Method for manufacturing large-size thick-section fan disc forgings

Abstract

The application discloses a large-size thick-section fan disc forging manufacturing method, belongs to the field of forging, and aims to reduce the maximum section thickness of the fan disc forging and improve the performance of the forging. β (T β -50) ℃, is moved to a mold for pressing to form a rough blank, the rough blank is heated to (T β (T β -50) ℃, is transferred to a final forging die, is pressed into a forging by one fire, and the forging is air-cooled; the final forging die comprises an upper die and a lower die, a lower die boss is arranged at the center of a lower die cavity of the lower die, the lower die boss comprises a top section and a bottom section in the vertical direction, and the inclination angle of the bottom section is smaller than that of the top section. The forging fire times are not increased, the section change degree of the forging is greatly slowed down in the process from the pre-forging blank to the forging, the deformation amount is increased, the deformation distribution is more uniform, the effective deformation range is expanded, and the use requirements of the integral blade disc forging on the structure and performance are more easily met.

Description

Technical Field

[0001] This invention belongs to the field of forging, specifically a method for manufacturing large-size, thick-section fan disc forgings. Background Technology

[0002] A wide-body passenger aircraft, with its large takeoff weight, requires a high-bypass turbofan engine. For high-bypass turbofan engines, most of the thrust is generated by the fan, and the huge fan blades are mounted on the fan disk. This necessitates a large-sized fan disk, making it one of the key components of a turbofan engine. The development trend of modern turbofan engine fan disks is to reduce weight while increasing strength, ensuring good toughness and plasticity, which is technically very challenging. Forging technology, due to its unique advantages, has been widely used in various fields such as aerospace. China has put into use large-scale die forging presses such as 800MN and 200MN, meeting the equipment requirements for the preparation of large forgings. These large-sized rotating forgings have been widely used in military and civilian aircraft engines.

[0003] However, the conditions under which fan disc forgings are used determine the complexity of their structure. The integral forming by forging inevitably increases the maximum cross-sectional thickness of the fan disc. The raw material for fan disc forgings is Ti-6Al-4V, and its maximum hardened thickness is about 30mm. However, the maximum cross-sectional thickness of large-size, thick-section fan disc forgings can reach 145mm, which is nearly five times the maximum hardened thickness.

[0004] Traditional large-size variable cross-section integral bladed disk forgings involve two heating processes, primarily: blanking → upsetting → blank machining → final forging. Due to their thick cross-sections, the performance of fan disk forgings produced using traditional methods is insufficient to meet the requirements of high-performance aero-engines, especially at high temperatures. Currently, research on the forming and performance of large-size, thick-section fan disk forgings is limited. Reducing the maximum cross-sectional thickness of fan disk forgings, improving the uniformity of forging deformation, and enhancing forging performance are urgent issues that need to be addressed. Summary of the Invention

[0005] The purpose of this invention is to solve the problem that the forging performance of large-size rear cross-section fan disc forgings is difficult to meet the requirements of high-performance aero engines. This invention provides a method for manufacturing large-size thick cross-section fan disc forgings, which promotes a uniform distribution of the overall deformation of the large-size thick cross-section fan disc forgings, reduces the maximum cross-sectional thickness of the fan disc forgings, and improves the forging performance.

[0006] The technical solution adopted in this invention is: a method for manufacturing large-size, thick-section fan disc forgings, wherein the fan disc forgings are made of Ti-6Al-4V material and the maximum cross-sectional thickness is greater than or equal to 120mm;

[0007] The billet is heated to (T) β -30)℃~(Tβ After reaching -50℃, the blank is transferred to a mold for pressing to form a rough blank; the rough blank is then heated to (T... β -30)℃~(T β After being heated to -50℃, the parts are transferred to the final forging die and pressed into forgings in one heat; the forgings are then air-cooled.

[0008] The final forging die includes an upper die and a lower die. The lower die cavity of the lower die is provided with a lower die boss. The lower die boss includes a top section and a bottom section in the vertical direction. The side wall of the top section is a slope that gradually slopes inward from bottom to top in the radial direction. The side wall of the bottom section is a slope that gradually slopes inward from bottom to top in the radial direction. The slope angle of the bottom section is smaller than that of the top section.

[0009] The center of the forging has an upper groove and a lower groove.

[0010] Furthermore, a fan is used to air-cool the upper and lower grooves of the blow-forged part.

[0011] Furthermore, the inclination of the top segment is 25° to 35°; the inclination of the bottom segment is 3° to 10°.

