Precision Machining and Forming Method for Special-shaped Ring with Aerospace Grooved Cross-section

Abstract

The present invention discloses a precision machining and forming method for an aviation special-shaped ring with a grooved cross-section, which includes the following steps. S1: Forging design: Design the rolling forging according to the deformation law of the metal during the near-net rolling forming process of the ring and the filling characteristics of the cross-sectional profile. The rolling forging design adopts the allowance placement design methods of equal allowance and non-equal allowance. S2: Near-net rolling forming: By adopting the forging method of near-net rolling forming, force the diameter of the rolling ring to increase, and the cross-sectional profile is gradually formed to obtain a rolling forging that meets the requirements of machining and forming. S3: Turning forming: Carry out the turning forming of the rolling ring according to the dimensional requirements of the target part to further improve the dimensional accuracy and surface quality of the ring. The present invention can accurately form the rolling forging, only perform a small amount of cutting on the forging, realize the high-efficiency, low-consumable and high-precision manufacturing of the ring, and can improve the comprehensive mechanical properties of the ring.

Description

Technical Field

[0001] The present invention belongs to the technical field of metal processing, and particularly relates to a precision machining and forming method for an aviation special-shaped ring with a grooved cross-section. Background Art

[0002] The special-shaped ring with a grooved cross-section is a typical component of an aeroengine and plays an important role in the aeroengine. The structure of such a ring is relatively complex and is usually composed of multiple stepped mutations. The inner surface of the ring is a smooth straight wall, and the outer surface is a symmetric grooved surface. The diameter is generally between 40 mm and 1000 mm (such as a bearing ring and an outer casing of an outer bypass duct), and there are extremely high requirements for the forming quality and performance of the ring.

[0003] Ring rolling forming is an advanced forging technology mainly used for producing high-performance seamless ring-shaped parts and is widely used in the aerospace field. Metal turning forming is a typical part processing technology, and a complex cross-sectional profile that meets the requirements can be obtained through turning processing. However, due to the characteristics of metal flow in rolling forming, it is difficult for traditional rolling forming to ensure that when the diameter of the ring reaches the design requirements, its cross-sectional profile can be filled completely.

[0004] Currently, the manufacturing of the special-shaped ring with a grooved cross-section mainly obtains a ring with a rectangular cross-section that meets the requirements through ring rolling, and then uses machining technology to process the ring, and gradually forms the grooved cross-sectional profile of the ring.

[0005] Obviously, directly machining the ring with a rectangular cross-section will result in a large area of cutting, leading to low material utilization rate, prolonged processing time of the ring, and reduced production efficiency of the ring.

[0006] In addition, a large amount of cutting will also cause the integrity of the metal streamline of the ring to be damaged, reducing the service life of the ring.

[0007] Therefore, it is urgent to develop a precision machining and forming method for an aviation special-shaped ring with a grooved cross-section to achieve high-performance, high-precision and low-consumable manufacturing of such rings. Summary of the Invention

[0008] The purpose of the present invention is to provide a precision machining and forming method for an aviation special-shaped ring with a grooved cross-section, to realize high-performance net near-rolling forming of the special-shaped ring with a grooved cross-section, effectively improve the filling accuracy of the rolling cross-sectional profile of the ring, so that only a small amount of cutting is required during the machining and forming process of the ring, greatly improving the material utilization rate of ring manufacturing, and the small amount of cutting basically retains the original mechanical properties of the ring, improving the comprehensive service performance of the ring and extending the service life of the ring.

