Method for repairing abraded middle disc of pellet high-temperature fan

Abstract

The invention discloses a method for repairing abraded middle discs of a pellet high-temperature fan. The method comprises the following steps: firstly, identifying the abraded parts of the middle discs, performing annular cutting by adopting gas cutting, cutting off the abraded parts of the middle discs to separate the middle discs, defining the parts of the middle discs connected to a main shaft as first reserved middle discs, and defining the parts of the middle discs connected with blades as second reserved middle discs; a numerical control machine tool is adopted for machining the outer circumferential face of the first reserved middle disc and the inner circumferential face of the second reserved middle disc, and an annular repairing middle disc is manufactured according to the outer diameter size of the first reserved middle disc and the inner diameter size of the second reserved middle disc; then the repairing middle disc is fixedly welded to the first reserved middle disc and the second reserved middle disc; after welding, flaw detection treatment is conducted on a weld joint; if the welding seam meets the requirement, repairing of the middle disc is completed. The abraded part of the middle disc is replaced in a replacement and repair mode, the repaired middle disc meets the requirement and is high in reliability, and compared with a traditional mode of replacing the whole impeller, the replacement and maintenance cost is greatly reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of pellet production, and in particular relates to a method for repairing a worn middle disk of a pellet high-temperature fan on a pellet production line. Background Art

[0002] On the pelletizing production line of steel enterprises, the working temperature of the pelletizing high-temperature fan in the PHII section of the pelletizing reaches 410±20℃ during production operation. A high-temperature multi-tube dust collector is used for dust removal. Due to the inherent properties of the multi-tube dust collector, its dust removal efficiency is between 80-90%. During the production process, the residual high-temperature dust will cause wear on the impeller on the fan rotor, especially the middle disk of the impeller, which is more seriously worn during use. At present, users of high-temperature and large fans in the industry can only perform surfacing welding on both sides to restore the thickness after the middle disk of the fan impeller is worn. A large amount of surfacing welding will cause uncontrollable deformation, and there will be a large amount of welding stress. In actual use, the repair part of the middle disk will easily crack, causing an impeller runaway accident. Due to the lack of reliable repair technology, the impeller can only be scrapped as a whole and a new impeller must be customized, which has high replacement costs. Summary of the invention

[0003] The object of the present invention is to provide a method for repairing the wear of the middle disk of a pelletizing high-temperature fan with high reliability and low repair cost.

[0004] The object of the present invention is achieved through the following technical solution: A method for repairing the wear of the middle disk of a pelletizing high-temperature fan, characterized in that it comprises the following steps: S1: Identify the worn part of the middle disk of the impeller, use the outer ring of the impeller to center, mark the annular cutting area on the middle disk, and make the worn part of the middle disk located in the annular cutting area; S2: using gas cutting to cut off the annular cutting area and separate the middle disk, wherein the middle disk portion connected to the main shaft is defined as the first reserved middle disk, and the middle disk portion connected to the blades is defined as the second reserved middle disk; S3: using a numerical control machine tool to process the outer circumference of the first reserved center disk and the inner circumference of the second reserved center disk respectively, and recording the outer diameter of the first reserved center disk and the inner diameter of the second reserved center disk after processing; S4: manufacturing a ring-shaped repaired middle disk according to the outer diameter size of the first reserved middle disk and the inner diameter size of the second reserved middle disk; S5: First, put the repaired middle plate onto the first reserved middle plate, use argon arc welding to prime and position, and then weld and fix the two by symmetrical staggered welding; S6: Put the second reserved middle plate onto the repaired middle plate, first use argon arc welding to prime and position, and then weld and fix the two by symmetrical staggered welding; S7: After welding, the weld is inspected for flaws; if the weld meets the requirements, the wear of the middle disk of the pelletizing high-temperature fan is repaired; if there are problems with the weld, it is reworked and repaired until the weld meets the requirements.

[0005] Furthermore, a first wear-resistant plate is welded at a welding point between the repaired center disk and the first retained center disk, and a second wear-resistant plate is welded at a welding point between the repaired center disk and the second retained center disk.

[0006] Furthermore, the welding position corresponding to the repaired center disc is provided with welding and centering inclined surfaces.

[0007] The beneficial effects of the present invention are: by adopting the scheme of the present invention, the worn part of the middle disk is replaced by replacement and repair. The repaired middle disk meets the requirements and has high reliability. Compared with the traditional method of replacing the entire impeller, the replacement and maintenance costs are greatly reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The present invention is further described using the accompanying drawings, but the embodiments in the accompanying drawings do not constitute any limitation to the present invention. A person skilled in the art can obtain other drawings based on the following drawings without creative work.

[0009] Figure 1 It is a schematic diagram of the structure of the pelletizing high temperature fan rotor.

[0010] Figure 2 It is a structural schematic diagram of the repairing middle disk in the present invention.

[0011] Figure 3 yes Figure 2 Enlarged schematic diagram of part A.

[0012] Figure 4 It is a schematic diagram of the structure of the repaired center disc mounted on the rotor main shaft.

[0013] Figure 5 yes Figure 4 Schematic diagram of the enlarged portion B. DETAILED DESCRIPTION

[0014] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that the embodiments of the present application and the features therein can be combined with each other without conflict.

[0015] The present invention reduces the cost of replacing the entire impeller to the greatest extent by partially replacing the worn center disk of the fan. The repair method for the worn center disk of the high-temperature fan is as follows.

