Forging method of high-uniformity beta-state titanium alloy stepped forge piece

Abstract

The invention discloses a forging method of a high-uniformity beta-state titanium alloy stepped forge piece. The forging method comprises the steps of cogging forging, first-time static recrystallization homogenization forging, second-time static recrystallization homogenization forging, stepped forge piece two-phase region drawing blank forging, finished product forging and the like. By the adoption of the method, the produced forge piece is of a uniform lamellar structure, the forge piece can obtain high fracture toughness, and the service life of the shaft forge piece can be prolonged.

Description

Technical Field

[0001] The invention relates to the technical field of titanium alloy material processing, and in particular to a forging method for a high-uniform β-state titanium alloy stage forging. Background Art

[0002] Titanium alloys can obtain different organizational states according to their processing technology. For example, more forging and heat treatment below the phase transition point temperature can obtain equiaxed organization, which has better room temperature performance, but poor high temperature durability and creep resistance; forging and heat treatment in the upper half of the phase transition point temperature can obtain dual-state organization, which has better room temperature performance, but faster crack growth rate; deformation near the phase transition point, or heating in the β phase zone, and forging in the two-phase zone can obtain basketweave organization, which has poor plasticity; forging in the upper half of the β phase zone or quasi-β heat treatment can obtain lamellar organization, which has higher fracture toughness and lower fatigue crack growth rate. In order to meet the requirements of high uniformity, large size and long life surface of the new generation of aircraft load-bearing components, the current aircraft materials mostly adopt the technical route of high damage tolerance. The lamellar structure of titanium alloy can meet the damage tolerance design requirements of the new generation of aircraft, but the uniformity of the lamellar structure plays a vital role in the final performance and service life of the forging. If there is partial structural unevenness in the forging, cracks may initiate here, greatly reducing the service life of the forging.

[0003] Most of the titanium alloy step forgings in the prior art have equiaxed structures and cannot meet the current usage requirements. Summary of the invention

[0004] In view of the above-mentioned deficiencies in the prior art, an object of the present invention is to provide a forging method for a high-uniform β-state titanium alloy step forging.

[0005] To achieve the above purpose, the technical solution adopted by the present invention is as follows: A forging method for a high-uniform β-state titanium alloy step forging, characterized in that it comprises the following steps: Step 1: Forging

[0006] The titanium alloy ingot is heated to 1050°C-1150°C, and the billet is subjected to one-time upsetting forging by a fast forging machine to obtain an intermediate forging billet with an octagonal or quadrilateral cross section, and air-cooled after forging; Step 2: First static recrystallization homogenization forging

[0007] The blank obtained in step 1 is heated to 50-80°C below the β phase transformation point temperature, and a fast forging machine is used to perform a reversing upsetting and drawing forging on the blank, wherein the drawing process is a drawing method of directional homogenization deformation; when the temperature of the blank is lower than 650°C during the forging process, the blank is returned to the furnace for heating at 50-80°C below the β phase transformation point temperature, and the heat preservation time is 30-60min; after forging, the blank is returned to the furnace for recrystallization homogenization, and the return furnace temperature is 80-120°C above the β phase transformation point temperature, and after heating, upsetting and drawing forging is performed, and air cooling is performed after forging, and the cross-section of the blank after homogenization is octagonal or quadrilateral; Step 3: Second static recrystallization homogenization forging

[0008] The blank obtained in step 2 is heated to 30-50°C below the β phase transformation point temperature, and a fast forging machine is used to perform a reversing upsetting and drawing forging on the blank, and a directional homogenization deformation drawing method is performed during the drawing process; when the billet temperature is lower than 650°C during the forging process, the billet is returned to the furnace for heating at 30-50°C below the β phase transformation point temperature, and the heat preservation time is 30-60min; after forging, the billet is returned to the furnace for recrystallization and homogenization, and the return temperature is 50-80°C above the β phase transformation point temperature, and after heating, step drawing is performed, air cooling is performed after forging, and each step cross section of the drawn forging billet after homogenization is octagonal; Step 4: Step forging two-phase zone drawing and billet forging

[0009] The intermediate billet obtained in step 3 is heated to 30-80°C below the β phase transformation point temperature, with a heating coefficient of 0.55-0.80min / mm, and multiple fire drawing forging is performed in the two-phase region, with a single fire deformation of 20-40%, to obtain an intermediate billet for step forgings, air-cooled after forging, and the last fire drawing is performed by rolling drawing; Step 5: Finished Forging

[0010] The intermediate billet obtained in step 4 is heated to 20-50°C above the β phase transformation point temperature. This heating is performed in a step-by-step heating manner. After the heating is completed, the billet is forged into a finished product using a precision forging machine. The precision forging machine is used for multiple passes to forge a step forging product. The final forging temperature is 120°C higher than the β phase transformation point temperature.