[0009] The technical solution adopted by the present invention is as follows:

[0010] Precision machining and forming method for an aviation grooved cross-section special-shaped ring part, including,

[0011] Step 1, forging design. Place equal allowances on the inner and outer surfaces of the target part to obtain the initial rolling forging geometric dimensions of the rolling forging. Calculate the large-ring wall thickness value T of the initial rolling forging respectively, b and the maximum forming limit value T of the large-ring wall thickness of the corresponding formed forging, b-max where the target part refers to the final part dimensions after turning;

[0012] If T b-max ≥T b , execute Step 2. If T b-max <T b , then increase the allowance in the groove area of the ring part to obtain the updated final rolling forging geometric dimensions of the rolling forging. Then, calculate the large-ring wall thickness value T of the updated final rolling forging again, b and the maximum forming limit value T of the large-ring wall thickness of the corresponding formed forging, b-max , until T b-max ≥T b ;

[0013] Step 2, near-net rolling forming. Select a rolling ring blank as the blank, and adopt radial near-net rolling forming. The radial near-net rolling forming includes a driving roll and a core roll. The driving roll rotates actively and contacts the outer ring surface of the rolling ring blank; the core roll rotates driven and feeds radially, and contacts the inner ring surface of the rolling ring blank;

[0014] Step 3, turning forming. Perform turning machining on the near-net rolling formed forging obtained in Step 2 to remove the excess allowance.

[0015] As an option, in the said Step 1,

[0016] The large-ring wall thickness value T of the rolling forging b is calculated according to the following formula:

[0017]

[0018] where D b is the outer diameter of the large ring of the rolling forging, d is the inner diameter of the rolling forging, and the inner diameter of the large ring and the small ring of the rolling forging are the same, both being d;

[0019] The maximum forming limit value T of the large-ring wall thickness of the formed forging b-max is calculated according to the following formula:

[0020] T b-max =εT s +(1 - ε)T0;

[0021] Wherein, T0 is the wall thickness of the rolled ring blank, and T s is the wall thickness of the small ring of the rolled forging, ε is the rolling deformation coefficient of the cross-sectional profile of the grooved ring part, and T0, T s and ε are calculated according to the following formulas respectively:

[0022] T0 = T s - ΔH; wherein, ΔH is the rolling deformation amount;

[0023] wherein, D s is the outer diameter of the small ring of the rolled forging, and d is the inner diameter of the rolled forging;

[0024] wherein, B b is the height of the large ring of the rolled forging, B is the total height of the rolled forging, and T b is the wall thickness value of the large ring of the rolled forging.

[0025] As an option, in the step 2, the radial near-net rolling forming further includes conical rollers, and the roller surfaces of a pair of the conical rollers are respectively closely attached to the upper end face and the lower end face of the axial direction of the rolled ring blank.

[0026] As an option, the inner diameter d0 and the outer diameter D0 of the rolled ring blank are calculated according to the following formulas:

[0027] d0 = d c + 2Δs, where Δs is the gap between the inner hole of the rolled ring blank and the core roller;

[0028] wherein, B0 is the height of the rolled ring blank, and V is the volume of the rolled forging.

[0029] As an option, in the step 2, the feed speed v of the core roller is calculated according to the following formula:

[0030] v min ≤ v ≤ v max :

[0031] wherein, v min is the minimum rolling feed speed, v max is the maximum rolling feed speed, and v min and v max are determined by the following formulas respectively:

[0032]

[0033]

[0034] wherein, D d is the diameter of the driving roller, D cis the diameter of the core roll, D0 is the outer diameter of the rolled ring blank, d0 is the inner diameter of the rolled ring blank, n1 is the rotational speed of the driving roll, and β is the contact friction angle.

[0035] As an option, in step 2, the feeding speed v of the core roll includes the feeding speed v1 in the biting stage, the feeding speed v2 in the hole expanding stage, and the feeding speed v3 in the full-round stage, and v3 < v1 < v2.

[0036] As an option, in step 3, the removal of the surplus is carried out in two steps:

[0037] In the first step, the surplus in the groove area of the ring part is turned to obtain the geometric dimensions of the initial rolled forging.

[0038] In the second step, the surplus on the outer surface, inner surface, and two end faces of the ring part is turned to obtain the geometric dimensions of the target part.

