Dispersion type wear-resistant tooth-shaped structure and manufacturing method thereof

Abstract

The invention provides a dispersion type wear-resistant tooth-shaped structure and a manufacturing method thereof. The method comprises the following steps: mixing and molding ceramic particles and a hot-melt binder to obtain a ceramic dispersion module; the ceramic dispersion module is placed in the position, corresponding to the wear-resistant part of the tooth-shaped structure, in the cavity of the tooth-shaped structure mold; molten steel is poured, so that the ceramic dispersion module is dispersed, the ceramic particles are dispersed and distributed in the solidified tooth-shaped structure, and the dispersion type wear-resistant tooth-shaped structure is obtained; the particle size of the ceramic particles is 0.8 mm to 1.2 mm; and the size of the gap of the ceramic dispersion module is 2mm-5mm. According to the preparation method disclosed by the invention, the novel tooth-shaped structure which comprises the isolating layer, the wear-resistant layer and the matrix layer and is integrally cast is prepared, so that on one hand, the problem that conventional ceramic particles cannot be uniformly distributed on the surface of the tooth-shaped structure due to low temperature and poor flowability of molten steel of high-manganese steel is solved; and the problem that the service life is seriously short due to the fact that a common tooth-shaped structure is not provided with a wear-resistant layer is solved.

Description

Technical Field

[0001] The invention relates to a dispersed wear-resistant tooth structure and a manufacturing method thereof, belonging to the technical field of mechanical equipment manufacturing. Background Art

[0002] Excavators use their buckets to squeeze and crush materials before loading. The front end of the bucket is equipped with teeth that come into direct contact with materials such as rock, gravel, and overburden during operation, constantly being squeezed by both the bucket and the material.

[0003] Traditional tooth structures are mostly cast from high-manganese steel, alloy steel, and other materials. These structures possess the characteristic of experiencing a sharp increase in hardness under intense impact conditions. However, this characteristic is lost in the absence of impact, resulting in the teeth's wear resistance being severely insufficient in non-impact conditions. Consequently, under the harsh conditions of the bucket and material being squeezed together, the teeth can quickly wear out and fail. Maintaining the excavator's operation requires downtime and tooth replacement, which not only impacts production efficiency but also significantly increases production costs.

[0004] The bucket is mainly composed of a boom 1, a bucket arm 2, a bucket 3 and a push shaft 4. Figure 1 As shown in the figure, the electric shovel relies on the lifting wire rope to lift the bucket, while the thrust shaft 4 pushes the bucket forward to cut into the working surface. The lifting and thrusting together drive the bucket. During this process, the teeth rush into the material, completing the loading task.

[0005] The working stress of the tooth structure is as follows Figure 2 As shown, the angle of the tooth structure during operation is as follows Figure 3 As shown in the figure, γ is the rake angle, δ is the cutting angle, β is the tooth structure angle, θ is the back angle, F is the total excavation resistance, F1 is the vertical component along the normal of the trajectory, and F2 is the tangential component along the motion trajectory between the tooth structures.

[0006] It is not difficult to see from the tooth structure and working mode diagram that when the tooth structure is working:

[0007] 1. The tip of the tooth structure is subject to the greatest impact and pressure. Therefore, it is necessary to improve the life of the tooth structure under impact conditions.

[0008] 2. The material mainly passes through the front surface of the tooth structure, and the material has little impact on the tooth structure. The high manganese steel substrate tooth structure will not show the characteristics of work hardening when there is no impact working condition, so the failure is mainly due to wear. Therefore, it is necessary to improve the wear resistance of the tooth structure under normal friction conditions.

[0009] 3. During operation, the lower surface of the tooth structure slides along the shape of the working surface, and the rear surface of the tooth structure often scrapes against the working surface, but does not form a severe impact. The high manganese steel base tooth structure will not show the characteristics of work hardening when there is no impact working condition. However, the lower surface hardness of the tooth structure is low and the wear resistance is insufficient. Severe wear will not only cause grooves, but also cause the cross-sectional shape of the tooth structure to deteriorate. At the same time, as the wear increases, the cross-section of the tooth structure becomes smaller, which will cause the tip of the tooth structure to break. Not only will the service life of the tooth structure be affected, but the broken tip of the tooth structure will also cause huge damage to subsequent equipment after mixing with ore, causing serious economic losses and safety hazards to continuous production.

[0010] At present, there are three main methods to improve the wear resistance of tooth structures under non-impact conditions:

[0011] 1. High-hardness, high-strength, wear-resistant alloy steels with certain nickel, chromium, molybdenum, titanium and other alloy elements are used and a special heat treatment process is used to solve the contradiction between high hardness and brittleness. However, this method is expensive and the effect is not very stable, especially under high impact conditions and high hardness geological conditions. The life of the tooth structure is extremely short.

