A method for maintaining a rotary drum used in blast furnace slag treatment

Abstract

This invention relates to the field of equipment maintenance for blast furnace slag treatment, and in particular to a method for maintaining a blast furnace slag treatment drum. Through systematic steps such as standardized drum leveling, precise dimensional measurement, controlled disassembly and grinding, load-adaptive beveling, overall assembly and reference positioning, welding processes, and standardized assembly, this method precisely solves the pain points of traditional drum maintenance, such as non-standard disassembly, low positioning accuracy, concentrated welding stress, and disordered maintenance procedures. It achieves efficient and precise replacement of the rails and base, avoiding resource waste and high costs caused by the complete scrapping of the drum due to damage to local components. Furthermore, it significantly improves the assembly accuracy and operational stability of the drum after maintenance, extends equipment lifespan, shortens maintenance time, and ensures the continuous and stable operation of the blast furnace slag treatment system.

Description

Technical Field

[0001] This invention relates to the field of equipment maintenance for blast furnace slag treatment, and in particular to a method for maintaining a rotary drum used for blast furnace slag treatment. Background Technology

[0002] Under the major trend of the steel industry's transformation towards energy conservation, environmental protection, and high efficiency, the resource-based treatment of blast furnace slag has become a key focus of the industry. Currently, the INBA method has become the mainstream blast furnace slag treatment technology because it can achieve continuous operation of pressurized water quenching and drum dewatering and slag separation of slag, and can recycle water, slag, and steam. As the core equipment in this process that realizes the functions of dewatering and slag separation, the operational stability of the drum directly determines the efficiency and environmental protection effect of the blast furnace slag treatment system. The drum's track and base are key load-bearing components, which are welded and fixed to the transmission cylinders at both ends of the drum. They need to bear the combined load of the drum body and the internal water and slag for a long time, and are the core support structure to ensure the stable operation of the drum.

[0003] Due to the complexity of blast furnace slag handling operations, the tracks and bases are subjected to harsh environments of high load, multi-media corrosion, and temperature fluctuations for extended periods. This makes them prone to problems such as ductile deformation, wear on load-bearing surfaces, and bolt breakage. In severe cases, fatigue cracking or even sudden fracture can occur. Damage to the tracks is simultaneously transmitted to the base, causing irreparable damage to the base directly welded to the transmission cylinder. Currently, the industry either scraps the entire drum if the tracks and bases are damaged. However, large blast furnace drums can have diameters of up to 5 meters, lengths exceeding 6 meters, and weigh 50-60 tons. New drums have long processing cycles and high costs. Scrapping an entire drum simply due to relatively low-value track and base damage results in significant resource waste and increased production costs.

[0004] However, existing drum maintenance technology still has many unresolved key problems: First, the assembly and fitting of new rails and bases lacks standardized procedures, the positioning benchmark is vague, and the axial and radial dimensional accuracy cannot be accurately controlled, resulting in uneven stress on the rails and shortening their service life; Second, the preheating before welding, the selection of welding methods, and the post-weld heat preservation measures lack scientific design, and the welding stress cannot be effectively released, which easily leads to crack defects; Third, the maintenance process lacks systematic design, and the steps are not connected in a disorderly manner, resulting in excessively long maintenance periods and affecting the normal iron tapping production of the blast furnace. Summary of the Invention

[0005] To address the problems of uneven stress on existing rails and bases due to the lack of standardized procedures, unclear positioning benchmarks, and inaccurate control of axial and radial dimensions, which shorten their service life, this invention provides a method for maintaining a rotary drum for blast furnace slag treatment.

