A processing method for ultra-large variable diameter ring

Abstract

This invention belongs to the field of large forging machining technology, specifically involving a machining method for an ultra-large diameter replacement ring. The specific steps include: (1) aligning the workpiece; (2) setting the outer diameter baseline of the small end of the workpiece; setting two workpiece height baselines as upper and lower baselines, with a vertical distance of 10mm between the upper and lower baselines; (3) semi-finishing the small end plane, outer diameter, and R-arc surface, observing the oxide scale after heat treatment, and removing all oxide scale by pressing down the upper and lower baselines to obtain the final height baseline; (4) semi-finishing the inner diameter; (5) finishing the outer diameter of the large end; (6) flipping the workpiece, using the small end plane as a reference, finishing the large end plane and the remaining outer diameter portion of the large end of the chuck; (7) finishing the inner diameter. This ultra-large diameter replacement ring achieves equal wall thickness machining of the large and small ends while ensuring high-precision dimensional and geometric tolerances; and has a short cycle time and high efficiency.

Description

Technical Field

[0001] This invention belongs to the field of large forging machining technology, specifically relating to a machining method for an ultra-large diameter replacement ring. Background Technology

[0002] Marine hydraulic pile drivers are key equipment in offshore wind power, offshore platforms, bridges, and other marine engineering construction, and their application in construction is becoming increasingly widespread. Fully hydraulic pile drivers that have been developed and applied possess both high operational quality and high efficiency. With the rapid development of offshore wind power, the demand for marine hydraulic pile drivers is experiencing explosive growth. Large forgings used in pile drivers, such as the hammering ring, are large, irregularly shaped ring forgings and are crucial force transmission components for transferring the hammering force to large single-column piles. Their design life is generally 200 piles. Pile drivers operate at a penetration speed of 6 mm and a striking frequency of 24-30 sppm, and must withstand significant alternating impact loads during use. Currently, the manufacturing of such large forgings requires a processing cycle of nearly 8 months from smelting to finishing, with finishing taking approximately 25 days. Considering costs and other factors, the processing cycle may be even longer.

[0003] Therefore, in view of the above situation, it is necessary to provide a machining method for ultra-large diameter replacement rings to improve the machining accuracy and efficiency of ultra-large diameter replacement rings, and ensure assembly requirements and service under harsh working conditions. Summary of the Invention

[0004] To achieve the above objectives, this invention provides a method for machining ultra-large diameter replacement rings, specifically by precision machining of ultra-large diameter replacement ring forgings that have undergone performance heat treatment. This process not only completely removes the oxide scale covering the surface of the ultra-large diameter replacement ring forgings after performance heat treatment, but also further improves accuracy (dimensional tolerance ±1mm, form and position tolerance 0.8mm), shortens the precision machining cycle by approximately 10-16 days, and ensures quality while improving efficiency.

[0005] This invention employs a "net proximity" machining method to perform overall precision machining of ultra-large variable-diameter replacement rings. Since the performance heat treatment allowance is determined, the deformation of the workpiece during the process varies with its dimensions. Furthermore, because replacement ring forgings are large forgings with varying diameters and cross-sections, the surface areas of the upper and lower end faces are different. The performance requirements of such forgings are highly dependent on the amount of material removed from the upper and lower end faces. Therefore, this invention, based on the overall net proximity machining concept, shares similarities with hot forming. Implementing the "net proximity" machining process enables the overall precision machining of ultra-large variable-diameter replacement rings.

[0006] The present invention provides a method for processing an ultra-large diameter changing ring, comprising the following steps:

[0007] (1) Align the workpiece;

[0008] (2) Set the outer diameter baseline of the small end of the workpiece; set two workpiece height baselines as upper and lower baselines, with a vertical distance of 10mm between the upper and lower baselines.

[0009] (3) Semi-finish the small end plane, outer diameter and R arc surface, observe the oxide scale after the performance heat treatment, press down the upper and lower reference lines until all the oxide scale is removed, and obtain the reference line of the final height.

[0010] (4) Inner diameter of semi-finished workpiece;

[0011] (5) Finish machining of the outer diameter of the large end;

[0012] (6) Flip the workpiece over, and use the small end plane as a reference to finish machine the large end plane and the remaining outer diameter of the large end of the chuck.

[0013] (7) Finish the inner diameter.

[0014] Furthermore, the specific method for aligning the workpiece in step (1) is as follows:

[0015] Place the workpiece with the large end facing down and align it. Use a dial indicator to align the workpiece with the outer diameter of the large end and the outer diameter of the small end. Control the dial indicator head clearance error within the range of 0-5mm and calibrate the center of the workpiece.