[0016] Step 1: Identify the worn portion of the middle disc of the impeller, use the outer ring of the impeller to center, mark the annular cutting area on the middle disc so that the worn portion of the middle disc is located within the annular cutting area.

[0017] The second step: use gas cutting to cut off the annular cutting area and separate the middle disk, wherein the middle disk part connected to the main shaft 100 is defined as the first retained middle disk 10, and the middle disk part connected to the blades is defined as the second retained middle disk 20; the middle disk part corresponding to the annular cutting area is treated as scrap.

[0018] Step 3: Use a CNC machine tool to process the outer circumference of the first reserved center plate 10 and the inner circumference of the second reserved center plate 20 respectively, and record the outer diameter d of the first reserved center plate 10 after processing. 1 and the inner diameter d of the second retaining center disk 20 2 .

[0019] Step 4: According to the outer diameter of the first reserved center plate and the inner diameter of the second reserved center plate, a ring-shaped repair center plate 30 is manufactured. The inner diameter of the repair center plate 30 is d 3 , d 1 ≤d 3 ≤d 1 +2mm; the outer diameter of the repaired middle plate 30 is d 4 , d 2 -2mm≤d3≤d 2 A welding and centering slope 301 is provided on the repaired center disk to improve the centering accuracy and welding strength.

[0020] Step 5: First, put the repaired center plate 30 onto the first reserved center plate 10, first use argon arc welding to prime and position, and then use symmetrical staggered welding to weld and fix the two. Then put the second reserved center plate 20 onto the repaired center plate 30, first use argon arc welding to prime and position, and then use symmetrical staggered welding to weld and fix the two. Preferably, the first wear-resistant plate 40 is welded at the welding point between the repaired center plate 30 and the first reserved center plate 10, and the second wear-resistant plate 50 is welded at the welding point between the repaired center plate 30 and the second reserved center plate 20. The first wear-resistant plate 40 and the second wear-resistant plate 50 are used to connect and strengthen, improve strength, and enhance wear resistance.

[0021] Specific welding operation requirements are: 1. Before welding, clean the oil, dust and rust on the groove and nearby areas to keep the welding surface clean.

[0022] 2. Use argon arc welding to prime and weld both sides to ensure full penetration without pores or cracks; the welding material is TIG-50 welding wire with a diameter of 2.4mm.

[0023] 3. Fill and cover the surface with carbon dioxide gas shielded welding to ensure there are no pores, slag inclusions and cracks; the welding material is Atlantic CHT711 flux-cored welding wire with a diameter of 1.2mm.

[0024] 4. Weld both sides in time to prevent deformation.

[0025] Step 6: After welding, perform flaw detection on the weld; if the weld meets the requirements, the repair of the wear of the middle disk of the pelletizing high-temperature fan is completed; if there are problems with the weld, rework and repair it until the weld meets the requirements.

[0026] The method of the present invention was used to repair the middle disk of a high-temperature heat recovery fan of a pelletizing unit in a steel plant. The cost was 15% of replacing the entire impeller. After 24 months of use, flaw detection did not reveal defects such as cracks and severe wear. In addition, indicators such as vibration were stable during use, with high reliability.

[0027] In summary, although the present invention lists the above-mentioned preferred embodiments, it should be noted that although technicians in this field can make various changes and modifications, unless such changes and modifications deviate from the scope of the present invention, they should be included in the protection scope of the present invention.

Claims

1. A method for repairing the wear of the middle disk of a pelletizing high-temperature fan, characterized in that: The steps include: S1: Identify the worn part of the middle disk of the impeller, use the outer ring of the impeller to center, mark the annular cutting area on the middle disk, and make the worn part of the middle disk located in the annular cutting area; S2: using gas cutting to cut off the annular cutting area and separate the middle disk, wherein the middle disk portion connected to the main shaft is defined as the first reserved middle disk, and the middle disk portion connected to the blades is defined as the second reserved middle disk; S3: using a numerical control machine tool to process the outer circumference of the first reserved center disk and the inner circumference of the second reserved center disk respectively, and recording the outer diameter of the first reserved center disk and the inner diameter of the second reserved center disk after processing; S4: manufacturing a ring-shaped repaired middle disk according to the outer diameter size of the first reserved middle disk and the inner diameter size of the second reserved middle disk; S5: First, put the repaired middle plate onto the first reserved middle plate, use argon arc welding to prime and position, and then weld and fix the two by symmetrical staggered welding; S6: Put the second reserved middle plate onto the repaired middle plate, first use argon arc welding to prime and position, and then weld and fix the two by symmetrical staggered welding; S7: After welding, the weld is inspected for flaws; if the weld meets the requirements, the wear of the middle disk of the pelletizing high-temperature fan is repaired; if there are problems with the weld, it is reworked and repaired until the weld meets the requirements.

2. The method for repairing the wear of the middle disk of the pelletizing high-temperature fan according to claim 1 is characterized in that: A first wear-resistant plate is welded at a welding point between the repaired center plate and the first retained center plate, and a second wear-resistant plate is welded at a welding point between the repaired center plate and the second retained center plate.

3. The method for repairing the wear of the middle disk of the pelletizing high temperature fan according to claim 1 or 2, characterized in that: The welding position corresponding to the repaired center plate is provided with welding and centering inclined surfaces.

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