[0006] To solve the above problems, the technical solution adopted by the present invention is as follows: A method for maintaining a rotary drum used for blast furnace slag treatment includes the following steps: S1. Place the drum horizontally and adjust the levelness to ≤1mm. Verify the levelness by using a level instrument to measure ≥4 evenly distributed measuring points on the outer circular surface of the transmission cylinder. S2. Measure and calibrate the installation fit dimensions of the old track, base, and transmission cylinder, including but not limited to the distance L1 (10000-12000mm) between the two ends of the drum and the distance L2 (9000-10000mm) between the track at both ends of the drum. S3. Use carbon arc gouging to remove the old track rails and their bases, and ensure that the flatness deviation of the cut surface is ≤2mm; remove the drive chain teeth and end water guide flanges that obstruct installation. S4. Grind and finish the mounting surface of the cut part and the outer surface of the transmission cylinder with a grinding wheel and / or a polishing machine; S5. Machining a welding bevel on the inner circular surface of the new base to fit the transmission cylinder. When the drum transmission load is ≤50t, the bevel angle α is 30°-45° and the depth h is 3-7mm; when the load is >50t, the bevel angle α is 45°-60° and the depth h is 7-10mm. S6. Pre-assemble the new track rail onto the base according to the working conditions, with an assembly gap of ≤0.5mm. Then, fit the base and track rail together from both ends of the transmission cylinder to the fixed position, avoiding collision with the surface of the transmission cylinder during the fitting process. S7. Using the end faces of the transmission cylinders at both ends of the drum as the axial reference and the outer circular surface as the radial reference, perform positioning and alignment according to the original data measured in step S2. The axial dimension accuracy is ≤2mm and the radial dimension accuracy is ≤1mm. Use ≥4 measuring points for verification. S8. Preheat the welding area to 100-150℃ before welding, use ≥6 points for symmetrical welding, and keep the temperature at 200-300℃ after welding for 2-4 hours to reduce welding stress. S9. Restore the dismantled transmission chain teeth and end water guide flanges, with an assembly gap ≤1mm. Through systematic steps such as standardized drum level calibration, precise dimensional measurement, controllable dismantling and grinding, load-adaptive beveling, overall assembly and benchmark positioning, welding processes, and standardized assembly, the pain points of traditional drum maintenance, such as non-standard dismantling, low positioning accuracy, concentrated welding stress, and disordered maintenance procedures, are precisely solved. This not only achieves efficient and precise replacement of the track and base, avoiding the waste of resources and high costs caused by the overall scrapping of the drum due to damage to local components, but also significantly improves the assembly accuracy and operational stability of the drum after maintenance, extends the service life of the equipment, shortens the maintenance period, and ensures the continuous and stable operation of the blast furnace slag treatment system.

[0007] Preferably, the transmission chain teeth in step S9 include a web; several teeth are fixedly mounted on the web; the web is fixedly mounted on the transmission cylinder by a bolt group, and the positioning deviation is <1mm. This transmission chain teeth, by adding a web to enhance structural strength and using a bolt group for fixed installation, achieves both quick assembly and disassembly and convenient maintenance, while the high-precision positioning of <1mm ensures the accuracy and stability of transmission meshing. This effectively reduces impact loads and wear during transmission, extends the service life of the transmission chain teeth and the entire drum, and further improves the reliability of drum operation.

[0008] Preferably, in step S7, axial positioning is achieved by using a 3m long aluminum alloy straightedge (straightness ≤0.1mm / m) against the side of the track, and verified by measuring with a 15m steel tape measure (accuracy ≤0.5mm). Radial positioning is verified by calibrating ≥6 evenly distributed marker points with a DS05 level, combined with bidirectional measurement and verification using a 0-grade right-angle ruler (accuracy ≤0.02mm / m) and a steel tape measure, ensuring that the positioning data deviation is ≤0.5mm. By using a combination of high-precision aluminum alloy straightedge, steel tape measure, DS05 level, and 0-grade right-angle ruler, along with multi-point evenly distributed calibration and bidirectional verification, not only is high-precision control of the track's axial and radial positioning deviations ≤0.5mm achieved, ensuring uniform force on the track, but the reliability of the positioning data is also improved. This effectively avoids problems such as drum vibration and accelerated component wear caused by positioning deviations, further ensuring the long-term stable operation of the drum.

