Manufacturing method of vertical heavy-duty connecting links for mining, mining chains

Abstract

A manufacturing method for a vertical heavy-duty mining chain link and a mining chain, comprising the following process: machining according to product dimensions (leaving a fitting clearance) → primary stretching (to remove tensile stress) → heat treatment (to obtain the final material properties) → secondary stretching (to correct heat treatment deformation and remove internal stress). The deformation generated by heat treatment is absorbed by the reserved fitting clearance. Simultaneously, primary stretching is performed before heat treatment, and secondary stretching is performed after heat treatment to remove stress through two stretching processes. For parts subjected to alternating loads, this process avoids fatigue crack initiation caused by surface defects in machining and heat treatment. Ultimately, taking a φ48 vertical mining chain link as an example, the breaking load is ≥3400kN, and the fatigue cycles are ≥100,000, improving the reliability and service life of the connecting components and adapting to the increasingly stringent working conditions of coal mining; it fully meets the ultimate load requirements of current heavy-duty scraper conveyors with large mining heights and ultra-long working faces for the transmission chain link connecting parts.

Description

Technical Field

[0001] This invention relates to the field of mining chain links, and more particularly to a manufacturing method for a vertical heavy-duty mining chain link and a mining chain. Background Technology

[0002] Currently, the high-strength circular link chains in domestic coal mine underground conveying equipment are partially connected using vertical link joints. However, the performance of existing products is mostly designed according to standards such as MT / T 99-1997, and their breaking load and fatigue life (for example, the industry common requirement is a breaking load ≥2630kN and fatigue cycles ≥40,000) are no longer sufficient to fully meet the ultimate load requirements of the transmission chain link connectors for heavy-duty scraper conveyors in current high-extraction and ultra-long working faces. Insufficient performance can easily cause the link joint to become a weak link in the chain system, leading to unplanned downtime. Summary of the Invention

[0003] In order to solve the technical problems existing in the above-mentioned technologies, it is necessary to provide a method for manufacturing vertical heavy-duty connecting links for mining, so as to meet the ultimate load requirements of the transmission chain link connectors of heavy-duty scraper conveyors with large mining height and ultra-long working faces.

[0004] A method for manufacturing a vertical heavy-duty connecting chain link for mining includes the following steps:

[0005] Step S1: Forge the blank using a die forging method;

[0006] Step S2: Process the first and second half-rings according to their dimensions, with the bosses and grooves on the first and second half-rings having a clearance of 0.1mm-0.2mm.

[0007] Step S3: Assemble the first half-ring and the second half-ring into a connecting ring and stretch it once to remove stress concentration caused by processing and make the first half-ring and the second half-ring fit better.

[0008] Step S4: Lay the assembled chain links flat and perform quenching-tempering heat treatment;

[0009] Step S5: Take out the heat-treated connecting ring, perform secondary stretching to correct the heat treatment deformation and remove internal stress, and then process the pin hole to ensure that the pin hole will not be misaligned when the final product is under stress.

[0010] Step S6: Surface shot peening strengthening, shot peening intensity is 0.2 mmA.

[0011] Preferably, the tensile load of the first stretching is less than the tensile load of the second stretching.

[0012] Preferably, before the first and second stretching, graphite or lubricating oil needs to be applied to the mating surfaces of the first and second half-rings to create a lubricating film for better adhesion.

[0013] Preferably, in step S4, the heat treatment steps are as follows:

[0014] S41: Place the assembled connecting links flat in the furnace, leaving a gap between each connecting link;

[0015] S42: When the furnace temperature is raised to 600℃, the workpiece is sent in. When the furnace temperature is raised to 600℃ again, the workpiece is held for 145-155 minutes. Then the temperature is raised to 890℃ and held for 175-185 minutes.

[0016] S43: Remove the workpiece and place it in the quenching tank for quenching;

[0017] S44: When the tempering furnace temperature is raised to 400℃, the quenched workpiece is sent in. When the furnace temperature is raised to 400℃ again, the heat preservation is started and the heat preservation time is 295~305min.