[0011] Furthermore, in the above step 1, the heating coefficient of the blank forging is 0.50-0.80 min / mm, and the deformation amount of each upsetting and drawing is 30-50%.

[0012] Further, the specific process of the above step 2 is: Carry out in two batches, The first fire is 2 upsetting and 2 drawing, the heating coefficient is 0.55-0.80min / mm, the deformation of a single upsetting is 20-45%, and the material is drawn radially after two upsettings, so that the metal on the end surface of the material is distributed around the billet. At the same time, the drawing process is first drawn along the large surface of the billet, and then the billet is rotated 45° to deform on the edge surface of the billet, and then rotated 45° to deform on the large surface. The above forging method is repeated until the target size is reached. The above directional homogenization deformation drawing method can eliminate the deformation dead zone in the drawing process and achieve the effect of uniform drawing. The cross section of the billet after forging is octagonal or quadrilateral, and it is returned to the furnace after forging. The second fire is 1 upsetting and 1 drawing, the heating coefficient is 0.30-0.55min / mm, the single upsetting deformation is 20-45%, and the billet is air-cooled after forging. The cross-section of the billet is still octagonal or quadrilateral. At this time, the metal on the end face of the material is distributed around the billet.

[0013] Further, the specific process of step 3 is as follows: It is carried out in two batches. The first fire is 2 upsetting and 2 drawing, the heating coefficient is 0.55-0.80min / mm, the deformation of single upsetting is 20~45%, the deformation modes of straight upsetting and straight drawing and side upsetting and axial drawing are adopted in the 2 upsetting respectively, and the drawing is done along the radial direction of the ingot after the 2nd upsetting to transform the original end metal of the material to the original end, and the drawing process also adopts the drawing method of directional homogenization deformation, the cross section after forging is octagonal or quadrilateral, and the forging is returned to the furnace; The second fire is forging with a heating coefficient of 0.30-0.55 min / mm, step forging, forging to two or more steps, and a drawing deformation of 10-50%. Air cooling is performed after forging.

[0014] The specific process of step 4 above is: The billet is forged by drawing in the two-phase zone for 1-5 times, and the drawing method is drawing forging, with a single-fire deformation of 20-40%; the large and small step sizes are interchanged during billet making, and the original large step adopts a large deformation amount, and is forged to the small step of the finished step forging, with a drawing deformation of 35-85%; the small step adopts a small deformation amount and is forged to the large step of the finished step forging, with a drawing deformation of 10-65%, and air cooling after forging.

[0015] The specific process of step 5 above is: The heating is carried out in a step-by-step heating manner, that is, the temperature is kept at 100-150°C below the β phase transformation point temperature, and the holding time after reaching the temperature is 0.55-0.85min / mm. After the holding is completed, the temperature is raised to 70-100°C below the β phase transformation point temperature, and the holding time after reaching the temperature is 0.35-0.55min / mm. After the holding is completed, the temperature is raised to 40-70°C below the β phase transformation point temperature, and the holding time after reaching the temperature is 0.20-0.35min / mm. After the holding is completed, the temperature is raised to 10-40°C below the β phase transformation point temperature, and the holding time after reaching the temperature is 0.10-0.20min / mm. After the holding is completed, it is heated to 20-50°C above the β phase transformation point temperature of the finished product forging temperature, and the holding time after reaching the temperature is 0.30-0.55 min / mm, after heating, the blank is forged into finished product by fine forging machine, the frequency of large step forging of forgings is 150-600 times / min, the total forging deformation is 40-80%, the total number of passes is 3-5 times, the deformation of single pass is 5-30%, and the deformation of the last pass is ≤10%; the frequency of small step forging of forgings is 50-450 times / min, the total forging deformation is 10-60%, the total number of passes is 2-4 times, the deformation of single pass is 5-20%, and the deformation of the last pass is ≤5%, the forging method is reciprocating forging, the billet pulling rate is ≤8m / min, and the final forging temperature is ≥120℃ below the β phase transformation point temperature.

