Preparation method of titanium alloy integral front casing

Abstract

The invention discloses a preparation method of a titanium alloy integral front casing. The preparation method comprises the following steps: S1, preparing before forging; S2, heating a blank and a mold; S3, forging; the upper die and the bottom die are matched to form the inner side of the case, the left lower side die and the right lower side die form the side face of the case, demolding of the left lower side die and the right lower side die from the side face is not affected by a thin kidney-shaped structure on the outer side of the case, and demolding of the upper die and the bottom die is not affected by a thin kidney-shaped structure on the inner side of the case; and finally, a central process auxiliary block is removed through machining to form a hollow casing forge piece, only one set of die and one-heating-number forming are needed, the production efficiency is greatly improved, the reliability of the casing is improved, a die cavity can be designed according to the contour of the casing, the feeding amount and the machining amount are reduced, and the material cost and the machining cost are reduced.

Description

Technical Field

[0001] The present invention relates to the field of metallurgy technology, in particular to the preparation of titanium alloy components, and in particular to a method for preparing a titanium alloy integral front casing. Background Art

[0002] The casing, which covers the rotating components of an aircraft engine, is subject to the erosion of hot air during engine operation. It is typically made of titanium alloy or a high-temperature alloy. Casings manufactured from this integral material offer high precision in machined parts, eliminate the need for mechanical joints, and provide excellent reliability. However, the thin-walled cylindrical structure of the integral casing makes die forging difficult and demolding difficult, especially for the waisted front casing, where the diameter of the center section is smaller than that of the two ends. Using a traditional upper and lower die assembly makes demolding impossible.

[0003] Among existing technologies, Chinese invention publication CN112589021B discloses a method for manufacturing double-flange, high-barreled receiver rings made of IN718 alloy. This method involves punching and expanding the holes, followed by pre-rolling and final rolling to create a thin, waisted receiver ring, which is then processed into a complete receiver. However, this method requires multiple firings and a complex process. Furthermore, machining is required after rolling to create a thin-walled receiver, resulting in significant material waste. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for preparing a titanium alloy integral front casing, which is intended to solve the technical problems in the prior art of inconvenient demoulding of front casing forgings and large processing volume of ring rolling manufacturing machines.

[0005] The method for preparing the titanium alloy integral front casing of the present invention comprises the following steps:

[0006] S1. A pre-forging preparation process: specifically includes the following steps:

[0007] S11, preparing a pancake-shaped blank made of titanium alloy;

[0008] S12. Prepare a mold, comprising an upper mold, a left lower mold, a right lower mold, and a bottom mold, wherein a first molding surface is provided on the right side of the left lower mold, a second molding surface is provided on the left side of the right lower mold, a first boss is provided on the lower side of the upper mold, and a second boss is provided on the upper side of the lower mold, wherein the mold is made of a high-temperature alloy;

[0009] S13. Prepare a hydraulic press, comprising a workbench, a vertical hydraulic device disposed above the workbench, and horizontal hydraulic devices disposed on the left and right sides of the hydraulic press, respectively. The upper mold is mounted at the bottom of the vertical hydraulic device, the bottom mold is mounted on the workbench, and the left and right lower molds are mounted opposite each other on the left and right horizontal hydraulic devices, respectively.

[0010] S2, a process of heating the blank and the mold: heating the blank to a first temperature (T β -60℃)≤the first temperature≤(T β +10℃), where T β The β-transus temperature of the blank is heated to 800-950°C;

[0011] S3. A die forging process: A horizontal hydraulic device is used to apply force to the left and right lower dies in a horizontal direction, so that the right end of the left lower die is aligned with the left end of the right lower die, the left side of the bottom die is aligned with the bottom of the first molding surface, and the right side of the bottom die is aligned with the bottom of the second molding surface. The upper surfaces of the first molding surface, the second molding surface, and the second boss form a mold cavity. Then, a heated blank is placed on the upper edges of the left and right lower dies, and a vertical hydraulic device is used to press the upper die downward until the blank fills the mold cavity, thereby obtaining a casing forging.

[0012] S4, a demoulding process: the upper die is lifted and withdrawn by a vertical hydraulic device, and then the left and right lower side dies are pulled away from the receiver forging by a horizontal hydraulic device, and then the receiver forging is removed;

[0013] S5. A machining process: the process auxiliary block at the center of the casing forging is removed by machining to form a casing forging with a through cavity at the center.

