Repair method for local cylinder shrinkage of middle cylinder of hydraulic stand column

Abstract

The invention relates to the technical field of machining, in particular to a repairing method for local cylinder shrinkage of a middle cylinder of a hydraulic stand column, and mainly solves the technical problems that the cost is increased and the construction period is delayed in a product scrapping treatment mode when an existing middle cylinder of the hydraulic stand column has machining defects. The repairing method for local cylinder shrinkage of the middle cylinder of the hydraulic stand column comprises the steps that S1, the cylinder barrel wall thickness and the cylinder barrel outer wall material of the cylinder shrinkage part of a product are determined; s2, layered girth welding is conducted on the outer wall of the cylinder barrel corresponding to the cylinder shrinkage part of the product through a surfacing welding technology, and the number of layers of layered girth welding is determined according to the target shrinkage amount of the inner wall of the cylinder barrel; s3, cooling; s4, detecting the size of the inner wall of the cylinder barrel at the cylinder shrinkage part of the product; and S5, the inner wall and the outer wall of the cylinder barrel are machined till the size requirement of a finished product is met. Compared with an existing scrap treatment mode, the method has the advantages that the raw material cost, the equipment cost and the labor cost can be saved, meanwhile, the repairing time is far shorter than that of re-feeding processing, and therefore the construction period can be guaranteed.

Description

Technical Field

[0001] The invention relates to the technical field of mechanical processing, and in particular to a method for repairing a partially shrunken cylinder of a hydraulic column. Background Art

[0002] When finishing the stopper of the hydraulic column cylinder, due to tool wear, chipping, processing program errors, etc., the diameter of the stopper sealing surface and the thread minor diameter surface will be larger than the finished product size. For example, Figure 1 The following is a standard dimension drawing of a product. Figure 2 This is the dimensional drawing when processing defects occur. The comparison shows that when processing defects occur, the product size will exceed the tolerance range allowed by the drawing.

[0003] Since the threaded surface cannot be welded, in the prior art, such products are scrapped and re-processed. However, re-processing will increase the cost of raw materials, equipment and labor, and it is easy to delay the construction period, making it difficult to meet actual production needs. Summary of the invention

[0004] In order to overcome the technical defects of increased cost and delayed construction period in the existing method of scrapping the product when processing defects occur in the middle cylinder of a hydraulic column, the present invention provides a method for repairing a partially shrunken middle cylinder of a hydraulic column.

[0005] The method for repairing a partially shrunken cylinder of a hydraulic column provided by the present invention comprises the following steps in sequence: S1. Confirm the cylinder wall thickness of the shrinking part of the product, and use the outer wall of the cylinder as the first judgment standard to make the inner wall shrink. If the first judgment standard is not met, turn the outer wall of the cylinder until the first judgment standard is met; Confirm the outer wall material of the cylinder at the shrinkage part of the product, and take the outer wall material of the cylinder as the second judgment standard whether it affects the welding performance. If the second judgment standard is not met, remove the outer wall material of the cylinder; When the product satisfies both the first judgment standard and the second judgment standard, proceed to step S2; S2. Use surfacing technology to perform layered girth welding on the outer wall of the cylinder corresponding to the shrinkage position of the product. The number of layers of layered girth welding is determined according to the target shrinkage amount of the inner wall of the cylinder; S3. Cooling; S4. Detect the inner wall size of the cylinder where the product shrinks: If the process size requirements are not met, repeat steps S2 to S3 until the process size requirements are met; if the process requirements are met, proceed directly to step S5; S5. Machine the inner and outer walls of the cylinder until the finished product size requirements are met.

[0006] Optionally, in step S2, a small current of 200A-250A is used for the first layer of ring welding to perform limiting welding at both axial ends of the outer wall of the cylinder corresponding to the cylinder shrinkage part of the product, and a large current of 300A-350A is used for welding the remaining layers in the area formed by the first layer of ring welding.

[0007] Optionally, one end of the outer wall of the cylinder barrel corresponding to the product cylinder shrinkage portion is aligned with the product end surface, and the other end extends to the axial inner side of the product cylinder shrinkage portion.

