Self-repairing mining vertical chain connecting ring and manufacturing method thereof

Abstract

The invention belongs to the technical field of coal mine machinery, and particularly relates to a self-repairing mining vertical chain connecting ring and a manufacturing method thereof.The chain connecting ring takes 23MnNiMoCr54 alloy steel as a base material and is made of a steel billet added with self-repairing material components; the self-repairing material comprises nano-particles, shape memory alloy particles and a catalyst. According to the mining vertical chain connecting ring, the self-repairing material is added on the original basis, so that the chain connecting ring automatically repairs surface and internal damage under the complex working condition environment of a mine, the service life of the chain connecting ring is effectively prolonged, and compared with a traditional chain connecting ring, the service life can be prolonged by 30%-50%. The 23MnNiMoCr54 alloy steel is used as a base material, self-repairing material components and a special preparation process are combined, the original excellent mechanical properties such as high strength and high toughness of the chain connecting ring are guaranteed, meanwhile, the chain connecting ring is endowed with the self-repairing characteristic, and good comprehensive performance is achieved.

Description

Technical Field

[0001] This invention belongs to the field of coal mine machinery technology, specifically relating to a self-healing vertical connecting chain ring for mining and its manufacturing method. Background Technology

[0002] In mining operations, mining chains are key components of equipment such as scraper conveyors and coal planers. The connecting links, as crucial parts connecting the chains, directly impact the safety and efficiency of the entire conveying system. Currently, commonly used mining connecting links are mostly made of alloy steel, such as 23MnNiMoCr54 alloy steel. While possessing certain strength and wear resistance, under long-term exposure to alternating loads, impacts, and harsh environments underground, the surface and interior of the connecting links are prone to cracks and wear. Once this damage accumulates to a certain extent, it can lead to chain breakage, causing equipment failure or even safety accidents. Existing connecting links lack the ability to automatically repair damage, requiring periodic inspection and replacement to maintain system operation. This not only increases maintenance costs and downtime but also carries the risk of accidents due to oversights in inspection. Therefore, developing a mining connecting link capable of automatically repairing damage is of significant practical importance. Summary of the Invention

[0003] To address the technical problems existing in current mining chain links, this invention provides a self-healing vertical mining chain link and its manufacturing method. The entire repair process is autonomously triggered by damage (cracks, stress) generated during the operation of the chain link and the operating environment (frictional heat, underground moisture), requiring no external energy intervention or manual operation.

[0004] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: A self-healing vertical connecting link for mining, the connecting link is made of 23MnNiMoCr54 alloy steel as the base material and is made of steel billet with added self-healing material components; the self-healing material components include nanoparticles, shape memory alloy particles and catalysts. The nanoparticles are used to fill micro-cracks and wear pits on the surface of the chain links, and account for 5%-8% of the total weight of 23MnNiMoCr54 alloy steel; The shape memory alloy particles are used to fill cracks inside the connecting links and account for 3%-5% of the total weight of 23MnNiMoCr54 alloy steel; The catalyst is used to promote the self-healing reaction and accounts for 1%-2% of the total weight of 23MnNiMoCr54 alloy steel.

[0005] The nanoparticles are alumina nanoparticles, which have high hardness and thermal stability; the shape memory alloy particles are nickel-titanium shape memory alloy particles, which have wear resistance and corrosion resistance, and the phase transformation temperature Af point is adjusted to 45℃-60℃ to adapt to the temperature rise of downhole equipment operation; the catalyst is a metal salt catalyst, which can release ions to catalyze the repair reaction in a humid environment.

[0006] When used in underground mines, the connecting ring forms a three-level synergistic self-healing mechanism: when slight wear occurs on the surface, the exposed alumina nanoparticles provide excellent wear resistance; simultaneously, the local temperature rise caused by wear triggers the omagnetic phase transformation of adjacent shape memory alloy fibers, resulting in micro-shrinkage, compensating for the wear, and maintaining dimensional stability; when microcracks occur, the interaction of ambient moisture and catalysts causes the nanoparticles to migrate to the damaged area and solidify; when macro-cracks or local stress concentrations occur, the frictional temperature rise and mechanical load trigger the shape memory alloy phase transformation, generating compressive strain, thereby achieving automatic repair of surface and internal damage.

