A high-efficiency homogenizing forging method for large-size titanium alloy ingot

Abstract

This invention discloses a highly efficient and homogenized forging method for large-size titanium alloy ingots, comprising the following steps: 1. Forging after holding at 150℃~250℃ above the phase transformation point to achieve a height-to-diameter ratio of less than 2.5; 2. Forging after reheating in the furnace; 3. Forging after holding at 50℃~150℃ above the phase transformation point; 4. Forging after holding at 20℃~40℃ below the phase transformation point; 5. Water cooling after holding at 10℃~40℃ above the phase transformation point; 6. Forging after holding at 20℃~40℃ below the phase transformation point. The method of this invention achieves a suitable height-to-diameter ratio through slow upsetting and shaping, suppressing excessive grain growth during deformation and timely releasing stress concentration during deformation to ensure that the ingot does not crack while the grains break down. By chamfering and flattening or elongating, the forging blank is deformed uniformly at multiple angles, avoiding small deformation at the contact point between the forging blank and the anvil, and preventing cracking of the forging blank's sides under tensile stress. This method is suitable for the field of titanium alloy material processing technology.

Description

Technical Field

[0001] This invention belongs to the field of titanium alloy material processing technology, and in particular relates to an efficient and homogenized forging method for large-size titanium alloy ingots. Background Technology

[0002] Titanium alloys, due to their high specific strength, high temperature resistance, corrosion resistance, and weldability, are widely used in aerospace, shipbuilding, weaponry, petroleum, chemical, and medical fields. With the implementation of major projects in aerospace, shipbuilding, and other fields, the performance requirements for materials are constantly increasing, and the specifications of materials are also continuously expanding. For example, the demand for large-format, thick plates and ultra-large titanium alloy bars (diameter greater than 300mm) is constantly growing, which requires the specifications of material billets to continue to increase. However, the larger the billet specifications, the more difficult the material is to process, the worse the forging uniformity, and the more difficult it is to achieve a homogenized microstructure.

[0003] To ensure uniformity, conventional processing requires cutting the ingot into smaller pieces and then performing multiple heats for uniform deformation to guarantee the forgeability and microstructure of the material. However, this method cannot meet the requirements for large forgings. Furthermore, the reduced size of the billet and the increased number of heats increase processing costs and can lead to differences in microstructure and properties between different billets. Therefore, using large-sized ingots for direct forging is more advantageous in reducing costs and improving the microstructure uniformity of the forgings. Currently, the height-to-diameter ratio of large titanium alloy ingots generally exceeds 2.5, while conventional forging requires a height-to-diameter ratio not to exceed 2.5. A larger height-to-diameter ratio can easily cause billet bending or double-bulging during upsetting, and the larger cross-sectional area also increases the deformation dead zone, resulting in uneven microstructure deformation during billet forging. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a highly efficient and homogenized forging method for large-size titanium alloy ingots. This forging method, through slow upsetting and shaping, obtains a forging billet with a suitable aspect ratio for deformation. It also suppresses excessive grain growth during deformation and promptly releases some stress concentrations that occur during deformation, ensuring that the ingot does not crack while the grains break down. By employing chamfering and flattening and chamfering and elongating processes during forging, the forging billet can be deformed uniformly from multiple angles. This avoids minimal or no deformation at the contact point between the forging billet and the anvil, as well as cracking or uneven deformation of the forging billet side under tensile stress. This solves the problems of billet bending or double-bulging during the forging of large-size ingots, and uneven deformation during the forging process.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is: a highly efficient and homogenized forging method for large-size titanium alloy ingots, characterized in that the forging method includes the following steps:

[0006] Step 1: Heat the ingot with a height-to-diameter ratio greater than 2.5 to 150°C to 250°C above the phase transformation point and hold it at that temperature before performing the first forging to obtain a first forging billet with a height-to-diameter ratio less than 2.5; the first forging process includes slow upsetting deformation and shaping during the slow upsetting deformation process.

[0007] Step 2: After the first forging billet obtained in Step 1 is kept warm in the furnace, it is forged a second time to obtain the second forging billet;

[0008] Step 3: Heat the second forging billet obtained in Step 2 to 50°C to 150°C above the phase transformation point and hold it at that temperature before performing a third forging to obtain a third forging billet; the process of the third forging is as follows: repeat the process of chamfering and flattening along the height direction, shaping, upsetting along the height direction, and chamfering and elongating along the length direction twice.

