TA15 titanium alloy frame beam forging method and TA15 titanium alloy frame beam

Abstract

The invention provides a TA15 titanium alloy frame beam forging method and a TA15 titanium alloy frame beam, and relates to the field of aircraft part forging. The method comprises the steps that a TA15 titanium alloy bar is obtained; the TA15 titanium alloy bar is subjected to free forging and pre-forming to form an intermediate blank; the intermediate billet is forged in the alpha + beta two-phase region temperature interval according to a preset strain rate interval, and a TA15 titanium alloy frame beam forged piece is obtained; and the strain rate interval is 0.01 s <-1 > to 0.10 s <-1 >. The method is suitable for the forging process of TA15 titanium alloy frame beams and is used for guaranteeing the structure and performance of TA15 titanium alloy forgings.

Description

Technical Field

[0001] The present application relates to the field of forging, specifically to the field of aircraft parts forging, and in particular to a TA15 titanium alloy frame beam forging method and a TA15 titanium alloy frame beam. Background Art

[0002] TA15 titanium alloy has good corrosion resistance, excellent high temperature strength, good thermal stability and plasticity, and is widely used in aircraft load-bearing structures.

[0003] Aircraft load-bearing structures usually have the characteristics of high ribs, thin belly, complex shape, and large projection area, which places high demands on the performance of forging structure.

[0004] Therefore, how to ensure the organization and performance of TA15 titanium alloy forgings has become our need. Summary of the invention

[0005] The present application provides a TA15 titanium alloy frame beam forging method, which is used to ensure the structure and performance of TA15 titanium alloy forgings.

[0006] In the first aspect, the present application provides a TA15 titanium alloy frame beam forging method, the method comprising: obtaining a TA15 titanium alloy bar; preforming the TA15 titanium alloy bar into an intermediate billet by free forging; forging the intermediate billet in the α+β two-phase temperature range according to a preset strain rate range to obtain a TA15 titanium alloy frame beam forging; the strain rate range is 0.01s -1 To 0.10s -1 .

[0007] Optionally, the temperature interval of the α+β two-phase region is 875°C to 980°C.

[0008] Optionally, the method further includes: annealing the TA15 titanium alloy frame beam forging.

[0009] Optionally, after annealing the TA15 titanium alloy frame beam forging, the method further comprises: performing an additional stress relief annealing on the TA15 titanium alloy frame beam forging.

[0010] Optionally, the TA15 titanium alloy rod is obtained by melting in a vacuum consumable arc furnace.

[0011] Optionally, the TA15 titanium alloy rod is obtained by melting three times in a vacuum consumable arc furnace.

[0012] Optionally, the TA15 titanium alloy rod includes 2.30% zirconium, 2.29% vanadium, less than 0.010% iron, 0.020% carbon, 0.033% silicon, 1.74% molybdenum, 6.81% aluminum, 0.0017% hydrogen, 0.12% oxygen, and 0.0034% nitrogen.

[0013] Optionally, the method further comprises: performing room temperature tensile, room temperature impact, hardness, and fracture toughness tests on the TA15 titanium alloy frame beam forging.

[0014] Optionally, the method further includes: setting the heating temperature of the intermediate billet to 950° C., performing numerical simulation of equivalent strain distribution of the forging process according to a preset strain rate range, and analyzing the actual strain distribution rate of the TA15 titanium alloy frame beam forging.

[0015] The TA15 titanium alloy frame beam forging method provided in the present application can obtain a TA15 titanium alloy bar, preform the TA15 titanium alloy bar into an intermediate billet by free forging, and heat the intermediate billet in the α+β two-phase temperature range according to 0.01s -1 To 0.10s -1 Forging was performed to obtain TA15 titanium alloy frame beam forgings. According to the room temperature tensile, room temperature impact, hardness, fracture toughness test, and numerical simulation results, it can be seen that the forging strain rate value is within a reasonable range, the forging scheme design is reasonable and feasible, the physical and chemical tests all meet the index requirements, and the forging plasticity margin is high.