[0012] 2. A wear-resistant layer of cemented carbide is welded on the tip of the tooth structure. However, during use, especially under impact conditions, the wear-resistant layer peels off severely, resulting in extremely poor performance.

[0013] 3. Carbide tooth rods are embedded in the front and surface of the tooth structure. However, since the base material of the tooth structure is not wear-resistant, the base material will wear rapidly during use, which will soon cause the alloy rods to become loose, exposed, and even fall off, failing to achieve the expected effect.

[0014] Therefore, how to improve the wear resistance of the wear-resistant tooth structure and extend its service life is a technical problem that needs to be solved urgently in this field. Summary of the Invention

[0015] In order to solve the above technical problems, the purpose of the present invention is to provide a dispersed wear-resistant tooth structure and a manufacturing method thereof, in which ceramic particles are dispersed, which can significantly improve the wear resistance of the tooth structure.

[0016] To achieve the above object, the present invention first provides a method for manufacturing a dispersed wear-resistant tooth structure, which comprises the following steps:

[0017] Mixing ceramic particles with a hot-melt binder to form a ceramic dispersion module;

[0018] Placing the ceramic dispersion module in the cavity of the tooth structure mold at a position corresponding to the wear-resistant portion of the tooth structure;

[0019] pouring molten steel to disperse the ceramic dispersion module and disperse the ceramic particles in the solidified tooth structure to obtain the dispersed wear-resistant tooth structure;

[0020] Wherein, the particle size of the ceramic particles is 0.8mm-1.2mm;

[0021] The gap size of the ceramic dispersion module is 2mm-5mm.

[0022] In the above-mentioned production method, preferably, the heat-meltable adhesive comprises PVA and / or water glass. PVA can be prepared into an aqueous solution of appropriate concentration for use, and the concentration is generally controlled to be 3-30wt%, preferably 8wt%. By using PVA, water glass, etc. as adhesives and controlling their concentration, and simultaneously using ceramic particles of appropriate particle size, the ceramic particles can be stably bonded together to form a ceramic dispersion module of the desired shape. When the concentration of the heat-meltable adhesive is too high (over 30wt%), the dispersion effect is poor, and lumps will appear. When the concentration is too low (less than 3wt%), the bonding effect is relatively poor, and the ceramic particles cannot maintain a dispersed state, but are irregularly distributed, and ultimately cannot be evenly distributed in the tooth structure. After pouring molten steel, the molten steel can enter the gap inside the ceramic dispersion module, and the PVA and water glass can gradually volatilize under the high temperature of the molten steel, thereby causing the ceramic dispersion module to gradually disintegrate and disperse, and the ceramic particles enter the molten steel system and are stably suspended. Finally, after the molten steel solidifies, the ceramic particles can be dispersed and distributed in the tooth structure. Due to the use of PVA and water glass, the ceramic dispersion module of the present invention will not directly collapse under the action of high-temperature molten steel, but will disintegrate and disperse in an orderly manner, which ensures the stable suspension of ceramic particles in the molten steel and the ultimate uniform dispersion distribution in the tooth structure.

[0023] In the above-mentioned manufacturing method, the ceramic dispersion module is placed in the mold cavity of the tooth structure mold at a position corresponding to the wear-resistant part of the tooth structure. The wear-resistant part of the tooth structure here refers to the position in the tooth structure where the wear resistance needs to be improved, such as the lower surface of the tooth structure, etc., which can be selected and controlled according to actual needs.

[0024] In the above production method, preferably, the particle size of the ceramic particles is 1 mm.

[0025] In the above manufacturing method, preferably, the gap size d of the ceramic dispersion module (such as Figure 4 The gap size of the ceramic dispersion module is the distance between the ceramic particles dispersed in the wear-resistant layer after the tooth structure is solidified and formed.

[0026] In the above manufacturing method, preferably, the material of the ceramic particles is alumina (ZTA) and / or zirconia (ATZ).

[0027] In the above-mentioned production method, preferably, the mass ratio of the ceramic particles to the hot-melt adhesive is 9:1-10:1.