[0039] As an option, in step 3, the cutting speed v c is calculated according to the following formula:

[0040]

[0041] where D s is the outer diameter of the processed ring part, and n c is the rotational speed of the spindle of the turning equipment.

[0042] Compared with the prior art, the features of the present invention are shown in:

[0043] (1) A design method for the near-net-shape rolled forging of the ring part is given according to the characteristics of the near-net-shape rolling forming process of the ring part.

[0044] (2) By adopting the design method of placing the surplus with equal surplus (obtaining the initial rolled forging) and non-equal surplus (adding surplus only at the groove on the basis of the initial rolled forging, and continuously iterating and judging T b-max ≥T b to obtain the final rolled forging), a rolled forging that can be precisely near-net-shape rolled is designed, ensuring that the ring part can be precisely formed during the near-net-shape rolling forming process, improving the quality, precision, and mechanical properties of the near-net-shape rolling forming of the ring part. (3) The geometric dimensions of the target part are machined by turning forming, and compared with the traditional turning process, this turning forming only requires a small amount of cutting, ensuring the integrity of the metal streamline during the rolling process of the ring part, improving the mechanical properties and service life of the turned ring part. At the same time, the small amount of cutting also improves the processing efficiency during the processing of the ring part.

[0045] The present invention can design a precisely near-net-shape rolled forging, greatly reducing the turning surplus of the ring part, shortening the turning processing cycle, and overall improving the production efficiency and performance of the ring part. Brief Description of the Drawings

[0046] Figure 1 is a schematic diagram of the special-shaped ring part with a grooved cross-section for aviation related to the present invention;

[0047] Figure 2 is a schematic diagram of the initial rolling forging of the special-shaped ring with a grooved cross-section for aviation related to the present invention;

[0048] Figure 3 is a schematic diagram of the final rolling forging of the special-shaped ring with a grooved cross-section for aviation related to the present invention;

[0049] Figure 4 is a design flow chart of the rolling forging of the special-shaped ring with a grooved cross-section for aviation related to the present invention;

[0050] Figure 5 is a schematic diagram of the rolled ring blank of the special-shaped ring with a grooved cross-section for aviation related to the present invention;

[0051] Figure 6 is a schematic diagram of the initial rolling moment of the special-shaped ring with a grooved cross-section for aviation related to the present invention;

[0052] Figure 7 is a schematic diagram of the final rolling moment of the special-shaped ring with a grooved cross-section for aviation related to the present invention;

[0053] Figure 8 is a schematic diagram of the feed speed during the rolling process of the special-shaped ring with a grooved cross-section for aviation related to the present invention;

[0054] Figure 9 is a schematic diagram of the cutting of the grooved area of the initial forging of the special-shaped ring with a grooved cross-section for aviation related to the present invention;

[0055] Figure 10 is a schematic diagram of the cutting of the final forging of the special-shaped ring with a grooved cross-section for aviation related to the present invention;

[0056] Figure 11 is a schematic diagram of the speed during the turning forming process of the special-shaped ring with a grooved cross-section for aviation related to the present invention;

[0057] In the figure, 1 - driving roller, 2 - ring blank, 3 - core roller, 4 - tapered roller, 5 - rolling forging. Detailed Embodiments

[0058] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. However, it should not be understood that the scope of the subject matter of the present invention is limited to the following embodiments. Without departing from the above technical idea of the present invention, all modifications, substitutions, and changes made according to ordinary technical knowledge and customary means in the art are included in the scope of the present invention.

[0059] Take Figure 1Taking the shown aviation grooved cross-section special-shaped ring as the object, the steps of its forming process method include:

[0060] Step 1, forging design:

[0061] For the design of the rolled forging 5, first, equal allowances are placed on the inner and outer surfaces of the part to obtain the rolled forging 5, as Figure 2 shown; then, by comparing the wall thickness values of the rolled forging 5 and its formed forging large ring. If the maximum forming limit value of the wall thickness of the formed forging large ring is greater than or equal to the wall thickness value of the large ring of the rolled forging 5, the rolled forging 5 that meets the near-net rolling forming requirements can be obtained; if the judgment is not established, it is necessary to increase the allowance in the groove area of the ring to obtain the new size of the rolled forging 5, as Figure 3 shown.

