TA15 titanium alloy single-phase region forging method based on finite element analog simulation

Abstract

The invention relates to a TA15 titanium alloy single-phase region forging method based on finite element analog simulation. The TA15 titanium alloy single-phase region forging method comprises the following steps that S1, a TA15 titanium alloy cast ingot is smelted; s2, cogging and heating the cast ingot; s3, cogging and forging; s4, collecting and calculating a heat exchange coefficient; s5, heating schedule simulation calculation; s6, heating in a single-phase region; s7, forging process simulation calculation; s8, single-phase region forging; and S9, tissue detection. According to the method, accurate calculation is conducted through the core temperature rise effect generated in the thermal deformation process, the heating system is optimized, the problems of surface oxidation, beta embrittlement and the like of the blank due to too long heating time are avoided, meanwhile, the heating energy consumption cost is remarkably reduced, and the production efficiency is improved.

Description

Technical Field

[0001] This invention relates to the field of titanium processing technology, and in particular to a forging method for TA15 titanium alloy in the single-phase region based on finite element simulation. Background Technology

[0002] TA15 alloy is a general-purpose high-aluminum equivalent near-alpha alloy with a nominal composition of Ti-6Al-2Zr-1Mo-1V and a phase transformation temperature of 970–1010℃. This alloy is mainly used to manufacture structural parts, load-bearing structural components, and some important structural parts with high temperatures and complex stresses that operate for extended periods below 500℃, such as various engine blades, casings, various sheet metal parts, beams, joints, large wall panels, and welded load-bearing frames.

[0003] In the forming of these titanium alloy structural parts, heating and forging technologies play a crucial role. Due to the inherent microstructure and structural characteristics of TA15 titanium alloy, its most prominent features during hot working are high deformation resistance and chemical reactivity. This leads to the following common problems during heating and plastic deformation: In the single-phase region, precise control of the heating time is difficult. If the heating time is too short, the billet cannot be fully heated, affecting product quality. If the heating time is too long, the billet surface will oxidize severely, easily cracking and prone to β-embrittlement, while also consuming a large amount of energy, adding unnecessary costs. Furthermore, after heating, the billet undergoes upsetting deformation. If the deformation is too large and the forging speed is too fast, a temperature rise effect will occur in the core, leading to localized overheating. If the deformation is too small, the billet cannot be fully forged, resulting in poor deformation uniformity. If the forging speed is too slow, the overall temperature drop of the billet will be significant, also affecting quality. In summary, the narrow forging process window of TA15 titanium alloy in the single-phase region leads to problems such as high cost and low efficiency. Currently, there is an urgent need to find a way to address the shortcomings of existing technologies.

[0004] A technical solution developed by the Northwest Nonferrous Metals Research Institute, entitled "A Method for Improving Cracking During Forging of Heat-Resistant Titanium Alloy Billets," has been published under the number CN 113290180 A. This method effectively refines the grain structure of heat-resistant titanium alloy billets after forging, improves the cracking phenomenon during forging, eliminates the need for extensive grinding of surface cracks, and simultaneously increases the efficiency and yield of forging. However, this method uses an empirical formula for heating in the single-phase region: holding time t = (1~1.2)D, which cannot accurately predict the temperature change of the billet during the heating process.

[0005] A technical solution developed by China Aluminum Shenyang Nonferrous Metals Processing Co., Ltd., entitled "A Forging Method for Large-Diameter High-Quality TA15 Bars," has been published under the number CN 116460237 A. This method employs a simplified forging process utilizing a coating for oxidation prevention, asbestos wrapping for slow cooling, segmented heating, and a two-stage high- and low-temperature process to ultimately achieve precise control over the uniformity of the forged bar's microstructure and batch stability. However, this method requires multiple tempering and reheating processes to ensure core heating, inevitably increasing the number of steps and costs. Furthermore, the coating and asbestos will affect heat transfer.

[0006] A technical solution developed by the Institute of Metal Research, Chinese Academy of Sciences, entitled "A Method for Suppressing Forging Cracking of High-Temperature Titanium Alloys by Combining Finite Element Simulation Analysis," is published under the number CN 116306106 A. This method, combining finite element simulation and experimental analysis, can significantly reduce the overall tendency and degree of localized surface cracking in high-temperature titanium alloy forging, greatly improving hot working efficiency and yield. However, the simulation portion of this method only includes furnace exit transfer, upsetting, and drawing; it does not simulate the billet heating process.

