A hole preparation method for reinforcing interlayer connections of a pressure-sealed cavity structure

Abstract

This application provides a method for preparing holes for reinforcing interlayer connections in a pressure-sealed cavity structure. The method includes: pre-setting plug-weld hole areas on a first and second plate that are mating together; setting plug-weld holes in the plug-weld hole areas of the second plate; aligning the welding surface with the plug-weld holes to form plug-weld hole positions; melting welding wire within the plug-weld hole positions to form plug-weld metal, thereby forming a metallurgical bond with the welding surface and the inner wall of the plug-weld hole respectively; performing post-weld heat treatment on the welded pressure-sealed cavity structure; and machining screw holes and countersunk holes on the plug-weld metal. By pre-setting plug-weld holes on the second plate, the plug-weld metal forms a metallurgical bond with the welding surface and the hole wall, increasing the cladding contact area between the plug-weld metal and the two plates, enhancing the interlayer connection strength, and sealing the gaps between the two mating surfaces with the plug-weld metal, cutting off the path of oil lateral penetration along the interlayer gaps, thereby solving the leakage problem at the connection point of the screw holes between the plates.

Description

Technical Field

[0001] This application relates to the field of welding and manufacturing technology of pressure sealing cavity structure of coal mining machine, and in particular to a method for preparing holes for connecting the reinforcing layer of pressure sealing cavity structure and a pressure sealing cavity structure. Background Technology

[0002] During coal mining, the gears in the transmission system of the coal mining machine require lubrication and heat dissipation. Therefore, components such as the traction box housing of the coal mining machine have strict requirements for the sealing of the gear cavities. Currently, some coal mining machine housings are manufactured using plate welding. For this part of the housing, the welding quality requirements for the welds are extremely high, especially in the gear cavities where lubrication is required. Inspection requires a water pressure leakage test, pressurizing to 0.5 MPa and holding for 30 minutes. This necessitates that every relevant weld must be free of defects that could affect the sealing performance.

[0003] In actual manufacturing, some screw holes or small holes are directly connected between the plates. According to the traditional structural design, the plates are connected by welding around the fillet weld. The screw holes or small holes penetrate through the two layers of plates. During water pressure leakage test, leakage often occurs. This is mainly due to insufficient sealing between the fillet weld and the screw hole. Under pressure, defects such as pores in the weld, which are difficult to completely avoid, can communicate with the screw hole, leading to sealing failure and failing to meet the sealing performance requirements of the gear cavity.

[0004] In view of this, it is necessary to design a method for preparing holes for the reinforcing layer connection of a pressure-sealed cavity structure and a pressure-sealed cavity structure to solve one of the above technical problems. Summary of the Invention

[0005] This application provides a method for preparing holes for connecting the reinforcing layer of a pressure-sealing cavity structure and a pressure-sealing cavity structure, which can solve the leakage problem at the connection of screw holes between plates.

[0006] To achieve the above objectives, the technical solution provided in this application is as follows: This application provides a method for preparing holes for reinforcing interlayer connections in a pressure-sealed cavity structure. The pressure-sealed cavity structure includes a first plate and a second plate that are mated together. The preparation method includes the following steps: The structural redesign process involves pre-setting plug weld hole areas on the first and second plates, grinding the plug weld hole areas on the first plate to form a welding surface, and setting plug weld holes in the plug weld hole areas on the second plate. In the plug welding assembly step, the welding surface of the first plate is aligned with the plug welding hole of the second plate to form a plug welding hole position located between the two plates. In the plug welding step, the welding wire is melted in the plug welding hole to form plug welding metal, so that the plug welding metal forms a metallurgical bond with the welding surface and the inner wall of the plug welding hole respectively, thereby increasing the cladding contact area between the weld and the first plate and the second plate. Post-weld heat treatment step: Perform post-weld heat treatment on the pressure sealing cavity structure after plug welding is completed. The post-weld finishing step involves machining screw holes and countersunk holes on the plug weld metal, wherein the screw holes extend at least to the surface of the first plate.

[0007] Furthermore, before the plug welding assembly step, both sides of the plug welding hole are chamfered or deburred.

[0008] Furthermore, before the plug welding step, the first and second plates are preheated to a temperature of 50°C to 150°C.

[0009] Furthermore, in the plug welding step, MAG welding is used, and the welding current is 220A to 300A, and the welding voltage is 24V to 32V.

[0010] Furthermore, the post-weld heat treatment includes hydrogen removal treatment of the plug weld metal, specifically: heating the plug weld metal to 50°C to 200°C, and then covering it with insulation material to slow down the cooling rate.

[0011] Furthermore, the post-weld heat treatment also includes annealing the welded pressure sealing cavity structure, specifically: the annealing temperature is 480℃ to 530℃, the annealing temperature is maintained for 4h to 5h, and then it is naturally cooled to room temperature.

