A manufacturing method of a 1 / 2-petal mining mill barrel end flange without hardfacing

Abstract

This invention discloses a manufacturing method for a half-section mining mill cylinder end flange without surfacing welding, belonging to the field of riveting and welding. The method mainly includes: S1, determining the circumference compensation amount of the end flange based on the number of end flange segments, the number of mating surfaces, and the shrinkage of the circumferential weld in the final product, to offset welding deformation and eliminate the need for subsequent surfacing welding; S2, assembling the cylinder plate and the end flange, controlling the misalignment and perpendicularity between the cylinder plate and the end flange; S3, hoisting the cylinder onto a rotating platform and performing circumferential weld welding; S4, after the circumferential weld welding is completed, cutting the net dimensions of the cylinder plate on the rotating platform according to the inner centerline of the cylinder, and cutting bevels, then assembling and welding the longitudinal flanges on the rotating platform; S5, after the longitudinal flange welding is completed, hoisting the cylinder onto a riveting platform and disassembling it into two half-cylinders. Experiments show that this invention can solve the problems of high safety risks, large auxiliary consumption, and difficult control of surfacing welding quality in existing processes, significantly improving production efficiency and product quality.

Description

Technical Field

[0001] This invention belongs to the field of riveting and welding, and specifically relates to a manufacturing method for a 1 / 2-section mining mill cylinder end flange without overlay welding. Background Technology

[0002] Mining mills are core equipment in mining grinding operations. Their cylinders typically adopt a segmented structure to accommodate the manufacturing, transportation, and on-site installation requirements of large-scale equipment. The segmented cylinder is mainly assembled and welded from components such as cylinder plates and end flanges. During the manufacturing process, the flatness, parallelism, and overall dimensional tolerances of the flange surfaces must be ensured to meet the sealing and structural strength requirements of the mining mill during operation.

[0003] Currently, for 1 / 2 split cylindrical structures, the conventional assembly and welding process is as follows: First, the end flanges of the cylindrical body are made as a whole circle, then cut into semicircles and temporarily fixed with process connecting plates, and assembled into a whole circle; then, the two semi-cylinder plates are hoisted into place and assembled with the end flanges, while the process connecting plates are used to rigidly fix the two semi-cylinders. Next, the two corresponding semi-flanges at the other end are hoisted and assembled with the two semi-cylinder plates, and the process connecting plates are used to rigidly fix them; after assembly, circumferential welds are performed, then longitudinal flanges are installed and longitudinal welds are performed, and finally the process connecting plates are removed to obtain the two finished pieces, and overlay welding is performed on the mating surfaces of the end flanges to make the mating surfaces of the end flanges flush with the longitudinal flanges to meet the final processing requirements.

[0004] However, the above methods have significant shortcomings in actual production. First, the operational safety risks are high. After the end flanges are cut and separated, during the assembly of the semi-cylinder plates, jacks and other tooling are required for position adjustment and alignment. However, the workpiece stability is poor during this process, and risks such as tipping and slippage are likely to occur, making on-site safety management difficult. At the same time, the mating surfaces of the end flanges need to be welded to make them flush with the end face of the longitudinal flange. This process requires operation at a high platform, which poses significant safety hazards. In addition, the welding process is affected by factors such as heat deformation and limited operating space, resulting in a long welding cycle and high labor intensity. Secondly, the consumption of process auxiliary parts is high. After the end flange is cut, it needs to be temporarily welded into a whole circular structure through process connecting plates. The process connecting plates need to be removed after the process is completed and cannot be reused. In addition, auxiliary processes such as welding, cutting and grinding are added, which significantly increases labor and time costs and production efficiency is low. Thirdly, the quality of the welded area is difficult to guarantee after processing. After the end flange mating surface is welded and machined, defects such as porosity, slag inclusion, lack of fusion and flatness deviation are prone to occur. Due to the limitations of structural position and processing accuracy, the defect repair is difficult and the rework rate is high, making it difficult to consistently guarantee assembly accuracy and product quality.

