Over-9-ton extra-large-specification high-impact-toughness Ti80 titanium alloy forging stock and manufacturing method thereof

Abstract

The invention discloses a high-impact-toughness Ti80 titanium alloy forging stock with the extra-large specification of more than 9 tons and a manufacturing method. The manufacturing method comprises the following steps: S1) adopting a Ti80 titanium alloy cast ingot with the diameter of 960-1060 mm and the weight of 9-17 tons; (S2) cogging and forging are conducted, the cast ingot is subjected to upsetting and drawing for 2-5 heating numbers in a beta-phase region, and the upsetting and drawing deformation of each heating number is 30-55%; (S3) intermediate forging is conducted, specifically, the blank is subjected to 3-4 heating number upsetting and drawing in a beta-phase region, the upsetting and drawing deformation of each heating number is 30-55%, and air cooling is conducted after upsetting and drawing; and (S4) finished product forging is conducted, 3-5 heating number drawing is conducted at the temperature 30-60 DEG C below the phase transformation point, the deformation of each heating number is 10-30%, and the total deformation is larger than or equal to 50%. The thickness of the obtained forging stock is 200-500 mm, the width is 1000-2500 mm, the length is 2000-4000 mm, and after the forging stock is annealed, the tensile strength of each position is larger than or equal to 840 MPa, the yield strength is larger than or equal to 740 MPa, the ductility is larger than or equal to 10%, and the impact energy is larger than 60 J. And the obtained forging stock is uniform in structure, the material is not cracked in the forging process, and the yield and the impact toughness after annealing are improved.

Description

Technical Field

[0001] The invention belongs to the technical field of titanium alloy hot processing, and specifically relates to a 9-ton or larger Ti80 titanium alloy forging blank with high impact toughness and a manufacturing method thereof. Background Art

[0002] Ti80 titanium alloy is a 780MPa marine near-α titanium alloy with excellent strength, toughness and weldability. Its nominal composition is Ti-6Al-2Zr-1Mo-3Nb. The alloy has an impact toughness of KV2 and a fracture toughness of K IC and stress corrosion fracture toughness K ISCC The welding performance and other indicators are better than those of TC4 ELI alloy, and it is suitable for making submersible pressure hulls and hull structural parts.

[0003] With the rapid development of shipbuilding and marine engineering, the demand for large-sized and heavy Ti80 forgings and plates is increasing, and correspondingly, large-sized and heavy high-quality forging billets are required. Currently, the widely used Ti80 alloy forging billets generally weigh less than 2 tons, and the engineering preparation technology for the extra-large Ti80 titanium alloy forging billets with a finished product weight of more than 8 tons is not yet mature.

[0004] First of all, compared with materials such as steel, titanium alloy has low thermal conductivity, high temperature sensitivity, and a narrow hot processing window. Especially when the size of the billet increases, the deformation effect of the forging billet and the uniformity of the internal temperature distribution are difficult to guarantee. It is easy to have problems such as poor forgeability in the core of the material and uneven organization of different parts of the material due to multiple forgings, which directly affects the uniformity of the subsequent rolled plate organization.

[0005] Secondly, Ti80 titanium alloy is a near-α-type titanium alloy, which is prone to cracks during the forging process, and it is difficult to control the defects of the forging blank.

[0006] Thirdly, Ti80 titanium alloy has a large deformation resistance. If the forging process design is unreasonable, the forging pressure will increase sharply, resulting in inability to forge or requiring forging equipment of more than 10,000 tons, which limits the preparation of the billet.

[0007] In addition, components used in the fields of ships and marine engineering are subject to the impact of waves and floating objects during service, which places high demands on the impact toughness of materials. From forgings to forgings and rolled plates, their organization and impact toughness have certain heredity. If the impact toughness of the forging is poor, there is a great risk that the impact toughness of forgings or rolled plates will not meet the requirements.

[0008] Chinese patent 202311397391.0 discloses a forging method for a large-size Ti80 titanium alloy forging blank, including blank forging, intermediate forging and finished product forging. Among them, during the forging process of the intermediate blank, the blank is forged below the phase change point, which is possible for ingots below 8 tons (7-ton ingots are used in the embodiment), but for ingots above 9 tons, the pressure during upsetting in the two-phase region can reach more than 8,000 tons, and conventional forging equipment cannot meet the requirements. After the intermediate blank is forged, water quenching is used, which is not a big problem for titanium alloys such as TC4, but for Ti80 titanium alloys with a large cracking tendency, there are problems such as water quenching cracking, subsequent surface difficulty in processing, and large material loss.

[0009] Chinese patent CN111906225 discloses a forging method for an ultra-large Ti80 titanium alloy forging blank, which also includes blank forging, intermediate forging and finished product forging. In the intermediate forging process, 6 to 9 forgings are first performed in the single-phase region, and then 3 to 5 forgings are performed in the two-phase region. The intermediate forging adopts a "high-low" forging process, and the number of forgings is large, which easily causes uneven material structure and poor forgeability in the core of the material, resulting in a low material yield and high cost.

[0010] Chinese patent 202311199508.4 discloses a method for forging low anisotropic titanium alloy billets for ships. A forging method that combines multiple deformation methods such as "high-low-high-low" cyclic deformation, reversing upsetting, diagonal drawing and flattening is adopted to reduce the anisotropy of titanium alloy plates prepared from forging billets. The "high-low-high-low" cyclic deformation method is suitable for ingots below 8 tons, but for larger billets, there are also problems such as two-phase region ("low") upsetting. In addition, the above-mentioned process uses a large amount of reversing upsetting, which has problems such as material cracking and low yield.

[0011] Chinese patent CN111230012B discloses a forging method for Ti80 titanium alloy. The method uses deformation from the phase transition point to the phase transition point to ensure sufficient deformation in each fire. The obtained rod has uniform structure in all parts, the primary α phase is equiaxed, and its content is between 60% and 80%. The impact toughness after annealing is ≥35J / cm 2 This patent is only for rods, and the impact toughness obtained is not high.

[0012] Chinese patent CN113755709B discloses a method for preparing a high impact toughness Ti80 titanium alloy bar, which controls the oxygen content and other impurity elements of the bar, and combines high-temperature forging and high-temperature annealing in the two-phase region to adjust the phase ratio and phase morphology, thereby improving the impact toughness of the bar without reducing the strength of the Ti80 alloy. This patent is also only for bars, and its effectiveness for large forging billets remains to be verified.

[0013] In summary, there are still many problems in the manufacturing of high impact toughness Ti80 titanium alloy forging billets above 9 tons (9~17 tons) and extra-large specifications (thickness 200~500mm, width 1000~2500mm, length 2000~4000mm), which makes it difficult to meet the needs of shipbuilding and marine engineering fields. Summary of the invention

[0014] The purpose of the present invention is to provide a Ti80 titanium alloy forging blank with high impact toughness of extra-large size above 9 tons and a manufacturing method, so as to improve the uniformity of the structure and the impact toughness of the large-size forging blank above 9 tons, prevent the material from cracking during the forging process, and improve the yield rate; the obtained titanium alloy forging blank has a uniform equiaxed microstructure, a primary α phase content of 70-90%, a short side size of 12-20 μm, an aspect ratio of less than 1.5, and the tensile strength of each position of the titanium alloy forging blank after annealing is ≥840 MPa, the yield strength is ≥740 MPa, the elongation is ≥10%, and the impact energy is >60 J.

