A hot calibrating die and method for a cambered-titanium-alloy stator inner ring

Abstract

The application discloses a hot calibrating die and method for a cambered generatrix titanium alloy stator inner ring, and belongs to the technical field of sheet metal forming. The hot calibrating die comprises a base, and an adjusting pad is clamped on the base. Alternately arranged fan-shaped expansion petals and equal-width expansion petals are arranged on the adjusting pad. An inner taper ring is arranged on the inner circumferences of the fan-shaped expansion petals and the equal-width expansion petals. The outer circumferences of the fan-shaped expansion petals and the equal-width expansion petals are used for placing a part to be calibrated. An outer heat insulation ring is arranged on the outer circumference of the part to be calibrated. The part to be calibrated is calibrated by the die. The inner taper ring is used for driving the multiple expansion petals to move radially to realize hot calibration. The titanium alloy stator inner ring part with high precision can be processed. The hot calibration of the titanium alloy stator inner ring with the cambered generatrix and the radial deep ring groove structure can be applied. The problem of low forming precision of the compressor stator inner ring of an aero-engine is solved. The development requirements of the cambered generatrix titanium alloy stator inner ring type are ensured.

Description

Technical Field

[0001] This invention belongs to the field of sheet metal forming technology, specifically relating to a hot forming mold and hot forming method for a curved busbar titanium alloy stator inner ring. Background Technology

[0002] The curved generatrix titanium alloy stator inner ring of a turbofan engine is a sheet metal part with poor cold forming performance, making it impossible to form at room temperature and requiring a hot forming process. However, its structure is special, with a curved generatrix, a large taper, an inner ring groove, a centripetal opening, a large radial depth, and an overall ring structure. Therefore, it cannot be directly hot-formed and must be pre-formed and then hot-formed to ensure the required machining accuracy.

[0003] However, the inner ring of the titanium alloy stator of the turbofan engine has high precision requirements (e.g., the curve generatrix). Figure 1 The material is TA1 titanium alloy. The part design requires an end face flatness of 0.2mm, an outer surface circular runout of 0.2mm, and a profile line contour of 0.4mm. For this special structure of high-precision titanium alloy stator inner ring, traditional hot forming processes cannot guarantee the design requirements. First, the outer surface of the part to be formed is in direct contact with air, and the heating and cooling rates are faster than those of the expansion flaps, reducing the stress relaxation effect of the part material at high temperatures. The significant difference in heating and cooling rates between the upper and lower sections of the expansion flaps leads to a large difference in diameter between the upper and lower sections of the part's profile, resulting in low hot forming accuracy. Second, the expansion flaps are all fan-shaped. In order to fit the expansion flaps into the annular groove of the part, the width of the fan-shaped expansion flaps must be reduced. After the bottom surface of the ring groove is fitted, the gap between the expansion petals will become very large. The large gap between the expansion petals cannot allow the surface of the part to be shaped to be fully expanded and supported, so the circular runout requirement of the surface of the part to be shaped cannot be guaranteed. Thirdly, because the actual coefficient of thermal expansion of the part and the mold material to be shaped has some error compared with the coefficient of thermal expansion obtained from the manual, the hot shaped mold must be tested and corrected in the early stage of hot shaped forming. When the diameter of the part surface after hot shaped forming is large, the outer conical surface of the inner conical ring must be machined. The machining and measurement of the conical surface is relatively troublesome and the accuracy is difficult to control. Summary of the Invention

[0004] In order to overcome the shortcomings of the prior art, the purpose of this invention is to provide a hot forming mold and hot forming method for a curved busbar titanium alloy stator inner ring, so as to improve the accuracy of manufacturing compressor stator inner rings for aero engines.

[0005] To achieve the above objectives, the present invention employs the following technical solution:

[0006] This invention discloses a thermal calibration mold for the inner ring of a curved busbar titanium alloy stator, including a base, an adjustment pad snapped onto the base, and alternating fan-shaped expansion petals and equal-width expansion petals on the adjustment pad. An inner conical ring is provided on the inner circumference of the fan-shaped expansion petals and the equal-width expansion petals, and the part to be calibrated is placed on the outer circumference. An outer heat insulation ring is provided on the outer circumference of the part to be calibrated.

