Forming die and forming method for eliminating ovality of profiled ring

Abstract

The application discloses a forming die for eliminating the ovality of a special-shaped ring piece, which is used for bulging and extruding forming of the special-shaped ring and comprises two symmetrically arranged bulging tools and a fastening tool. The two bulging tools are correspondingly spliced to form a die body, and the fastening tool is sleeved on the die body to fix the two bulging tools. The two bulging tools are spliced to form a special-shaped groove on the inner wall of the die body for bulging forming of the special-shaped ring and a mounting hole on the position of the central axis of the die body for fixing the die body on a bulging machine. Since the profile of the special-shaped groove is a design profile, the ring blank is locked by the forming die during bulging and extruding processing, the profile of the ring blank is guaranteed to be the profile of the special-shaped groove, and thus the ring blank is processed to have the design profile and size, so that the ovality of the part is eliminated, and the purpose of guaranteeing the dimensional stability of the special-shaped ring piece during the bulging and extruding process is achieved.

Description

Technical Field

[0001] This invention relates to the field of aero-engine parts technology, and in particular, to a forming mold for eliminating the ellipticity of irregularly shaped ring parts. Furthermore, this invention also relates to a forming method using the aforementioned forming mold. Background Technology

[0002] The front mounting edge is a component of an aero-engine or gas turbine. It is subjected to harsh conditions of high temperature for a long time. The material is mainly nickel-based high-temperature alloys such as GH3536. It is usually made from forged blanks. The existing front mounting edges of aero-engines are usually ring structures and are made by irregular ring rolling.

[0003] Reference Figure 5 The diagram shows the structure of the irregular ring 400, specifically, which includes an annular component. The annular component is rolled to form annular protrusions 401 at both ends. When two annular protrusions 401 are spaced apart, an annular groove 402 is formed in the middle of the annular component. Current manufacturing processes involve placing the ring blank into a mandrel and then rolling it. Unlike rectangular cross-section rings where the inner and outer contour radii are fixed values, the outer contour of the irregular ring is non-rectangular, and the radii of its inner and outer contours are not single values ​​but multiple values. Correspondingly, the working radius of the rolling mill for non-rectangular cross-section rings is also multi-valued. During rolling, the rolling mill, rotating in motion, has different linear velocities at different working radii. This results in different rolling speeds and different rolling frictions at the contact surface between the rolling mill and the ring during the rolling of non-rectangular cross-section rings. This can lead to a risk of the entire annular component of the manufactured irregular ring becoming elliptical. This reduces the probability of producing a qualified irregular ring to some extent. Summary of the Invention

[0004] This invention provides a forming mold and forming method for eliminating ellipticity in irregularly shaped ring parts, in order to solve the technical problem of how to eliminate ellipticity in the production process of irregularly shaped ring parts.

[0005] According to one aspect of the present invention, a forming mold for eliminating the ellipticity of irregularly shaped rings is provided for the bulging and forming of irregularly shaped rings. The forming mold includes two symmetrically arranged bulging and forming tools and a fastening tool. The two bulging and forming tools are spliced ​​together to form a mold body. The fastening tool is sleeved on the mold body to fix the two bulging and forming tools. The two bulging and forming tools are spliced ​​together to form an irregular groove on the inner wall of the mold body for the bulging and forming of irregularly shaped rings and a mounting hole on the central axis of the mold body for fixing the mold body to a forming machine.

[0006] Furthermore, the irregular groove includes a first annular groove, a second annular groove, and an annular rib located between the first annular groove and the second annular groove, which are spaced apart along the height direction of the mold body. The first annular groove, the second annular groove, and the annular rib are coaxially arranged. The first annular groove and the second annular groove have the same diameter and the same groove width. The inner diameter of the annular rib is smaller than the diameter of the first annular groove.

[0007] Furthermore, the mounting hole is coaxially arranged with and communicates with the first annular groove.

[0008] Furthermore, the bottom corners of the first and second annular grooves are set as arc angles, and the inner circle corner of the annular rib is set as an arc angle.

[0009] Furthermore, the outer circumference of the mold body is provided with an annular step, and the fastening fixture is fitted on the annular step and adapted to the annular step.