[0015] To achieve the above purpose, the technical solution of the present invention is as follows: A method for manufacturing a Ti80 titanium alloy forging blank with a super large specification and high impact toughness of 9 tons or more, comprising the following steps: S1) Titanium alloy ingot The diameter of Ti80 titanium alloy ingot is Φ960~1060mm and the weight is 9~17 tons; S2) Forging The Ti80 titanium alloy ingot is subjected to 2-5 times of upsetting, the upsetting holding temperature is 1050-1180° C., the upsetting method is flat anvil upsetting plus transverse drawing, the upsetting deformation amount of each time is 30-55%, and the last time of upsetting is followed by air cooling to obtain the first forging blank; S3) Intermediate forging The first forging blank is subjected to 3-4 times of upsetting at 20-50°C above the phase transformation point. The upsetting method is flat anvil upsetting plus transverse drawing. The deformation of each upsetting is 30-55%. After the last upsetting, the blank is air-cooled to obtain the second forging blank. S4) Finished product forging The second forging billet is longitudinally stretched for 3 to 5 times at 30 to 60°C below the phase transformation point, with a deformation of 10 to 30% in each fire and a total deformation of ≥50%, and air-cooled to obtain the forging billet.

[0016] Preferably, in step S1), the Ti80 titanium alloy ingot is obtained by at least three vacuum consumable smelting processes.

[0017] Preferably, the mass percentage of each component in the Ti80 titanium alloy ingot is: 6.0%≤Al≤6.3%, 2.8%≤Nb≤3.2%, 1.9%≤Zr≤2.1%, 1.0%≤Mo≤1.5%, 0<Si≤0.03%, 0<Fe≤0.25%, 0<C≤0.10%, 0<N≤0.05%, 0<H≤0.010%, 0.06≤O≤0.10%, and the balance is Ti and unavoidable impurities.

[0018] Preferably, in step S2), the forging process adopts cooling upsetting, the holding temperature of the first upsetting is 1150-1180°C, and the furnace is returned after each upsetting, and the holding temperature is 20-50°C lower than the holding temperature of the previous upsetting; the holding time t=(0.15-0.5)×H, wherein t is in min, and H is the thickness of the forging blank in mm.

[0019] Preferably, in step S2), the first forging blank is an octagonal blank.

[0020] Preferably, in step S3), after each upsetting and drawing, the cross-section of the forging blank is a flat square, and the ratio of its long side to its short side is 1.2-1.8.

[0021] Preferably, in step S3), the same holding temperature is maintained in the furnace after each upsetting and drawing, and the holding time is t=(0.15-0.5)×H, wherein t is in min, and H is the thickness of the forging blank in mm.

[0022] Preferably, in steps S2) and S3), during each upsetting process, the upsetting speed is 30-40 mm / s, and the upsetting process is paused 2-3 times, and each pause time is 3-8 seconds.

[0023] Preferably, in step 3), the air cooling time is ≥ 1 h.

[0024] Preferably, in step 4), the deformation amount of each fire is 10-30%, during the longitudinal drawing process of each fire, the deformation amount of the first pass is 1.5-4%, the deformation amount of the last pass is 0.5-2%, and the deformation amount of the remaining passes is 5-15%, the feed amount is 1 / 3-1 / 2 of the anvil width, and the drawing pressing speed is 50-70 mm / s.

[0025] The titanium alloy forging blank obtained by the present invention has a thickness of 200-500 mm, a width of 1000-2500 mm, and a length of 2000-4000 mm; The titanium alloy forging blank has a uniform equiaxed microstructure, a primary α phase content of 70-90%, a short side dimension of 12-20 μm, and an aspect ratio of less than 1.5; After annealing, the tensile strength of the titanium alloy forging blank at each position is ≥840MPa, the yield strength is ≥740MPa, the elongation is ≥10%, and the impact energy is >60J.

[0026] In the manufacturing method of the present invention: The present invention selects Ti80 titanium alloy ingots with a diameter of Φ960~1060mm (weight 9~17 tons) to meet the needs of large-size and large-weight Ti80 forging blanks in the field of ships and marine engineering. The mass percentage of each component in the titanium alloy ingot is: 6.0%≤Al≤6.3%, 2.8%≤Nb≤3.2%, 1.9%≤Zr≤2.1%, 1.0%≤Mo≤1.5%, 0<Si≤0.03%, 0<Fe≤0.25%, 0<C≤0.10%, 0<N≤0.05%, 0<H≤0.010%, 0.06≤O≤0.10%, and the balance is Ti and unavoidable impurities. On the one hand, the content of Al, Nb, Zr, and Mo is preferred to ensure strength, and on the other hand, the content of O is appropriately reduced to improve impact toughness, but too low is not conducive to strength, so the lower limit of O content is selected at 0.06%.

[0027] The titanium alloy ingot is obtained through at least three vacuum self-consumption processes to ensure component uniformity.

[0028] Step S2) Design idea of ​​blank forging: The Ti80 titanium alloy ingot is subjected to 2-5 times of upsetting, the upsetting holding temperature is 1050-1180°C, the upsetting method is flat anvil upsetting plus transverse drawing, the upsetting deformation of each time is controlled at 30-55%, and the last time of upsetting is followed by air cooling to obtain the first forging blank.

[0029] (1) Upsetting and drawing holding temperature: For large-sized titanium alloy ingots, the melting and solidification time is long, the cast structure is extremely coarse, and the grain width can reach several centimeters. When heated and forged at 1050~1180℃, the material is in the β single-phase region. On the one hand, the β grains continue to grow, and on the other hand, the β grains are elongated along the direction of metal flow after deformation, and dynamic recrystallization occurs under certain conditions.

[0030] (2) Deformation: Controlling the deformation of each upsetting and drawing process within 30-55% can achieve the purpose of breaking and refining the as-cast structure of the ingot. If the deformation is less than 30%, the recrystallization will not be complete; if the deformation is greater than 55%, the billet is prone to folding during the upsetting process, and the surface is prone to cracking during the subsequent drawing process.

[0031] (3) Deformation method: The upsetting method is flat anvil upsetting plus transverse drawing to improve the uniformity of the structure. After upsetting, the blank forms a deformation dead zone where it contacts the upper and lower anvils. The schematic diagram of the blank shape and strain distribution obtained by the traditional process using longitudinal drawing is shown in Figure 1 As shown in FIG. 1 , a concave deformation dead zone is likely to appear at the end, and a folding hole is subsequently formed and is difficult to eliminate. The schematic diagram of the blank shape and strain distribution obtained by the transverse drawing of the present invention is shown in FIG. Figure 2 As shown, it is beneficial for the material at the end of the blank to bulge outward, and the structure after deformation is more uniform.

