A preparation method for a large-sized β-forged titanium alloy integral blisk forging

Abstract

A preparation method for a large-sized β-forged titanium alloy integral blisk forging, including the process of designing a pre-forged blank, manufacturing a pre-forging die, and forging the blisk forging. The pre-forged blank is designed with concentric circular ring grooves and bosses; the process of forging the blisk forging includes heating the bar stock to 60-80°C below the β phase transformation point; forging the bar stock at a deformation rate of 10-30 mm / s to obtain the pre-forged blank; finishing the pre-forged blank after water cooling; heating the pre-forged blank to 30-40°C above the β phase transformation point; forging the pre-forged blank at a deformation rate of 0.1-0.5 mm / s to obtain the forging; and cooling the forging by exposing it to air. Through the surface structure with grooves and bosses, the present invention enables the metal that originally extends in a single direction during the forging process of the large-sized integral blisk forging to undergo misaligned flow, thereby changing the grain orientation, reducing the size of the texture macro-region, and reducing the atomic diffusion ability in the pre-forging stage by means of low-temperature deformation during the manufacturing of the pre-forged blank and water cooling after forging, achieving the effect of inhibiting grain growth and improving the flaw detection index.

Description

Technical Field

[0001] The present invention relates to the field of metallurgical technology, particularly to the processing of titanium alloys, and especially to a method for preparing a large-sized β-forged integral bladed disk forging of titanium alloy. Background Art

[0002] Due to its high specific strength, good corrosion resistance, non-magnetism, good welding performance, and multiple advantages such as superconductivity, hydrogen storage, and memory, titanium alloys are widely used in frontier fields such as aerospace and military industries. Especially in the aerospace field, the application of titanium alloy forgings is particularly prominent and is usually used to manufacture various key components.

[0003] With the development of a new generation of fighter jets and large aircraft, in order to reduce the number of parts and the additional mass caused by the connection between parts, avoid stress concentration at the joints of components caused by connection, thereby improving the safety and reliability of the aircraft and its engine, reducing the structural weight, and increasing the service life, thus large-scale and integralization have become an important research direction for titanium alloy forgings. The integral bladed disk is a typical lightweight and efficient structure of the compressor system of an advanced aeroengine. It makes the blades and the hub into an integral whole, having the advantages of light weight and avoiding the loss of airflow at the tenons, and can significantly improve the thrust-to-weight ratio and fuel efficiency of the engine.

[0004] β forging is to heat and forge a titanium alloy billet at a temperature above the β phase transformation point. This forging method can significantly reduce the deformation resistance of the metal, improve the process plasticity, thereby reducing costs, and at the same time can significantly improve the creep strength and fracture toughness, and reduce the fatigue crack growth rate. It has become an important production method for titanium alloy forgings and is used for the forging of disks in aeroengines.

[0005] The existing large-sized β-forged integral bladed disk forgings are manufactured by isothermal die forging. First, the bar is heated to 30 - 40°C below the β phase transformation point and forged into a round pre-forged blank by flat die forging. Then, the pre-forged blank is heated to 30 - 40°C above the β phase transformation point, put into the die, and forged into a forging by forming forging. The deformation rate in both two heat treatments is about 1 mm / s. Although the existing process scheme can manufacture products with high strength and high toughness, there is a phenomenon that larger-sized texture macro-regions are formed by grains with the same or approximate orientation, resulting in technical problems of large bottom wave changes and high clutter levels in ultrasonic testing. Summary of the Invention

[0006] The purpose of the present invention is to provide a method for preparing a large-sized β-forged integral bladed disk forging of titanium alloy, and the method for preparing the large-sized β-forged integral bladed disk forging of titanium alloy is to solve the technical problem of larger-sized texture macro-regions formed by grains in the bladed disk forging in the prior art.

[0007] The preparation method of such a large-sized β-forged titanium alloy integral blisk forging of the present invention includes a process of designing a pre-forged blank and preparing a pre-forging die, and a process of forging the blisk forging.

[0008] The process of designing the pre-forged blank and preparing the pre-forging die includes the following steps:

[0009] Step D1: Design the outer shape of the pre-forged blank as a cylinder. The pre-forged blank is the raw material for manufacturing the forging, and the forging is the finished product of the titanium alloy integral blisk forging. Design a plurality of annular grooves at the metal extension position of one end face of the pre-forged blank, and the plurality of grooves are distributed in concentric circles;

[0010] Step D2: Design a plurality of annular bosses on the other end face of the pre-forged blank. The number of the bosses is the same as the number of the grooves, and the positions of the bosses and the grooves are arranged oppositely;

[0011] Step D3: Design and prepare a pre-forging die adapted to the pre-forged blank designed in Steps D1 - D2;

[0012] The process of forging the blisk forging includes the following steps:

[0013] Step S1: Cut the bar stock into a billet, and heat the billet and the pre-forging die described in Step D3 to 60 - 80°C below the β phase transition point and hold for heat preservation;

[0014] Step S2: Put the billet processed in Step S1 into the pre-forging die, and forge it at a deformation rate of 10 - 30 mm / s to obtain a pre-forged blank;

[0015] Step S3: Take out the pre-forged blank obtained in Step S2 from the pre-forging die, and cool it in water to room temperature;

[0016] Step S4: Clean and finish the pre-forged blank after water cooling in Step S3;

[0017] Step S5: Heat the pre-forged blank finished in Step S4 to 30 - 40°C above the β phase transition point and hold for heat preservation, and heat the final forging die to 30 - 50°C below the β phase transition point and hold for heat preservation;

[0018] Step S6: Put the pre-forged blank processed in Step S5 into the final forging die, and forge it at a deformation rate of 0.1 - 0.5 mm / s to obtain a forging;

[0019] Step S7: Take out the forging obtained in Step S6 from the final forging die, and cool it in the air to room temperature.