[0016] The forging methods of conventional step forgings are all forging from the initial large step to the final large step, and from the initial small step to the final small step. The cumulative deformation of the small step in this forging method far exceeds the cumulative deformation of the large step, resulting in obvious differences in the organization and performance of the large and small steps. In addition, the small step with a large cumulative deformation may have a fine crystal bright band at low magnification, and the large step with a small deformation may have an uneven organization at low magnification. The present invention adopts a forging method of interchangeable large and small steps in the production process, with large deformation for the large step and small deformation for the small step, which can obtain uniform organization and performance, and can solve the low magnification anomaly of the forging caused by the mismatch of deformation. At the same time, the present invention adopts two static recrystallization forgings to achieve grain refinement, specifically, the reversing forging is adopted below the first phase transformation point to change the end metal to the surface, and the original end metal is transformed to the initial position at the second phase transformation point, and the uniform deformation stretching method is adopted during the drawing. Combining the above two uniform deformation methods, the original billet can achieve a uniform deformation effect and obtain more uniform recrystallized grains. In addition, the present invention starts heating at an initial heating temperature of 100-150°C below the β phase transformation point temperature during the final β forging, and adopts a 5-step heating process, which can greatly reduce the residence time of the billet in the β phase region, avoiding the organizational difference caused by the temperature difference between the inside and outside of the billet during heating in the single-phase region. The temperature field of the billet of the present invention can be heated more evenly; the finished product is forged using a precision forging machine, and the total deformation, single-pass deformation, forging frequency, and final forging temperature of each step forging are designed according to the step morphology and organizational evolution law, ensuring that the deformation state of the forging process remains consistent during the forging process of each step, and obtaining a uniform lamellar structure.

[0017] The beneficial effects of the present invention are as follows: By adopting the method of the present invention, the forgings produced are of uniform lamellar structure, the forgings can obtain higher fracture toughness, and the service life of the shaft forgings can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 The microstructures at various positions of the Ti-1300 alloy step forging according to the first embodiment of the present invention, wherein a is a large step microstructure and b is a small step microstructure; Figure 2 The microstructures at various positions of the Ti-1050 alloy step forging according to the second embodiment of the present invention, wherein a is a large step microstructure and b is a small step microstructure. DETAILED DESCRIPTION

[0019] The present invention is further described with reference to the specific embodiments of the accompanying drawings and tables. The following are only preferred embodiments of the present invention and are not intended to be used to describe the protection scope of the present invention. Any identical or similar schemes that do not deviate from the previous concept of the present invention should fall within the protection scope of the present invention. In the following text, "◇" represents the height of a blank with an octagonal cross section, and "Φ" represents the diameter of a blank with a circular cross section.

[0020] Example 1 (Preparation of Ti-1300 alloy step forgings)