[0016] The specific method for step (2) is as follows:

[0017] Set a reference line for the outer diameter of the small end of the workpiece, and machine a reference circle on the outer diameter of the small end of the workpiece as the reference line for the outer diameter of the small end; set two reference lines for the height of the workpiece, and machine a 0.5mm deep groove on the outer diameter of the small end as the lower reference line position of the Z coordinate origin; 10mm above the lower reference line, machine a 0.5mm deep groove on the outer diameter of the small end as the upper reference line position of the Z coordinate origin.

[0018] The specific method for step (3) is as follows:

[0019] Set the baseline Z=0 on the Z-axis zero point. Move the X-axis zero point 10mm inward from the outer diameter of the small end as the reference point. Program the CNC vertical lathe and semi-finish the small end plane, outer diameter, and R-curve surface. Observe the oxide scale on the workpiece. After each pass, advance the X-axis by 4mm and continue to set the origin for machining. If oxide scale still exists during the process, continue to press down the upper and lower baselines and the baseline of the small end outer diameter until all oxide scale is removed.

[0020] The specific requirements for the inner diameter of the semi-finished workpiece in step (4) are: to machine the inner diameter of the workpiece with a 5mm allowance on one side and then flip the workpiece over.

[0021] In step (5) of finishing the outer diameter of the large end, the outer diameter of the large end is the outer diameter of the part above the large end chuck gripper.

[0022] The specific method for step (6) is as follows:

[0023] Position the flipped workpiece with the small end plane as the reference. Use a dial indicator to align the workpiece with the outer diameter of the large end until the error is less than 1mm. Finish machine the large end plane and clamp the remaining outer diameter of the large end. If there is still oxide scale on the large end plane, continue to press down the reference line by 2mm increments until all the oxide scale is removed.

[0024] The specific method for finishing the inner diameter of the workpiece in step (7) is as follows:

[0025] Two workpiece height reference lines are established. The lower reference line, located at the point where a 0.5mm deep groove is machined on the outer diameter of the larger end, serves as the Z-coordinate origin. The upper reference line, located 10mm above the lower reference line, is also machined on the outer diameter of the larger end. The workpiece's inner diameter is then finished. The lathe speed for final finishing is 2.4-3.2 rad / min, the feed rate is set to 0.5mm / min, and the depth of cut is set to 0.3-0.5mm, achieving a workpiece surface roughness of Ra3.2.

[0026] The technical effects that this invention can achieve are:

[0027] 1. Higher precision. This invention employs a "net proximity" machining method to perform overall precision machining on the ultra-large diameter replacement ring. The manufactured ultra-large diameter replacement ring forging not only achieves equal thickness machining of the outer diameter of the large end, the outer diameter of the small end, and the inner diameter, but also ensures machining accuracy reaching a dimensional tolerance of ±1mm and a form and position tolerance of 0.8mm. Compared with existing technologies, the dimensional tolerance is improved by about 1mm and the form and position tolerance by about 0.7mm, which is a significant improvement.

[0028] 2. Significantly shortens the finishing cycle. This invention only requires flipping the workpiece once, and the finishing time is 10-12 days, which is nearly 10-16 days shorter than the existing technology, resulting in a significant improvement in efficiency; moreover, the quality is guaranteed, with excellent surface quality and a surface roughness of only Ra3.2, which is far superior to existing technology products and comparative examples with a surface roughness > Ra4.2, providing strong technological support for future mass production;

[0029] 3. Reduced process costs. Because the precision machining of the ultra-large diameter changing ring of this invention is quick and the overall processing cost is low, it can save approximately 200,000 yuan compared to existing processes, demonstrating significant economic benefits. Attached Figure Description

[0030] Figure 1 A schematic diagram of the finished product of an ultra-large diameter replacement ring forging;

[0031] Figure 2 This is a drawing showing the allowance of the forged blank for the finished product of an ultra-large diameter replacement ring. Detailed Implementation

[0032] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand the present invention, but it is not intended to limit the present invention.

[0033] Example 1

[0034] A method for machining an ultra-large diameter ferrule forging includes the following steps:

[0035] S1 line

[0036] Place the workpiece on the platform, level it, draw a crosshair in the center of the workpiece, and draw the height position line of the workpiece.

[0037] The S2 uses a 10-meter CNC vertical lathe for precision machining of workpieces.

[0038] S2.1 Level the machine tool worktable and correct the verticality of the slide to ensure the machining accuracy of the machine tool;

[0039] S2.2 Place eight leveling shims on the vertical lathe turntable, place the workpiece with the large end facing down on the leveling shims, and use a dial indicator to align the workpiece multiple times.

[0040] The correction method is as follows:

[0041] Use a dial indicator to align the workpiece for both the large and small end outer diameters. Control the dial indicator head clearance error within the range of 0-5mm and calibrate the center of the workpiece to ensure uniform machining allowance and reduce the difficulty of subsequent machining.