[0007] A method for manufacturing a self-healing vertical connecting link for mining includes the following steps: S1. Raw material prefabrication, forging and heat treatment: 23MnNiMoCr54 alloy steel and self-healing material components are made into uniform steel billets using powder metallurgy process, the steel billets are forged, and then the forgings are normalized. S2. Machining and heat treatment of the connecting parts: Machining is performed on the connecting parts of the forgings after normalizing, and then the machined parts are quenched and tempered. S3. Surface treatment: The heat-treated parts are shot-blasted and then coated with anti-corrosion paint.

[0008] The specific process of S1 includes: S11. Raw material prefabrication: Alumina nanoparticles are uniformly embedded on the surface of 23MnNiMoCr54 alloy steel powder using high-energy ball milling technology to form a core-shell structured composite powder. The composite powder is then three-dimensionally mechanically mixed with shape memory alloy particles and a catalyst to prepare a uniform steel billet.

[0009] S12. Forging process: The S11 steel billet is sawn to size and then uniformly heated to the forging temperature using a special mold to avoid excessive internal and external temperature differences that could cause thermal stress. The initial forging temperature is 1150℃-1200℃, and the final forging temperature is 850℃-900℃. The steel billet is plastically deformed to form the basic shape of a connecting link. S13. Normalizing process: Heat the forging to 850℃-930℃ at a heating rate of 2℃ / min-5℃ / min, hold for 1-3 hours and then cool in air to refine the grains and homogenize the microstructure.

[0010] In step S12, while forming the basic shape of the connecting ring through plastic deformation, grain refinement and internal defect compaction are achieved.

[0011] The specific process of S2 includes: S21. Machining process of connecting parts: The reference surface, tenon and mortise of the forging are machined with cutting tools. The machined parts are then assembled in pairs and the pin holes are machined. S22, Heat treatment process: Quenching: Heat the processed parts to 850℃-900℃ at a heating rate of 2℃ / min-5℃ / min, hold for 1-3 hours, and then water cool to room temperature; Tempering: Heat the quenched parts to 450℃-550℃ at a heating rate of 2℃ / min-5℃ / min, hold for 2-4 hours, and then air cool to room temperature.

[0012] The specific process of S3 is as follows: shot blasting is performed on the heat-treated parts to eliminate stress concentration caused by heat treatment and improve the fatigue strength of the connecting rings; then anti-corrosion paint is sprayed, and the dry film thickness of the paint is 70µm-120µm.

[0013] It also includes S4, performance verification: simulating the working environment in a mine, the prepared connecting ring is subjected to damage and self-repair tests to verify the effectiveness of the self-repair function.

[0014] Compared with the prior art, the beneficial effects of this invention are: 1. The mining vertical connecting ring of the present invention adds self-healing material to the original design, enabling the connecting ring to automatically repair surface and internal damage in the complex working conditions of the mine, effectively extending the service life of the connecting ring. Compared with traditional connecting rings, the service life can be increased by 30%-50%.

[0015] 2. This invention reduces equipment downtime and maintenance time caused by damage to the connecting links, improves the continuity and production efficiency of mining operations, and reduces maintenance costs.

[0016] 3. The automatic repair function of this invention reduces the risk of chain link breakage, improves the safety of mining machinery and equipment operation, and reduces the probability of safety accidents.

[0017] 4. This invention uses 23MnNiMoCr54 alloy steel as the base material, combined with self-healing material components and special preparation process, to ensure the original high strength, high toughness and other excellent mechanical properties of the connecting ring, while endowing it with self-healing characteristics, and has good comprehensive performance. Attached Figure Description

[0018] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings in the following description are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0019] The structures, proportions, sizes, etc. illustrated in this specification are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed herein, and are not intended to limit the conditions under which the present invention can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size, without affecting the effects and objectives that the present invention can produce, should still fall within the scope of the technical content disclosed in the present invention.

