Controllable strain isothermal die forging forming die and method for double-structure titanium alloy bladed disc

Abstract

The invention discloses a controllable strain isothermal die forging forming die and method for a double-structure titanium alloy bladed disc, the forming die comprises a bladed disc prefabricated blank, an upper female die, a lower female die and a plurality of groups of male dies, and each group of male dies comprises an upper male die and a lower male die; forming grooves are formed in the upper female die and the lower female die; according to the forming method, the two forming grooves, the upper male die and the lower male die are buckled to define a forming cavity used for containing a blade disc prefabricated blank, and the formed blade disc is obtained after the blade disc prefabricated blank in the forming cavity is subjected to controllable strain isothermal die forging. Gradient double-structure / double-performance distribution of a wheel disc part equiaxed structure, a blade part mesh basket structure and a connecting part gradually-changed transition structure in the diameter direction of the formed blade disc can be achieved, and therefore the service performance of blade disc parts is improved, and the service life of the blade disc parts is prolonged.

Description

Technical Field

[0001] The present invention relates to the technical field of titanium alloy materials, and in particular to a controllable strain isothermal forging die and method for a dual-structure titanium alloy blade disk. Background Art

[0002] The problem of difficulty in balancing the performance of blades and disc of conventional homogeneous / single-performance titanium alloy integral impeller is very prominent. The dual-structure distribution inside the impeller, with equiaxial structure in the disc part, basket structure in the blade part, and gradual transition structure along the diameter direction in the connection part, is an ideal way to solve the problem of difficulty in balancing the performance of impeller blades and disc.

[0003] Isothermal die forging includes conventional isothermal die forging and controlled strain isothermal die forging (which can be achieved through a combination of multiple dies). It is a forming method that realizes the plastic forming of parts by isothermal hot plastic flow of metal in the die. During controlled strain isothermal die forging, the controllable strain deformation of the impeller preform disc part can be effectively deformed by the punch, the blade part is not effectively deformed, and the connection part is gradually deformed along the diameter direction, so that the α+β basket tissue of the disc part is fully globalized, the blade part is not spheroidized, and the connection part is gradually spheroidized along the diameter direction, thereby realizing the gradient dual tissue distribution of the equiaxial tissue of the impeller disc part, the basket tissue of the blade part, and the gradual transition tissue of the connection part along the diameter direction, which provides a new method for the development of dual-tissue titanium alloy impellers. Summary of the invention

[0004] The purpose of the present invention is to solve the technical problems existing in the prior art and to provide a controllable strain isothermal forging die and method for a dual-structure titanium alloy blade disk.

[0005] To achieve the above-mentioned purpose, the technical solution provided by the present invention is: a controllable strain isothermal forging forming die for a dual-structure titanium alloy blade disk, the forming die comprising a blade disk preform, an upper concave die, a lower concave die and a plurality of groups of convex dies, each group of convex dies comprising an upper convex die and a lower convex die; the upper concave die and the lower concave die are both provided with forming grooves; the two forming grooves, the upper convex die and the lower convex die are buckled together to form a forming cavity for placing the blade disk preform, and the blade disk preform in the forming cavity is subjected to controllable strain isothermal forging to obtain a formed blade disk;

[0006] The formed blade disk includes a connecting part, a disk part and a blade part. The thickness of the disk part is smaller than that of the blade part and the connecting part. The shapes of the connecting part, the blade part and the disk part are gradually transitioned. The upper punch and the lower punch are respectively provided with an upper punch gradient transition zone and a lower punch gradient transition zone. The widths of the upper punch gradient transition zone and the lower punch gradient transition zone correspond to the gradient widths of the connecting part and the blade part, so as to control the shapes of the disk part, the connecting part and the blade part of the formed blade disk.

[0007] Preferably, the blisk preform includes a preform wheel disc portion and a preform blade portion. The blisk preform is disc-shaped with the preform wheel disc portion in the middle protruding. The thickness and diameter length of the preform blade portion are respectively equal to the thickness and diameter length of the blade portion.

[0008] Preferably, the microstructures of the preform wheel disc and the preform blades are basket structures.

[0009] Preferably, an upper punch having an upper punch gradient transition zone and a lower punch having a lower punch gradient transition zone are squeezed into the forming cavity through the through holes on the upper die and the lower die under the drive of an external hydraulic device, and are used for controllable strain isothermal forging of the blade disk preform.

[0010] Preferably, the shapes of the forming groove and the upper and lower dies are symmetrical, and the upper and lower dies are respectively provided with through holes that cooperate with the upper and lower punches for movement. The through holes are connected to the forming cavity and the outside world, and the diameter of the through holes is equal to the diameter of the upper and lower punches.