[0042] Because the workpiece deforms irregularly after performance heat treatment, the original machining datum has disappeared. This invention involves multiple dial gauge measurements at different heights and positions to ensure uniform allowance.

[0043] S2.3 Set the outer diameter machining datum line of the workpiece, and at the same time set the upper and lower datum lines in the Z direction within a range of 10mm;

[0044] The method for setting a baseline is as follows:

[0045] Set a reference line for the outer diameter of the small end of the workpiece, and machine a reference circle on the outer diameter of the small end of the workpiece as the reference line for the outer diameter of the small end.

[0046] Two workpiece height reference lines are set as upper and lower reference lines, with a vertical distance of 10mm between them. The specific method is as follows:

[0047] A 0.5mm deep groove is machined on the outer diameter of the small end to serve as the baseline position below the Z-coordinate origin; 10mm above the lower baseline, a 0.5mm deep groove is machined on the outer diameter of the small end to serve as the upper baseline position above the Z-coordinate origin.

[0048] Because heat treatment can cause workpieces to expand or shrink, their dimensions may deviate from the original reference dimensions, and the allowances in each part will also change accordingly. Adjustments can only be made using theoretical allowances to determine the range of the reference line. This way, there is room for adjusting the allowances, and the risk of not being able to process the finished product due to adjusting the reference line can be avoided.

[0049] S2.4 Semi-finished small end plane, outer diameter and R arc surface, observe the oxide scale after performance heat treatment, and remove all oxide scale by pressing down the upper and lower reference lines to obtain the reference line of the final height;

[0050] The specific method is as follows:

[0051] Set the baseline at Z=0 on the Z-axis zero point. Move the X-axis zero point 10mm inward from the outer diameter of the small end as the reference point. Program the CNC vertical lathe. Semi-finish the small end plane, outer diameter, and R-curve surface, observing the oxide scale condition. After each pass, advance the X-axis 4mm and continue machining from the origin. If oxide scale remains, continue pressing down on the upper and lower baselines and the baseline of the small end's outer diameter until all oxide scale is removed. Measure the wall thickness and compare the measured data with the theoretical dimensions to ensure sufficient machining allowance for the finished product.

[0052] S2.5 precision machined large end outer diameter;

[0053] S2.6 Flip the workpiece, using the small end plane as a reference, and finish machine the large end plane and the remaining outer diameter of the large end of the chuck.

[0054] (1) Position the flipped workpiece with the small end plane as the reference, and use a dial indicator to align the workpiece with the outer diameter of the large end until the error is less than 1mm; set two workpiece height reference lines, and use the 0.5mm deep groove on the outer diameter of the large end as the reference line position under the Z coordinate origin.

[0055] (2) At a position 10mm above the lower baseline, machine a 0.5mm deep groove on the outer diameter of the large end to serve as the position of the upper baseline for the origin of the Z coordinate.

[0056] (3) Finish the large end plane and clamp the remaining large end outer diameter. If there is still oxide scale on the large end plane, continue to press down the reference line by 2mm. Then finish the inner diameter of the workpiece to complete the final finishing.

[0057] (4) Measure the wall thickness and compare it with the dimensions on the drawing to ensure the accuracy of the processing dimensions.

[0058] Finally, a laser tracker is used to measure on the machine tool to ensure that the workpiece ultimately meets the dimensional requirements of the drawings.

[0059] The surface of the ultra-large diameter Tederic ring forging, after performance heat treatment, is covered with oxide scale, which is completely removed by a finishing process. The final finishing stage and finished product of the ultra-large diameter Tederic ring forging prepared by this invention are as follows: Figure 1 As shown, the shaded area represents the final shape of the replacement ring, while the outer ring represents the theoretical current contour shape of the workpiece after performance heat treatment.

[0060] The inventors conducted relevant tests on the prepared product, and the specific results are as follows:

[0061] Table 1 Product Comparison

[0062]

[0063] The existing processing techniques in the table above all involve processing each part separately with allowance. Compared with the product of this invention, the workpiece is flipped twice more, which increases the working time and processing cost to a certain extent. The difference between this invention and the product of this invention is that the product of this invention only requires the workpiece to be flipped once, which greatly shortens the processing cycle by nearly 10-15 days and reduces the overall processing cost by about 200,000 yuan, resulting in significant overall benefits.

[0064] Furthermore, as those skilled in the art will know, improving the accuracy of dimensional tolerances and geometric tolerances is extremely difficult. Compared with the prior art, the present invention can achieve an improvement of about 1 mm in dimensional tolerances and about 0.7 mm in geometric tolerances, which is a very significant technological advancement.

[0065] Comparative Example 1

[0066] Compared with Example 1, the final finishing process parameters are different: the lathe speed is 2.2 rad / min, the feed rate is set to 0.55 mm / min, and the depth of cut is set to 0.4 mm; the remaining steps are the same as in Example 1.