[0018] S45: After tempering, the workpiece is air-cooled for ≥5 minutes.

[0019] Preferably, in step S42, the water temperature in the quenching tank is 22-24°C, the quenching time is 5 minutes, and the water temperature after the workpiece is immersed in the water is 24-30°C.

[0020] Preferably, in step S2, the first half-ring and the second half-ring have the same structure, and the two ends of the first half-ring and the second half-ring can be joined to form a ring structure. The right end of the first half-ring has a first boss and a first groove to the left of the first boss. The left end of the first half-ring has a second boss and a second groove to the left of the second boss. A first guide fixing groove is formed in the first groove, and the guide is provided on the top of the second boss.

[0021] Preferably, in step S5, pin holes are machined. There are several pin holes, namely a first pin hole, a second pin hole, a third pin hole, and a fourth pin hole. The first pin hole and the second pin hole are located at the two ends of the first half-ring, and the third pin hole and the fourth pin hole are located at the two ends of the second half-ring. Threads are provided in the first pin hole and the third pin hole. The first pin hole and the fourth pin hole are coaxial and concentric, and the diameter of the fourth pin hole is larger than the diameter of the first pin hole for guiding installation. The second pin hole and the third pin hole are coaxial and concentric, and the diameter of the second pin hole is larger than the diameter of the third pin hole for guiding installation.

[0022] Preferably, the first pin hole and the second pin hole are arranged along the longitudinal direction of the first half-ring, and the third pin hole and the fourth pin hole are arranged along the longitudinal direction of the second half-ring.

[0023] Preferably, the first pin hole and the second pin hole are arranged along the transverse direction of the first half-ring, and the third pin hole and the fourth pin hole are arranged along the transverse direction of the second half-ring.

[0024] A mining chain, comprising a mining vertical heavy-duty connecting link prepared by the mining vertical heavy-duty connecting link manufacturing method described above.

[0025] Compared with existing technologies, the manufacturing method of the vertical heavy-duty connecting chain ring for mining provided by this invention follows a process route of first machining (leaving a fitting clearance) according to the product dimensions → first stretching (to remove tensile stress) → heat treatment (to obtain the final material properties) → second stretching (to correct heat treatment deformation and remove internal stress). Heat treatment is an intermediate step that connects the preceding and following steps. The deformation generated during heat treatment is absorbed by the reserved fitting clearance. Simultaneously, a first stretching is performed before heat treatment, and a second stretching is performed after heat treatment to remove stress through two stretching processes. For parts subjected to alternating loads, this process avoids fatigue crack initiation caused by surface defects in machining and heat treatment. Ultimately, taking a φ48 vertical connecting chain ring for mining as an example, the breaking load is ≥3400kN, and the fatigue cycles are ≥100,000, improving the reliability and service life of the connecting components and adapting to the increasingly stringent working conditions of coal mining; it fully meets the ultimate load requirements of current heavy-duty scraper conveyors with large mining heights and ultra-long working faces for the transmission chain ring connecting components. Attached Figure Description

[0026] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a schematic diagram of the structure of the first embodiment of the present invention.

[0028] Figure 2 For the present invention Figure 1 Sectional view along direction A.

[0029] Figure 3 This is a schematic diagram of the structure of the second embodiment of the present invention.

[0030] Figure 4 For the present invention Figure 3 Sectional view along direction B.

[0031] Figure 5This is a schematic diagram of the structure of the first half-ring in the first embodiment of the present invention.

[0032] Figure 6 This is a schematic diagram of the structure of the second half-ring in the first embodiment of the present invention.

[0033] Figure 7 This is a schematic diagram of the structure of the first half-ring in the second embodiment of the present invention.

[0034] Figure 8 This is a schematic diagram of the structure of the second half-ring in the second embodiment of the present invention.

[0035] Figure 9 This is a front view of the first half-ring of the present invention (the positions of the first pin hole, second pin hole, third pin hole, fourth pin hole, and guide are omitted).