[0005] Based on the above shortcomings, this invention proposes a manufacturing method for a 1 / 2-section mining mill cylinder end flange without overlay welding, which solves the long-standing problem of defects in the overlay welding process of the end flange end corner, reduces production costs, shortens the production cycle, optimizes the previous segmented mill manufacturing method, and has high engineering application value. Summary of the Invention

[0006] The purpose of this invention is to provide a manufacturing method for a 1 / 2-section mining mill cylinder end flange without overlay welding, which can effectively solve the problems of high safety risks, large auxiliary consumption, and difficulty in controlling the overlay welding quality in the existing process.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is: a manufacturing method for a 1 / 2-lobed mining mill cylinder end flange without weld overlay, comprising the following steps: S1. Determine the perimeter compensation amount of the end flange based on the number of end flange segments, the number of mating surfaces, and the shrinkage amount of the circumferential weld in the final product. The perimeter compensation amount includes at least the machining allowance reserved for each mating surface and the shrinkage compensation amount of the circumferential weld around the entire circle, which is used to offset welding deformation and eliminate the need for subsequent overlay welding. S2. Assemble the cylinder plate and the end flange, and control the misalignment and perpendicularity between the cylinder plate and the end flange. S3. Hoist the cylinder onto the rotating platform and perform circumferential welding; S4. After the circumferential weld is completed, the net dimensions of the cylinder plate are cut on the turntable according to the center line of the inner side of the cylinder, and the bevel is cut. The longitudinal flange is then assembled and welded on the turntable. S5. After the longitudinal flange welding is completed, the cylinder is hoisted to the riveting platform and disassembled into two half cylinders.

[0008] Furthermore, the machining allowance reserved on each mating surface is in the range of 10-20mm; the shrinkage compensation amount of the full circumferential weld is in the range of 15-25mm.

[0009] Furthermore, in step S2, the misalignment is no more than 2mm; the perpendicularity is no more than 1mm / 1000mm.

[0010] Furthermore, in step S3, the circumferential weld is performed using multi-layer, multi-pass welding. Specifically, the inner weld is first welded to half the depth of the bevel, then the outer bevel is cleaned and ground, then the outer bevel is fully welded, and finally the inner bevel is fully welded.

[0011] Furthermore, in step S4, when cutting the net dimension of the cylinder plate, the net dimension cutting line of the cylinder plate in the axial direction is drawn on the rotating die, with the inner center line of the cylinder as the reference. The net dimension cutting line is parallel to the inner center line of the cylinder.

[0012] Furthermore, in step S4, when assembling the longitudinal flange, the datum line is used as a reference to ensure that the distance between the reference line and the longitudinal flange is within the range of 90-110mm.

[0013] Furthermore, in step S5, after disassembling into two half-cylinders, the half-cylinders are repaired and corrected respectively. After passing the correction, a cylinder transport support is installed to obtain the finished product.

[0014] The beneficial effects of the above technical solution are as follows: This invention optimizes the end flange structure design and welding process, fundamentally eliminating the overlay welding step in traditional processes, and significantly improving the safety, economy, and product quality stability of the manufacturing process. Specifically, firstly, by increasing the inner and outer diameters of the end flanges to increase the circumference, the increased circumference compensates for post-weld shrinkage and end-face machining, allowing the mating surfaces of the two half-cylinders to meet machining requirements without the need for overlay welding, thus completely eliminating the quality risks associated with the overlay welding process. Secondly, the cylinder end flanges do not need to be cut before welding the cylinder plate to meet assembly requirements, reducing the welding and removal processes of the process connecting plates and avoiding safety risks such as tipping and slippage caused by using jacks when installing the cylinder plates with the segmented flanges. Thirdly, in traditional processes, end flange overlay welding can only be done manually with carbon dioxide gas shielded welding, and it involves multi-layer, multi-pass, and large-area overlay welding, requiring frequent arc ignition and extinguishing, which is difficult to operate. Even after ultrasonic testing, it is difficult to guarantee that there are no defects. However, this invention, through its overlay-free design, avoids the risks of defects such as porosity, slag inclusions, incomplete fusion, and flatness deviations on the overlay surface from the source, effectively improving product quality and assembly accuracy, while shortening the production cycle and reducing labor and time costs. Attached Figure Description

[0015] Figure 1 A flowchart is provided for the method of this invention.

