Disk shaft and its manufacturing method

Abstract

The present invention discloses a manufacturing method of a disk shaft. The disk shaft includes a journal and a disk, and the journal and the disk are integrally formed and made of titanium alloy. The manufacturing method includes: Step S1, isothermal upsetting of a titanium alloy bar to obtain a round cake-shaped workpiece; Step S2, pre-forging the workpiece to obtain an intermediate piece; Step S3, final forging the intermediate piece to obtain the disk shaft, and for the journal part of the disk shaft, it is formed by backward extrusion; wherein, Step S1 is not carried out in a mold, and Steps S2 and S3 are carried out in a mold. The disk shaft and its manufacturing method utilize one-time isothermal upsetting and two-time die forging to form an integrally formed disk shaft, making the part have strong integrity, avoiding the connection performance defects of inertia friction welding or bolt connection, having a longer part life, and being easier to process at the same time.

Description

Technical Field

[0001] The present invention provides a disk shaft and a manufacturing method thereof. Background Art

[0002] The large passenger aircraft engine is a typical high-bypass turbofan engine. Compared with the large transport aircraft engine, the large passenger aircraft engine has requirements for longer life and higher reliability. The high-pressure compressor disk is one of the key cold-end components of the large passenger aircraft engine. According to airworthiness requirements, it should be able to be safely used under the condition of full decay while reaching the red-line temperature and red-line speed. Titanium alloy is commonly used in large cross-section and high-load components such as fans and compressor disks. The first four stages of the high-pressure compressor front disk of the large passenger aircraft engine usually adopt titanium alloy materials.

[0003] At the present stage, the various disk components of the high-pressure compressor adopt the scheme of inertia friction welding or bolt connection. The bolt connection scheme of each disk component will increase the fretting wear at the connection, reducing the service life of the disk component. For the two-stage compressor disk components welded by inertia friction welding, the main processes are generally: forging - heat treatment - rough machining - non-destructive testing - welding - heat treatment - non-destructive testing - machining into parts. Since inertia friction welding will generate large residual stresses in the weld and heat-affected zone, and the machining difficulty after welding also increases, the whole process takes a long time and has a high cost.

[0004] In addition, in the welding performance of titanium alloy, the crack propagation performance of the joint is much worse than that of the base material, and the impact performance is only half of that of the base material. There are problems such as poor fracture toughness of the material in the heat-affected zone and accelerated crack propagation in alloy welding, which cannot meet the design requirements. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the defects in the prior art that the connection performance of the disk components welded by inertia friction welding or bolt connection is poor, the processing difficulty is high, and the part life is short, and to provide a disk shaft and a manufacturing method thereof.

[0006] The present invention solves the above technical problem through the following technical solutions:

[0007] A manufacturing method of a disk shaft, the disk shaft includes a journal and a disk, the journal and the disk are integrally formed and made of titanium alloy, and the manufacturing method includes:

[0008] Step S1: Isothermal upsetting the titanium alloy bar to obtain a round cake-shaped workpiece;

[0009] Step S2: Pre-forging the workpiece to obtain an intermediate part;

[0010] Step S3: Finish-forging the intermediate part to obtain a disk shaft, and for the journal part of the disk shaft, it is formed by backward extrusion;

[0011] Among them, step S1 is not carried out in the mold, and steps S2 and S3 are carried out in the mold.

[0012] In the present invention, through the above method, by using one-time isothermal upsetting and two-time die forging to form an integrally formed disk shaft, the integrity of the part is strong, avoiding the connection performance defects of inertia friction welding or bolt connection, the part has a longer service life, and is easier to process at the same time.

[0013] Preferably, in step S3, the reverse extrusion forming direction of the journal part of the disk shaft is opposite to the forging direction.

[0014] In the present invention, through the above method, the way of contact between the mold and the intermediate part during the forging process is more conducive to the reverse extrusion forming of the journal part.

[0015] Preferably, in step S1, the isothermal upsetting temperature is always within the two-phase region temperature range.

[0016] Preferably, in step S2, the pre-forging temperature is always within the two-phase region temperature range.

[0017] Preferably, in step S3, the final forging temperature is always higher than the β phase transformation point temperature T β .

[0018] Preferably, the manufacturing method further includes:

[0019] Step S4: successively perform solution treatment and aging treatment on the disk shaft.