[0020] Further, in the step D1, the diameter of the pre-forged blank is reduced by 2 - 10 mm compared to the maximum diameter of the forging. The maximum radial width of the groove and the distance between any two adjacent grooves are both 1 / 10 - 1 / 20 of the maximum extension distance of the pre-forged blank. The depth of the groove is 40 - 70% of the height of the pre-forged blank. A first draft angle of 3 - 10° is designed on the inner and outer side walls of the groove.

[0021] In the step D2, the maximum width of the convex platform is the same as the maximum width of the groove. A second draft angle of 3 - 10° is set on the inner and outer side walls of the convex platform. The calculation method for the height of any one convex platform includes a process of calculating the material mass in the first cylindrical ring region of the pre-forged blank and a process of calculating the material mass in the second cylindrical ring region of the forging.

[0022] The process of calculating the material mass in the first cylindrical ring region of the pre-forged blank is as follows:

[0023] Divide a first annular cylinder region on the pre-forged blank. The major diameter of the first cylindrical ring region is equal to the major diameter of the convex platform, and the minor diameter of the first cylindrical ring region is equal to the minor diameter of the convex platform. Calculate the material mass in the first cylindrical ring region. The calculation formula is:

[0024] m1 = m 环 -m 槽 = V 环 × ρ - V 槽 × ρ

[0025] = π × (R 2 - r 2 ) × H × ρ - (V 槽圆台1 - V 槽圆台2 ) × ρ

[0026] = π × (R 2 - r 2 ) × H × ρ - {1 / 3 × π × h 槽 × [R 2 + (R - h 槽 × tanθ1) 2 + R × (R - h 槽 × tanθ1)]} × ρ

[0027] - 1 / 3 × π × h 槽 × [r 2 + (r + h 槽 × tanθ1) 2 + r × (r + h 槽 × tanθ1)]} × ρ

[0028] Wherein, m1 is the material mass in the first annular cylinder region, m 环is the material mass, m, of the first annular cylinder region in the annular cylinder of the pre-forged blank 槽 is the removed material mass of the groove part, m1, m 环 、m 槽 The unit of which is kg,

[0029] H is the height of the pre-forged blank, h 槽 is the depth of the groove, R is the maximum outer radius of the groove, r is the minimum inner radius of the groove, H, h 槽 、R、r are in the unit of mm,

[0030] V 槽圆台1 is the frustum volume formed by the outer side of the groove, V 槽圆台2 is the frustum volume formed by the inner side of the groove, V 槽圆台1 、V 槽圆台2 The unit of which is mm 3 ,

[0031] θ1 is the first draft angle,

[0032] ρ is the density of the titanium alloy, the unit of ρ is kg / mm 3 ;

[0033] The process of calculating the material mass in the second annular cylinder region of the forging is as follows:

[0034] Divide a second annular cylinder region on the forging. The major diameter of the second annular cylinder region is equal to that of the first annular cylinder region, and the minor diameter of the second annular cylinder region is equal to that of the first annular cylinder region, and calculate the material mass of the second annular cylinder region;

[0035] Then calculate the difference between the material mass of the second annular cylinder region and the corresponding material mass of the first annular cylinder region, set the material mass of the boss according to ±5% of the difference, and calculate the volume of the boss according to the material mass and density of the boss. The calculation formula is:

[0036] V 台 =m 台 / ρ

[0037] Among them, V 台 is the volume of the boss, V 台 The unit of which is mm 3 ,

[0038] m 台 is the material mass of the boss, m 台 The unit of which is kg,

[0039] ρ is the density of the titanium alloy, the unit of ρ is kg / mm 3 ;

[0040] Then, the height h of the boss is calculated according to the volume formula of the boss, and the calculation formula is:

[0041] V 台 =V 凸圆台1 -V 凸圆台2

[0042] V 台 =1 / 3×π×h×[R 2 +(R - h×tanθ2) 2 +R×(R - h×tanθ2)]

[0043] -1 / 3×π×h×[r 2 +(r + h×tanθ2) 2 + r×(r + h×tanθ2)];

[0044] Among them, h is the height of the boss, R is the maximum outer radius of the groove, r is the minimum inner radius of the groove, and the units of h, R, and r are mm.

[0045] θ2 is the second draft angle.

[0046] V 台 is the volume of the boss, V 凸圆台1 is the volume of the frustum formed by the outer side of the boss, V 凸圆台2 is the volume of the frustum formed by the inner side of the boss, V 台 、V 凸圆台1 、V 凸圆台2 The units of 、V 3 ;

[0047] And the ratio of the height to the width diameter of any boss is less than or equal to 3:1, and the calculation formula is:

[0048] h / L ≤ 3;

[0049] Among them, h is the height of the boss, L is the width of the boss, and the units of h and L are mm.

[0050] Furthermore, in the step D2, transition fillets with a radius of R5 - 10 mm are provided at the edges of the grooves and bosses of the pre-forged blank.

[0051] Furthermore, in the step D1, a third draft angle of 3 - 5° is provided on the side surface of the pre-forged blank.

[0052] Furthermore, the pre-forging die in the step D3 includes a pre-forging upper die and a pre-forging lower die, and the parting position of the pre-forging upper die and the pre-forging lower die is the edge of the cylindrical surface of the pre-forged blank.