[0012] Furthermore, the diameter of the countersunk hole is smaller than the diameter of the plug weld hole, but larger than the diameter of the screw hole, so that the plug weld metal forms a complete annular sealing area around the screw hole and the countersunk hole.

[0013] This application also provides a pressure-sealed cavity structure for the gear cavity of a coal mining machine traction box, comprising a first plate and a second plate that are mated together, wherein the second plate has a through-hole for welding, the through-hole is filled with welding metal, the welding metal forms a metallurgical bond with the surface of the first plate facing the second plate and the inner wall of the welding hole of the second plate respectively; the second plate has a screw hole and a countersunk hole through the welding metal, the screw hole extending at least to the surface of the first plate.

[0014] Furthermore, the screw hole, countersunk hole, and plug welding hole are coaxially arranged.

[0015] Furthermore, the diameter of the countersunk hole is smaller than the diameter of the plug weld hole, but larger than the diameter of the screw hole, so that the plug weld metal forms a complete annular sealing area around the screw hole and the countersunk hole.

[0016] Compared with related technologies, the beneficial effects of this application are as follows: by pre-setting plug welding holes on the second plate, the plug welding metal forms a metallurgical bond with the welding surface of the first plate and the hole wall of the second plate, which significantly increases the cladding contact area between the weld and the two plates, thereby effectively enhancing the interlayer connection strength. Moreover, the plug welding metal completely seals the gap between the first plate and the second plate, cutting off the path of oil penetration laterally along the interlayer gap, thereby solving the leakage problem at the connection of the screw holes between the plates. Attached Figure Description

[0017] Figure 1 This is a flowchart of the hole preparation method for the reinforced interlayer connection of the pressure-sealed cavity structure in this application.

[0018] Figure 2 This is a schematic diagram of the pressure sealing cavity structure of this application.

[0019] Among them, 1-first plate, 2-second plate, 3-plug weld metal, 4-screw hole, 5-counterhole. Detailed Implementation

[0020] To enable those skilled in the art to better understand the technical solutions in this application, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this application.

[0021] In the various figures of this application, for ease of illustration, certain dimensions of structures or parts may be exaggerated relative to other structural parts; therefore, they are only used to illustrate the basic structure of the subject matter of this application.

[0022] This application provides a method for preparing holes for reinforcing interlayer connections in a pressure-sealed cavity structure. The pressure-sealed cavity structure includes a first plate and a second plate that are mated together. This preparation method can effectively solve the leakage problem at the connection of the screw holes in the pressure-sealed cavity structure.

[0023] like Figure 1 As shown, the preparation method includes the following steps: structural redesign step, plug welding assembly step, plug welding welding step, post-weld heat treatment step, and post-weld finishing step.

[0024] Specifically, the structural reconfiguration steps include: pre-setting plug weld hole areas on the first plate 1 and the second plate 2 that are mating together; grinding the plug weld hole areas on the first plate 1 to form a welding surface; setting plug weld holes in the plug weld hole areas on the second plate 2; forming plug weld metal 3 by pre-setting plug weld holes and melting welding wire in them; and forming metallurgical bonding between the plug weld metal 3 and the welding surface of the first plate 1 and the inner wall of the plug weld hole of the second plate 2, thereby increasing the cladding contact area and enhancing the interlayer bonding strength. Before the plug welding assembly step, both sides of the plug welding hole are chamfered or deburred to eliminate sharp corners, burrs and oxide layers on the edge of the hole. This allows the metal after the welding wire melts to fill the hole more smoothly and fuse fully with the hole wall, avoiding welding defects and thus improving the welding quality and sealing reliability of the plug welding hole area.

[0025] The plug welding assembly step includes aligning the welding surface of the first plate 1 with the plug welding hole of the second plate 2 to form a plug welding hole position located between the two plates, which facilitates the implementation of subsequent plug welding steps. The plug welding hole position includes the plug welding hole and the area where the first plate 1 and the second plate 2 meet.

[0026] In the plug welding step, the welding wire is melted in the plug welding hole to form plug welding metal 3, so that the plug welding metal 3 forms a metallurgical bond with the welding surface and the inner wall of the plug welding hole, thereby increasing the cladding contact area between the weld and the first plate 1 and the second plate 2. The plug welding metal 3 completely seals the gap between the two plates, cutting off the path of oil seeping laterally along the interlayer gap, thereby solving the leakage problem at the connection of the screw holes between the plates.