[0010] According to another aspect of the present invention, a forming method for eliminating the ellipticity of irregularly shaped ring parts is also provided, the forming method comprising the following steps:

[0011] S100: Cut the bar stock into blanks according to the set length dimensions;

[0012] S200: Cut both ends of the blank flat, and then round the corners at both ends of the blank;

[0013] S300: Heat the billet to the set temperature and then hold it at that temperature;

[0014] S400: Upset the billet heated in step S300, and then punch holes in the billet to form a ring billet;

[0015] S500: Heat the ring blank to the set temperature and then hold it at that temperature;

[0016] S600: Transfer the heated ring blank from step S500 to a ring rolling mill for ring rolling, so that a ring groove is formed in the middle of the ring blank;

[0017] S700: Transfer the ring blank after ring rolling to the bulging machine, so that the center hole of the ring blank is fitted into the working center of the bulging machine. Then, assemble the die body on the surface of the ring blank so that the ring blank fits into the shaped groove. Then, put the fastening fixture on the die body and start the bulging machine to expand the ring blank to fill the shaped groove.

[0018] Furthermore, in step S200, the radius of the rounded corner is 5mm to 8mm.

[0019] Furthermore, step S300 specifically includes the following steps:

[0020] S301: Place the billet into the heating furnace for preheating, and then hold it at the set temperature;

[0021] S302: Increase the temperature of the heating furnace to heat the preheated billet to a high temperature. After heating the billet to the set temperature, it is then kept warm.

[0022] Furthermore, in step S400, after punching the blank, the hole in the blank is enlarged using a frame so that the diameter of the central hole in the blank can be adapted to the core roller on the ring rolling mill.

[0023] Furthermore, step S600 specifically includes the following steps:

[0024] S601: Place the ring blank onto the core roller of the ring rolling mill, then move the core roller to embed the ring blank into the shaped groove of the main roller, and then make the upper conical roller and the lower conical roller abut against the upper end face and the lower end face of the ring blank, respectively.

[0025] S602: Start the ring rolling mill to form a ring groove in the middle of the ring blank.

[0026] The present invention has the following beneficial effects:

[0027] This invention provides a forming mold to eliminate the ellipticity of irregularly shaped rings, ensuring the dimensional stability of the rings during the bulging process. Specifically, the ring blank to be processed is first placed on the worktable of the bulging machine, ensuring that the ring blank is coaxial with the working center of the bulging machine. Then, two symmetrical special bulging fixtures are closed, so that the mold body surrounds the ring blank. At this time, the lower end face of the mold body abuts against the working surface of the bulging machine, and the working center of the bulging machine passes through the mounting hole, so that the mold body and the bulging machine are also coaxial. The ring blank is exactly matched with the irregular groove formed by the closed mold body. Then, the two bulging fixtures are clamped and fixed by fastening fixtures. After the ring blank and forming mold are assembled, the bulging machine is turned on, and the working center of the bulging machine applies pressure to the ring blank. The outward-diffused extrusion force expands the ring blank, causing the outer side of the ring blank to contact and fit against the groove wall. Since the contour of the groove is the design contour, the ring blank is locked by the forming mold during the extrusion process to ensure that the outer contour of the ring blank is the contour of the groove. Because the groove of the mold body is a standard design contour and size, after the ring blank is expanded, the outer contour of the ring blank is consistent with the contour of the groove, thus making the ring blank processed into the design contour and size. In this way, the ring blank will not have the risk of being elliptical, thereby eliminating the ellipticity of the part and ensuring the dimensional stability of the irregular ring part during the extrusion process.

[0028] Furthermore, the present invention also provides a method for forming irregularly shaped ring parts. First, a bar stock is cut to a predetermined length using a saw to form a cylindrical blank to be processed. Then, the blank is placed on a lathe to cut both ends, making the end faces flat. Next, a chamfering machine is used to round the ends of the blank, giving the blank a smooth processing surface for subsequent processing. The blank, after its external contour has been trimmed, is then placed in a heating furnace for heating. The blank is then held at a certain temperature to ensure uniform heat distribution within the metal. After holding at this temperature for a period of time, the heated blank is placed on a forging press for forging, until the blank is forged to the desired shape. The forged billet, with an appropriate height and dimensions, is placed into a punching machine to create a ring blank. It is then reheated in a furnace to the set temperature and held for a period before being transferred to a ring rolling mill for ring rolling. This creates a ring groove in the center of the billet. The rolled ring blank is then transferred to an bulging machine, with the center hole of the billet positioned at the working center of the bulging machine. A forming die is then assembled onto the surface of the billet, aligning it with the groove. The bulging machine is then activated, causing the billet to expand and fill the groove, thus aligning the outline of the billet with that of the groove. Since the groove's outline is the design outline, the bulged billet also reaches the design dimensions. Through this method, because the groove in the die body has a standard design outline and dimensions, the outer outline of the billet matches the groove's outline after bulging, ensuring the billet is processed to the design outline and dimensions. This eliminates the risk of the billet becoming elliptical, thus eliminating part ellipticity and ensuring the dimensional stability of the shaped ring during the bulging process.