[0007] The paper, titled "Forging Process of TA15 Titanium Alloy in the α+β Two-Phase Region Based on Machining Map Technology," proposes a method that combines thermal simulation experiments to construct a hot working map. This method predicts the machinability of TA15 titanium alloy under different deformation temperatures and rates, ultimately optimizing process parameters and providing a reasonable machining range. However, this method is only applicable to forging in the two-phase region; its feasibility for guiding heating and forging processes in the high-temperature single-phase region remains unknown.

[0008] The paper, titled "Grain Refinement Mechanism and Mechanical Properties of TA15 Titanium Alloy by Isothermal Multidirectional Forging," proposes a method for preparing TA15 titanium alloy with refined grains and good mechanical properties using warm-heated MDIF multidirectional forging technology. The model was validated using finite element method (FEM) simulation to calculate the strain field distribution. However, this method requires the alloy to be prepared under relatively ideal conditions, and the isothermal state is difficult to achieve in industrial applications. Furthermore, the sample size is relatively small, only 15 mm × 15 mm × 30 mm, which limits its application in large industrial bars.

[0009] Based on the shortcomings of the existing technology, this invention proposes a heating method for the β-phase region of titanium alloys based on finite element simulation. It formulates a heating and forging process scheme for TA15 titanium alloy in the single-phase region, and uses the core temperature rise effect generated during hot deformation to perform accurate calculations, optimize the heating regime, and avoid problems such as surface oxidation and β embrittlement of the billet caused by excessive heating time. At the same time, it significantly saves heating energy consumption costs and improves production efficiency. Summary of the Invention

[0010] To address the aforementioned problems, the present invention aims to provide a TA15 titanium alloy single-phase region forging method based on finite element simulation. By combining finite element simulation, a visualization model is established, and the heating regime is rationally optimized and the forging process is formulated by calculating the temperature distribution and changes of the billet during the single-phase region heating process.

[0011] The technical solution adopted in this invention is as follows: The present invention proposes a TA15 titanium alloy single-phase region forging method based on finite element simulation, comprising the following steps: S1, melting TA15 titanium alloy ingot; S2, ingot billet heating; S3, billet forging; S4, heat transfer coefficient acquisition and calculation; S5, heating regime simulation calculation; S6, single-phase region heating; S7, forging process simulation calculation; S8, single-phase region forging; S9, microstructure detection.

[0012] Furthermore, in step S1, the mass percentage of the alloy composition satisfies the following conditions: Al content is 6.4%~6.8%; Mo content is 1.5%~1.9%; V content is 1.9%~2.4%; and Zr content is 1.6%~2.4%.

[0013] Furthermore, step S2 includes: using a gas furnace to heat the TA15 titanium alloy ingot to 1140℃~1160℃, the heating system adopts a segmented heating method, wherein the preheating time is 120min~160min, the preheating temperature is 800℃~850℃, the heating time is 120min~160min, the temperature uniformity time is 180min~240min, and the ingot diameter is 700~800mm.

[0014] Furthermore, step S3 includes: forging and elongating the heated ingot to obtain a billet with a height-to-diameter ratio of 1 / 1.8 to 1 / 2, and an elongation deformation of 20% to 40%; finally obtaining a square billet with a cross-sectional size of 530mm to 570mm.

[0015] Furthermore, step S4 includes: using thermocouples and a monitoring instrument to collect the temperature rise curve of the billet in the electric heating furnace, and using simulation software to calculate the heat transfer coefficient of the electric heating furnace at different temperatures, with the coefficient varying from 20℃ to 1100℃.

[0016] Furthermore, step S5 includes: using finite element simulation software to calculate the heating regime when the billet reaches 1100℃ for complete heat penetration, wherein the preheating temperature is 800℃~850℃, and calculating the following parameters: t1 is recorded as the preheating time, t2 as the heating time, t3 as the holding time when the core temperature of the billet reaches 1090℃~1092℃, and t4 as the holding time when the billet is completely heated through; wherein t1 is 60min~90min, t2 is 90min~120min, t3 is 150min~180min, and t4 ≥ 240min.

[0017] Furthermore, step S6 includes: heating the billet in a single-phase region using an electric heating furnace at a heating temperature of 1050℃~1100℃. Based on the simulation calculation results of step S5, the heating regime uses t1 as the preheating time and 800℃~850℃, t2 as the heating time, and t3 as the holding time to perform segmented heating.

[0018] Furthermore, step S7 includes: using finite element simulation software to perform upsetting and drawing simulation on the billet, calculating the temperature rise effect in the core of the billet, and the simulation parameters include deformation temperature, deformation amount, and deformation speed; calculating the process parameters when the core temperature rise reaches 8℃~10℃; wherein, the upsetting deformation amount is 42%~45%, and the deformation speed is 30mm / s~50mm / s.