[0032] Furthermore, cooling forging is adopted between each fire, and the holding temperature of the first fire upsetting is controlled to be 1150~1180℃. After each fire upsetting, the steel is returned to the furnace, and the holding temperature is 20~50℃ lower than the holding temperature of the previous fire; the deformation of each fire is 30~55%, and the holding time t=(0.15~0.5)×H, where t is in min, H is the thickness of the forging blank in mm, and the formula is only substituted into the coefficient for calculation, without the unit. The open blank forging adopts cooling upsetting, and the temperature reduction range of each upsetting is 20~50℃. On the one hand, it can inhibit the excessive growth of the recrystallized grains formed in the previous fire forging process to a certain extent, and on the other hand, it also ensures the smooth recrystallization in the current fire forging process. The holding time of upsetting is based on the burn-through. If the time is too long, the grains will grow and affect the final organization.

[0033] Step S3) Design idea of ​​intermediate forging: The first forging blank obtained is subjected to 3-4 times of upsetting and drawing at 20-50°C above the phase transformation point. The upsetting and drawing method is flat anvil upsetting plus transverse drawing. The upsetting and drawing deformation in each fire is controlled at 30-55%. After the last fire upsetting and drawing, the second forging blank is obtained by air cooling.

[0034] (1) Upsetting temperature: The purpose of multiple upsetting of the billet in the single-phase region is to further refine the β grains and improve the uniformity of the billet structure. In order to prevent the growth of recrystallized β grains, the forging temperature is selected to be 20~50℃ above the phase transformation point.

[0035] (2) Deformation: In selecting the deformation amount of upsetting and drawing, on the one hand, a larger deformation amount is considered to increase strain energy and promote recrystallization of the material to refine the grains; on the other hand, surface defects are avoided. Therefore, the deformation amount of upsetting and drawing per fire is controlled at 30~55%.

[0036] (3) Deformation method: In order to improve the forgeability of the blank, the upsetting and drawing forging method still selects flat anvil upsetting plus transverse drawing, but the blank section is selected as a flat square, and the ratio of the long and short sides is selected as 1.2~1.8. On the one hand, this section selection is conducive to saving forging time and preventing the temperature of some areas from dropping below the phase transformation point during the forging process, causing uneven organization and surface cracking; on the other hand, during the upsetting and flattening process, the reduction during drawing can be increased. The large reduction makes the internal deformation of the blank sufficient and increases the forgeability; finally, the thickness of the thin section becomes smaller, the reheating time is shortened, and the excessive growth of grains is avoided.

[0037] (4) Cooling method: air cooling is used after forging in the single-phase region. Accelerating the cooling rate will help inhibit the growth of recrystallized β grains, while increasing the nucleation points during the β→α transformation and inhibiting the growth of α lamellae, obtaining thinner grain boundary α and intracrystalline α lamellae, and providing easily broken lamellae for subsequent two-phase deformation. Common cooling methods include air cooling, air cooling and water cooling. Water cooling will increase the risk of surface cracking. Therefore, air cooling is used after forging in the single-phase region. In order to ensure the effect of air cooling, the air cooling time is preferably ≥1h.

[0038] Step S4) Design idea of ​​finished product forging: The second forging blank obtained is longitudinally stretched for 3 to 5 times at 30 to 60° C. below the phase transformation point, with a deformation amount of 10 to 30% in each fire and a total deformation amount of ≥50%, and air-cooled to obtain the forging blank.

[0039] (1) Drawing temperature: The drawing temperature should be 30~60℃ below the phase transition point. If the temperature is too low, the deformation resistance will be large and the material will easily crack. If the temperature is too high, the α-lamellar content will be low and the crushing effect will be poor.

[0040] (2) Deformation: Under the premise of ensuring the deformation requirements of the previous steps, the total deformation of ≥50% in the finished forging stage can achieve sufficient crushing of the lamellar structure. Design 3 to 5 fires of longitudinal drawing, and control the deformation of each fire to 10 to 30% to ensure the surface quality of the intermediate billet and the finished thickness slab during the deformation process and the forgeability of the core.

[0041] Further, during each longitudinal drawing process, the deformation amount of the first pass is 1.5-4%, the deformation amount of the last pass is 0.5-2%, and the deformation amount of the remaining passes is 5-15%. The feed amount is 1 / 3-1 / 2 of the anvil width, and the drawing pressing speed is 50-70 mm / s. The blank structure cooled from the single-phase region in the intermediate forging of step S3) is a lamellar Widmanstatten structure with poor plasticity. The deformation amount of the first pass is 1.5-4%. The first pass adopts a small reduction amount, and the deformation is mainly concentrated on the surface to break the lamellar layer of the surface layer and improve the plasticity of the surface layer. After that, the reduction amount is increased, and the deformation amount of each pass is controlled at 5-15% to ensure the forging permeability of the core of the blank. The deformation amount of the last pass is controlled at 0.5-2% to ensure the surface flatness and surface quality of the blank. The feed amount is selected to ensure the forging permeability of the core. The selection of the pressing speed, if the speed is too high, there is a possibility of heating in the core. Once the phase transition point is exceeded, the forging blank is scrapped. If the speed is too low, the billet will cool easily during the drawing process, the deformation resistance will increase, and the forging pressure will increase sharply, resulting in the inability to forge or the need for forging equipment of more than 10,000 tons, which limits the preparation of the billet. On the other hand, the billet forged at low temperature is prone to cracking.

[0042] Compared with the prior art, the present invention has the following beneficial effects: In the prior art forging process of Ti80 titanium alloy, in the intermediate forging process, the forging heating temperature is alternately above and below the phase transformation point. This method forging large-sized ingots will lead to uneven material structure and poor forgeability in the core.

[0043] The present invention adopts the method of blank forging, intermediate forging and finished product forging, combined with the deformation method, cooling method, deformation amount per fire and total deformation amount control in the forging process, so that the structure of the super-large Ti80 titanium alloy above 9 tons can be fully crushed and refined in the forging process, and the uniformity of the blank structure is improved, so that the structure of the surface layer and the core of the titanium alloy is uniform and fine, and the toughness of the core of the super-large Ti80 titanium alloy after annealing is improved.

[0044] In the process of blank forging, the present invention controls the upsetting and drawing mode to flat anvil upsetting plus transverse drawing, and adopts a larger deformation amount, with the deformation amount of each fire being 30-55%, so as to fully break and refine the structure and make the structure more uniform.

[0045] During the intermediate forging process, the forging heating temperature is controlled in the high temperature zone of 20~50℃ above the phase transformation point, and the deformation is increased. The deformation of each upsetting and drawing is controlled at 30~55%. After 3~4 upsetting and drawing, the deformation mode of upsetting / flat square upsetting plus transverse drawing is combined to fully break the forged structure, refine the β grains and improve the uniformity of the blank structure. After upsetting and drawing, sufficient air cooling is carried out to refine the precipitated lamellar structure and improve the lamellar structure crushing effect of the subsequent finished product forging deformation in the two-phase zone.

[0046] During the forging process of the finished product, the forging temperature is controlled in the two-phase region, and the deformation method adopts longitudinal stretching. The deformation amount of each fire is controlled at 10~30%, and the total deformation amount is ≥50%, so as to fully break the lamellar layer and improve the uniformity of the forging blank structure.