[0036] Figure 10 This is a top view of the first half-ring of the present invention (the positions of the first pin hole, second pin hole, third pin hole, and fourth pin hole are omitted).

[0037] Figure 11 This is a schematic diagram of the side of the first groove.

[0038] Figure 12 This is a fatigue test report of the connecting link of the sample of the present invention.

[0039] Figure 13 This is a static tensile test report of the chain link of the present invention.

[0040] In the figure: First half ring 01, first pin hole 11, second pin hole 12, first boss 13, first groove 14, second boss 15, second groove 16, first guide fixing groove 17, second half ring 02, third pin hole 21, fourth pin hole 22, third groove 23, third boss 24, fourth groove 25, fourth boss 26, second guide fixing groove 27, positioning pin 31, guide 32. Detailed Implementation

[0041] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0042] In the description of this invention, it should be understood that the terms "upper", "middle", "outer", "inner", "lower", etc., which indicate orientation or positional relationship, are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the components or elements referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as limiting this invention.

[0043] Please refer to Figure 1 As shown in Figure 11, a method for manufacturing a vertical heavy-duty connecting chain link for mining includes the following steps:

[0044] Step S1: Forge the blank using a die forging method;

[0045] Specifically, graphite is used for mold cavity lubrication in blank forging, which facilitates the flow and forming of forging metal during the die forging process, protects the mold cavity from wear and improves mold service life, and spheroidizes the forging blank for annealing.

[0046] Step S2: Process the first half-ring 01 and the second half-ring 02 according to their dimensions in the product, wherein the gap between the bosses and grooves on the first half-ring 01 and the second half-ring 02 is 0.1mm-0.2mm;

[0047] Specifically, a CNC machine tool is selected, and R parametric programming is used. The dimensions of the locking part are changed according to the size of the product, and the machining program is adaptively adjusted for processing. The clearance between the boss and the groove is 0.1mm-0.2mm.

[0048] Step S3: Assemble the first half-ring 01 and the second half-ring 02 into a connecting ring and stretch it once to remove the stress concentration generated during processing and make the first half-ring 01 and the second half-ring 02 fit together better.

[0049] Step S4: Lay the assembled chain links flat and perform quenching-tempering heat treatment;

[0050] Step S5: Take out the heat-treated connecting ring, perform secondary stretching to correct the heat treatment deformation and remove internal stress, and then process the pin hole to ensure that the pin hole will not be misaligned when the final product is under stress.

[0051] Step S6: Surface shot peening strengthening, shot peening intensity is 0.2 mmA.

[0052] Specifically, surface shot peening strengthens the connecting links by generating surface compressive stress, thus improving fatigue strength. Shot peening of the locking section reduces stress concentration at the rounded corners. The fatigue strength is optimal when the shot peening intensity is 0.2 mmA. The shot peening intensity has a significant impact on stress concentration at the rounded corners; the higher the shot peening intensity, the greater the stress concentration.

[0053] Therefore, this invention adopts a process route of first processing according to product dimensions (leaving a fitting clearance) → first stretching (to remove tensile stress) → heat treatment (to obtain the final material properties) → second stretching (to correct heat treatment deformation and remove internal stress). Heat treatment is an intermediate step that connects the first and second stretching. The deformation generated by heat treatment is absorbed by the reserved fitting clearance. At the same time, a first stretching is performed before heat treatment, and a second stretching is performed after heat treatment to remove stress through two stretching processes. For parts subjected to alternating loads, this process avoids fatigue crack initiation caused by surface defects in processing and heat treatment. Ultimately, taking the φ48 mining vertical connecting chain as an example, the breaking load is ≥3400kN and the fatigue cycle is ≥100,000 times, improving the reliability and service life of the connecting parts and adapting to the increasingly stringent working conditions of coal mining.