[0014] Specifically, steps S11, S12, and S13 are included in step S1, and step S11 may use a pancake-shaped blank obtained by upsetting a bar or cutting a rolled thick plate;

[0015] Specifically, the cross-sections of the first and second molding surfaces in the mold are both semicircular structures. When the mold is closed, the right end of the left lower mold is affixed to the left end of the right lower mold, and the first molding surface and the second molding surface form a closed circular structure to close the side of the cavity. The left side of the bottom mold is affixed to the bottom of the first molding surface, and the right side of the bottom mold is affixed to the bottom of the second molding surface to close the bottom of the cavity.

[0016] In step S3, a horizontal hydraulic device is used to push the left lower die, right lower die, and bottom die together. The diameter of the billet is 80 to 150 mm larger than the inner diameter of the upper edge of the left and right lower dies after closing. The heated billet is placed on the upper edges of the left and right lower dies. The first boss of the upper die and the second boss of the lower die squeeze the billet to form cavities on the upper and lower sides of the center of the receiver forging. The first molding surface of the left lower die is used to form the left side of the receiver forging, and the second molding surface of the right lower die is used to form the right side of the receiver forging.

[0017] In step S4, since the left lower mold and the right lower mold are moved in the left and right directions to open the mold, the thin waist structure in the middle of the outer side of the receiver will not affect the mold opening, and the thin waist part on the inner side of the receiver is formed between the extrusion positions of the first boss and the second boss, so that it does not affect the demolding of the upper mold.

[0018] In step S5 , the process auxiliary block at the center of the die-forged casing forging may be removed by machining, so that the cavities on the upper and lower sides of the casing forging are connected.

[0019] Furthermore, the cross sections of the first boss and the second boss are both circular, and the side surfaces of the first boss and the second boss are both provided with draft angles.

[0020] Specifically, the interior of the receiver is generally circular, and setting the cross-section of the first boss and the second boss to be circular can reduce the subsequent machining amount. The sides of the first boss and the second boss are both provided with draft angles to facilitate demolding.

[0021] Furthermore, in step S2, glass coating is applied to the outside of the blank before heating the blank.

[0022] Specifically, applying glass protective coating can play a protective role, isolate the air, and prevent metal materials from oxidizing, absorbing hydrogen, and absorbing nitrogen at high temperatures; and when the blank is heated to a high temperature and transferred out of the furnace for forging, the glass protective lubricant can reduce the temperature drop of the blank, play a heat preservation role, and has a lubricating effect, which facilitates subsequent die forging.

[0023] Specifically, the heating temperature of the mold made of high-temperature alloy can reach 800-950° C. in step S2 .

[0024] Compared with the prior art, the present invention has a positive and significant effect. The present invention forms the inner side of the receiver through the cooperation of the upper and lower dies, and the left and right lower dies form the side of the receiver. Demolding the left and right lower dies from the side is not affected by the narrow waist-shaped structure on the outer side of the receiver, and demolding the upper and lower dies is not affected by the narrow waist-shaped structure on the inner side of the receiver. Finally, the center process auxiliary block is removed by machining to form a hollow receiver forging. Only one set of dies and one forming process are required, significantly improving production efficiency and enhancing the reliability of the receiver. The mold cavity can be designed according to the contour of the receiver, reducing the amount of material and machining, and lowering material and machining costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a schematic diagram of the waisted receiver;

[0026] Figure 2 Schematic diagram of a method for preparing a titanium alloy integral front casing of the present invention;

[0027] in, Figure 2The upper die, left lower die, right lower die, bottom die, and receiver forgings are all cross-sectional views;

[0028] Markings in the figure: 1, upper die; 101, first boss; 2, lower left die; 201, first molding surface; 3, lower right die; 301, second molding surface; 4, bottom die; 401, second boss; 5, blank; 6, casing forging; 601, cavity. DETAILED DESCRIPTION

[0029] The present invention will be further described below with reference to the accompanying drawings and examples, but the present invention is not limited thereto.

[0030] Example 1

[0031] like Figure 1-Figure 2 As shown, a method for preparing a Ti6242 titanium alloy integral front casing comprises the following steps:

[0032] S1. A forging preparation process: Prepare a Ti6242 titanium alloy pancake blank 5 with a height h of 85 mm, a diameter d of 794 mm, and a height-to-diameter ratio h / d of 0.107. β The temperature is 990℃ and the mold material is high temperature alloy;

[0033] S2, a process of heating a blank 5 and a mold: first, a glass protective coating is applied to the surface of the blank 5 with a thickness of 0.32 mm, then the blank 5 is heated to 1000°C, with the temperature difference between the core and the surface of the blank 5 being ≤5°C, and the mold is heated to 850°C;

[0034] S3, a die forging process: a horizontal hydraulic device is used to press the left lower die 2 and the right lower die 3 together, so that the right end of the left lower die 2 is in contact with the left end of the right lower die 3, the left side of the bottom die 4 is in contact with the bottom of the first molding surface 201, and the right side of the bottom die 4 is in contact with the bottom of the second molding surface 301. The upper surfaces of the first molding surface 201, the second molding surface 301, and the second boss 401 form a mold cavity. Then, the heated blank 5 is placed on the upper edges of the left lower die 2 and the right lower die 3. The upper die 1 is driven downward by a vertical hydraulic device until the blank 5 fills the mold cavity, thereby obtaining a casing forging 6.