[0008] Optionally, the remaining layers are welded in sections from the end face of the product inward along the axial direction.

[0009] Optionally, adjacent segments are overlaid with connections.

[0010] Optionally, a surface treatment step is provided between step S4 and step S5, wherein the surface treatment step is used to process the surface structure of the outer wall of the cylinder.

[0011] Optionally, the surface structure of the outer wall of the cylinder is a cladding layer, and the surface treatment step includes: 1) Turn the outer wall of the cylinder to the size before cladding; 2) Cladding the outer cylindrical surface of the cylinder to the process size.

[0012] Optionally, step S5 includes: S51. Finish turning the outer wall of the cylinder corresponding to the shrinkage part of the product to the grinding size; S52. Fine-tune the inner wall of the cylinder at the shrinkage position of the product to the finished product size; S53. Check the inner wall size of the rest of the product: if it meets the finished product size requirements, no processing is done; if the inner hole shrinkage does not meet the finished product size requirements, honing is done to the finished product size; S54. The outer wall of the cylinder corresponding to the shrinking part of the polished product is kept consistent with the outer diameter of the unshrinking section; S55. Grind the outer circle of the product as a whole and ensure that the outer circle size after grinding is within the range of the size tolerance required by the drawing.

[0013] The technical solution provided by the present invention has the following advantages compared with the prior art: The method for repairing a partially shrunken cylinder in a hydraulic column provided by the present invention is to repair the processing defect by surfacing welding on the outer wall of the cylinder to shrink the inner wall of the cylinder. Compared with the existing scrapping treatment method, this method can save raw material costs, equipment costs and labor costs. At the same time, the time taken for repair is much shorter than re-feeding and processing, so the construction period can also be guaranteed. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0015] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0016] Figure 1 A diagram showing the standard dimensions of the corresponding products in the embodiments of the present invention; Figure 2 A dimensional diagram showing a corresponding product in an embodiment of the present invention when a processing defect occurs; Figure 3 A schematic diagram of a ring welding layout in an embodiment of the present invention is shown; Figure 4 Schematic diagram of the ring welding structure in an embodiment of the present invention. DETAILED DESCRIPTION

[0017] In order to more clearly understand the above-mentioned objectives, features and advantages of the present invention, the scheme of the present invention will be further described below. It should be noted that the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

[0018] In the description, it should be noted that the terms "first" and "second" are only used for descriptive purposes and should not be understood as indicating or implying relative importance. It should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be internal communication between two elements. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0019] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein; it is obvious that the embodiments in the specification are only part of the embodiments of the present invention, rather than all of the embodiments.

[0020] The specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0021] Reference Figures 1 to 4 This embodiment provides a method for repairing a partially shrunken cylinder of a hydraulic column, including steps S1 to S5. The following is a specific description of a cladding cylinder with an inner wall rolling surface diameter of Φ200 mm and a sealing surface and a thread minor diameter surface that are 0.8 mm larger.

[0022] S1. Confirm the cylinder wall thickness of the product's cylinder shrinkage area, and use the first judgment standard that the outer wall of the cylinder can shrink the inner wall due to surfacing welding. If the first judgment standard is not met, turn the outer wall of the cylinder until it meets the first judgment standard; confirm the outer wall material of the cylinder at the product's cylinder shrinkage area, and use the second judgment standard that the outer wall material of the cylinder does not affect the welding performance. If the second judgment standard is not met, remove the outer wall material of the cylinder; when the product meets both the first judgment standard and the second judgment standard, proceed to step S2.

[0023] Specifically, the wall thickness of the shrinkage part of the middle cylinder is relatively thick, which does not meet the first judgment standard; the outer wall of the middle cylinder is provided with a cladding layer, which does not meet the second judgment standard. Therefore, it is necessary to machine away the cladding layer and part of the wall thickness at the stop of the outer wall of the cylinder until the radial dimension is 4mm smaller than the finished product dimension, so as to meet both the first and second judgment standards.