[0029] In addition to the objectives, features, and advantages described above, the present invention has other objectives, features, and advantages. The invention will now be described in further detail with reference to the figures. Attached Figure Description

[0030] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0031] Figure 1 This is a schematic diagram of the assembly of the mold body and the fastening fixture in a preferred embodiment of the present invention;

[0032] Figure 2 This is a schematic diagram of the extrusion tooling according to a preferred embodiment of the present invention;

[0033] Figure 3 This is a schematic diagram of the fastening fixture according to a preferred embodiment of the present invention;

[0034] Figure 4 This is a schematic diagram of a ring billet undergoing ring rolling according to a preferred embodiment of the present invention;

[0035] Figure 5 This is a schematic diagram of the existing ring blank structure;

[0036] Figure 6 This is a flowchart of a preferred embodiment of the irregular ring forming method of the present invention.

[0037] Legend:

[0038] 100. Mold body; 101. Extrusion fixture; 102. Irregular groove; 103. First annular groove; 104. Second annular groove; 105. Ring rib; 106. Mounting hole; 107. Annular step; 200. Fastening fixture; 300. Ring rolling mill; 301. Main roller; 302. Core roller; 303. Upper conical roller; 304. Lower conical roller; 400. Irregular ring; 401. Annular protrusion; 402. Annular groove. Detailed Implementation

[0039] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, the present invention can be implemented in many different ways as defined and covered below.

[0040] like Figures 1-3 As shown, this is a forming mold for eliminating the ellipticity of an irregularly shaped ring according to an embodiment of the present invention, used for the bulging and extrusion forming of an irregularly shaped ring 400. The forming mold includes two symmetrically arranged bulging and extrusion fixtures 101 and a fastening fixture 200. The two bulging and extrusion fixtures 101 are spliced ​​together to form a mold body 100. The fastening fixture 200 is sleeved on the mold body 100 to fix the two bulging and extrusion fixtures 101. The two bulging and extrusion fixtures 101 are spliced ​​together to form an irregular groove 102 on the inner wall of the mold body 100 for the bulging and forming of the irregularly shaped ring, and a mounting hole 106 on the central axis of the mold body 100 for fixing the mold body 100 on the bulging machine.

[0041] Specifically, the forming mold includes three parts: two symmetrically arranged extrusion fixtures 101 and a fastening fixture 200. The two extrusion fixtures 101 are spliced ​​together to form the mold body 100. The mold body 100 is locked by the fastening fixture 200 to form the forming mold. The two extrusion fixtures 101 are spliced ​​together to form a shaped groove 102 for the shaped ring 400 to expand and form, and a mounting hole 106 for fixing the mold body 100 on the expansion forming machine. In this embodiment, the fastening fixture 200 is annular, and the mold body 100 has an annular step 107 adapted to the fastening fixture 200. Specifically, the fastening fixture 200 is set in annular shape, and the assembled mold body 100 is formed with an annular step 107, so that the fastening fixture 200 is fitted onto the annular step 107. Since both the mold body 100 and the fastening fixture 200 are annular, the forming mold can be subjected to uniform force when the bulging machine is working, preventing damage to the mold due to uneven force. At the same time, the groove wall of the irregular groove 102 matches the outer contour of the finished irregular ring 400, conforming to the standard design dimensions. Therefore, after the irregular ring 400 is constrained and processed on the bulging machine by the forming mold, the ovality of the part can be eliminated during processing, ensuring the dimensional stability of the irregular ring 400 during the bulging process.