[0019] Furthermore, step S8 includes: based on the simulation results of step S7, performing single-phase forging on the heated billet, including one straight upsetting and two reversing upsetting to finally obtain an octagonal billet; wherein, the axial upsetting deformation is 42%~45%, the radial diagonal flattening deformation is 10%~20%, and the deformation speed is 30mm / s~50mm / s, and the original axial direction is kept consistent after the two reversing forgings.

[0020] Furthermore, step S9 includes: grinding the surface of the forged billet to remove surface cracks and defects, and cutting and sampling at the D / 4 position of the billet head and tail for high-magnification metallographic analysis to determine that the billet has no overheating or burning defects, thereby completing the preparation of the single-phase region forged billet of TA15 titanium alloy.

[0021] Compared with the prior art, the present invention has the following advantages: This invention combines finite element simulation calculations to formulate a heating and forging process scheme for TA15 titanium alloy in the single-phase region. It utilizes the core temperature rise effect generated during hot deformation for precise calculation, optimizes the heating regime, avoids problems such as surface oxidation and β embrittlement of billets caused by excessive heating time, and significantly saves heating energy consumption costs and improves production efficiency. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the temperature field of the billet after heat preservation at t3 in Example 1; Figure 2 This is a schematic diagram showing the temperature rise of the core of the billet after upsetting deformation in Example 1; Figure 3 This is a high-magnification microstructure diagram of the single-phase region forging process in Example 1. Detailed Implementation

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] The present invention proposes a single-phase forging method for TA15 titanium alloy based on finite element simulation, comprising the following steps: S1. Melt TA15 titanium alloy ingots; wherein the alloy composition by mass percentage meets the following conditions: Al content is 6.4%~6.8%; Mo content is 1.5%~1.9%; V content is 1.9%~2.4%; Zr content is 1.6%~2.4%.

[0025] S2. Ingot Heating: A gas-fired furnace is used to heat the TA15 titanium alloy ingot to 1140℃~1160℃. The heating process in S2 is segmented, with a preheating time of 120min~160min, a preheating temperature of 800℃~850℃, a heating time of 120min~160min, a homogenization time of 180min~240min, and an ingot diameter of 700mm~800mm.

[0026] S3. Forging: The heated ingot is forged and drawn to obtain a billet with a height-to-diameter ratio of (1:1.8) to (1:2), and the drawing deformation is 20% to 40%. Finally, a square billet with a cross-sectional size of 530mm to 570mm is obtained.

[0027] S4. Heat transfer coefficient acquisition and calculation: The temperature rise curve of the billet in the electric heating furnace is acquired by thermocouples and inspection instrument. The heat transfer coefficient of the electric heating furnace at different temperatures is obtained by simulation software. The coefficient varies from 20℃ to 1100℃.

[0028] S5. Heating Regime Simulation Calculation: Using finite element simulation software, the heating regime for fully heated billet to 1100℃ was calculated, with a preheating temperature of 800℃~850℃. The following parameters were calculated: t1 is the preheating time, t2 is the heating time, t3 is the holding time when the billet core temperature reaches 1090℃~1092℃, and t4 is the holding time when the billet is fully heated. The calculations show that in S5, t1 is 60min~90min, t2 is 90min~120min, t3 is 150min~180min, and t4 ≥ 240min.

[0029] S6. Single-phase heating: The billet is heated in a single-phase zone using an electric heating furnace at a temperature of 1050℃~1100℃. Based on the simulation results of S5, the heating regime uses t1 as the preheating time and 800℃~850℃ as the preheating temperature, t2 as the heating time, and t3 as the holding time for segmented heating.

[0030] S7. Forging Process Simulation Calculation: Finite element simulation software is used to simulate the upsetting and drawing of the billet, calculating the temperature rise effect in the core of the billet. The simulation parameters mainly include deformation temperature, deformation amount, and deformation rate. The process parameters when the core temperature rise reaches 8℃~10℃ are calculated. The calculation shows that the upsetting deformation amount in S7 is 42%~45%, and the deformation rate is 30mm / s~50mm / s.

[0031] S8. Single-phase forging: Based on the simulation results of S7, the heated billet is forged in a single-phase region, including one straight upsetting and two reversing upsetting processes, ultimately obtaining an octagonal billet. In S8, the axial upsetting deformation is 42%~45%, the radial diagonal flattening deformation is 10%~20%, and the deformation speed is 30mm / s~50mm / s. The two reversing forging processes ensure that the original axial direction is consistent before and after.

[0032] S9. Microstructure Inspection: The surface of the forged billet is ground to remove surface cracks and defects, and samples are cut and taken from the D / 4 position of the beginning and end of the billet for high-magnification metallographic microstructure inspection to confirm that the billet has no defects such as overheating or burning, thus completing the preparation of the single-phase region forging billet of TA15 titanium alloy.