[0016] In a second aspect, the present application provides a TA15 titanium alloy frame beam, which is manufactured using the forging method described in the first aspect.

[0017] The beneficial effects of the second aspect above can be referred to those described in the first aspect above and will not be elaborated on again. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 A schematic diagram of the design of a TA15 titanium alloy frame beam forging provided in an embodiment of the present application; Figure 2 A schematic diagram of the actual shape of the TA15 titanium alloy frame beam forging provided in an embodiment of the present application; Figure 3This is a cross-sectional view of the equivalent strain distribution after die forging provided in an embodiment of the present application; Figure 4 A cross-sectional view of the equivalent strain rate distribution after die forging provided in an embodiment of the present application; Figure 5 A physical picture of the TA15 titanium alloy frame beam forging provided in the embodiment of the present application; Figure 6 A low-magnification microstructure diagram of a forging provided in an embodiment of the present application; Figure 7 A high-magnification (×500) organizational diagram of a forging provided in an embodiment of the present application; Figure 8 A schematic flow chart of the TA15 titanium alloy frame beam forging method provided in an embodiment of the present application. DETAILED DESCRIPTION

[0020] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0021] It should be noted that, in the embodiments of the present application, words such as "exemplarily" or "for example" are used to indicate examples, illustrations or descriptions. Any embodiment or design described as "exemplarily" or "for example" in the embodiments of the present application should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of words such as "exemplarily" or "for example" is intended to present related concepts in a specific way.

[0022] In order to facilitate the clear description of the technical solutions of the embodiments of the present application, in the embodiments of the present application, the words "first", "second", etc. are used to distinguish the same items or similar items with basically the same functions and effects. Those skilled in the art can understand that the words "first", "second", etc. are not limiting the quantity and execution order.

[0023] The nominal composition of TA15 titanium alloy is Ti-6.5Al-2Zr-1Mo-1V, which is a near-α-type medium-strength titanium alloy with high Al equivalent. Its strengthening mechanism is mainly through the solid solution strengthening of α-stabilizing element Al, and the addition of neutral element Zr and β-stabilizing elements Mo and V can improve the process performance.

[0024] Because TA15 titanium alloy has good corrosion resistance, excellent high temperature strength, good thermal stability and plasticity, it is widely used in aircraft load-bearing structures.

[0025] However, aircraft load-bearing structures usually have the characteristics of high ribs, thin belly, complex shape, and large projection area, which places high demands on the performance of forging structure.

[0026] Therefore, how to ensure the organization and performance of TA15 titanium alloy forgings has become our need.

[0027] (1) Forging research and development.

[0028] (1.1) Process analysis.

[0029] A TA15 titanium alloy frame beam forging is taken as an example for analysis.

[0030] For example, Figure 1 This is a schematic diagram of the design of the TA15 titanium alloy frame beam forging provided in the embodiment of the present application. Figure 1 As shown, the TA15 titanium alloy frame beam forging includes a rectangular web at the bottom and a rib wall protruding from the rectangular web. The main body of the rib wall can be regarded as a cuboid standing on the rectangular web. The width of the cuboid is less than or equal to the width of the rectangular web, and one side of the wide side of the cuboid is aligned with the wide side of the rectangular web. The rib wall is smoothly connected to the upper surface of the rectangular web in the length direction of the rectangular web, forming a continuous curved transition. A groove is provided on the top of the rib wall, and the side and bottom surfaces of the groove are smoothly connected to form a continuous curved transition. The side wall of the rib wall includes a plurality of trapezoidal reinforcing ribs spaced apart along the length direction of the rectangular web.

[0031] In some embodiments, the bottom of the rectangular web is also raised with a raised structure.