[0062] Secondly, for the rolled forging 5 after increasing the allowance, judge again whether the maximum forming limit value of its formed forging large ring is greater than or equal to the wall thickness value of the large ring of the rolled forging 5. And so on, continuously iterating and calculating until after increasing the allowance, the maximum forming limit value of the formed forging large ring is greater than or equal to the wall thickness value of the large ring of the rolled forging 5, then the rolled forging that meets the processing requirements can be obtained; the flow chart of the forging design process is as Figure 4 shown.

[0063] It should be noted that the rolled forging 5 refers to the forging obtained after placing equal and unequal allowances on the part surface, mainly referring to the theoretical calculated size of the forging. Among them, the rolled forging 5 can be divided into the initial rolled forging and the final rolled forging. The initial rolled forging refers to the forging after placing equal machining allowances on the part; the final rolled forging is obtained by continuously superimposing and optimizing the initial rolled forging. When the judgment formula T b-max ≥T b does not meet the requirements, the initial rolled forging needs to be optimized. At this time, the machining allowance is continuously increased in the groove area of the initial rolled forging, and then the forging size that meets the forming requirements is obtained. At this time, the theoretical size of this forging is the size of the final rolled forging.

[0064] The formed forging refers to the forging obtained after the rolled forging 5 undergoes the rolling forming process, mainly referring to the size after the ring is actually processed and formed. It should be noted that within a certain error range, when the judgment formula T b-max ≥T b meets the requirements, the size of the final rolled forging should be consistent with the size of the formed forging.

[0065] Therefore, the rolled forging refers to the ring with the theoretical design size, and the formed forging refers to the ring after the theoretically designed rolled forging is processed by the actual rolling process

[0066] In the above scheme, according to the geometric dimensions of the rolled forging 5, the wall thickness T of its large ringb and the wall thickness T of the small ring s are calculated respectively according to the following formulas:

[0067]

[0068] wherein, D b is the outer diameter of the large ring of the rolled forging 5, d is the inner diameter of the rolled forging 5, and D s is the outer diameter of the small ring of the rolled forging 5.

[0069] In the above solution, since the rolled ring blank 2 is always in contact with the rolling mill rolls during the rolling process, therefore, the wall thickness T0 of the rolled ring blank 2 can be determined by the following formula:

[0070] T0 = T s - ΔH;

[0071] wherein, ΔH is the rolling deformation amount.

[0072] In the above solution, the maximum forming limit value of the wall thickness of the large ring of the formed forging is calculated according to the following formula:

[0073] T b-max = εT s + (1 - ε)T0;

[0074] wherein, T0 is the wall thickness of the rolled ring blank 2, T s is the wall thickness of the small ring of the rolled forging 5, T b-max is the maximum forming limit value of the wall thickness of the large ring of the formed forging, ε is the rolling deformation coefficient of the cross-sectional profile of the grooved ring part, and here B b is the height of the large ring of the rolled forging 5, B is the total height of the rolled forging 5, and T b is the wall thickness value of the large ring of the rolled forging 5.

[0075] In the above solution, the judgment condition for the maximum forming limit value of the wall thickness of the large ring of the formed forging and the wall thickness value of the large ring of its rolled forging 5 is as follows:

[0076]

[0077] When the forming limit of the wall thickness of the large ring of the formed forging is greater than or equal to the wall thickness value of the corresponding large ring of its rolled forging 5, the cross-sectional profile of the grooved cross-section special-shaped ring part can be formed; at this time, the designed geometric dimensions of the rolled forging 5 meet the requirements of the near-net rolling forming process. On the contrary, the cross-sectional profile of the grooved cross-section special-shaped ring part cannot be near-net rolled and formed.