[0053] Furthermore, in the step S2, the load during the forming process of the pre-forged blank is 50 - 95 MN.

[0054] Further, in step S3, the time for taking out the pre-forged blank and immersing it in water is ≤1 min, and the water temperature is 20-45 °C.

[0055] Further, in step S6, the load during the forming process of the large titanium alloy integral bladed disk forging is 60-120 MN.

[0056] The pre-forged blank in the present invention has a profile with concentric circular grooves and bosses, which can control the grain orientation during the forging process to reduce the size of the texture macro-region. The principle is that the grain orientation during the hot deformation process is mainly determined by the metal flow direction. A single-direction continuous long extension distance is likely to lead to the phenomenon of concentrated distribution of grains with the same orientation or approximate orientation. The concave-convex profile structure causes the metal that originally extended in a single direction during the forging process of the large integral bladed disk forging to flow out of position, thereby changing the grain orientation and reducing the size of the texture macro-region.

[0057] The present invention describes a process of manufacturing a pre-forged blank under the conditions of low temperature and high strain rate, and then manufacturing a forging under the conditions of high temperature and low strain rate, which can inhibit the growth of dynamically recrystallized grains, thereby preventing the occurrence of a large texture macro-region caused by large grains. The principle is that when dynamic recrystallization occurs in the material, new grains will be generated. Due to the strong atomic diffusion ability at high temperature for a long time, these grains will continue to grow, especially when in the β region, the growth rate is relatively fast. The present invention reduces the atomic diffusion ability at this stage through the low-temperature deformation during the manufacturing process of the pre-forged blank and the water cooling after forging. At the same time, the high strain rate can effectively shorten the growth time of grains in the hot state, thereby achieving the effect of inhibiting the growth of recrystallized grains.

[0058] By reducing the size of the texture macro-region, ultimately, the change in the bottom wave and the clutter level in the ultrasonic testing of the large β-forged titanium alloy integral bladed disk forging are reduced. The principle is that the detection of the change in the bottom wave in ultrasonic flaw detection is carried out by detecting the reflection energy difference in a region, and the generation of clutter is mainly due to phenomena such as scattering and diffraction when it encounters non-uniform media or interfaces during propagation. When a large number of grains with the same orientation or approximate orientation are concentrated and distributed, a texture macro-region with a large size will be formed. The angles formed by it and the incident wave are different, which will cause a difference in reflection energy, and even energy loss and severe attenuation of the bottom wave, which is the main reason for the large change in the bottom wave; the large texture macro-region can also be regarded as a large grain, and the large grain will cause an increase in the scattering of ultrasonic waves, thereby increasing the clutter level of the product.

[0059] Compared with the prior art, the effects of the present invention are positive and obvious. By designing the surface structure of concentric circular grooves and bosses, the metal that originally extended in a single direction during the forging process of the large integral blisk forging undergoes misaligned flow, thereby changing the grain orientation and reducing the size of the texture macrozone. And by means of low-temperature deformation during the manufacture of the pre-forged blank and water cooling after forging, the atomic diffusion ability in the pre-forging stage is reduced. At the same time, the high deformation rate can effectively shorten the growth time of grains in the hot state, thereby achieving the effect of suppressing grain growth, reducing the size of the texture macrozone to ≤20 μm, thereby reducing the bottom wave change in the ultrasonic flaw detection of the large β-forged titanium alloy integral blisk forging to 1 - 1.5 dB, and reducing the clutter level to ≤5%. Description of the Drawings

[0060] Figure 1 is the top view of the large β-forged titanium alloy integral blisk forging of the present invention.

[0061] Figure 2 is the cross-sectional view of the large β-forged titanium alloy integral blisk forging of the present invention.

[0062] Figure 3 is the top view of the pre-forged blank of the present invention.

[0063] Figure 4 is the cross-sectional view of the pre-forged blank of the present invention.

[0064] Figure 5 is the cross-sectional view of the pre-forging die of the present invention.

[0065] Figure 6 is the schematic diagram for calculating the height of the boss of the present invention.

[0066] Reference numerals in the figures: 1, forging; 101, second annular column region; 2, pre-forged blank; 201, groove; 202, boss; 203, first draft angle; 204, second draft angle; 205, transition fillet; 206, third draft angle; 207, first annular column region; 3, pre-forging upper die; 4, pre-forging lower die. Detailed Embodiments

[0067] The present invention will be further described below with reference to the drawings and embodiments, but the present invention is not limited thereto.

[0068] Embodiment 1

[0069] For a certain β-forged titanium alloy integral blisk forging, the outer diameter is Φ980 mm, the maximum thickness is 315 mm, the single-piece weight is 360 kg, the β phase transformation point is 910 °C, the bar material specification used is Φ360 mm, and the density ρ = 4.51×10 -6 kg / mm 3 .