[0009] Step 4: After holding the third forging billet obtained in Step 3 at a temperature of 20℃~40℃ below the phase transformation point, perform a fourth forging to obtain the fourth forging billet;

[0010] Step 5: After holding the fourth forging billet obtained in Step 4 at a temperature 10℃~40℃ above the phase transformation point, water cool it.

[0011] Step 6: After the fourth forging billet in step 5 has been water-cooled, it is kept at 20℃~40℃ below the phase transformation point and then subjected to the fifth forging and shaping to obtain a forging with uniform structure.

[0012] This invention sets the first forging process at a relatively high temperature of 150°C to 250°C above the phase transformation point. Under this temperature condition, the as-cast structure exhibits good fluidity, high plasticity, low deformation resistance, and ease of deformation, especially for large-sized ingots with coarse grain sizes, where the deformed ingots are less prone to cracking. Because the coarse grains are broken to a certain extent after the first forging, the internal structure is improved and the material's plasticity is increased, thus allowing the temperature to gradually decrease in subsequent forging processes. By controlling the temperature to be held at 10°C to 40°C above the phase transformation point followed by water cooling, the aim is to homogenize the microstructure from the initial forging. Water cooling results in a fine lamellar structure, storing a certain amount of distortion energy to ensure dynamic recrystallization during subsequent forging processes, leading to fine equiaxed grains.

[0013] This invention obtains a forging billet with a suitable aspect ratio for deformation through slow upsetting and shaping, which can suppress excessive grain growth during deformation and release some stress concentration during deformation, ensuring that the ingot does not crack while the grains break down. The heat loss during the initial deformation process is replenished by reheating in the furnace, facilitating subsequent upsetting and drawing forging. Then, by controlling the temperature above the phase transformation point to ensure good material fluidity, and combining chamfering and flattening with chamfering and drawing for multi-angle uniform deformation forging, the contact area between the billet and the anvil is reduced, minimizing the deformation dead zone. Furthermore, it improves the uniformity of deformation of the edges and the billet, avoiding minimal or no deformation at the contact point between the billet and the anvil, and preventing cracking or uneven stress on the sides of the billet under tensile stress. Specifically:

[0014] Chamfering and flattening along the height direction can reduce the contact area between the billet and the anvil in the subsequent upsetting process, thus reducing the deformation dead zone; chamfering and elongating along the length direction can avoid the deformation at the corners and the contact surface with the anvil being inconsistent with the core deformation, thus avoiding repeated upsetting and drawing.

[0015] The above-mentioned efficient and homogenized forging method for large-size titanium alloy ingots is characterized in that the slow upsetting deformation in step one has a reduction rate of 30mm / s to 40mm / s and a reduction amount of 15% to 30%; the holding time t1 is calculated by the following formula:

[0016] t1 = η1 × D1;

[0017] Where t1 is the holding time in minutes; D1 is the cross-sectional diameter of the ingot in step one in mm; and η1 is the heating coefficient, ranging from 0.7 to 0.9.

[0018] The above-mentioned efficient and homogenized forging method for large-size titanium alloy ingots is characterized in that, in step two, the second forging involves 2 to 3 upsetting and drawing deformations, and the upsetting and drawing deformation elongation process includes chamfering deformation.

[0019] The above-mentioned efficient and homogenized forging method for large-size titanium alloy ingots is characterized in that, in step three, the reduction amount for chamfering and flattening along the height direction is 10% to 15%, and the reduction rate is 30 mm / s to 40 mm / s; the upsetting ratio for upsetting along the height direction is 1.2 to 1.6; the reduction amount for chamfering and elongating along the length direction is 10% to 20%; and the holding time t2 is calculated by the following formula:

[0020] t2 = η2 × D2;

[0021] Where t2 is the holding time in minutes; D2 is the minimum average thickness of the second forging billet in step three in mm; and η2 is the heating coefficient, ranging from 0.6 to 0.8.

[0022] The above-mentioned efficient and homogenized forging method for large-size titanium alloy ingots is characterized in that, in the fourth forging step, the upsetting and drawing deformation is performed at least twice, and the cumulative deformation of each upsetting and drawing deformation is at least 85%; the holding time t3 is calculated by the following formula:

[0023] t3 = η3 × D3;

[0024] Where t3 is the holding time in minutes; D3 is the minimum average thickness of the third forging billet in step four in mm; and η3 is the heating coefficient, ranging from 0.6 to 0.8.