[0007] Preferably, the base has inner limit pins evenly distributed on its inner circumference and outer limit pins evenly distributed on its outer circumference, and the adjusting pad is centered by the outer limit pins.

[0008] More preferably, the base has a hollow structure.

[0009] Preferably, a lifting ring is provided between the inner limit pins.

[0010] Preferably, the adjusting pad is a ring structure with a thickness of 15-20 mm.

[0011] Preferably, the fan-shaped expansion valve, the equal-width expansion valve, and the adjusting pad are all made of TA7 material.

[0012] More preferably, the material of the inner conical ring is Cr18Ni12Mo2Ti.

[0013] Preferably, the radial thickness of the fan-shaped expansion lobes and the equal-width expansion lobes is:

[0014]

[0015] Where: R jh —The radius of the theoretical height h point on the inner surface of the part to be corrected, as required by the design drawing; R xh —The radius of the inner conical ring at the theoretical height h; W bh —Radial thickness of the fan-shaped and equal-width expansion lobes at the theoretical height h; α x —The average linear expansion coefficient of the inner cone ring material at the heat-setting temperature T; α b —The average linear expansion coefficient of fan-shaped and equal-width fan-shaped materials at the heat-setting temperature T; α j —The average linear expansion coefficient of the material of the part to be shaped at the hot forming temperature T; ΔT —The temperature difference between the hot forming temperature T and the room temperature.

[0016] Preferably, the semi-cone angle of the outer conical surface of the inner conical ring is θ = 3°.

[0017] This invention also discloses a hot-forming method for a hot-forming mold of a titanium alloy stator inner ring for a curved busbar. First, the base and adjusting pad are placed at the center of the hydraulic press worktable. The part to be shaped is placed on the adjusting pad with its large end facing down, ensuring concentricity between the part and the adjusting pad. Then, fan-shaped expansion flaps are evenly placed circumferentially against the inner surface of the part to be shaped. Next, equal-width expansion flaps are sequentially placed between the fan-shaped expansion flaps and against the inner surface of the part to be shaped. Then, an inner conical ring is installed on the inner circumference of the fan-shaped expansion flaps and the equal-width expansion flaps, and pressure is evenly applied to the upper end face of the inner conical ring to press it to the bottom. Then, an outer heat insulation ring is fitted around the outer circumference of the part to be shaped. The hot-forming mold with the part to be shaped is placed in a heat treatment furnace for hot-forming. After hot-forming, the part is removed from the furnace. Once the surface temperature of the inner conical ring is below 60°C, the part to be shaped is removed, completing the hot-forming process.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] The present invention provides a hot-forming mold for a curved busbar titanium alloy stator inner ring, with improvements mainly in the following aspects:

[0020] 1) The basic structure of an inner conical ring and multiple expansion lobes is adopted. The inner conical ring drives multiple expansion lobes to move radially, thereby achieving thermal correction.

[0021] 2) Adding an external heat insulation ring to the outer surface of the part serves several purposes: first, it limits the upward warping deformation of the small end of the part; second, it shields the part from direct heating, ensuring that the heating and cooling rates of the part are basically consistent with those of the inner conical ring; and third, when approaching the heat-correcting temperature, it can envelop the outer surface of the part to be corrected, constraining the shape of the part and improving the surface accuracy of the part, thereby improving the heat-correcting accuracy and solving the problem of out-of-tolerance line profile caused by the difference in expansion and contraction rates between the large and small ends of the part to be corrected.

[0022] 3) By using alternating fan-shaped expansion flaps and expansion flaps of equal width, the expansion flaps can be smoothly installed into the annular groove of the part without reducing the contact area between the expansion flaps and the part's surface, thereby improving the accuracy of thermal straightening.

[0023] 4) The mold is used to heat-correct the pre-formed semi-finished parts. Before heat correction, a 2-3 mm diameter allowance is reserved to increase the stress relaxation effect.