[0042] In actual operation, the ring blank to be processed is first placed on the worktable of the bulging machine, ensuring that the ring blank is coaxial with the working center of the bulging machine. Then, two symmetrical special bulging fixtures 101 are closed, so that the mold body 100 wraps around the ring blank. At this time, the lower end face of the mold body 100 abuts against the working surface of the bulging machine, and the working center of the bulging machine passes through the mounting hole 106, so that the mold body 100 and the bulging machine are also coaxial. The ring blank is just embedded in the irregular groove 102 formed by the closed mold body 100. Then, the fastening fixture 200 holds and fixes the two bulging fixtures 101 tightly. After the ring blank and the forming mold are assembled, the bulging machine is turned on, and the working center of the bulging machine applies pressure to the ring blank. An outwardly expanding force is applied to locally expand the ring blank, causing the outer side of the ring blank to contact and fit against the groove wall of the irregular groove 102. Since the contour of the irregular groove 102 is the design contour, the ring blank is locked by the forming mold during the expansion process to ensure that the contour of the ring blank is the contour of the irregular groove 102. Because the irregular groove 102 of the mold body 100 is a standard design contour and size, after the ring blank is expanded, the outer contour of the ring blank is consistent with the contour of the irregular groove 102, so that the ring blank is processed into the design contour and size. In this way, the ring blank will not have the risk of being elliptical, thereby eliminating the ellipticity of the part and ensuring the dimensional stability of the irregular ring 400 during the expansion process.

[0043] Furthermore, the irregular groove 102 includes a first annular groove 103, a second annular groove 104 and an annular rib 105 located between the first annular groove 103 and the second annular groove 104, which are spaced apart along the height direction of the mold body 100. The first annular groove 103, the second annular groove 104 and the annular rib 105 are coaxially arranged. The first annular groove 103 and the second annular groove 104 have the same diameter and the same groove width. The inner diameter of the annular rib 105 is smaller than the diameter of the first annular groove 103. Specifically, the annular rib 105 is used to extend into the annular groove 402 in the middle of the irregular ring 400, and the annular protrusions 401 at both ends of the irregular ring 400 extend into the first annular groove 103 and the second annular groove 104 respectively. In specific implementation, the annular protrusions 401 at both ends of the ring blank are respectively matched with the first annular groove 103 and the second annular groove 104, and the annular groove in the middle of the ring blank is for the annular rib 105 to extend into. Then, the ring blank is expanded using a forming machine, so that the annular protrusions 401 at both ends of the ring blank are completely fitted with the groove walls of the first annular groove 103 and the second annular groove 104, and the groove wall of the annular groove 402 in the middle of the ring blank is completely fitted with the surface of the annular rib 105, so that the processed ring blank has the designed outline and dimensions.

[0044] In one embodiment, the mounting hole 106 is coaxially arranged with and communicates with the first annular groove 103. Specifically, the mounting hole 106 is used for the working center shaft of the bulging machine to pass through. The coaxial arrangement of the mounting hole 106 and the first annular groove 103 can save design space for the forming mold on the one hand, and on the other hand, it allows the working center shaft of the bulging machine to pass through the irregular groove 102 and the mounting hole 106 in sequence, thereby facilitating the embedding of the ring blank into the irregular groove 102 and benefiting the processing and forming of the irregular ring 400.

[0045] Furthermore, the corners at the bottom of the first annular groove 103 and the second annular groove 104 are set as arc corners, and the corners on one side of the inner circle of the annular rib 105 are set as arc corners.

[0046] Specifically, failing to use rounded transitions at corners in forging die design poses the following risks: 1. The ring blank may crack at the right angle during cooling; 2. The die may experience severe wear, reducing its lifespan. The rounded corners, however, ensure even stress distribution during ring blank fabrication, preventing damage due to uneven stress. Furthermore, after resetting the forming machine and removing the fastening fixture 200, the shaped ring 400 cools and shrinks, smoothly detaching from the forming die thanks to the rounded corners.

[0047] Furthermore, the mold body 100 is provided with an annular step 107, and the fastening fixture 200 is fitted onto the annular step 107 and is adapted to the annular step 107. Specifically, the fastening fixture 200 is annular, and the annular fastening fixture 200 can be evenly stressed when the inner circle is subjected to a uniformly outwardly diffused force, making it less prone to damage.

[0048] like Figure 6According to another aspect of the present invention, a forming method for eliminating the ellipticity of 400 irregularly shaped rings is also provided. The forming method includes the following steps:

[0049] S100: Cut the bar stock into blanks according to the set length dimensions;

[0050] Regarding step S100, in this embodiment, the material of the bar stock is GH3536. Because the irregular ring 400 is a non-standard part, its specific design dimensions are determined according to actual assembly requirements, so the length of the blank also needs to be set according to the actual situation. In specific implementation, the bar stock is placed on a saw, and the bar stock is cut into blanks according to the designed length dimensions by the saw.