[0028] In the above manufacturing method, preferably, the thickness of the ceramic dispersion module is less than 20% of the cross-sectional thickness of the tooth structure. For specific products, the size of the ceramic dispersion module can be determined according to needs. Generally, the thickness does not exceed 20% of the cross-sectional thickness of the tooth structure. Other dimensions such as the area of ​​the ceramic dispersion module can be determined according to product needs. The cross-sectional thickness of the tooth structure refers to: the distance between the front surface of the tooth structure and the rear surface of the tooth structure (such as Figure 2 The specific shape and other dimensions of the ceramic dispersion module can be adaptively controlled based on the shape and dimensions of the tooth structure, as long as they can meet the needs of the tooth structure. The angle at which the ceramic dispersion module is added can also be controlled based on the shape of the tooth structure.

[0029] In the above production method, preferably, the temperature of pouring molten steel is 1420℃-1450℃.

[0030] In the above-mentioned manufacturing method, the molten steel used can be steel commonly used in preparing tooth structures, such as high manganese steel, alloy steel, etc.

[0031] In the field of tooth structure, high manganese steel is usually used as tooth structure matrix material, with low cost, high life when impact and material blasting are poor, many advantages such as raw material acquisition and preparation are simple, but, need to solve when there is no impact working condition, the tooth structure that the high manganese steel substrate tooth structure cannot show the characteristic of work hardening and causes is not wear-resistant problem, prior art is generally by increasing the mode of protruding reinforcement (such as ceramic reinforcement, cemented carbide reinforcement) on the tooth structure surface to be solved, but there is a certain bonding interface between this reinforcement and the tooth structure matrix, because the expansion coefficient of the material of the two generally has a large difference, therefore in use, there is easily the problem that reinforcement falls off, thereby causing failure. The present invention, by means of the high strength, high hardness and high wear resistance of ceramic particles, uses it as reinforcement to prepare the novel tooth structure of ceramic particle reinforced metal matrix composite material, so that it has the advantages such as good plasticity and impact toughness, easy forming of matrix metal. However, the present invention has found that: due to the complex shape of the tooth structure, ceramic particles cannot be fixed in a specific position in the casting mold under normal circumstances. At the same time, when the molten steel enters the mold cavity, it washes the particles and cannot be evenly distributed on the surface of the tooth structure to form a wear-resistant layer. To this end, the manufacturing method provided by the present invention adopts a hot-melt adhesive and controls its concentration, and is combined with ceramic particles of appropriate particle size, so that the ceramic particles can be bonded into a whole, that is, a ceramic dispersion module. The ceramic dispersion module is suspended inside the tooth structure mold before casting. When the molten steel is filled in, the high temperature of the molten steel can dissolve and volatilize the hot-melt adhesive, avoiding it from remaining inside the tooth structure and affecting the performance of the tooth structure. At the same time, after the hot-melt adhesive dissolves and volatilizes, the ceramic dispersion module will also disperse (or decompose, collapse, and spread like an effervescent tablet), so that the ceramic particles enter the molten steel system and suspend. Finally, as the temperature of the molten steel decreases, it solidifies and disperses between the outer metal (isolation layer) and the core metal (matrix layer), thereby forming a wear-resistant layer and improving wear resistance.

[0032] At the same time, the present invention further discovered that the gaps between the ceramic particles of the ceramic dispersion module also significantly affect the distribution of ceramic particles in the tooth structure. Specifically, when the gaps between the ceramic particles are large, the ceramic dispersion module is easily disintegrated by the high-temperature molten steel. After the tooth structure solidifies, the ceramic particles in the wear-resistant layer are easily peeled off, and the wear-resistant effect is significantly reduced. When the gaps are small, when the molten steel temperature is relatively low and the fluidity is poor, the molten steel will not be able to smoothly merge with the ceramic particles to achieve uniform distribution. This problem can be avoided by controlling the distance between the ceramic particles (i.e., the gap size of the ceramic dispersion module) to 2mm-5mm.

[0033] In the above-mentioned manufacturing method, the ceramic dispersion module must be suspended inside the tooth structure, otherwise it is easy to produce defects such as pores, slag inclusions, and cracks during the composite process with the base metal, and ultimately the polymer cannot be evenly dispersed to form a wear-resistant layer with uniform structure; due to the extremely large buoyancy and impact force of the molten steel, if the ceramic dispersion module collapses prematurely, the distribution of the ceramic particles will not meet the dispersion requirements or will be piled up together, which will cause the structural strength of the tooth structure at this point to be too large, and it will quickly break when subjected to force. The ceramic dispersion module provided by the present invention can withstand the impact of the molten steel during the pouring process, and will not collapse directly. Instead, it will gradually disintegrate and disperse after the molten steel is poured, thereby ensuring that during the pouring and cooling process of the molten steel, the ceramic dispersion module can be stably suspended inside the tooth structure (or inside the mold cavity), so that the ceramic particles can be evenly dispersed and distributed in the cooled tooth structure to form a wear-resistant layer. There will be a certain gap between the ceramic dispersion module and the inside of the mold. During the cooling process of the molten steel, the molten steel will form an isolation layer in this gap between the outside of the wear-resistant layer dispersed with ceramic particles and the mold. When subjected to external wear during operation, the isolation layer can function simultaneously with the wear-resistant layer. As the wear time increases, the isolation layer gradually wears away, and the wear-resistant layer is exposed on the surface of the tooth structure, allowing excavation work to be carried out independently, thereby extending the working life of the tooth structure.

