Preparation method of TA15 titanium alloy large-size flat plate forging blank

Abstract

The application discloses a preparation method of a TA15 titanium alloy large-size flat plate forging blank, and comprises the following steps: firstly, 2 times of upsetting and drawing forging is performed on a cast ingot during roughing forging, so that an intermediate blank is obtained; then, 4-8 times of upsetting and drawing forging is performed on the obtained intermediate blank during intermediate forging, so that a forging blank 1 is obtained; finally, 3 times of drawing forging is performed on the forging blank 1 during forming forging, and after machining, a target-size TA15 titanium alloy large-size flat plate forging blank is obtained; relevant parameters in each stage are strictly controlled, including but not limited to heating temperature, holding time, forging ratio, deformation amount and feeding amount and the like. Compared with the prior art, the application adopts a "reversing upsetting and drawing" technology during intermediate forging, and reasonably distributes the drawing deformation amount according to the thickness of the forging blank during the forming stage, and simultaneously performs small feeding amount and high frequency pressing, so that the uniformity of the forging blank structure is improved, the flaw detection level is improved, and the demand of the aerospace field on the large-size titanium alloy flat plate forging blank is fully met.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of non-ferrous metal processing, and particularly relates to a preparation method of TA15 titanium alloy large-size flat plate forging blank, and is particularly suitable for preparing a TA15 titanium alloy flat plate forging blank with a thickness of 80mm-300mm, a width of 700mm-1700mm, a length of 1400mm-3500mm, and good uniformity of microstructure, performance and ultrasonic flaw detection. BACKGROUND

[0002] TA15 titanium alloy is a medium-strength near-alpha titanium alloy, and the nominal composition is Ti-6.5Al-2Zr-1Mo-1V. The main strengthening mechanism is the solid solution strengthening of the alpha stabilizing element Al, and a certain amount of neutral element Zr and beta stabilizing elements Mo and V are also added to improve the process performance. The alloy belongs to a high Al equivalent near-alpha titanium alloy, has good thermal stability and weldability of alpha titanium alloy, and also has process plasticity close to alpha+beta titanium alloy.

[0003] TA15 titanium alloy is widely used in the field of aerospace technology due to its high specific strength, good thermal stability, corrosion resistance and welding performance. In recent years, with the continuous development of design and manufacturing technology of China's aerospace industry, the requirements for large-scale and integration of new aircraft load-bearing frames and other forgings are put forward, and the development and production of new forgings require the use of large-size titanium alloy flat plate forging blanks with uniform microstructure and performance. At present, in the production of TA15 titanium alloy flat plate forging blanks, in order to ensure the equiaxial degree of primary alpha phase in the microstructure, the blank is subjected to multi-pass single-direction upsetting and elongation (i.e. axial upsetting and axial elongation) in the two-phase region. When the blank is upset forged, the end region of the blank in contact with the anvil is a difficult deformation zone, and the middle part of the blank is a severe deformation zone. Therefore, multi-pass single-direction upsetting will cause the deformation difference between the end and middle parts of the blank to increase, thereby reducing the uniformity of the microstructure, performance and flaw detection at different positions.

[0004] Therefore, the present application provides a preparation method of TA15 titanium alloy large-size flat plate forging blank to overcome the defects of the prior art. SUMMARY

[0005] The present application aims to overcome the shortcomings of the prior art and provide a preparation method of TA15 titanium alloy large-size flat plate forging blank. The preparation method starts from the machining process and solves the problem of poor uniformity of microstructure, performance and ultrasonic flaw detection of the forging blank prepared by the prior art.

[0006] The purpose of the present application is achieved by the following technical solutions:

[0007] The application discloses a preparation method of a TA15 titanium alloy large-size flat plate forging blank, and the raw material of the TA15 titanium alloy large-size flat plate forging blank is a TA15 titanium alloy ingot with a weight of 4-10 tons, a size of Phi 720mm-Phi 1020mm and chemical components meeting the requirements of the 11-CL-045D standard.

[0008] Step 1, open die forging

[0009] The ingot is heated and kept for a period of time, and is subjected to two heating and upsetting and elongating processes above the phase transition point, and the upsetting and elongating ratio is controlled to be between 1.1 and 2.2 in each heating and upsetting and elongating process, and the blank is cooled in air after forging, so that an intermediate blank is obtained.