[0025] This invention ensures that the forging billet does not crack while guaranteeing a sufficiently large deformation amount in a single upsetting and drawing process by setting the cumulative deformation amount in a single upsetting and drawing process to not less than 85%.

[0026] The above-mentioned efficient and homogenized forging method for large-size titanium alloy ingots is characterized in that the holding time t2 in step five is calculated by the following formula:

[0027] t4 = η4 × D4;

[0028] Where t4 is the holding time in minutes; D4 is the minimum average thickness of the fourth forging billet in step five in mm; and η4 is the heating coefficient, ranging from 0.6 to 0.8.

[0029] The above-mentioned efficient and homogenized forging method for large-size titanium alloy ingots is characterized in that, in the fifth forging in step six, the upsetting and drawing deformation is not less than 2 times, and the cumulative deformation of each upsetting and drawing deformation is not less than 80%.

[0030] This invention ensures that the forging billet is fully deformed by setting the number of upsetting and drawing deformations and the cumulative deformation amount of a single upsetting and drawing deformation to be no less than 80%.

[0031] The above-mentioned efficient and homogenized forging method for large-size titanium alloy ingots is characterized in that the holding time t5 in step six is ​​calculated by the following formula:

[0032] t5 = η5 × D5;

[0033] Where t5 is the holding time in minutes; D5 is the minimum average thickness of the fourth forging billet in step six in mm; and η5 is the heating coefficient, ranging from 0.6 to 0.8.

[0034] Compared with the prior art, the present invention has the following advantages:

[0035] 1. This invention obtains a forging billet with a suitable aspect ratio for deformation through slow upsetting, and can suppress excessive grain growth during deformation and release some stress concentration during deformation in a timely manner. It controls the deformation amount within a certain range to ensure grain breakage without cracking. The slow upsetting process is used to shape the billet to ensure its straightness, which facilitates further upsetting deformation until the aspect ratio of the billet is suitable for forging. Then, by using chamfering and flattening and chamfering and elongating processes during forging, the forging billet is deformed uniformly from multiple angles. This avoids the forging billet and anvil contact area from deforming little or no deformation during the deformation process, as well as cracking or uneven deformation of the forging billet side under tensile stress. It also avoids bending or double-bulging phenomena in large-sized ingots during subsequent forging.

[0036] 2. This invention avoids the reduction in billet size and the differences in microstructure and properties between billets caused by the separate forging process used in the prior art by forging large-size ingots as a whole.

[0037] 3. This invention, by forging below the phase transformation point and then holding it above the phase transformation point before water cooling, can homogenize the two-phase region structure in the β region after forging, providing a uniformly structured forging blank for subsequent forging. At the same time, the acicular martensite generated after water cooling can be broken during the forging process, producing fine equiaxed grains, thereby optimizing the performance while homogenizing the structure of the forging blank.

[0038] 4. The present invention determines the holding time based on the cross-sectional size of the ingot or forging billet at each stage. The heat progress during holding is 1 mm per minute. Therefore, the basic heating time is 0.5 times the cross-sectional size. Then, the heating coefficient is increased based on the billet condition and cross-sectional size to ensure that the ingot or forging billet at each stage is fully heated.

[0039] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0040] Figure 1 This is a photograph of the forging process of the chamfering and flattening process of this invention.

[0041] Figure 2 This is a photograph of the forging process of the upsetting process after beveling and flattening according to the present invention.

[0042] Figure 3 This is a microstructure diagram of the surface region of the bar obtained in Example 1 of the present invention.

[0043] Figure 4 This is a microstructure diagram of the central part of the bar obtained in Example 1 of the present invention.

[0044] Figure 5 This is a microstructure diagram of the surface area of ​​the plate obtained in Example 2 of the present invention.

[0045] Figure 6 This is a microstructure diagram of the central part of the plate obtained in Example 2 of the present invention.

[0046] Figure 7 This is a microstructure diagram of the surface region of the bar obtained in Example 3 of the present invention.

