Forging method of ultra-long two-phase titanium alloy forged plate

Abstract

The invention relates to a forging method of an ultra-long two-phase titanium alloy forged plate. The forging method comprises the steps of high-temperature cogging forging, recrystallization forging, homogenizing forging and pre-forming forging and forming forging. According to the method, a reversing drawing-out process is introduced in the high-temperature cogging and low-temperature preforming processes, so that uniform deformation of the interior of a material is effectively promoted, the mechanical properties of a forged plate in the length direction, the width direction and the thickness direction reach high consistency, and meanwhile, the mechanical properties of the forged plate in the length direction, the width direction and the thickness direction are greatly improved. And the temperature, deformation, pressing speed and other parameters in the forging process are precisely controlled, forging defects are reduced, the yield is further improved, the production efficiency is improved through the whole process, the production cost is reduced, the batch stability of forged plates can be guaranteed, and the requirements of the aerospace field and other fields for high-performance titanium alloy forgings are met.

Description

Technical Field

[0001] The invention relates to the field of nonferrous metal processing, and in particular to a forging method for a two-phase titanium alloy forging plate. Background Art

[0002] Titanium alloys have been widely used in aerospace, marine engineering, chemical industry, medical and other fields due to their excellent comprehensive properties, such as high strength, low density, good corrosion resistance and excellent high temperature performance. In particular, α+β two-phase titanium alloys have become the preferred material for manufacturing aircraft structures, engine parts, chemical equipment and other key components due to their balanced mechanical properties and good process performance.

[0003] With the advancement of industrial technology and the growth of demand for new materials, the performance requirements for titanium alloy materials are getting higher and higher. In the field of aerospace, in order to improve the performance of aircraft, reduce structural weight, and increase payload, higher requirements are placed on the specifications and performance of titanium alloy forgings. Ultra-long titanium alloy forgings have become a hot topic in materials science and engineering technology research due to their potential application in large structural parts.

[0004] Two-phase titanium alloys generally have excellent strength, toughness and heat resistance. This alloy has an α+β two-phase structure in the annealed state, and good comprehensive mechanical properties can be obtained through proper heat treatment. For example, TC4 titanium alloy has high strength and low density, which makes it widely used as a structural material in the aerospace field, especially in aircraft wing beams, engine compressor discs, aircraft landing gear and other key load-bearing parts.

[0005] Forging is an important process to improve metal structure and material performance. For titanium alloy, forging can not only break the casting structure and refine the grain, but also optimize the internal defects of the material by controlling the deformation process, and improve the fatigue performance and fracture toughness of the material. The traditional titanium alloy forging process includes basic processes such as upsetting, drawing, punching and expanding. Through the combination of these processes, forgings of different shapes and specifications can be manufactured.

[0006] However, with the increasing demand for ultra-long titanium alloy forgings in industry, traditional forging processes face many challenges. For example, ultra-long forgings are prone to uneven deformation during the forging process, resulting in uneven organization and performance. In addition, improper heating and cooling control during the forging process may also lead to a decrease in material properties. Therefore, developing an efficient, uniform and controllable forging process for ultra-long titanium alloy forgings is the key to meeting the needs of modern industry.

[0007] Although the existing forging process can meet the production needs of two-phase titanium alloy forgings to a certain extent, there are still some limitations in the manufacture of ultra-long forged plates. For example, the traditional forging process often requires multiple heating and forging, which not only increases the production cost, but also may lead to unstable material properties. In addition, the traditional forging process has high requirements on equipment and is highly dependent on the technical level of operators. These factors limit the production efficiency and quality of ultra-long titanium alloy forged plates. Summary of the invention

[0008] The purpose of the present invention is to avoid the shortcomings of the prior art and provide a forging method for an ultra-long two-phase titanium alloy forging plate by adopting a reversing drawing process to achieve uniformity of the internal structure of the forging plate and improve the mechanical properties and dimensional stability of the forging plate.