[0016] The markings in the diagram are: 1. End flange, 2. Cylindrical plate, 3. Rotary head, 4. Longitudinal flange, 5. Half-cylinder. Detailed Implementation

[0017] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0018] It should be noted that, unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0019] To address the problems of high safety risks, high auxiliary consumption, and difficulty in controlling welding quality in existing processes, this invention designs a method for manufacturing a half-section mining mill cylinder end flange without welding, comprising the following steps: S1. Determine the circumference compensation of end flange 1 based on the number of end flange segments, the number of mating surfaces, and the shrinkage of the circumferential weld in the final product, and then process and manufacture it. S2. Assemble the cylinder plate 2 and the end flange 1, and control the misalignment and perpendicularity between the cylinder plate 2 and the end flange 1. S3. Hoist the cylinder onto the rotating platform 3 and perform circumferential welding; S4. After the circumferential weld is completed, cut the net dimensions of the cylinder plate 2 on the rotating mold 3 according to the center line of the inner side of the cylinder, and cut the bevel. Then, assemble and weld the longitudinal flange 4 on the rotating mold 3. After welding of S5 and longitudinal flange 4, the cylinder is hoisted to the riveting platform and disassembled into two half-cylinders 5.

[0020] The following describes in detail a method for manufacturing a 1 / 2-section mining mill cylinder end flange without welding, using a Φ6.7×10.0m overflow ball mill as an example. The manufacturing process is as follows: Figure 1 As shown.

[0021] S1. Based on the number of end flange segments, the number of mating surfaces, and the shrinkage of the circumferential weld in the final product, determine the circumferential compensation amount of end flange 1. The circumferential compensation amount includes at least the machining allowance reserved for each mating surface and the circumferential weld shrinkage compensation amount for the entire circle, which is used to offset welding deformation and eliminate the need for subsequent overlay welding.

[0022] In this embodiment, since the end flange 1 has 4 segments in the final product, that is, two cylindrical plates 2 correspond to two half flanges, each end flange 1 has 4 mating surfaces after being cut into two segments. Based on a machining allowance of 15mm for each mating surface and a 20mm compensation for shrinkage during circumferential welding, the total circumference compensation is 80mm. According to the circumference formula... Calculate the diameter The increase is 25.46mm, and in practice, the diameter increase is rounded up to 25mm. Accordingly, the inner and outer diameters of end flange 1 are both increased by 25mm during machining, while the remaining structural dimensions remain unchanged to ensure the assembly clearance with the cylinder and the overall matching of the flange.

[0023] S2. Assemble the cylinder plate 2 and the end flange 1, and control the misalignment and perpendicularity between the cylinder plate 2 and the end flange 1.

[0024] Hoist the two cylindrical plates 2 onto the end flange 1, adjust the position of the cylindrical plates 2, and control the misalignment of the inner circle of the cylindrical plates 2 and the end flange 1 to be no more than 2mm. Check the verticality of the cylindrical plates with a plumb line to ensure that it does not exceed 1mm / 1000mm. Repair any defects, and use process connecting plates to firmly connect the cylindrical plates 2 with each other and with the end flange 1.

[0025] Subsequently, the other end flange 1 is hoisted and a connecting plate is welded to the mating face of the end flange 1 to control deformation. After assembly, the outer circumference of the cylinder is measured, and the riveter transfers the centerline of the cylinder's length direction to the inner side of the cylinder. S3, hoist the cylinder onto the rotating platform 3 and perform circumferential welding.

[0026] The circumferential weld is performed using submerged arc welding, following a multi-layer, multi-pass welding process. First, the inner weld is welded to half the depth of the bevel. Then, the outer bevel is cleaned and ground. Finally, the outer bevel is welded to fill the gap, and the inner bevel is welded to fill the gap. After the circumferential weld is completed, the outer circumference of the cylinder is measured again, and the weld between the end flange 1 and the cylinder plate 2 is ground to ensure that it meets the process requirements.

[0027] S4. After the circumferential weld is completed, cut the net dimensions of the cylinder plate 2 on the rotating mold 3 according to the center line of the inner side of the cylinder, and cut the bevel. Then, assemble and weld the longitudinal flange 4 on the rotating mold 3.

[0028] The specific operation of cutting the net dimension number of the cylinder plate 2 is as follows: taking the inner center line of the cylinder as a reference, draw the axial net dimension cutting line of the cylinder plate 2 on the rotating mold 3. The net dimension cutting line is parallel to the inner center line of the cylinder.

[0029] When assembling longitudinal flange 4, use the scribed line on the flat plate as a reference, ensure that the reference line is 100mm away from longitudinal flange 4, and check the verticality. After confirming that it is qualified, weld longitudinal flange 4.