[0054] Meanwhile, without stretching treatment, the pin holes of the connecting links are machined in the "free state" when the connecting links are not under load. When the chain is put into use, the connecting links bear huge longitudinal tensile forces, and the first half-ring 01 and the second half-ring 02 will undergo slight elastic deformation, causing the originally coaxial pin holes to misalign. After the pin holes are misaligned, the positioning pin 31 is subjected to shearing and compressive forces, and the original fit clearance is destroyed, making it very easy to be squeezed out or ejected from the pin hole. However, the connecting links of this invention adopt "stretch drilling" technology. Before drilling, a stretching process is performed to simulate the tensile force of the actual chain load, so that the tooth contact is more closely fitted before drilling, ensuring that the pin holes remain coaxial under stress.

[0055] Please refer to the figure. Specifically, the dimensions of products of different specifications prepared by the above method are shown in Table 1.

[0056] Table 1

[0057]

[0058] Furthermore, the tensile load of the first stretching is less than the tensile load of the second stretching to remove the stress generated by the corresponding processing, and the second stretching simulates the actual working conditions to avoid the pin holes on the first half ring 01 and the second half ring 02 being misaligned during actual operation.

[0059] Specifically, the constant load tensile loads for primary and secondary tensioning of chain links of different specifications are shown in Table 2.

[0060] Table 2

[0061]

[0062] Furthermore, before the first and second stretching, graphite or lubricating oil needs to be applied to the mating surfaces of the first half-ring 01 and the second half-ring 02 to create a lubricating film for better adhesion. As a result, during stretching, the first half-ring 01 and the second half-ring 02 fit together better, resulting in a better stretching effect.

[0063] Furthermore, in step S4, the heat treatment process is as follows:

[0064] Material preparation: Using special tooling, lay the assembled connecting links flat, 32 pieces per furnace (4 pieces per material frame), and leave a gap between each connecting link;

[0065] The quenching medium is an environmentally friendly quenching medium with a concentration of (4-6)% and a light-shielding coefficient of 1.2; the water temperature in the quenching tank is 22-24℃; and the nitrogen pressure is 0.2 MPa.

[0066] Quenching: When the furnace temperature is raised to 600℃, the workpiece is sent in. When the furnace temperature is raised to 600℃ again (heating time is about 60 min), the workpiece is held for (150 ± 5) min. Then the temperature is raised to 890℃ (heating time is about 60 min) and held for (180 ± 5) min.

[0067] Remove the workpiece and place it in the quenching tank for quenching; the water temperature of the quenching tank is (22+2)℃, the quenching time is 5min, and the water temperature after the workpiece is immersed in the water is (27±3)℃; the draining time is ≥30s.

[0068] Tempering: When the tempering furnace temperature is raised to 400℃, the workpiece is sent in. When the furnace temperature is raised to 400℃ again (heating time is about 60 minutes), the workpiece is held for (300±5) minutes.

[0069] During quenching, specific heating-holding-heating-holding curves were defined: 600℃ for 145–155 min; heating to 890℃ for 175–185 min; tempering at 400℃ for 295–305 min. These parameters were designed for the specific material and structure of the φ48 large-size vertical connecting chain link, and worked in conjunction with the furnace loading method of "assembling and then placing it flat in the furnace".

[0070] Air cooling: After tempering, the workpiece is placed in an air cooling table for air cooling for ≥5 minutes. Hardness requirement: HRC (37-42).

[0071] Furthermore, in step S2, the first half-ring 01 and the second half-ring 02 have the same structure. The two ends of the first half-ring 01 and the second half-ring 02 can be engaged to form a ring structure. The right end of the first half-ring 01 has a first boss 13 (specifically, the first boss 13 is an inclined semi-conical boss, specifically, the outer side of the first boss 13 and the outer side of the end of the first half-ring 01 are on the same curved surface, and the inner side of the first boss 13 is a vertical arc surface), and a first groove 14 is located on the left side of the first boss 13. The left end of the first half-ring 01 has a second boss 15 (specifically, the cross-section of the second boss 15 is T-shaped), and a second groove 16 is located on the left side of the second boss 15. A first guide fixing groove 17 is opened in the first groove 14, and the guide 32 is provided on the top of the second boss 15.