[0020] Figure 1 This is a split view of the connecting ring of the present invention; Figure 2 This is an assembly diagram of the connecting ring of the present invention.

[0021] Where: 1 is the connecting link. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. These descriptions are only for further illustrating the features and advantages of the present invention, and not for limiting the claims of the present invention. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0023] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0024] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0025] This embodiment uses 23MnNiMoCr54 alloy steel raw material, alumina nanoparticles, nickel-titanium shape memory alloy particles, and a metal salt catalyst to prepare a raw material for a self-healing vertical connecting link for mining. The manufacturing method of the connecting link 1 includes the following steps: S1. Raw material prefabrication, forging and heat treatment: S11. Raw material prefabrication: Alumina nanoparticles accounting for 6% of the total weight of alloy steel are uniformly embedded on the surface of 23MnNiMoCr54 alloy steel powder using high-energy ball milling technology to form a "core-shell" structured composite powder. The above composite powder is then three-dimensionally mechanically mixed with shape memory alloy particles accounting for 3% of the total weight of alloy steel and 1% of catalyst, and the raw material is obtained by spark plasma sintering technology.

[0026] S12. The raw materials are made into steel billets with a diameter of Φ70mm and placed in a special mold. Then, they are forged in a temperature range of 800℃-1000℃. Through multiple forging and upsetting operations, a vertical chain ring forging billet of Φ42×146mm is produced.

[0027] S13. Normalizing: The Φ42×146mm vertical chain ring forging billet is normalized, with a heating temperature of 900℃, held for 3 hours, and then air-cooled to room temperature. S2. Machining and heat treatment of the connecting parts: S21. Place the Φ42×146mm vertical connecting ring forging blank into a special machining fixture for clamping and positioning. Use a CNC milling machine to process the reference surface, tenon, and mortise. After assembling in pairs, process the pin holes. S22. The processed chain links are quenched using a gas carburizing furnace at a temperature of 890℃ for 1 hour, and then quickly cooled in water. After quenching, they are tempered using a pit-type tempering furnace at a temperature of 490℃ for 4 hours, followed by air cooling. The hardness after tempering is HRC40.

[0028] S3. Surface treatment: The Φ42×146mm vertical connecting ring after heat treatment is shot blasted and coated with anti-corrosion paint with a dry film thickness of 100µm.

[0029] S4. Performance Testing: After assembling the prepared connecting links with the mining chain, they were placed on a tensile testing machine and a fatigue testing machine for tensile strength and fatigue strength testing. The test results showed a breaking load of 1930kN and no breakage after 105,000 fatigue cycles. At the same time, simulating the working environment in a mine, fatigue performance tests were conducted on the prepared connecting links and connecting links made of materials without self-healing components. The results are shown in Table 1.

[0030] Table 1. Fatigue performance test results of the connecting rings prepared in this embodiment and those made of materials without self-healing components. Linkage specifications raw materials Frequency times / min Lower limit of pulsating load / kN Pulsating load limit / kN Loop count Φ42×146mm Contains self-repairing ingredients 230 139 693 94690 Does not contain self-healing ingredients 71696 The above description only illustrates the preferred embodiments of the present invention. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention, and all such changes should be included within the protection scope of the present invention.

Claims

1. A self-healing vertical connecting link for mining, characterized in that: The connecting link is based on 23MnNiMoCr54 alloy steel and is made from a steel billet with added self-healing material components; the self-healing material components include nanoparticles, shape memory alloy particles and catalysts; The nanoparticles are used to fill micro-cracks and wear pits on the surface of the connecting links, and account for 5%-8% of the total weight of 23MnNiMoCr54 alloy steel; The shape memory alloy particles are used to fill cracks inside the connecting links and account for 3%-5% of the total weight of 23MnNiMoCr54 alloy steel; The catalyst is used to promote the self-healing reaction and accounts for 1%-2% of the total weight of 23MnNiMoCr54 alloy steel.