[0009] To achieve the above object, the technical solution adopted by the present invention is: a forging method of an ultra-long dual-phase titanium alloy forging plate, comprising the following steps:

[0010] Step 1: High temperature forging:

[0011] The two-phase titanium alloy ingot is subjected to at least one upsetting and drawing forging process at a temperature of 1100° C. to 1200° C., the deformation amount of upsetting and drawing in a single upsetting process is 20% to 45%, the pressing speed is 10 mm / s to 50 mm / s, and air cooling is performed after forging to obtain a two-phase titanium alloy forged plate;

[0012] The relationship between the amount of pressure h per hammer during the upsetting deformation and the maximum diagonal length D of the cross section after drawing is: h = (0.1-0.2) × D, which is used to ensure uniform flow of the material during drawing and minimize deformation stress;

[0013] Step 2: Recrystallization forging:

[0014] Under the heating temperature condition of 30-50° C. below the β-transformation temperature, the two-phase titanium alloy billet is subjected to one-time upsetting and drawing forging, the upsetting deformation amount and the deformation amount during drawing in the single-fire are both 20%-45%, and the pressing speed is both 10mm / s-50mm / s; after forging, the billet is directly returned to the furnace and heated to a temperature 40-80° C. higher than the β-transformation temperature, then taken out of the furnace at a temperature of 40-80° C., and then subjected to at least two upsetting-reversing drawing, the upsetting deformation amount and the deformation amount during drawing in the single-fire are both 25%-45%, and the pressing speed is both 10mm / s-50mm / s, and after forging, the billet is air-cooled or water-cooled to room temperature;

[0015] Wherein, the holding time is t, t = (0.2-0.6) × D, to ensure sufficient recrystallization;

[0016] Step 3: Homogenization forging and preforming forging:

[0017] The two-phase titanium alloy billet after recrystallization forging is subjected to homogenization upsetting forging in at least three times at a heating temperature of 30 to 70°C below the β transformation temperature, with a deformation amount of 30% to 45%, and then air-cooled or water-cooled to room temperature before preforming forging;

[0018] During the preforming forging, the two-phase titanium alloy blank is first heated to 30-70°C below the β transformation temperature, subjected to at least one upsetting and drawing process, the hot material is returned to the furnace for reversing and drawing, and then subjected to at least one flattening process, and after forging, the blank is air-cooled to room temperature, and finally, the blank temperature is heated to 30-70°C below the β transformation temperature, and subjected to at least two flattening processes to obtain a preformed forged plate;

[0019] The forging deformation of each fire is 25% to 40%, and the pressing speed is 10 mm / s to 50 mm / s to make the two-phase titanium alloy billet gradually approach the final material shape and size;

[0020] Step 4: Forming and forging:

[0021] The two-phase titanium alloy billet after preforming forging is subjected to at least one fire deformation of 20% to 40% and a pressing speed of 10 mm / s to 50 mm / s at a temperature of 30 to 70°C below the β transformation temperature for finished product forging, and air-cooled after forging to obtain a two-phase titanium alloy forged plate with a length L ≥ 4000 mm.

[0022] Furthermore, in the step 1, the two-phase titanium alloy ingot is subjected to repeated upsetting and drawing forging for 2 to 3 times at a temperature of 1100°C to 1200°C, and each time of upsetting and drawing forging is performed for at least two upsettings and two drawing to four or eight sides. After forging, the hot material is returned to the furnace and heated to 1100°C to 1200°C for the next upsetting and drawing forging.

[0023] Furthermore, in the single-fire upsetting in step 1, the two-phase titanium alloy ingot is first upset to half of its size, then turned over and upset to its full size, so as to ensure uniform deformation of the entire cross section of the two-phase titanium alloy ingot.

[0024] Furthermore, the height-to-diameter ratio of the blank finally obtained in step 1 is 1.5-2.1, which is used to ensure that there is sufficient deformation during subsequent upsetting and no double bulging phenomenon occurs.

[0025] Furthermore, the one-time upsetting and drawing forging in step 2 is upsetting and drawing forging of at least two upsetting and two drawing to four or eight sides, air cooling after forging, and the height-to-diameter ratio of the obtained two-phase titanium alloy billet is 1.6 to 2.1;

[0026] At least two upsetting and reversing stretching operations are performed to change the longitudinal direction to the transverse direction to four or eight directions, and two reversing operations are performed to return to the original direction.