[0047] For Ti80 titanium alloy, the size and uniformity of the primary α phase of the forging blank will be inherited to the rolled state and even the heat-treated state, which will eventually affect the impact toughness of the finished product. Therefore, controlling the size and distribution of the primary α phase of the forging blank is the key to obtaining high impact toughness of the forged state and the finished product. During impact, the nucleation position of the crack is mainly concentrated near the primary α phase boundary. The larger the size of the primary α phase and the more uneven the distribution, the easier it is for the holes to germinate, and the lower the impact toughness of the material. The present invention realizes the manufacture of Ti80 titanium alloy forging blanks of extra-large specifications above 9 tons by controlling the deformation mode, deformation amount and cooling mode in the blank forging, intermediate forging and finished product forging. The obtained forging blank has uniform microstructure and small primary α phase size, the short side size is 12~20μm, and the aspect ratio is less than 1.5, which improves the impact toughness of the forging blank after annealing.

[0048] The forging blanks produced by using Ti80 titanium alloy ingots with a super large size of 9 tons or above have a thickness of 200~500mm, a width of 1000~2500mm, and a length of 2000~4000mm. After annealing, the tensile strength of the titanium alloy forging blanks at each position is ≥840MPa, the yield strength is ≥740MPa, the elongation is ≥10%, and the impact energy is >60J.

[0049] The total cumulative number of upsetting and drawing of the blank forging and intermediate forging is controlled within 5 to 9 times, and there is no need for reversing upsetting and drawing, which avoids material cracking, makes process control easier, and increases the yield rate. In addition, the upsetting temperature before forging the finished product is relatively high, which avoids the need for large-tonnage equipment to forge through the core of an extra-large ingot in the traditional process of forging at low temperature. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 It is a schematic diagram of the shape and strain distribution of the blank after longitudinal drawing deformation; Figure 2 This is a schematic diagram of the shape and strain distribution of the blank after transverse drawing deformation; Figure 3 The appearance and morphology of the Ti80 titanium alloy forging blank with a thickness of 450 mm prepared in Example 1 of the present invention; Figure 4 The microstructure of the Ti80 titanium alloy forging blank with a thickness of 450 mm prepared in Example 1 of the present invention; Figure 5 The appearance and morphology of the Ti80 titanium alloy forging blank with a thickness of 400 mm prepared in Example 2 of the present invention; Figure 6 The microstructure of the Ti80 titanium alloy forging blank with a thickness of 400 mm prepared in Example 2 of the present invention; Figure 7 The microstructure of the Ti80 titanium alloy forging blank with a thickness of 300 mm prepared in Example 3 of the present invention; Figure 8 The microstructure of the Ti80 titanium alloy forging billet with a thickness of 300 mm prepared in the comparative example. DETAILED DESCRIPTION

[0051] The present invention will be further described below in conjunction with the embodiments and drawings.

[0052] The composition of the Ti80 titanium alloy used in the embodiments of the present invention and the comparative examples is shown in Table 1. Tables 2, 3 and 4 are the specific control parameters of the processes of the embodiments of the present invention and the comparative examples. Table 5 is the properties of the titanium alloys obtained in the embodiments of the present invention and the comparative examples.

[0053] Example 1 A method for manufacturing a Ti80 titanium alloy forging billet with a specification of 450×2000×2500 comprises the following steps: S1) Preparation of titanium alloy ingot The diameter of Ti80 titanium alloy ingot is Φ1060mm, the weight is 13 tons, and the phase transition point is T β 990℃; S2) Forging The Ti80 titanium alloy ingot obtained in step S1) is subjected to 3 times of upsetting; The first upsetting and drawing process: the upsetting and drawing holding temperature is 1180℃, and the holding time is 15h after reaching the temperature. The flat anvil is used for a first upsetting deformation, and the deformation amount is 55%. After upsetting, the blank is transversely drawn to 1200 octagonal. The second upsetting and drawing process: the upsetting and drawing holding temperature is 1130℃, and the temperature is kept for 3.5h after reaching the temperature. The flat anvil is used for a first upsetting deformation, and the deformation amount is 55%. After upsetting, the blank is horizontally drawn to 1200 octagonal. The third upsetting and drawing process: the upsetting and drawing holding temperature is 1080℃, and the temperature is kept for 4.0h after reaching the temperature. The flat anvil is used for a first upsetting deformation, and the deformation amount is 55%. After upsetting, the blank is transversely drawn to 1200 octagonal. After forging, air-cooling to room temperature is performed to obtain a first forging billet; S3) Intermediate forging The first forging blank obtained is subjected to 4 times of upsetting and drawing; The first upsetting process: the upsetting temperature is 1020℃, the holding time is 16h, the upsetting deformation is 45%, and the blank is transversely drawn after upsetting to obtain a blank with a cross-sectional size of 1000×1200mm; Second upsetting and drawing: After the first forging, the blank is returned to the furnace and kept at 1020℃ for 3 hours. The blank is subjected to upsetting deformation once using a flat anvil with a deformation amount of 35%. After upsetting, the blank is stretched transversely to a blank with a cross-sectional size of 1000×1200mm. The third fire upsetting and drawing: after the second fire forging, the blank is returned to the furnace, and the temperature is kept at 1020℃ for 3 hours. The flat anvil is used for a first upsetting deformation, and the deformation amount is 35%. After upsetting, the blank is transversely drawn into a blank with a cross-sectional size of 1000×1200mm; The fourth upsetting and drawing process: after the second forging process, the blank is returned to the furnace and kept at a temperature of 1020°C for 3 hours. The blank is subjected to a first upsetting deformation using a flat anvil with a deformation amount of 35%. After upsetting, the blank is stretched transversely into a blank with a cross-sectional size of 1000×1200mm. After forging, the billet is air-cooled for 3 hours to obtain the second forging billet; S4) Finished product forging The second forging blank is obtained and longitudinally stretched for three times; The first drawing process: the drawing temperature is 960℃. During the drawing process, the deformation of the first pass is 1.5%, the deformation of the second and third passes is 12~13%, and the deformation of the last pass is 0.7%. The thickness of the slab after the first drawing process is 750mm. The feed amount during the drawing process is 1 / 3~1 / 2 of the anvil width. The drawing pressing speed is 50~70mm / s. Second fire drawing: drawing temperature 950℃, during drawing, the deformation of the first pass is 3.3%, the deformation of the second and third passes is 11~14%, the deformation of the last pass is 1%, the thickness of the slab after the second fire drawing is 550mm, the feed amount during the drawing process is 1 / 3~1 / 2 of the anvil width, and the drawing pressing speed is 50~70mm / s; The third drawing process: the drawing temperature is 950℃. During the drawing process, the deformation of the first pass is 1.8%, the deformation of the second pass is 9.3%, the deformation of the third pass is 5.1%, and the deformation of the last pass is 1.1%. The thickness of the slab after the third drawing process is 460mm. The feeding amount during the drawing process is 1 / 3~1 / 2 of the anvil width, and the drawing pressing speed is 50~70mm / s; After longitudinal drawing, the billet is air-cooled, and the specifications of the forging billet after shaping and milling are 450×2000×2500mm.