[0010] Step 2, intermediate forging

[0011] The intermediate blank obtained in step 1 is heated to 60 DEG C below the phase transition point to 100 DEG C above the phase transition point and kept for a period of time, and is subjected to 4-8 heating and upsetting and elongating processes, the upsetting and elongating ratio is controlled to be between 1.1 and 2.0 in each heating and upsetting and elongating process, and the final forging temperature is not lower than 650 DEG C, and the blank is air-cooled after each heating and upsetting and elongating process, so that a forging blank 1 is obtained.

[0012] Step 3, forming forging

[0013] The forging blank 1 obtained in step 2 is heated to 20 DEG C to 60 DEG C below the phase transition point and subjected to forming forging, the forming forging is completed through 3 heating and elongating processes, and the final forging temperature is not lower than 650 DEG C in each heating and elongating process, and the blank is air-cooled after forging, so that a forging blank 2 is obtained, and the target-size large-size flat plate forging blank is obtained after machining of the forging blank 2.

[0014] Further, the specific process of the open die forging in step 1 is that the ingot is first heated to 100 DEG C to 200 DEG C above the phase transition point, kept for 400 min to 700 min, and subjected to one heating and upsetting and elongating process, then is reheated to 20 DEG C to 150 DEG C above the phase transition point, kept for 30 min to 180 min, and then is subjected to one heating and upsetting and elongating process, the final forging temperature is not lower than 700 DEG C, and the blank is air-cooled after forging, so that an intermediate blank is obtained.

[0015] Further, the specific process of the 4-8 heating and upsetting and elongating processes in step 2 is that:

[0016] the first heating temperature is 20 DEG C to 60 DEG C below the phase transition point, and the blank is subjected to upsetting and elongating after being kept for 400 min to 700 min;

[0017] the second heating temperature is 20 DEG C to 100 DEG C above the phase transition point, and the blank is subjected to upsetting and elongating after being kept for 300 min to 500 min;

[0018] The heating temperature of the 3th to 8th heating is 20-60 DEG C below the phase transition point, and after holding for 400-700 min, the ''reversing upsetting and drawing'' forging is carried out, that is, after axial upsetting, the drawing is carried out from the radial direction, and then after upsetting, the drawing is carried out from the axial direction.

[0019] Further, in the forming forging in step 3, the large deformation is used to improve the core structure in the large thickness and low resistance stage, and the small deformation is used to eliminate the near-surface deformation dead zone in the small thickness and high resistance stage, and the deformation amounts of the 3th drawing are as follows: the first drawing deformation amount is 30%±10%, the second drawing deformation amount is 20%±8%, and the third drawing deformation amount is 10%±5%.

[0020] Further, in the forming forging in step 3, the small feeding and high frequency drawing technology is used, and the feeding amounts of the 3th drawing are as follows: the first drawing feeding amount is 150-200 mm, the second drawing feeding amount is 100-180 mm, and the third drawing feeding amount is 50-120 mm, and the frequency of the press drawing is 30-70 times / min.

[0021] Further, the specific process of the forming forging in step 3 is as follows:

[0022] The first heating temperature is 20-60 DEG C below the phase transition point, and after holding for 400-700 min, the drawing deformation is carried out; the second heating temperature is 20-60 DEG C below the phase transition point, and after holding for 250-600 min, the drawing deformation is carried out again; and the third heating temperature is 20-60 DEG C below the phase transition point, and after holding for 100-500 min, the final drawing deformation is carried out.

[0023] Further, the preparation method is used for producing the TA15 titanium alloy large-size flat forging billet with a thickness of 80-300 mm, a width of 700-1700 mm and a length of 1400-3500 mm, and the longitudinal room temperature tensile strength of the flat forging billet is greater than 950 MPa, the yield strength is greater than 870 MPa, the longitudinal impact is greater than 45 J / cm2, and the flaw detection level reaches Φ

[0024] 1.2-9dB above.

[0025] Compared with the prior art, the present application has the following beneficial effects:

[0026] The application discloses a preparation method of a TA15 titanium alloy large-size flat plate forging blank. 2 , the low-magnification structure is uniform, the equiaxial primary alpha phase in the high-magnification structure is good, the content is 30% to 65%, the longitudinal room temperature tensile strength is greater than 950 MPa, the yield strength is greater than 870 MPa, the longitudinal impact is greater than 45 J / cm 2 , the flaw detection level is greater than Φ1.2-9dB, and the requirements of the aerospace field on the large-size titanium alloy flat plate forging blank with uniform structure and performance are fully met. BRIEF DESCRIPTION OF DRAWINGS

[0027] The drawings incorporated into the specification and constituting a part of the specification, together with the specification, serve to explain the principles of the application.