[0027] Furthermore, in the homogenization upsetting and forging described in step 3, the two-phase titanium alloy billet is repeatedly upsetting and forging for 2 to 3 times, and the final forging temperature is not less than 800° C. to ensure the plasticity and forging quality of the material;

[0028] At the same time, the height-to-diameter ratio of the two-phase titanium alloy billet after homogenization upsetting and forging is 1.5-2.1.

[0029] Furthermore, the flattening performed in step three during the preforming forging is a longitudinal lengthening process.

[0030] Furthermore, the pressing speed in the preforming forging in step three is 10 mm / s to 50 mm / s, and the feed rate is 140 mm to 400 mm, so as to ensure uniform flow of materials and reduce forging defects during the preforming forging process.

[0031] Furthermore, in step 4, the two-phase titanium alloy billet after preforming forging is subjected to 1-2 rounds of finished product forging and then subjected to the next round of finished product forging;

[0032] Among them, the hot material must be returned to the furnace for insulation between each firing. The insulation temperature is 30 to 70°C below the β transformation temperature, and the insulation time is t = 0.2×D.

[0033] Furthermore, in the forging of the finished product, the two-phase titanium alloy billet is first stretched to half its size, then forged to the final required material size, and then leveled with residual heat.

[0034] The beneficial effects of the present invention are:

[0035] 1. Significant improvement in tissue uniformity:

[0036] In the traditional titanium alloy forging process, the unidirectional flow of materials during forging often leads to uneven growth of grains and anisotropy of the structure. This inhomogeneity is particularly evident in ultra-long forgings, which directly affects the mechanical properties of the material, especially in the aerospace and other fields, which have extremely high requirements for the isotropy of the material.

[0037] The present invention effectively promotes uniform deformation inside the material by introducing a reversing drawing process during high-temperature blanking and low-temperature preforming. The reversing drawing process changes the deformation direction of the material so that the material can obtain uniform plastic deformation in all directions, thereby achieving uniform grain refinement and uniform organizational structure. This uniformity is not only reflected in the microscopic grain size and distribution, but also in the macroscopic mechanical properties, so that the mechanical properties of the forged plate in the length direction (L), length-thickness direction (LT) and short-thickness direction (ST) are highly consistent.

[0038] 2. Significant improvement in yield rate:

[0039] The present invention significantly improves the yield rate by optimizing the forging process and introducing the reversing drawing process. The reversing drawing process reduces the uneven deformation during the forging process by changing the deformation direction of the material, thereby reducing the waste of materials. At the same time, the present invention also reduces the generation of forging defects and further improves the yield rate by accurately controlling parameters such as temperature, deformation amount and pressing speed during the forging process.

[0040] 3. Significant improvement in batch stability:

[0041] The present invention significantly improves the batch stability of forged plates by strictly controlling various parameters in the forging process, such as temperature, deformation, pressing speed, etc. In the homogenization forging and preforming forging stages, the present invention controls the deformation and final forging temperature by firing in batches, ensuring that each batch of forged plates can achieve the same organizational state and performance level.

[0042] In summary, the forging method of the present invention can not only improve production efficiency and reduce production costs, but also ensure the batch stability of forged plates, and meet the needs of aerospace and other fields for high-performance titanium alloy forgings. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 This is a low-magnification structural photograph of a forged plate of a specific example of the present invention;

[0044] Figure 2 This is a low-magnification microstructure photo of a forged plate after empty firing;

[0045] Figure 3 This is a high-magnification microstructure photograph of a forged plate of a specific example of the present invention. DETAILED DESCRIPTION

[0046] The principles and features of the present invention are described below in conjunction with the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0047] The present invention aims to solve the challenges encountered by the prior art in the production of ultra-long duplex titanium alloy forgings, especially how to achieve precise control of organization and texture during the forging process, and how to ensure high consistency of mechanical properties of the forgings in the length direction (L), width direction (LT) and thickness direction (ST). Existing processes often fail to ensure the internal quality of ultra-long forgings, resulting in unstable material properties, low yield rate and poor batch stability.