[0047] Figure 8 This is a microstructure diagram of the central part of the bar obtained in Example 3 of the present invention. Detailed Implementation

[0048] Example 1

[0049] The TA16 ingot in this embodiment, after peeling and cutting the riser, has dimensions of Φ248mm×875mm and a height-to-diameter ratio of 3.5. The forging method of this ingot includes the following steps:

[0050] Step 1: After heating the ingot to 1160℃ and holding it for 180 minutes, the first forging is carried out. First, the ingot is upset at a reduction rate of 40mm / s and a reduction of 15% along the height direction. Then, the ingot is upset at a reduction rate of 30mm / s and a reduction of 30% along the height direction. The ingot is then shaped along the axis to make it straight. Then, the ingot is upset at a reduction rate of 40mm / s and a reduction of 25% along the height direction to obtain an ingot with a diameter of 354mm. The ingot is then drawn to obtain a square billet (first forging billet) with dimensions of 265mm×265mm and a height-to-diameter ratio of 2.26.

[0051] Step 2: The first forging billet obtained in Step 1 is reheated to 1160℃ and held for 80 minutes, then subjected to three upsetting and drawing deformations. After air cooling, a second forging billet with dimensions of 265mm×265mm×600mm is obtained. The drawing process includes chamfering deformation. The cumulative deformation of the single upsetting and drawing deformation is not less than 85%, and the final forging temperature of the three upsetting and drawing deformations is not less than 800℃.

[0052] Step 3: After heating the second forging billet obtained in Step 2 to 1060℃ and holding it for 160 minutes, perform the third forging: flatten and chamfer along the height direction with a reduction of 10% and a reduction rate of 40mm / s, shape along the axis direction, upset with an upsetting ratio of 1.6 along the height direction, and chamfer and elongate along the length direction with a feed amount of 1.0 and a reduction of 10%, then shape it into a square billet; then flatten and chamfer along the height direction with a reduction of 10%, shape, upset with an upsetting ratio of 1.3 along the height direction, and chamfer and elongate along the length direction with a feed amount of 0.5 and a reduction of 10%, and then shape it into a square billet with dimensions of 265mm×265mm (the third forging billet); the feed amount is the ratio of the anvil feed length to the forging billet height;

[0053] Step 4: After holding the third forging billet obtained in Step 3 at 890℃ for 160 minutes, perform three upsetting and drawing deformations. The cumulative deformation of each upsetting and drawing deformation shall not be less than 85%, resulting in a square billet (fourth forging billet) with dimensions of 265mm×265mm.

[0054] Step 5: After holding the fourth forging billet obtained in Step 4 at 950℃ for 160 minutes, water cool it.

[0055] Step 6: After the fourth forging billet in step 5 is water-cooled, it is held at 890℃ for 160 minutes and then subjected to two upsetting and drawing deformations. The cumulative deformation of each upsetting and drawing is not less than 80%. After shaping, a bar with a diameter of 180mm is obtained.

[0056] Microstructural analysis was performed on the surface and central portion of the rod obtained in this embodiment, such as... Figure 3 and Figure 4 As shown, the microstructure of the rod is uniformly distributed in different regions, consisting of equiaxed α phase and partially transformed β phase, and the equiaxed α phase grains are uniform in size in different regions.

[0057] Example 2

[0058] The TC4 ingot of this embodiment, after peeling and cutting the riser, has dimensions of Φ500mm×1500mm and a height-to-diameter ratio of 3.0. The forging method of this ingot includes the following steps:

[0059] Step 1: After heating the ingot to 1120℃ and holding it for 450 minutes, the first forging is carried out. First, the ingot is upset at a reduction rate of 30mm / s and a reduction of 20% along the height direction. Then, it is shaped along the height direction. Next, the ingot is upset at a reduction rate of 40mm / s and a reduction of 15% along the height direction. Then, the ingot is upset at a reduction rate of 30mm / s and a reduction of 15% along the height direction. After drawing, a square billet with dimensions of 550mm×550mm and a height-to-diameter ratio of 2.5 (first forging billet) is obtained.

[0060] Step 2: The first forging billet obtained in Step 1 is reheated to 1120℃ and held for 280 minutes, then subjected to three upsetting and drawing deformations. After air cooling, a square billet (second forging billet) with dimensions of 550mm×550mm is obtained. The drawing process includes chamfering deformation. The cumulative deformation of the single upsetting and drawing deformation is not less than 85%, and the final forging temperature of the three upsetting and drawing deformations is not less than 800℃.