[0072] Correspondingly, the right end of the second half-ring 02 has a third groove 23 adapted to the first boss 13 (the third groove 23 has the same structure as the second groove 16), the left side of the third groove 23 has a third boss 24 adapted to the first groove 14 (the third boss 24 has the same structure as the second boss 15), the left end of the second half-ring 02 has a fourth groove 25 adapted to the second boss 15 (the fourth groove 25 has the same structure as the first groove 14), the left side of the fourth groove 25 has a fourth boss 26 adapted to the second groove 16 (the fourth boss 26 has the same structure as the first boss 13), a second guide fixing groove 27 adapted to the guide fixing member on the top of the second boss 15 is formed in the fourth groove 25, and a guide member 32 adapted to the first guide fixing groove 17 is provided on the top of the third boss 24. Due to the darkness of the downhole environment, the first half-ring 01 and the second half-ring 02 are aligned and installed by the guide member 32. At the same time, the above-mentioned boss and groove cooperate to achieve a double positioning and double locking structure, which is more stable under force, has a larger contact surface, a tighter fit surface, and uniform force distribution.

[0073] The top of the first protrusion 13 abuts against and fits against the bottom of the third groove 23.

[0074] The top of the fourth protrusion 26 abuts against and fits against the bottom of the second groove 16.

[0075] Furthermore, in step S5, pin holes are machined. There are several pin holes, namely a first pin hole 11, a second pin hole 12, a third pin hole 21, and a fourth pin hole 22. The first pin hole 11 and the second pin hole 12 are located at the two ends of the first half-ring 01, and the third pin hole 21 and the fourth pin hole 22 are located at the two ends of the second half-ring 02. The first pin hole 11 and the third pin hole 21 are threaded. The first pin hole 11 and the fourth pin hole 22 are coaxial and concentric, and the diameter of the fourth pin hole 22 is larger than the diameter of the first pin hole 11 to facilitate the insertion of the mounting pin. The second pin hole 12 and the third pin hole 21 are coaxial and concentric, and the diameter of the second pin hole 12 is larger than the diameter of the third pin hole 21. The mounting pin has a gap (e.g., 0.02-0.05mm) with the second pin hole 12 and the fourth pin hole 22.

[0076] During installation, the first half-ring 01 and the second half-ring 02 are pre-guided by the guide 32 to tightly align with each other, ensuring that the first pin hole 11 and the fourth pin hole 22 are coaxial and concentric, and the second pin hole 12 and the third pin hole 21 are coaxial and concentric. This also prevents the first half-ring 01 and the second half-ring 02 from separating vertically. Then, guided by the fourth pin hole 22 and the second pin hole 12, the positioning pin 31 is inserted into the first pin hole 11 along the fourth pin hole 22 and threaded into the first pin hole 11, and into the third pin hole 21 along the second pin hole 12, thus fixing the first half-ring 01 and the second half-ring 02 and ensuring a more secure connection between the connecting rings. This also facilitates assembly. When the scraper chain breaks or needs to be replaced, the connecting rings can be quickly disassembled by removing the positioning pin 31 and moving the guide 32 out of the corresponding first guide fixing groove 17 and second guide fixing groove 27, which improves maintenance speed and shortens maintenance time. Secondly, the positioning pin 31 is threaded to the first pin hole 11 and the third pin hole 21. Compared with the spring cotter pins of the prior art, the positioning pin 31 of this application will not get stuck due to dirt adhesion in the harsh working conditions of narrow and high load downhole, avoiding time-consuming and labor-intensive installation and disassembly. Thirdly, due to the darkness of the downhole environment, it is not easy to align the pin holes on the first half-ring 01 and the second half-ring 02. The guide 32 makes it easier to align them, facilitating the connection of the corresponding pin holes of the positioning pin 31. Finally, when the connecting ring is pulled by the flat rings at both ends, it can give the first half-ring 01 and the second half-ring 02 a certain displacement margin (longitudinal displacement margin or lateral displacement margin), which can prevent the positioning pin 31 from being subjected to excessive radial shear force; at the same time, when the connecting ring is pulled by the flat rings at both ends, it can make the contact surfaces of the first half-ring 01 and the second half-ring 02 tighter and tighter, ensuring the connection stability of the connecting ring.