[0048] The present invention introduces a reversing drawing process and implements reversing drawing during the recrystallization forging and low-temperature preforming process to improve the internal structure and performance of the two-phase titanium alloy forging plate. The core of the reversing drawing process is to change the deformation direction of the material at different stages of forging, thereby promoting uniform deformation inside the material and reducing the uneven structure and performance caused by unidirectional deformation. Therefore, these two stages are key steps in forming the performance of the final product.

[0049] At the same time, by precisely controlling the forging temperature, deformation, pressing speed and other parameters, the present invention can achieve uniformity of internal structure and improve the overall performance of the forged plate while ensuring the dimensional accuracy of the forged plate. It aims to improve the production efficiency of ultra-long two-phase titanium alloy forged plates, reduce production costs, and ensure the dimensional stability and batch consistency of the forged plates, meeting the strict requirements of aerospace and other fields for high-performance titanium alloy forgings.

[0050] In order to achieve the above object, the present invention provides the following specific implementation methods:

[0051] Embodiment 1: A forging method for an ultra-long dual-phase titanium alloy forging plate comprises the following steps:

[0052] Step 1: High temperature forging:

[0053] The two-phase titanium alloy ingot is subjected to at least one upsetting and drawing forging process at a temperature of 1100° C. to 1200° C., the deformation amount of upsetting and drawing in a single upsetting process is 20% to 45%, the pressing speed is 10 mm / s to 50 mm / s, and air cooling is performed after forging to obtain a two-phase titanium alloy forged plate;

[0054] Among them, during single-fire upsetting, half of the size of the two-phase titanium alloy ingot is first upset, then turned over and upset to the full size, to ensure uniform deformation of the entire cross section of the two-phase titanium alloy ingot. The relationship between the amount of downstroke h per hammer during upsetting deformation and the maximum diagonal length D of the cross section after elongation is: h = (0.1-0.2) × D, which is used to ensure uniform flow of the material during elongation and minimize deformation stress; the final billet height-to-diameter ratio is 1.5-2.1, which is used to ensure sufficient deformation during subsequent upsetting and no double bulging phenomenon.

[0055] Step 2: Recrystallization forging:

[0056] Under the heating temperature condition of 30-50°C below the β transformation temperature, the two-phase titanium alloy billet is subjected to one-time upsetting and drawing forging, the upsetting deformation amount and the deformation amount during drawing in the single fire are both 20%-45%, and the pressing speed is 10mm / s-50mm / s; after forging, it is directly returned to the furnace and heated to a temperature 40-80°C higher than the β transformation temperature, then taken out of the furnace at a temperature of 40-80°C, and then upsetting-reversing drawing is performed at least twice, the upsetting deformation amount and the deformation amount during drawing in the single fire are both 25%-45%, and the pressing speed is 10mm / s-50mm / s, and after forging, it is air-cooled or water-cooled to room temperature;

[0057] Among them, the holding time is t, t = (0.2 ~ 0.6) × D, which is used to ensure sufficient recrystallization; the first fire upsetting and drawing forging is upsetting and drawing forging with at least two upsettings and two drawing to four or eight sides, air cooling after forging, and the height-to-diameter ratio of the obtained two-phase titanium alloy billet is 1.6-2.1; and then at least two upsetting-reversing drawing is carried out to change the longitudinal direction to the transverse direction to four or eight sides, and the two reversals return to the original direction.

