carbide material, laser power 1500 W, powder feed 2.5 g / s, and cladding speed 5 mm / s.

5. The surface strengthening method of the chain socket position of a mining sprocket according to claim 3 is characterized in that The transition layer involved has a thickness of 1 mm and has sufficient hardness and wear resistance. It uses Ni45-40% WC nickel-based tungsten carbide material, a laser power of 1500 W, a powder feed rate of 2.0 g / s, and a cladding speed of 4 mm / s.

6. The surface strengthening method of the chain socket position of a mining sprocket according to claim 3 is characterized in that The cover layer involved has a thickness of 1 mm and has sufficient hardness HRC ≥ 58. Microcracks on the surface are allowed. Ni45-60% WC nickel-based tungsten carbide material is used. The laser power is 1500 W, the powder feed rate is 1.5 g / s, and the cladding speed is 3 mm / s.

7. The surface strengthening method of the chain socket position of a mining sprocket according to claim 1 is characterized in that The robot automatic cladding involved ensures that the molten pool formation position is always in a horizontal position through the linkage between the positioner and the robot.

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