[0033] When forging TA15 in the single-phase region using traditional methods, due to the temperature rise effect in the core of the titanium alloy, the axial upsetting process often employs methods such as split hammering, light upsetting, and slow forging to avoid overheating of the core.

[0034] The core principle of this invention lies in using finite element simulation for visual calculations to shorten heating time and control the core temperature range of the billet. By simulating deformation process parameters, the core temperature rise effect is used to precisely compensate for the temperature rise in the billet core, thereby completing the forging of the alloy single-phase region. This method effectively avoids the core temperature rise effect while significantly saving energy consumption and costs, greatly improving work efficiency, and showing no structural defects after forging.

[0035] The present invention will be further illustrated below through specific embodiments: Example 1 S1. Melting TA15 titanium alloy ingots. The alloy composition by mass percentage meets the following requirements: Al content 6.74%; Mo content 1.68%; V content 2.16%; Zr content 2.25%.

[0036] S2. Ingot Heating. A gas-fired furnace is used to heat the TA15 titanium alloy ingot to 1150℃. The heating process in S2 is segmented, with a preheating time of 150 min, a preheating temperature of 850℃, a heating time of 150 min, a uniform temperature time of 180 min, and an ingot diameter of 750 mm.

[0037] S3. Forging: The heated ingot is forged and drawn to obtain a billet with a height-to-diameter ratio of 1:1.8 and a drawing deformation of 30%. The final result is a square billet with a cross-sectional dimension of 550mm.

[0038] S4. Heat transfer coefficient acquisition and calculation. Thermocouples and a monitoring instrument are used to collect the temperature rise curve of the billet in the electric heating furnace. The heat transfer coefficient of the electric heating furnace at different temperatures is obtained by simulation software.

[0039] S5. Heating regime simulation calculation. Finite element simulation software was used to calculate the heating regime when the billet reaches 1100℃ for complete heat penetration, with a preheating temperature of 850℃. The following parameters were calculated: t1 is the preheating time, t2 is the heating time, t3 is the holding time when the billet core temperature reaches 1090℃, and t4 is the holding time when the billet is fully heated. The calculations show that in S5, t1 is 90 min, t2 is 90 min, t3 is 150 min, and t4 is 260 min.

[0040] S6. Single-phase heating. The billet is heated in a single-phase zone using an electric heating furnace at a temperature of 1100℃. Based on the simulation results of S5, the heating regime uses t1 as the preheating time and t2 as the heating time, and t3 as the holding time, to perform segmented heating.

[0041] S7. Forging Process Simulation Calculation. Finite element simulation software was used to simulate the upsetting and drawing of the billet, calculating the temperature rise effect in the billet's core. The simulation parameters mainly included deformation temperature, deformation amount, and deformation rate. The process parameters were calculated when the core temperature rise reached 10℃. The calculation showed that the upsetting deformation amount in S7 was 42%, and the deformation rate was 30 mm / s.

[0042] S8. Single-phase forging. Based on the simulation results of S7, the heated billet is subjected to single-phase forging, including one straight upsetting and drawing and two reversing upsetting and drawing operations, ultimately obtaining an octagonal billet. In S8, the axial upsetting deformation is 42%, the radial diagonal flattening deformation is 10%, and the deformation rate is 30 mm / s. The two reversing forging operations ensure that the original axial direction is consistent before and after.

[0043] S9. Microstructure Inspection. The forged billet is surface-ground to remove surface cracks and defects. Samples are taken from the D / 4 position at the beginning and end of the billet for high-magnification metallographic microstructure inspection. The final result shows that the alloy microstructure is good, with uniformly distributed lamellar and basketweave structures, and no obvious overheating or burning defects.

[0044] Example 2 S1. Melting TA15 titanium alloy ingots. The alloy composition in S1, by mass percentage, satisfies the following: Al content 6.72%; Mo content 1.69%; V content 2.14%; Zr content 2.28%.

[0045] S2. Ingot Heating. A gas-fired furnace is used to heat the TA15 titanium alloy ingot to 1150℃. The heating process in S2 is segmented, with a preheating time of 150 min, a preheating temperature of 800℃, a heating time of 150 min, a uniform temperature time of 180 min, and an ingot diameter of 750 mm.

[0046] S3. Forging: The heated ingot is forged and drawn to obtain a billet with a height-to-diameter ratio of 1:1.8 and a drawing deformation of 30%. The final result is a square billet with a cross-sectional dimension of 550mm.