[0032] For example, the bottom of the rectangular web also has two semi-cylindrical protrusions protruding therefrom, and the length direction of the rectangular side of each semi-cylindrical protrusion is the same as the length direction of the rectangular web. The two semi-cylindrical protrusions are respectively located at a preset length inside the long side of the rectangular web. Each semi-cylindrical protrusion may also include a plurality of annular protrusions spaced apart along the length direction of the rectangular web.

[0033] The length of the rectangular web is about 1.73 meters (m), the theoretical weight is 354 kilograms (kg), and the parting projection area is 0.564 square meters (m 2 ), which is a long strip forging that is difficult to form with high ribs, thin walls, multiple bosses and large cross-sectional area variations.

[0034] The intermediate billet determines the metal flow and filling effect of the final forging. Considering that the metal flow resistance is large at the thin-walled high ribs of the forging, filling is difficult, and the web is thin, which is easy to rise in temperature during forming and cause uneven structure. Free forging can be used to pre-form the intermediate billet with a size close to the forging. Effectively realize the reasonable distribution of the initial volume at different positions of the forging, ensure sufficient metal flow during subsequent die forging, and obtain good filling effect, uniform deformation and structure that meets technical requirements.

[0035] (1.2) Numerical simulation.

[0036] The whole process of die forging of TA15 titanium alloy frame beam forging was numerically simulated by simulation software. The simulated forging was well filled.

[0037] For example, Figure 2 This is a schematic diagram of the actual shape of the TA15 titanium alloy frame beam forging provided in the embodiment of the present application. Figure 2 As shown, the actual shape of the forging is Figure 1 Compared with the design of the original, it has more rough edges.

[0038] The selected forging is forged within the α+β two-phase temperature range and the preset strain rate range.

[0039] Optionally, the temperature range of the α+β two-phase region is 875°C to 980°C. The preset strain rate range is 0.01s -1 To 0.10s -1 .

[0040] The billet heating temperature was set to 950°C, and the forging was numerically simulated.

[0041] For example, Figure 3 This is a cross-sectional view of the equivalent strain distribution after die forging provided in the embodiment of the present application. Figure 3 As shown, the deformation of the body is about 30% to 50%.

[0042] For example, Figure 4 This is a cross-sectional diagram of the equivalent strain rate distribution after die forging provided in the embodiment of the present application. Figure 4 As shown, the strain rate of the forging is mainly 0.02 / s -1 ~0.06 / s -1 The large local deformation and high strain rate at the burrs and process bosses are due to the shape characteristics of high-ribbed and thin-walled frame beams and the process characteristics of die forging, and have no effect on the forging body.

[0043] By analyzing the results of forging numerical simulation, the forging strain rate is within a reasonable range, indicating that the forging design is reasonable and feasible.

[0044] The technical requirements require that the microstructure of the forging after annealing should be a uniform structure processed in the α+β two-phase region. The heat treatment system for forgings is selected as annealing. In order to ensure the use requirements of subsequent parts processing and prevent stress release during part processing, the forgings are subjected to an additional stress relief annealing after annealing.

[0045] (2) Forging production.

[0046] (2.1) Chemical composition.

[0047] The raw materials used in the test are TA15 titanium alloy bars with a diameter of 350 mm. The smelting method is vacuum consumable arc furnace smelting, and the smelting times are three times. The chemical composition is shown in Table 1 below: Table 1 As shown in Table 1, the TA15 titanium alloy rod includes 2.30% zirconium, 2.29% vanadium, less than 0.010% iron, 0.020% carbon, 0.033% silicon, 1.74% molybdenum, 6.81% aluminum, 0.0017% hydrogen, 0.12% oxygen, and 0.0034% nitrogen.

[0048] (2.2) Process route.

[0049] The main production process of forgings is: cutting, billet making, die forging, heat treatment, and physical and chemical testing.

[0050] For example, Figure 5 This is a real picture of the TA15 titanium alloy frame beam forging provided in the embodiment of this application. Please refer to Figure 5 , Figure 5 A physical image of a TA15 titanium alloy frame beam is shown in FIG.