[0035] S4, a demoulding process: the upper die 1 is returned to the top of the receiver forging 6, and then the left lower die 2 and the right lower die 3 are pulled away from the receiver forging 6 by a horizontal hydraulic device, and the receiver forging 6 on the bottom die 4 is clamped by a manipulator;

[0036] S5, a machining process: machining the internal process auxiliary block of the casing forging 6 to form a through cavity 601 inside the casing forging 6.

[0037] Example 2

[0038] like Figure 1-Figure 2 As shown, a method for preparing a Ti6242 titanium alloy integral front casing comprises the following steps:

[0039] S1. A forging preparation process: Prepare a Ti6242 titanium alloy pancake blank 5 with a height h of 88 mm, a diameter d of 780 mm, and a height-to-diameter ratio h / d of 0.113. β The temperature is 990℃ and the mold material is high temperature alloy;

[0040] S2, a process of heating a blank 5 and a mold: first, a glass protective coating is applied to the surface of the blank 5 with a thickness of 0.35 mm, then the blank 5 is heated to 975°C, with the temperature difference between the core and the surface of the blank 5 being ≤5°C, and the mold is heated to 940°C;

[0041] S3, a die forging process: a horizontal hydraulic device is used to press the left lower die 2 and the right lower die 3 together, so that the right end of the left lower die 2 is in contact with the left end of the right lower die 3, the left side of the bottom die 4 is in contact with the bottom of the first molding surface 201, and the right side of the bottom die 4 is in contact with the bottom of the second molding surface 301. The upper surfaces of the first molding surface 201, the second molding surface 301, and the second boss 401 form a mold cavity. Then, the heated blank 5 is placed on the upper edges of the left lower die 2 and the right lower die 3. The upper die 1 is driven downward by a vertical hydraulic device until the blank 5 fills the mold cavity, thereby obtaining a casing forging 6.

[0042] S4, a demoulding process: the upper die 1 is returned to the top of the receiver forging 6, and then the left lower die 2 and the right lower die 3 are pulled away from the receiver forging 6 by a horizontal hydraulic device, and the receiver forging 6 on the bottom die 4 is clamped by a manipulator;

[0043] S5, a machining process: machining the internal process auxiliary block of the casing forging 6 to form a through cavity 601 inside the casing forging 6.

[0044] Example 3

[0045] like Figure 1-Figure 2 As shown, a method for preparing a BT25 titanium alloy integral front casing comprises the following steps:

[0046] S1. A forging preparation process: Prepare a BT25 titanium alloy pancake blank 5 with a height h of 92 mm, a diameter d of 835 mm, and a height-to-diameter ratio h / d of 0.11. β The temperature is 1025℃ and the mold material is high temperature alloy;

[0047] S2, a process of heating a blank 5 and a mold: first, a glass protective coating is applied to the surface of the blank 5 with a thickness of 0.35 mm, then the blank 5 is heated to 1035°C, with the temperature difference between the core and the surface of the blank 5 being ≤5°C, and the mold is heated to 800°C;

[0048] S3, a die forging process: a horizontal hydraulic device is used to press the left lower die 2 and the right lower die 3 together, so that the right end of the left lower die 2 is in contact with the left end of the right lower die 3, the left side of the bottom die 4 is in contact with the bottom of the first molding surface 201, and the right side of the bottom die 4 is in contact with the bottom of the second molding surface 301. The upper surfaces of the first molding surface 201, the second molding surface 301, and the second boss 401 form a mold cavity. Then, the heated blank 5 is placed on the upper edges of the left lower die 2 and the right lower die 3. The upper die 1 is driven downward by a vertical hydraulic device until the blank 5 fills the mold cavity, thereby obtaining a casing forging 6.

[0049] S4, a demoulding process: the upper die 1 is returned to the top of the receiver forging 6, and then the left lower die 2 and the right lower die 3 are pulled away from the receiver forging 6 by a horizontal hydraulic device, and the receiver forging 6 on the bottom die 4 is clamped by a manipulator;

[0050] S5, a machining process: machining the internal process auxiliary block of the casing forging 6 to form a through cavity 601 inside the casing forging 6.