[0024] Furthermore, the expansion flap material is selected from TA7 material, which has a coefficient of linear expansion very close to that of the part to be calibrated and has high hardness and strength. This allows the expansion flap and the part to expand and contract synchronously in height, so that the height dimension of the preformed part can be processed to the final requirement without leaving any thermal calibration allowance. During the thermal calibration process, the height of the expansion flap and the width of the part groove are always consistent without any gaps. This ensures that the inner surface of the part is fully fitted with the outer surface of the expansion flap throughout the entire height. This solves the problems of warping and collapsing deformation of the small end face of the part and difficulty in controlling the height dimension caused by the different expansion amounts of the expansion flap and the part in height. It can guarantee the height dimension tolerance of the part to be calibrated.

[0025] Furthermore, using Cr18Ni12Mo2Ti as the material for the inner conical ring ensures that the inner conical ring has good thermal strength, thermal stiffness and thermal stability, as well as a large coefficient of linear expansion, providing sufficient expansion stress to the part and ensuring stress relaxation effect.

[0026] Furthermore, a design method for the radial thickness of the expansion flap is given, which can meet the requirements when the expansion flap and the inner conical ring are made of dissimilar materials.

[0027] Furthermore, by setting an adjustment shim under the expansion flap, the thickness of the adjustment shim can be adjusted according to the mold trial results, thereby solving the problem of needing to fine-tune the diameter size after the trial molding, improving the diameter size accuracy of the part to be calibrated, and making mold repair simple and efficient.

[0028] This invention provides a hot forming method for a hot forming mold of a curved busbar titanium alloy stator inner ring. The method employs an inner conical ring driving multiple evenly distributed expansion flaps around the circumference of the part to be formed. Before entering the furnace for hot forming, a hydraulic press is first used to pressurize the upper surface of the inner conical ring, pushing it downwards. The outer conical surface of the inner conical ring then drives the surrounding expansion flaps to move radially outwards. The outer surfaces of the expansion flaps are in close contact with the inner surface of the part to be formed, thus expanding the part. Because the compression amount of the inner conical ring is matched with the diameter of the part to be formed, the expansion amount of the part after the inner conical ring is pressed to the bottom is controlled. This applies an initial expansion force to the part before it enters the furnace for hot forming. During the hot forming process of parts, the outer heat insulation ring can slow down the heating and cooling rate of the parts to be formed, making it close to the heating and cooling rate of the inner conical ring and the expansion valve. This has a good effect on improving the surface accuracy of the parts to be formed after hot forming. The initial expansion force and the thermal expansion force of the inner conical ring and the expansion valve are superimposed, which can increase the expansion force of the parts to be formed at high temperature, improve the stress relaxation effect of the material of the parts to be formed at high temperature, and thus improve the hot forming accuracy of the parts to be formed.

[0029] This technology can solve the problem of low forming accuracy of the inner ring of the stator of the aero-engine compressor, ensuring the requirements of model development. This technology can be extended to the hot forming of sheet metal parts with similar structural features, and can simultaneously control the axial and radial dimensional accuracy to obtain high-quality sheet metal forming parts. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the inner ring structure of the compressor stator of a certain type of aero-engine;

[0031] Figure 2 This is a schematic diagram of the thermal forming mold of the present invention;

[0032] Figure 3 for Figure 2 Top view;

[0033] Figure 4 This is a schematic diagram illustrating the calculation of the radial thickness of the expansion flap in this invention;

[0034] Figure 5 This is a schematic diagram of the part to be calibrated;

[0035] Figure 6 A diagram of the mold base and adjustment pad;

[0036] Figure 7 A diagram for installing the parts to be aligned;

[0037] Figure 8 A diagram for installing the fan-shaped expansion flaps;

[0038] Figure 9 A diagram for installing equal-width expansion flaps;

[0039] Figure 10 A diagram for installing the inner conical ring;

[0040] Figure 11 A diagram for installing the external heat insulation ring;

[0041] Figure 12 Diagram for grinding and adjusting the shims;

[0042] Figure 13 This is a diagram for grinding the inner conical ring.

[0043] Wherein: 1-Outer heat insulation ring; 2-Inner conical ring; 3-Inner limiting pin; 4-Lifting ring; 5-Part to be calibrated; 6-Outer limiting pin; 7-Adjusting pad; 8-Base; 9-Fan-shaped expansion flap; 10-Equal width expansion flap. Detailed Implementation

[0044] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0045] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus. In this invention, the "part to be shaped" is a sheet metal part with a curved generatrix, a semi-cone angle greater than 15°, an inner annular groove, a concentric opening, a radial depth greater than 8 mm, and an overall annular structure.