[0009] Preferably, in step S8, the fillet weld is grade CK with a weld leg height of 6-10mm, and the butt weld is grade CS with a non-destructive testing pass rate of ≥98%. After welding, residual stress is eliminated by annealing at 550-650℃ for 1-2 hours. By clearly defining the grade standards and weld leg height parameters for fillet and butt welds, and ensuring a non-destructive testing pass rate of ≥98% to control welding quality, followed by precise temperature and time-controlled post-weld annealing, residual welding stress is effectively eliminated, cracks are prevented, and the connection strength and stability between the base and the transmission cylinder are significantly improved. This avoids component failures caused by welding defects during operation and ensures long-term reliable operation of the drum.

[0010] Preferably, the base is machined with bevels on both outer sides along the axial direction, with a bevel blunt edge dimension of 1-3mm. When the base thickness is 16-20mm, the bevel depth is 5-8mm; when the thickness is 20-25mm, the bevel depth is 8-12mm, ensuring that the weld penetration depth is ≥2 / 3 of the base thickness. The base is designed with bevels according to thickness grades and the blunt edge dimension is precisely controlled to ensure that the weld penetration depth is ≥2 / 3 of the base thickness, effectively avoiding welding defects such as incomplete penetration, significantly improving the weld strength and connection reliability between the base and the transmission cylinder, and laying a solid structural foundation for the long-term stable operation of the drum under high load.

[0011] Preferably, in step S4, the rust removal grade of the outer surface of the transmission cylinder after grinding reaches Sa2.5, the surface roughness of the cutting part Ra≤6.3μm, and the surface is free of oxide scale, spatter, and dents, with dent depth ≤0.5mm and area ≤5cm². By strictly controlling the rust removal grade, surface roughness, and defect limits of the transmission cylinder after grinding, impurities such as oxide scale and spatter are effectively removed, improving the fit between the new base and the transmission cylinder, avoiding impurities from affecting welding quality or causing subsequent corrosion, and ensuring the flatness of the mounting surface. This lays a solid foundation for subsequent precise positioning and reliable welding, supporting the long-term high-load stable operation of the drum.

[0012] Preferably, the process also includes a step of replacing the drum screen and frame: The deformed or damaged frame fixing base is replaced with Q235B or Q355B material, with a fixing base thickness of 12-16mm. The welding current is 160-200A, and the weld height is 8-12mm. After screen positioning and installation, the flatness is ≤2mm / m, flat and without twisting, with lateral segregation ≤1mm. Using suitable materials and precise parameters to replace and reinforce the frame fixing base, combined with high-standard screen installation precision control, not only strengthens the load-bearing strength and stability of the frame structure but also ensures the screen is flat and without segregation, improving the drum dewatering and slag removal efficiency, avoiding malfunctions caused by loose or deformed components, extending the service life of the screen and frame, and further ensuring the overall operational reliability of the drum.

[0013] Preferably, the screen uses trapezoidal cross-section wire with a mesh gap of 0.8mm. All screen fixing bolts and embedded nuts are replaced and securely welded, with the weld height matching the thickness of the connecting parts. The trapezoidal cross-section wire combined with a precise 0.8mm mesh gap enhances the wire structure's strength and anti-clogging ability, ensuring dewatering and slag removal accuracy. Furthermore, by replacing all fasteners and ensuring a secure weld that matches the thickness of the connecting parts, screen loosening and displacement are prevented, extending the screen's service life and further guaranteeing the drum's slag separation efficiency and operational stability.

[0014] Preferably, the process also includes a diversion plate replacement step: the weld spacing of the diversion plate is 100-150mm, the weld height is 3-5mm, there are no incomplete welds or slag inclusions, and the weld appearance fullness is ≥95%. By precisely controlling the weld spacing and weld height of the diversion plate, combined with the weld quality requirements of no incomplete welds, no slag inclusions, and high fullness, it is ensured that the diversion plate is installed firmly and reliably, without the risk of loosening or falling off, ensuring smooth and orderly slag and water diversion, improving the descaling efficiency of the drum, extending the service life of the diversion plate, and further enhancing the operational stability of the drum.