[0047] S4. Heat transfer coefficient acquisition and calculation. Thermocouples and a monitoring instrument are used to collect the temperature rise curve of the billet in the electric heating furnace. The heat transfer coefficient of the electric heating furnace at different temperatures is obtained by simulation software.

[0048] S5. Heating regime simulation calculation. Finite element simulation software was used to calculate the heating regime when the billet reaches 1100℃ for complete heat penetration, with a preheating temperature of 800℃. The following parameters were calculated: t1 is the preheating time, t2 is the heating time, t3 is the holding time when the billet core temperature reaches 1090℃, and t4 is the holding time when the billet is fully heated. The calculations show that in S5, t1 is 90 min, t2 is 90 min, t3 is 150 min, and t4 is 260 min.

[0049] S6. Single-phase heating. The billet is heated in a single-phase zone using an electric heating furnace at a temperature of 1100℃. Based on the simulation results of S5, the heating regime uses t1 as the preheating time and t2 as the heating time, and t3 as the holding time, to perform segmented heating.

[0050] S7. Forging Process Simulation Calculation. Finite element simulation software was used to simulate the upsetting and drawing of the billet, calculating the temperature rise effect in the billet's core. The simulation parameters mainly included deformation temperature, deformation amount, and deformation rate. The process parameters were calculated when the core temperature rise reached 10℃. The calculation showed that the upsetting deformation amount in S7 was 43%, and the deformation rate was 40 mm / s.

[0051] S8. Single-phase forging. Based on the simulation results of S7, the heated billet is subjected to single-phase forging, including one straight upsetting and drawing and two reversing upsetting and drawing operations, ultimately obtaining an octagonal billet. In S8, the axial upsetting deformation is 42%, the radial diagonal flattening deformation is 15%, and the deformation rate is 40 mm / s. The two reversing forging operations ensure that the original axial direction is consistent.

[0052] S9. Microstructure Inspection. The forged billet is surface-ground to remove surface cracks and defects. Samples are taken from the D / 4 position at the beginning and end of the billet for high-magnification metallographic microstructure inspection. The final result shows that the alloy microstructure is good, with uniformly distributed lamellar and basketweave structures, and no obvious overheating or burning defects.

[0053] Example 3 S1. Melting TA15 titanium alloy ingots. The alloy composition in S1, by mass percentage, satisfies the following: Al content 6.68%; Mo content 1.74%; V content 2.26%; Zr content 2.18%.

[0054] S2. Ingot Heating. A gas-fired furnace is used to heat the TA15 titanium alloy ingot to 1160℃. The heating process in S2 is segmented, with a preheating time of 160 min, a preheating temperature of 850℃, a heating time of 160 min, a uniform temperature time of 210 min, and an ingot diameter of 750 mm.

[0055] S3. Forging: The heated ingot is forged and drawn to obtain a billet with a height-to-diameter ratio of 1:1.8 and a drawing deformation of 40%. The final result is a square billet with a cross-sectional dimension of 570mm.

[0056] S4. Heat transfer coefficient acquisition and calculation. Thermocouples and a monitoring instrument are used to collect the temperature rise curve of the billet in the electric heating furnace. The heat transfer coefficient of the electric heating furnace at different temperatures is obtained by simulation software.

[0057] S5. Heating regime simulation calculation. Finite element simulation software was used to calculate the heating regime when the billet reaches 1100℃ for complete heat penetration, with a preheating temperature of 850℃. The following parameters were calculated: t1 is the preheating time, t2 is the heating time, t3 is the holding time when the billet core temperature reaches 1092℃, and t4 is the holding time when the billet is fully heated. The calculations show that in S5, t1 is 90 min, t2 is 120 min, t3 is 180 min, and t4 is 280 min.

[0058] S6. Single-phase heating. The billet is heated in a single-phase zone using an electric heating furnace at a temperature of 1080℃. Based on the simulation results of S5, the heating regime uses t1 as the preheating time and t2 as the heating time, and t3 as the holding time, to perform segmented heating.

[0059] S7. Forging Process Simulation Calculation. Finite element simulation software was used to simulate the upsetting and drawing of the billet, calculating the temperature rise effect in the billet's core. The simulation parameters mainly included deformation temperature, deformation amount, and deformation rate. The process parameters when the core temperature rise reached 8℃ were calculated. The calculation showed that the upsetting deformation amount in S7 was 42%, and the deformation rate was 50 mm / s.

[0060] S8. Single-phase forging. Based on the simulation results of S7, the heated billet is subjected to single-phase forging, including one straight upsetting and two reversing upsetting processes, ultimately obtaining an octagonal billet. In S8, the axial upsetting deformation is 42%, the radial diagonal flattening deformation is 20%, and the deformation rate is 50 mm / s. The two reversing forging processes ensure that the original axial direction remains consistent.