[0046] The present invention will now be described in further detail with reference to the accompanying drawings:

[0047] This invention provides a hot-forming mold for a curved busbar titanium alloy stator inner ring, see [link to mold]. Figure 2 and Figure 3The system includes a base 8, which has a hollow structure to reduce the weight of the mold. Four inner limit pins 3 and four lifting rings 4 are alternately distributed around the hollow portion. The lifting rings 4 are used to lift and transfer the mold. Four outer limit pins 6 are evenly distributed around the upper outer periphery of the base 8. A ring-shaped adjusting pad 7 with a thickness of 15-20mm is engaged between the inner limit pins 3 and the outer limit pins 6. The adjusting pad 7 is concentric with the base 8, made of TA7 material, and is used to place the part 5 to be shaped and to adjust the mold. An expansion flap is detachably connected to the adjusting pad 7. The outer circumference of the expansion flap is arc-shaped and fits against the inner surface of the part 5 to be shaped. The material of the expansion flap is the same as that of the adjusting pad 7. The expansion flap is obtained by alternating combinations of fan-shaped expansion flaps 9 and equal-width expansion flaps 10. The width of the fan-shaped expansion flap 9 is smaller on the inside and larger on the outside, and the two sides form an angle with the plane of symmetry. The inner and outer widths of the equal-width expansion flap 10 are the same, and the two sides are parallel to the plane of symmetry. The number of fan-shaped expansion flaps 9 and equal-width expansion flaps 10 is preferably 8. Using expansion flaps of different shapes can reduce the gap between the expansion flaps after expansion, increase the contact area between the outer surface of the expansion flap and the inner surface of the part 5 to be shaped, and improve the shaping accuracy. An inner conical ring 2 is snapped into the inner circumference of the expansion flap. The inner hole of the inner conical ring 2 is a conical surface with a half-cone angle of 3° to 5°, and the outer surface is a conical surface with a half-cone angle of θ = 3° to 5°, thereby keeping the radial thickness of the upper and lower ends of the inner conical ring 2 consistent. To reduce the heat capacity of the inner conical ring 2, an annular groove is provided in the inner hole of the inner conical ring 2. The inner conical ring 2 is made of heat-resistant stainless steel material Cr18Ni12Mo2Ti, which has good thermal strength, thermal stiffness, and thermal stability within the heat-correcting temperature range and a large coefficient of linear expansion. The part to be corrected 5 is placed on the outer periphery of the expansion flap. An outer heat insulation ring 1 is detachably connected to the outside of the part to be corrected 5. The inner surface of the outer heat insulation ring 1 is designed according to the maximum solid boundary of the outer surface of the part to be corrected 5, and its radial thickness is 10-15 mm, while the axial thickness is determined according to the height of the part to be corrected 5. The expansion flap and adjusting shim 7 are made of the same material as the outer heat insulation ring 1.

[0048] The design process of the hot forming mold for the inner ring of the titanium alloy stator of the above-mentioned curved busbar is as follows:

[0049] 1) Determination of the outer cone surface radius of the inner cone ring 2

[0050] The hot-forming mold adopts a basic structural form in which an inner conical ring 2 drives the radial movement of multiple expansion flaps. Considering the strength and stiffness of the inner conical ring 2 and the expansion flaps under the high-temperature conditions of hot forming, such as... Figure 4 As shown, a rough value for the radial thickness of the expansion flap is first set, and then the diameter of the inner conical ring 2 is determined based on the expansion flap thickness value. The semi-cone angle of the outer conical surface of the inner conical ring 2 is θ = 3°, so the radius R at each theoretical height h on the outer conical surface of the inner conical ring 2 can be calculated. xh .

[0051] 2) Calculation of radial thickness of the expansion flap

[0052] The radius R of the outer cone surface of the inner cone ring 2 at the theoretical height h was determined. xh Then, at the heat-correcting temperature T, the radial thickness W of the expansion lobe at the theoretical height h can be calculated using formula (1). bh The precise value.