[0051] S200: The two ends of the blank are cut flat, and then rounded corners are made at both ends of the blank;

[0052] In step S200, the two ends of the billet are machined using a lathe to create stable support surfaces, facilitating subsequent processing. Specifically, these stable support surfaces prevent the billet from being upset during the subsequent upsetting process. Upsetting misalignment hinders the production of standard ring billets, further impacting ring rolling and potentially resulting in irregular end faces of the shaped rings, affecting the final dimensions. Furthermore, while manual adjustment is possible after upsetting, it is time-consuming and labor-intensive. Excessive straightening time can lead to a drop in billet temperature and a risk of cracking. The machined billet is then rounded at both ends using a chamfering machine.

[0053] S300: Heat the billet to the set temperature and then hold it at that temperature;

[0054] In step S300, the billet is processed in a heating furnace to the set forging temperature, and then held at that temperature for a period of time, the specific time depending on the size of the billet. The purpose of holding the billet at that temperature is to ensure that the heat is evenly distributed inside the billet, guaranteeing that all parts of the billet reach the forging temperature. If this holding treatment is not performed, subsequent processes will result in uneven heating of the billet. Specifically, the surface temperature of the billet may reach the forgeable temperature, but the internal temperature of the billet may be lower than the surface temperature, or the internal temperature of the billet may not reach the forgeable temperature. If forging is performed under these conditions, the billet may fracture.

[0055] S400: Upset the billet heated in step S300, and then punch holes in the billet to form a ring billet;

[0056] For step S400, the heated billet is first placed on the forging press for upsetting. After the billet is upset to the preset height and diameter values, the billet is punched through a punching machine to form a ring billet. Finally, the circular hole in the middle of the ring billet is enlarged by a frame to make the hole diameter reach the level that the core roller 302 of the ring rolling mill can pass through during subsequent ring rolling.

[0057] S500: Heat the billet to the set temperature and then hold it at that temperature;

[0058] Specifically, the heating temperature set in this step is the same as the T in step S300, and the holding time is determined according to the wall thickness of the ring blank.

[0059] Minimum holding time: Ring billet wall thickness × γ

[0060] Maximum heat preservation time: wall thickness of ring billet × &

[0061] S600: The ring blank heated in step S500 is transferred to the ring rolling mill 300 for ring rolling, so that a ring groove is formed in the middle of the ring blank;

[0062] Reference Figure 4 This diagram illustrates the ring rolling process for a ring billet. In step S600, the central hole of the ring billet is first inserted into the mandrel 302 of the rolling mill. Then, the mandrel 302 is moved so that the sidewall of the ring billet approaches the main roll 301. Next, the upper tapered roll 303 and the lower tapered roll 304 abut against the upper and lower end faces of the ring billet, respectively, to prevent insufficient levelness during ring processing. It is important to ensure that the forging temperature of the ring billet after ring rolling is at least 70°C above the nominal final forging temperature, and it is transferred to the bulging machine for bulging within 15 seconds. If the temperature is below 70°C above the nominal final forging temperature, the ring billet will continuously cool down during bulging, potentially causing the temperature to drop below the final forging temperature at the start of bulging, leading to excessive hardness and brittle fracture, as well as mixed crystal formation after subsequent heat treatment. If the transfer time exceeds 15 seconds, the cooling time will be too long, and the temperature of the ring blank at the beginning of the expansion and extrusion will be lower than the nominal final forging temperature. This will also cause the ring to be too hard and brittle, as well as mixed crystals after subsequent heat treatment.

[0063] S700: Transfer the ring blank after ring rolling to the bulging machine, so that the center hole of the ring blank is fitted into the working center of the bulging machine. Then, assemble the forming mold on the surface of the ring blank so that the ring blank matches the shaped groove 102. Then start the bulging machine to expand the ring blank to fill the shaped groove 102.