[0061] S9. Microstructure Inspection. The forged billet is surface-ground to remove surface cracks and defects. Samples are taken from the D / 4 position at the beginning and end of the billet for high-magnification metallographic microstructure inspection. The final result shows that the alloy microstructure is good, with uniformly distributed lamellar and basketweave structures, and no obvious overheating or burning defects.

[0062] Example 4 S1. Melting TA15 titanium alloy ingots. The alloy composition in S1, by mass percentage, satisfies the following: Al content 6.78%; Mo content 1.62%; V content 2.05%; Zr content 2.12%.

[0063] S2. Ingot Heating. A gas-fired furnace is used to heat the TA15 titanium alloy ingot to 1160℃. The heating process in S2 is segmented, with a preheating time of 140 min, a preheating temperature of 800℃, a heating time of 140 min, a uniform temperature time of 220 min, and an ingot diameter of 750 mm.

[0064] S3. Forging: The heated ingot is forged and drawn to obtain a billet with a height-to-diameter ratio of 1:1.8 and a drawing deformation of 25%. The final result is a square billet with a cross-sectional dimension of 530mm.

[0065] S4. Heat transfer coefficient acquisition and calculation. Thermocouples and a monitoring instrument are used to collect the temperature rise curve of the billet in the electric heating furnace. The heat transfer coefficient of the electric heating furnace at different temperatures is obtained by simulation software.

[0066] S5. Heating regime simulation calculation. Finite element simulation software was used to calculate the heating regime when the billet reaches 1100℃ for complete heat penetration, with a preheating temperature of 800℃. The following parameters were calculated: t1 is the preheating time, t2 is the heating time, t3 is the holding time when the billet core temperature reaches 1092℃, and t4 is the holding time when the billet is fully heated. The calculations show that in S5, t1 is 60 min, t2 is 90 min, t3 is 150 min, and t4 is 240 min.

[0067] S6. Single-phase heating. The billet is heated in a single-phase zone using an electric heating furnace at a temperature of 1080℃. Based on the simulation results of S5, the heating regime uses t1 as the preheating time and 800℃ as the preheating temperature, t2 as the heating time, and t3 as the holding time for segmented heating.

[0068] S7. Forging Process Simulation Calculation. Finite element simulation software was used to simulate the upsetting and drawing of the billet, calculating the temperature rise effect in the billet's core. The simulation parameters mainly included deformation temperature, deformation amount, and deformation rate. The process parameters when the core temperature rise reached 8℃ were calculated. The calculation showed that the upsetting deformation amount in S7 was 45%, and the deformation rate was 30 mm / s.

[0069] S8. Single-phase forging. Based on the simulation results of S7, the heated billet is subjected to single-phase forging, including one straight upsetting and drawing and two reversing upsetting and drawing operations, ultimately obtaining an octagonal billet. In S8, the axial upsetting deformation is 45%, the radial diagonal flattening deformation is 10%, and the deformation rate is 30 mm / s. The two reversing forging operations ensure that the original axial direction is consistent.

[0070] S9. Microstructure Inspection. The forged billet is surface-ground to remove surface cracks and defects. Samples are taken from the D / 4 position at the beginning and end of the billet for high-magnification metallographic microstructure inspection. The final result shows that the alloy microstructure is good, with uniformly distributed lamellar and basketweave structures, and no obvious overheating or burning defects.

[0071] Example 5 S1. Melting TA15 titanium alloy ingots. The alloy composition in S1, by mass percentage, satisfies the following: Al content 6.58%; Mo content 1.77%; V content 2.06%; Zr content 2.18%.

[0072] S2. Ingot Heating. A gas-fired furnace is used to heat the TA15 titanium alloy ingot to 1140℃. The heating process in S2 is segmented, with a preheating time of 130 min, a preheating temperature of 850℃, a heating time of 130 min, a uniform temperature time of 200 min, and an ingot diameter of 750 mm.

[0073] S3. Forging: The heated ingot is forged and drawn to obtain a billet with a height-to-diameter ratio of 1:1.8 and a drawing deformation of 30%. The final result is a square billet with a cross-sectional dimension of 540mm.

[0074] S4. Heat transfer coefficient acquisition and calculation. Thermocouples and a monitoring instrument are used to collect the temperature rise curve of the billet in the electric heating furnace. The heat transfer coefficient of the electric heating furnace at different temperatures is obtained by simulation software.

