A forging process for TC11 titanium alloy disc forgings
By optimizing heating temperature and deformation control, designing multiple deformation steps, and performing pretreatment and water cooling between steps, the problem of uneven microstructure in TC11 titanium alloy forgings was solved, achieving a uniform and fine microstructure in the forgings and improving their quality and service life.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2022-12-14
- Publication Date
- 2026-04-03
AI Technical Summary
The existing forging process for TC11 titanium alloy forgings is difficult to guarantee the uniformity of the microstructure, resulting in severe bright line microstructure, and the traditional process has limited improvement on the coarse microstructure.
By optimizing heating temperature and deformation control, designing multiple deformation steps, and performing pretreatment between steps, combined with rapid water cooling and heat preservation treatment, the microstructure is gradually refined to ensure the uniformity of the billet.
This achieves a uniform and fine microstructure in the forgings, avoiding the inhomogeneity of coarse microstructures and improving the quality stability and service life of the forgings.
Abstract
Description
Technical fields:
[0001] This invention belongs to the field of titanium alloy hot working technology, and relates to a billet forging process for TC11 titanium alloy disc forgings. Background technology:
[0002] TC11 titanium alloy forgings are widely used in aero-engines, primarily in rotating components. They require high microstructure and performance to meet long-cycle life requirements, with a uniform, fine-grained microstructure being a critical condition. Conventional forging processes typically only consider standard requirements during the design phase, neglecting the uniformity of the forgings. Some TC11 titanium alloy forgings exhibit bright lines during final full-surface corrosion, and high-magnification analysis reveals residual, slightly coarse, elongated, or large α-grain structures. However, these structures still meet standard requirements to a certain extent and are therefore often overlooked by technical personnel.
[0003] When the original microstructure of the bar stock is relatively coarse, traditional forging processes have limited effect on improving the microstructure and uniformity is difficult to guarantee, resulting in a more severe bright line microstructure. Solving this problem has become the key to improving the quality of TC11 titanium alloy forgings. Summary of the Invention
[0004] The technical problem this invention aims to solve is as follows: By optimizing the heating temperature and deformation control of TC11 titanium alloy, the invention designs multiple deformation steps, with pre-treatment steps between these steps on the billet. This effectively stabilizes the microstructure and prepares the microstructure for subsequent heating homogenization. Post-forging water cooling helps store distortion energy, further refining the microstructure and providing certain process conditions for microstructure homogenization, thus fully ensuring the uniform and fine microstructure of the forging. The deformation steps are designed with a certain gradient, which helps to gradually refine the microstructure and avoids the inhomogeneity caused by large deformation in a single step when the microstructure is coarse.
[0005] Technical solution:
[0006] A forging process for TC11 titanium alloy disc forgings includes the following steps:
[0007] Heat the TC11 titanium alloy rod material segment to 0-30℃ above the phase transformation point, and calculate the holding time as 0.5-1.0 min / mm;
[0008] After the TC11 titanium alloy bar material segment is heated at the specified temperature and held at that temperature for the specified time, it should be rapidly water-cooled within 15 seconds after being taken out of the furnace.
[0009] The billet that has undergone the above treatment is heated multiple times to 0-50°C below the phase transformation point and held at that temperature to allow the billet to recrystallize statically. After each heating, the billet is taken out of the furnace and forged. The forging process should be completed within 1 minute with strict control.
[0010] The temperature decreases with each heating cycle compared to the previous heating cycle.
[0011] The temperature difference between two adjacent static recrystallization heating temperatures is 10–15°C.
[0012] The static recrystallization cycle is 2 to 4 times, and the deformation increases as the static recrystallization heating temperature decreases.
[0013] When the static recrystallization cycle is 2, the bar material segment or billet that has undergone the above treatment is repeatedly heated to 0-50°C below the phase transformation point and held at that temperature to allow for static recrystallization; after each heating, it is forged, including:
[0014] The bar material segment that has undergone the above treatment is reheated to 0-30°C below the phase transformation point, and the holding time is calculated at 0.8-1.3 min / mm; it is then forged after being taken out of the furnace, with a deformation of 20%-40%, and the forging should be completed within 1 minute with strict control, and the final forging temperature should be controlled at no less than 900°C; it is then rapidly water-cooled within 15 seconds after forging; the water-cooled billet is then heated to 850-900°C, and after being thoroughly heated, it is held at that temperature for no less than 2 hours, and then air-cooled;
[0015] The billet that has undergone the above forging deformation and treatment is reheated to 30-50°C below the phase transformation point, and the holding time is calculated at 0.8-1.3 min / mm; after being taken out of the furnace for forging, the deformation amount should be 40%-60%, and the forging time should be strictly controlled within 1 minute, with the final forging temperature controlled at no less than 850°C; the billet is rapidly water-cooled within 15 seconds after forging; the water-cooled billet is then heated to 800-850°C, and after being thoroughly heated, it is held at a temperature of no less than 2 hours, and then air-cooled.