[0024] Specifically, one end of the outer wall of the cylinder corresponding to the shrinking part of the product is aligned with the end face of the product, and the other end extends to the axial inner side of the shrinking part of the product. During operation, the axial length of the turning part of the outer wall of the cylinder is about 30mm longer than the stop, so as to ensure that the inner wall of the entire stop can shrink under the action of the outer wall surfacing.

[0025] S2. Use surfacing technology to perform layered circumferential welding on the outer wall of the cylinder corresponding to the shrinkage position of the product. The number of layers of layered circumferential welding is determined according to the target shrinkage amount of the inner wall of the cylinder.

[0026] Specifically, in step S2, a small current of 200A-250A is used for the first layer of ring welding to perform limiting welding at both axial ends of the cylinder outer wall corresponding to the cylinder shrinkage part of the product, and a large current of 300A-350A is used for welding the remaining layers in the area formed by the first layer of ring welding.

[0027] It should be noted that the first layer mainly plays a limiting role, limiting the welding range of the remaining layers. The purpose of using small current welding for the first layer is to prevent defects such as black lines and pores at the joints; and the purpose of using high current welding for the remaining layers is to ensure the shrinkage amount.

[0028] It is easy to understand that the shrinkage of the cylinder is closely related to the current size during the ring welding and the number of ring welding layers. In this embodiment, for a shrinkage of 0.8 mm, three layers are welded, the first layer is welded with a current of 20V and 200A, and the second and third layers are welded with a current of 30V and 310A.

[0029] Specifically, the remaining layers are welded inwardly in sections along the axial direction from the end surface of the product. In this embodiment, the second layer and the third layer are welded in three sections.

[0030] More specifically, adjacent sections are connected in a covering manner, that is, after the first section is welded, the second section is not only aligned with the first section, but the junction between the second section and the first section covers part of the first section to avoid gaps at the junction of adjacent sections that affect the continuity of the inner wall shrinkage.

[0031] S3. Cooling.

[0032] It is easy to understand, just cool to room temperature.

[0033] S4. Detect the inner wall size of the cylinder at the shrinkage part of the product: if it does not meet the process size requirements, repeat steps S2 to S3 until the process size requirements are met; if it meets the process requirements, proceed directly to step S5.

[0034] It should be noted that meeting the process size requirements means meeting the processing allowance in the drawing. In this embodiment, the allowance is about 0.3 mm.

[0035] S5. Machine the inner and outer walls of the cylinder until the finished product size requirements are met.

[0036] Specifically, step S5 includes: S51. Fine turning the outer wall of the cylinder corresponding to the shrinking part of the product to the grinding size, the grinding size of this embodiment is Φ260.2mm; S52. Finely trimming the inner wall of the cylinder at the shrinking part of the product to the finished product size, such as Figure 1 As shown; S53. Check the inner wall size of the rest of the product, especially the part adjacent to the surfacing outer wall: if it meets the finished product size requirements, no treatment is done; if the inner hole shrinkage does not meet the finished product size requirements, honing to the finished product size, such as Figure 1 As shown; S54. Grind and polish the outer wall of the cylinder corresponding to the shrinking part of the product, and keep it consistent with the outer diameter of the unshrinking section; S55. Grind the outer diameter of the product as a whole and ensure that the outer diameter after grinding is within the range of the size tolerance requirements of the drawing to ensure that the roughness of the connection area meets the requirements of the drawing, and the outer diameter roughness of the finished product size cladding section is ≤0.4, such as Figure 1 shown.

[0037] Furthermore, a surface treatment step is provided between step S4 and step S5, and the surface treatment step is used to process the surface structure of the outer wall of the cylinder. In this embodiment, the surface structure of the outer wall of the cylinder is a cladding layer, and the surface treatment step includes: 1) Turn the outer wall of the cylinder to the size before cladding, φ259mm; 2) Cladding the outer cylindrical surface of the cylinder to the process size, φ261.5mm.

[0038] Compared with the prior art, the method for repairing the partial shrinkage of the cylinder in the hydraulic column of this embodiment has the following advantages: a. The problem of the inner wall being too large has been solved. The size and performance of the inner wall after the repair fully meet the requirements of the drawings.

[0039] b. Save material costs. If the traditional scrapping method is used, serious waste of materials will occur. This repair method can greatly save material costs.