[0011] The present invention also discloses a forming method of the controllable strain isothermal forging die of the dual-structure titanium alloy blade disk described above, the forming method comprising the following steps:

[0012] S1: Pre-forging a blisk preform from a titanium alloy by a near-β forging method, wherein the preform wheel disc portion of the blisk preform has different initial heights, and the preform wheel disc portion and the preform blade portion of the blisk preform have a basket structure inside;

[0013] S2: The preform of the blade disk preformed in S1 is buckled into a forming cavity surrounded by two forming grooves, an upper punch and a lower punch for controlled strain isothermal die forging;

[0014] S3: The upper punch and the lower punch are driven by an external hydraulic device to squeeze into the forming cavity through the through holes on the upper die and the lower die. At a specific temperature, the upper punch and the lower punch isothermally extrude the preform disc part to a preset thickness at the same extrusion rate. During the die forging process, the basket tissue of the preform disc part is completely spheroidized to form an equiaxial tissue, and the preform blade part does not spheroidize and retains the basket tissue; the connection between the preform disc part and the preform blade part is gradually spheroidized along the diameter direction to form a gradual transition tissue, and finally a formed blade disk is obtained. The equiaxial tissue of the disc part, the basket tissue of the blade part and the gradual transition tissue of the connection part of the formed blade disk show a gradient double tissue / double performance distribution.

[0015] Preferably, the die forging temperature in the controlled strain isothermal die forging in S3 is in the range of 700-880° C., and the radial movement rate of the upper punch and the lower punch is in the range of 0.05-0.4 mm / min.

[0016] Beneficial effects of the present invention:

[0017] In the die forging process of the present invention, the basket structure of the preform disc part is completely spheroidized to form an equiaxial structure, and the preform blade part does not spheroidize and retains the basket structure; the connection between the preform disc part and the preform blade part is gradually spheroidized along the diameter direction to form a gradual transition structure, which can achieve a gradient double structure / double performance distribution of the equiaxial structure of the disc part, the basket structure of the blade part and the gradual transition structure of the connection part along the diameter direction of the formed blade disc, thereby improving the service performance and service life of the blade disc parts. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The drawings described herein are used to provide further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0019] Figure 1 It is the initial basketweave structure of the TC18 titanium alloy in the present invention.

[0020] Figure 2 is a cross-sectional view of the controllable strain isothermal forging die of the present invention;

[0021] Figure 3 It is a schematic diagram of the blade disk preform in the present invention;

[0022] Figure 4 Schematic diagram of the shaped blade disk of the present invention.

[0023] Figure annotation:

[0024] 1-upper punch, 2-lower punch, 3-upper punch gradient transition zone, 4-lower punch gradient transition zone, 5-upper die, 6-forming cavity, 7-blade disk preform, 8-lower die, 9-through hole, 10-preform blade part, 11-connecting part, 12-wheel disk part, 13-blade part, 14-preform wheel disk part. DETAILED DESCRIPTION

[0025] This section will describe in detail the specific embodiments of the present invention. The preferred embodiments of the present invention are shown in the accompanying drawings. The purpose of the accompanying drawings is to supplement the description of the text part of the specification with graphics, so that people can intuitively and vividly understand each technical feature and the overall technical solution of the present invention, but it cannot be understood as a limitation on the scope of protection of the present invention.

[0026] In the description of the present invention, it should be understood that descriptions involving orientations, such as up, down, front, back, left, right, etc., and orientations or positional relationships indicated are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0027] In the description of the present invention, "several" means one or more, "more" means more than two, "greater than", "less than", "exceed" etc. are understood as not including the number itself, and "above", "below", "within" etc. are understood as including the number itself. If there is a description of "first" or "second", it is only used for the purpose of distinguishing the technical features, and cannot be understood as indicating or implying the relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0028] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, connecting, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0029] Reference Figure 1-Figure 4 The preferred embodiment of the present invention is a controllable strain isothermal forging forming die for a dual-structure titanium alloy blade disk, the forming die comprises a blade disk preform 7, an upper die 5, a lower die 8 and a plurality of groups of punches, each group of punches comprises an upper punch 1 and a lower punch 2; the upper die 5 and the lower die 8 are both provided with forming grooves; the two forming grooves, the upper punch 1 and the lower punch 2 are buckled together to form a forming cavity 6 for placing the blade disk preform 7, and the blade disk preform 7 in the forming cavity 6 is formed by controlled strain isothermal forging to obtain a formed blade disk;