[0034] The present invention also provides a dispersed wear-resistant tooth structure, which is obtained by the above-mentioned manufacturing method.

[0035] According to a specific embodiment of the present invention, preferably, the dispersed wear-resistant tooth structure is composed of a base layer, a wear-resistant layer, and an isolation layer, wherein ceramic particles are dispersed in the wear-resistant layer, and the coverage density of the ceramic particles per unit area of ​​the wear-resistant layer is 15%-25%. The ceramic particles are dispersed in the wear-resistant layer. Due to their small size, they can form a good bond with the tooth structure base, and are indistinguishable from the appearance (i.e., the tooth structure prepared by the present invention does not have reinforcements protruding from the surface, and the ceramic particles are distributed inside the tooth structure). Unlike reinforcements such as embedded carbide tooth rods, there is no obvious visible interface with the tooth structure base. Moreover, because the ceramic particles are dispersed, the wear-resistant layer formed does not have stress concentration, thus providing good wear resistance and mechanical strength. The coverage density of the ceramic particles per unit area of ​​the wear-resistant layer can be calculated by calculating the coverage area of ​​the ceramic particles per unit area of ​​the wear-resistant layer cross-section (the surface parallel to the outer surface of the tooth structure). The proportion of this coverage area is the coverage density.

[0036] According to a specific embodiment of the present invention, preferably, the thickness of the wear-resistant layer is 15 mm to 25 mm. For specific products, the thickness of the wear-resistant layer can be controlled as needed.

[0037] According to a specific embodiment of the present invention, preferably, the thickness of the isolation layer is 15 mm to 25 mm.

[0038] The present invention controls the size of the ceramic dispersion module (internal particle gap) and combines a preparation method of adding an isolation layer as a transition layer on the surface of the ceramic dispersion module to obtain a new tooth structure including an isolation layer, a wear-resistant layer, and a base layer cast in one piece. On the one hand, it solves the problem that high manganese steel liquid steel cannot evenly distribute conventional ceramic particles on the surface of the tooth structure due to its low temperature and poor fluidity. On the other hand, it solves the problem that the ordinary tooth structure has a seriously insufficient life due to the lack of a wear-resistant layer. It becomes the first choice to replace the traditional single high manganese steel or other wear-resistant alloy tooth structure, and is a cutting-edge direction in the field of wear-resistant parts. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 This is a schematic diagram of the electric shovel working device.

[0040] Figure 2 Schematic diagram of the force on the tooth structure in working condition.

[0041] Figure 3 Schematic diagram of the angle of the tooth structure in working state.

[0042] Figure 4 This is a schematic structural diagram of the ceramic dispersion module provided in Example 1.

[0043] Figure 5 This is a cross-sectional schematic diagram of the dispersed wear-resistant tooth structure provided in Example 2.

[0044] Figure 6 and Figure 7 This is a schematic structural diagram of the dispersed wear-resistant tooth structure provided in Example 2.

[0045] Description of main figures:

[0046] 1. Boom; 2. Arm; 3. Bucket; 4. Push shaft; 5. Ceramic particles; 6. Base; 7. Wear-resistant layer; 8. Isolation layer. DETAILED DESCRIPTION

[0047] In order to have a clearer understanding of the technical features, objectives and beneficial effects of the present invention, the technical solution of the present invention is now described in detail below, but it should not be understood as limiting the scope of implementation of the present invention.

[0048] Experimental example

[0049] This experimental example provides a method for manufacturing a dispersed wear-resistant tooth structure based on different parameters for comparison.

[0050] The above-mentioned production method comprises the following steps:

[0051] The ceramic particles were mixed with a PVA aqueous solution (8 wt%) in a mass ratio of 10:1, and the mixture was placed in a mold for curing to obtain a ceramic dispersion module;

[0052] Placing the ceramic dispersion module in the cavity of the tooth structure mold at a position corresponding to the wear-resistant part of the tooth structure;

[0053] Pouring molten steel to disperse the ceramic dispersion modules and disperse the ceramic particles in the solidified tooth structure to obtain a dispersed wear-resistant tooth structure;

[0054] Among them, the particle size of ceramic particles and the gap size of ceramic dispersion module are shown in Table 1;

[0055] The structure of the ceramic dispersion module is as follows Figure 4 As shown, the body comprises ceramic particles 5, with gaps between the ceramic particles 5, which are filled with PVA to bond the ceramic particles 5 into a whole. It should be noted that: Figure 4 This is only a schematic diagram, and the size ratio does not represent the actual size ratio.