[0053]

[0054] exist Figure 4 And in formula (1):

[0055] R jh —The radius of the theoretical height h point on the inner surface of the part to be corrected, as required by the design drawings;

[0056] R xh —The radius of the inner conical ring at the theoretical height h;

[0057] W bh —Radial thickness of the expansion flap at the theoretical height h;

[0058] α x —The average linear expansion coefficient of the inner cone ring material at the heat-setting temperature T;

[0059] α b —The average linear expansion coefficient of the expansion valve material at the heat-setting temperature T;

[0060] α j —The average coefficient of linear expansion of the material of the part to be shaped at the hot-shaped temperature T;

[0061] ΔT — The temperature difference between the thermoforming temperature T and the room temperature.

[0062] 3) Calculation of the axial dimension of the expansion valve

[0063] At the heat-correcting temperature T, the axial dimension of the expansion flap is calculated according to formula (2).

[0064]

[0065] In formula (2):

[0066] L j —Axial dimensions of the part to be calibrated (including height, groove width, wall thickness, and theoretical point position dimensions of the profile);

[0067] L b —Axial dimension of the expansion flap (the expansion flap dimension corresponding to the axial dimension of the part to be shaped);

[0068] α b —The average linear expansion coefficient of the expansion lobes at the heat-correcting temperature T;

[0069] αj —The average coefficient of linear expansion of the part to be shaped at the heat-forming temperature T;

[0070] ΔT — The temperature difference between the heat-correcting temperature T and the room temperature.

[0071] Since the linear expansion coefficient of the expansion flap is very close to that of the part 5 to be shaped, the calculation result shows that the axial dimension of the expansion flap is very close to the axial dimension of the corresponding part 5 to be shaped.

[0072] 4) Inner dimensions of the outer insulation ring

[0073] The outer heat insulation ring 1 is made of TA7 material, which has a coefficient of linear expansion very close to that of the part 5 to be shaped. Because the coefficients of expansion are basically equal, the outer surface of the part 5 to be shaped and the inner surface of the outer heat insulation ring 1 will theoretically not come into contact during the heating and cooling process, and will only come into contact when the highest temperature for thermal shaping is reached. Therefore, the inner surface dimension of the outer heat insulation ring 1 is designed according to the maximum solid boundary of the outer surface of the part 5 to be shaped.

[0074] If the radial thickness of the outer heat insulation ring 1 is too large, it will prolong the heating and cooling time, leading to a decrease in production efficiency. However, if the thickness is too small, it is prone to deformation. Considering all factors, the radial thickness is set to 10-15 mm. The axial thickness is determined based on the height of the part to be calibrated 5, and the thickness of the small end is appropriately increased to ensure the limiting effect of the small end face of the part to be calibrated 5. In order to reduce the temperature difference between the large and small ends of the part to be calibrated 5, the outer diameter of the small end of the outer heat insulation ring 1 is appropriately increased.

[0075] 5) Adjust the material and thickness of pad 7

[0076] Because the actual linear expansion coefficients of the materials of the inner conical ring 2, the expansion flap, and the part 5 to be shaped all have some errors compared to the calculated values, and the mold components also have manufacturing errors, these errors will affect the thermal shaping accuracy of the part 5 to be shaped. To eliminate these errors and improve the thermal shaping accuracy of the part 5 to be shaped, the mold should be adjusted according to the actual test results of the part 5 to be shaped after the first use. Adding an adjusting shim 7 under the expansion flap makes mold adjustment simple and convenient. To reduce the influence of the thermal expansion factor of the adjusting shim 7, the linear expansion coefficient of the adjusting shim 7 material should be small; therefore, the adjusting shim 7 is selected from the same material TA7 as the expansion flap. Considering the rigidity of the adjusting shim 7 and ease of grinding, the thickness of the adjusting shim 7 is 15–20 mm.