[0061] Step 3: After heating the second forging billet obtained in Step 2 to 1030℃ and holding it for 440 minutes, perform the third forging: flatten and chamfer along the height direction with a reduction of 15% and a reduction rate of 30mm / s, shape along the axis direction, upset with an upsetting ratio of 1.2 along the height direction, and chamfer and elongate along the length direction with a feed amount of 0.5 and a reduction of 20%, then shape it into a square billet; then flatten and chamfer along the height direction with a reduction of 10%, shape, upset with an upsetting ratio of 1.7 along the height direction, and chamfer and elongate along the length direction with a feed amount of 1.0 and a reduction of 20%, and then shape it into a square billet with dimensions of 550mm×550mm (the third forging billet); the feed amount is the ratio of the anvil feed length to the forging billet height;

[0062] Step 4: After holding the third forging billet obtained in Step 3 at 930℃ for 440 minutes, perform three upsetting and drawing deformations. The cumulative deformation of each upsetting and drawing deformation shall not be less than 85%, resulting in a square billet (fourth forging billet) with dimensions of 550mm×550mm.

[0063] Step 5: After holding the fourth forging billet obtained in Step 4 at 980℃ for 440 minutes, water cool it.

[0064] Step 6: After the fourth forging billet in step 5 is water-cooled, it is held at 930℃ for 440 minutes and then subjected to two upsetting and drawing deformations. The cumulative deformation of each upsetting and drawing is not less than 80%. After shaping, a plate with dimensions of 200mm×600mm×800mm is obtained.

[0065] Microstructural analysis was performed on the surface and central portion of the plate obtained in this embodiment, such as... Figure 5 and Figure 6 As shown, the α-grain size on the surface of the plate is elongated, but the overall structure is relatively uniform; the deformation at the center of the plate is more uniform, dynamic recrystallization has occurred, and the grain size is small and uniform.

[0066] Example 3

[0067] The TC4 ingot of this embodiment, after peeling and cutting the riser, has dimensions of Φ320mm×1100mm, a height-to-diameter ratio of 3.2, and an alloy phase transformation point of 980℃. The forging method of this ingot includes the following steps:

[0068] Step 1: After heating the ingot to 1150℃ and holding it for 220 minutes, the first forging is carried out. First, the ingot is upset at a reduction rate of 30mm / s and a reduction of 15% along the height direction. Then, the ingot is upset at a reduction rate of 30mm / s and a reduction of 15% along the height direction. The ingot is shaped along the axis to make it straight. Then, the ingot is upset at a reduction rate of 40mm / s and a reduction of 20% along the height direction to obtain the first forging ingot with a diameter of 420mm and a height-to-diameter ratio of 1.5.

[0069] Step 2: The first forging billet obtained in Step 1 is reheated to 1150℃ and held for 120 minutes, then subjected to two upsetting and drawing deformations. After air cooling, a second forging billet with dimensions of 340mm×340mm×765mm is obtained. During the drawing process, chamfering deformation and drawing are performed. The cumulative deformation of a single upsetting and drawing deformation is not less than 85%, and the final forging temperature of the upsetting and drawing deformation is not less than 800℃.

[0070] Step 3: After heating the second forging billet obtained in Step 2 to 1050℃ and holding it for 210 minutes, perform the third forging: chamfer and flatten it along the height direction with a chamfering reduction of 15% and a reduction rate of 40mm / s, shape it along the axis direction, upset it along the height direction with an upsetting ratio of 1.5, and chamfer and elongate it along the length direction with a feed amount of 0.8 and a reduction of 15%, and then shape it into a square billet; then chamfer and flatten it along the height direction with a reduction of 10%, shape it, upset it along the height direction with an upsetting ratio of 1.3, and chamfer and elongate it along the length direction with a feed amount of 0.5 and a reduction of 15%, and then shape it into a square billet with dimensions of 340mm×340mm (the third forging billet);

[0071] Step 4: After holding the third forging billet obtained in Step 3 at 950℃ for 200 minutes, perform three upsetting and drawing deformations. The cumulative deformation of each upsetting and drawing deformation shall not be less than 85%, resulting in a square billet (fourth forging billet) with dimensions of 340mm×340mm.

[0072] Step 5: After holding the fourth forging billet obtained in Step 4 at 990℃ for 200 minutes, water cool it.

[0073] Step 6: After the fourth forging billet in step 5 is water-cooled, it is held at 950℃ for 270 minutes and then subjected to two upsetting and drawing deformations. The cumulative deformation of each upsetting and drawing is not less than 80%. After shaping, a large-diameter bar with a diameter of 350mm is obtained.

[0074] Microstructural analysis was performed on the surface and central portion of the rod obtained in this embodiment, such as... Figure 7 and Figure 8 As shown, the microstructure of the rod is uniformly distributed in different regions, consisting of equiaxed α phase and partially transformed β phase, and the size of the equiaxed α phase grains is relatively uniform in different regions.