[0067] Comparative Example 2

[0068] Compared with Example 1, the final finishing process parameters are different: the lathe speed is 3.3 rad / min, the feed rate is set to 0.5 mm / min, and the depth of cut is set to 0.5 mm; the remaining steps are the same as in Example 1.

[0069] Comparative Example 3

[0070] Compared with Example 1, the final finishing process parameters are different: the lathe speed is 3.2 rad / min, the feed rate is set to 0.5 mm / min, and the depth of cut is set to 0.3-0.5 mm; the remaining steps are the same as in Example 1.

[0071] Table 2. Effects of different process parameters on surface quality

[0072] project Surface roughness Example 1 Ra3.2 Comparative Example 1 Ra5.2 Comparative Example 2 Ra4.5 Comparative Example 3 Ra4.2

[0073] In the machining process of this invention, by continuously optimizing the machining process parameters and matching the lathe speed and feed rate, the depth of cut is reduced to achieve the level of this invention. In this invention, the lathe speed for final finishing is 2.4-3.2 rad / min, the feed rate is set to 0.5 mm / min, and the depth of cut is set to 0.3-0.5 mm. Under these conditions, the surface quality is better, achieving a workpiece surface roughness of Ra3.2, which is an improvement of Ra1-2 compared to the comparative example. Those skilled in the art will know that improving the surface quality during cold working, even to Ra1, is extremely difficult.

Claims

1. A method for processing an ultra-large diameter changing ring, characterized in that, Includes the following steps: (1) Align the workpiece; (2) Set the outer diameter baseline of the small end of the workpiece; set two workpiece height baselines as upper and lower baselines, and the vertical distance between the upper and lower baselines is 10mm; (3) Semi-finish the small end plane, outer diameter and R arc surface, observe the oxide scale after the performance heat treatment, press down the upper and lower reference lines until all the oxide scale is removed, and obtain the reference line of the final height. (4) Inner diameter of semi-finished workpiece; (5) Finish machining of the outer diameter of the large end; (6) Flip the workpiece over, and use the small end plane as a reference to finish machine the large end plane and the remaining outer diameter of the large end of the chuck; (7) Finish machining of the inner diameter; Furthermore, the specific method for aligning the workpiece in step (1) is as follows: Place the workpiece with the large end facing down and align it. Use a dial indicator to align the workpiece with the outer diameter of the large end and the outer diameter of the small end. Control the dial indicator head clearance error within the range of 0-5mm and calibrate the center of the workpiece. The specific method for step (2) is as follows: Set the small end outer diameter baseline of the workpiece, and machine a reference circle on the small end outer diameter of the workpiece as the baseline of the small end outer diameter; set two workpiece height baselines, and machine a 0.5mm deep groove on the small end outer diameter as the lower baseline position of the Z coordinate origin; 10mm above the lower baseline, machine a 0.5mm deep groove on the small end outer diameter as the upper baseline position of the Z coordinate origin. The specific method for step (3) is as follows: Set the reference line Z=0 on the Z-axis zero point. Move the X zero point 10mm inward from the outer diameter of the small end as the reference point. Program the CNC vertical lathe and semi-finish the small end plane, outer diameter and R-arc surface. Observe the oxide scale on the workpiece. After each pass, advance the X-axis by 4mm and continue to set the origin for machining. If oxide scale still exists during the process, continue to press down the upper and lower reference lines and the reference line of the outer diameter of the small end until all oxide scale is removed. The specific requirements for the inner diameter of the semi-finished workpiece in step (4) are: the inner diameter of the workpiece should be machined to leave a 5mm allowance on one side; In step (5) finishing the outer diameter of the large end, the outer diameter of the large end is the outer diameter of the part held by the large end jaws; The specific method for step (6) is as follows: Position the flipped workpiece with the small end plane as the reference. Use a dial indicator to align the workpiece with the outer diameter of the large end until the error is less than 1mm. Finish machine the large end plane and clamp the remaining outer diameter of the large end. If there is still oxide scale on the large end plane, continue to press down the reference line by 2mm until all the oxide scale is removed. The specific method for finishing the inner diameter of the workpiece in step (7) is as follows: Two workpiece height reference lines are set. The lower reference line is located at the point where a 0.5mm deep groove is machined on the outer diameter of the large end. The upper reference line is located 10mm above the lower reference line and a 0.5mm deep groove is machined on the outer diameter of the large end. The inner diameter of the workpiece is then finished to complete the final finishing. The lathe speed for the final finishing is 2.4-3.2 rad / min, the feed rate is set to 0.5mm / min, and the depth of cut is set to 0.3-0.5mm, which can achieve the quality requirement of Ra3.2 surface roughness of the workpiece.

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