[0064] In step S700, the ring blank after ring rolling is immediately transferred to the bulging machine to ensure that the temperature during bulging is above the nominal final forging temperature. Specifically, the center hole of the ring blank is fitted onto the shaft of the working center of the bulging machine, ensuring that the ring blank and the working center of the bulging machine are coaxial during placement to avoid localized bulging of the ring blank during operation, which could lead to uneven deformation. Then, two symmetrically arranged bulging fixtures 101 are quickly closed and locked using fastening fixtures 200. At this time, the ring blank is accommodated in the shaped groove 102. Finally, the bulging machine is started to bulge the ring blank, making the outer contour of the ring blank match the shaped groove 102, so that the bulged ring blank meets the design dimensions, thereby eliminating the ellipticity of the shaped ring 400. Since the contour of the shaped groove 102 is the design contour, the bulged ring blank also reaches the design dimensions. Through the above method, the ellipticity of the part is eliminated under the action of the forming die during ring blank processing, ensuring the dimensional stability of the shaped ring 400 during the bulging process.

[0065] In actual processing, when designing the irregular-shaped ring 400, such as... Figure 5 As shown, first determine the geometry of the cold-state blank (main dimensions are: outer diameter × inner diameter × height = D_cold × d_cold × H_cold). Since hot forgings shrink when cooled to room temperature, the linear expansion coefficient of the relevant alloy needs to be consulted. For example, for GH3536, when the forging temperature drops from 900℃ to room temperature (20℃), the linear expansion coefficient A = 16.1 × 10⁻⁶. -6 ℃ -1 The coefficients of linear expansion for different types of metallic materials at different temperatures can be found in the *China Aviation Materials Handbook*. Then, the ring rolling parameters are set on the 300 ring rolling mill, specifically the intermediate hot dimensions of the blank, with the main dimensions being: outer diameter × inner diameter × height = D_hot × d_hot × H_hot. Next, the bulging parameters are set on the bulging mill, only the inner diameter d of the ring blank needs to be set. The bulging time for the 400 shaped ring on the bulging mill must be less than 9 seconds, for the following reasons:

[0066] When the pressure holding time is controlled within 5 seconds, Φd 胀 =Φd 热 +(8~10)=Φd 冷 +Φd 冷 ×(final forging temperature - room temperature) × A, other dimensions are determined based on the conservation of billet volume. It should be noted that when the holding time is within 5 seconds, the final forging temperature of the shaped ring can be guaranteed to be above the final forging temperature specified in the process. At this time, it can be guaranteed that the dimensions of the shaped ring after thermal shrinkage are consistent with the specified dimensions of the cold blank.

[0067] When the holding time is controlled between 5 and 9 seconds, Φd_expansion = Φd_hot + (4 to 6) = Φd_cold + Φd_cold × (final forging temperature - room temperature) × A`. Other dimensions are determined based on the conservation of billet volume. It should be noted that when the holding time is between 5 and 9 seconds, the thermal shrinkage of the irregular ring will decrease accordingly after the bulging machine resets, therefore A` is less than A.

[0068] When the pressure holding time exceeds 9 seconds, the time is too long and will affect production efficiency.

[0069] After the bulging of the irregular part 400 is completed, first control the bulging machine to reset, then remove the fastening fixture 200, and finally separate the bulging fixture 101 to remove the processed irregular ring 400. In actual operation, the irregular ring forging will smoothly detach from the forming mold due to the cooling and shrinkage, with the help of the arc angle inside the bulging fixture 101.

[0070] Furthermore, in step S200, the radius of the fillet is 5mm. Specifically, the fillet is used to protect the billet during subsequent forging, preventing damage due to sharp edges on the end face. A radius of 5mm is a standard design size; in other embodiments, the radius can be set to 8mm depending on the size of the billet. If the radius is too small, the protective effect is limited, and the risk of cracking and damage to the billet during forging remains. If the radius is too large, it will waste material.

[0071] Furthermore, step S300 specifically includes the following steps:

[0072] S301: Place the billet into the heating furnace for preheating, and then hold it at the set temperature;

[0073] S302: Increase the temperature of the heating furnace to heat the preheated billet to a high temperature. After heating the billet to the set temperature, it is then kept warm.

[0074] Reference Figure 5 Specifically, the holding time is related to the diameter of the billet. The specific heating process is as follows:

[0075] 1. When the billet enters the heating furnace, the temperature of the heating furnace must be less than or equal to T_entry. A certain distance must be maintained between billets when they enter the furnace.

[0076] 2. Preheat the billet to a temperature of Tpre. Once the preheating temperature is reached, keep the billet warm.

[0077] Minimum heat preservation time: D×α

[0078] Maximum heat preservation time: D×β

[0079] 3. The billet is subjected to high-temperature treatment to bring it to the temperature required for forging. At this time, the temperature of the heating furnace is raised to T high.

