A method for forging a large-size Ti80 titanium alloy forging blank
By optimizing the forging process and adopting a method of single-fire forging, multiple re-forging, and water cooling, the problems of uneven microstructure and poor forging penetration of large-size Ti80 titanium alloy forging billets were solved, thereby improving the yield and reducing costs.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- 西部超导材料科技股份有限公司
- Filing Date
- 2023-10-26
- Publication Date
- 2026-06-16
AI Technical Summary
Existing technologies for preparing large-size Ti80 titanium alloy forging billets suffer from problems such as multiple forging processes, uneven material structure, poor forging penetration, and low yield, leading to high material costs.
The forging method employs a single-fire forging process, followed by 1-3 fires of single-phase zone forging, 2-4 fires of two-phase zone forging, and 1-2 fires of water cooling. It combines different deformation and cooling methods, including upsetting, anvil shaping, and anvil drawing, to control the forging ratio and heating temperature, ensuring uniform microstructure and forging penetration.
By reducing the number of forging passes, the microstructure uniformity and forging penetration of large-size Ti80 titanium alloy forging billets were improved, increasing the yield and reducing material costs.
Smart Images
Figure CN117245045B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of non-ferrous metal processing, and specifically relates to a forging method for large-size Ti80 titanium alloy forging billets. Background Technology
[0002] Ti80 titanium alloy is a corrosion-resistant, weldable near-α type titanium alloy independently developed in my country. It possesses high strength, high impact toughness, and good low-cycle fatigue properties, and is widely used in components such as valves, marine pipelines, flanges, and pressure hulls in ships and marine engineering. As a primary titanium alloy material for ships and marine engineering, it has undergone comprehensive application research and evaluation, demonstrating promising application prospects.
[0003] Currently, the most widely used Ti80 alloy forging billets generally weigh less than 2 tons. The engineering preparation technology for large-sized Ti80 titanium alloy forging billets with a finished product weight exceeding 4 tons is not yet mature. The main problems are heavy billet weight, poor forging penetration, and uneven microstructure in different parts due to multiple upsetting and drawing processes.
[0004] Chinese patent CN111906225B discloses a forging method for ultra-large Ti80 titanium alloy forging billets, including: S1, initial forging: performing a single-fire initial forging on a Ti80 ingot, wherein the initial forging method is upsetting, and air-cooling the forged billet; S2, intermediate forging: performing multiple-fire forging on the billet obtained after initial forging; S3, finished product forging: drawing the intermediate-forged billet into shape at a temperature below the phase transformation point, and air-cooling the forged billet to finally obtain a Ti80 titanium alloy forging billet that meets the specifications. However, this application still has certain limitations: the multiple forging fires in this application can easily lead to uneven material structure, poor forging penetration in the core of the material, low yield, and increased material cost. Summary of the Invention
[0005] The purpose of this invention is to provide a forging method for large-size Ti80 titanium alloy forging billets. This method can reduce the number of forging passes, fully refine and homogenize the material microstructure, improve the forgeability of the material core, increase the yield of the material, and reduce material costs.
[0006] To achieve the above objectives, the present invention adopts the following technical solution:
[0007] A forging method for large-size Ti80 titanium alloy forging billets includes the following steps:
[0008] S1, billet forging: The ingot is forged in one firing. The billet forging method is upsetting + cross anvil shaping. The cooling method after forging is air cooling.
[0009] S2, intermediate forging:
[0010] The billet after S1 forging is subjected to 1 to 3 heats of first intermediate forging in the single phase zone. The forging process adopts the method of flattening square + horizontal anvil drawing. The billet is finally flat square cross section. After forging, the billet is chamfered and cooled by air cooling to obtain the billet after first intermediate forging.
[0011] The billet after the first intermediate forging is subjected to 2 to 4 heats of second intermediate forging in the two-phase region. The forging process is carried out by square upsetting, and the billet is finally square in cross section. The cooling method after forging is air cooling, and the billet after the second intermediate forging is obtained.
