A method for manufacturing a titanium alloy pre-chamber forging

Abstract

A manufacturing method of a titanium alloy front engine case forging, comprising designing the outer shape structure of a pre-forging blank according to the arc length of the forging; compensating the arc length value by thickening the height size of the corresponding part on the profile surface of the pre-forging blank corresponding to the outer circle of the forging; adding two trapezoidal bosses on the profile surface of the pre-forging blank corresponding to the inner circle of the forging, the positions being the two sides in the length direction; adding a boss in the middle area of the profile surface of the pre-forging blank corresponding to the outer circle of the forging; adding a boss on the profile surface of the pre-forging blank corresponding to the inner circle of the forging, which is used for positioning when the pre-forging blank is put into the die for pre-forging. The present application overcomes the shortcomings of the prior art, can effectively optimize the excess amount distribution of the forging and refine the size of the forging, thereby effectively improving the material utilization rate and effectively improving the product quality. And the lean control of the manufacturing process is strengthened, the material utilization rate is improved. The production process is simplified, and the manufacturing cycle is shortened.

Description

Technical Field

[0001] This invention relates to the field of forging technology, specifically a method for manufacturing a titanium alloy front casing forging. Background Technology

[0002] The titanium alloy front casing is a critical component used in aero engines and is an essential part of aircraft propulsion. Its shape is a ring formed by the merging of two halves, resulting in a complex structure and high requirements for its microstructure and properties. This component is typically manufactured using a process of "forging + heat treatment + machining," with "forging + heat treatment" being the heat treatment step. The quality and precision of the resulting titanium alloy front casing forging have a crucial impact on the final processing and use of the component.

[0003] In existing technology, the forging process for titanium alloy front casing forgings involves treating a half-ring as a single forging. The forging is a complex, irregularly shaped semi-ring. The manufacturing process is completed in six steps: pre-forging, pre-forging billet machining, forming forging, pre-straightening, shaping forging, and heat treatment. The forging processes in this scheme—pre-forging, forming forging, and shaping forging—are semi-open die forging. Compared to the rolled ring manufacturing process, this represents an improvement in product quality stability and dimensional accuracy, but the following technical problems still exist:

[0004] 1. In the "six-step process plan", the forging is made by forming a long arc-shaped forging billet through the "forming forging process", and then bending it through the "pre-straightening process" and the "forming forging process". The final shape of the forging is not a standard semi-circular ring. The single-side allowance of some areas to the part is about 15mm, while that of some areas is about 8mm. The allowance is large and unevenly distributed, and the material utilization rate is about 20%.

[0005] 2. The "forming forging process" will generate a lot of flash, and the metal will be removed as required in the "pre-forging billet machining" process, resulting in a certain amount of material loss. The forging yield is 70%-80%.

[0006] 3. The “pre-forging process”, “forming forging process” and “shaping forging process” in the “six-step process plan” involve heating, cooling and loading / unloading of three sets of special molds, and three forging processes must be carried out, which results in a long manufacturing cycle. Summary of the Invention

[0007] To address the shortcomings of existing technologies, this invention provides a method for manufacturing a titanium alloy front casing forging. This method overcomes the deficiencies of existing technologies, effectively optimizing the forging allowance distribution and refining the forging dimensions, thereby significantly improving material utilization and product quality. Furthermore, it strengthens lean control of the manufacturing process, further enhancing material utilization, simplifying production procedures, and shortening the manufacturing cycle.

[0008] To achieve the above objectives, the present invention provides the following technical solution:

[0009] A method for manufacturing a titanium alloy front casing forging includes a process for designing a pre-forging billet, a process for manufacturing the pre-forging billet, and a process for forging the titanium alloy front casing forging, wherein...

[0010] The process of designing the pre-forged billet includes the following steps:

[0011] S1: Design the shape structure of the pre-forged billet according to the arc length of the forging; First, calculate the average value of the inner and outer arc lengths of each part of the forging according to each surface of the forging. Then, take the calculated average value of the inner and outer arc lengths as the length dimension of the pre-forged billet. Combine adjacent parts with a difference of 5mm-15mm into a cuboid block with the longest arc length as the long side. Design the parts that cannot be combined into trapezoidal blocks. Finally, adjust the length dimension of the pre-forged billet to make it the size after reducing the length dimension of the forging by 2mm-10mm.