[0051] (3) Physical and chemical results After production is completed, the forgings are dissected for physical and chemical tests, room temperature tensile, room temperature impact, hardness, and fracture toughness tests. The specific results can be shown in Tables 2 and 2 below.

[0052] Table 2: Room temperature tensile and room temperature impact test results As shown in Table 2, the tensile strength (Rm, in megapascals (MPa)), stress value at 0.2% non-proportional elongation (Rp0.2, in MPa), elongation after fracture (A, in %), reduction of area (Z, in %), and impact toughness (ak, in joules per square centimeter (J / cm 2 )) all meet the index requirements, and the plasticity margin of forgings is relatively high.

[0053] Table 3: Fracture toughness and hardness test results As shown in Table 3, the hardness and fracture toughness of many samples meet the index requirements.

[0054] For example, Figure 6 This is a low-magnification structure diagram of the forging provided in the embodiment of the present application. Figure 6 As shown, there are no defects and clear crystals in the low-magnification structure, the grain thickness is no more than 100mm, and the streamline direction follows the shape.

[0055] For example, Figure 7 This is a high-magnification (×500) organizational diagram of the forging provided in the embodiment of the present application. Figure 7 As shown, the microstructure is a uniform structure composed of α+β phases, all β grain boundaries are fully broken, there is no continuous and straight grain boundary α phase, the primary α phase content is 25%, and the length of the elongated α phase does not exceed 0.25 mm.

[0056] Based on the understanding of the above embodiments, the embodiments of the present application also provide a TA15 titanium alloy frame beam forging method. Figure 8 This is a schematic diagram of the process flow of the TA15 titanium alloy frame beam forging method provided in the embodiment of the present application. Figure 8 As shown, the method includes the following steps: S101. Obtain TA15 titanium alloy rod.

[0057] Optionally, as described above, the TA15 titanium alloy rod may include 2.30% zirconium, 2.29% vanadium, less than 0.010% iron, 0.020% carbon, 0.033% silicon, 1.74% molybdenum, 6.81% aluminum, 0.0017% hydrogen, 0.12% oxygen, and 0.0034% nitrogen.

[0058] Alternatively, as described above, the TA15 titanium alloy rod can be obtained by melting in a vacuum consumable arc furnace.

[0059] For example, TA15 titanium alloy rods can be obtained by melting three times in a vacuum consumable arc furnace.

[0060] S102, preforming the TA15 titanium alloy bar into an intermediate billet by free forging.

[0061] S103, forging the intermediate billet in the α+β two-phase temperature range according to a preset strain rate range to obtain a TA15 titanium alloy frame beam forging.

[0062] Among them, the strain rate interval is 0.01s -1 To 0.10s -1 .

[0063] In some possible embodiments, after the TA15 titanium alloy frame beam forging is obtained by forging, the TA15 titanium alloy frame beam forging may be annealed.

[0064] Optionally, after annealing, the TA15 titanium alloy frame beam forging may be subjected to an additional stress relief annealing.

[0065] In some possible embodiments, the method may further include: performing room temperature tensile, room temperature impact, hardness, and fracture toughness tests on the TA15 titanium alloy frame beam forging. For details, please refer to Table 2 and Table 3 of the above (3) Physical and Chemical Results, which will not be repeated here.

[0066] In some other possible embodiments, the method may further include: setting the heating temperature of the intermediate billet to 950°C, performing equivalent strain distribution numerical simulation on the forging process according to a preset strain rate range, and analyzing the actual strain distribution rate of the TA15 titanium alloy frame beam forging. For details, please refer to the numerical simulation process in (1.2) above. Figure 3 and Figure 4 It has been described in detail and will not be repeated here.

