A method and device for cold-expansion of a ring-shaped forging

Abstract

The present application relates to the field of forging forming technology, in particular to a kind of annular forging cold expansion shape correcting method and shape correcting device, wherein method includes the following steps: S1, find out the minimum diameter of deformed annular forging by measurement;S2, deformed annular forging is placed on general expansion tooling, and spacer is arranged between annular forging and expansion tooling, the spacer is arranged at the both ends of the minimum diameter of the annular forging;S3, slowly run equipment, make expansion tooling push deformed annular segment piece inner wall along radial direction;S4, observe the clearance between deformed annular forging and expansion tooling, when the clearance is uniform, stop running equipment;S5, after removing spacer, run equipment again, make annular forging whole deformation, expansion tooling reaches preset stroke;S6, measure annular forging size, if size is qualified, then complete shape correcting;If size is still unqualified, then according to the steps S1-S5, shape correcting is carried out again.The present application can save annular piece oval and distortion caused by deformation out-of-tolerance.

Description

Technical Field

[0001] This invention relates to the field of forging technology, and in particular to a method and apparatus for cold expansion correction of annular forgings. Background Technology

[0002] During the processing of ring forgings, deformation of varying degrees often occurs during heat treatment and cold working processes. This is especially true when processing thin-walled parts. If the forging is deformed (including elliptical or torsional deformation) after roughing or semi-finishing, the machining allowance of the part is often only 1 to 2 mm. If the part cannot be corrected within the small deformation range, it will directly lead to the scrapping of the part and cause huge losses.

[0003] Therefore, a technical solution is needed to address the problem that ring forgings deform after roughing and semi-finishing, have limited allowance, and that directly using bulging tooling for expansion and straightening can easily lead to parts being scrapped due to exceeding tolerances. Summary of the Invention

[0004] The purpose of this invention is to address the technical problem that ring forgings deform after roughing and semi-finishing, have limited allowance, and are easily scrapped due to excessive tolerances when directly using expansion tooling for expansion and straightening. This invention provides a method and apparatus for cold expansion and straightening of ring forgings.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] A method for cold expansion correction of annular forgings includes the following steps:

[0007] S1. Determine the minimum diameter of the deformed ring forging by measurement;

[0008] S2. Place the deformed ring forging on a general expansion fixture, and place a spacer between the ring forging and the expansion fixture. The spacer is placed at both ends of the minimum diameter of the ring forging.

[0009] S3. Slowly operate the equipment so that the expansion fixture pushes against the inner wall of the deformed annular forging in the radial direction;

[0010] S4. Observe the gap between the deformed ring forging and the expansion tooling. When the gap is uniform in all places, stop running the equipment.

[0011] S5. After removing the pad, run the equipment again to deform the ring forging as a whole and expand the tooling to reach the preset stroke.

[0012] S6. Measure the dimensions of the ring forging. If the dimensions are within acceptable limits, the forming process is complete. If the dimensions are still not within acceptable limits, repeat the forming process according to steps S1-S5.

[0013] This invention discloses a cold expansion and shaping method for annular forgings. First, the diameter of the deformed annular forging is measured using calipers to find and mark its minimum diameter. Then, the annular forging is placed on an expansion fixture, with pads placed at both ends of the minimum diameter. The expansion fixture is then activated to push against the inner wall of the annular forging. Due to the pads at the minimum diameter, the ends of the minimum diameter are pushed outwards by the expansion fixture, while the ends of the maximum diameter undergo inward contraction. Once the gaps between the annular forging and the expansion fixture are uniform (i.e., the elliptical annular forging becomes circular), the expansion fixture is stopped. Finally, the pads are removed, and the annular forging is expanded as a whole using the expansion fixture to reach the required dimensions, thus achieving the shaping of the annular forging.

[0014] As a preferred embodiment of the present invention, the qualified diameter of the annular forging is D, the minimum diameter of the deformed annular forging is d, and in step S4, the stroke of the expansion fixture after contacting the pad is s, where D - (d + 2s) ≥ 0.5 mm. During the first run of the expansion fixture, by controlling the stroke of the expansion fixture, a margin of at least 0.5 mm is left between the annular forging after the first expansion and the qualified size, thus ensuring a good corrective effect on the annular forging during the next overall expansion.