[0015] Preferably, after assembly, the drum undergoes heavy-duty anti-corrosion treatment: a modified polymeric wear-resistant and anti-corrosion coating (hardness ≥ HRC50) is applied. Before application, the drum is derusted to Sa2.5 level using manual tools and an electric angle grinder (speed 8000-10000 r / min). The dry film thickness of the coating is 200-300 μm. The ambient temperature during application is 5-35℃, the relative humidity is ≤85%, and the coating adhesion is ≥5MPa. Through high-standard rust removal pretreatment, the selection of a high-hardness modified polymeric wear-resistant and anti-corrosion coating, and precise control of coating thickness, application environment, and adhesion, the wear resistance and anti-corrosion performance of the drum surface are significantly improved. This effectively resists corrosion and wear in operating conditions, prevents coating peeling and failure, extends the overall service life of the drum, and ensures its long-term stable operation under harsh conditions.

[0016] As can be seen from the above technical solutions, the advantages of this invention are as follows: By systematically addressing the pain points of traditional drum maintenance, such as non-standard disassembly, low positioning accuracy, concentrated welding stress, and disordered maintenance process, through standardized drum level calibration, precise dimensional measurement, controllable disassembly and grinding, load-adaptive beveling, overall assembly and benchmark positioning, welding process, and standardized assembly, this invention precisely solves the problems of non-standard disassembly, low positioning accuracy, concentrated welding stress, and disordered maintenance process. It not only achieves efficient and precise replacement of the track and base, avoiding the waste of resources and high cost caused by the overall scrapping of the drum due to damage to local parts, but also significantly improves the assembly accuracy and operational stability of the drum after maintenance, extends the service life of the equipment, shortens the maintenance period, and ensures the continuous and stable operation of the blast furnace slag treatment system. Attached Figure Description

[0017] To more clearly illustrate the technical solution of the present invention, the accompanying drawings used in the description will be briefly introduced below. Obviously, the accompanying 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.

[0018] Figure 1 This is a schematic diagram of the structure of the drum of the present invention.

[0019] Figure 2 This is a schematic diagram of the structure of the transmission cylinder of the drum of the present invention.

[0020] Figure 3 This is a schematic diagram of the structure of the base of the present invention.

[0021] Figure 4 for Figure 3 Enlarged diagram of point A in the middle.

[0022] Figure 5 This is a schematic diagram of step S2 of the present invention.

[0023] Explanation of reference numerals in the attached drawings: 1-Drum, 2-Transmission cylinder, 3-Railway, 4-Base, 5-Transmission chain teeth, 6-End water guide flange, 7-Drainage plate, 8-Welding bevel; 101-Fixed seat, 102-Grid frame; 501-Body plate, 502-Tooth body. Detailed Implementation

[0024] To make the objectives, features, and advantages of this invention more apparent and understandable, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings of the specific embodiments. Obviously, the embodiments described below are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this patent, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this patent.

[0025] like Figure 1-5 As shown, a method for maintaining a rotary drum for blast furnace slag treatment includes the following steps: S1. Place the drum 1 horizontally and adjust the levelness to ≤1mm. Verify the levelness by using a level instrument at ≥4 evenly distributed measuring points on the outer circular surface of the transmission cylinder 2. S2. Measure and calibrate the installation fit dimensions of the old track 3, base 4, and transmission cylinder 2, including but not limited to the distance L1 (10000-12000mm) between the two end faces of the drum 1, the distance L2 (9000-10000mm) between the two ends of the track 3 of the drum 1; the distance between the end face of the track 3 away from the drum 1 and the outer surface of the transmission cylinder 2, used to position the track 3; measure the levelness of the top surface of the track 3; measure the distance from the top surface of the track 3 to the outer surface of the transmission cylinder 2. S3. Use carbon arc gouging to cut and remove the old track rail 3 and its base 4, and the flatness deviation of the cut surface is ≤2mm; remove the transmission chain teeth 5 and the end water guide flange 6 that hinder the installation. S4. Grind and finish the mounting surface of the cutting area and the outer surface of the transmission cylinder 2 using a grinding wheel and / or polishing machine; after grinding, the rust removal grade of the outer surface of the transmission cylinder 2 reaches Sa2.5, the roughness Ra of the mounting surface of the cutting area is ≤6.3μm, and the surface is free of oxide scale, spatter, and dents, with dent depth ≤0.5mm and area ≤5cm². By strictly controlling the rust removal grade, surface roughness, and defect limits of the transmission cylinder 2 after grinding, impurities such as oxide scale and spatter are effectively removed, improving the fit between the new base 4 and the transmission cylinder 2, avoiding impurities from affecting welding quality or causing subsequent corrosion, and ensuring the flatness of the mounting surface, laying a solid foundation for subsequent accurate positioning and reliable welding, and supporting the long-term high-load stable operation of the drum 1.