[0012] S2: The arc length is compensated by thickening the corresponding part of the profile surface of the pre-forged billet corresponding to the outer circle of the forging. The ratio of the compensation amount to the thickening size is 1:1.

[0013] S3: Add two trapezoidal bosses to the inner circle of the forging corresponding to the pre-forging billet, located on both sides of the length direction;

[0014] S4: Add a boss in the middle area of ​​the profile of the pre-forged billet corresponding to the outer circle of the forging. Depending on the location of the boss, design the length of the boss to be 1 / 3-1 / 4 of the length of the pre-forged billet profile at the corresponding position; the height dimension is 10mm-20mm.

[0015] S5: Add a boss with a height of 5mm-10mm to the profile surface of the inner circle of the forging corresponding to the pre-forging billet. This is used to position the pre-forging billet when it is placed into the mold used for pre-forging.

[0016] The process of manufacturing the pre-forged billet includes the following steps:

[0017] P1: Heat the titanium alloy bar to the two-phase region and hold it at the same temperature, while simultaneously heating and holding the mold used for pre-forging at the same temperature.

[0018] P2: Place the titanium alloy bar that has been heated and kept warm in step P1 into the cavity of the mold that has been heated and kept warm, and close the mold.

[0019] P3: Operate the press equipment to pre-forge and shape the titanium alloy bar in the mold;

[0020] P4: Open the mold and remove the pre-forged billet.

[0021] In the process of forging the titanium alloy front casing, the pre-forged billet obtained in step P4 is finished, cleaned, and inspected; then it is heated to the two-phase region of the material and held at that temperature, while the mold used for the forming forging process is heated to the same temperature and held at that temperature; then the trapezoidal plate-shaped pre-forged billet that has been heated and held at that temperature is placed into the cavity of the mold used for the forming forging process and the mold is closed; then the press equipment is operated to form the pre-forged billet in the mold and forge it into shape; then the mold used for the forming forging process is opened, and the finished titanium alloy front casing forging is taken out; then the titanium alloy front casing forging is heat-treated and finished and cleaned; finally, sampling is completed and inspected again.

[0022] Preferably, in step S3, the length of the trapezoidal boss is 1.5-2.5 times the length of the mounting edge of the forging, the width is equal to the total width of the pre-forging billet, and the height is equal to the thickness of the mounting edge of the forging.

[0023] Preferably, the boss described in step S4 is provided with a draft angle.

[0024] Preferably, after completing step P4, the pre-forged billet is finished, cleaned, and inspected.

[0025] Preferably, in the process of forging the titanium alloy front casing, the die used in the forming forging process includes an upper die and a lower die. The upper die has an arc-shaped mating block, and the lower die has a cross-shaped mating block. When the upper die begins to enter the cavity of the lower die, the middle part of the arc-shaped mating block engages with the vertical block of the cross-shaped mating block for limiting. As the forging process proceeds, the depth of the upper die entering the cavity of the lower die continuously increases, and the two sides of the arc-shaped mating block engage with the lateral blocks of the cross-shaped mating block for limiting.

[0026] Preferably, during the forging process of the titanium alloy front casing, the forming process of the titanium alloy front casing is predicted by finite element numerical simulation, and the design of the pre-forged billet and the mold structure are optimized and verified by the prediction.

[0027] This invention provides a method for manufacturing a titanium alloy front casing forging. It offers the following advantages: it effectively optimizes the forging allowance distribution and refines the forging dimensions, thereby significantly improving material utilization and product quality. Furthermore, it strengthens lean control of the manufacturing process, further enhancing material utilization. It also simplifies production procedures and shortens the manufacturing cycle. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in this invention or the prior art, the accompanying drawings used in the description of the prior art will be briefly introduced below:

[0029] Figure 1 A schematic diagram of the front casing forging in this invention;

[0030] Figure 2 A top view of the profile of the pre-forged billet relative to the outer circle of the forging in this invention;

[0031] Figure 3 A bottom view of the profile of the pre-forged billet relative to the inner circle of the forging in this invention;

[0032] Figure 4 A schematic diagram of the upper mold in the forming forging process of this invention;

[0033] Figure 5 A schematic diagram of the structure of the lower die in the forming and forging process of this invention.