[0075] The above description is merely a preferred embodiment of the present invention and does not constitute any limitation on the present invention. Any simple modifications, alterations, or equivalent structural transformations made to the above embodiments based on the technical essence of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A highly efficient and homogenized forging method for large-size titanium alloy ingots, characterized in that, The forging method includes the following steps: Step 1: Heating an ingot with a height-to-diameter ratio greater than 2.5 to 150°C~250°C above the phase transformation point and holding it therefore, the first forging is performed to obtain a first forging billet with a height-to-diameter ratio less than 2.

5. The first forging process includes slow upsetting deformation, and shaping is performed during the slow upsetting deformation process. The downsetting rate of the slow upsetting deformation is 30mm / s~40mm / s, and the downsetting amount is 15%~30%. Step 2: After the first forging billet obtained in Step 1 is kept warm in the furnace, it is forged again to obtain the second forging billet; the second forging is to perform 2 to 3 upsetting and drawing deformations, and the upsetting and drawing deformation process includes chamfering deformation; Step 3: Heat the second forging billet obtained in Step 2 to 50℃~150℃ above the phase transformation point and hold for a third forging to obtain the third forging billet. The third forging process is as follows: repeat the processes of chamfering and flattening along the height direction, shaping, upsetting along the height direction, and chamfering and elongating along the length direction twice. The reduction amount of chamfering and flattening along the height direction is 10%~15%, and the reduction rate is 30mm / s~40mm / s. The upsetting ratio of upsetting along the height direction is 1.2~1.

6. The reduction amount of chamfering and elongating along the length direction is 10%~20%. Step 4: After holding the third forging billet obtained in Step 3 at a temperature of 20℃~40℃ below the phase transformation point, perform a fourth forging to obtain a fourth forging billet; the cumulative deformation of a single upsetting deformation in the fourth forging shall not be less than 85%; Step 5: After holding the fourth forging billet obtained in Step 4 at a temperature 10℃~40℃ above the phase transformation point, water cool it. Step 6: After the fourth forging billet in step 5 has been water-cooled, it is kept at 20℃~40℃ below the phase transformation point and then subjected to the fifth forging and shaping to obtain a forging with uniform structure.

2. The efficient and homogenized forging method for large-size titanium alloy ingots according to claim 1, characterized in that, The heat preservation time t1 mentioned in step one is calculated by the following formula: ； Where t1 is the holding time in minutes; D1 is the cross-sectional diameter of the ingot in step one in mm; and η1 is the heating coefficient, ranging from 0.7 to 0.

9.

3. The efficient and homogenized forging method for large-size titanium alloy ingots according to claim 1, characterized in that, The heat preservation time t2 mentioned in step three is calculated by the following formula: ； Where t2 is the holding time in minutes; D2 is the minimum average thickness of the second forging billet in step three in mm; and η2 is the heating coefficient, ranging from 0.6 to 0.

8.

4. The efficient and homogenized forging method for large-size titanium alloy ingots according to claim 1, characterized in that, In step four, the upsetting and drawing deformation in the fourth forging process shall not be less than twice; the holding time t3 shall be calculated by the following formula: ； Where t3 is the holding time in minutes; D3 is the minimum average thickness of the third forging billet in step four in mm; and η3 is the heating coefficient, ranging from 0.6 to 0.

8.

5. The efficient and homogenized forging method for large-size titanium alloy ingots according to claim 1, characterized in that, The heat preservation time t4 mentioned in step five is calculated by the following formula: ； Where t4 is the holding time in minutes; D4 is the minimum average thickness of the fourth forging billet in step five in mm; and η4 is the heating coefficient, ranging from 0.6 to 0.

8.

6. The efficient and homogenized forging method for large-size titanium alloy ingots according to claim 1, characterized in that, In step six, the fifth forging process involves upsetting and drawing deformation at least twice, and the cumulative deformation of each upsetting and drawing deformation is at least 80%.

7. The efficient and homogenized forging method for large-size titanium alloy ingots according to claim 1, characterized in that, The heat preservation time t5 described in step six is ​​calculated using the following formula: ； Where t5 is the holding time in minutes; D5 is the minimum average thickness of the fourth forging billet in step six in mm; and η5 is the heating coefficient, ranging from 0.6 to 0.8.

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