[0054] Figure 3 This is the appearance morphology of the Ti80 titanium alloy forging blank prepared in Example 1 of the present invention. Figure 4 The microstructure pictures of the surface and 1 / 2 thickness position of the Ti80 titanium alloy forging blank prepared in Example 1 of the present invention show that the obtained forging blank structure is a uniform equiaxed structure consisting of a β matrix and an ellipsoidal primary α phase, with a primary α phase content of 70% and a grain size of 12-20 μm.

[0055] Example 2 A method for manufacturing a Ti80 titanium alloy forging billet with a specification of 400×1850×2650 comprises the following steps: S1) Preparation of titanium alloy ingot The diameter of Ti80 titanium alloy ingot is Φ1060mm, the weight is 11 tons, and the phase transition point is T β 987℃; S2) Forging The Ti80 titanium alloy ingot obtained in step S1) is subjected to 4 times of upsetting; The first upsetting and drawing process: the upsetting and drawing holding temperature is 1160℃, and the temperature is kept for 15h after reaching the temperature. The flat anvil is used for a first upsetting deformation, and the deformation amount is 55%. After upsetting, the blank is transversely drawn to 1100 octagonal. The second upsetting and drawing process: the upsetting and drawing holding temperature is 1130℃, and the temperature is kept for 3.0h after reaching the temperature. The flat anvil is used for a first upsetting deformation with a deformation amount of 50%. After upsetting, the blank is horizontally drawn to 1100 octagonal. The third upsetting and drawing process: the upsetting and drawing holding temperature is 1080℃, and the temperature is kept for 3.0h after reaching the temperature. The flat anvil is used for a first upsetting deformation with a deformation amount of 50%. After upsetting, the blank is horizontally drawn to 1100 octagonal. The 4th upsetting and drawing process: the upsetting and drawing holding temperature is 1050℃, and the temperature is kept for 4.0h after reaching the temperature. The flat anvil is used for upsetting deformation once, and the deformation amount is 35%. After upsetting, the blank is horizontally drawn to 1100 octagonal. After forging, air-cooling to room temperature is performed to obtain a first forging billet; S3) Intermediate forging The first forging blank obtained is subjected to three times of upsetting and drawing; The first upsetting process: the upsetting temperature is 1030℃, the holding time is 12h, the upsetting deformation is 42%, and the blank is transversely drawn after upsetting to obtain a blank with a cross-sectional size of 950×1100mm; Second fire upsetting and drawing: After the first fire forging, the blank is returned to the furnace, and the temperature is kept at 1030℃ for 3.5 hours. The flat anvil is used for a first upsetting deformation with a deformation amount of 33%. After upsetting, the blank is transversely drawn into a blank with a cross-sectional size of 950×1100mm. The third fire upsetting and drawing: after the second fire forging, the blank is returned to the furnace, and the temperature is kept at 1030℃ for 3.5 hours. The flat anvil is used for a first upsetting deformation, and the deformation amount is 33%. After upsetting, the blank is transversely drawn into a blank with a cross-sectional size of 950×1200mm; After forging, the billet is air-cooled for 4 hours to obtain the second forging billet; S4) Finished product forging The second forging blank is obtained and longitudinally stretched for 4 times; The first drawing process: the drawing temperature is 950℃. During the drawing process, the deformation of the first pass is 1.6%, the deformation of the second and third passes is 7~7.5%, and the deformation of the last pass is 0.6%. The thickness of the slab after the first drawing process is 800mm. The feed amount during the drawing process is 1 / 3~1 / 2 of the anvil width. The drawing pressing speed is 50~70mm / s. Second fire drawing: drawing temperature 950℃, during drawing, the deformation of the first pass is 2.7%, the deformation of the second and third passes is 11~14%, the deformation of the last pass is 1%, the thickness of the slab after the second fire drawing is 550mm, the feed amount during the drawing process is 1 / 3~1 / 2 of the anvil width, and the drawing pressing speed is 50~70mm / s; The third drawing process: the drawing temperature is 940℃. During the drawing process, the deformation of the first pass is 1.8%, the deformation of the second pass is 9.3%, the deformation of the third pass is 7.1%, and the deformation of the last pass is 1.1%. The thickness of the slab after the third drawing process is 450mm. The feed amount during the drawing process is 1 / 3~1 / 2 of the anvil width. The drawing pressing speed is 50~70mm / s. 4th fire drawing: drawing temperature 940℃, during drawing, the deformation of the first pass is 2.2%, the deformation of the second pass is 11.4%, the deformation of the third pass is 6.4%, and the deformation of the last pass is 1.4%. The thickness of the slab after the 4th fire drawing is 410mm. The feeding amount during the drawing process is 1 / 3~1 / 2 of the anvil width, and the drawing pressing speed is 50~70mm / s; After longitudinal drawing, the billet is air-cooled, and the specifications of the forging billet after shaping and milling are 400×1950×2650mm.

[0056] Figure 5 This is the appearance morphology of the Ti80 titanium alloy forging blank prepared in Example 2 of the present invention. Figure 6 The microstructure pictures of the surface layer and 1 / 2 thickness position of the Ti80 titanium alloy forging billet prepared in Example 2 of the present invention are uniform equiaxed structure, consisting of a β matrix and an ellipsoidal primary α phase. The primary α phase content is as high as 90%, and the grain size is 12 to 20 μm.