[0021] The raw material in this example is Ti-1300 Φ680 mm alloy ingot, the ingot β phase transition temperature is 820°C, and the specific forging process is as follows: ① Open forging: heat the ingot to 1150℃, with a heat preservation coefficient of 0.65min / mm. After the heat preservation, the ingot is forged on a fast forging machine with 2 upsettings and 2 drawing. The first drawing is done by diagonal drawing, and the second drawing is done by forging the billet into a square billet of ◇550mm. Air cooling is performed after forging. ② The first static recrystallization homogenization forging, the billet material is heated to 760℃, the heating coefficient is 0.7min / mm, and after the insulation is completed, 2 upsetting and 2 drawing forging is performed on the fast forging machine. This process adopts reversing upsetting and drawing, and the material end metal is distributed around the billet. The two upsettings adopt the deformation methods of straight upsetting and straight drawing and side upsetting and axial drawing respectively. After the second upsetting, the drawing is extended along the radial direction of the ingot, and the original end metal of the material is changed to the original end. When drawing, the large surface of the billet is deformed first, and then rotated 45° on the edge of the billet. Deform, then rotate 45° to deform on the large surface, repeat the forging process (first deform on the large surface of the billet during drawing, then rotate 45° to deform on the edge of the billet, then rotate 45° to deform on the large surface), rotate 24 times in total, forge to ◇550mm square billet, return to 910℃ heating furnace immediately after forging, insulation coefficient 0.50min / mm, perform 1 upsetting and 1 drawing after insulation, forge to ◇550mm square billet, draw along the radial direction during drawing, the metal on the end surface of the material is still distributed around the billet, air cool after forging; ③ The second static recrystallization homogenization forging, the material is heated to 780℃, the heating coefficient is 0.7min / mm, and after the insulation is completed, 2 upsetting and 2 drawing forging is carried out on the fast forging machine. This process adopts reversing upsetting and drawing. The two upsettings adopt the deformation methods of straight upsetting and straight drawing and side upsetting and axial drawing respectively. After the second upsetting, the material is drawn along the radial direction of the ingot to transform the original end metal of the material to the original end. When drawing, the large surface of the billet is deformed first, and then rotated 45° to deform on the edge of the billet. Then rotate 45° to deform on the large surface, and repeat the above forging process (when drawing, first deform on the large surface of the billet, then rotate 45° to deform on the edge of the billet, and then rotate 45° to deform on the large surface), rotate 24 times in total, forge to ◇550mm square billet, and immediately return to the 880℃ heating furnace after forging, with a thermal insulation coefficient of 0.55min / mm. After the thermal insulation is completed, step forging is carried out, the first step forging is to ◇500mm, and the second step forging is to ◇440mm; ④ Two-phase zone billet forging, heating the material to 780℃, insulation coefficient 0.7min / mm, after the insulation is completed, the step forging billet is made on the fast forging machine, the first step forging is forged to Φ250mm, the second step forging is forged to Φ380mm, and air cooling is performed after forging; ⑤ Finished product forging, heat the material to 720℃, insulation coefficient 0.60min / mm, after insulation is completed, heat it to 750℃, insulation coefficient 0.45min / mm, after insulation is completed, heat it to 780℃, insulation coefficient 0.30min / mm, after insulation is completed, heat it to 810℃, insulation coefficient 0.20min / mm, after insulation, heat the finished product forging to 850℃, insulation coefficient 0.40min / mm, after insulation is completed, forge the finished product on the precision forging machine, the first level small step forging to Φ200mm, forging frequency 100 times / min, 2 passes to complete forging, the second level large step forging to Φ260mm, forging frequency 180 times / min, 4 passes to complete forging, the pulling rate during forging is 5mm / min, and air cooling is performed after forging.

[0022] The microstructures of the step forgings prepared in this embodiment at various positions are as follows: Figure 1 As shown, the size ladder structure of the forging is a uniform lamellar structure. The comparison of fracture toughness under different organizational states is shown in Table 1: .

[0023] Example 2 (Preparation of Ti-1050 alloy step forgings)

[0024] The raw material in this example is Ti-1050Φ780mm alloy ingot, the ingot β phase transition temperature is 950℃, and the specific forging process is as follows: ① Open forging: heat the ingot to 1150℃, with a heat preservation coefficient of 0.7min / mm. After the heat preservation, perform 2 upsetting and 3 drawing forging on a fast forging machine. The first and second drawing are done by diagonal drawing. The third drawing is done to forge the billet into a square billet of ◇350mm. Air cooling is performed after forging. ② The first static recrystallization homogenization forging, the billet material is heated to 900℃, the heating coefficient is 0.65min / mm, and after the insulation is completed, 2 upsetting and 2 drawing forging is performed on the fast forging machine. This process adopts reversing upsetting and drawing, and the material end metal is distributed around the billet. The two upsettings adopt the deformation methods of straight upsetting and straight drawing, and side upsetting and axial drawing respectively. After the second upsetting, the drawing is extended along the radial direction of the ingot, and the original end metal of the material is changed to the original end. When drawing, the large surface of the billet is deformed first, and then rotated 45° on the edge of the billet. Deform, then rotate 45° to deform on the large surface, and repeat the forging process (when drawing, first deform on the large surface of the billet, then rotate 45° to deform on the edge of the billet, and then rotate 45° to deform on the large surface), rotate 16 times in total, forge to ◇350mm square billet, and immediately return to the 1050℃ heating furnace after forging, with a thermal insulation coefficient of 0.50min / mm. After the thermal insulation is completed, perform 1 upsetting and 1 drawing, forging to ◇350mm square billet, and draw along the radial direction during drawing, and the metal on the end surface of the material is still distributed around the billet, and air cooling after forging; ③ The second static recrystallization homogenization forging, the material is heated to 920℃, the heating coefficient is 0.65min / mm, and after the insulation is completed, it is forged by 2 upsetting and 2 drawing on the fast forging machine. This process adopts reversing upsetting and drawing, and the original end metal of the material is transformed to the original end. The two upsettings adopt the deformation methods of straight upsetting and straight drawing and side upsetting and axial drawing respectively. After the second upsetting, the drawing is stretched along the radial direction of the ingot, and the original end metal of the material is transformed to the original end. When stretching, the large surface of the billet is deformed first, and then rotated 45° Deform on the edge of the billet, then rotate 45° to deform on the large surface, repeat the above forging process (when drawing, first deform on the large surface of the billet, then rotate 45° to deform on the edge of the billet, then rotate 45° to deform on the large surface), rotate 16 times in total, forge to ◇350mm square billet, immediately return to the 1000℃ heating furnace after forging, insulation coefficient 0.55min / mm, step forging after insulation completion, the first step forging to ◇310mm, the second step forging to ◇280mm; ④ Two-phase zone billet forging, heating the material to 915℃, insulation coefficient 0.65min / mm, after the insulation is completed, the step forging billet is made on the fast forging machine, the first step forging is forged to Φ200mm, the second step forging is forged to Φ255mm, and air cooling is performed after forging; ⑤ Finished product forging, heat the material to 850℃, insulation coefficient 0.55min / mm, after insulation is completed, heat it to 880℃, insulation coefficient 0.40min / mm, after insulation is completed, heat it to 910℃, insulation coefficient 0.25min / mm, after insulation is completed, heat it to 940℃, insulation coefficient 0.15min / mm, after insulation, heat the finished product forging to 980℃, insulation coefficient 0.35min / mm, after insulation is completed, forge the finished product on the fine forging machine, the first level small step forging to Φ150mm, the forging frequency is 400 times / min, and the forging is completed in 3 passes, the second level step forging to Φ180mm, the forging frequency is 300 times / min, and the forging is completed in 3 passes. The pulling rate during forging is 3mm / min, and air cooling is performed after forging.