[0016] When the static recrystallization cycle is 3, the bar material segment or billet that has undergone the above treatment is repeatedly heated to 0-50°C below the phase transformation point and held at that temperature to allow the billet to undergo static recrystallization; after each heating, it is forged, including:
[0017] The bar material segment that has undergone the above treatment is reheated to 0-20°C below the phase transformation point, and the holding time is calculated at 0.8-1.3 min / mm; it is then forged after being taken out of the furnace, with the deformation amount being 20%-40%, and the forging time being strictly controlled within 1 minute, with the final forging temperature controlled at no less than 900°C; it is then rapidly water-cooled within 15 seconds after forging; the water-cooled billet is then heated to 850-900°C, and after being thoroughly heated, it is held at that temperature for no less than 2 hours, and then air-cooled;
[0018] The billet that has undergone the above forging deformation and treatment is reheated to 20-40°C below the phase transformation point, and the holding time is calculated at 1.0-1.3 min / mm; after exiting the furnace, it is forged, and the deformation should be 30%-50%. The forging time should be strictly controlled within 1 minute, and the final forging temperature should be controlled at no less than 850°C; it is then rapidly water-cooled within 15 seconds after forging; the water-cooled billet is then heated to 830-850°C, and after thorough heating, it is held at that temperature for no less than 2 hours, and then air-cooled.
[0019] The billet that has undergone the above forging deformation and treatment is reheated to 30-50°C below the phase transformation point, and the holding time is calculated at 0.8-1.3 min / mm; after being taken out of the furnace for forging, the deformation amount should be 40%-60%, and the forging time should be strictly controlled within 1 minute, with the final forging temperature controlled at no less than 830°C; the billet is rapidly water-cooled within 15 seconds after forging; the water-cooled billet is then heated to 800-830°C, and after being thoroughly heated, it is held at that temperature for no less than 2 hours, and then air-cooled.
[0020] The water used for water cooling is flowing water, and the number of forgings cooled at one time should not be too large to ensure that the water temperature does not rise to 50°C during the cooling process.
[0021] Heating TC11 titanium alloy rod material segments to 0-30°C above the phase transformation point includes:
[0022] The TC11 titanium alloy rod material segment is first preheated to the preheating step, that is, 30-50℃ below the phase transformation point, and the holding time is calculated as 0.8-1.3min / mm.
[0023] The preheated rod material segment is heated to 0-30℃ above the phase transformation point, and the holding time is calculated as 0.5-1.0 min / mm.
[0024] The billet after forging and water cooling is then heated and held at a temperature 0-50°C lower than the final forging temperature after the forging process, and held for at least 2 hours before air cooling.
[0025] The final forging temperature should be controlled to be lower than the corresponding pre-forging heating temperature, with a difference not exceeding 80°C.
[0026] The beneficial effects of this invention are as follows: By optimizing the heating temperature and deformation control of TC11 titanium alloy, this invention designs multiple deformation steps, with pre-treatment steps between these steps for the billet. This has a good effect on stabilizing the microstructure and prepares the microstructure for subsequent heating homogenization. Post-forging water cooling helps store distortion energy, further refining the microstructure and providing certain process conditions for microstructure homogenization, thus fully ensuring the uniformity and fineness of the forging's microstructure. The deformation steps are designed with a certain gradient, which helps to gradually refine the microstructure and avoids the inhomogeneity caused by large deformation in a single step when the microstructure is coarse. Detailed Implementation
[0027] The following section uses the billet for a TC11 titanium alloy disc forging of a certain type of machine as an example. The process steps of the present invention will be described in detail below.
[0028] A forging process for TC11 titanium alloy disc forgings includes the following steps:
[0029] Step 1: Heat the TC11 titanium alloy rod material segment to 20°C above the phase transformation point, and calculate the holding time as 0.6 min / mm;
[0030] Step 2: After the TC11 titanium alloy rod material segment is heated to the specified temperature and held for the specified time, it should be taken out of the furnace and rapidly water-cooled within 15 seconds after being taken out of the furnace; this further inhibits the precipitation and growth of the α-matrix during the cooling process.
[0031] Step 3: Reheat the bar material segment that has undergone the above treatment to 20°C below the phase transformation point, and hold it for 1.0 min / mm; to achieve homogenization of the microstructure and conditions for plastic deformation before forging.