[0026] S5. A welding bevel 8 adapted to the transmission cylinder 2 is machined on the inner circular surface of the new base 4. When the drum transmission load is ≤50t, the bevel angle α is 30°-45° and the depth h is 3-7mm; when the load is >50t, the bevel angle α is 45°-60° and the depth h is 7-10mm. Bevels are machined on both outer sides of the base 4 along the axial direction. The bevel blunt edge size is 1-3mm. When the thickness of the base 4 is 16-20mm, the bevel depth is 5-8mm; when the thickness is 20-25mm, the bevel depth is 8-12mm, ensuring that the welding penetration depth is ≥2 / 3 of the thickness of the base 4. The bevels of the base 4 are designed according to the thickness and the blunt edge size is precisely controlled to ensure that the welding penetration depth is ≥2 / 3 of the thickness of the base 4, effectively avoiding welding defects such as incomplete penetration, significantly improving the welding strength and connection reliability of the base 4 and the transmission cylinder 2, and laying a solid structural foundation for the long-term high-load stable operation of the drum 1.

[0027] S6. Pre-assemble the new track 3 onto the base 4 according to the working conditions. The assembly gap is ≤0.5mm. The base 4 and the track 3 are assembled from both ends of the transmission cylinder 2 to the fixed position. Avoid collision with the surface of the transmission cylinder 2 during the assembly process. S7. Using the end faces of the transmission cylinders 2 at both ends of the drum 1 as the axial reference and the outer circular surface as the radial reference, perform positioning and alignment according to the original data measured in step S2. The axial dimension accuracy is ≤2mm, and the radial dimension accuracy is ≤1mm. ≥4 measuring points are used for verification. For axial positioning, a 3m long aluminum alloy straightedge (straightness ≤0.1mm / m) is used to fit against the side of the track 2, and a 15m steel tape measure (accuracy ≤0.5mm) is used for measurement and verification. For radial positioning, ≥6 evenly distributed marking points are calibrated using a DS05 level instrument, and bidirectional measurement is performed using a 0-grade right-angle ruler (accuracy ≤0.02mm / m) + steel tape measure to ensure that the positioning data deviation is ≤0.5mm. By employing a combination of high-precision aluminum alloy straightedge, steel tape measure, DS05 level, and 0-grade right-angle ruler for measurement, along with a positioning method that combines multi-point uniform distribution calibration and bidirectional verification, not only was high-precision control of the axial and radial positioning deviation of track 3 ≤ 0.5mm achieved, ensuring uniform force on track 3, but the reliability of positioning data was also improved. This effectively avoids problems such as vibration during drum 1 operation and accelerated wear of components caused by positioning deviation, further ensuring the long-term stable operation of drum 1.

[0028] S8. Preheat the welding area to 100-150℃ before welding, using ≥6-point symmetrical welding, and maintain the temperature at 200-300℃ for 2-4 hours after welding to reduce welding stress. The fillet weld grade is CK, with a weld leg height of 6-10mm, and the butt weld grade is CS, with a non-destructive testing pass rate of ≥98%. After welding, anneal at 550-650℃ to eliminate residual stress, with a holding time of 1-2 hours. By clearly defining the grade standards and weld leg height parameters for fillet welds and butt welds, and controlling the welding quality with a non-destructive testing pass rate of ≥98%, and then performing precise temperature and time annealing after welding, residual welding stress is effectively eliminated, cracks are prevented, and the connection strength and stability between the base 4 and the transmission cylinder 2 are significantly improved. This avoids component failure caused by welding defects during operation and ensures the long-term reliable operation of the drum 1.