[0025] The microstructures of the step forgings prepared in this embodiment at various positions are as follows: Figure 2 As shown, the size ladder structure of the forging is a uniform lamellar structure. The comparison of fracture toughness under different organizational states is shown in Table 2: .

Claims

1. A forging method for a high uniform β-state titanium alloy step forging, characterized in that: The steps include: Step 1: Forging The titanium alloy ingot is heated to 1050°C-1150°C, and the billet is subjected to one-time upsetting forging by a fast forging machine to obtain an intermediate forging billet with an octagonal or quadrilateral cross section, and air-cooled after forging; Step 2: First static recrystallization homogenization forging The blank obtained in step 1 is heated to 50-80°C below the β phase transformation point temperature, and a fast forging machine is used to perform a reversing upsetting and drawing forging on the blank, wherein the drawing process is a drawing method of directional homogenization deformation; when the temperature of the blank is lower than 650°C during the forging process, the blank is returned to the furnace for heating at 50-80°C below the β phase transformation point temperature, and the heat preservation time is 30-60min; after forging, the blank is returned to the furnace for recrystallization homogenization, and the return furnace temperature is 80-120°C above the β phase transformation point temperature, and after heating, upsetting and drawing forging is performed, and air cooling is performed after forging, and the cross-section of the blank after homogenization is octagonal or quadrilateral; Step 3: Second static recrystallization homogenization forging The blank obtained in step 2 is heated to 30-50°C below the β phase transformation point temperature, and a fast forging machine is used to perform a reversing upsetting and drawing forging on the blank, and a directional homogenization deformation drawing method is performed during the drawing process; when the billet temperature is lower than 650°C during the forging process, the billet is returned to the furnace for heating at 30-50°C below the β phase transformation point temperature, and the heat preservation time is 30-60min; after forging, the billet is returned to the furnace for recrystallization and homogenization, and the return temperature is 50-80°C above the β phase transformation point temperature, and after heating, step drawing is performed, air cooling is performed after forging, and each step cross section of the drawn forging billet after homogenization is octagonal; Step 4: Step forging two-phase zone drawing and billet forging The intermediate billet obtained in step 3 is heated to 30-80°C below the β phase transformation point temperature, with a heating coefficient of 0.55-0.80min / mm, and multiple fire drawing forging is performed in the two-phase region, with a single fire deformation of 20-40%, to obtain an intermediate billet for step forgings, air-cooled after forging, and the last fire drawing is performed by rolling drawing; Step 5: Finished Forging The intermediate billet obtained in step 4 is heated to 20-50°C above the β phase transformation point temperature. This heating is performed in a step-by-step heating manner. After the heating is completed, the billet is forged into a finished product using a precision forging machine. The precision forging machine is used for multiple passes to forge a step forging product. The final forging temperature is 120°C higher than the β phase transformation point temperature.