[0040] c. Save processing costs. Re-production not only requires materials, but also consumes a lot of manpower and equipment costs.

[0041] d. The delivery time can be guaranteed. Compared with the traditional scrapping and reprocessing, the processing cycle from raw materials to finished products is too long, ranging from about a week to about a month. The new solution only takes a few hours to repair.

[0042] e. Saves material space.

[0043] The above is only a specific implementation of the present invention, which enables those skilled in the art to understand or implement the present invention. Although detailed descriptions are given with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments, and they should all be covered by the protection scope of the claims.

Claims

1. A method for repairing a partially shrunken cylinder in a hydraulic column. It is characterized in that The steps are as follows: S1. Confirm the cylinder wall thickness of the shrinking part of the product, and use the outer wall of the cylinder as the first judgment standard to make the inner wall shrink. If the first judgment standard is not met, turn the outer wall of the cylinder until the first judgment standard is met; Confirm the outer wall material of the cylinder at the shrinkage part of the product, and take the outer wall material of the cylinder as the second judgment standard whether it affects the welding performance. If the second judgment standard is not met, remove the outer wall material of the cylinder; When the product satisfies both the first judgment standard and the second judgment standard, proceed to step S2; S2. Use surfacing technology to perform layered girth welding on the outer wall of the cylinder corresponding to the shrinkage position of the product. The number of layers of layered girth welding is determined according to the target shrinkage amount of the inner wall of the cylinder; S3. Cooling; S4. Detect the inner wall size of the cylinder where the product shrinks: If the process size requirements are not met, repeat steps S2 to S3 until the process size requirements are met; if the process requirements are met, proceed directly to step S5; S5. Machine the inner and outer walls of the cylinder until the finished product size requirements are met.

2. The method for repairing a partially shrunken cylinder of a hydraulic column according to claim 1, It is characterized in that In step S2, a small current of 200A-250A is used for the first layer of ring welding to perform limiting welding at both axial ends of the cylinder outer wall corresponding to the cylinder shrinkage part of the product, and a large current of 300A-350A is used for welding the remaining layers in the area formed by the first layer of ring welding.

3. The method for repairing a partially shrunken cylinder of a hydraulic column according to claim 2, It is characterized in that One end of the outer wall of the cylinder barrel corresponding to the product cylinder shrinkage position is aligned with the product end surface, and the other end extends to the axial inner side of the product cylinder shrinkage position.

4. The method for repairing a partially shrunken cylinder of a hydraulic column according to claim 3, It is characterized in that The remaining layers are welded in sections from the end face of the product inward along the axial direction.

5. The method for repairing a partially shrunken cylinder of a hydraulic column according to claim 4, It is characterized in that Adjacent segments are overlaid with connections.

6. The method for repairing a partially shrunken cylinder of a hydraulic column according to claim 1, It is characterized in that A surface treatment step is provided between step S4 and step S5, and the surface treatment step is used to process the surface structure of the outer wall of the cylinder.

7. The method for repairing a partially shrunken cylinder of a hydraulic column according to claim 6, It is characterized in that The surface structure of the outer wall of the cylinder is a cladding layer, and the surface treatment steps include: 1) Turn the outer wall of the cylinder to the size before cladding; 2) Cladding the outer cylindrical surface of the cylinder to the process size.

8. The method for repairing a partially shrunken cylinder of a hydraulic column according to any one of claims 1 to 7, It is characterized in that Step S5 includes: S51. Finish turning the outer wall of the cylinder corresponding to the shrinkage part of the product to the grinding size; S52. Fine-tune the inner wall of the cylinder at the shrinkage position of the product to the finished product size; S53. Check the inner wall size of the rest of the product: if it meets the finished product size requirements, no processing is done; if the inner hole shrinkage does not meet the finished product size requirements, honing is done to the finished product size; S54. The outer wall of the cylinder corresponding to the shrinking part of the polished product is kept consistent with the outer diameter of the unshrinking section; S55. Grind the outer circle of the product as a whole and ensure that the outer circle size after grinding is within the range of the size tolerance required by the drawing.

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