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced as follows, and obviously, other drawings can be obtained by those skilled in the art without any creative labor under the premise of the drawings.

[0029] Figure 1 is a preparation method flow chart of a TA15 titanium alloy large-size flat plate forging blank of the application;

[0030] Figure 2 is a low-magnification structure diagram of a 120*850*3500mm forging blank head, middle and tail prepared in the embodiment 1 of the application;

[0031] Figure 3 is a microstructure diagram of thickness upper, middle and lower positions of the 120*850*3500mm forging blank head, middle and tail prepared in the embodiment 1 of the application;

[0032] Figure 4 is a low-magnification structure diagram of a 200*900*2500mm forging blank head, middle and tail prepared in the embodiment 2 of the application;

[0033] Figure 5The microstructure diagrams of the thickness upper, middle and lower positions of the head, middle and tail of the 200*900*2500mm forging blank prepared by the embodiment 2 of the present application are shown in the figure. DETAILED DESCRIPTION

[0034] The exemplary embodiments will be described in detail hereinbelow with reference to the drawings. In the following description, the same numbers refer to the same or similar elements unless otherwise represented. The embodiments described in the following exemplary embodiments do not represent all the embodiments consistent with the present application. Rather, they are merely examples of apparatuses consistent with some aspects of the present application as detailed in the appended claims.

[0035] In order for those skilled in the art to better understand the technical solutions of the present application, the present application will be further described in detail below with reference to the drawings and embodiments.

[0036] Referring to Figure 1 As shown in the figure, the present application provides a preparation method of TA15 titanium alloy large-size flat plate forging blank, which selects 4-10 tons of TA15 titanium alloy ingot with a size of Φ720mm-Φ1020mm and a chemical composition meeting the standard requirements of 11-CL-045D, and the preparation method comprises the following steps:

[0037] Step 1, breakdown forging

[0038] The ingot is forged for 2 times, specifically: the first time, the ingot is heated to 100-200℃ above the phase transition point, and after holding for 400-700min, upsetting and drawing are performed, and the upsetting and drawing ratio is controlled to be 1.1-2.2; the second time, the heating temperature is 20-150℃ above the phase transition point, and after holding for 30-180min, upsetting and drawing are performed again, the upsetting and drawing ratio is controlled to be 1.1-2.2, and the final forging temperature is not lower than 700℃, and after forging, the blank is cooled in air to obtain an intermediate blank.

[0039] Step 2, intermediate forging

[0040] The intermediate blank obtained in step 1 is heated to 60℃ below the phase transition point to 100℃ above the phase transition point, and is forged for 4-8 times, the upsetting and drawing ratio is controlled to be 1.1-2.0 each time, and the final forging temperature is not lower than 650℃, and after each forging, the blank is air-cooled to obtain a forging blank 1.

[0041] The specific process of the 4th to 8th heating forging is as follows: the first heating temperature is 20-60℃ below the phase transition point, and after 400-700 minutes of holding, upsetting and drawing are performed; the second heating temperature is 20-100℃ above the phase transition point, and after 300-500 minutes of holding, upsetting and drawing are performed; the third to eighth heating temperatures are all 20-60℃ below the phase transition point, and after 400-700 minutes of holding, the "reversing upsetting and drawing" forging is performed, that is, after axial upsetting, radial drawing is performed, and then after upsetting, axial drawing is performed.

[0042] Step 3, forming forging

[0043] The forging blank 1 obtained in step 2 is heated to 20-60℃ below the phase transition point and subjected to forming forging, and the forming forging is completed by 3 passes of drawing, and the final forging temperature of each pass is not lower than 650℃, and after forging, air cooling is performed to obtain a forging blank 2, and after machining (such as using a planer or a milling machine), a large-size flat plate forging blank with a target size is obtained.