[0020] Preferably, the manufacturing method further includes:

[0021] In step S4, the temperature range of the solution treatment is 770°C - 820°C, and the time of the solution treatment is at least 2 hours.

[0022] In step S4, the temperature range of the aging treatment is 600°C - 650°C, and the time of the aging treatment is at least 6 hours.

[0023] In the present invention, through the above method, the microstructure inside the disk shaft is more uniform, and the overall mechanical properties are better.

[0024] Preferably, in step S3, the final forging deformation amount in all regions is greater than or equal to 70%.

[0025] In the present invention, through the above method, the plastic deformation of the disk shaft is uniform and in place, thereby ensuring that the disk shaft as a whole has a uniform microstructure and good mechanical properties.

[0026] A disk shaft, the disk shaft and the wheel disk are integrally formed and made of titanium alloy, and the disk shaft is made by the manufacturing method of the disk shaft as described above.

[0027] In the present invention, the disk shaft manufactured by the above method has low processing difficulty, good connection performance, and a longer part life.

[0028] The positive and progressive effects of the present invention are as follows: The disk shaft and its manufacturing method utilize one-time isothermal upsetting and two-time die forging to form an integrally formed disk shaft, which makes the part have strong integrity, avoids the connection performance defects of inertia friction welding or bolt connection, has a longer part life, and is easier to process. Brief Description of the Drawings

[0029] Figure 1 It is a flowchart of the manufacturing method of the disk shaft in a preferred embodiment of the present invention.

[0030] Figure 2 It is a schematic cross-sectional shape diagram of the pre-forging die of the disk shaft in a preferred embodiment of the present invention.

[0031] Figure 3 It is a schematic cross-sectional shape diagram of the final-forging die of the disk shaft in a preferred embodiment of the present invention.

[0032] Figure 4 It is a comparative analysis diagram of the microstructures of key regions of the integrally forged disk shaft and the single-stage disk part in a preferred embodiment of the present invention.

[0033] Figure 5 It is a schematic diagram of the microstructure at the journal of the integrally forged disk shaft in a preferred embodiment of the present invention.

[0034] Description of the Reference Numerals:

[0035] Pre-forging die 101

[0036] Final-forging die 102

[0037] Workpiece 103

[0038] Intermediate piece 104

[0039] First-stage disk shaft journal 1

[0040] First-stage disk shaft blade 2

[0041] First-stage disk shaft drum 3

[0042] First-stage disk shaft flange 4

[0043] First-stage disk shaft web 5

[0044] First-stage disk shaft drum 6 Detailed Description of the Embodiments

[0045] The present invention will be further described below by way of examples, but the present invention is not limited to the scope of the described examples.

[0046] As Figures 1-3 shown, this embodiment provides a disk shaft and a manufacturing method thereof. In this embodiment, for the disk shaft made of Ti17 titanium alloy material, a forging process of upsetting, pre-forging, and final forging is directly adopted, so that the deformation of each region is uniform, the minimum deformation amount reaches at least 70%, the maximum strain and the highest temperature are well controlled, and the risk of forming recrystallized structure is reduced.

[0047] In this embodiment, the difference between upsetting and pre-forging is that in upsetting, an isothermal upsetting is used to upset the Ti17 titanium alloy bar into a workpiece 103 with a round cake shape, while in pre-forging, the round cake-shaped workpiece 103 is placed in a pre-forging die 101 and forged into an intermediate piece 104 with a certain shape. Among them, the pre-forging die 101 can restrict the material flow and make the forging deformation more uniform. The shape of the intermediate piece 104 is obtained through simulation calculation, which is more conducive to the overall forming of the disk shaft in the final forging.

[0048] In this embodiment, the front journal of the compressor and the first-stage blisk are integrally forged through the following steps to form an integrally forged disk shaft:

[0049] 1. Cut the Ti17 bar with a diameter of Φ300 and a length of 930 mm.

[0050] 2. After the blank is machined and the end face is corroded, select the two-phase region temperature Tβ - 30°C for upsetting, and upset it to a diameter of about Φ385 and a height of 560 mm, and the deformation amount is about 40%.

[0051] 3. Select the two-phase region temperature Tβ - 30°C for one-fire pre-forging, to a diameter of about Φ520 and a height of 370 mm, and the deformation amount is about 35%; machine the rough shape to remove the burrs.

[0052] 4. Select the temperature Tβ + 30°C above the phase transformation point for one-fire final forging. The material of the final forging die 102 is selected as H13. The journal part is obtained by backward extrusion.