[0032] Step 4: After heating the TC11 titanium alloy bar material segment to the specified temperature and holding time, it is then removed from the furnace for forging. The deformation amount should be within 30%, and the forging time should be strictly controlled within 1 minute. The final forging temperature should be controlled at no less than 900℃. Sufficient deformation will make the microstructure of the TC11 bar material segment initially refined, forming the initial deformed billet.
[0033] Step 5: The initially deformed billet should be rapidly water-cooled within 15 seconds. This ensures that the distortion energy after deformation is stored and the initially refined microstructure is preserved.
[0034] Step 6: Heat the initially deformed billet to 850℃, hold it at that temperature for at least 2 hours after heating, and then air cool it. This further stabilizes the microstructure.
[0035] Step 7: Reheat the initial deformed billet after the above treatment to 30°C below the phase transformation point, and hold for 1.2 min / mm. The temperature is lower than that of the previous deformation step to avoid the growth of the original structure, while achieving the conditions for homogenization of the structure and plastic deformation before forging.
[0036] Step 8: Heating the initial deformed TC11 titanium alloy billet at the specified temperature and holding time before forging. The deformation amount should be 50%, and the forging time should be strictly controlled within 1 minute. The final forging temperature should be controlled at no less than 850℃ to form a secondary deformed billet. This step fully deforms the TC11 bar stock, further refining the microstructure obtained from the initial refinement. As the deformation amount increases and the temperature decreases, the microstructure after recrystallization in this step is finer than the initial refined microstructure.
[0037] Step 9: The secondary deformed billet should be rapidly water-cooled within 15 seconds after forging. This ensures that the distortion energy after deformation is stored, and the further refined microstructure is preserved.
[0038] Step 10: Heat the pre-treated, secondary-deformed billet to 820℃, maintain the temperature for at least 2 hours after heating, and then air-cool. This results in a fine, uniform, and stable microstructure in the final product, used for disc parts.
[0039] Further explanation: Step 1: During the heating process, a preheating step of 30–50°C below the phase transformation point is added, with a holding time of 1.2 min / mm. The purpose of setting the preheating step is to reduce the heating coefficient in the high-temperature stage and ensure that the original β grains do not grow excessively. In steps 2, 5, and 9, the water used for water cooling is flowing water, and the number of forgings cooled in one step should not be too large to ensure that the water temperature does not rise to 50°C during the cooling process.
[0040] In steps 6 and 10, the initial and secondary deformed billets, after forging and water cooling, are subsequently heated and held at a temperature 0-50°C lower than the final forging temperature of the corresponding deformation, with a holding time of no less than 2 hours, followed by air cooling. This effectively ensures that the deformed microstructure is fine, uniform, and stable. Step 4 should also ensure that the final forging temperature is lower than the heating temperature of the corresponding preceding step, with a difference not exceeding 80°C. Deformation at a higher initial forging temperature should be completed within a narrower temperature range, which is beneficial for the sufficiency of dynamic recrystallization and the control of microstructure uniformity in the deformed billet. Step 8 should also ensure that the final forging temperature is lower than the heating temperature of the corresponding preceding step, with a difference not exceeding 120°C. Building upon the initial deformation's refinement and uniformity of the microstructure, this reduces the difficulty of recrystallization. Deformation at a lower temperature allows for a wider temperature range to be appropriately expanded, and also provides a certain degree of timeliness for controlling the sufficiency of dynamic recrystallization and the uniformity of the microstructure in the billet.
Claims
1. A forging process for TC11 titanium alloy disc forgings, characterized in that, Includes the following steps: The TC11 titanium alloy rod material segment is heated to 0-30℃ above the phase transformation point, and the holding time is calculated at 0.5-1.0 min / mm. After the TC11 titanium alloy rod material segment is heated at the specified temperature and held for the specified time, it should be removed from the furnace and rapidly water-cooled within 15 seconds after being removed from the furnace. The processed billet is heated multiple times to 0-50°C below the phase transformation point and held at that temperature to allow for static recrystallization. After each heating, the billet is removed from the furnace and forged. The forging process should be completed within 1 minute with strict time control. The temperature of each heating should be gradually reduced compared to the previous heating temperature. When the static recrystallization cycle is 2, the treated bar segment or billet is repeatedly heated to 0–50°C below the phase transformation point and held at that temperature to allow for static recrystallization. After each heating, it is then forged, specifically including: Reheat the processed bar material segment to 0–30°C below the phase transformation point, and hold for 0.8–1.3 min / mm. Forge the bar material after it is removed from the furnace. The deformation should be 20%–40%, and the forging should be completed within 1 minute with strict control. The final forging temperature should be controlled at no less than 900°C. Water cool the bar material rapidly within 15 seconds after forging. Heat the water-cooled bar material to 850–900°C, hold it at that temperature for no less than 2 hours after it is fully heated, and then air cool it. The forged and processed billet is reheated to 30-50°C below the phase transformation point, and the holding time is calculated at 0.8-1.3 min / mm. After being taken out of the furnace for forging, the deformation amount should be 40%-60%, and the forging time should be strictly controlled within 1 minute. The final forging temperature should be controlled at no less than 850°C. The billet is then rapidly water-cooled within 15 seconds after forging. The water-cooled billet is then heated to 800-850°C, and after being thoroughly heated, it is held at that temperature for no less than 2 hours, and then air-cooled.