[0058] Step 3: Homogenization forging and preforming forging:

[0059] The two-phase titanium alloy billet after recrystallization forging is subjected to homogenization upsetting forging in at least three times under the heating temperature condition of 30 to 70° C. below the β transformation temperature, with a deformation amount of 30% to 45%, and then air-cooled or water-cooled to room temperature before preforming forging; the height-to-diameter ratio of the two-phase titanium alloy billet after homogenization upsetting forging is 1.5 to 2.1;

[0060] During the preforming forging, the two-phase titanium alloy billet is first heated to 30-70°C below the β transformation temperature, subjected to at least one upsetting and drawing process, the hot material is returned to the furnace for reversing and drawing, and then subjected to at least one flattening process, and after forging, the billet is air-cooled to room temperature, and finally, the billet temperature is heated to 30-70°C below the β transformation temperature, subjected to at least two flattening processes, and thus a preformed forged plate is obtained;

[0061] Among them, the forging deformation amount of each fire is 25%~40%, and the pressing speed is 10mm / s~50mm / s, so as to make the two-phase titanium alloy billet gradually approach the final material shape and size; the pressing speed in preforming forging is 10mm / s~50mm / s, and the feed amount is 140mm~400mm, so as to ensure the uniform flow of materials during the preforming forging process and reduce forging defects.

[0062] Step 4: Forming and forging:

[0063] The two-phase titanium alloy billet after preforming forging is subjected to at least one fire deformation of 20% to 40% and a pressing speed of 10 mm / s to 50 mm / s at a temperature of 30 to 70°C below the β transformation temperature for finished product forging, and air-cooled after forging to obtain a two-phase titanium alloy forged plate with a length L ≥ 4000 mm.

[0064] Among them, in the finished product forging, the two-phase titanium alloy billet is first stretched to half the size, then forged to the final required material size, and then leveled with residual heat.

[0065] Embodiment 2: Same as Embodiment 1, except that:

[0066] In step one, the two-phase titanium alloy ingot is subjected to upsetting and drawing forging at a temperature of 1100°C to 1200°C for 2 to 3 cycles, wherein each time the upsetting and drawing forging is performed at least twice upsetting and twice drawing to four or eight sides, and the hot material after forging is returned to the furnace and heated to 1100°C to 1200°C for the next upsetting and drawing forging.

[0067] In the homogenization upsetting and forging in step 3, the two-phase titanium alloy billet is repeatedly upsetting and forging for 2 to 3 times, and the final forging temperature is not less than 800° C. to ensure the plasticity and forging quality of the material;

[0068] The flattening process performed during preforming forging is the longitudinal lengthening process.

[0069] In step 4, the two-phase titanium alloy billet after preforming forging is subjected to 1-2 rounds of finished product forging and then subjected to the next round of finished product forging;

[0070] Among them, the hot material must be returned to the furnace for insulation between each firing. The insulation temperature is 30 to 70°C below the β transformation temperature, and the insulation time is t = 0.2×D.

[0071] like Figure 1-3 To further illustrate the technical solution and technical effects of the present invention, the present invention provides the following specific examples:

[0072] Specific example: This example selects the most typical two-phase titanium alloy TC4 titanium alloy, and uses TC4 titanium alloy ingot forging. The ingot specification is Φ820×1194mm and the single weight is 2800kg. The specific forging process is as follows:

[0073] (1) Billet forging

[0074] It is completed in three fires. In the first fire, the two-phase titanium alloy ingot is heated to 1150℃ and kept warm. Two upsets and two draws are performed to four sides. The deformation is controlled at 20%-40%, and the height-to-diameter ratio of the billet is controlled at about 1.9. After forging, the hot material is returned to the furnace and heated to 1100℃, and two upsets and reversing draws are performed to eight sides. The deformation is controlled at 40%. Finally, the height-to-diameter ratio of the billet is controlled at about 1.9. After forging, the hot material is returned to the furnace and heated to 1050℃ for insulation. Two upsets and two draws are performed to eight sides. The deformation is 40%, and the height-to-diameter ratio of the billet is controlled at about 1.9. Air cooling is used after forging.

[0075] (2) Recrystallization forging

[0076] First, the billet in step (i) is heated to 950°C and kept warm. After being taken out of the furnace, it is subjected to two upsetting and two drawing to eight directions, and the deformation is controlled at 35% to 40%. The height-to-diameter ratio after forging is controlled at about 1.9. The hot material is returned to the furnace and heated to 1050°C and kept warm for 360 minutes. After being taken out of the furnace, it is subjected to upsetting-reversing drawing to eight directions, and the deformation is controlled at 40%. Water cooling is used after forging.