[0034] Explanation of the labels in the diagram:

[0035] 1. Upper mold; 2. Lower mold; 3. Arc-shaped mating block; 4. Cross-shaped mating block; 11. Outer arc surface of the front casing forging; 12. Inner arc surface of the front casing forging; 13. Mounting edge of the front casing forging. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Example 1

[0037] like Figures 1 to 5 As shown, this invention is based on the principle of superplasticity of titanium alloys, that is, the material can undergo large ductility and deformation under high temperature and high pressure, thereby realizing the metal flow forming of complex structures. It includes a process of designing a pre-forged billet, a process of manufacturing the pre-forged billet, and a process of forging a titanium alloy front casing forging.

[0038] First, based on the arc length of the semi-circular rings at different positions of the front casing forging, and considering the metal flow pattern during forming, a trapezoidal plate-shaped pre-forging blank based on the arc length of the semi-circular rings is designed according to the surface characteristics. Specifically, this includes:

[0039] S1: Pre-forging billet contour design: The pre-forging billet's external structure is designed based on the arc length of the forging; the width of the pre-forging billet is 2mm-10mm smaller than the width of the forging; the length of the pre-forging billet is a trapezoidal structure; specifically, firstly, the average inner and outer arc lengths of each part of the forging are calculated according to different surfaces of the forging, then the calculated average inner and outer arc lengths are used as the length of the pre-forging billet. Adjacent parts with a difference of 5mm-15mm are merged and designed into a cuboid block with the longest arc length as the long side. Parts that cannot be merged are designed as trapezoidal blocks. Finally, the length of the pre-forging billet is adjusted to be the size after the length of the forging is reduced by 2mm-10mm; the height of the pre-forging billet is calculated based on the weight of the forging, the material density, and the width and length dimensions; that is: the volume of the forging can be obtained from the weight of the forging and the density of the material, and then the volume formula can be used to calculate the height of the pre-forging billet from the forging and the width and length dimensions.

[0040] S2: The “merging arc length” and “adjusting length dimension” in the above pre-forged billet contour design will cause the length dimension of some positions in the pre-forged billet to be smaller than the arc length of the corresponding position in the forging;

[0041] Therefore, the arc length is compensated by thickening the corresponding part of the profile surface of the pre-forged billet on the outer circle of the forging. The ratio of the compensation amount to the thickening dimension is 1:1. For example, if the arc length of a certain part of the forging is 1000mm, and the length of the pre-forged billet at the corresponding part is 980mm, then the height must be thickened by 20mm.

[0042] S3: Add two trapezoidal bosses to the profile of the inner circle of the forging corresponding to the pre-forging billet, located on both sides along the length direction; the length of the trapezoidal bosses is 1.5-2.5 times the length of the mounting edge of the forging; the width is equal to the total width of the pre-forging billet; and the height is equal to the thickness of the mounting edge of the forging. The mounting edge of the forging consists of two trapezoidal blocks on both sides of the forging, such as... Figure 1 As shown.

[0043] S4: Design optimization based on metal flow: During the process of forming a semi-circular ring-shaped forging from a trapezoidal plate-shaped pre-forging billet, the metal flows from the middle to both sides. Therefore, the amount of metal in the middle of the pre-forging billet should be greater than that on both sides.

[0044] Therefore, by adding a boss in the middle area of ​​the profile of the pre-forged billet corresponding to the outer circle of the forging, the length of the boss is designed to be 1 / 3-1 / 4 of the length of the pre-forged billet profile at the corresponding position, depending on the location of the boss; the height dimension is 10mm-20mm.

[0045] In addition, to allow the metal to flow more efficiently and for forgings to form smoothly, draft angles can be increased for the bosses at various locations, preferably 30°-60°.

[0046] S5: Bar blank positioning design: The trapezoidal plate-shaped pre-forged billet used for the front casing forging is pressed into the cavity of the mold used for pre-forging after the bar material is cut according to the process requirements.

