GH4141 high-temperature alloy special-shaped high-vortex casing ring forging and forming method thereof

Abstract

The invention belongs to the technical field of aviation annular forge piece forming, and discloses a GH4141 high-temperature alloy special-shaped high-vortex casing ring forge piece and a forming method thereof, and the forming method comprises the steps of blanking, upsetting punching, trestle chambering, rectangular pre-rolling, special-shaped pre-rolling and special-shaped finish rolling; the first forging temperature in upsetting punching is 1040-1110 DEG C, the second forging temperature in trestle chambering is 1000-1080 DEG C, the third forging temperature in rectangular pre-rolling is 1040-1060 DEG C, the fourth forging temperature in special-shaped pre-rolling is 1040-1060 DEG C, rolling is performed through at least one heating number, the fifth forging temperature in special-shaped final rolling is 1040-1060 DEG C, and a ring blank is rolled into a ring forging through at least one heating number; and the blank is locally wrapped before the special-shaped pre-rolling and the special-shaped finish rolling are heated. The problems that the GH4141 high-temperature alloy ring forge piece is prone to cracking and uneven in structure in the forging process are solved, the prepared ring forge piece meets the product requirement, the rejection rate is greatly reduced, and crystal grains of the forge piece are even.

Description

Technical Field

[0001] The present invention relates to the technical field of aviation ring forging forming, and particularly relates to a special-shaped high-pressure turbine casing ring forging of GH4141 superalloy and a forming method thereof. Background Art

[0002] Fracture-prone and difficult-to-deform superalloys usually have high creep resistance, oxidation resistance and fatigue resistance, and can maintain good mechanical properties and structural stability under extreme harsh environments such as high temperature, high pressure and high speed, meeting the strict requirements for materials when the high-pressure turbine casing ring forging of an aeroengine operates at high temperature. Therefore, fracture-prone and difficult-to-deform superalloys are generally used to prepare the turbine casing ring forging, such as GH4141 superalloy. For a large-sized special-shaped casing ring forging using it, the inner diameter of the ring forging is greater than 600 mm, and the wall thickness is more than 50 mm. Due to the high degree of alloying of GH4141 and poor plasticity, the heating process requirements are high. During the forging process, if the heating rate is too fast or the furnace outlet temperature is uneven, it will cause too large a temperature difference between the inside and outside of the billet, easily resulting in brittle cracking, and the cracks are difficult to remove. On the other hand, the deformation resistance is large, and it is difficult for the alloy to complete recrystallization, resulting in easy occurrence of coarse grains and mixed grains in the forging, uneven organization or performance degradation.

[0003] To solve the above problems in the forging process of the GH4141 superalloy ring forging, in the prior art, a relatively large machining allowance is usually designed for the forging, and production is carried out in cooperation with a rectangular scheme. By multi-pass forging and reasonably distributing the deformation amount of each pass, the cracking tendency is reduced. However, this increases the feeding weight of the forging, resulting in a low utilization rate of raw materials, an increase in material costs, and high process requirements and a long process. In addition, there are also some methods to timely cover the coating during the forging process to reduce the heat loss on the surface of the billet. For example, patent document CN111069498 A discloses a room-temperature composite soft sleeve method for hot die forging of superalloy forgings. The sleeve method includes the following steps: cleaning the surface of the billet; cutting a coating suitable for the shape and size of the billet; applying a high-temperature binder on one side of the coating; covering the surface of the billet with the side of the coating applied with the high-temperature binder, and winding with a fiberglass cloth to obtain a sleeved billet; the coating is a silica-aluminum fiber blanket or silica-aluminum felt. Using the coating can make the surface quality of the forging better and the dimensional accuracy higher, which is beneficial to saving raw material costs and machining costs. However, this method needs to wrap the entire forging, and the preparation process is complex.

[0004] Therefore, it is necessary to develop a forming method suitable for the special-shaped high-pressure turbine casing ring forging of GH4141 superalloy. Summary of the Invention

[0005] The object of the present invention is to overcome the problems of easy cracking and uneven structure during the forging process of GH4141 superalloy ring forgings in the prior art, and to provide a special-shaped high-pressure compressor casing ring forging of GH4141 superalloy and a forming method thereof.