[0075] S5. Heating regime simulation calculation. Finite element simulation software was used to calculate the heating regime when the billet reaches 1100℃ for complete heat penetration, with a preheating temperature of 850℃. The following parameters were calculated: t1 is the preheating time, t2 is the heating time, t3 is the holding time when the billet core temperature reaches 1091℃, and t4 is the holding time when the billet is fully heated. The calculations show that in S5, t1 is 70 min, t2 is 100 min, t3 is 160 min, and t4 is 250 min.

[0076] S6. Single-phase heating. The billet is heated in a single-phase zone using an electric heating furnace at a temperature of 1050℃. Based on the simulation results of S5, the heating regime uses t1 as the preheating time and t2 as the heating time, and t3 as the holding time, to perform segmented heating.

[0077] S7. Forging Process Simulation Calculation. Finite element simulation software was used to simulate the upsetting and drawing of the billet, calculating the temperature rise effect in the billet's core. The simulation parameters mainly included deformation temperature, deformation amount, and deformation rate. The process parameters when the core temperature rise reached 9℃ were calculated. The calculation showed that the upsetting deformation amount in S7 was 44%, and the deformation rate was 40 mm / s.

[0078] S8. Single-phase forging. Based on the simulation results of S7, the heated billet is subjected to single-phase forging, including one straight upsetting and two reversing upsetting processes, ultimately obtaining an octagonal billet. In S8, the axial upsetting deformation is 44%, and the radial diagonal flattening deformation is 15%, with a deformation rate of 40 mm / s. The two reversing forging processes ensure that the original axial direction remains consistent.

[0079] S9. Microstructure Inspection. The forged billet is surface-ground to remove surface cracks and defects. Samples are taken from the D / 4 position at the beginning and end of the billet for high-magnification metallographic microstructure inspection. The final result shows that the alloy microstructure is good, with uniformly distributed lamellar and basketweave structures, and no obvious overheating or burning defects.

[0080] Example 6 S1. Melting TA15 titanium alloy ingots. The alloy composition in S1, by mass percentage, satisfies the following: Al content 6.62%; Mo content 1.54%; V content 2.21%; Zr content 2.19%.

[0081] S2. Ingot Heating. A gas-fired furnace is used to heat the TA15 titanium alloy ingot to 1140℃. The heating process in S2 is segmented, with a preheating time of 160 min, a preheating temperature of 800℃, a heating time of 160 min, a uniform temperature time of 240 min, and an ingot diameter of 750 mm.

[0082] S3. Forging: The heated ingot is forged and drawn to obtain a billet with a height-to-diameter ratio of 1:1.8 and a drawing deformation of 35%. The final result is a square billet with a cross-sectional dimension of 560mm.

[0083] S4. Heat transfer coefficient acquisition and calculation. Thermocouples and a monitoring instrument are used to collect the temperature rise curve of the billet in the electric heating furnace. The heat transfer coefficient of the electric heating furnace at different temperatures is obtained by simulation software.

[0084] S5. Heating regime simulation calculation. Finite element simulation software was used to calculate the heating regime when the billet reaches 1100℃ for complete heat penetration, with a preheating temperature of 800℃. The following parameters were calculated: t1 is the preheating time, t2 is the heating time, t3 is the holding time when the billet core temperature reaches 1091℃, and t4 is the holding time when the billet is fully heated. The calculations show that in S5, t1 is 80 min, t2 is 110 min, t3 is 170 min, and t4 is 270 min.

[0085] S6. Single-phase heating. The billet is heated in a single-phase zone using an electric heating furnace at a temperature of 1050℃. Based on the simulation results of S5, the heating regime uses t1 as the preheating time and 800℃ as the preheating temperature, t2 as the heating time, and t3 as the holding time for segmented heating.

[0086] S7. Forging Process Simulation Calculation. Finite element simulation software was used to simulate the upsetting and drawing of the billet, calculating the temperature rise effect in the billet's core. The simulation parameters mainly included deformation temperature, deformation amount, and deformation rate. The process parameters when the core temperature rise reached 9℃ were calculated. The calculation showed that the upsetting deformation amount in S7 was 45%, and the deformation rate was 50 mm / s.

[0087] S8. Single-phase forging. Based on the simulation results of S7, the heated billet is forged in a single-phase region, including one straight upsetting and two reversing upsetting processes, ultimately obtaining an octagonal billet. In S8, the axial upsetting deformation is 45%, and the radial diagonal flattening deformation is 20%, with a deformation rate of 50 mm / s for both processes. The two reversing forging processes ensure that the original axial direction remains consistent.

[0088] S9. Microstructure Inspection. The forged billet is surface-ground to remove surface cracks and defects. Samples are taken from the D / 4 position at the beginning and end of the billet for high-magnification metallographic microstructure inspection. The final result shows that the alloy microstructure is good, with uniformly distributed lamellar and basketweave structures, and no obvious overheating or burning defects.