[0047] Therefore, in order to ensure the smooth forming of the pre-forged billet, a boss is added to the inner circle of the forging corresponding to the bar blank according to the blank size. The boss is a groove relative to the cavity of the mold used for pre-forging, with a height of 5mm-10mm, which is used to position the pre-forged billet when it is placed into the mold used for pre-forging.

[0048] By adopting the pre-forged billet based on the semi-circular arc length, the forging allowance distribution can be effectively optimized and the forging size can be refined. As a result, the allowance in each area of ​​the forging is about 5mm on each side, thereby increasing the material utilization rate from 20% to about 30% and effectively improving product quality. Example 2

[0049] A method for manufacturing a titanium alloy front casing forging further includes the following steps:

[0050] Step P1: Heat the titanium alloy bar to the two-phase region and hold it at the same temperature, while simultaneously heating and holding the mold used for pre-forging at the same temperature.

[0051] Step P2: Place the titanium alloy bar that has been heated and kept warm in step S1 into the cavity of the mold that has been heated and kept warm, and close the mold.

[0052] Step P3: Operate the press equipment to pre-forge and shape the titanium alloy bar in the mold;

[0053] Step P4: Open the mold and remove the completed trapezoidal plate-shaped pre-forged billet;

[0054] Step P5: Finish, clean, and inspect the trapezoidal plate-shaped semi-circular annular arc length pre-forged billet obtained in step P4;

[0055] Step P6: Heat the trapezoidal plate-shaped pre-forged billet to the two-phase region of the material and hold it at the same temperature. At the same time, heat the mold used for the forming forging process at the same temperature and hold it at the same temperature.

[0056] Step P7: Place the pre-forged trapezoidal plate, which has been heated and kept warm, into the cavity of the mold used in the forming forging process, which has been heated and kept warm, and close the mold.

[0057] Step P8: Operate the press equipment to form and shape the pre-forged billet in the mold;

[0058] Step P9: Open the mold used in the forming forging process and take out the finished titanium alloy front casing forging;

[0059] Step S10: Heat treat and finish the titanium alloy front casing forging;

[0060] Step S11: Complete sampling and test again.

[0061] In step P6, the mold used in the forming forging process includes an upper mold 1 and a lower mold 2. The upper mold 1 is provided with an arc-shaped mating block 3, and the lower mold 2 is provided with a cross-shaped mating block 4. When the upper mold 1 begins to enter the cavity of the lower mold 2, the middle part of the arc-shaped mating block 3 engages with the vertical block of the cross-shaped mating block 4 for limiting. As the forging process proceeds, the depth of the upper mold 1 entering the cavity of the lower mold 2 continuously increases, and the two sides of the arc-shaped mating block 3 engage with the lateral block of the cross-shaped mating block 4 for limiting.

[0062] Additionally, step S12 is included: based on the stress-strain curve, thermal conductivity, and thermal expansion coefficient of the titanium alloy material, the material temperature in the heat transfer model is set to 30℃-50℃ below the phase transformation point of the titanium alloy material, ensuring sufficient contact heat exchange, with a friction coefficient of 0.3-0.7 and a minimum element mesh length of no more than 1mm. The forming process of the titanium alloy front casing forging is predicted using finite element numerical simulation, and the design of the pre-forging billet and the die structure are optimized and verified based on the prediction.

[0063] The manufacturing method described above for titanium alloy front casing forgings, compared to the traditional "six-step process," eliminates the high-wear "pre-forging billet machining" and "forming forging" steps, increasing the forging yield from 70%-80% to over 95%. Furthermore, from the perspectives of mold loading / unloading and process execution, the production cycle is shortened from two months per batch to one month, effectively increasing product delivery capability.