[0030] The formed blade disk includes a connecting portion 11, a disk portion 12, and a blade portion 13. The thickness of the disk portion 12 is smaller than that of the blade portion 13 and the connecting portion 13. The shapes of the connecting portion 13, the blade portion 11 and the disk portion 12 are gradually transitioned. The upper punch 1 and the lower punch 2 are respectively provided with an upper punch gradient transition zone 3 and a lower punch gradient transition zone 4. The widths of the upper punch gradient transition zone 3 and the lower punch gradient transition zone 4 correspond to the gradient widths of the connecting portion 11 and the blade portion 13, and are used to control the shapes of the disk portion 12, the connecting portion 11 and the blade portion 13 of the formed blade disk.

[0031] Specifically, the widths of the upper punch gradient transition zone 3 and the lower punch gradient transition zone 4 are based on the gradient widths of the connection portion 11 and the blade portion 13 of the formed blisk to be actually produced.

[0032] Furthermore, the blisk preform 7 includes a preform wheel disc portion 14 and a preform blade portion 10. The blisk preform 7 has a disc-like shape with the preform wheel disc portion 14 in the middle protruding. The thickness and diameter length of the preform blade portion 10 are respectively equal to the thickness and diameter length of the blade portion 13.

[0033] Furthermore, the microstructures of the preform wheel disc portion 14 and the preform blade portion 10 are both basket structures.

[0034] Furthermore, the upper punch 1 having the upper punch gradient transition zone 3 and the lower punch 2 having the lower punch gradient transition zone 4 are squeezed into the forming cavity 6 through the through holes on the upper die 5 and the lower die 8 under the drive of an external hydraulic device, and are used for controllable strain isothermal forging of the blade disk preform 7.

[0035] Furthermore, the shapes of the forming groove and the upper and lower dies 5 and 8 are symmetrical. The upper and lower dies 5 and 8 are respectively provided with through holes 9 that cooperate with the upper punch 1 and the lower punch 2 for movement. The through holes 9 are connected to the forming cavity 6 and the outside world, and the diameter of the through holes 9 is equal to the diameter of the upper and lower punches 1 and 2.

[0036] The present invention provides a forming method of a dual-structure titanium alloy blade disk using the controllable strain isothermal forging die described above, the forming method comprising the following steps:

[0037] S1: pre-forging a blisk preform 7 from a titanium alloy by a near-β forging method, wherein a preform wheel disc portion 14 in the blisk preform 7 has different initial heights, and the preform wheel disc portion 14 and the preform blade portion 10 in the blisk preform 7 have a basket structure inside;

[0038] S2: The preform 7 of the blisk preformed in S1 is buckled into the forming cavity 6 formed by the two forming grooves, the upper punch 1 and the lower punch 2 for controlled strain isothermal die forging;

[0039] S3: The upper punch 1 and the lower punch 2 are driven by an external hydraulic device to squeeze into the forming cavity 6 through the through holes on the upper die 5 and the lower die 8. At a specific temperature, the upper punch 1 and the lower punch 2 isothermally extrude the preform wheel disc part 14 to a preset thickness at the same extrusion rate. During the die forging process, the basket tissue of the preform wheel disc part 14 is completely spheroidized to form an equiaxial tissue, and the preform blade part 10 does not spheroidize and retains the basket tissue; the connection between the preform wheel disc part 14 and the preform blade part 10 is gradually spheroidized along the diameter direction to form a gradual transition tissue, and finally a formed blade disk is obtained. The equiaxial tissue of the wheel disc part 12, the basket tissue of the blade part 13 and the gradual transition tissue of the connection part 11 of the formed blade disk present a gradient dual tissue / dual performance distribution.

[0040] Furthermore, the die forging temperature in the controlled strain isothermal die forging in S3 is in the range of 700-880° C., and the radial movement rate of the upper punch 1 and the lower punch 2 is in the range of 0.05-0.4 mm / min.

[0041] In the die forging process of the present invention, the basket structure of the preform disc part 14 is completely spheroidized to form an equiaxial structure, and the preform blade part 10 does not undergo spheroidization and retains the basket structure; the connection between the preform disc part 14 and the preform blade part 10 is gradually spheroidized along the diameter direction to form a gradual transition structure, which can achieve a gradient double structure / double performance distribution of the equiaxial structure of the disc part 12, the basket structure of the blade part 13 and the gradual transition structure of the connection part 11 along the diameter direction of the formed blade disk, thereby improving the service performance and service life of the blade disk parts.