[0029] S9. Restore the dismantled transmission chain tooth 5 and end water guide flange 6, with an assembly gap ≤1mm. The transmission chain tooth 5 includes a web plate 501; several teeth 502 are fixedly installed on the web plate 501; the web plate 501 is fixedly installed on the transmission cylinder 2 by bolt assembly, and the positioning deviation is <1mm. By adding a web plate 501 to strengthen the structural strength of the transmission chain tooth 5, and using a bolt assembly fixing method, it not only achieves quick disassembly and assembly and convenient subsequent maintenance, but also ensures the accuracy and stability of transmission meshing through high-precision positioning of <1mm, effectively reducing the impact load and wear during transmission, extending the service life of the transmission chain tooth 5 and the drum 1 as a whole, and further improving the reliability of the drum 1 operation.

[0030] By systematically addressing the pain points of traditional drum 1 maintenance, such as non-standard disassembly, low positioning accuracy, concentrated welding stress, and disordered maintenance process, through standardized steps including horizontal calibration of drum 1, precise dimensional measurement, controlled disassembly and grinding, load-adaptive beveling, overall assembly and benchmark positioning, welding process, and standardized assembly, this approach precisely solves the problems of non-standard disassembly, low positioning accuracy, concentrated welding stress, and disordered maintenance process. It achieves efficient and precise replacement of rail 3 and base 4, avoiding the waste of resources and high costs caused by the overall scrapping of drum 1 due to damage to local components. It also significantly improves the assembly accuracy and operational stability of drum 1 after maintenance, extends the service life of the equipment, shortens the maintenance period, and ensures the continuous and stable operation of the blast furnace slag treatment system.

[0031] The process also includes replacing the screen and frame 102 of the rotating drum 1: Replace the deformed and damaged fixing base 101 of the frame 102 with Q235B or Q355B material. The fixing base 101 should be 12-16mm thick, and the welding current should be 160-200A. The weld height of the fixing base 101 should be 8-12mm. After the screen is positioned and installed, its flatness should be ≤2mm / m, flat and without twisting, and its left-right deviation should be ≤1mm. The screen uses trapezoidal cross-section wire with a mesh gap of 0.8mm. All screen fixing bolts and embedded nuts should be replaced and welded securely, with the weld height matching the thickness of the connecting parts. By using compatible materials and precise parameters to reinforce the fixing base 101 of the screen frame 102, coupled with high-standard installation precision control of the screen, the structural load-bearing strength and stability of the screen frame 102 are enhanced, while ensuring the screen is flat and free of segregation. This improves the dewatering and slag removal efficiency of the rotary drum 1, avoids malfunctions caused by loose or deformed components, extends the service life of the screen and screen frame 102, and further guarantees the overall operational reliability of the rotary drum 1. The screen uses trapezoidal cross-section wires with a precise 0.8mm mesh gap, which not only improves the structural strength and anti-clogging ability of the wires and ensures the accuracy of dewatering and slag removal, but also prevents the screen from loosening or shifting by replacing all fasteners and achieving a firm weld with matching weld thickness to the connecting parts, extending the screen's service life and further guaranteeing the slag separation efficiency and operational stability of the rotary drum 1.

[0032] The process also includes the replacement steps for the diversion plate 7: the weld spacing of the diversion plate 7 is 100-150mm, the weld height is 3-5mm, there are no incomplete welds or slag inclusions, and the weld appearance fullness is ≥95%. By precisely controlling the weld spacing and weld height of the diversion plate, combined with the weld quality requirements of no incomplete welds, no slag inclusions, and high fullness, it is ensured that the diversion plate is installed firmly and reliably, without the risk of loosening or falling off, ensuring smooth and orderly slag and water diversion, improving the dewatering and slag removal efficiency of the drum 1, while extending the service life of the diversion plate, and further enhancing the operational stability of the drum 1.