[0012] Furthermore, the mold cavity of the mold is a frustum shape that gradually increases radially from bottom to top.

[0013] Furthermore, the blank includes a bottom segment located at the bottom of the mold and a top segment located at the top of the mold along the axial direction; the bottom segment is a body of revolution with a diameter that gradually increases from bottom to top, and the generatrix of its rotation surface is a straight line; the top segment is a body of revolution, and the generatrix of its rotation surface is a smooth, outwardly convex arc.

[0014] Furthermore, when the billet is pressed and formed by the final forging die, the top section of the billet is formed in the lower die and the top section is formed in the upper die.

[0015] Furthermore, the following preparatory work should be carried out before forging:

[0016] Based on the structural characteristics of the fan disc parts, the optimal forging blank is first designed according to its shape, and the final forging die is designed based on the optimal forging blank.

[0017] Using full-process numerical simulation technology, the optimal blank shape is designed according to the deformation requirements of the forging, and the die is designed based on the optimal blank shape.

[0018] The final forging mold and the die mold were made.

[0019] Furthermore, the billet is formed by machining vehicle models after the bar stock is cut.

[0020] Furthermore, after the billet is formed, before final forging, the billet needs to be cooled to room temperature before the positioning holes are machined.

[0021] The beneficial effects of this invention are as follows: by using pre-forging to produce the blank, compared with the traditional method of obtaining the blank through post-processing with an upsetting die, it has the following advantages:

[0022] Firstly, the number of forging passes does not increase. During the process from pre-forging billet to forging, the degree of change in the cross-section of the forging is greatly reduced, the amount of deformation increases, and the deformation distribution is more uniform. The effective deformation range is expanded, the deformation dead zone is eliminated, the performance margin of the forging is high, and it is easier to meet the requirements of the integral bladed disk forging in terms of microstructure and performance.

[0023] Secondly, due to the increased deformation and more uniform deformation distribution, the cross-sectional dimensions of the forging blank can be effectively reduced, which helps to save raw materials. Attached Figure Description

[0024] Figure 1 This is a cross-sectional view of the bar billet of the present invention;

[0025] Figure 2 This is a cross-sectional view of the blank of the present invention;

[0026] Figure 3 This is a schematic diagram of the mold for the present invention;

[0027] Figure 4 for Figure 3 Top view;

[0028] Figure 5 This is a cross-sectional view of the forging;

[0029] Figure 6 This is a cross-sectional view of the lower mold;

[0030] Figure 7 This is a schematic diagram of a bar billet being forged in a die.

[0031] Figure 8 A schematic diagram of the blank formed by forging with a die;

[0032] Figure 9 This is a schematic diagram of the forging of a blank in the final forging die;

[0033] Figure 10 This is a schematic diagram of the final forging process to form the forging.

[0034] Figure reference numerals: 1. Bar billet; 2. Bottom segment 2A; 2. Top segment 2B; 2. Positioning hole 2C; 3. Forging; 3. Upper groove 3A; Lower groove 3B; 4. Die; 5. Upper die; 6. Lower die; 6. Lower die boss 6A; Top segment 6A1; Bottom segment 6A2. Detailed Implementation

[0035] The present invention will be further described below with reference to the accompanying drawings:

[0036] Ti-6Al-4V material, with a maximum hardened thickness of approximately 30mm, can be used to produce qualified Ti-6Al-4V fan disc forgings using the traditional upsetting method, especially for thicknesses less than 50mm. However, for forgings with a maximum cross-sectional thickness greater than or equal to 120mm, or even as high as 145mm, the microstructure and properties of the forgings obtained using traditional methods are insufficient to meet the requirements of high-performance aero-engines. To address this issue, this invention discloses a method for manufacturing large-size, thick-section fan disc forgings, wherein the fan disc forging material is Ti-6Al-4V, and the maximum cross-sectional thickness is greater than or equal to 120mm.

[0037] Bar billet 1 heated to (T) β -30)℃~(T β After reaching -50℃, it is transferred to mold 4 for pressing to form blank 2; blank 2 is heated to (T β -30)℃~(T β After being heated to -50℃, the forging is transferred to the final forging die and forged in one pass to form forging 3; forging 3 is then air-cooled. In this invention, the temperature range of both billet preparation and final forging is controlled below the phase transformation point, which controls the content of α and β phases in the high-magnification microstructure, thus helping to ensure the strength and plasticity of the forging.