[0044] The specific process of the 3 passes of drawing is as follows: the first heating temperature is 20-60℃ below the phase transition point, and after 400-700 minutes of holding, drawing deformation is performed, and the deformation amount is set to 30%±10% and the feed amount is set to 150-200mm; the second heating temperature is 20-60℃ below the phase transition point, and after 250-600 minutes of holding, drawing deformation is performed again, and the deformation amount is set to 20%±8% and the feed amount is set to 100-180mm; the third heating temperature is all 20-60℃ below the phase transition point, and after 100-500 minutes of holding, final drawing deformation is performed, and the final drawing deformation amount is set to 10%±5% and the feed amount is set to 50-120mm. The frequency of the press drawing of each pass of the 3 passes of drawing is set to 30-70 times per minute, and during the forming forging, in the large thickness and low resistance stage (the first 2 passes), the core structure is improved by large deformation amount, and in the small thickness and high resistance stage (the last 1 pass), small deformation is used to eliminate the near-surface deformation dead zone, and at the same time, the "small feed, high frequency" drawing technology is used, so that the uniformity indexes of the structure, performance and flaw detection of the finally prepared forging blank are all good.

[0045] In order to further verify the effect of the forging method of the present application, the inventors carried out the following specific examples:

[0046] Example 1 (preparing a flat plate forging blank with a size of 120×850×3500mm)

[0047] Raw material: a 5-ton grade TA15 titanium alloy ingot with a size of Φ720mm and chemical components meeting the standard requirements of 11-CL-045D is selected.

[0048] 1) Blooming forging: After the ingot is sawed into two equal parts, 2 heating times of forging are carried out, specifically: the heating temperature of the first heating time is 1090-1190 °C, after holding for 400-550 min, upsetting and drawing are carried out, the upsetting and drawing forging ratio is controlled to be 1.4-1.5; after being returned to 1010-1140 °C and holding for 30-150 min, upsetting and drawing are carried out again, the upsetting and drawing forging ratio is controlled to be 1.4-1.5, and the final forging temperature is controlled to be above 700 °C, and the material after forging is cooled by air cooling.

[0049] 2) Intermediate forging: the intermediate forging is completed in 4 heating times, specifically:

[0050] the heating temperature of the first heating time is 930-970 °C, after holding for 500-620 min, upsetting and drawing are carried out; the heating temperature of the second heating time is 1010-1090 °C, after holding for 400-500 min, upsetting and drawing are carried out; the heating temperature of the third and fourth heating times is 930-970 °C, after holding for 500-620 min, "reversing upsetting and drawing" is carried out, that is, after axial upsetting, radial drawing is carried out, and then after radial upsetting, axial drawing is carried out. The upsetting and drawing forging ratio of the above heating times is controlled to be 1.4-1.5, and the material after intermediate forging is in the specification of 500x500x1300 mm, the final forging temperature is controlled to be above 650 °C, and after each heating time of forging is completed, cooling is carried out by air cooling.

[0051] 3) Forming forging: the forming forging is completed by 3 heating times of drawing, specifically:

[0052] the heating temperature of the first heating time is 930-970 °C, after holding for 400-520 min, the drawing deformation is 25%, the feed amount is 180 mm, the frequency of pressing machine is 40 times / min, and the final forging temperature is controlled to be above 650 °C; the heating temperature of the second heating time is 930-970 °C, after holding for 260-380 min, the drawing deformation is 16%, the feed amount is 120 mm, the frequency of pressing machine is 50 times / min, and the final forging temperature is controlled to be above 650 °C; the heating temperature of the third heating time is 930-970 °C, after holding for 120-240 min, the drawing deformation is 8%, the feed amount is 60 mm, the frequency of pressing machine is 50 times / min, and the final forging temperature is controlled to be above 650 °C. The obtained material is planed / milled by a planer / milling machine into a forging blank in the specification of 120x850x3500 mm.

[0053] Example 2 (preparation of a flat plate forging blank in the specification of 200x900x2500 mm)

[0054] Raw material: TA15 titanium alloy ingot with Φ920mm and 7 tons, whose chemical composition meets the requirements of 11-CL-045D standard.

[0055] 1) Open-die forging: after the ingot is cut into two equal parts, 2 heating times of forging are carried out, specifically: the heating temperature of the first heating time is 1120-1190℃, after holding for 550-700min, upsetting and drawing are carried out, the upsetting and drawing ratio is controlled to be 1.8-2.0; after holding for 90-180min at 1010-1140℃, upsetting and drawing are carried out again, the upsetting and drawing ratio is controlled to be 1.8-2.0, and the final forging temperature is controlled to be above 700℃, and the material after forging is cooled by air cooling.