[0027] Before the plug welding step, the first plate 1 and the second plate 2 are preheated at a temperature of 50°C to 150°C to reduce the temperature gradient between the welding area and the base material, slow down the post-weld cooling rate, provide sufficient time for the diffusion and escape of hydrogen atoms in the plug weld metal 3, avoid the generation of hardened structure and cold cracks, and thus ensure the density of the plug weld metal 3 and the mechanical properties of the overall structure.

[0028] In the plug welding process, MAG welding is used, with a welding current of 220A to 300A and a welding voltage of 24V to 32V to ensure that the welding wire is fully melted and maintains a certain fluidity, so that the plug welding metal 3 can uniformly fill the entire plug welding hole and form a metallurgical bond with the hole wall and the welding surface.

[0029] Post-weld heat treatment specifically involves heat-treating the pressure-sealed cavity structure after plug welding. Post-weld heat treatment can eliminate residual welding stress, stabilize shell dimensions, facilitate post-weld finishing steps, and enable the shell to meet the requirements of a 0.5MPa water pressure leakage test with a pressure holding time of 30 minutes.

[0030] The post-weld heat treatment includes hydrogen removal treatment of the plug weld metal 3 and annealing treatment of the welded pressure sealing cavity structure.

[0031] The hydrogen removal treatment specifically involves heating the plug weld metal 3 to 50°C to 200°C, then covering it with insulating material to slow down the cooling rate, promote hydrogen escape from the weld, and prevent cold cracking. In this application, the hydrogen removal treatment can be performed on-site using a manual welding torch, which is convenient and easy to implement; the time is determined according to the size of the plug weld metal 3, and this application does not impose any limitation. Annealing the shell involves heating the welded pressure-sealing cavity structure in an annealing furnace at a temperature of 480℃ to 530℃ for 4 to 5 hours, followed by natural cooling to room temperature. This process allows residual welding stress to be fully relaxed and released at high temperatures, preventing deformation or micro-cracks and stabilizing the overall dimensions of the pressure-sealing cavity structure. This provides a stable, stress-free substrate for the subsequent precision machining of the threaded holes and countersunk holes, thereby ensuring the machining accuracy of the final threaded holes and their dimensional stability during long-term use.

[0032] Post-weld finishing includes machining screw holes 4 and countersunk holes 5 on the weld metal 3. The screw holes 4 extend at least to the surface of the first plate 1 to provide a detachable threaded connection for the pressure sealing structure. Machining screw holes 4 and countersunk holes 5 on the weld metal 3 does not damage the metallurgical bond between the weld metal 3 and the inner wall of the weld hole, so that the outer periphery of the screw holes 4 and countersunk holes 5 forms a complete annular sealing area. Thus, when assembling external components, after the bolts pass through the countersunk holes 5 and screw holes 4 in sequence, the weld metal 3 acts as a dense annular sealing barrier to completely isolate the pressure medium outside the interlayer gap, avoiding the formation of leakage channels that penetrate the interlayer.

[0033] Depending on the construction requirements, the screw hole 4 can extend to the surface of the first plate 1 or extend into the interior of the first plate 1.

[0034] The diameter of the countersunk hole 5 is smaller than the diameter of the plug welding hole and larger than the diameter of the screw hole 4, so that the plug welding metal 3 forms a complete annular sealing area around the screw hole 4 and the countersunk hole 5.

[0035] This application also provides a pressure-sealed cavity structure for the gear cavity of a coal mining machine traction box, such as... Figure 2As shown, the pressure sealing cavity structure includes a first plate 1 and a second plate 2 that are mated together. The second plate 2 has a through-hole for welding, which is filled with welding metal 3. The welding metal 3 forms a metallurgical bond with the surface of the first plate 1 facing the second plate 2 and the inner wall of the welding hole of the second plate 2, achieving a seamless fixed connection between the two plates and sealing the gaps between the mating surfaces. The second plate 2 has a screw hole 4 and a countersunk hole 5 that pass through the welding metal 3. The screw hole 4 extends to the surface of the first plate 1 or extends to the interior of the first plate 1, so that the threaded connection area is completely located in the dense welding metal 3 solid body, eliminating the physical path of oil seeping laterally along the gaps between the plates in the original structure, thereby ensuring the sealing performance of the gear cavity under a pressure of 0.5MPa, which is suitable for high-strength and high-sealing working environments such as coal mining machine traction boxes.

[0036] The screw hole 4, countersunk hole 5, and plug welding hole are coaxially arranged so that the plug welding metal 3 forms a uniform annular sealing area around the screw hole 4, avoiding the risk of local cladding layer being too thin or local exposure to interlayer gaps due to eccentricity, and further ensuring the uniformity and reliability of the seal.

[0037] The diameter of the countersunk hole 5 is smaller than the diameter of the plug welding hole and larger than the diameter of the screw hole, so that the plug welding metal 3 forms a complete annular sealing area around the screw hole 4 and the countersunk hole 5. When external components are assembled into the pressure sealing cavity structure, the plug welding metal 3 forms a complete annular sealing area around the screw hole 4 and the countersunk hole 5.