[0070] The process of designing the pre-forging blank and preparing the pre-forging die includes the following steps:

[0071] Step D1: Design a cylindrical pre-forging blank 2 with an outer diameter of Φ970 mm and a thickness H = 110 mm. According to the bar blank specifications, the maximum extension distance of pre-forging is 315 mm. At the extension position on the upper end face of the pre-forging blank 2, increase 3 annular grooves 201 at 1 / 10 of the maximum extension distance. The radial width of each groove 201 and the spacing distance between any two adjacent grooves 201 are both 32 mm. The specific dimensions of the groove 201 are: the inner radius r1 of the first groove = 196 mm, the outer radius R1 = 228 mm, the inner radius r2 of the second groove = 260 mm, the outer radius R2 = 292 mm, the inner radius r3 of the third groove = 324 mm, the outer radius R3 = 356 mm. The depth of the groove 201 is designed as h 槽 = 66 mm according to 60% of the pre-forging blank thickness. Set a first draft angle 203 of θ1 = 5° on the inner and outer walls of the groove 201;

[0072] Step D2: On the other end face of the pre-forging blank 2, increase 3 annular bosses 202 with the same width at the positions where the grooves 201 are located. Set a second draft angle 204 of θ2 = 5° on the inner and outer walls of the bosses. As Figure 6 shown, L is the width of the boss 202 and the groove 201. Calculate the material mass m1 of the first annular cylinder region 207 of the pre-forging blank 2. The calculation method is to first calculate the mass m 环 of the annular cylinder where the groove is located, and then subtract the material mass m 槽 of the groove 201 part to obtain the material mass m1 of the first annular cylinder region 207; The mass m 环 of the annular cylinder where the groove 201 is located is calculated by calculating the volume V 环 according to the volume formula of the annular cylinder and then multiplying by the density ρ of the material to get m1; The material mass m 槽 of the groove 201 part is calculated by the frustum formula. First, calculate the frustum volume V 槽圆台1 formed by the outer wall of the groove 201, and then subtract the frustum volume V 槽圆台2 formed by the inner wall of the groove 201 to obtain the volume V 槽 of the groove 201 part. Multiply the volume V 槽 of the groove 201 part by the density ρ of the groove to get the mass m 槽 of the groove 201 part. Taking the first annular cylinder region 207 as an example, the calculation process is:

[0073] m 环 =V 环 ×ρ

[0074] =π×(R1 2 -r1 2 )×H×ρ

[0075] =π×(228 2 -196 2 )×110×4.51×10 -6

[0076] ≈21.15kg

[0077] m 槽 =V 槽 ×ρ

[0078] =(V 槽圆台1 -V 槽圆台2 )×ρ

[0079] ={1 / 3×π×h 槽 ×[R1 2 +(R1-h 槽 ×tanθ1) 2 +R1×(R1-h 槽 ×tanθ1)]

[0080] -1 / 3×π×h 槽 ×[r1 2 +(r1+h 槽 ×tanθ1) 2 +r1×(r1+h 槽 ×tanθ1)]}×ρ

[0081] ={1 / 3×π×66×[228 2 +(228-66×tan5°) 2 +228×(228-66×tan5°)]

[0082] -1 / 3×π×66×[196 2 +(196+66×tan5°) 2 +196×(196+66×tan5°)]}×4.51×10 -6

[0083] ≈10.4kg

[0084] m1=m 环 -m 槽 =21.15-10.4=10.75kg

[0085] Using the same method as above, the material masses of the other two first annular cylinder regions 207 are calculated. The material masses of the 3 first annular cylinder regions 207 from the inside to the outside along the diameter direction are 10.75 kg, 14 kg, and 17.2 kg respectively;

[0086] Subsequently, calculate the material mass m2 of the second annular cylinder region 101 of the forging 1. From the inside to the outside along the diameter direction, they are 24 kg, 28.9 kg, and 30.6 kg respectively. Calculate the difference in the material mass between the corresponding second annular cylinder region 101 and the first annular cylinder region 207, that is, 24 - 10.75 = 13.25 kg, 28.9 - 14 = 14.9 kg, 30.6 - 17.2 = 13.4 kg. Set the material mass of the boss 202 within the range of ±5% of the difference. The ranges are: 12.59~13.91 kg, 14.155~15.645 kg, 12.73~14.07 kg. Set the boss mass m 台 to 13.1 kg, 14.7 kg, 13.1 kg. According to the boss mass m 台 and density ρ, calculate the volume V 台 of the boss 202. Then, taking the height h of the boss 202 as the unknown, according to the volume V 凸圆台1 of the frustum formed by the outer wall of the boss 202 minus the volume V 凸圆台2 of the frustum formed by the inner wall of the boss 202 to get V 台 expression, establish an equation to solve for the height of the boss 202. Taking the first boss as an example, the calculation process is as follows:

[0087] m 台 / ρ = (V 凸圆台1 - V 凸圆台2 )

[0088] 13.1 / (4.51×10 -6 ) = {1 / 3×π×h×[R1 2 +(R1 - h×tanθ2) 2 + R1×(R1 - h×tanθ2)]

[0089] - 1 / 3×π×h×[r1 2 +(r1 + h×tanθ2) 2 + r1×(r1 + h×tanθ2)]}

[0090] 13.1 / (4.51×10 -6 ) = 1 / 3×π×h×{[228 2 +(228 - h×tan5°) 2 + 228×(228 - h×tan5°)]

[0091] - [196 2 +(196 + h×tan5°) 2 + 196×(196 + h×tan5°)]}

[0092] Solve the equation to get h = 91 mm;

[0093] Using the same method as above, calculate the heights of the other two bosses 202. Finally, the heights of the 3 bosses 202 are calculated to be 91 mm, 74 mm, and 50 mm in sequence. Then, according to the width of 32 mm of the boss 202, calculate the ratio of the height to the width of the boss 202. The results obtained are all less than 3. Therefore, set the heights of the bosses 202 to 91 mm, 74 mm, and 50 mm. If the ratio is greater than 3, then enlarge the width of the boss in step D1 and recalculate the height of the boss;

[0094] Add a transition fillet 205 with R10 at the edges of the groove 201 and the bosses 202 of the pre-forged blank 2;

[0095] Step D3: Design and prepare a pre-forging die adapted to the pre-forged blank designed in steps D1 - D2. The diameter at the parting surface in the cavities of the pre-forging upper die 3 and the pre-forging lower die 4 is Φ970 mm, and the third draft angle 206 is 3°;

[0096] The process of forging the blisk forging includes the following steps:

[0097] Step S1: Cut the titanium alloy bar stock into a billet, heat the billet to 850 °C and hold for 5 hours, and at the same time heat the pre-forging die described in step D4 to 850 °C and hold for 10 hours;

[0098] Step S2: Place the bar stock into the cavity of the pre-forging die, and complete the manufacture of the pre-forged blank with a forging load of 60 MN and a deformation rate of 10 mm / s;

[0099] Step S3: Open the pre-forging die, take out the pre-forged blank 2 and immediately put it into water at 20 °C and cool it to room temperature.