[0033] After assembly, drum 1 undergoes heavy-duty anti-corrosion treatment: a modified polymeric wear-resistant and anti-corrosion coating (hardness ≥ HRC50) is applied. Before application, rust is removed to Sa2.5 grade using manual tools and an electric angle grinder (speed 8000-10000 r / min). The dry film thickness of the coating is 200-300 μm. The ambient temperature during application is 5-35℃, the relative humidity is ≤85%, and the coating adhesion is ≥5MPa. Through high-standard rust removal pretreatment, the selection of a high-hardness modified polymeric wear-resistant and anti-corrosion coating, and precise control of coating thickness, application environment, and adhesion, the wear resistance and anti-corrosion performance of drum 1 are significantly improved. This effectively resists corrosion and wear in operating conditions, prevents coating peeling and failure, extends the overall service life of drum 1, and ensures its long-term stable operation under harsh conditions.

[0034] This blast furnace slag treatment drum repair method is based on the horizontal calibration (levelness ≤ 1mm) and accurate measurement of the original dimensions of drum 1, establishing a unified spatial reference system to provide precise reference for subsequent component replacement; by standardizing the dismantling process (controlling the flatness of the cut surface) and pretreatment standards (rust removal grade Sa2.5, roughness Ra≤6.3μm), residual damage and impurities from old components are eliminated, ensuring the fit of new components; for the welding requirements of base 4, bevel parameters are designed according to the load of drum 1 and the thickness of base 4 to ensure that the welding penetration meets the standards and strengthens the connection strength; using rail 3 and The base 4 is a complete set, equipped with axial / radial dual references (end face of transmission cylinder 2 + outer circular surface) and a combination of high-precision measuring tools to achieve millimeter-level positioning accuracy and ensure balanced force distribution during the operation of drum 1. Through full-process stress control including preheating, symmetrical welding, post-weld annealing and heat preservation, welding cracks and residual stress accumulation are avoided. Combined with structural optimization and precise assembly of key components (transmission chain teeth 5, screen, and diversion plate), functional reliability is improved. Finally, a wear-resistant and corrosion-resistant barrier is constructed with high-standard heavy-duty anti-corrosion treatment, adapting to the harsh working conditions of blast furnace slag treatment and achieving long-term stable operation of drum 1 after repair and reuse.

[0035] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for maintaining a rotary drum used in blast furnace slag treatment, characterized in that, Includes the following steps: S1. Place the drum (1) horizontally and adjust the levelness to ≤1mm. Verify the levelness by using a level instrument to measure ≥4 evenly distributed measuring points on the outer surface of the transmission cylinder (2). S2. Measure and calibrate the installation fit dimensions of the old track (3), base (4), and transmission cylinder (2), including but not limited to the distance L1 (10000-12000mm) between the two ends of the drum (1) and the distance L2 (9000-10000mm) between the track (3) at both ends of the drum (1). S3. Use carbon arc gouging to cut and remove the old track (3) and its base (4), and the flatness deviation of the cut surface is ≤2mm; remove the transmission chain teeth (5) and the end water guide flange (6) that hinder the installation. S4. Grind and finish the mounting surface of the cutting part and the outer surface of the transmission cylinder (2) with a grinding wheel and / or a polishing machine; S5. A welding bevel (8) adapted to the transmission cylinder (2) is machined on the inner circular surface of the new base (4). When the drum transmission load is ≤50t, the bevel angle α is 30°-45° and the depth h is 3-7mm; when the load is >50t, the bevel angle α is 45°-60° and the depth h is 7-10mm. S6. Pre-assemble the new track (3) onto the base (4) according to the working conditions. The assembly gap is ≤0.5mm. Then, put the base (4) and the track (3) together from both ends of the transmission cylinder (2) into the fixed position. Avoid collision with the surface of the transmission cylinder (2) during the assembly process. S7. Using the end faces of the transmission cylinders (2) at both ends of the drum (1) as the axial reference and the outer circular surface as the radial reference, position and align according to the original data measured in step S2. The axial dimension accuracy is ≤2mm and the radial dimension accuracy is ≤1mm. Use ≥4 measuring points for verification. S8. Preheat the welding area to 100-150℃ before welding, use ≥6 points for symmetrical welding, and keep the temperature at 200-300℃ after welding for 2-4 hours to reduce welding stress. S9. Restore the dismantled transmission chain teeth (5) and end water guide flanges (6), with an assembly gap ≤1mm.