[0012] The billet after the second intermediate forging is subjected to 1 to 2 third intermediate forgings in the single-phase zone. The forging process is to press the square and draw it with a cross anvil. The billet is finally square in cross section. Water cooling is used after forging to obtain the billet after the third intermediate forging.
[0013] S3, Finished product forging: The forging billet that has been forged in S2 is heated at 30℃~60℃ below the phase transformation point. The finished product forging method is drawing, and the cooling method after forging is air cooling, which yields a large-size Ti80 titanium alloy forging billet.
[0014] Preferably, in step S1, the forging heating temperature for the single-fire forging is selected as 1100℃~1200℃. After reaching the temperature, the forging is held for 7~15 hours before being taken out of the furnace. The ingot is then subjected to a first upsetting deformation using a flat anvil with a width of 1000mm. The upsetting forging ratio is controlled between 1.7 and 2.2. After upsetting, the billet is subjected to cross-anvil shaping and chamfering.
[0015] Preferably, in S2, the heating temperature of each forging of the first intermediate forging is selected to be 20°C to 120°C above the phase transformation point. After the material is taken out of the furnace, it is upsetting and drawing on the cross anvil in sequence, and the forging ratio of each forging is controlled between 1.5 and 2.3.
[0016] Preferably, in S2, the heating temperature of each forging of the second intermediate forging is selected to be 30°C to 60°C below the phase transformation point. After the material is taken out of the furnace, it is upsetting and drawing in sequence, and the forging ratio of each forging is controlled between 1.6 and 2.2.
[0017] Preferably, in S2, the heating temperature of each forging in the third intermediate forging is selected to be 30°C to 70°C above the phase transformation point. After the material is taken out of the furnace, it is upsetting and cross-cutting elongation are performed in sequence, and the forging ratio of each forging is controlled between 1.2 and 2.3.
[0018] Preferably, in step S3, the forging ratio per firing during drawing is controlled between 1.0 and 1.4.
[0019] The beneficial effects of this invention are as follows: By using a 1000mm wide flat anvil for billet forging, the invention ensures the deformation coordination and uniformity of the ingot, avoiding uneven deformation during the billet forging process; the use of a transverse anvil for drawing in the single-phase region ensures the forging penetration and deformation coordination of the core during billet drawing; furthermore, performing 1-2 forging passes above the phase transformation point ensures a uniform intermediate billet structure after recrystallization; and water cooling after forging accelerates the cooling rate of the billet, avoiding uneven microstructure caused by large differences in cooling rates in different parts of the billet. Ultimately, a large-size Ti80 titanium alloy forging billet with uniform high and low magnification microstructure is obtained, reducing the number of forging passes while ensuring billet microstructure uniformity and effectively lowering forging costs. Attached Figure Description
[0020] Figure 1 This is a schematic diagram of the cross-anvil elongation / cross-anvil shaping of a large-size Ti80 forging billet;
[0021] Figure 2 This is a picture of a large-size Ti80 titanium alloy forging billet;
[0022] Figure 3 This is a low-magnification microstructure image of a large-size forging billet with H=250mm prepared in Example 1 of the present invention;
[0023] Figure 4 This is a microstructure image of a large-sized forging billet with H=250mm prepared in Example 1 of this invention;
[0024] Figure 5 This is a low-magnification microstructure image of the large-size forging billet with H=270mm prepared in Example 2 of the present invention;
[0025] Figure 6 This is a microstructure diagram of a large-sized forging billet with H=270mm prepared in Example 2 of the present invention.
[0026] Figure 7 This is a flowchart of the method of the present invention. Detailed Implementation
[0027] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings.
[0028] like Figure 7 As shown, a forging method for a large-size Ti80 titanium alloy forging billet includes the following steps:
[0029] S1, forging in rough blank:
[0030] The ingot is subjected to a single-fire forging process, which involves upsetting followed by cross-anvil shaping. After forging, air cooling is used for cooling.