[0056] The material of the ceramic particles 5 is alumina;

[0057] The thickness of the ceramic dispersion module is 20% of the cross-sectional thickness of the tooth structure;

[0058] The material of molten steel is ZGMn13Mo, and the pouring temperature of molten steel is 1420℃-1450℃;

[0059] The cross-sectional structure of the solidified tooth structure is as follows Figure 5 As shown, it consists of a base 6, a wear-resistant layer 7, and an isolation layer 8, wherein the wear-resistant layer 7 has a thickness of 20 mm and a ceramic particle coverage density per unit area of ​​the wear-resistant layer 7 of 20%; the isolation layer 8 is located on the outermost side and has a thickness of 20 mm.

[0060] The structural diagram of the dispersed wear-resistant tooth structure of this embodiment is as follows Figure 6 and Figure 7 As shown. Figure 6 、 Figure 7 It can be seen that the front end portion of the base body 6 of the dispersed wear-resistant tooth structure has a wear-resistant layer 7 , and the outside of the base body 6 is covered with an isolation layer 8 .

[0061] The service life test of the prepared dispersed wear-resistant tooth structure was carried out in the following manner: the prepared tooth structure was installed on a mechanical excavator for installation test. The machine model was a large mechanical excavator. The actual test was to perform sandy rock and soil stripping work. The test time was summer.

[0062] The test results are shown in Table 2; the service life of the unreinforced tooth structure is generally 100-120 hours.

[0063] Table 1

[0064]

[0065] Table 2

[0066]

[0067]

[0068] According to the above experimental results, it can be seen that in the tooth structures prepared by groups I-IV, the wear-resistant layer with dispersed ceramic particles can greatly improve the wear resistance of the tooth structure, thereby significantly extending the service life of the tooth structure; among them, the technical effect of group III is the best.

[0069] The present invention adopts a special method to manufacture the tooth structure into a local composite manner containing an isolation layer, a wear-resistant layer, and a matrix. With the help of the above structure and in combination with dispersed ceramic particles, the wear resistance of the tooth structure can be improved, and its overall toughness can be ensured. It can greatly extend the service life of the tooth structure, solve the problems of heavy wear and strong impact, extend the service life, and save costs.

Claims

1. A method for manufacturing a dispersed wear-resistant tooth structure, comprising the following steps: Mixing ceramic particles with a hot-melt binder to form a ceramic dispersion module; Placing the ceramic dispersion module in the cavity of the tooth structure mold at a position corresponding to the wear-resistant portion of the tooth structure; pouring molten steel to disperse the ceramic dispersion module and disperse the ceramic particles in the solidified tooth structure to obtain the dispersed wear-resistant tooth structure; Wherein, the particle size of the ceramic particles is 0.8mm-1.2mm, preferably 1mm; The gap size of the ceramic dispersion module is 2mm-5mm, preferably 4mm-5mm.

2. The production method according to claim 1, wherein The hot-melt adhesive includes PVA and / or water glass.

3. The production method according to claim 1, wherein The ceramic particles are made of aluminum oxide and / or zirconium oxide.

4. The production method according to claim 1, wherein The mass ratio of the ceramic particles to the hot-melt adhesive is 9:1-10:

1.

5. The production method according to claim 1, wherein: The thickness of the ceramic dispersion module is less than 20% of the thickness of the tooth-shaped structure cross section.

6. The production method according to claim 1, wherein: The temperature of pouring molten steel is 1420℃-1450℃.

7. A dispersed wear-resistant tooth structure obtained by the manufacturing method according to any one of claims 1 to 6.

8. The dispersed wear-resistant tooth structure according to claim 7, wherein: The dispersed wear-resistant tooth structure consists of a base layer, a wear-resistant layer and an isolation layer, wherein ceramic particles are dispersed in the wear-resistant layer, and the coverage density of the ceramic particles per unit area of ​​the wear-resistant layer is 15%-25%.

9. The dispersed wear-resistant tooth structure according to claim 8, wherein: The thickness of the wear-resistant layer is 15mm-25mm.

10. The dispersed wear-resistant tooth structure according to claim 8, wherein: The thickness of the isolation layer is 15mm-25mm.

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