[0077] On the other hand, lubricating oil can be injected into the fourth pin hole 22 and the second pin hole 12. When the connecting ring is pulled by the flat rings at both ends, the lubricating oil flows out from the gap between the first pin hole 11 and the fourth pin hole 22 and the gap between the second pin hole 12 and the third pin hole 21 due to displacement. This continuously lubricates the mating surfaces of the first half ring 01 and the second half ring 02, which can prevent wear and facilitate disassembly and assembly.

[0078] Correspondingly, grease can also be applied to the mating surfaces of the first half-ring 01 and the second half-ring 02. Due to the displacement and movement of the first half-ring 01 and the second half-ring 02, an oil film can be formed on the mating surfaces of the first half-ring 01 and the second half-ring 02. On the one hand, this can prevent wear, and on the other hand, it can facilitate disassembly and assembly, preventing the first half-ring 01 and the second half-ring 02 from sticking together in the harsh downhole environment over a long period of time.

[0079] Specifically, the lower end of the positioning pin 31 is threaded, and the top of the positioning pin 31 is equipped with a pin cap. The diameter of the pin cap of the positioning pin 31 is larger than the diameter of the second pin hole 12 and the fourth pin hole 22. The lower end of the positioning pin 31 is connected to the first pin hole 11 and the third pin hole 21 by thread to achieve installation. Through the clearance fit between the positioning pin 31 and the second pin hole 12 and the third pin hole 21, the connection can be made firm. Due to the displacement clearance, the positioning pin 31 will move with the chain during the movement of the mining chain. The positioning pin 31 will not stick to the pin hole wall due to dirt, preventing the positioning pin 31 from getting stuck due to dirt adhesion, and avoiding the technical problem of "time-consuming and labor-intensive installation and disassembly".

[0080] Furthermore, the guide member 32 is a dovetail platform, and the first guide fixing groove 17 and the second guide fixing groove 27 are dovetail grooves, which can achieve upper and lower fixation while guiding the installation, preventing the first half ring 01 and the second half ring 02 from separating from each other.

[0081] In one embodiment, the first pin hole 11 and the second pin hole 12 are arranged along the longitudinal direction of the first half-ring 01, and the third pin hole 21 and the fourth pin hole 22 are arranged along the longitudinal direction of the second half-ring 02. This allows the first half-ring 01 and the second half-ring 02 to have a certain relative displacement margin in the transverse direction. This displacement margin is the gap between the mating surfaces of the first half-ring 01 and the second half-ring 02, which can prevent the positioning pin 31 from being subjected to excessive radial shear force. At the same time, when the connecting link is pulled by the flat rings at both ends, the mating surfaces of the first half-ring 01 and the second half-ring 02 can be pulled tighter and tighter, ensuring the connection stability of the connecting link.

[0082] Specifically, the first pin hole 11 is located on the top of the first boss 13 and faces downwards, the second pin hole 12 is located on the top of the first half ring 01 and communicates with the first groove 14, the third pin hole 21 is located on the top of the third boss 24 and faces downwards, and the fourth pin hole 22 is located at the bottom of one end of the second half ring 02 and communicates with the fourth groove 25.

[0083] In one embodiment, the first pin hole 11 and the second pin hole 12 are arranged along the transverse direction of the first half-ring 01, and the third pin hole 21 and the fourth pin hole 22 are arranged along the transverse direction of the second half-ring 02. When the connecting link moves laterally (i.e., moves along the central groove), the connecting link is pulled by the flat rings at both ends, which tightens the contact surfaces of the first half-ring 01 and the second half-ring 02, ensuring the connection stability of the connecting link. When the connecting link moves in an arc (i.e., rotates along the sprocket), the connecting link is acted upon by the sprocket, causing the first half-ring 01 and the second half-ring 02 to be pulled by the flat rings in a tangential direction perpendicular to the sprocket, which tightens the contact surfaces of the first half-ring 01 and the second half-ring 02, ensuring the connection stability of the connecting link. Meanwhile, when the service life of the connecting ring reaches the point where it needs to be disassembled, the wedge can be inserted into the first pin hole 11 along the fourth pin hole 22 or into the third pin hole 21 along the second pin hole 12 to apply external force to the wedge and push the first half ring 01 and the second half ring 02 apart for easy disassembly.