[0056] 2) Intermediate forging: the intermediate forging is completed by 7 heating times, specifically:

[0057] the heating temperature of the first heating time is 930-970℃, after holding for 550-700min, upsetting and drawing are carried out; the heating temperature of the second heating time is 1020-1080℃, after holding for 400-500min, upsetting and drawing are carried out; the heating temperature of the third to seventh heating times is 930-970℃, after holding for 550-700min, "reversing upsetting and drawing" is carried out, that is, after axial upsetting, radial drawing is carried out, and then after radial upsetting, axial drawing is carried out. The upsetting and drawing ratio of the above heating times is controlled to be 1.8-2.0, and the material after the seventh heating time is formed into a material with a size of 700×700×1500mm, the final forging temperature is controlled to be above 650℃, and after each heating time of forging is completed, the material is cooled by air cooling.

[0058] 3) Forming forging: the forming forging is completed by 3 heating times of drawing, specifically:

[0059] the heating temperature of the first heating time is 930-970℃, after holding for 550-700min, the drawing deformation is 35%, the feeding amount is 180mm, the frequency of pressing machine is 50 times / min, and the final forging temperature is controlled to be above 650℃; the heating temperature of the second heating time is 930-970℃, after holding for 450-600min, the drawing deformation is 22%, the feeding amount is 150mm, the frequency of pressing machine is 60 times / min, and the final forging temperature is controlled to be above 650℃; the heating temperature of the third heating time is 930-970℃, after holding for 300-450min, the drawing deformation is 12%, the feeding amount is 80mm, the frequency of pressing machine is 60 times / min, and the final forging temperature is controlled to be above 650℃. The obtained material is planed / milled by a planer / milling machine into a forging blank with a size of 200×900×2500mm.

[0060] Result analysis:

[0061] One, macro and microstructure analysis

[0062] The macro and microstructure of the 120x850x3500mm forging blank prepared in Example 1 and the 200x900x2500mm forging blank prepared in Example 2 were observed, and the corresponding results are shown in Figs. 3-5 and 6-8, respectively. Figures 2-3 Figure 2 4 It can be seen from Figs. 3-5 and 6-8 that the macrostructure of the forging blank head, middle and tail prepared in Examples 1 and 2 is uniform and no visible defects such as stratification and segregation are observed, which meets the 3-5 level of the 11-CL-045D standard. Figure 3 5 It can be seen from Figs. 3-5 and 6-8 that the microstructure of the forging blank head, middle and tail prepared in Examples 1 and 2 is uniform and no visible defects such as stratification and segregation are observed, which meets the 3-5 level of the 11-CL-045D standard.

[0063] Two, mechanical property analysis

[0064] The 80mm long performance sample of the 120x850x3500mm forging blank prepared in Example 1 and the 200x900x2500mm forging blank prepared in Example 2 was taken at the head, middle and tail positions, and then was treated at 840℃ for 2h and air cooled, and the mechanical properties were tested, and the results are shown in Table 1 (the longitudinal mechanical property data of the forging blank prepared in Example 1 after heat treatment) and Table 2 (the longitudinal mechanical property data of the forging blank prepared in Example 2 after heat treatment) as follows:

[0065] Table 1

[0066]

[0067] Table 2

[0068]

[0069] It can be seen from the data in Tables 1 and 2 that the difference between the various mechanical properties such as room tension, impact, high tension and endurance of the forging blank prepared in Examples 1 and 2 at different positions is small, which fully shows that the forging blank uniformity is good.

[0070] Three, ultrasonic flaw detection result analysis

[0071] The water immersion flaw detection of the 120x850x3500mm forging blank prepared in Example 1 and the 200x900x2500mm forging blank prepared in Example 2 was detected, and the forging blank flaw detection at different positions was uniform, reaching the level of Φ1.2-9dB or more.

[0072] ​​​In summary, the TA15 titanium alloy large-size flat plate forging blank prepared by the process has good mechanical properties, the longitudinal room temperature tensile strength is greater than 950MPa, the yield strength is greater than 870MPa, and the longitudinal impact is greater than 45J / cm 2 , the flaw detection level reaches more than Φ1.2-9dB, meanwhile, the macrostructure of the forging blank at different positions is uniform and blurred, the primary alpha in the high-magnification structure is well equiaxed, and the content is 30% to 65%, which fully meets the demand of the aerospace field for the large-size titanium alloy flat plate forging blank with uniform structure and performance.

[0073] The above description is merely a specific implementation of the present application, which enables those skilled in the art to understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application.