[0078] Step 2, near-net rolling forming:

[0079] For the rolled forging 5 designed in Step 1, carry out the near-net rolling forming process on it, such as Figure 6As shown. The rolling process adopts the radial near-net rolling forming process. The driving roll 1 rotates actively, and the core roll 3 rotates driven and feeds radially. Under the action of the driving roll 1 and the core roll 3, the rolled ring blank 2 gradually undergoes continuous cumulative plastic deformation, forcing the cross-sectional profile of the ring to be gradually filled and the diameter to gradually expand, and then forming the designed rolled forging 5, as Figure 7 shown. When the rolled forging 5 is formed, the core roll 3 is withdrawn and the rolled forging 5 is taken out.

[0080] In the above solution, in order to ensure that the core roll 3 can smoothly pass through the inner hole of the rolled ring blank 2, the inner diameter of the rolled ring blank 2 can be calculated by the following formula:

[0081] d0 = d c + 2Δs;

[0082] where, d0 is the inner diameter of the rolled ring blank 2, d c is the diameter of the core roll 3, and Δs is the gap between the inner hole of the rolled ring blank 2 and the core roll 3.

[0083] In the above solution, due to the adoption of the radial rolling process, during the entire rolling process, the height of the ring remains basically unchanged; therefore, the height B0 of the rolled ring blank 2 always remains the same as the height B of the rolled forging 5. According to the principle of constant volume in plastic forming, the outer diameter of the rolled ring blank 2 can be calculated by the following formula:

[0084]

[0085] where, D0 is the outer diameter of the rolled ring blank 2, B0 is the height of the rolled ring blank 2, V is the volume of the rolled forging 5, and

[0086] In the above solution, the feed v of the core roll 3 is calculated by the following formula, and the feed speed planning during the rolling process is as Figure 8 shown:

[0087] v min ≤ v ≤ v max :

[0088] where, v min is the minimum rolling feed speed, v max is the maximum rolling feed speed; and v min and v max can be determined by the following formulas respectively:

[0089]

[0090]

[0091] where, D d is the diameter of the driving roll, D cis the core roll diameter, D0 is the outer diameter of the rolled ring blank 2, d0 is the inner diameter of the rolled ring blank 2, n1 is the driving roll speed, and β is the contact friction angle.

[0092] Step 3, turning forming:

[0093] The near-net rolled and formed forging is machined by turning to remove the excess allowance. The turning process is carried out on a horizontal machine tool; the fixture drives the rolled forging 5 to rotate under the action of the machine tool spindle, and the excess allowance is gradually cut off by the tool. The turning process is divided into two steps. First, the excess allowance in the groove area of the ring part is turned to obtain the geometric dimensions of the initial rolled forging, as Figure 9 shown; second, the allowances on the outer surface, inner surface, and two end faces of the ring part are turned to obtain the geometric dimensions of the target part, as Figure 10 shown.

[0094] In the above solution, the cutting speed v c can be calculated according to the following formula, and the speed planning of the turning process is as Figure 11 shown:

[0095]

[0096] where D s is the outer diameter of the machined ring part (referring to the outer diameter of the ring part clamped on the lathe, as Figure 9 shown, at this time D s refers to the outer diameter D b ) of the large ring of the grooved cross-section special-shaped ring part, and n c is the spindle speed of the turning equipment.

[0097] Embodiment

[0098] Next, taking the Figure 1 aerospace grooved cross-section special-shaped ring part as an example, the forming process method of the aerospace grooved cross-section special-shaped ring part of the present invention will be further described.