[0080] Once the required forging temperature is reached, the billet is kept warm.

[0081] Among them, the shortest heat preservation time is: D×γ

[0082] Maximum heat retention time: D×&

[0083] Note: Tin: The upper limit of the furnace temperature when the billet enters the furnace. In order to ensure that the billet is preheated sufficiently and reduce thermal stress, the temperature of the billet when it enters the furnace needs to be lower than Tin.

[0084] Tpre: This value depends on the material type; different materials require different preheating temperatures.

[0085] Thigh: This value is the set temperature for high-temperature heating of the billet. When the material is GH3536, the range of Thigh is 1120℃-1180℃. If the temperature is below 1120℃, the billet cannot reach the temperature required for subsequent forging, which will lead to work hardening of the billet in the later stage, and in severe cases, it may cause the billet to break. If the temperature is above 1180℃, the billet will also be at risk of overheating and burning during heating and subsequent forging.

[0086] D: D represents the diameter of the billet. Specifically, the diameter D of the billet is smaller than the length of the billet, and the minimum value of the two is selected as the effective size during heating.

[0087] α and β are the lower and upper limits of the heating coefficient during preheating; γ and & are the lower and upper limits of the heating coefficient at high temperature.

[0088] Furthermore, in step S400, after punching the blank, the blank hole is enlarged using a frame so that the diameter of the blank center hole can be adapted to the core roller 302 on the ring rolling mill 300.

[0089] Specifically, after punching the blank, the hole diameter is generally difficult to meet the requirements of the core roller 302 on the ring rolling mill 300, and the hole needs to be widened. In actual operation, the process of widening the hole using a frame is usually adopted so that the diameter of the center hole of the blank can be matched with the core roller 302 on the ring rolling mill 300.

[0090] Furthermore, step S600 specifically includes the following steps:

[0091] S601: The ring blank is placed on the core roller 302 of the ring rolling mill 300, and then the core roller 302 is moved to embed the ring blank into the main roller 301, so that the ring blank contacts the rolling surface of the main roller 301, and then the upper tapered roller 303 and the lower tapered roller 304 abut against the upper end face and the lower end face of the ring blank, respectively.

[0092] For step S601, first insert the circular hole in the middle of the ring blank into the core roll 302 of the rolling mill, then move the core roll 302 to embed the ring blank into the main roll 301, so that the ring blank and the rolling surface of the main roll 301 come into contact, and then the upper tapered roll 303 and the lower tapered roll 304 abut against the upper end face and the lower end face of the ring blank respectively to prevent insufficient levelness during the processing of the ring blank.

[0093] It is important to note that the temperature of the ring billet after ring rolling must be maintained at 70°C above the nominal final forging temperature, and it must be transferred to the bulging machine for bulging within 15 seconds. If the temperature is below 70°C above the nominal final forging temperature, the ring billet will continuously cool down during the bulging process, potentially causing the temperature to drop below the final forging temperature at the beginning of bulging. This could lead to excessive hardness and brittleness, as well as mixed crystal formation after subsequent heat treatment. Conversely, if the transfer time exceeds 15 seconds, the prolonged cooling time will also cause the ring billet temperature to drop below the nominal final forging temperature at the start of bulging, again resulting in excessive hardness, brittleness, and mixed crystal formation after subsequent heat treatment.

[0094] S602: Start the ring rolling mill 300 to form a ring groove in the middle of the ring blank.

[0095] In step S602, the ring rolling mill 300 is turned on, and the main roller 301 extrudes the ring blank, so that a ring groove is formed in the middle of the ring blank. After the ring groove is formed, it is used to cooperate with the ring rib 105 in the forming mold, thereby performing stable expansion and extrusion of the ring blank.