[0084] Specifically, the first pin hole 11 is located on the outside of the first boss 13 and faces inward; the second pin hole 12 is located on the side end of the first half ring 01 and communicates with the first groove 14; the third pin hole 21 is located on the outside of the third boss 24 and faces inward; and the fourth pin hole 22 is located on the side end of the second half ring 02 and communicates with the first groove 14.

[0085] Please refer to Figures 9 to 11 Furthermore, the first groove 14 and the fourth groove 25 have the same structure. The front opening of the first groove 14 is large. The first groove 14 is designed with a 2-4° tilt angle in the horizontal direction. The structure of the second boss 15 is the same as that of the third boss 24. The second boss 15 is also designed with a 2-4° tilt angle in the horizontal direction. When it is subjected to force in the horizontal direction, the tilt angle is used to tighten it (the more it is pulled, the tighter it becomes), the force is more uniform and the performance is better.

[0086] Furthermore, the upper opening of the first groove 14 is large, and the longitudinal slope of the first groove 14 is 5-10°. The longitudinal slope of the second protrusion 15 is also 5-10°. When subjected to longitudinal force, the anti-disengagement mechanism utilizes the inclined angle to tighten (the tighter it is pulled), resulting in more even force distribution and better performance. When the slope angle is too large, the wall thickness of the first groove 14 becomes thinner, causing cracking. When the slope angle is too small, the bottom width of the first groove 14 is close to the bottom width of the third protrusion 24. When the chain link is subjected to vertical force, the first groove 14 deforms, and the third protrusion 24 easily slips off.

[0087] The manufacturing method of this invention ultimately achieves a breaking load of ≥3400kN and fatigue life of ≥100,000 cycles for φ48 mining vertical heavy-duty connecting links. This application achieves both a higher breaking load (≥3400kN) and a superior fatigue life, an unexpected technical effect resulting from the synergistic effect of process parameters.

[0088] in, Figure 12 For fatigue testing of the sample connecting links, a 2000kN fatigue testing machine was used to conduct fatigue tests on the sample connecting links. The test report shows that the measured fatigue test values ​​of the three samples are 119820, 118114, and 123787. The fatigue test values ​​are much greater than the standard value (≥70000), indicating that the connecting links manufactured by this method fully meet the requirements for fatigue performance and have better performance.

[0089] in, Figure 13 For the static tensile test of the connecting link of the specimen, a 600t universal testing machine was used to stretch the connecting link. The test report shows that, without breaking, the measured value of the load elongation of specimen 1 is 1.32, the measured value of the breaking load is 4061.71kN, and the measured value of the total elongation at break is 12.12. The experimental value of the breaking load is greater than the standard value (≥3400kN), indicating that the connecting link manufactured by this method fully meets the requirements for breaking load and has better performance.

[0090] In one embodiment, the present invention provides a mining chain, including a mining vertical heavy-duty connecting link prepared by a method for manufacturing mining vertical heavy-duty connecting links.

[0091] In one embodiment, the present invention provides a scraper conveyor including the mining chain.

[0092] The above-disclosed embodiments are merely preferred embodiments of the present invention and should not be construed as limiting the scope of the invention. Those skilled in the art will understand that implementing all or part of the above-described embodiments and making equivalent changes in accordance with the claims of the present invention are still within the scope of the invention.