[0099] For the convenience of understanding, the meanings of each letter symbol in Figure 1 , 2 , 3, 4, 7 are listed as follows:

[0100] Figure 1 In: D bf - The outer diameter of the large ring of the target part, D sf - The outer diameter of the small ring of the target part, d f - The inner diameter of the target part, B bf - The height of the large ring of the target part, B sf - The height of the small ring of the target part, B f - The total height of the target part, Figure 1 The definitions of the large ring and the small ring are also marked in;

[0101] Figure 2 Among them: D b - Outer diameter of the large ring of the initial rolling forging, D s - Outer diameter of the small ring of the initial rolling forging, d - Inner diameter of the initial rolling forging, B b - Height of the large ring of the initial rolling forging, B s - Height of the small ring of the initial rolling forging, B - Total height of the initial rolling forging;

[0102] Figure 3 Among them is the final rolling forging, which is obtained by adding extra machining allowance to the initial rolling forging in its groove area. Therefore, only the outer diameter of the small ring, the height of the large ring, and the height of the small ring have changed, and other values remain unchanged, remaining consistent with the initial rolling forging: D b - Outer diameter of the large ring of the final rolling forging, D s1 - Outer diameter of the small ring of the final rolling forging, d - Inner diameter of the final rolling forging (equal to the inner diameter d of the initial rolling forging), B b1 - Height of the large ring of the final rolling forging, B s1 - Height of the small ring of the final rolling forging, B - Total height of the final rolling forging;

[0103] Figure 4 Among them: T0 - Wall thickness of the rolled ring blank, T s - Wall thickness of the small ring of the rolling forging, T b - Wall thickness of the large ring of the rolling forging,

[0104] T b-max - Ultimate wall thickness of the large ring of the rolling forging after rolling forming (maximum ultimate wall thickness of the large ring of the formed ring part), ε - Section profile deformation coefficient of the grooved ring part;

[0105] Figure 7 Is the formed part of the final rolling forging, and its forming value and theoretical value satisfy the judgment formula T b-max ≥T b . Therefore, Figure 7 Among them, the dimensional values of the grooved ring part after rolling forming are consistent with those of the final rolling forging( Figure 3 ), and their letter meanings are also the same.

[0106] The dimensions of the target part of the grooved cross-section special-shaped ring part are: d f = 798mm, D sf = 820mm, D bf = 850mm, B f = 48mm, B bf = 5mm, B sf = 38mm. The specific steps of the forming method of the grooved cross-section special-shaped ring part are as follows:

[0107] (1) Forging design:

[0108] For the design of the rolled forging 5, first, equal machining allowances are placed on the inner and outer surfaces of the part to obtain the rolled forging 5. As Figure 2 shown, the dimensions of the rolled forging 5 are: d = 792 mm, D s = 826 mm, D b = 856 mm, B = 54 mm, B b = 11 mm, B s = 32 mm. According to the rolling deformation, the wall thickness T0 of the rolled ring blank 2 is calculated to be 49 mm. According to the dimensions of the rolled forging 5 and the calculation formula for the maximum forming limit value of the wall thickness of the large ring of the formed forging, the wall thickness values of the large rings of the formed forging and the rolled forging 5 are calculated to be: T b = 32 mm and T b-max = 30.12 mm respectively; then, by comparing the wall thickness values of the large rings of the formed forging and the rolled forging 5. Obviously, the maximum forming limit value of the wall thickness of the large ring of the formed forging is less than the wall thickness value of the large ring of the rolled forging 5. Therefore, machining allowances need to be added in the groove area of the ring to obtain the new dimensions of the rolled forging 5. As Figure 3 shown, the dimensions of the new rolled forging 5 are: d = 792 mm, D s1 = 834 mm, D b = 856 mm, B = 54 mm, B b1 = 12 mm, B s1 = 30 mm. For the rolled forging 5 with added machining allowances, the calculated wall thickness value of the large ring of its formed forging is T b-max = 33.32 mm. Once again, it is judged whether the maximum forming limit value of the wall thickness of the large ring of its formed forging is greater than or equal to the wall thickness value of the large ring of the rolled forging 5. Obviously, the maximum forming limit value of the wall thickness of the large ring of the formed forging is greater than the wall thickness value of the large ring of the rolled forging 5. Therefore, the rolled forging 5 that meets the processing requirements can be obtained; the process flow chart of the forging design is as Figure 4 shown.