[0077] (III) Homogenization forging and preforming forging

[0078] The billet after the treatment in step (ii) is forged three times to an octave of 734×1329 mm, the heating temperature is 950°C, the deformation is about 37%, and water cooling is used after forging; then the billet is heated to 950°C for a set of upsetting and drawing, the hot material is returned to the furnace for reversing and flattening (L direction to ST direction), the hot material is returned to the furnace after forging, and then flattening is performed again with a deformation of about 35%, air cooling is used after forging, and then the billet is heated to 950°C again for two rounds of flattening to a deformation of about 35%, and air cooling is used after forging.

[0079] (IV) Forming forging

[0080] For the blanks that have completed step (iii), after being heated at 950°C, they are flattened to the finished product size with a deformation of about 20%. In the middle, they need to be reheated in the furnace to ensure the forging temperature. The final product specifications are 168×704×4660mm.

[0081] Table 1 is a table of mechanical properties of the forged plate obtained in this specific example:

[0082] Table 1

[0083]

[0084] It can be seen from Table 1 that the performance of the forged plate at the head, middle and tail parts has very excellent consistency. At the same time, the mechanical properties in the transverse, longitudinal and height directions also have good consistency, indicating that the material organization is uniform and there is no obvious texture.

[0085] like Figure 1-Figure 3As shown, Figure 1 The middle is a low-power microstructure photo of the forged plate in this example. Figure 2 This is a low-power photo of the forged plate being fired. Figure 1 , 2 It can be seen that the macrostructure of forged plates and the macrostructure of air-fired plates meet the standard requirements, without obvious defects or abnormal structures.

[0086] Figure 3 This is a high-magnification microstructure photograph of the forged plate in this example. It can be seen from the figure that the microstructure of the forged plate in three directions is well consistent, the primary α phase is well spheroidized, and there is no obvious texture.

[0087] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A forging method for an ultra-long dual-phase titanium alloy forging plate, characterized in that: The following steps are involved: Step 1: High temperature forging: The two-phase titanium alloy ingot is subjected to at least one upsetting and drawing forging process at a temperature of 1100° C. to 1200° C., the deformation amount of upsetting and drawing in a single upsetting process is 20% to 45%, the pressing speed is 10 mm / s to 50 mm / s, and air cooling is performed after forging to obtain a two-phase titanium alloy forged plate; The relationship between the amount of pressure h per hammer during the upsetting deformation and the maximum diagonal length D of the cross section after drawing is: h = (0.1-0.2) × D, which is used to ensure uniform flow of the material during drawing and minimize deformation stress; Step 2: Recrystallization forging: Under the heating temperature condition of 30-50° C. below the β-transformation temperature, the two-phase titanium alloy billet is subjected to one-time upsetting and drawing forging, the upsetting deformation amount and the deformation amount during drawing in the single-fire are both 20%-45%, and the pressing speed is both 10mm / s-50mm / s; after forging, the billet is directly returned to the furnace and heated to a temperature 40-80° C. higher than the β-transformation temperature, then taken out of the furnace at a temperature of 40-80° C., and then subjected to at least two upsetting-reversing drawing, the upsetting deformation amount and the deformation amount during drawing in the single-fire are both 25%-45%, and the pressing speed is both 10mm / s-50mm / s, and after forging, the billet is air-cooled or water-cooled to room temperature; Wherein, the holding time is t, t = (0.2-0.6) × D, to ensure sufficient recrystallization; Step 3: Homogenization forging and preforming forging: The two-phase titanium alloy billet after recrystallization forging is subjected to homogenization upsetting forging in at least three times at a heating temperature of 30 to 70°C below the β transformation temperature, with a deformation amount of 30% to 45%, and then air-cooled or water-cooled to room temperature before preforming forging; During the preforming forging, the two-phase titanium alloy blank is first heated to 30-70°C below the β transformation temperature, subjected to at least one upsetting and drawing process, the hot material is returned to the furnace for reversing and drawing, and then subjected to at least one flattening process, and after forging, the blank is air-cooled to room temperature, and finally, the blank temperature is heated to 30-70°C below the β transformation temperature, and subjected to at least two flattening processes to obtain a preformed forged plate; The forging deformation of each fire is 25% to 40%, and the pressing speed is 10 mm / s to 50 mm / s, so that the two-phase titanium alloy billet gradually approaches the final material shape and size; Step 4: Forming and forging: The two-phase titanium alloy billet after preforming forging is subjected to at least one fire deformation of 20% to 40% and a pressing speed of 10 mm / s to 50 mm / s at a temperature of 30 to 70°C below the β transformation temperature forging, and air-cooled after forging to obtain a two-phase titanium alloy forged plate with a length L ≥ 4000 mm.