[0031] The forging heating temperature is selected as 1100℃~1200℃. After reaching the temperature, the temperature is held for 7~15 hours before being taken out of the furnace. The ingot is then subjected to one upsetting deformation using a flat anvil with a width of 1000mm. The upsetting forging ratio is controlled between 1.7 and 2.2. After upsetting, the billet is shaped by a horizontal anvil and chamfered to avoid the appearance of sharp edges and corners, so as to effectively reduce the deformation dead zone of the billet.
[0032] S2, intermediate forging:
[0033] The billet after S1 forging is subjected to 1-3 heats of first intermediate forging in the single-phase region to further break down the coarse as-cast grains. The forging process uses a flattening square + cross-anvil elongation method, resulting in a flat square cross section for the final billet, which effectively improves the forgeability of the billet core. After forging, the billet is chamfered and cooled by air to obtain the billet after the first intermediate forging.
[0034] The heating temperature for each forging of the first intermediate forging is selected to be 20℃ to 120℃ above the phase transformation point. The heating temperature is gradually reduced with each forging. After the material is taken out of the furnace, it is upsetting and cross-cutting elongation are carried out in sequence. The forging ratio of each forging is controlled between 1.5 and 2.3.
[0035] The billet after the first intermediate forging is subjected to a second intermediate forging in the two-phase region for 2 to 4 passes to further refine the grains. The forging process uses square upsetting, and the billet finally has a square cross-section. Air cooling is used after forging to obtain the billet after the second intermediate forging.
[0036] The heating temperature for each forging of the second intermediate forging is selected to be 30℃ to 60℃ below the phase transformation point. The heating temperature is gradually reduced with each forging. Before each forging, the end of the billet is wrapped with asbestos, which helps to increase the final forging temperature and avoid cracks caused by the decrease in billet temperature. After the material is taken out of the furnace, it is upsetting and drawing in sequence. The forging ratio of each forging is controlled between 1.6 and 2.2.
[0037] The billet after the second intermediate forging is subjected to 1 to 2 third intermediate forgings in the single-phase region to further homogenize the billet's microstructure. The forging process uses a combination of pressing into a square shape and drawing with a transverse anvil, resulting in a square cross-section for the billet. Water cooling is used after forging to obtain the billet after the third intermediate forging.
[0038] The heating temperature for each of the third intermediate forging processes is selected to be 30℃ to 70℃ above the phase transformation point. After the material is taken out of the furnace, it is upsetting and drawing on the cross anvil in sequence. The forging ratio for each forging process is controlled between 1.2 and 2.3.
[0039] Water cooling can accelerate the cooling rate of the billet and avoid uneven microstructure caused by large differences in cooling rates in different parts of the billet.
[0040] S3, Finished product forging:
[0041] The forging billet, which has undergone intermediate forging in S2, is heated at 30℃ to 60℃ below the phase transformation point. The finished product is forged by drawing. During drawing, the forging ratio per heat is controlled between 1.0 and 1.4. After forging, air cooling is used to obtain the large-size Ti80 titanium alloy forging billet.
[0042] The present invention will be further described in detail through the following embodiments.
[0043] Example 1
[0044] S1, forging in rough blank:
[0045] The ingot, with a specification of Φ920mm and a weight of 7T, is used. The initial forging is completed by one-fire upsetting forging. The heating temperature for the initial forging of the ingot is selected as 1200℃. After reaching the temperature, it is held at the temperature for 10 hours before being taken out of the furnace. The ingot is then subjected to one upsetting deformation using a flat anvil with a width of 1000mm. The upsetting forging ratio is 2.0. After deformation, the ingot is shaped by the cross anvil and chamfered. The cooling method after forging is air cooling.
[0046] S2, intermediate forging:
[0047] The billet after S1 forging is forged three times in the single-phase zone. The heating temperature for each forging is selected to be 20℃ to 120℃ above the phase transformation point, and the heating temperature is gradually reduced in each forging. After the material is taken out of the furnace, it is upsetting and cross-cutting drawing are performed in sequence. The forging ratio for each forging is 1.8. The cooling method after forging is air cooling, and the billet after the first intermediate forging is obtained.