[0100] Step S4: Clean and finish the pre-forged blank 2, specifically clean the flash and surface impurities;

[0101] Step S5: Heat the pre-forged blank 2 to 940 °C and hold for 2.5 hours, and at the same time heat the die used in the finish forging process to 870 °C and hold for 10 hours;

[0102] Step S6: Place the pre-forged blank 2 into the cavity of the finish forging die, and complete the manufacture of the forging 1 with a forging load of 75 MN and a deformation rate of 0.1 mm / s;

[0103] Step S7: Take out the forging 1 from the finish forging die and expose it to the air to cool it to room temperature.

[0104] Example 2

[0105] A certain β-forged titanium alloy integral blisk forging, with an outer diameter of Φ1200mm, a maximum thickness of 276mm, a single-piece weight of 300kg, a β phase transformation point of 900°C, and the bar stock used has a specification of Φ320mm, and a density ρ = 4.51×10 -6 kg / mm 3 .

[0106] The process of designing the pre-forged blank and manufacturing the pre-forged die includes the following steps:

[0107] Step D1: Design a cylindrical pre-forged blank 2 with an outer diameter of Φ1195mm and a thickness H = 53mm. According to the bar blank specification, the maximum extension distance of the pre-forged forging is 437.5mm. At the upper end surface of the extension position of the upper end surface of the pre-forged blank 2, add 5 annular grooves 201. The radial width of each groove 201 and the spacing distance between any two adjacent grooves 201 are both 30mm. The specific dimensions of the groove 201 are: the inner radius r1 of the first groove = 237.5mm, the outer radius R1 = 267.5mm, the inner radius r2 of the second groove = 297.5mm, the outer radius R2 = 327.5mm, the inner radius r3 of the third groove = 357.5mm, the outer radius R3 = 387.5mm, the inner radius r4 of the fourth groove = 417.5mm, the outer radius R4 = 447.5mm, the inner radius r5 of the fifth groove = 477.5mm, the outer radius R5 = 507.5mm. The depth of the groove 201 is designed as h 槽 = 22mm according to 40% of the pre-forged blank thickness, and set a first draft angle 203 of θ1 = 10° on the inner and outer side walls of the groove 201;

[0108] Step D2: On the other end surface of the pre-forged blank 2, add 5 annular bosses 202 with the same width at the positions where the grooves 201 are located. Set a second draft angle 204 of θ2 = 10° on the inner and outer side walls of the bosses, and calculate the material mass m1 of the first annular cylinder region 207 of the pre-forged blank 2. The calculation method is to first calculate the mass m of the annular cylinder where the groove is located 环 , and then subtract the material mass m of the groove 201 part 槽 to obtain the material mass m1 of the first annular cylinder region 207; The mass m of the annular cylinder where the groove 201 is located 环 is calculated by calculating the volume V according to the volume formula of the annular cylinder 环 and then multiplying by the density ρ of the material to get m1; The removed material mass m of the groove 201 part 槽 is calculated according to the frustum formula. First, calculate the frustum volume V formed by the outer side wall of the groove 201 槽圆台1 and then subtract the frustum volume V formed by the inner side wall of the groove 201 槽圆台2Obtain the volume V of the groove 201 part 槽 , multiply the volume V of the groove 201 part 槽 by the density ρ of the groove to obtain the mass m of the removed material in the groove 201 part 槽 , taking the first first annular cylinder region 207 as an example, the calculation process is as follows:

[0109] m 环 = V 环 ×ρ

[0110] = π×(R1 2 - r1 2 )×H×ρ

[0111] = π×(267.5 2 - 237.5 2 )×53×4.51×10 -6

[0112] ≈11.4kg

[0113] m 槽 = V 槽 ×ρ

[0114] = (V 槽圆台1 - V 槽圆台2 )×ρ

[0115] = {1 / 3×π×h 槽 ×[R1 2 + (R1 - h 槽 ×tanθ1) 2 + R1×(R1 - h 槽 ×tanθ1)]

[0116] - 1 / 3×π×h 槽 ×[r1 2 + (r1 + h 槽 ×tanθ1) 2 + r1×(r1 + h 槽 ×tanθ1)]}×ρ

[0117] = {1 / 3×π×22×[267.5 2 + (267.5 - 22×tan10°) 2 + 267.5×(267.5 - 22×tan10°)]

[0118] - 1 / 3×π×22×[237.5 2 + (237.5 + 22×tan10°) 2 + 237.5×(237.5 + 22×tan10°)]}×4.51×10 -6

[0119] ≈4.1 kg

[0120] m1 = m 环 -m 槽 = 11.4 - 4.1 = 7.3 kg

[0121] Using the same method as above, the material masses of the other four first annular cylinder regions 207 are calculated. The material masses of the 5 first annular cylinder regions 207 along the diameter direction from the inside to the outside are 7.3 kg, 9 kg, 10.7 kg, 12.4 kg, and 14.1 kg respectively;