[0042] Example 1

[0043] The present embodiment provides a controlled strain isothermal forging forming method of a dual-structure titanium alloy blade disk, using the controlled strain isothermal forging forming die of the dual-structure titanium alloy blade disk in the present invention, a blade disk preform 7 with a basket structure inside the preform wheel disk part 14 and the preform blade part 10 is buckled into a forming cavity 6, an upper punch 1 is installed in a through hole 9 of an upper die 5, and a lower punch 2 is installed in a through hole 9 of a lower die 8; the controlled strain isothermal forging die and the blade disk preform 7 are heated to 700-880°C and kept warm for 10 minutes, and the upper punch 1 and the lower punch 2 are pressed at the same pressing rate of 0.05-0.4 mm / min to form the blade disk. The preform 7 is extruded to a preset position, during the extrusion process, the basket tissue of the preform disc part 14 is completely spheroidized to form an equiaxial tissue, the preform blade part 10 does not spheroidize and retains the basket tissue, and the connection between the preform disc part 14 and the preform blade part 10 is gradually spheroidized along the diameter direction to form a gradual transition tissue, and finally a formed blade disk is obtained, and the formed blade disk forms an equiaxial tissue of the disc part 12, a basket tissue of the blade part 13 and a gradient transition tissue of the connection part 11 along the diameter direction. The upper punch 1 and the lower punch 2 are taken out, the upper die 5 and the lower die 8 are separated, and the formed blade disk is taken out.

[0044] After taking out the formed blade disk, since excess metal will enter the flash groove to form burrs during the controlled strain isothermal forging process, it is necessary to remove the burrs of the formed titanium alloy blade disk so that the part shape meets the requirements.

[0045] In this embodiment, the heating for the controlled strain isothermal forging process is provided by an external heating and insulation device to ensure that the forging die and the blade disk preform 7 are isothermally forged at a temperature of 700-880°C, which can be heated by an air furnace or a vacuum furnace (this technical means is a conventional and mature technical means in this technical field, so it will not be described in detail).

[0046] In this embodiment, the power source of the snap-fitting force between the upper die 5 and the lower die 8 in the present invention includes but is not limited to the following power sources. The snap-fitting force between the upper die 5 and the lower die 8 is provided by an external hydraulic element to ensure the contact between the upper die 5 and the lower die 8 to form a stable forming cavity 6, and the snap-fitting force can also be provided by a pin locking device (the technical means of providing the power source by an external hydraulic element and providing the snap-fitting force by a pin locking device are conventional and mature prior arts in the technical field, and therefore will not be described in detail).

[0047] In this embodiment, the upper punch 1 and the lower punch 2 radially extrude the blisk preform 7 driven by an external hydraulic element, and the extrusion rate and extrusion stroke position of the upper punch 1 and the lower punch 2 are both achieved by an external stroke control device.

[0048] Preferably, the extrusion power of the upper punch 1 and the lower punch 2 includes but is not limited to being provided by an external hydraulic element, as long as the upper punch 1 and the lower punch 2 can be driven to extrude the blisk preform 7;

[0049] Furthermore, the extrusion stroke position of the upper punch 1 and the lower punch 2 includes but is not limited to being controlled by a stroke control device, as long as the upper punch 1 and the lower punch 2 can be extruded to a preset position.

[0050] It is understandable that the external hydraulic components, stroke control devices, etc. are conventional and mature prior arts in the technical field, and therefore will not be described in detail.

[0051] In this embodiment, the height of the preform wheel disc part 14 affects the degree of spheroidization of the basket structure of the wheel disc part 12 after the blade disk is formed. The height of the preform wheel disc part 14 in the present invention is set appropriately according to the principle of constant volume, as long as the globalization of the basket structure of the preform wheel disc part 14 can be achieved.

[0052] It is worth noting that the present invention aims to provide a controlled strain isothermal forging forming die for a dual-structure titanium alloy blade disk and a method for producing dual-structure titanium alloy blade disk components using the forming die. Therefore, only the forming aspect of the dual-structure titanium alloy blade disk is described. In actual forming, while adopting the die and forming method, the same specification mold frame and other forming auxiliary equipment familiar to technical personnel in this field should be selected according to specific use requirements.

[0053] Under the premise that no conflict occurs, those skilled in the art may freely combine and superimpose the above-mentioned additional technical features.

[0054] The above description is only a preferred implementation mode of the present invention. Any technical solution that achieves the purpose of the present invention by substantially the same means belongs to the protection scope of the present invention.