[0109] (2) Near-net shape rolling forming:

[0110] For the rolled forging 5 designed in step (1), the near-net shape rolling forming process is carried out on it. As Figure 6 shown, the dimensions of its rolled ring blank 2 are: d0 = 381 mm, B0 = 54 mm, D0 = 479 mm. The radial near-net shape rolling forming process is adopted during the rolling process. The driving roll 1 rotates actively, and the core roll 3 rotates driven and feeds radially; under the action of the driving roll 1 and the core roll 3, the ring blank 2 gradually undergoes continuous cumulative plastic deformation, forcing the cross-sectional profile of the ring to be gradually filled and the diameter to gradually expand, and then the designed rolled forging 5 is formed. As Figure 7 shown. When the rolled forging 5 is formed, the core roll 3 is withdrawn and the forging is taken out.

[0111] During the rolling process, it is planned in three stages, namely the rolling bite stage, the hole expansion stage and the full-circle stage. The feed rate v1 in the rolling bite stage is 1 mm / s, the feed rate v2 in the rolling hole expansion stage is 2.5 mm / s, and the feed rate v3 in the full-circle stage is 0.8 mm / s.

[0112] (3) Turning forming:

[0113] The near-net rolled and formed forging is machined by turning to remove the excess allowance. The turning process is carried out on a horizontal machine tool; the fixture drives the rolled forging 5 to rotate under the action of the machine tool spindle, and the excess allowance is gradually cut off by the tool. The turning process is divided into two steps. In the first step, the excess allowance in the groove area of the ring part is turned to obtain the geometric dimensions of the initial forging as follows: d = 792 mm, D s1 = 834 mm, D b = 856 mm, B = 54 mm, B b1 = 30 mm, B s1 = 12 mm, as Figure 9 shown; in the second step, the allowances on the outer surface, inner surface and two end faces of the ring part are turned to obtain the geometric dimensions of the target part as follows: d f = 798 mm, D sf = 820 mm, D bf = 850 mm, B f = 48 mm, B bf = 5 mm, B sf = 38 mm, as Figure 10 shown.

[0114] During the turning forming process, the entire cutting forming is carried out in two steps. When turning the excess allowance in the groove area of the ring part in the first step, the turning feed rate is 0.6 mm / s; when turning the allowances on the outer surface, inner surface and two end faces of the ring part in the second step, the turning feed rate is 0.25 mm / s. The planning of the turning feed rate in the entire turning process is as Figure 11 shown.

[0115] The content not described in detail in the specification of the present invention belongs to the prior art well-known to those skilled in the art. Although the illustrative specific embodiments of the present invention are described above for the convenience of those skilled in the art to understand the present invention, it should be clear that the present invention is not limited to the scope of the specific embodiments. For those of ordinary skill in the art in this technical field, as long as various changes are within the spirit and scope of the present invention defined and determined by the appended claims, these changes are obvious, and all inventions and creations using the concept of the present invention are within the scope of protection.