[0051] Example 4

[0052] like Figure 1-Figure 2 As shown, a method for preparing a BT25 titanium alloy integral front casing comprises the following steps:

[0053] S1. A forging preparation process: Prepare a BT25 titanium alloy pancake blank 5 with a height h of 100 mm, a diameter d of 800 mm, and a height-to-diameter ratio h / d of 0.125. β The temperature is 1025℃ and the mold material is high temperature alloy;

[0054] S2, a process of heating a blank 5 and a mold: first, a glass protective coating is applied to the surface of the blank 5 with a thickness of 0.38 mm, then the blank 5 is heated to 965°C, with the temperature difference between the core and the surface of the blank 5 being ≤5°C, and the mold is heated to 950°C;

[0055] S3, a die forging process: a horizontal hydraulic device is used to press the left lower die 2 and the right lower die 3 together, so that the right end of the left lower die 2 is in contact with the left end of the right lower die 3, the left side of the bottom die 4 is in contact with the bottom of the first molding surface 201, and the right side of the bottom die 4 is in contact with the bottom of the second molding surface 301. The upper surfaces of the first molding surface 201, the second molding surface 301, and the second boss 401 form a mold cavity. Then, the heated blank 5 is placed on the upper edges of the left lower die 2 and the right lower die 3. The upper die 1 is driven downward by a vertical hydraulic device until the blank 5 fills the mold cavity, thereby obtaining a casing forging 6.

[0056] S4, a demoulding process: the upper die 1 is returned to the top of the receiver forging 6, and then the left lower die 2 and the right lower die 3 are pulled away from the receiver forging 6 by a horizontal hydraulic device, and the receiver forging 6 on the bottom die 4 is clamped by a manipulator;

[0057] S5, a machining process: machining the internal process auxiliary block of the casing forging 6 to form a through cavity 601 inside the casing forging 6.

[0058] In the above four embodiments, the waist-shaped integral receiver is successfully forged by a one-time die forging method.

[0059] Finally, it should be noted that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art will be able to modify the technical solutions described in the aforementioned embodiments or substitute equivalents for some of the technical features. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A method for preparing a titanium alloy integral front casing, characterized in that: The following steps are involved: S1. A pre-forging preparation process: specifically includes the following steps: S11, preparing a pancake-shaped blank made of titanium alloy; S12. Prepare a mold, comprising an upper mold, a left lower mold, a right lower mold, and a bottom mold, wherein a first molding surface is provided on the right side of the left lower mold, a second molding surface is provided on the left side of the right lower mold, a first boss is provided on the lower side of the upper mold, and a second boss is provided on the upper side of the lower mold, wherein the mold is made of a high-temperature alloy; S13. Prepare a hydraulic press, comprising a workbench, a vertical hydraulic device disposed above the workbench, and horizontal hydraulic devices disposed on the left and right sides of the hydraulic press, respectively. The upper mold is mounted at the bottom of the vertical hydraulic device, the bottom mold is mounted on the workbench, and the left and right lower molds are mounted opposite each other on the left and right horizontal hydraulic devices, respectively. S2, a process of heating the blank and the mold: heating the blank to a first temperature (T β -60℃)≤the first temperature≤(T β +10℃), where T β The β-transus temperature of the blank is heated to 800-950°C; S3. A die forging process: A horizontal hydraulic device is used to apply force to the left and right lower dies in a horizontal direction, so that the right end of the left lower die is aligned with the left end of the right lower die, the left side of the bottom die is aligned with the bottom of the first molding surface, and the right side of the bottom die is aligned with the bottom of the second molding surface. The upper surfaces of the first molding surface, the second molding surface, and the second boss form a mold cavity. Then, a heated blank is placed on the upper edges of the left and right lower dies, and a vertical hydraulic device is used to press the upper die downward until the blank fills the mold cavity, thereby obtaining a casing forging. S4, a demoulding process: the upper die is lifted and withdrawn by a vertical hydraulic device, and then the left and right lower side dies are pulled away from the receiver forging by a horizontal hydraulic device, and then the receiver forging is removed; S5. A machining process: the process auxiliary block at the center of the casing forging is removed by machining to form a casing forging with a through cavity at the center.

2. The method for preparing the titanium alloy integral front casing according to claim 1, characterized in that: The cross sections of the first boss and the second boss are both circular, and the sides of the first boss and the second boss are both provided with draft angles.

3. The method for preparing the titanium alloy integral front casing according to claim 1, characterized in that: In the step S2, glass coating is applied to the outside of the blank before the blank is heated.

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