[0053] 5. The heat treatment system is: solution heating temperature 800°C, holding time 240 min; aging heating temperature 630°C, holding time 480 min.

[0054] In this embodiment, the comparative analysis of the mechanical properties of the integrally forged disk shaft and the single-stage disk in the three key regions of the blade, web, and hub is shown in Table 1.

[0055]

[0056] Table 1 Comparative analysis of the mechanical properties of the integrally forged disk shaft and the single-stage disk

[0057] Among them, for the tensile properties in the chordwise direction of the blade part and the chordwise direction of the hub part, the two are very close; for the fracture toughness at the web position, the fracture toughness of the integrally forged disk shaft is slightly higher than that of the single-stage disk part; the strength at the radial position of the blade of the single-stage disk part is slightly higher than that of the integrally forged disk shaft, while the strength at the chordwise position of the web of the integrally forged disk shaft is slightly higher than that of the single-stage disk part.

[0058] It can be seen from this that the mechanical properties of both meet the design performance requirements, which also shows that the mechanical properties of the integrally forged disk shaft can meet the design requirements.

[0059] In this embodiment, the comparative analysis of the microstructures of the key areas of the integrally forged disk shaft and the single-stage disk part is as Figure 4 shown, which are the microstructures of the three key areas of the blade, the web and the hub respectively. The microstructures of the integrally forged disk shaft and the single-stage disk part are the same and both meet the design performance requirements.

[0060] For the chordwise and axial room-temperature tensile properties at the journal of the integrally forged disk shaft (as shown in Table 1), they are both close to the room-temperature tensile properties at other positions (blade, web, hub), meeting the design requirements.

[0061] The microstructure at the journal of the integrally forged disk shaft is as Figure 5 shown. Its structure is uniform, the α-phase is well woven, and the microstructure morphology is the same as that at the hub, also meeting the design performance requirements.

[0062] Although the specific implementation manners of the present invention have been described above, those skilled in the art should understand that this is only for illustration. The protection scope of the present invention is defined by the appended claims. Without departing from the principles and essence of the present invention, those skilled in the art can make various changes or modifications to these implementation manners, but these changes and modifications all fall within the protection scope of the present invention.

Claims

1. A manufacturing method of a disk shaft, the disk shaft comprising a journal and a bladed disk, characterized in that, The journal and the blisk are integrally formed and made of titanium alloy. The manufacturing method includes: Step S1: Perform an isothermal upsetting on a titanium alloy bar to obtain a round cake-shaped workpiece. Among them, the isothermal upsetting temperature is always within the two-phase region temperature range; Step S2: Perform pre-forging on the workpiece to obtain an intermediate part; Step S3: Perform final forging on the intermediate part to obtain a disk shaft. For the journal part of the disk shaft, it is formed by backward extrusion; Among them, Step S1 is not carried out in a mold, and Steps S2 and S3 are carried out in a mold.

2. The manufacturing method of the disk shaft according to claim 1, characterized in that: In Step S3, the backward extrusion forming direction of the journal part of the disk shaft is opposite to the forging direction.

3. The manufacturing method of the disk shaft according to claim 1, characterized in that: In Step S2, the pre-forging temperature is always within the two-phase region temperature range.

4. The manufacturing method of the disk shaft according to claim 1, characterized in that: In Step S3, the final forging temperature is always higher than the β phase transformation point temperature Tβ.

5. The manufacturing method of the disk shaft according to claim 1, characterized in that The manufacturing method further includes: Step S4: Perform solution treatment and aging treatment on the disk shaft in sequence.

6. The manufacturing method of the disk shaft according to claim 5, characterized in that: In Step S4, the temperature range of the solution treatment is 770°C - 820°C, and the time of the solution treatment is at least 2 hours.

7. The manufacturing method of the disk shaft according to claim 5, characterized in that: In Step S4, the temperature range of the aging treatment is 600°C - 650°C, and the time of the aging treatment is at least 6 hours.

8. The manufacturing method of the disk shaft according to claim 1, characterized in that: In Step S3, the final forging deformation amount in all regions is greater than or equal to 70%.

9. A disc shaft, characterized in that, The disk shaft and the disk are integrally formed and made of titanium alloy. The disk shaft is made by the manufacturing method of the disk shaft according to any one of claims 1 - 8.

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