[0122] Subsequently, the material masses of the second annular cylinder regions 101 of the forging 1 are calculated. Along the diameter direction from the inside to the outside, they are 12.1 kg, 13.8 kg, 15 kg, 15.7 kg, and 16 kg respectively. Subsequently, the differences in the material masses between the corresponding second annular cylinder regions 101 and the first annular cylinder regions 207 are calculated, that is, 12.1 - 7.3 = 4.8 kg, 13.8 - 9 = 4.8 kg, 15 - 10.7 = 4.3 kg, 15.7 - 12.4 = 3.3 kg, 16 - 14.1 = 1.9 kg. The material masses of the bosses 202 are set within the range of ±5% of the differences. The ranges are: 4.56~5.04 kg, 4.56~5.04 kg, 4.085~4.515 kg, 3.135~3.465 kg, 1.805~1.995 kg. The boss mass m 台 is set to 4.8 kg, 4.8 kg, 4.3 kg, 3.3 kg, 1.9 kg. According to the boss mass m 台 and density ρ, the volume V of the boss 202 is calculated 台 , and then, taking the height h of the boss 202 as the unknown, according to the volume V of the frustum formed by the outer sidewall of the boss 202 凸圆台1 subtracting the volume V of the frustum formed by the inner sidewall of the boss 202 凸圆台2 to obtain the V 台 expression, and an equation is established to solve for the height of the boss 202. Taking the first boss as an example, the calculation process is as follows:

[0123] m 台 / ρ=(V 凸圆台1 -V 凸圆台2 )

[0124] 13.1 / (4.51×10 -6 )={1 / 3×π×h×[R1 2 +(R1 - h×tanθ2) 2 +R1×(R1 - h×tanθ2)]

[0125] -1 / 3×π×h×[r1 2 +(r1 + h×tanθ2) 2 +r1×(r1 + h×tanθ2)]}

[0126] 13.1 / (4.51×10 -6 ) = 1 / 3×π×h×{[267.5 2 +(267.5 - h×tan10°) 2 +267.5×(267.5 - h×tan10°)]

[0127] -[237.5 2 +(237.5 + h×tan10°) 2 +237.5×(237.5 + h×tan10°)]}

[0128] Solving the equation gives h = 27 mm;

[0129] Using the same method as above, calculate the heights of the other four bosses 202. Finally, the heights of the 5 bosses 202 are calculated to be 27 mm, 21 mm, 15 mm, 10 mm, and 5 mm in sequence. Then, according to the width of 30 mm of the boss 202, calculate the ratio of the height to the width of the boss 202. The results obtained are all less than 3. Therefore, set the heights of the bosses 202 to 27 mm, 21 mm, 15 mm, 10 mm, and 5 mm. If the ratio is greater than 3, then enlarge the width of the boss in step D1 and recalculate the height of the boss;

[0130] Step D3: Design and prepare a pre-forging die adapted to the pre-forging blank designed in steps D1~D2. The diameter at the middle parting of the pre-forging upper die 3 and the pre-forging lower die 4 is Φ1195 mm, and the third draft angle 206 is 5°;

[0131] The process of forging the bladed disk forging includes the following steps:

[0132] Step S1: Cut the titanium alloy bar stock into a bar blank, heat the bar blank to 840 °C and hold for 6 hours, and at the same time heat the pre-forging die described in step D4 to 840 °C and hold for 10 hours;

[0133] Step S2: Place the bar blank into the cavity of the pre-forging die, and complete the manufacture of the pre-forging blank with a forging load of 90 MN and a deformation rate of 10 mm / s;

[0134] Step S3: Open the pre-forging die, take out the pre-forging blank 2 and immediately put it into water at 20 °C to cool to room temperature;

[0135] Step S4: Clean and finish the pre-forging blank 2, specifically clean the flash and surface impurities;

[0136] Step S5: Heat the pre-forged blank 2 to 930°C and hold for 2 hours, while heating the die used in the forming forging process to 860°C and holding for 10 hours;

[0137] Step S6: Place the pre-forged blank 2 into the cavity of the final die, and complete the manufacturing of the forging 1 with a forging load of 115 MN and a deformation rate of 0.1 mm / s;

[0138] Step S7: Take out the forging 1 from the cavity of the final die and expose it to the air to cool to room temperature.

[0139] Comparative Example 1

[0140] A certain β-forged titanium alloy integral blisk forging, with an outer diameter of about Φ980 mm, a maximum thickness of about 315 mm, a single-piece weight of about 360 kg, a β phase transformation point of 910°C, and the bar stock specification of Φ340 mm. The manufacturing method includes the following steps:

[0141] Step S1: Heat the titanium alloy bar stock to 880°C and hold for 5 hours, while heating the flat die to 880°C and holding for 10 hours;

[0142] Step S2: Place the bar stock into the flat die, and complete the manufacturing of the disc-shaped pre-forged blank with a forging load of 45 MN and a deformation rate of 1 mm / s;

[0143] Step S3: Open the die used for pre-forging, take out the pre-forged blank and expose it to the air to cool to room temperature;

[0144] Step S4: Clean and finish the pre-forged blank;

[0145] Step S5: Heat the disc-shaped pre-forged blank to 940°C and hold for 2.5 hours, while heating the die used in the forming forging process to 870°C (the temperature of the used titanium alloy material) and holding for 10 hours;

[0146] Step S6: Place the pre-forged blank into the cavity of the die, and complete the manufacturing of the forging with a forging load of 75 MN and a deformation rate of 1 mm / s;

[0147] Step S7: Open the die, take out the forging and expose it to the air to cool to room temperature.