[0048] The billet after the first intermediate forging is forged three times in the two-phase region. The heating temperature for each forging is selected to be 20℃ to 50℃ below the phase transformation point, and the heating temperature is gradually reduced for each forging. Before each forging, the end of the billet is wrapped with asbestos. After the material is taken out of the furnace, it is upsetting and drawing in sequence. The forging ratio for each forging is 1.7. The cooling method after forging is air cooling, to obtain the billet after the second intermediate forging.
[0049] The billet after the second intermediate forging is forged once in the single-phase zone. The heating temperature is selected to be 40°C above the phase transformation point. After the material is taken out of the furnace, it is upsetting and cross-cutting elongation in sequence. The forging ratio per forging is 1.8. Water cooling is used after forging to obtain the billet after the third intermediate forging.
[0050] S3, Finished product forging:
[0051] The billet after S2 intermediate forging is heated at 50°C below the phase transformation point and drawn into shape. The forging ratio per forging is 1.2, and the finished size H = 250mm is forged. After forging, air cooling is used to obtain a large-size Ti80 titanium alloy forging billet.
[0052] Example 2
[0053] S1, forging in rough blank:
[0054] The ingot, with a specification of Φ920mm and a weight of 7T, was used. The initial forging was completed by a single upsetting process. The heating temperature for the initial forging of the ingot was selected as 1150℃. After reaching the temperature, it was held at that temperature for 15 hours before being taken out of the furnace. The ingot was then subjected to a single upsetting deformation using a flat anvil with a width of 1000mm. The upsetting ratio was 2.2. After the deformation was completed, the ingot was shaped by the cross anvil and chamfered. The cooling method after forging was air cooling.
[0055] S2, intermediate forging:
[0056] The billet after the initial forging in step 1 is forged twice in the single-phase zone. The heating temperature for each forging is selected to be 20℃ to 120℃ above the phase transformation point, and the heating temperature is gradually reduced in each forging. After the material is taken out of the furnace, it is upsetting and cross-cutting drawing are performed in sequence. The forging ratio for each forging is 2.0. The cooling method after forging is air cooling, and the billet after the first intermediate forging is obtained.
[0057] The billet after the first intermediate forging is forged three times in the two-phase region. The heating temperature for each forging is selected to be 20℃ to 50℃ below the phase transformation point, and the heating temperature is gradually reduced for each forging. Before each forging, the end of the billet is wrapped with asbestos. After the material is taken out of the furnace, it is upsetting and drawing in sequence. The forging ratio for each forging is 1.6. The cooling method after forging is air cooling, to obtain the billet after the second intermediate forging.
[0058] The billet after the second intermediate forging is forged twice in the single-phase zone. The heating temperature is selected to be 30℃~70℃ above the phase transformation point. After the material is taken out of the furnace, it is upsetting and cross-cutting drawing are performed in sequence. The forging ratio of each forging is 2.0. Water cooling is used after forging to obtain the billet after the third intermediate forging.
[0059] S3, Finished product forging:
[0060] The billet after S2 intermediate forging is heated at 40°C below the phase transformation point and drawn into shape. The forging ratio per forging is 1.3, and the finished size H = 270mm is forged. After forging, air cooling is used to obtain a large-size Ti80 titanium alloy forging billet.
[0061] Figure 1 This is a schematic diagram of the cross-anvil drawing / shaping of a large-size Ti80 forging billet. Figure 2 This is a photograph of a large-sized Ti80 titanium alloy forging billet. Figure 3This is a low-magnification microstructure image of a large-sized forging billet with a finished product specification of H=250mm, produced by this forging process. It can be seen that the low-magnification image is uniformly blurred. Figure 4 The images show the microstructure at different locations on the forging billet. The microstructure is uniform from the edge to the center of the billet, and the content of primary α phase is similar in different locations.
[0062] The mechanical properties of the large-sized forging blanks were tested after heat treatment, and the results are shown in Table 1.