2. The forging method of high uniform β titanium alloy step forging according to claim 1, characterized in that: In the above step 1, the heating coefficient of the blank forging is 0.50-0.80min / mm, and the deformation amount of each upsetting and drawing is 30-50%.

3. The forging method of high uniform β-state titanium alloy step forging according to claim 1, characterized in that: The specific process of step 2 above is: Carry out in two batches, The first fire is 2 upsetting and 2 drawing, the heating coefficient is 0.55-0.80min / mm, the deformation of a single upsetting is 20-45%, and the material is drawn radially after two upsettings, so that the metal on the end surface of the material is distributed around the billet. At the same time, the drawing process is first drawn along the large surface of the billet, and then the billet is rotated 45° to deform on the edge surface of the billet, and then rotated 45° to deform on the large surface. The above forging method is repeated until the target size is reached. The above directional homogenization deformation drawing method can eliminate the deformation dead zone in the drawing process and achieve the effect of uniform drawing. The cross section of the billet after forging is octagonal or quadrilateral, and it is returned to the furnace after forging. The second fire is 1 upsetting and 1 drawing, the heating coefficient is 0.30-0.55min / mm, the single upsetting deformation is 20-45%, and the billet is air-cooled after forging. The cross-section of the billet is still octagonal or quadrilateral. At this time, the metal on the end face of the material is distributed around the billet.

4. The forging method of high uniform β titanium alloy step forging according to claim 1, characterized in that: The specific process of step 3 above is: Carry out in two batches, The first fire is 2 upsetting and 2 drawing, the heating coefficient is 0.55-0.80min / mm, the deformation of single upsetting is 20~45%, the deformation modes of straight upsetting and straight drawing and side upsetting and axial drawing are adopted in the 2 upsetting respectively, and the drawing is done along the radial direction of the ingot after the 2nd upsetting to transform the original end metal of the material to the original end, and the drawing process also adopts the drawing method of directional homogenization deformation, the cross section after forging is octagonal or quadrilateral, and the forging is returned to the furnace; The second fire is forging with a heating coefficient of 0.30-0.55 min / mm, step forging, forging to two or more steps, and a drawing deformation of 10-50%. Air cooling is performed after forging.

5. The forging method of high uniform β titanium alloy step forging according to claim 1, characterized in that: The specific process of step 4 is as follows: The billet is forged by 1-5 fire drawing in the two-phase zone, and the drawing method is drawing forging, with a single-fire deformation of 20-40%; the large and small step sizes are interchanged during billet making, and the original large step adopts a large deformation amount, and is forged to the small step of the finished step forging, with a drawing deformation of 35~85%; the small step adopts a small deformation amount and is forged to the large step of the finished step forging, with a drawing deformation of 10~65%, and air cooling after forging.

6. The forging method of high uniform β titanium alloy step forging according to claim 1, characterized in that: The specific process of step 5 above is: The heating is carried out in a step-by-step heating manner, that is, the temperature is kept at 100-150°C below the β phase transformation point temperature, and the holding time after reaching the temperature is 0.55-0.85min / mm. After the holding is completed, the temperature is raised to 70-100°C below the β phase transformation point temperature, and the holding time after reaching the temperature is 0.35-0.55min / mm. After the holding is completed, the temperature is raised to 40-70°C below the β phase transformation point temperature, and the holding time after reaching the temperature is 0.20-0.35min / mm. After the holding is completed, the temperature is raised to 10-40°C below the β phase transformation point temperature, and the holding time after reaching the temperature is 0.10-0.20min / mm. After the holding is completed, it is heated to 20-50°C above the β phase transformation point temperature of the finished product forging temperature, and the holding time after reaching the temperature is 0.30-0.55 min / mm, after heating, the blank is forged into finished product by fine forging machine, the frequency of large step forging of forgings is 150-600 times / min, the total forging deformation is 40-80%, the total number of passes is 3-5 times, the deformation of single pass is 5-30%, and the deformation of the last pass is ≤10%; the frequency of small step forging of forgings is 50-450 times / min, the total forging deformation is 10-60%, the total number of passes is 2-4 times, the deformation of single pass is 5-20%, and the deformation of the last pass is ≤5%, the forging method is reciprocating forging, the billet pulling rate is ≤8m / min, and the final forging temperature is ≥120℃ below the β phase transformation point temperature.

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