[0148] Comparative Example 2

[0149] A certain β-forged titanium alloy integral blisk forging, with an outer diameter of about Φ1200 mm, a maximum thickness of about 276 mm, a single-piece weight of about 300 kg, a β phase transformation point of 900°C, and the bar stock specification of Φ320 mm. The manufacturing method includes the following steps:

[0150] Step S1: Heat the titanium alloy bar to 870 °C and hold for 4.5 hours, and at the same time heat the flat die to 870 °C and hold for 10 hours;

[0151] Step S2: Place the bar into the flat die and complete the manufacturing of the disc-shaped pre-forged blank with a forging load of 68 MN and a deformation rate of 1 mm / s;

[0152] Step S3: Open the die used for pre-forging, take out the pre-forged blank and expose it to the air to cool to room temperature;

[0153] Step S4: Clean and finish the pre-forged blank;

[0154] Step S5: Heat the disc-shaped pre-forged blank to 930 °C and hold for 2 hours, and at the same time heat the die used for the forming forging process with the titanium alloy material at 870 °C and hold for 10 hours;

[0155] Step S6: Place the pre-forged blank into the die cavity and complete the manufacturing of the forging with a forging load of 115 MN and a deformation rate of 1 mm / s;

[0156] Step S7: Open the die, take out the forging and expose it to the air to cool to room temperature.

[0157] Table 1 Forging process parameters

[0158]

[0159] Table 2 Analysis and test results

[0160]

[0161] As can be seen from the above examples and comparative examples combined with Table 1, the weights, dimensions, β-phase transformation points of the materials, and the basic process routes of the integral blisks of "Comparative Example 1 and Example 1" and "Comparative Example 2 and Example 2" are exactly the same. However, the pre-forged blanks used in Comparative Example 1 and Comparative Example 2 are disc-shaped, while those in Example 1 and Example 2 are cylindrical pre-forged blank structures with a profiled surface having concentric circular grooves and bosses; during the manufacturing of the pre-forged blanks in Comparative Example 1 and Comparative Example 2, the heating and holding temperature of the bar is 30 °C below the β-phase transformation point, the deformation rate is 1 mm / s, and the cooling method is air cooling, while in Example 1 and Example 2, it is 60 °C below the β-phase transformation point, the deformation rate is 10 mm / s, and the cooling method is water cooling.

[0162] After separately analyzing and testing the forgings manufactured in all comparative examples and examples, the maximum size of the texture macrozone of the forgings manufactured in Comparative Example 1 is about 100 μm, the bottom wave change is about 5 dB, and the measured clutter level is 18% to 21% (Φ1.2 flat-bottomed hole); the maximum size of the texture macrozone of the forgings manufactured in Comparative Example 2 is about 120 μm, the bottom wave change is 5 dB to 6 dB, and the measured clutter level is 20% to 23% (Φ1.2 flat-bottomed hole), while the maximum size of the texture macrozone of the forgings manufactured in Example 1 is 10 μm, the bottom wave change is about 1 dB, and the measured clutter level is 2% to 3% (Φ1.2 flat-bottomed hole); the maximum size of the texture macrozone of the forgings manufactured in Example 2 is about 20 μm, the bottom wave change is 1 dB to 1.5 dB, and the measured clutter level is 2% to 5% (Φ1.2 flat-bottomed hole).

Claims

1. A method for preparing a large-sized β-forged titanium alloy integral blisk forging, characterized in that: It includes a process of designing a pre-forged blank, preparing a pre-forging die, and a process of forging the blisk forging. The process of designing the pre-forged blank and preparing the pre-forging die includes the following steps: Step D1: Design the outer shape of the pre-forged blank as a cylinder. The pre-forged blank is the raw material for manufacturing the forging, and the forging is the finished product of the titanium alloy integral blisk forging. Design a plurality of annular grooves at the metal extension position on one end face of the pre-forged blank. The plurality of grooves are concentrically distributed. Step D2: Design a plurality of annular bosses on the other end face of the pre-forged blank. The number of bosses is the same as the number of grooves, and the positions of the bosses and the grooves are relatively set. Step D3: Design and prepare a pre-forging die adapted to the pre-forged blank designed in Steps D1 - D2. The process of forging the blisk forging includes the following steps: Step S1: Cut the bar stock into a billet, and heat the billet and the pre-forging die described in Step D3 to 60 - 80 °C below the β phase transformation point and hold for heat preservation. Step S2: Put the billet processed in Step S1 into the pre-forging die, and forge it at a deformation rate of 10 - 30 mm / s to obtain a pre-forged blank. Step S3: Take out the pre-forged blank obtained in Step S2 from the pre-forging die and cool it in water to room temperature. Step S4: Clean and finish the pre-forged blank after water cooling in Step S3. Step S5: Heat the pre-forged blank finished in Step S4 to 30 - 40 °C above the β phase transformation point and hold for heat preservation, and heat the final forging die to 30 - 50 °C below the β phase transformation point and hold for heat preservation. Step S6: Put the pre-forged blank processed in Step S5 into the final forging die, and forge it at a deformation rate of 0.1 - 0.5 mm / s to obtain a forging. Step S7: Take out the forging obtained in Step S6 from the final forging die and cool it in the air to room temperature.