2. The method for maintaining a rotary drum for blast furnace slag treatment according to claim 1, characterized in that, The transmission chain teeth (5) in step S9 include a web plate (501); several teeth (502) are fixedly arranged on the web plate (501); the web plate (501) is fixedly installed on the transmission cylinder (2) by bolt group, and the positioning deviation is <1mm.

3. The method for maintaining a rotary drum for blast furnace slag treatment according to claim 1, characterized in that, In step S7, axial positioning is achieved by using a 3m long aluminum alloy straightedge (straightness ≤0.1mm / m) to fit against the side of the track (2), and a 15m steel tape measure (accuracy ≤0.5mm) for measurement and verification; radial positioning is achieved by calibrating ≥6 evenly distributed marker points with a DS05 level instrument, and by using a 0-level right angle ruler (accuracy ≤0.02mm / m) + steel tape measure for bidirectional measurement and verification to ensure that the positioning data deviation is ≤0.5mm.

4. The method for maintaining a rotary drum for blast furnace slag treatment according to claim 1, characterized in that, In step S8, the fillet weld is of grade CK with a weld leg height of 6-10mm, and the butt weld is of grade CS with a non-destructive testing pass rate of ≥98%. After welding, the weld is annealed at 550-650℃ to eliminate residual stress, and the holding time is 1-2h.

5. The method for maintaining a rotary drum for blast furnace slag treatment according to claim 1, characterized in that, The base (4) is machined with bevels on both outer sides along the axis. The bevel blunt edge size is 1-3mm. When the thickness of the base (4) is 16-20mm, the bevel depth is 5-8mm; when the thickness is 20-25mm, the bevel depth is 8-12mm, ensuring that the welding penetration is ≥ 2 / 3 of the thickness of the base (4).

6. The method for maintaining a rotary drum for blast furnace slag treatment according to claim 1, characterized in that, In step S4, the outer surface of the transmission cylinder (2) after grinding reaches the rust removal grade of Sa2.5, the roughness of the installation surface of the cutting part Ra≤6.3μm, the surface is free of oxide scale, spatter and dents, and the dent depth ≤0.5mm and area ≤5cm².

7. The method for maintaining a rotary drum for blast furnace slag treatment according to claim 1, characterized in that, It also includes the following steps for replacing the drum (1), screen and screen frame (102): Use Q235B or Q355B material to replace the fixed seat (101) of the deformed and damaged screen frame (102). The thickness of the fixed seat (101) is 12-16mm. The welding current is 160-200A when welding and strengthening. The weld height of the fixed seat (101) is 8-12mm. After the screen is positioned and installed, the flatness is ≤2mm / m, flat and without twisting, and the left and right deviation is ≤1mm.

8. The method for maintaining a rotary drum for blast furnace slag treatment according to claim 7, characterized in that, The screen uses trapezoidal cross-section wire with a mesh gap of 0.8mm. All screen fixing bolts and embedded nuts have been replaced and welded securely, and the weld height matches the thickness of the connecting parts.

9. The method for maintaining a rotary drum for blast furnace slag treatment according to claim 1, characterized in that, It also includes the replacement steps of the diversion plate (7): the spacing between the welding points of the diversion plate (7) is 100-150mm, the height of the weld is 3-5mm, there is no false welding or slag inclusion, and the fullness of the weld appearance is ≥95%.

10. The method for maintaining a rotary drum for blast furnace slag treatment according to claim 1, characterized in that, After assembly, the drum (1) is subjected to heavy anti-corrosion treatment: a modified polymer wear-resistant anti-corrosion coating (hardness ≥ HRC50) is used. Before construction, the rust is removed to Sa2.5 level by manual tools + electric angle grinder (speed 8000-10000r / min). The dry film thickness of the coating is 200-300μm. The construction environment temperature is 5-35℃, the relative humidity is ≤85%, and the coating adhesion is ≥5MPa.

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