[0077] 6) Hot forming mold

[0078] The hot-forming mold employs an inner conical ring 2 and a multi-flap structure. While ensuring strength and rigidity, the thickness of the inner conical ring 2 and the flaps is minimized to control heating and cooling times. The semi-cone angle of the outer conical surface of the inner conical ring 2 is designed to be 3° to control the difference in expansion between the large and small ends caused by the diameter difference, thus ensuring the linear profile accuracy of the part 5 to be formed. Sixteen flaps are used, controlling the arc length of each flap to distribute circumferential expansion errors and ensure the circular runout accuracy of the part 5 to be formed. Both fan-shaped and equal-width flaps are used to facilitate denser fitting of the flaps, reduce the gap between them, and further improve the circular runout accuracy of the part 5 to be formed.

[0079] Other non-critical elements are designed according to standard procedures. The final thermal forming mold design is as follows: Figure 2 and Figure 3 As shown.

[0080] The present invention provides a method for hot-forming a mold for a curved busbar titanium alloy stator inner ring, comprising the following steps:

[0081] 1. Apply anti-oxidant to parts.

[0082] Clean the surface of part 5 to be shaped. Apply an anti-oxidation emulsifier evenly to the inner and outer surfaces of part 5 and allow it to dry. Figure 5 As shown.

[0083] 2. Clamping parts

[0084] 1) Remove the inner conical ring 2, remove the outer heat insulation ring 1, and remove 8 equal-width expansion lobes 10 and 8 fan-shaped expansion lobes 9.

[0085] 2) Place the mold base 8 and adjusting pad 7 onto the hydraulic press's worktable and adjust them to the center of the worktable, such as... Figure 6 As shown.

[0086] 3) Place the part 5 to be shaped, with its large end facing down, onto the adjusting pad 7 of the hot-forming mold, and visually align it with the adjusting pad 7. Figure 7 As shown.

[0087] 4) Insert 8 fan-shaped expansion petals, evenly distributed circumferentially, and radially attached to the inner surface of the part to be shaped 5, such as... Figure 8 As shown.

[0088] 5) Insert a uniformly wide expansion flap 10 between every two fan-shaped expansion flaps 9, and fit it tightly against the inner surface of the part 5 to be shaped, such as... Figure 9 As shown.

[0089] 6) Move the expansion valves appropriately to ensure that the gap between the expansion valves is uniform.

[0090] 7) Install the inner cone ring 2, as follows: Figure 10 As shown.

[0091] 8) Use a hydraulic press on the worktable to apply pressure evenly to the upper end face of the inner cone ring 2, pressing the inner cone ring 2 to the bottom.

[0092] 9) Install the outer heat insulation ring 1, as follows Figure 11 As shown.

[0093] 3. Thermal calibration

[0094] The mold and the part to be shaped 5 are placed in the heat treatment furnace, heated to 600°C according to the heat shaping system, held for 3 hours, and then cooled to below 300°C before being taken out of the furnace.

[0095] 4. Cooling to room temperature

[0096] The part to be shaped 5, together with the mold, is cooled at room temperature. Only after the surface temperature of the inner cone ring 2 is below 60°C can the part to be shaped 5 be disassembled.

[0097] 5. Disassemble parts

[0098] Remove the inner conical ring 2, radially withdraw the expansion flap, and take out the part 5 to be shaped.

[0099] 6. Clean the antioxidant

[0100] Use clean water to clean the anti-oxidant on the inner and outer surfaces of the part to be shaped 5, and then wipe or blow dry.

[0101] 7. Inspection

[0102] Measure the average diameter at each measuring point on the outer surface, and calculate the difference between the measured value and the theoretical value, ±ΔΦ. If the average diameter exceeds the tolerance, the mold should be adjusted according to the following method.

[0103] 8. Trim the mold

[0104] This process is only used when mold repair is required. If the average diameter is greater than the required value, the upper end face of the adjusting shim should be ground. Figure 12 As shown, the amount of grinding is:

[0105] Δt=ΔΦ / 2 / tanθ

[0106] After the mold is repaired, a hot forming test must be conducted again to verify that the mold size can guarantee the diameter requirement of the part to be formed. Only then can the mold be used for mass production.