2. The preparation method of the large-sized β-forged titanium alloy integral blisk forging as described in claim 1, characterized in that: In Step D1, the diameter of the pre-forged blank is reduced by 2 - 10 mm compared with the maximum diameter of the forging. The maximum radial width of the groove and the interval distance between any two adjacent grooves are both 1 / 10 - 1 / 20 of the maximum extension distance of the pre-forged blank. The depth of the groove is 40 - 70% of the height of the pre-forged blank. Design a first draft angle of 3 - 10° on the inner side wall and the outer side wall of the groove. In Step D2, the maximum width of the boss is the same as the maximum width of the groove. Set a second draft angle of 3 - 10° on the inner side wall and the outer side wall of the boss. The calculation method of the height of any one boss includes a process of calculating the material mass in the first cylindrical region in the pre-forged blank and a process of calculating the material mass in the second cylindrical region in the forging. The process of calculating the material mass in the first cylindrical region in the pre-forged blank is as follows: Divide a first annular cylindrical region in the pre-forged blank. The major diameter of the first cylindrical region is equal to the major diameter of the boss, and the minor diameter of the first cylindrical region is equal to the minor diameter of the boss. Calculate the material mass in the first cylindrical region. The calculation formula is: m1 = m 环 -m 槽 = V 环 × ρ - V 槽 × ρ =π×(R 2 -r 2 )×H×ρ-(V 槽圆台1 -V 槽圆台2 )×ρ =π×(R 2 -r 2 )×H×ρ-{1 / 3×π×h 槽 ×[R 2 +(R-h 槽 ×tanθ1) 2 +R×(R-h 槽 ×tanθ1)] -1 / 3×π×h 槽 ×[r 2 +(r+h 槽 ×tanθ1) 2 +r×(r+h 槽 ×tanθ1)]}×ρ Among them, m1 is the material mass in the first annular cylinder region, m 环 is the material mass of the annular cylinder of the first annular cylinder region in the pre-forged blank, m 槽 is the material mass removed from the groove part. The units of m1, m 环 , and m 槽 are kg. H is the height of the pre-forged blank, h 槽 is the depth of the groove, R is the maximum outer radius of the groove, r is the minimum inner radius of the groove, H, h 槽 , R, r are in the unit of mm V 槽圆台1 is the volume of the frustum formed by the outer sidewall of the groove, V 槽圆台2 is the volume of the frustum formed by the inner sidewall of the groove, V 槽圆台1 and V 槽圆台2 The unit of 3 , θ1 is the first draft angle. ρ is the density of the titanium alloy, and the unit of ρ is kg / mm 3 ; The process of calculating the material mass in the second cylindrical region in the forging is as follows: Divide a second annular cylinder region on the forging. The major diameter of the second annular cylinder region is equal to that of the first annular cylinder region, and the minor diameter of the second annular cylinder region is equal to that of the first annular cylinder region. Calculate the material mass of the second annular cylinder region. Then calculate the difference between the material mass of the second annular cylinder region and the material mass of the corresponding first annular cylinder region. Set the material mass of the boss according to ±5% of the difference. Calculate the volume of the boss based on the material mass and density of the boss. The calculation formula is: V 台 = m 台 / ρ Among them, V 台 is the volume of the boss, and V 台 is in the unit of mm 3 , m 台 is the material mass of the boss, m 台 with the unit of kg, ρ is the density of the titanium alloy, and the unit of ρ is kg / mm 3 ; Then calculate the height h of the boss according to the volume formula of the boss. The calculation formula is: V 台 =V 凸圆台1 -V 凸圆台2 V 台 = 1 / 3 × π × h × [R 2 + (R - h × tan θ2) 2 + R × (R - h × tan θ2)] -1 / 3×π×h×[r 2 +(r + h×tanθ2) 2 + r×(r + h×tanθ2)]; Where h is the height of the boss, R is the maximum outer radius of the groove, r is the minimum inner radius of the groove, and the units of h, R, and r are mm. θ2 is the second draft angle. V 台 is the volume of the boss, V 凸圆台1 is the volume of the frustum formed by the outer sidewall of the boss, V 凸圆台2 is the volume of the frustum formed by the inner sidewall of the boss, V 台 V 凸圆台1 V 凸圆台2 The unit of V 3 ; And the ratio of the height to the width diameter of any boss is less than or equal to 3:

1. The calculation formula is: h / L ≤ 3; Where h is the height of the boss, L is the width of the boss, and the units of h and L are mm.

3. The preparation method of the large-sized β-forged titanium alloy integral blisk forging as described in claim 1, characterized in that: In the step D2, there are transitional fillets with a radius of R5 - 10 mm at the edges of the grooves and bosses of the pre-forged blank.

4. The preparation method of the large-sized β-forged titanium alloy integral blisk as described in claim 1, characterized in that: In the step D1, there is a third draft angle of 3 - 5° on the side surface of the pre-forged blank.

5. The preparation method of the large-sized β-forged titanium alloy integral blisk forging as claimed in claim 1, wherein: The pre-forging die in the step D3 includes a pre-forging upper die and a pre-forging lower die. The parting position of the pre-forging upper die and the pre-forging lower die is the edge of the cylindrical surface of the pre-forged blank.

6. The preparation method of the large-sized β-forged titanium alloy integral blisk forging as described in claim 1, characterized in that: In the step S2, the load during the forming process of the pre-forged blank is 50 - 95 MN.

7. The preparation method of the large-sized β-forged titanium alloy integral blisk forging as described in claim 1, characterized in that: In the step S3, the time for the pre-forged blank to be taken out and put into water ≤ 1 min, and the water temperature is 20 - 45°C.

8. The preparation method of the large-sized β-forged titanium alloy integral blisk forging as described in claim 1, wherein: In the step S6, the load during the forming process of the large titanium alloy integral blisk forging is 60 - 120 MN.

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