Claims

1. A precision machining and forming method for a special-shaped ring with an aviation trough-shaped cross-section, characterized in that: including Step 1, forging design, equal machining allowances are placed on the inner and outer surfaces of the target part to obtain the initial rolling forging geometry of the rolled forging (5), and the large-ring wall thickness value T of the initial rolling forging is calculated respectively b and the maximum forming limit value T of the large-ring wall thickness of the corresponding formed forging b-max ; The large-ring wall thickness value T of the rolled forging (5) b is calculated according to the following formula: ; wherein, D b is the outer diameter of the large ring of the rolled forging (5), and d is the inner diameter of the rolled forging (5); The maximum forming limit value T of the large ring wall thickness of the formed forging b-max It is calculated according to the following formula: ； Wherein, T0 is the wall thickness of the rolled ring blank (2), and T s is the wall thickness of the small ring of the rolled forging (5), ε is the rolling deformation coefficient of the cross-sectional profile of the grooved ring part, and T0, T s and ε are calculated according to the following formulas respectively: ; wherein, ΔH is the rolling deformation amount; ; wherein, D s is the outer diameter of the small ring of the rolled forging (5), and d is the inner diameter of the rolled forging (5); - ; wherein, B b is the height of the large ring of the rolled forging (5), B is the total height of the rolled forging (5), and T b is the wall thickness value of the large ring of the rolled forging (5); If T b-max ≥T b , perform step 2. If T b-max <T b , then add a margin to the groove area of the ring part to obtain the updated final rolling forging geometry of the rolling forging (5), and then recalculate the large ring wall thickness value T b of the updated final rolling forging and the maximum forming limit value T b-max of the large ring wall thickness of its corresponding forming forging until T b-max ≥T b is satisfied; Step 2, near-net rolling forming. Select the rolled ring blank (2) as the blank, and adopt radial near-net rolling forming. The radial near-net rolling forming includes a driving roll (1) and a core roll (3). The driving roll (1) rotates actively and contacts the outer ring surface of the rolled ring blank (2). The core roll (3) rotates passively and feeds radially, and contacts the inner ring surface of the rolled ring blank (2). The feeding speed of the core roll (3) v includes the feeding speed in the biting stage v 1 、 the feeding speed in the hole expanding stage v 2 and the feeding speed in the full-round stage v 3 , and v 3 ＜v 1 ＜v 2 ; Step 3: turning and forming, performing turning on the near-net rolled and formed forging obtained in Step 2 to remove the excess allowance.

2. The precision machining and forming method of the special-shaped ring with an aviation trough-shaped cross-section according to claim 1, characterized in that: In the said Step 2, the radial near-net rolling forming further includes tapered rollers (4), and the roller surfaces of a pair of said tapered rollers (4) are respectively in close contact with the upper axial end face and the lower axial end face of the rolled ring blank (2).

3. The precision machining and forming method of the special-shaped ring with an aviation trough-shaped cross-section according to claim 1, characterized in that: The inner diameter d0 and the outer diameter D0 of the said rolled ring blank (2) are calculated according to the following formula: , where Δs is the gap between the inner hole of the rolled ring blank (2) and the core roll (3); , where B0 is the height of the rolled ring blank (2), and V is the volume of the rolled forging (5).

4. The precision machining and forming method of the special-shaped ring with an aviation trough-shaped cross-section according to claim 1, characterized in that: In the said step 2, the feeding speed of the core roll (3) v is calculated according to the following formula: ； Among them, v min is the minimum rolling feed rate, v max is the maximum rolling feed rate, and v min and v max are respectively determined by the following formulas: ； ； where D d is the diameter of the driving roll (1), D c is the diameter of the core roll (3), D0 is the outer diameter of the rolled ring blank (2), d0 is the inner diameter of the rolled ring blank (2), n1 is the rotational speed of the driving roll (1), and β is the contact friction angle.

5. The precision machining and forming method of the special-shaped ring part with an aviation trough-shaped cross-section according to claim 1, characterized in that: In the said Step 3, removing the allowance by turning is carried out in two steps: The first step: turning the excess allowance in the groove area of the ring part to obtain the geometric dimensions of the initial rolled forging; The second step: turning the allowances on the outer surface, the inner surface and the two end faces of the ring part to obtain the geometric dimensions of the target part.

6. The precision machining and forming method of the special-shaped ring with an aviation trough-shaped cross-section according to claim 1, characterized in that: In step 3, the cutting speed v c is calculated according to the following formula: ； Among them, D s is the outer diameter of the machined ring part, and n c is the spindle speed of the turning equipment.

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