2. The forging method of the ultra-long dual-phase titanium alloy forging plate according to claim 1, characterized in that: In the step 1, the two-phase titanium alloy ingot is subjected to repeated upsetting and drawing forging for 2 to 3 times at a temperature of 1100° C. to 1200° C., and each time of upsetting and drawing forging is performed for at least two upsetting and two drawing to four or eight sides. After forging, the hot material is returned to the furnace and heated to 1100° C. to 1200° C. for the next time of upsetting and drawing forging.

3. The forging method of the ultra-long dual-phase titanium alloy forging plate according to claim 1, characterized in that: During the single-fire upsetting in step 1, the two-phase titanium alloy ingot is first upset to half of its size, then turned over and upset to its full size, to ensure uniform deformation of the entire cross section of the two-phase titanium alloy ingot.

4. The forging method of the ultra-long dual-phase titanium alloy forging plate according to claim 1, characterized in that: The step 1 finally obtains a billet with a height-to-diameter ratio of 1.5 to 2.1, which is used to ensure that there is sufficient deformation during subsequent upsetting and that double bulging does not occur.

5. The forging method of the ultra-long dual-phase titanium alloy forging plate according to claim 1, characterized in that: The one-time upsetting and drawing forging in step 2 is upsetting and drawing forging with at least two upsetting and two drawing to four or eight sides, air cooling after forging, and the height-to-diameter ratio of the obtained two-phase titanium alloy billet is 1.6-2.1; At least two upsetting and reversing stretching operations are performed to change the longitudinal direction to the transverse direction to four or eight directions, and two reversing operations are performed to return to the original direction.

6. The forging method of the ultra-long dual-phase titanium alloy forging plate according to claim 1, characterized in that: In the homogenization upsetting and forging described in step 3, the two-phase titanium alloy billet is repeatedly upsetting and forging for 2 to 3 times, and the final forging temperature is not less than 800° C. to ensure the plasticity and forging quality of the material; At the same time, the height-to-diameter ratio of the two-phase titanium alloy billet after homogenization upsetting and forging is 1.5-2.

1.

7. The forging method of the ultra-long dual-phase titanium alloy forging plate according to claim 1, characterized in that: The flattening process performed in step 3 during the preforming forging is the longitudinal lengthening process.

8. The forging method of the ultra-long dual-phase titanium alloy forging plate according to claim 1, characterized in that: The pressing speed in the preforming forging in step 3 is 10 mm / s to 50 mm / s, and the feed rate is 140 mm to 400 mm, so as to ensure uniform flow of materials and reduce forging defects during the preforming forging process.

9. The forging method of the ultra-long dual-phase titanium alloy forging plate according to any one of claims 1 to 8, characterized in that: In the step 4, the two-phase titanium alloy billet after preforming forging is subjected to 1-2 rounds of finished product forging and then subjected to the next round of finished product forging; Among them, the hot material must be returned to the furnace for insulation between each firing. The insulation temperature is 30 to 70°C below the β transformation temperature, and the insulation time is t = 0.2×D.

10. The forging method of the ultra-long dual-phase titanium alloy forging plate according to claim 9, characterized in that: In the finished product forging, the two-phase titanium alloy billet is firstly stretched to half the size, then forged to the final required material size, and then leveled by residual heat.

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