[0015] In a preferred embodiment of the present invention, in step S5, after the expansion fixture reaches the preset stroke, it remains stationary for a duration of t, where 3 ≤ t ≤ 5 min. After the annular forging reaches the qualified size through expansion by the expansion fixture, the pushing action of the expansion fixture on the annular forging is maintained for at least 3 minutes to reduce the subsequent deformation and shrinkage of the annular forging. At the same time, the duration of the pushing action does not exceed 5 minutes, shortening the forming cycle and improving production efficiency.

[0016] As a preferred embodiment of the present invention, the pad is made of a flexible material. When the expansion tool pushes against the inner wall of the annular forging, since the inner wall of the annular forging is a variable arc surface, if the pad is made of a rigid component with high strength, it may cause damage to the inner wall of the annular forging. By making the pad with a flexible material, the pad can adapt to the deformation of the arc surface inner wall of the annular forging, which on the one hand makes the pad fit more tightly with the annular forging and is not easy to slip off, and on the other hand avoids damage to the inner wall of the annular forging.

[0017] As a preferred embodiment of the present invention, the pad is made of wood. The wooden pad is softer than the annular forging, allowing it to deform adaptively with the annular forging without damaging the inner wall of the forging. Furthermore, the wooden pad has advantages such as low cost, readily available materials, and ease of processing.

[0018] As a preferred embodiment of the present invention, the pad is made of rubber. Rubber is relatively soft, like wood, and it also has the advantages of simple processing and ease of mass production.

[0019] In a preferred embodiment of the present invention, the pad block includes a plurality of pads, which are stacked in layers. When the size of the annular forging changes, or when the out-of-tolerance size of the annular forging changes, the pushing distance of the expansion fixture on the annular forging can be adjusted by increasing or decreasing the number of pads, thereby enabling the method to adapt to the shaping of more annular forgings.

[0020] In a preferred embodiment of the present invention, the thickness of the gasket is c, where c = 10 mm ± 2 mm. A thickness variation of 10 mm can accommodate the shaping and machining of most aerospace ring forgings.

[0021] A ring forging straightening device includes an expansion fixture and two pads. The expansion fixture is used to push against the inner wall of the ring forging, and the two pads are disposed between the expansion fixture and the ring forging, respectively located at both ends of the minimum diameter of the ring forging.

[0022] This invention discloses a ring forging straightening device. In use, the out-of-tolerance ring forging is placed on an expansion fixture. Two pads are placed between the expansion fixture and the ring forging, with the two pads located at the two ends of the minimum diameter of the ring forging. The two ends of the minimum diameter of the ring forging are pushed by the expansion fixture, resulting in outward expansion deformation, while the two ends of the maximum diameter of the ring forging will undergo a certain inward contraction deformation, thereby realizing the straightening operation of the elliptical or twisted ring forging.

[0023] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0024] The process designed in this invention has simple steps, requires no additional tooling, and requires no heating. This method can effectively eliminate deformations such as ellipticity and torsion in forgings, thus saving economic and time losses caused by excessive deformation of forgings. Attached Figure Description

[0025] Figure 1 This is a schematic diagram illustrating the operation of a cold expansion correction method for annular forgings according to the present invention.

[0026] The markings in the figure are: 1-ring forging, 2-expansion tooling, 3-spacer block, 31-spacer plate. Detailed Implementation

[0027] The present invention will now be described in detail with reference to the accompanying drawings.

[0028] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0029] Example 1

[0030] like Figure 1 As shown in the embodiment, a method for cold expansion correction of annular forgings is provided. This method can achieve small deformations within 1%, and the ellipticity of the annular forging 1 can be reduced from >20mm to within 3mm. The specific implementation process is as follows:

[0031] 1) Find the point with the smallest diameter of the deformed ring forging 1, i.e., the minimum diameter Φ, by measurement;

[0032] 2) Select a suitable general expansion tool 2 and place the ring forging 1. At the same time, add two symmetrical pads 3 at the minimum diameter. The pads 3 should be made of a soft material to prevent damage to the ring forging 1. The pads 3 consist of several shims 31. The thickness of each shim 31 is set to 10mm. The material of the shims 31 can be wood or rubber, etc.