[0038] The final forging die includes an upper die 5 and a lower die 6, such as Figure 6 As shown, a lower mold boss 6A is provided at the center of the lower mold cavity of the lower mold 6. The lower mold boss 6A includes a top section 6A1 and a bottom section 6A2 in the vertical direction. The side wall of the top section 6A1 is a slope that gradually slopes inward from bottom to top in the radial direction. The side wall of the bottom section 6A2 is a slope that gradually slopes inward from bottom to top in the radial direction. The inclination angle of the bottom section 6A2 is smaller than that of the top section 6A1.

[0039] like Figure 5 As shown, the center of the forging 3 has an upper groove 3A and a lower groove 3B.

[0040] Among them, the top section 6A1 of the lower die boss 6A is mainly used for positioning. By the abrupt change in the slope between the bottom section 6A2 and the top section 6A1, and the fact that the slope angle of the bottom section 6A2 is smaller than that of the top section 6A1, the thickness of the forging section is reduced to the maximum extent, the maximum thickness of the forging is reduced, the uniformity of die forging deformation is improved, and thus the requirements of the forging for its microstructure and performance are improved.

[0041] The forging 3 has an upper groove 3A and a lower groove 3B formed in the center, which increases the deformation range of the forging and reduces the deformation dead zone.

[0042] During the final forging, the forging is produced in one pass, which is highly efficient.

[0043] After final forging, forging 3 was air-cooled, which accelerated the cooling rate and achieved rapid cooling. This accelerated the temperature drop of the core of the thick forging 3, ensuring the α phase content of the forging and thus guaranteeing the core performance. This further ensured the forging's performance requirements in terms of microstructure and properties.

[0044] Preferably, a fan is used to air-cool the upper groove 3A and lower groove 3B of the blow-forged part 3.

[0045] During operation, the forging 3 is placed horizontally, and the fan blows directly onto the upper groove 3A and the lower groove 3B, which improves the cooling speed.

[0046] Practice has shown that, under the same forging conditions, the forging exhibits optimal performance when the inclination of the top section 6A1 is 25°–35° and the inclination of the bottom section 6A2 is 3°–10°. In the embodiment disclosed in the attached drawings, the inclination of the top section 6A1 is 30° and the inclination of the bottom section 6A2 is 7°.

[0047] In order to produce the optimal blank 2 and to keep the structure of the mold 4 as simple as possible, in this invention, as follows: Figure 3 and Figure 4 As shown, the mold cavity of the mold 4 is a frustum shape that gradually increases radially from bottom to top.

[0048] like Figure 2 As shown, the blank 2 includes a bottom segment 2A located at the bottom of the mold 4 and a top segment 2B located at the top of the mold 4 along the axial direction; the bottom segment 2A is a rotating body with a diameter that gradually increases from bottom to top, and the generatrix of its rotating surface is a straight line; the top segment 2B is a rotating body, and the generatrix of its rotating surface is a smooth, outwardly convex arc.

[0049] The special rotating body design of the bottom segment 2A of the blank 2 can better meet the requirements of one-time hot and one-press forming of forgings, making the deformation of each part in the final forging process more uniform, which is more conducive to the forging performance meeting the requirements. Moreover, the outer circumferential allowance of the forging is small, which greatly reduces the subsequent machining allowance and helps to save materials.

[0050] When the blank 2 is pressed and formed by the final forging die, the top segment 2B of the blank 2 is formed in the lower die 6 and the top segment 2B is formed in the upper die 5.

[0051] The following preparations should be made before forging:

[0052] Based on the structural characteristics of the fan disc parts, the optimal forging blank is first designed according to its shape, and the final forging mold is designed based on the optimal forging blank. Using full-process numerical simulation technology, the optimal blank shape is designed according to the deformation requirements of the forging, and the die 4 is designed based on the optimal blank shape. The final forging mold and the die 4 are then manufactured.

[0053] Based on the shape and size of the fan disc parts, the optimal forging is designed according to the shape. Using digital simulation technology, the optimal blank shape is repeatedly optimized and designed. Based on this, the die 4 and the final forging die are designed, which promotes the uniform distribution of the overall deformation of the fan disc forging during the entire forging process, which is conducive to improving the performance of the forging.

[0054] In the process of mold design, based on the material's requirements for deformation, and combined with numerical simulation technology, the local characteristics of the theoretical blank and the theoretical forging blank are adjusted. This can increase the amount of deformation while achieving a uniform distribution of deformation, thus eliminating the deformation dead zone.