[0063] Table 1. List of mechanical properties of forging billets with H=250mm specification
[0064] Rm / Mpa Rp0.2 / Mpa A / ％ Z / ％ Kv2 / J 904 800 17.5 50 57.2 898 800 18.0 52 58.3
[0065] Figure 5 This is a low-magnification microstructure image of a large-sized forging billet with a finished product specification of H=270mm, which was forged using this process. It can be seen that the low-magnification image is uniformly blurred. Figure 6 The images show the microstructure at different locations of the forging billet. The microstructure is uniform from the edge to the center of the billet, and the content of primary α phase is similar in different locations, indicating that the forging billet underwent sufficient and uniform deformation during the forging process.
[0066] The mechanical properties of the large-sized forging blanks were tested after heat treatment, and the results are shown in Table 2.
[0067] Table 2 lists the mechanical properties of forging billets with H=270mm specification.
[0068] Rm / Mpa Rp0.2 / Mpa A / ％ Z / ％ Kv2 / J 884 790 17.0 51 58.8 880 785 20.0 48 59.9
Claims
1. A forging method for large-size Ti80 titanium alloy forging billets, characterized in that, Includes the following steps: S1, billet forging: The ingot is forged in one firing. The billet forging method is upsetting + cross anvil shaping. The cooling method after forging is air cooling. In S1, the forging heating temperature for the single-fire forging is selected as 1100℃~1200℃. After reaching the temperature, the forging is held for 7~15 hours before being taken out of the furnace. The ingot is then subjected to one upsetting deformation using a flat anvil with a width of 1000mm. The upsetting forging ratio is controlled between 1.7 and 2.
2. After upsetting, the billet is subjected to cross anvil shaping and chamfering. S2, intermediate forging: The billet after S1 forging is subjected to 1 to 3 heats of first intermediate forging in the single phase zone. The forging process adopts the method of flattening square + horizontal anvil drawing. The billet is finally flat square cross section. After forging, the billet is chamfered and cooled by air cooling to obtain the billet after first intermediate forging. The billet after the first intermediate forging is subjected to 2 to 4 heats of second intermediate forging in the two-phase region. The forging process is carried out by square upsetting, and the billet is finally square in cross section. The cooling method after forging is air cooling, and the billet after the second intermediate forging is obtained. The billet after the second intermediate forging is subjected to 1 to 2 third intermediate forgings in the single-phase zone. The forging process is to press the square and draw it with a cross anvil. The billet is finally square in cross section. Water cooling is used after forging to obtain the billet after the third intermediate forging. S3, Finished product forging: The forging billet that has been forged in S2 is heated at 30℃~60℃ below the phase transformation point. The finished product forging method is drawing, and the cooling method after forging is air cooling, which yields a large-size Ti80 titanium alloy forging billet.
2. The forging method for large-size Ti80 titanium alloy forgings according to claim 1, characterized in that, In S2, the heating temperature for each forging of the first intermediate forging is selected to be 20°C to 120°C above the phase transformation point. After the material is taken out of the furnace, it is upsetting and drawing on the cross anvil in sequence. The forging ratio for each forging is controlled between 1.5 and 2.
3.
3. The forging method for large-size Ti80 titanium alloy forgings according to claim 1, characterized in that, In S2, the heating temperature for each heat of the second intermediate forging is selected to be 30°C to 60°C below the phase transformation point. After the material is taken out of the furnace, it is upsetting and drawing in sequence, and the forging ratio for each heat is controlled between 1.6 and 2.
2.
4. The forging method for large-size Ti80 titanium alloy forgings according to claim 1, characterized in that, In S2, the heating temperature of each forging in the third intermediate forging is selected to be 30°C to 70°C above the phase transformation point. After the material is taken out of the furnace, it is upsetting and drawing on the cross anvil in sequence. The forging ratio of each forging is controlled between 1.2 and 2.
3.
5. The forging method for large-size Ti80 titanium alloy forgings according to claim 1, characterized in that, In S3, the forging ratio per firing during drawing is controlled between 1.0 and 1.4.