2. The self-healing vertical connecting link for mining as described in claim 1, characterized in that: The nanoparticles are alumina nanoparticles, which have high hardness and thermal stability; the shape memory alloy particles are nickel-titanium shape memory alloy particles, which have wear resistance and corrosion resistance, and the phase transformation temperature Af point is adjusted to 45℃-60℃ to adapt to the temperature rise of downhole equipment operation; the catalyst is a metal salt catalyst, which can release ions to catalyze the repair reaction in a humid environment.

3. The self-healing vertical mining link according to claim 2, characterized in that: When used in underground mines, the connecting ring forms a three-level synergistic self-healing mechanism: when slight wear occurs on the surface, the exposed alumina nanoparticles provide excellent wear resistance; simultaneously, the local temperature rise caused by wear triggers the omagnetic phase transformation of adjacent shape memory alloy fibers, resulting in micro-shrinkage, compensating for the wear, and maintaining dimensional stability; when microcracks occur, the interaction of ambient moisture and catalysts causes the nanoparticles to migrate to the damaged area and solidify; when macro-cracks or local stress concentrations occur, the frictional temperature rise and mechanical load trigger the shape memory alloy phase transformation, generating compressive strain, thereby achieving automatic repair of surface and internal damage.

4. A method for manufacturing a self-healing vertical mining link according to any one of claims 1-3, characterized in that, Includes the following steps: S1. Raw material prefabrication, forging and heat treatment: 23MnNiMoCr54 alloy steel and self-healing material components are made into uniform steel billets using powder metallurgy process, the steel billets are forged, and then the forgings are normalized. S2. Machining and heat treatment of the connecting parts: Machining is performed on the connecting parts of the forgings after normalizing, and then the machined parts are quenched and tempered. S3. Surface treatment: The heat-treated parts are shot-blasted and then coated with anti-corrosion paint.

5. The manufacturing method of a self-healing vertical mining link according to claim 4, characterized in that, The specific process of S1 includes: S11. Raw material prefabrication: Alumina nanoparticles are uniformly embedded on the surface of 23MnNiMoCr54 alloy steel powder using high-energy ball milling technology to form a core-shell structured composite powder. The composite powder is then three-dimensionally mechanically mixed with shape memory alloy particles and a catalyst to prepare a uniform steel billet.

6. S12 Forging process: The S11 steel billet is sawn to size, and the special mold and the steel billet are heated evenly and thoroughly to the forging temperature at the same time to avoid excessive internal and external temperature difference and thermal stress; the forging temperature is 1150℃-1200℃ for the initial forging temperature and 850℃-900℃ for the final forging temperature; the steel billet is formed into the basic shape of the connecting ring through plastic deformation; S13. Normalizing process: Heat the forging to 850℃-930℃ at a heating rate of 2℃ / min-5℃ / min, hold for 1-3 hours and then cool in air to refine the grains and homogenize the microstructure.

7. The manufacturing method of a self-healing vertical mining link according to claim 5, characterized in that, In step S12, while forming the basic shape of the connecting ring through plastic deformation, grain refinement and internal defect compaction are achieved.

8. The manufacturing method of a self-healing vertical mining link according to claim 4, characterized in that, The specific process of S2 includes: S21. Machining process of connecting parts: The reference surface, tenon and mortise of the forging are machined with cutting tools. The machined parts are then assembled in pairs and the pin holes are machined. S22, Heat treatment process: Quenching: Heat the processed parts to 850℃-900℃ at a heating rate of 2℃ / min-5℃ / min, hold for 1-3 hours, and then water cool to room temperature; Tempering: Heat the quenched parts to 450℃-550℃ at a heating rate of 2℃ / min-5℃ / min, hold for 2-4 hours, and then air cool to room temperature.

9. A method for manufacturing a self-healing vertical mining link according to claim 4, characterized in that, The specific process of S3 is as follows: shot blasting is performed on the heat-treated parts to eliminate stress concentration caused by heat treatment and improve the fatigue strength of the connecting rings; then anti-corrosion paint is sprayed, and the dry film thickness of the paint is 70µm-120µm.

10. A method for manufacturing a self-healing vertical mining link according to claim 4, characterized in that, It also includes S4, performance verification: simulating the working environment in a mine, the prepared connecting ring is subjected to damage and self-repair tests to verify the effectiveness of the self-repair function.

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