[0089] The heating regime and forging process of the above embodiments are shown in the table below:

[0090] All matters not covered in this invention are common knowledge.

[0091] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A forging method for TA15 titanium alloy in the single-phase region based on finite element simulation, characterized in that, The method includes the following steps: S1, melting TA15 titanium alloy ingots; S2, heating the ingot during billet preparation; S3, forging the billet; S4, collecting and calculating the heat transfer coefficient; S5, simulating and calculating the heating regime; S6, heating in the single-phase region; S7, simulating and calculating the forging process; S8, forging in the single-phase region; S9, microstructure detection.

2. The forging method for TA15 titanium alloy single-phase region based on finite element simulation according to claim 1, characterized in that: In step S1, the alloy composition by mass percentage satisfies the following conditions: Al content is 6.4%~6.8%; Mo content is 1.5%~1.9%; V content is 1.9%~2.4%; Zr content is 1.6%~2.4%.

3. The forging method for TA15 titanium alloy single-phase region based on finite element simulation according to claim 1, characterized in that: Step S2 includes: using a gas furnace to heat the TA15 titanium alloy ingot to 1140℃~1160℃, the heating system adopts a segmented heating method, wherein the preheating time is 120min~160min, the preheating temperature is 800℃~850℃, the heating time is 120min~160min, the temperature uniformity time is 180min~240min, and the ingot diameter is 700~800mm.

4. The forging method for TA15 titanium alloy single-phase region based on finite element simulation according to claim 1, characterized in that: Step S3 includes: forging and drawing the heated ingot to obtain a billet with a height-to-diameter ratio of 1 / 1.8 to 1 / 2, and a drawing deformation of 20% to 40%; finally, a square billet with a cross-sectional size of 530mm to 570mm is obtained.

5. The forging method for TA15 titanium alloy single-phase region based on finite element simulation according to claim 1, characterized in that: Step S4 includes: using thermocouples and a monitoring instrument to collect the temperature rise curve of the billet in the electric heating furnace, and using simulation software to calculate the heat transfer coefficient of the electric heating furnace at different temperatures. The coefficient varies from 20℃ to 1100℃.

6. The forging method for TA15 titanium alloy single-phase region based on finite element simulation according to claim 5, characterized in that: Step S5 includes: using finite element simulation software to calculate the heating regime when the billet reaches 1100℃ and is fully heated through, wherein the preheating temperature is 800℃~850℃, and calculating the following parameters: t1 is the preheating time, t2 is the heating time, t3 is the holding time when the core temperature of the billet reaches 1090℃~1092℃, and t4 is the holding time when the billet is fully heated through; wherein t1 is 60min~90min, t2 is 90min~120min, t3 is 150min~180min, and t4 ≥ 240min.

7. The forging method for TA15 titanium alloy single-phase region based on finite element simulation according to claim 6, characterized in that: Step S6 includes: heating the billet in a single-phase region using an electric heating furnace at a heating temperature of 1050℃~1100℃. Based on the simulation calculation results of step S5, the heating regime uses t1 as the preheating time and 800℃~850℃ as the preheating temperature, t2 as the heating time, and t3 as the holding time to perform segmented heating.

8. The forging method for TA15 titanium alloy single-phase region based on finite element simulation according to claim 1, characterized in that: Step S7 includes: using finite element simulation software to perform upsetting and drawing simulation on the billet, calculating the temperature rise effect in the core of the billet, and the simulation parameters include deformation temperature, deformation amount, and deformation speed; calculating the process parameters when the core temperature rise reaches 8℃~10℃; wherein, the upsetting deformation amount is 42%~45%, and the deformation speed is 30mm / s~50mm / s.

9. The forging method for TA15 titanium alloy single-phase region based on finite element simulation according to claim 8, characterized in that: Step S8 includes: based on the simulation results of step S7, the heated billet is forged in a single-phase region, including one straight upsetting and two reversing upsettings, to finally obtain an octagonal billet; wherein, the axial upsetting deformation is 42%~45%, the radial diagonal flattening deformation is 10%~20%, and the deformation speed is 30mm / s~50mm / s, and the original axial direction is kept consistent after the two reversing forgings.

10. The forging method for TA15 titanium alloy in single-phase region based on finite element simulation according to claim 1, characterized in that: Step S9 includes: grinding the surface of the forged billet to remove surface cracks and defects, and cutting and sampling at the D / 4 position of the billet head and tail for high-magnification metallographic structure detection to confirm that the billet has no overheating or burning defects, thereby completing the preparation of the single-phase region forging billet of TA15 titanium alloy.

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