[0064] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for manufacturing a titanium alloy front casing forging, characterized in that: This includes a process for designing a pre-forged billet, a process for manufacturing the pre-forged billet, and a process for forging a titanium alloy front casing forging, wherein... The process of designing the pre-forged billet includes the following steps: S1: Design the shape structure of the pre-forged billet according to the arc length of the forging; First, calculate the average value of the inner and outer arc lengths of each part of the forging according to each surface of the forging. Then, take the calculated average value of the inner and outer arc lengths as the length dimension of the pre-forged billet. Combine adjacent parts with a difference of 5mm-15mm into a cuboid block with the longest arc length as the long side. Design the parts that cannot be combined into trapezoidal blocks. Finally, adjust the length dimension of the pre-forged billet to make it the size after reducing the length dimension of the forging by 2mm-10mm. S2: The arc length is compensated by thickening the corresponding part of the profile surface of the pre-forged billet corresponding to the outer circle of the forging. The ratio of the compensation amount to the thickening size is 1:

1. S3: Add two trapezoidal bosses to the profile of the inner circle of the forging corresponding to the pre-forging billet, located on both sides of the length direction; S4: Add a boss in the middle area of ​​the profile of the pre-forged billet corresponding to the outer circle of the forging. Depending on the location of the boss, design the length of the boss to be 1 / 3-1 / 4 of the length of the pre-forged billet profile at the corresponding position; the height dimension is 10mm-20mm. S5: Add a boss with a height of 5mm-10mm to the profile surface of the inner circle of the forging corresponding to the pre-forging billet, which is used for positioning when the pre-forging billet is placed into the mold used for pre-forging; The process of manufacturing the pre-forged billet includes the following steps: P1: Heat the titanium alloy bar to the two-phase region and hold it at the same temperature, while simultaneously heating and holding the mold used for pre-forging at the same temperature. P2: Place the titanium alloy bar that has been heated and kept warm in step P1 into the cavity of the mold that has been heated and kept warm, and close the mold. Step P3: Operate the press equipment to pre-forge and shape the titanium alloy bar in the mold; Step P4: Open the mold and remove the pre-forged billet; In the process of forging the titanium alloy front casing, the pre-forged billet obtained in step P4 is finished, cleaned, and inspected; then it is heated to the two-phase region of the material and held at that temperature, while the mold used for the forming forging process is heated to the same temperature and held at that temperature; then the trapezoidal plate-shaped pre-forged billet that has been heated and held at that temperature is placed into the cavity of the mold used for the forming forging process and the mold is closed; then the press equipment is operated to form the pre-forged billet in the mold and forge it into shape; then the mold used for the forming forging process is opened, and the finished titanium alloy front casing forging is taken out; then the titanium alloy front casing forging is heat-treated and finished and cleaned; finally, sampling is completed and inspected again.

2. The method for manufacturing the titanium alloy front casing forging according to claim 1, characterized in that: In step S3, the length of the trapezoidal boss is 1.5-2.5 times the length of the mounting edge of the forging, the width is equal to the total width of the pre-forged billet, and the height is equal to the thickness of the mounting edge of the forging.

3. The method for manufacturing the titanium alloy front casing forging according to claim 1, characterized in that: The boss described in step S4 is provided with a draft angle.

4. The method for manufacturing the titanium alloy front casing forging according to claim 1, characterized in that: After completing step P4, the pre-forged billet is finished, cleaned, and inspected.

5. The method for manufacturing the titanium alloy front casing forging according to claim 1, characterized in that: In the process of forging the titanium alloy front casing, the mold used in the forming forging process includes an upper mold (1) and a lower mold (2). The upper mold (1) is provided with an arc-shaped mating block (3), and the lower mold (2) is provided with a cross-shaped mating block (4). When the upper mold (1) begins to enter the cavity of the lower mold (2), the middle part of the arc-shaped mating block (3) is mated with the vertical block of the cross-shaped mating block (4) for limiting. As the forging process proceeds, the depth of the upper mold (1) entering the cavity of the lower mold (2) continuously increases, and the two sides of the arc-shaped mating block (3) are mated with the horizontal block of the cross-shaped mating block (4) for limiting.

6. The method for manufacturing the titanium alloy front casing forging according to claim 1, characterized in that: In the process of forging the titanium alloy front casing, the forming process of the titanium alloy front casing is predicted by finite element numerical simulation. The prediction is used to optimize and verify the design of the pre-forged billet and the mold structure.

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