[0055] The entire forging process is as follows Figure 7 , Figure 8 , Figure 9 and Figure 10 The process is as follows, proceeding in the order shown:

[0056] like Figure 1 The billet 1 shown is formed by machining a vehicle model after blanking. After blanking, the billet 1 undergoes vehicle model machining, resulting in a chamfer at its bottom end. The chamfer's angle is the same as the angle of the inner wall of the mold cavity of the die 4, and the dimensions of the bottom surface of the billet 1 match the dimensions of the bottom surface of the mold cavity of the die 4. This facilitates the positioning of the billet 1 within the die 4, ensuring smooth die forging. Only one end of the billet needs chamfering after blanking, making the process simple and easy.

[0057] After forming the blank 2, before final forging, the blank 2 needs to be cooled to room temperature before machining the positioning hole 2C. The positioning hole 2C is machined at the center of the end face of the top segment 2B of the blank 2. Its shape and size are adapted to the top segment 6A1 of the lower die boss 6A, which facilitates the positioning of the blank 2 in the lower die 6 and ensures the smooth progress of the final forging. During the forging process, an 800MN die forging press can be used.

[0058] The fan disc forgings produced by the method for manufacturing large-size thick-section fan discs disclosed in this invention have uniform burr distribution, no forging defects, and excellent microstructure. The high-temperature yield strength at 300℃ is increased from 510MPa to 570MPa, and the high-temperature tensile strength at 300℃ is increased from 640MPa to 700MPa, meeting the performance requirements of the model.

Claims

1. A method for manufacturing large-size, thick-section fan disc forgings, characterized in that: The fan disc forging is made of Ti-6Al-4V, and the maximum cross-sectional thickness is greater than or equal to 120mm. The billet (1) is heated to (T) β -30)℃~(T β After reaching -50℃, it is transferred to the mold (4) for pressing to form a blank (2); the blank (2) is heated to (T β -30)℃~(T β After being heated to -50℃, the forging is transferred to the final forging die and forged into a forging (3) in one pass; and the forging (3) is then air-cooled. The final forging die includes an upper die (5) and a lower die (6). The lower die (6) has a lower die boss (6A) at the center of its lower die cavity. The lower die boss (6A) includes a top section (6A1) and a bottom section (6A2) in the vertical direction. The side wall of the top section (6A1) is a slope that gradually slopes inward from bottom to top in the radial direction. The side wall of the bottom section (6A2) is a slope that gradually slopes inward from bottom to top in the radial direction. The inclination angle of the bottom section (6A2) is smaller than that of the top section (6A1). The center of the forging (3) has an upper groove (3A) and a lower groove (3B); The inclination of the top section (6A1) is 25° to 35°; the inclination of the bottom section (6A2) is 3° to 10°.

2. The method for manufacturing large-size, thick-section fan disc forgings as described in claim 1, characterized in that: A fan is used to air cool the upper groove (3A) and lower groove (3B) of the blow-forged part (3).

3. The method for manufacturing large-size, thick-section fan disc forgings as described in claim 1 or 2, characterized in that: The mold cavity of the mold (4) is a frustum shape that gradually increases radially from bottom to top.

4. The method for manufacturing large-size, thick-section fan disc forgings as described in claim 1 or 2, characterized in that: The blank (2) includes a bottom segment (2A) located at the bottom of the mold (4) and a top segment (2B) located at the top of the mold (4) along the axial direction; the bottom segment (2A) is a rotating body with a diameter that gradually increases from bottom to top, and the generatrix of its rotating surface is a straight line; the top segment (2B) is a rotating body, and the generatrix of its rotating surface is a smooth, outwardly convex arc.

5. The method for manufacturing large-size, thick-section fan disc forgings as described in claim 4, characterized in that: When the blank (2) is pressed and formed by the final forging die, the top segment (2B) of the blank (2) is formed in the lower die (6) and the top segment (2B) is formed in the upper die (5).

6. The method for manufacturing a large-size, thick-section fan disc forging as described in claim 1, characterized in that: The following preparations should be made before forging: Based on the structural characteristics of the fan disc parts, the optimal forging blank is first designed according to its shape, and the final forging die is designed based on the optimal forging blank. Using full-process numerical simulation technology, the optimal blank shape is designed according to the deformation requirements of the forging, and the die is designed according to the optimal blank shape (4). The final forging mold and the die mold were made (4).

7. The method for manufacturing a large-size, thick-section fan disc forging as described in claim 1, characterized in that: The billet (1) is formed by cutting bar stock and then processing it into vehicle models.

8. The method for manufacturing a large-size, thick-section fan disc forging as described in claim 1, characterized in that: After forming the blank (2), before final forging, the blank (2) needs to be cooled to room temperature before machining the positioning hole (2C).

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