Claims

1. A controllable strain isothermal forging die for a dual-structure titanium alloy blade disk, characterized in that: The forming die comprises a blade disk preform (7), an upper concave die (5), a lower concave die (8) and a plurality of groups of convex dies, each group of convex dies comprising an upper convex die (1) and a lower convex die (2); the upper concave die (5) and the lower concave die (8) are both provided with forming grooves; the two forming grooves, the upper convex die (1) and the lower convex die (2) are buckled together to form a forming cavity (6) for placing the blade disk preform (7); the blade disk preform (7) in the forming cavity (6) is subjected to controllable strain isothermal die forging to obtain a formed blade disk; The formed blade disk comprises a connection part (11), a wheel disk part (12), and a blade part (13); the thickness of the wheel disk part (12) is smaller than the thickness of the blade part (13) and the connection part (13); the shapes of the connection part (13), the blade part (11) and the wheel disk part (12) are gradually transitioned; the upper punch (1) and the lower punch (2) are respectively provided with an upper punch gradient transition zone (3) and a lower punch gradient transition zone (4); the widths of the upper punch gradient transition zone (3) and the lower punch gradient transition zone (4) correspond to the gradient widths of the connection part (11) and the blade part (13), and are used to control the shapes of the wheel disk part (12), the connection part (11) and the blade part (13) of the formed blade disk.

2. The controllable strain isothermal forging die for a dual-structure titanium alloy blade disk according to claim 1, characterized in that: The blade disk preform (7) comprises a preform wheel disk part (14) and a preform blade part (10). The outer shape of the blade disk preform (7) is a raised disc shape of the middle preform wheel disk part (14). The thickness and diameter length of the preform blade part (10) are respectively equal to the thickness and diameter length of the blade part (13).

3. The controllable strain isothermal forging die for a dual-structure titanium alloy blade disk according to claim 2, characterized in that: The microstructures of the preform wheel disc part (14) and the preform blade part (10) are both basket structures.

4. The controllable strain isothermal forging die for a dual-structure titanium alloy blade disk according to claim 3, characterized in that: An upper punch (1) having an upper punch gradient transition zone (3) and a lower punch (2) having a lower punch gradient transition zone (4) are driven by an external hydraulic device to be squeezed into a forming cavity (6) through through holes on an upper die (5) and a lower die (8) for controllable strain isothermal die forging of a blade disk preform (7).

5. The controllable strain isothermal forging die for a dual-structure titanium alloy blade disk according to claim 1, characterized in that: The outer shapes of the forming groove and the upper concave die (5) and the lower concave die (8) are symmetrical. The upper concave die (5) and the lower concave die (8) are respectively provided with through holes (9) that cooperate with the upper punch (1) and the lower punch (2) for movement. The through holes (9) are connected to the forming cavity (6) and the outside world. The diameter of the through holes (9) is equal to the diameter of the upper punch (1) and the lower punch (2).

6. A forming method of a dual-structure titanium alloy blade disk using a controllable strain isothermal forging die according to any one of claims 1 to 5, characterized in that: The forming method comprises the following steps: S1: Pre-forging a titanium alloy into a blade disk preform (7) by a near-β forging method, wherein the preform wheel disk portion (14) in the blade disk preform (7) has different initial heights, and the preform wheel disk portion (14) and the preform blade portion (10) in the blade disk preform (7) have a basket structure inside; S2: The preformed blade disk (7) pre-forged in S1 is buckled into a forming cavity (6) formed by buckling two forming grooves, an upper punch (1) and a lower punch (2) to perform controllable strain isothermal die forging; S3: The upper punch (1) and the lower punch (2) are driven by an external hydraulic device to squeeze into the forming cavity (6) through the through holes on the upper die (5) and the lower die (8). At a specific temperature, the upper punch (1) and the lower punch (2) isothermally extrude the preform wheel disc portion (14) to a preset thickness at the same extrusion rate. During the die forging process, the basket tissue of the preform wheel disc portion (14) is completely spheroidized to form an equiaxial tissue, and the preform blade portion (10) does not undergo spheroidization and retains the basket tissue. The connection between the preform wheel disc portion (14) and the preform blade portion (10) is gradually spheroidized along the diameter direction to form a gradual transition tissue, and finally a formed blade disc is obtained. The equiaxial tissue of the wheel disc portion (12), the basket tissue of the blade portion (13) and the gradual transition tissue of the connection portion (11) of the formed blade disc present a gradient dual tissue / dual performance distribution.

7. The forming method according to claim 6, characterized in that: The die forging temperature range in the controlled strain isothermal die forging in S3 is 700-880°C, and the radial movement rate range of the upper punch (1) and the lower punch (2) is 0.05-0.4 mm / min.

Images