[0067] The TA15 titanium alloy frame beam forging method provided in the embodiment of the present application can obtain a TA15 titanium alloy bar, preform the TA15 titanium alloy bar into an intermediate billet by free forging, and heat the intermediate billet in the α+β two-phase temperature range according to 0.01s -1 To 0.10s -1 Forging is performed to obtain TA15 titanium alloy frame beam forgings. According to the above room temperature tensile, room temperature impact, hardness, fracture toughness test, and numerical simulation results, it can be seen that the forging strain rate value is within a reasonable range, the forging scheme design is reasonable and feasible, the physical and chemical tests all meet the index requirements, and the forging plasticity margin is high.

[0068] The above is an introduction to the technical solution of the present application from the perspective of the method. In an exemplary embodiment, the present application also provides a TA15 titanium alloy frame beam, which is forged by the TA15 titanium alloy frame beam forging method provided by the above method embodiment.

[0069] As a key part of an aircraft, frame beam forgings are subjected to complex and severe fatigue stress. In order to ensure the safety and reliability of frame beam forgings during aircraft operation, the present application embodiment performs a numerical simulation analysis on the forming process of a TA15 frame beam forging and conducts production verification, and draws the following conclusions: 1. Numerical simulation analysis can shorten the product development cycle, reduce the mold trial manufacturing process, and improve the quality of die forging. It is a powerful design, analysis and optimization tool for die forging process.

[0070] 2. The two-phase zone forging + annealing and stress relief annealing process can be used to obtain high-plasticity TA15 titanium alloy forgings that meet the index requirements.

[0071] Although the present application has been described in conjunction with specific features and embodiments thereof, it is obvious that various modifications and combinations may be made thereto without departing from the spirit and scope of the present application. Accordingly, this specification and the drawings are merely exemplary illustrations of the present application as defined by the appended claims, and are deemed to have covered any and all modifications, variations, combinations or equivalents within the scope of the present application. Obviously, those skilled in the art may make various modifications and variations to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.

[0072] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A TA15 titanium alloy frame beam forging method, characterized in that: The method comprises: Obtain TA15 titanium alloy bars; Free forging and preforming the TA15 titanium alloy bar into an intermediate billet; The intermediate billet is forged in the α+β two-phase temperature range according to a preset strain rate range to obtain a TA15 titanium alloy frame beam forging; the strain rate range is 0.01s -1 To 0.10s -1 .

2. The method according to claim 1, characterized in that The temperature range of the α+β two-phase region is 875°C to 980°C.

3. The method according to claim 1, characterized in that The method further comprises: The TA15 titanium alloy frame beam forging is annealed.

4. The method according to claim 3, characterized in that After annealing the TA15 titanium alloy frame beam forging, the method further comprises: The TA15 titanium alloy frame beam forging is subjected to an additional stress relief annealing.

5. The method according to any one of claims 1 to 4, characterized in that: The TA15 titanium alloy rod is obtained by melting in a vacuum consumable arc furnace.

6. The method according to claim 5, characterized in that The TA15 titanium alloy rod is obtained by melting three times in a vacuum consumable arc furnace.

7. The method according to claim 1, characterized in that The TA15 titanium alloy rod includes 2.30% zirconium, 2.29% vanadium, less than 0.010% iron, 0.020% carbon, 0.033% silicon, 1.74% molybdenum, 6.81% aluminum, 0.0017% hydrogen, 0.12% oxygen, and 0.0034% nitrogen.

8. The method according to claim 1, characterized in that The method further comprises: The TA15 titanium alloy frame beam forgings were subjected to room temperature tensile, room temperature impact, hardness, and fracture toughness tests.

9. The method according to claim 1, characterized in that: The method further comprises: The heating temperature of the intermediate billet is set to 950° C., and the forging process is performed according to the preset strain rate range to perform an equivalent strain distribution numerical simulation, and the actual strain distribution rate of the TA15 titanium alloy frame beam forging is analyzed.

10. A TA15 titanium alloy frame beam, characterized in that: The TA15 titanium alloy frame beam is manufactured by the forging method described in any one of claims 1-9.

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