2. A forging process for billets used in TC11 titanium alloy disc forgings, characterized in that, Includes the following steps: The TC11 titanium alloy rod material segment is heated to 0-30℃ above the phase transformation point, and the holding time is calculated at 0.5-1.0 min / mm. After the TC11 titanium alloy rod material segment is heated at the specified temperature and held for the specified time, it should be removed from the furnace and rapidly water-cooled within 15 seconds after being removed from the furnace. The processed billet is heated multiple times to 0-50°C below the phase transformation point and held at that temperature to allow for static recrystallization. After each heating, the billet is removed from the furnace and forged. The forging process should be completed within 1 minute with strict time control. The temperature of each heating should be gradually reduced compared to the previous heating temperature. When the static recrystallization number is 3, the treated bar segment or billet is repeatedly heated to 0-50°C below the phase transformation point and held at that temperature to allow for static recrystallization. After each heating, the billet is forged, including: Reheat the processed bar material segment to 0–20°C below the phase transformation point, and hold for 0.8–1.3 min / mm. Forge the bar material after it is removed from the furnace. The deformation should be 20%–40%, and the forging time should be strictly controlled within 1 minute. The final forging temperature should be controlled at no less than 900°C. Water cool the bar material rapidly within 15 seconds after forging. Heat the water-cooled bar material to 850–900°C, hold it at that temperature for no less than 2 hours after it is fully heated, and then air cool it. The forged and processed billet is reheated to 20–40°C below the phase transformation point, and the holding time is calculated at 1.0–1.3 min / mm. After being taken out of the furnace for forging, the deformation amount should be 30%–50%, and the forging time should be strictly controlled within 1 minute. The final forging temperature should be controlled at no less than 850°C. The billet is then rapidly water-cooled within 15 seconds after forging. The water-cooled billet is then heated to 830–850°C, and after being thoroughly heated, it is held at that temperature for no less than 2 hours, followed by air cooling. The forged and processed billet is reheated to 30-50°C below the phase transformation point, and the holding time is calculated at 0.8-1.3 min / mm. After being taken out of the furnace for forging, the deformation amount should be 40%-60%, and the forging time should be strictly controlled within 1 minute. The final forging temperature should be controlled at no less than 830°C. The billet is then rapidly water-cooled within 15 seconds after forging. The water-cooled billet is then heated to 800-830°C, and after being thoroughly heated, it is held at that temperature for no less than 2 hours before being air-cooled.
3. The method according to claim 1 or 2, characterized in that, The temperature difference between two adjacent static recrystallization heating temperatures is 10–15°C.
4. The method according to claim 1 or 2, characterized in that, The water used for water cooling is flowing water, and the number of forgings cooled at one time should not be too large to ensure that the water temperature does not rise to 50°C during the cooling process.
5. The method according to claim 1 or 2, characterized in that, Heating the TC11 titanium alloy rod material segment to 0-30°C above its phase transformation point includes: The TC11 titanium alloy rod material segment is first preheated to the preheating step, that is, 30-50℃ below the phase transformation point, and the holding time is calculated as 0.8-1.3min / mm. The preheated rod material segment is heated to 0-30℃ above the phase transformation point, and the holding time is calculated as 0.5-1.0 min / mm.
6. The method according to claim 1 or 2, characterized in that, The billet after forging and water cooling is then heated and held at a temperature 0-50°C lower than the final forging temperature after the forging process, and held for at least 2 hours before air cooling.
7. The method according to claim 1, characterized in that, The final forging temperature of the first forging of the bar material segment should be controlled to be lower than the corresponding pre-forging heating temperature and the difference should not exceed 80℃. The final forging temperature of the second forging should be controlled to be lower than the corresponding pre-forging heating temperature and the difference should not exceed 120℃.
8. The method according to claim 2, characterized in that, The final forging temperature of the first forging of the bar material segment should be controlled to be lower than the corresponding pre-forging heating temperature and the difference should not exceed 80℃. The final forging temperature of the second and third forgings should be controlled to be lower than the corresponding pre-forging heating temperature and the difference should not exceed 120℃.
Citation Information
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