[0057] Example 3 The manufacturing method of Ti80 titanium alloy forging billet with specifications of 300×1800×3300 comprises the following steps: S1) Preparation of titanium alloy ingot The diameter of Ti80 titanium alloy ingot is Φ960mm, the weight is 9.7 tons, and the phase transition point is T β 991℃; S2) Forging The Ti80 titanium alloy ingot obtained in step S1) is subjected to two upsetting processes; The first upsetting and drawing process: the upsetting and drawing holding temperature is 1150℃, and the temperature is kept for 10 hours after reaching the temperature. The flat anvil is used for a first upsetting deformation, and the deformation amount is 35%. After upsetting, the blank is transversely drawn to 1000 octagonal. The second upsetting and drawing process: the upsetting and drawing holding temperature is 1130℃, and the temperature is kept for 2.5h after reaching the temperature. The flat anvil is used for a first upsetting deformation, and the deformation amount is 35%. After upsetting, the blank is horizontally drawn to 1000 octagonal. After forging, air-cooling to room temperature is performed to obtain a first forging billet; S3) Intermediate forging The first forging blank obtained is subjected to three times of upsetting and drawing; The first upsetting process: the upsetting temperature is 1020℃, the holding time is 12h, the upsetting deformation is 40%, and the blank is transversely drawn after upsetting to obtain a blank with a cross-sectional size of 800×1200mm; Second fire upsetting and drawing: After the first fire forging, the blank is returned to the furnace and kept at a temperature of 1020℃ for 2.5 hours. A flat anvil is used for a first upsetting deformation with a deformation amount of 40%. After upsetting, the blank is transversely drawn into a blank with a cross-sectional size of 800×1200mm. The third upsetting and drawing process: after the second forging process, the blank is returned to the furnace and kept at a temperature of 1020℃ for 2.5 hours. The blank is subjected to a first upsetting deformation using a flat anvil with a deformation amount of 40%. After upsetting, the blank is stretched transversely to a blank with a cross-sectional size of 800×1200mm. After forging, the billet is air-cooled for 2.5 hours to obtain the second forging billet; S4) Finished product forging The second forging blank is obtained and longitudinally stretched for three times; First fire drawing: drawing temperature is 950℃, during drawing, the deformation of the first pass is 1.9%, the deformation of the second and third passes is 12~14%, and the deformation of the last pass is 1.7%. The thickness of the slab after the first fire drawing is 580mm. The feed amount during the drawing process is 1 / 3~1 / 2 of the anvil width, and the drawing pressing speed is 50~70mm / s; Second fire drawing: drawing temperature is 940℃, during drawing, the deformation of the first pass is 1.7%, the deformation of the second and third passes is 12~15%, and the deformation of the last pass is 1.2%. The thickness of the slab after the second fire drawing is 420mm. The feed amount during the drawing process is 1 / 3~1 / 2 of the anvil width, and the drawing pressing speed is 50~70mm / s; The third drawing process: the drawing temperature is 940℃. During the drawing process, the deformation of the first pass is 2.4%, the deformation of the second and third passes is 11~13%, and the deformation of the last pass is 1.6%. The thickness of the slab after the third drawing process is 315mm. The feed amount during the drawing process is 1 / 3~1 / 2 of the anvil width, and the drawing pressing speed is 50~70mm / s. After longitudinal drawing, the billet is air-cooled, and the specifications of the forging billet after shaping and milling are 300×1800×3300mm.

[0058] Figure 7 The microstructure pictures of the surface layer and 1 / 2 thickness position of the Ti80 titanium alloy forging billet prepared in Example 3 of the present invention are uniform equiaxed structure, consisting of a β matrix and an ellipsoidal primary α phase. The primary α phase content is as high as 80%, and the grain size is 12 to 20 μm.

[0059] Example 4 The manufacturing method of Ti80 titanium alloy forging billet with specifications of 500×2200×2500 comprises the following steps: S1) Preparation of titanium alloy ingot The diameter of Ti80 titanium alloy ingot is Φ1060mm, the weight is 15 tons, and the phase transition point is T β 990℃; S2) Forging The Ti80 titanium alloy ingot obtained in step S1) is subjected to 5 times of upsetting; The first upsetting and drawing process: the upsetting and drawing holding temperature is 1180℃, and the temperature is kept for 15h after reaching the temperature. The flat anvil is used for a first upsetting deformation, and the deformation amount is 45%. After upsetting, the blank is transversely drawn to 1200 octagonal. The second upsetting and drawing process: the upsetting and drawing holding temperature is 1150℃, and the temperature is kept for 4 hours after reaching the temperature. The flat anvil is used for a first upsetting deformation, and the deformation amount is 45%. After upsetting, the blank is transversely drawn to 1200 octagonal. The third upsetting and drawing process: the upsetting and drawing holding temperature is 1130℃, and the temperature is kept for 4 hours after reaching the temperature. The flat anvil is used for a first upsetting deformation, and the deformation amount is 45%. After upsetting, the blank is transversely drawn to 1200 octagonal. The 4th upsetting and drawing process: the upsetting and drawing holding temperature is 1100℃, and the temperature is kept for 4h after reaching the temperature. The flat anvil is used for a first upsetting deformation, and the deformation amount is 40%. After upsetting, the blank is horizontally drawn to 1200 octagonal. The fifth upsetting and drawing process: the upsetting and drawing holding temperature is 1080℃, and the temperature is kept for 4 hours after reaching the temperature. The flat anvil is used for a first upsetting deformation, and the deformation amount is 30%. After upsetting, the blank is transversely drawn to 1200 octagonal. After forging, air-cooling to room temperature is performed to obtain a first forging billet; S3) Intermediate forging The first forging blank obtained is subjected to 4 times of upsetting and drawing; The first upsetting process: the upsetting temperature is 1030℃, the holding time is 15h, the upsetting deformation is 55%, and the blank is transversely drawn after upsetting to obtain a blank with a cross-sectional size of 1000×1200mm; Second upsetting and drawing: After the first forging, the blank is returned to the furnace and kept at 1030℃ for 3.5 hours. A flat anvil is used for upsetting deformation with a deformation amount of 45%. After upsetting, the blank is transversely drawn into a blank with a cross-sectional size of 1000×1200mm. The third fire upsetting and drawing: after the second fire forging, the blank is returned to the furnace, and the temperature is kept at 1030℃ for 3.5 hours. The flat anvil is used for a first upsetting deformation with a deformation amount of 40%. After upsetting, the blank is transversely drawn into a blank with a cross-sectional size of 1000×1200mm; The fourth upsetting and drawing process: after the second forging process, the blank is returned to the furnace and kept at a temperature of 1030°C for 3.5 hours. The blank is subjected to a first upsetting deformation using a flat anvil with a deformation amount of 35%. After upsetting, the blank is stretched transversely into a blank with a cross-sectional size of 1000×1200mm. After forging, the billet is air-cooled for 3 hours to obtain the second forging billet; S4) Finished product forging The second forging blank is obtained and longitudinally stretched for three times; The first drawing process: the drawing temperature is 950℃. During the drawing process, the deformation of the first pass is 1.5%, the deformation of the second and third passes is 10~12%, and the deformation of the last pass is 1.3%. The thickness of the slab after the first drawing process is 800mm. The feed amount during the drawing process is 1 / 3~1 / 2 of the anvil width. The drawing pressing speed is 50~70mm / s. Second fire drawing: drawing temperature is 950℃, during drawing, the deformation of the first pass is 1.3%, the deformation of the second and third passes is 8~11%, and the deformation of the last pass is 0.8%. The thickness of the slab after the second fire drawing is 600mm, the feed amount during the drawing process is 1 / 3~1 / 2 of the anvil width, and the drawing pressing speed is 50~70mm / s; The third drawing fire: the drawing temperature is 940℃. During drawing, the deformation of the first pass is 1.7%, the deformation of the second and third passes is 7~8.5, and the deformation of the last pass is 1%. The thickness of the slab after the third drawing fire is 510mm. The feed amount during the drawing process is 1 / 3~1 / 2 of the anvil width, and the drawing pressing speed is 50~70mm / s.

[0060] After longitudinal drawing, the billet is air-cooled, and the forging billet is shaped and milled to a size of 500×2200×2500 mm. The microstructure of the forging billet surface and 1 / 2 thickness is a uniform equiaxed structure, consisting of a β matrix and an ellipsoidal primary α phase, with a primary α phase content of up to 75% and a grain size of 12~20μm.