[0006] In order to achieve the above-mentioned invention object, the present invention provides the following technical solutions:

[0007] A forming method of a special-shaped high-pressure compressor casing ring forging of GH4141 superalloy, the forming method successively includes the following steps: blanking, upsetting and punching, mandrel expanding, rectangular pre-rolling, special-shaped pre-rolling and special-shaped finish rolling;

[0008] In upsetting and punching, the blank after blanking the GH4141 superalloy bar stock is heated to a first forging temperature, and the first forging temperature is 1040°C to 1110°C;

[0009] In mandrel expanding, the blank after upsetting and punching is heated to a second forging temperature and then mandrel expanded to obtain a ring blank with a rectangular cross-section, and the second forging temperature is 1000°C to 1080°C;

[0010] In rectangular pre-rolling, the ring blank with a rectangular cross-section is heated to a third forging temperature and then rolled, and the third forging temperature is 1040°C to 1060°C;

[0011] In special-shaped pre-rolling, the ring blank after rectangular pre-rolling is heated to a fourth forging temperature and then rolled, the fourth forging temperature is 1040°C to 1060°C, and the special-shaped pre-rolling is carried out by at least one heating pass;

[0012] In special-shaped finish rolling, the ring blank after special-shaped pre-rolling is heated to a fifth forging temperature, the fifth forging temperature is 1040°C to 1060°C, and the ring blank is rolled into a ring forging by at least one heating pass; before heating in special-shaped pre-rolling and special-shaped finish rolling, local cladding is adopted for the blank, and the local cladding is to cover the first surface and the second surface of the ring blank by bonding ceramic fibers, the first surface includes an upper end face, an inner side surface connected to the upper end face and having a width of 40 - 80 mm, and an outer side surface connected to the upper end face and having a width of 40 - 80 mm, and the second surface includes a lower end face, an inner side surface connected to the lower end face and having a width of 40 - 80 mm, and an outer side surface connected to the lower end face and having a width of 40 - 80 mm.

[0013] In the technical solution of the present invention, the forging of the GH4141 superalloy ring forging includes blanking, upsetting and punching, expanding with a mandrel, rectangular pre-rolling, special-shaped pre-rolling and special-shaped final rolling. Through the cooperation of rectangular pre-rolling, special-shaped pre-rolling and special-shaped final rolling and the limitation of the forging temperature of each process, on the one hand, it is beneficial to the special-shaped rolling of the high-pressure turbine casing ring forging with a large wall thickness, and on the other hand, it reasonably controls the deformation of the ring blank in different forging processes. At the same time, before heating in special-shaped pre-rolling and special-shaped final rolling, the blank is locally sheathed, and the blank under local sheathing is heated and rolled. The inventor found in practice that the cracks generated in the forging of the existing GH4141 superalloy ring forging are at the upper or lower end face corners. Through local sheathing treatment, it can effectively prevent the GH4141 superalloy from cracking at the corners due to too rapid temperature drop during the forging process after heating, with better heat preservation effect, reducing surface heat loss, and at the same time reducing the deformation resistance of the alloy, which is beneficial to the recrystallization of the alloy. Through the above technical solution, the parameters in the forming process are reasonably controlled, such as the processing sequence, heating temperature, rolling times, local sheathing, etc., solving the problems of easy cracking and uneven structure in the forging process of the GH4141 superalloy ring forging. The ring forging prepared by the present invention meets the product requirements, the rejection rate is greatly reduced, and the grains of the forging are relatively uniform.

[0014] As a preferred embodiment of the present invention, the first forging temperature in upsetting and punching is 1060°C to 1080°C, and the second forging temperature in expanding with a mandrel is 1060°C to 1080°C.

[0015] As a preferred embodiment of the present invention, the deformation amount in upsetting and punching is controlled to be 45% to 65%.

[0016] As a preferred embodiment of the present invention, the deformation amount in expanding with a mandrel is controlled to be 20% to 30%.

[0017] As a preferred embodiment of the present invention, rectangular pre-rolling is carried out through at least one heat treatment, and the deformation amount of each heat treatment is 15% to 25%.

[0018] As a more preferred embodiment of the present invention, the deformation amount of each heat treatment in special-shaped pre-rolling is 15% to 25%.

[0019] As a preferred embodiment of the present invention, special-shaped pre-rolling is carried out through two heat treatments, and the deformation amount of each heat treatment in special-shaped pre-rolling is 15% to 25%.

[0020] As a preferred embodiment of the present invention, the deformation amount in special-shaped final rolling is 15% to 20%.

[0021] As a preferred embodiment of the present invention, special-shaped final rolling is carried out through one heat treatment, and the deformation amount of each heat treatment in special-shaped final rolling is 15% to 20%.

[0022] As a preferred embodiment of the present invention, the thickness of the ceramic fiber is 10 mm - 30 mm, such as at least one of 10 mm, 11 mm, 12 mm, 13 mm, 14 mm, 15 mm, 16 mm, 17 mm, 18 mm, 19 mm, 20 mm, 21 mm, 22 mm, 22 mm, 23 mm, 24 mm, 25 mm, 26 mm, 27 mm, 28 mm, 29 mm, 30 mm. More preferably, the thickness of the ceramic fiber is 15 mm - 20 mm.