[0074] It should be understood that the present application is not limited to the above-described and described, and various modifications and changes can be made without departing from the scope thereof. The scope of the present application is limited only by the appended claims.

Claims

1. A preparation method of a TA15 titanium alloy large-size flat plate forging billet, raw material of the TA15 titanium alloy large-size flat plate forging billet is selected a TA15 titanium alloy ingot with a capacity of 4-10 tons, a size of Φ720mm-Φ1020mm and a chemical composition meeting the standard requirements of 11-CL-045D, characterized in that, The preparation method comprises the following steps: Step 1, open forging The ingot is heated and kept, and is subjected to 2 heating and upsetting and elongating above the phase transition point, and the upsetting and elongating ratio is controlled to be between 1.1 and 2.2 in each heating and upsetting and elongating, and the blank is cooled in air after forging, to obtain an intermediate blank; Step 2, intermediate forging The intermediate blank obtained in step 1 is heated to 60 DEG C below the phase transition point to 100 DEG C above the phase transition point and kept, and is subjected to 4-8 heating and forging, the upsetting and elongating ratio is controlled to be between 1.1 and 2.0 in each heating and upsetting and elongating, and the final forging temperature is not lower than 650 DEG C, and the blank is air-cooled after each forging, to obtain a forged blank; The specific process of the 4-8 heating and forging in step 2 is as follows: The first heating temperature is 20-60 DEG C below the phase transition point, and after keeping for 400-700 min, upsetting and elongating are carried out; The second heating temperature is 20-100 DEG C above the phase transition point, and after keeping for 300-500 min, upsetting and elongating are carried out; The third to eighth heating temperatures are all 20-60 DEG C below the phase transition point, and after keeping for 400-700 min, "reversing upsetting and elongating" forging is carried out, that is, after axial upsetting, radial elongating is carried out, and then after upsetting, axial elongating is carried out again; Step 3, forming forging The forged blank obtained in step 2 is heated to 20-60 DEG C below the phase transition point and subjected to forming forging, the forming forging is completed by 3 heating and elongating, and the final forging temperature is not lower than 650 DEG C in each heating, and the forged blank is air-cooled after forging, to obtain a large-size flat plate forged blank of target size after machining; In the forming forging in step 3, large deformation is used to improve the core structure in the large thickness and low resistance stage, and small deformation is used to eliminate the near-surface deformation dead zone in the small thickness and high resistance stage, and the deformation amounts of the 3 heating and elongating are respectively 30%+ / -10%, 20%+ / -8% and 10%+ / -5%; In the forming forging in step 3, the feeding amount adopts "small feeding, high frequency" elongating technology, and the feeding amounts of the 3 heating and elongating are respectively 150-200 mm, 100-180 mm and 50-120 mm, and the frequency of the press elongating is 30-70 times per minute.

2. The method of producing a TA15 titanium alloy large-size plate forging blank according to claim 1, characterized in that, The specific process of the open forging in step 1 is as follows: first, the ingot is heated to 100-200 DEG C above the phase transition point and kept for 400-700 min, and then is subjected to one heating and upsetting and elongating, and then is reheated to 20-150 DEG C above the phase transition point and kept for 30-180 min, and then is subjected to one heating and upsetting and elongating, and the final forging temperature is not lower than 700 DEG C, and the blank is air-cooled after forging, to obtain an intermediate blank.

3. The method of producing a TA15 titanium alloy large-size plate forging blank according to claim 1, characterized in that, The specific process of the forming forging in step 3 is as follows: The first heating temperature is 20-60℃ below the phase transition point, and after holding for 400-700 minutes, the elongation deformation is carried out; the second heating temperature is 20-60℃ below the phase transition point, and after holding for 250-600 minutes, the elongation deformation is carried out again; the third heating temperature is 20-60℃ below the phase transition point, and after holding for 100-500 minutes, the final elongation deformation is carried out.

4. The method of producing a TA15 titanium alloy large-size plate forging blank according to any one of claims 1 to 3, characterized in that, The preparation method is used for producing TA15 titanium alloy large-size flat forging billets with a thickness of 80mm-300mm, a width of 700mm-1700mm and a length of 1400mm-3500mm, and the flat forging billets have a longitudinal room temperature tensile strength greater than 950MPa, a yield strength greater than 870MPa and a longitudinal impact greater than 45J / cm 2 , and a flaw detection level of Φ1.2-9dB or more.

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