[0038] In summary, the hole preparation method for reinforcing interlayer connections in the pressure sealing cavity structure of this application pre-sets plug welding holes on the second plate 2, so that the plug welding metal forms a metallurgical bond with the welding surface of the first plate 1 and the hole wall of the second plate 2, which significantly increases the cladding contact area between the weld and the two plates, thereby effectively enhancing the interlayer connection strength. In addition, the plug welding metal 3 completely seals the gap between the mating surfaces of the first plate 1 and the second plate 2, cutting off the path of oil lateral penetration along the interlayer gap, thereby solving the leakage problem at the connection of the screw holes between the plates.

[0039] It should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This way of describing the specification is only for clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

[0040] The detailed descriptions listed above are merely specific illustrations of feasible embodiments of this application and are not intended to limit the scope of protection of this application. All equivalent embodiments or modifications made without departing from the spirit of the art of this application should be included within the scope of protection of this application.

Claims

1. A method for preparing holes for reinforcing interlayer connections in a pressure-sealed cavity structure, the pressure-sealed cavity structure comprising a first plate and a second plate that are mated together, characterized in that... Includes the following steps: The structural redesign process involves pre-setting plug weld hole areas on the first and second plates, grinding the plug weld hole areas on the first plate to form a welding surface, and setting plug weld holes in the plug weld hole areas of the second plate. In the plug welding assembly step, the welding surface of the first plate is aligned with the plug welding hole of the second plate to form a plug welding hole position located between the two plates. In the plug welding step, the welding wire is melted in the plug welding hole to form plug welding metal, so that the plug welding metal forms a metallurgical bond with the welding surface and the inner wall of the plug welding hole respectively, thereby increasing the cladding contact area between the weld and the first plate and the second plate. Post-weld heat treatment step: Perform post-weld heat treatment on the pressure sealing cavity structure after plug welding is completed; The post-weld finishing step involves machining screw holes and countersunk holes on the plug weld metal, wherein the screw holes extend at least to the surface of the first plate.

2. The method for preparing holes for reinforcing interlayer connections in a pressure-sealed cavity structure as described in claim 1, characterized in that, Before the plug welding assembly step, both sides of the plug welding hole are chamfered or deburred.

3. The method for preparing holes for reinforcing interlayer connections in a pressure-sealed cavity structure as described in claim 1, characterized in that, Before the plug welding step, the first and second plates are preheated to a temperature of 50°C to 150°C.

4. The method for preparing holes for reinforcing interlayer connections in a pressure-sealed cavity structure as described in claim 1, characterized in that, In the plug welding process, MAG welding is used, and the welding current is 220A to 300A, and the welding voltage is 24V to 32V.

5. The method for preparing holes for reinforcing interlayer connections in a pressure-sealed cavity structure as described in claim 1, characterized in that, The post-weld heat treatment includes hydrogen removal treatment of the plug weld metal, specifically: heating the plug weld metal to 50°C to 200°C, and then covering it with insulation material to slow down the cooling rate.

6. The method for preparing holes for reinforcing interlayer connections in a pressure-sealed cavity structure as described in claim 5, characterized in that, The post-weld heat treatment also includes annealing the pressure sealing cavity structure, specifically: the annealing temperature is 480℃ to 530℃, the annealing temperature is maintained for 4h to 5h, and then it is naturally cooled to room temperature.

7. The method for preparing holes for reinforcing interlayer connections in a pressure-sealed cavity structure as described in claim 1, characterized in that, The diameter of the countersunk hole is smaller than the diameter of the plug weld hole but larger than the diameter of the screw hole, so that the plug weld metal forms a complete annular sealing area around the screw hole and the countersunk hole.

8. A pressure-sealed cavity structure for the gear cavity of a coal mining machine traction box, comprising a first plate and a second plate that are mated to each other, characterized in that... The second plate has a through-hole for welding, which is filled with welding metal. The welding metal forms a metallurgical bond with the surface of the first plate facing the second plate and the inner wall of the welding hole of the second plate. The second plate has a screw hole and a countersunk hole that pass through the welding metal. The screw hole extends at least to the surface of the first plate.

9. The pressure-sealed cavity structure as described in claim 8, characterized in that, The screw hole, countersunk hole, and plug weld hole are coaxially arranged.

10. The pressure-sealed cavity structure as described in claim 8, characterized in that, The diameter of the countersunk hole is smaller than the diameter of the plug weld hole but larger than the diameter of the screw hole, so that the plug weld metal forms a complete annular sealing area around the screw hole and the countersunk hole.

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