[0023] As a preferred embodiment of the present invention, in upsetting and punching, the first forging temperature is 1060 °C - 1080 °C, and the controlled deformation amount in upsetting and punching is 45% - 65%;

[0024] In cage ironing, the second forging temperature is 1060 °C - 1080 °C, and the controlled deformation amount in cage ironing is 20% - 30%;

[0025] In rectangular pre-rolling, the deformation amount per heating is 15% - 25%;

[0026] Special-shaped pre-rolling is carried out through two heatings, and the deformation amount of special-shaped pre-rolling per heating is 15% - 25%;

[0027] Special-shaped finish rolling is carried out through one heating, and the deformation amount of special-shaped finish rolling per heating is 15% - 20%.

[0028] As a preferred embodiment of the present invention, during the rectangular pre-rolling process, the blank is subjected to local cladding treatment before heating, and the method of local cladding is the same as that in the special-shaped pre-rolling or special-shaped finish rolling process.

[0029] On the other hand, the present invention also provides a GH4141 superalloy special-shaped high-pressure turbine casing ring forging, which is manufactured by the above forming method.

[0030] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0031] 1. The present invention provides a forming method for a GH4141 superalloy ring forging, including blanking, upsetting and punching, cage ironing, rectangular pre-rolling, special-shaped pre-rolling and special-shaped finish rolling. Through the cooperation of rectangular pre-rolling, special-shaped pre-rolling and special-shaped finish rolling and the limitation of the forging temperature of each process, on the one hand, it is beneficial to the special-shaped rolling of the high-pressure turbine casing ring forging with a larger wall thickness, and on the other hand, it reasonably controls the deformation of the ring blank in different forging processes. At the same time, before heating in special-shaped pre-rolling and special-shaped finish rolling, the blank is subjected to local cladding, and the blank under local cladding is heated and rolled. Through local cladding treatment, it can effectively prevent the GH4141 superalloy from cracking at the corners due to too fast temperature drop during the forging process after heating, with better heat preservation effect, reducing surface heat loss, and at the same time reducing the deformation resistance of the alloy, which is beneficial to the recrystallization of the alloy.

[0032] 2. The forming method of the present invention combines the jacket treatment for improving cracking, the heating temperature, and the control of the rolling deformation amount, adopts a near-net-shape forming scheme, reduces the margin in the forming design of the large-sized and abnormally-shaped casing of GH4141 alloy, reduces the feeding weight, thereby reducing the machining allowance of the forging. Compared with the material utilization rate of about 40% in the existing rectangular scheme, the material utilization rate of the forming method of the present invention is about 55%, and the raw material utilization rate is increased by more than 15%, thereby reducing the production cost; on the premise of ensuring the mechanical properties of the forging, the tissue uniformity of the forging is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a cross-sectional view of the large-sized and abnormally-shaped high-pressure turbine casing ring forging of GH4141 superalloy in Example 2;

[0034] Figure 2 It is a cross-sectional view of the ring blank after the jacket hole expansion in Example 2;

[0035] Figure 3 It is a cross-sectional view of the ring blank after the rectangular pre-rolling in Example 2;

[0036] Figure 4 It is a schematic diagram of the partial jacket treatment before the first abnormal pre-rolling in Example 2;

[0037] Figure 5 It is a cross-sectional view of the ring blank after the first abnormal pre-rolling in Example 2;

[0038] Figure 6 It is a schematic diagram of the partial jacket treatment before the second abnormal pre-rolling in Example 2;

[0039] Figure 7 It is a cross-sectional view of the ring blank after the second abnormal pre-rolling in Example 2;

[0040] Figure 8 It is a schematic diagram of the partial jacket treatment before the abnormal finish rolling in Example 2;

[0041] Figure 9 It is a cross-sectional view of the ring blank after the abnormal finish rolling forming in Example 2;

[0042] Markings in the figure: 1 - ring forging, 11 - ring blank, 12 - upper end face, 13 - lower end face, 14 - inner side face, 15 - outer side face, 2 - high-temperature binder, 3 - ceramic fiber. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0043] In order to more clearly describe the invention purpose, technical solution and technical effect advantages in the specific embodiments of the present invention, the following will make a detailed description of the solutions in the specific embodiments in combination with the accompanying drawings of the present invention. The specific technical solutions involved in the following specific embodiments are only for clearly and completely describing the innovative technical solutions of the present invention. They are only a part of the specific implementation solutions that the present invention can adopt, not all embodiments, and should not be understood as a limitation on the innovative solutions of the present invention. Any solution adopting the same inventive concept of the present invention should be included in the protection scope of the present invention.