[0107] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A hot calibrating die for a cambered titanium alloy stator inner ring, characterized in that, The base (8) is provided with the adjusting pad (7) clamped thereon, the adjusting pad (7) is provided alternately with the fan-shaped expansion petals (9) and the equal-width expansion petals (10), the width of the fan-shaped expansion petals (9) is small inside and large outside, and the two side surfaces form an included angle with the symmetry surface; the equal-width expansion petals (10) have the same width inside and outside, and the two side surfaces are parallel to the symmetry surface; the fan-shaped expansion petals (9), the equal-width expansion petals (10) and the adjusting pad (7) are all made of TA7 material; the inner circumferences of the fan-shaped expansion petals (9) and the equal-width expansion petals (10) are provided with the inner taper rings (2), the outer circumferences are provided with the parts (5) to be corrected, and the outer circumferences of the parts (5) to be corrected are provided with the outer heat insulation rings (1).

2. The hot calibrating die for the inner ring of the cambered-blade titanium alloy stator static ring according to claim 1, characterized in that, The base (8) is provided with the inner limiting pins (3) uniformly distributed on the inner circumferences and the outer limiting pins (6) uniformly distributed on the outer circumferences, and the adjusting pad (7) is centered by the outer limiting pins (6).

3. The hot calibrating die for the inner ring of the cambered-blade titanium alloy stator static ring according to claim 2, characterized in that, The base (8) is of a hollow structure.

4. The hot calibrating die for the inner ring of the cambered-blade titanium alloy stator static ring according to claim 2, characterized in that, The inner limiting pins (3) are provided with the lifting rings (4) between them.

5. The hot calibrating die for a cambered-blade titanium alloy stator inner ring according to claim 1, characterized in that, The adjusting pad (7) is of a ring structure with a thickness of 15-20 mm.

6. The hot calibrating die for a cambered-blade titanium alloy stator inner ring according to claim 1, characterized in that, The material of the inner taper ring (2) is selected from Cr18Ni12Mo2Ti.

7. The hot calibrating die for a cambered-blade titanium alloy stator inner ring according to claim 1, characterized in that, The radial thickness of the fan-shaped expansion petals (9) and the equal-width expansion petals (10) is: Where: R jh Theoretical height of the inside surface of the part to be corrected at the design drawing required correction point h Radius of the point; R xh Radius of the point at the theoretical height of the inner taper ring h Radius of the point; W bh Radial thickness of the point at the theoretical height of the sector and equal width bulge h Radial thickness of the point; α x Average linear expansion coefficient of the inner taper ring material at the hot correction temperature T Average linear expansion coefficient of the sector and equal width bulge material at the hot correction temperature α b Average linear expansion coefficient of the part to be corrected material at the hot correction temperature T Average linear expansion coefficient of the sector and equal width bulge material at the hot correction temperature α j Average linear expansion coefficient of the part to be corrected material at the hot correction temperature T Average linear expansion coefficient of the sector and equal width bulge material at the hot correction temperature Delta T Hot forming temperature T Temperature difference between the hot forming temperature and normal temperature.

8. The hot calibrating die for a cambered-blade titanium alloy stator inner ring according to claim 1, characterized in that, The half-cone angle of the inner conical ring (2) outer conical surface is Theta = 3°.

9. The method of claim 1-8, wherein the method is characterized in that, Firstly, the base (8) and the adjusting pad (7) are placed in the center of the workbench of the hydraulic machine, the part (5) to be corrected is placed on the adjusting pad (7) with the large end downward, and the part (5) to be corrected is concentric with the adjusting pad (7); then the fan-shaped expansion petals (9) are uniformly attached to the inner profile of the part (5) to be corrected in the circumferential direction; then the equal-width expansion petals (10) are sequentially arranged between the fan-shaped expansion petals and attached to the inner profile of the part (5) to be corrected; then the inner taper rings (2) are installed on the inner circumferences of the fan-shaped expansion petals (9) and the equal-width expansion petals (10), and the inner taper rings (2) are pressed to the bottom by uniformly pressing the upper end surfaces of the inner taper rings (2); then the outer heat insulation ring (1) is sleeved on the outer circumference of the part (5) to be corrected; the heat correction mold with the part (5) to be corrected is placed in the heat treatment furnace for heat correction, and the part (5) to be corrected is taken out after the surface temperature of the inner taper ring (2) is lower than 60 ℃, and the heat correction is completed. The part (5) to be corrected is taken out after the surface temperature of the inner taper ring (2) is lower than 60 ℃, and the heat correction is completed.

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