[0061] Example 5 The manufacturing method of Ti80 titanium alloy forging billet with specification of 200×1900×4000 comprises the following steps: S1) Preparation of titanium alloy ingot The diameter of Ti80 titanium alloy ingot is Φ960mm, the weight is 9 tons, and the phase transition point is T β 990℃; S2) Forging The Ti80 titanium alloy ingot obtained in step S1) is subjected to 3 times of upsetting; The first upsetting and drawing process: the upsetting and drawing holding temperature is 1180℃, and the temperature is kept for 12 hours after reaching the temperature. The flat anvil is used for a first upsetting deformation, and the deformation amount is 45%. After upsetting, the blank is horizontally drawn to 1000 octagonal. The second upsetting and drawing process: the upsetting and drawing holding temperature is 1150℃, and the temperature is kept for 4 hours after reaching the temperature. The flat anvil is used for a first upsetting deformation, and the deformation amount is 45%. After upsetting, the blank is horizontally drawn to 1000 octagonal. The third upsetting and drawing process: the upsetting and drawing holding temperature is 1130℃, and the temperature is kept for 4 hours after reaching the temperature. The flat anvil is used for a first upsetting deformation, and the deformation amount is 40%. After upsetting, the blank is horizontally drawn to 1000 octagonal. After forging, air-cooling to room temperature is performed to obtain a first forging billet; S3) Intermediate forging The first forging blank obtained is subjected to three times of upsetting and drawing; The first upsetting process: the upsetting temperature is 1030℃, the holding time is 14h, the upsetting deformation is 35%, and the blank is transversely drawn after upsetting to obtain a blank with a cross-sectional size of 800×1400mm; Second fire upsetting and drawing: After the first fire forging, the blank is returned to the furnace and kept at a temperature of 1030℃ for 3.5 hours. A flat anvil is used for a first upsetting deformation with a deformation amount of 35%. After upsetting, the blank is transversely drawn into a blank with a cross-sectional size of 800×1400mm. The third fire upsetting and drawing: after the second fire forging, the blank is returned to the furnace, and the temperature is kept at 1030℃ for 3.5 hours. The flat anvil is used for a first upsetting deformation with a deformation amount of 30%. After upsetting, the blank is transversely drawn into a blank with a cross-sectional size of 800×1400mm; After forging, the billet is air-cooled for 3 hours to obtain the second forging billet; S4) Finished product forging The second forging blank is obtained and longitudinally stretched for 5 times; The first drawing process: the drawing temperature is 950℃. During the drawing process, the deformation of the first pass is 1.9%, the deformation of the second and third passes is 12~14%, and the deformation of the last pass is 1.7%. The thickness of the slab after the first drawing process is 600mm. The feed amount during the drawing process is 1 / 3~1 / 2 of the anvil width. The drawing pressing speed is 50~70mm / s. Second fire drawing: drawing temperature is 950℃, during drawing, the deformation of the first pass is 1.7%, the deformation of the second and third passes is 11~15%, and the deformation of the last pass is 1.1%. The thickness of the slab after the second fire drawing is 450mm. The feed amount during the drawing process is 1 / 3~1 / 2 of the anvil width, and the drawing pressing speed is 50~70mm / s; The third drawing process: the drawing temperature is 940℃. During the drawing process, the deformation of the first pass is 2.2%, the deformation of the second and third passes is 10~12%, and the deformation of the last pass is 1.4%. The thickness of the slab after the third drawing process is 350mm. The feed amount during the drawing process is 1 / 3~1 / 2 of the anvil width. The drawing pressing speed is 50~70mm / s. 4th fire drawing: drawing temperature 940℃, during drawing, the deformation of the first pass is 1.4%, the deformation of the second to third pass is 6~10%, and the deformation of the last pass is 1.9%. The thickness of the slab after the 4th fire drawing is 265mm. The feeding amount during the drawing process is 1 / 3~1 / 2 of the anvil width, and the drawing pressing speed is 50~70mm / s; 5th drawing fire: drawing temperature is 940℃, during drawing, the deformation of the first pass is 1.9%, the deformation of the second and third passes is 9~12%, and the deformation of the last pass is 1.4%. After the 4th drawing fire, the thickness of the slab is 207mm. The feed amount during the drawing process is 1 / 3~1 / 2 of the anvil width, and the drawing pressing speed is 50~70mm / s.

[0062] After longitudinal drawing, the billet is air-cooled, and the forging billet is shaped and milled to a size of 200×1900×40000 mm. The microstructure of the forging billet surface and 1 / 2 thickness is a uniform equiaxed structure, consisting of a β matrix and an ellipsoidal primary α phase, with a primary α phase content of up to 70% and a grain size of 12 to 20 μm.

[0063] Comparative Example 1 A method for manufacturing a Ti80 titanium alloy forging billet with a specification of 400×1850×2650 comprises the following steps: S1) Preparation of titanium alloy ingot The diameter of Ti80 titanium alloy ingot is Φ1060mm, the weight is 12 tons, and the phase transition point is T β 989℃; S2) Forging The Ti80 titanium alloy ingot obtained in step S1) is subjected to 4 times of upsetting, and the process parameters are the same as those in Example 2; After forging, air-cooling to room temperature is performed to obtain a first forging billet; S3) Intermediate forging The first forging blank obtained was subjected to 4 times of upsetting and drawing, and the process parameters were the same as those in Example 2, except that the forging blank was air-cooled to room temperature, and a second forging blank was obtained with a cross-sectional size of 650×1800 mm; S4) Finished product forging The second forging blank is obtained and longitudinally stretched for 2 times with the same process parameters as in Example 3; The first drawing process: the drawing temperature is 950℃. During the drawing process, the deformation of the first pass is 1.5%, the deformation of the second and third passes is 9~11%, and the deformation of the last pass is 1.2%. The thickness of the slab after the first drawing process is 500mm. The feed amount during the drawing process is 1 / 3~1 / 2 of the anvil width. The drawing pressing speed is 50~70mm / s. The second drawing process: the drawing temperature is 950℃. During the drawing process, the deformation of the first pass is 1%, the deformation of the second and third passes is 8~11%, and the deformation of the last pass is 1.2%. The thickness of the slab after the second drawing process is 410mm. The feed amount during the drawing process is 1 / 3~1 / 2 of the anvil width, and the drawing pressing speed is 50~70mm / s.

[0064] After shaping and milling, the specifications of the forging blank are 400×1850×2650mm. Figure 8 The microstructures of the surface layer and 1 / 2 thickness of the forging blank prepared as a comparative example show that the flakes on the surface layer and 1 / 2 thickness are not completely broken, especially the structure at 1 / 2 thickness is extremely uneven.