[0033] 3) Slowly run the equipment to deform the ring forging 1. The part with the pad 3 is deformed first. During the deformation process, observe the gap between the rest of the ring forging 1 and the general expansion tool 2. Stop the deformation when the gaps are uniform. By selecting an appropriate number of pads 31, the elliptical ring forging 1 is transformed into a circle, and there is still a margin of at least 0.5mm. This facilitates the overall expansion of the ring forging 1 in subsequent processing. It is calculated that for every 1mm increase in the shortest diameter of the ring forging 1, the longest diameter is shortened by 0.57mm.

[0034] 4) After removing the pad block 3, run the equipment again to deform the ring forging 1 as a whole. After reaching the set size, hold the pressure for 3 to 5 minutes.

[0035] 5) Measure the dimensions of the ring forging 1. If the dimensions are acceptable, the rework is completed. If the dimensions are still unacceptable, find the smallest diameter and repeat the above steps until the dimensions are acceptable.

[0036] Example 2

[0037] like Figure 1 As shown, this embodiment provides a ring forging straightening device, including an expansion tool 2 and two pads 3. The expansion tool 2 is used to push against the inner wall of the ring forging 1, and the two pads 3 are disposed between the expansion tool 2 and the ring forging 1, and are respectively located at both ends of the minimum diameter of the ring forging 1.

[0038] In use, the out-of-tolerance annular forging 1 is placed on the expansion fixture 2. Two pads 3 are placed between the expansion fixture 2 and the annular forging 1, and the two pads 3 are respectively located at both ends of the minimum diameter of the annular forging 1. The ends of the minimum diameter of the annular forging 1 are pushed by the expansion fixture 2, resulting in outward expansion deformation, while the ends of the maximum diameter of the annular forging 1 will produce a certain inward contraction deformation, thereby realizing the correction operation of the elliptical or twisted annular forging 1.

[0039] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for cold expansion correction of annular forgings, characterized in that, Includes the following steps: S1. Find the minimum diameter of the deformed ring forging (1) by measurement; S2. Place the deformed ring forging (1) on the general expansion fixture (2) and set a pad (3) between the ring forging (1) and the expansion fixture (2). The pad (3) is set at both ends of the minimum diameter of the ring forging (1). The pad (3) includes a number of pads (31). The number of pads (31) are stacked. The thickness of the pad (31) is c, c=10mm±2mm. S3. Slowly run the equipment so that the expansion fixture (2) pushes against the inner wall of the deformed annular forging (1) in the radial direction; S4. Observe the gap between the deformed ring forging (1) and the expansion tool (2). When the gap is uniform, stop running the equipment. The qualified diameter of the ring forging (1) is D, and the minimum diameter of the deformed ring forging (1) is d. In step S4, the stroke of the expansion tool (2) after it abuts the pad (3) is s. D-(d+2s)≥0.5mm. For every 1mm increase in the shortest diameter of the ring forging (1), the longest diameter is shortened by 0.57mm. S5. After removing the pad block (3), run the equipment again to deform the ring forging (1) as a whole and make the expansion tool (2) reach the preset stroke. In step S5, after the expansion tool (2) reaches the preset stroke, it remains in the same position for a time of t, 3≤t≤5min. S6. Measure the dimensions of the ring forging (1). If the dimensions are qualified, the calibration is completed. If the dimensions are still not qualified, the calibration is performed again according to the steps S1-S5.

2. The method for cold expansion correction of annular forgings according to claim 1, characterized in that, The pad (3) is made of a flexible material.

3. The method for cold expansion correction of annular forgings according to claim 2, characterized in that, The pad (3) is made of wood.

4. The method for cold expansion correction of annular forgings according to claim 2, characterized in that, The pad (3) is made of rubber.

5. A device for straightening annular forgings, characterized in that, The method for cold expansion and straightening of an annular forging as described in any one of claims 1-4 includes an expansion fixture (2) and two pads (3). The expansion fixture (2) is used to push against the inner wall of the annular forging (1). The two pads (3) are disposed between the expansion fixture (2) and the annular forging (1) and are respectively located at both ends of the minimum diameter of the annular forging (1).

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