[0096] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A forming die for eliminating the ellipticity of irregularly shaped rings, used for the extrusion molding of irregularly shaped rings, characterized in that, The forming mold includes two symmetrically arranged extrusion fixtures (101) and fastening fixtures (200). The two extrusion fixtures (101) are spliced ​​together to form the mold body (100). The fastening fixtures (200) are sleeved on the mold body (100) to fix the two extrusion fixtures (101). The two extrusion fixtures (101) are spliced ​​together to form a shaped groove (102) on the inner wall of the mold body (100) for expanding and forming a shaped ring, and an mounting hole (106) on the central axis of the mold body (100) for fixing the mold body (100) on the expansion machine. The irregular groove (102) includes a first annular groove (103), a second annular groove (104) spaced apart along the height direction of the mold body (100), and an annular rib (105) located between the first annular groove (103) and the second annular groove (104). The first annular groove (103), the second annular groove (104), and the annular rib (105) are coaxially arranged. The first annular groove (103) and the second annular groove (104) have the same diameter and the same groove width. The inner diameter of the annular rib (105) is... Smaller than the diameter of the first annular groove (103); specifically, the annular rib (105) is used to extend into the annular groove (402) in the middle of the irregular ring (400), and the annular protrusions (401) at both ends of the irregular ring (400) extend into the first annular groove (103) and the second annular groove (104) respectively; in specific implementation, the annular protrusions (401) at both ends of the ring blank are respectively matched with the first annular groove (103) and the second annular groove (104), and the annular groove in the middle of the ring blank is for the annular rib (105) to extend into; The bottom corners of the first annular groove (103) and the second annular groove (104) are set as arc corners, and the corners on one side of the inner circle of the annular rib (105) are set as arc corners. The outer circumference of the mold body (100) is provided with an annular step (107), and the fastening fixture (200) is sleeved on the annular step (107) and adapted to the annular step (107); During operation, the billet is first heated to the set temperature and then kept warm. Then, the heated ring billet is transferred to the ring rolling mill (300) for ring rolling, so that a ring groove is formed in the middle of the ring billet. Finally, the ring-rolled ring billet is transferred to the bulging machine, so that the center hole of the ring billet is fitted in the working center of the bulging machine. Then, the forming mold is assembled on the surface of the ring billet, so that the ring billet matches the shaped groove (102). Then, the bulging machine is started to expand the ring billet to fill the shaped groove (102). During operation, the ring-rolled ring billet is transferred to the bulging machine as soon as possible to ensure that the temperature during bulging is above the final forging temperature.

2. The forming mold for eliminating the ellipticity of irregularly shaped ring parts according to claim 1, characterized in that, The mounting hole (106) is coaxially arranged with the first annular groove (103) and communicates with the first annular groove (103).

3. A forming method for eliminating the ellipticity of irregularly shaped ring parts, characterized in that, Using a forming mold for eliminating the ellipticity of irregularly shaped ring parts as described in any one of claims 1-2, the forming method includes the following steps: S100: Cut the bar stock into blanks according to the set length dimensions; S200: Cut both ends of the blank flat, and then round the corners at both ends of the blank; specifically, the radius of the rounded corner is 5mm; S300: Heat the billet to the set temperature and then hold it at that temperature; S400: Upset the billet heated in step S300, and then punch holes in the billet to form a ring billet; S500: Heat the ring blank to the set temperature and then hold it at that temperature; S600: Transfer the heated ring blank from step S500 to the ring rolling mill (300) for ring rolling, so that a ring groove is formed in the middle of the ring blank; specifically including: S601: Place the ring blank on the mandrel (302) of the ring rolling mill (300), and then move the mandrel (302) to embed the ring blank into the main roll (301), so that the ring blank contacts the rolling surface of the main roll (301), and then make the upper conical roll (303) and the lower conical roll (304) abut against the upper end face and the lower end face of the ring blank respectively; S602: Turn on the ring rolling mill (300) to form a ring groove in the middle of the ring blank; Among these requirements, it is necessary to ensure that the temperature of the ring billet after ring rolling is 70°C above the final forging temperature, and to transfer it to the bulging machine for bulging within 15 seconds. S700: Transfer the ring blank after ring rolling to the bulging machine, so that the center hole of the ring blank is fitted in the working center of the bulging machine, then assemble the die body (100) on the surface of the ring blank, so that the ring blank fits with the shaped groove (102), then put the fastening fixture (200) on the die body (100), and then start the bulging machine to expand the ring blank to fill the shaped groove (102).

4. The forming method for eliminating the ellipticity of irregularly shaped rings according to claim 3, characterized in that, Step S300 specifically includes the following steps: S301: Place the billet into the heating furnace for preheating, and then hold it at the set temperature; S302: Increase the temperature of the heating furnace to heat the preheated billet to a high temperature. After heating the billet to the set temperature, it is then kept warm.

5. The forming method for eliminating the ellipticity of irregularly shaped rings according to claim 3, characterized in that, In step S400, after punching the blank, the blank hole is further enlarged by a frame so that the diameter of the blank center hole can be adapted to the core roller (302) on the ring rolling mill (300).

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