[0065] Comparative Example 2 The manufacturing method of Ti80 titanium alloy forging billet with specifications of 300×1800×3300 comprises the following steps: S1) Preparation of titanium alloy ingot The diameter of Ti80 titanium alloy ingot is Φ960mm, the weight is 9.5 tons, and the phase transition point is T β 989℃; S2) Forging The Ti80 titanium alloy ingot obtained in step S1) is subjected to two upsetting processes; The first upsetting and drawing: heating temperature is 1150℃, and the temperature is kept for 10 hours after reaching the temperature. The flat anvil is used for upsetting deformation, and the deformation amount is 35%. After upsetting, the blank is horizontally drawn to 1000 octagonal. The second upsetting and drawing: heating temperature is 1130℃, and the temperature is kept for 2.5h after reaching the temperature. The flat anvil is used for upsetting deformation, and the deformation amount is 35%. After upsetting, the blank is horizontally drawn to 1000 octagonal. After forging, air-cooling to room temperature is performed to obtain a first forging billet; S3) Intermediate forging The first forging blank obtained is subjected to two-time upsetting and drawing; The first upsetting process: heating temperature is 1020℃, holding time is 12h, upsetting deformation is 45%, and the blank is transversely drawn after upsetting to obtain a blank with a cross-sectional size of 800×1200mm; Second upsetting and drawing: After the first forging, the blank is returned to the furnace, heated to 1020℃, kept warm for 2.5 hours, and subjected to a first upsetting deformation using a flat anvil, with a deformation amount of 35%. After upsetting, the blank is transversely drawn into a blank with a cross-sectional size of 800×1200mm; After forging, the billet is air-cooled for 2.5 hours to obtain the second forging billet; S4) Finished product forging The second forging blank is obtained and longitudinally stretched for three times with the same process parameters as in Example 3; The specifications of the forging blank after shaping and milling are 300×1800×3300mm. The microstructure analysis of the forging blank shows that the surface layer and the 1 / 2 thick layer have not been completely broken, especially the structure at the 1 / 2 thick layer is extremely uneven.

[0066] In Comparative Example 1, air cooling is used instead of wind cooling after intermediate forging, and the drawing reduction of the finished product is too small, which cannot fully break up the lamellar structure of the two-phase zone; the forging blank obtained in Comparative Example 1 has uneven performance, and the strength and impact performance of the core of the forging blank do not meet the requirements.

[0067] In Comparative Example 2, only 4 upsetting and drawing fires were performed during the open forging and intermediate forging processes. The number of forging fires was small, the total deformation was small, the forged structure was not fully broken, the β grains were not refined, and the uniformity of the billet structure was not improved. The strength and impact properties of the surface and core positions of the forged billet in Comparative Example 2 did not meet the standard requirements.

[0068] The embodiments described above are only descriptions of the preferred implementation modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

[0069]

[0070]

[0071]

[0072]

[0073]

Claims

1. A method for manufacturing a Ti80 titanium alloy forging blank with a super large specification and high impact toughness of 9 tons or more, characterized in that: The steps include: S1) Titanium alloy ingot The diameter of Ti80 titanium alloy ingot is Φ960~1060mm and the weight is 9~17 tons; S2) Forging The Ti80 titanium alloy ingot is subjected to 2-5 times of upsetting, the upsetting holding temperature is 1050-1180° C., the upsetting method is flat anvil upsetting plus transverse drawing, the upsetting deformation amount of each time is 30-55%, and the last time of upsetting is followed by air cooling to obtain the first forging blank; S3) Intermediate forging The first forging blank is subjected to 3-4 times of upsetting at 20-50°C above the phase transformation point. The upsetting method is flat anvil upsetting plus transverse drawing. The deformation of each upsetting is 30-55%. After the last upsetting, the blank is air-cooled to obtain the second forging blank. S4) Finished product forging The second forging billet is longitudinally stretched for 3 to 5 times at 30 to 60°C below the phase transformation point, with a deformation of 10 to 30% in each fire and a total deformation of ≥50%, and air-cooled to obtain the forging billet.

2. The method for manufacturing the 9-ton or larger Ti80 titanium alloy forging blank with high impact toughness as claimed in claim 1, characterized in that: In step S1), the Ti80 titanium alloy ingot is obtained by at least three vacuum consumable smelting processes.

3. The method for manufacturing a Ti80 titanium alloy forging billet with a super large size and high impact toughness of 9 tons or more as claimed in claim 1 or 2, characterized in that: The mass percentages of the components in the Ti80 titanium alloy ingot are: Al 6.0-6.3%, Nb 2.8-3.2%, Zr1.9%-2.1%, Mo 1.0%-1.5%, 0<Si≤0.03%, 0<Fe≤0.25%, 0<C≤0.10%, 0<N≤0.05%, 0<H≤0.010%, O 0.06-0.10%, and the balance is Ti and unavoidable impurities.

4. The method for manufacturing a 9-ton or larger Ti80 titanium alloy forging blank with high impact toughness as claimed in claim 1, characterized in that: In step S2), the forging process adopts cooling upsetting, the holding temperature of the first upsetting is 1150-1180°C, and the furnace is returned to the furnace for holding after each upsetting, and the holding temperature is 20-50°C lower than the holding temperature of the previous upsetting; the holding time t = (0.15-0.5) × H, where t is in min and H is the thickness of the forging blank in mm.

5. The method for manufacturing a Ti80 titanium alloy forging billet with a super large size and high impact toughness of 9 tons or more as claimed in claim 1 or 4, characterized in that: In step S2), the first forging blank is an octagonal blank.

6. The method for manufacturing the 9-ton or larger Ti80 titanium alloy forging blank with high impact toughness as claimed in claim 1, characterized in that: In step S3), after each upsetting and drawing, the cross section of the forging blank is a flat square, and the ratio of its long side to its short side is 1.2-1.

8.

7. The method for manufacturing a 9-ton or larger Ti80 titanium alloy forging blank with high impact toughness as claimed in claim 1, characterized in that: In step S3), the same holding temperature is maintained for each reheating after upsetting and drawing, and the holding time is t=(0.15-0.5)×H, where t is in min and H is the thickness of the forging blank in mm.

8. The method for manufacturing a 9-ton or larger Ti80 titanium alloy forging billet with high impact toughness as claimed in claim 1, 4, 6 or 7, characterized in that: In steps S2) and S3), during each upsetting process, the upsetting speed is 30-40 mm / s, and the upsetting process is paused 2-3 times, and each pause time is 3-8 seconds.

9. The method for manufacturing a 9-ton or larger Ti80 titanium alloy forging billet with high impact toughness as claimed in claim 1, 6 or 7, characterized in that: In step 3), the air cooling time is ≥ 1h.

10. The method for manufacturing a 9-ton or larger Ti80 titanium alloy forging blank with high impact toughness as claimed in claim 1, characterized in that: In step 4), during each longitudinal drawing process, the deformation amount of the first pass is 1.5-4%, the deformation amount of the last pass is 0.5-2%, and the deformation amount of the remaining passes is 5-15%. The feed amount is 1 / 3-1 / 2 of the anvil width, and the drawing pressing speed is 50-70 mm / s.

11. A Ti80 titanium alloy forging blank with extra-large specifications and high impact toughness manufactured by the method according to any one of claims 1 to 10, characterized in that: The titanium alloy forging blank has a thickness of 200-500 mm, a width of 1000-2500 mm, and a length of 2000-4000 mm; The titanium alloy forging blank has a uniform equiaxed microstructure, a primary α phase content of 70-90%, a short side dimension of 12-20 μm, and an aspect ratio of less than 1.5; After annealing, the tensile strength of the titanium alloy forging blank at each position is ≥840MPa, the yield strength is ≥740MPa, the elongation is ≥10%, and the impact energy is >60J.

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