[0030] After welding of S5 and longitudinal flange 4, the cylinder is hoisted to the riveting platform and disassembled into two half-cylinders 5.

[0031] After the longitudinal flange welding is completed, the cylinder is hoisted onto the riveting platform. The inner and outer circumferences of the end flange 1 are measured, and the end flange 1 is cut into sections along the mating surface, taking into account the position of the longitudinal flange 4. The temporary connecting plate is then removed to obtain two half-cylinders 5. Subsequently, the half-cylinders 5 are repaired and straightened. After the straightening is qualified, cylinder transport supports are added to obtain the finished product.

[0032] Through the above steps, this embodiment successfully achieved weld-free manufacturing of end flange 1 in the Φ6.7×10.0m overflow ball mill project. This eliminated the weld overlay process and repeated disassembly and assembly of process connection plates in the traditional process, avoided the safety risks and welding defects of high-altitude weld overlay operations, and significantly improved production efficiency and product quality.

[0033] Finally, it should be noted that any parts of this invention not described in detail are prior art. Those skilled in the art will understand that the above descriptions are merely preferred embodiments of the invention and are not intended to limit the invention. Although the invention has been described in detail with reference to the foregoing examples, those skilled in the art can still modify the technical solutions described in the foregoing examples or make equivalent substitutions for some of the technical features. All modifications and equivalent substitutions made within the spirit and principles of the invention should be included within the scope of protection of the invention.

Claims

1. A method for manufacturing a half-section mining mill cylinder end flange without weld overlay, characterized in that, Includes the following steps: S1. Based on the number of end flange (1) segments, the number of mating surfaces, and the shrinkage of the circumferential weld in the final product, determine the circumferential compensation amount of the end flange (1). The circumferential compensation amount includes at least the machining allowance reserved for each mating surface and the circumferential weld shrinkage compensation amount of the whole circle, which is used to offset welding deformation and eliminate subsequent overlay welding. S2. Assemble the cylinder plate (2) and the end flange (1) and control the misalignment and perpendicularity of the cylinder plate (2) and the end flange (1); S3. Hoist the cylinder onto the rotating platform (3) and perform circumferential welding; S4. After the circumferential weld is completed, the net dimensions of the cylinder plate (2) are cut on the rotating mold (3) according to the center line of the inner side of the cylinder, and the bevel is cut. The longitudinal flange (4) is assembled and welded on the rotating mold (3). After the longitudinal flange (4) is welded, the cylinder is hoisted to the riveting platform and disassembled into two half cylinders (5).

2. The manufacturing method of the end flange of a 1 / 2-section mining mill cylinder without welding overlay as described in claim 1, characterized in that, The range of machining allowances reserved for each mating surface is 10-20mm; the range of shrinkage compensation for the full circumferential weld is 15-25mm.

3. The manufacturing method of a 1 / 2-section mining mill cylinder end flange without welding overlay as described in claim 1, characterized in that, In step S2, the misalignment is no more than 2mm; the perpendicularity is no more than 1mm / 1000mm.

4. The manufacturing method of a 1 / 2-section mining mill cylinder end flange without welding overlay as described in claim 1, characterized in that, In step S3, the circumferential weld is performed using multi-layer, multi-pass welding. Specifically, the inner weld is first welded to half the depth of the bevel, then the outer bevel is cleaned and ground, then the outer bevel is fully welded, and finally the inner bevel is fully welded.

5. A method for manufacturing a half-section mining mill cylinder end flange without weld overlay as described in claim 1, characterized in that, In step S4, when cutting the net size of the cylinder plate (2), the net size cutting line of the cylinder plate (2) is drawn on the rotating mold (3) with the inner center line of the cylinder as the reference. The net size cutting line is parallel to the inner center line of the cylinder.

6. A method for manufacturing a half-section mining mill cylinder end flange without weld overlay as described in claim 1, characterized in that, In step S4, when assembling the longitudinal flange (4), the datum line is used as the reference to ensure that the distance between the reference line and the longitudinal flange (4) is 90-110mm.

7. A method for manufacturing a half-section mining mill cylinder end flange without weld overlay as described in claim 1, characterized in that, In step S5, after disassembling into two half-cylinders (5), the half-cylinders (5) are repaired and corrected respectively. After the correction is qualified, the cylinder transport support is installed to obtain the finished product.

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