Claims

1. A method for manufacturing a vertical heavy-duty connecting chain link for mining, characterized in that: Includes the following steps, Step S1: Forge the blank using a die forging method; Step S2: Process the first and second half-rings according to their dimensions, with a clearance of 0.1-0.2mm between the bosses and grooves on the first and second half-rings; Step S3: Assemble the first half-ring and the second half-ring into a connecting ring and stretch it once to remove stress concentration caused by processing and make the first half-ring and the second half-ring fit better. Step S4: Lay the assembled chain links flat and perform quenching-tempering heat treatment; Step S5: Take out the heat-treated chain link, perform secondary stretching to correct the heat treatment deformation and remove internal stress, and then process the pin hole to ensure that the pin hole will not be misaligned when the final product is under stress. Step S6: Surface shot peening strengthening, with a shot peening intensity of 0.2 mmA.

2. The method for manufacturing a vertical heavy-duty connecting chain ring for mining according to claim 1, characterized in that: The tensile load of the first stretch is less than the tensile load of the second stretch.

3. The method for manufacturing a vertical heavy-duty connecting chain ring for mining according to claim 2, characterized in that: Before the first and second stretching, graphite or lubricating oil needs to be applied to the mating surfaces of the first and second half-rings to create a lubricating film for better adhesion.

4. The method for manufacturing a vertical heavy-duty connecting chain ring for mining according to claim 2, characterized in that: In step S4, the heat treatment process is as follows: S41: Place the assembled connecting links flat in the furnace, leaving a gap between each connecting link; S42: When the furnace temperature is raised to 600℃, the workpiece is sent in. When the furnace temperature is raised to 600℃ again, the workpiece is held for 145-155 minutes. Then the temperature is raised to 890℃ and held for 175-185 minutes. S43: Remove the workpiece and place it in the quenching tank for quenching; S44: When the tempering furnace temperature is raised to 400℃, the quenched workpiece is sent in. When the furnace temperature is raised to 400℃ again, the heat holding time is 295-305 minutes. S45: After tempering, the workpiece is air-cooled for ≥5 minutes.

5. The method for manufacturing a vertical heavy-duty connecting chain link for mining according to claim 4, characterized in that: In step S42, the water temperature in the quenching tank is 22-24℃, the quenching time is 5 minutes, and the water temperature after the workpiece is immersed in the water is 24-30℃.

6. The method for manufacturing a vertical heavy-duty connecting chain ring for mining according to claim 3, characterized in that: In step S2, the first half-ring and the second half-ring have the same structure. The two ends of the first half-ring and the second half-ring can be joined together to form a ring structure. The right end of the first half-ring has a first boss and a first groove to the left of the first boss. The left end of the first half-ring has a second boss and a second groove to the left of the second boss. A first guide fixing groove is formed in the first groove, and the guide is provided on the top of the second boss.

7. The method for manufacturing a vertical heavy-duty connecting chain link for mining according to claim 6, characterized in that: In step S5, pin holes are machined. There are several pin holes, namely a first pin hole, a second pin hole, a third pin hole, and a fourth pin hole. The first and second pin holes are located at the two ends of the first half-ring, and the third and fourth pin holes are located at the two ends of the second half-ring. Threads are provided in the first and third pin holes. The first and fourth pin holes are coaxial and concentric, and the diameter of the fourth pin hole is larger than the diameter of the first pin hole for guiding installation. The second and third pin holes are coaxial and concentric, and the diameter of the second pin hole is larger than the diameter of the third pin hole for guiding installation.

8. The method for manufacturing a vertical heavy-duty connecting chain ring for mining according to claim 7, characterized in that: The first and second pin holes are arranged along the longitudinal direction of the first half-ring, and the third and fourth pin holes are arranged along the longitudinal direction of the second half-ring.

9. The method for manufacturing a vertical heavy-duty connecting chain ring for mining according to claim 7, characterized in that: The first and second pin holes are arranged along the transverse direction of the first half-ring, and the third and fourth pin holes are arranged along the transverse direction of the second half-ring.

10. A mining chain, characterized in that: The vertical heavy-duty connecting chain ring for mining, as described in claim 9, is included.

Images