[0044] Secondly, the relevant descriptions of the accompanying drawings in the specific embodiments of the present invention are only for facilitating those skilled in the art to understand the present invention solution. The partial details shown in the drawings are for clearly presenting the technical solution. It should not be considered that all the technical features in the drawings must be included in the specific embodiments, and even less should the detailed features in the drawings be regarded as additional limitations on the innovative technical solutions of the present invention. The components in each embodiment described and shown in the drawings can be combined and arranged in different configurations, and these variations in combination and arrangement should all be regarded as a part of all the embodiments of the innovative solution of the present invention and included in the scope to be protected by the present invention.

[0045] It should be noted that, without special instructions, in the description of the specific embodiments of the present invention, the expression terms of orientation or position relationship such as "upper", "lower", "left", "right", "center", "inner", "outer", etc. are all based on the orientation or position relationship shown in the drawings, or the orientation or position relationship when the invention product / device / device is usually used. These terms of orientation or position relationship are only for facilitating the description of the present invention solution or simplifying the description in the specific embodiments to facilitate those skilled in the art to quickly understand the solution, rather than indicating or implying that a specific device / component / element must have a specific orientation or be constructed and operated in a specific position relationship. Therefore, it cannot be understood as a limitation on the present invention.

[0046] In addition, when terms such as "horizontal", "vertical", "hanging", etc. appear, it does not mean that the corresponding device / component / element is required to be absolutely horizontal, vertical or hanging, but it can be slightly inclined. For example, "horizontal" only means that its direction is more horizontal relative to "vertical", and does not mean that the structure must be completely horizontal, but it can be slightly inclined. Or, it can be simply understood that the corresponding device / component / element is arranged in a specific direction such as "horizontal", "vertical", "hanging", etc., and can have an error / deviation of ±10% relative to the corresponding direction setting, more preferably within ±8%, more preferably within ±6%, more preferably within ±5%, and more preferably within ±4%. As long as the corresponding device / component / element is within the error / deviation range, it can still perform its function in the solution of the present invention.

[0047] In addition, when expressions such as "first", "second", "third", etc. appear in the terms, they are only used to distinguish the description of the same or similar components, and should not be understood as emphasizing or implying the relative importance of specific components.

[0048] In addition, in the description of the embodiments of the present invention, "several", "multiple", "a number of" represent at least 2. It can be any situation such as 3, 4, 5, 6, 7, 8, 9, etc., and even can be a situation exceeding 9.

[0049] In addition, in the description of the technical solution of the present invention, unless otherwise clearly specified / defined / limited, when terms such as "arranged", "installed", "connected", "linked" appear, they should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection. It can be connection means commonly used in the art such as welding, riveting, bolting, threaded connection, etc. Such a connection can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and can be the communication inside two components.

[0050] Embodiment 1

[0051] This embodiment provides a forming method for a special-shaped high-vortex casing ring forging of GH4141 superalloy. The forming method sequentially includes the following steps: blanking, upsetting and punching, horse-frame expanding, rectangular pre-rolling, special-shaped pre-rolling, and special-shaped final rolling;

[0052] In upsetting and punching, the blank after blanking the GH4141 superalloy bar is heated to a first forging temperature, and the first forging temperature is 1040°C to 1110°C;

[0053] In horse-frame expanding, the blank after upsetting and punching is heated to a second forging temperature and then horse-frame expanding is carried out to obtain a rectangular cross-section ring blank, and the second forging temperature is 1000°C to 1080°C;

[0054] In the rectangular pre-rolling, after heating the ring blank with a rectangular cross-section to the third forging temperature, rolling is carried out. The third forging temperature is 1040°C to 1060°C;

[0055] In the special-shaped pre-rolling, after heating the ring blank after rectangular pre-rolling to the fourth forging temperature, rolling is carried out. The fourth forging temperature is 1040°C to 1060°C, and the special-shaped pre-rolling is carried out through at least one heating pass;

[0056] In the special-shaped final rolling, the ring blank after special-shaped pre-rolling is heated to the fifth forging temperature. The fifth forging temperature is 1040°C to 1060°C, and the ring blank is rolled into a ring forging through at least one heating pass;

[0057] Before heating in the special-shaped pre-rolling and special-shaped final rolling, local cladding is applied to the blank. The local cladding is to cover the first surface and the second surface of the ring blank with ceramic fibers by bonding. The first surface includes the upper end face, the inner side face connected to the upper end face with a width of 40 - 80 mm, and the outer side face connected to the upper end face with a width of 40 - 80 mm. The second surface includes the lower end face, the inner side face connected to the lower end face with a width of 40 - 80 mm, and the outer side face connected to the lower end face with a width of 40 - 80 mm. It should be noted that, for example Figure 1 For the special-shaped high-pressure turbine casing ring forging 1, in Figure 4 the ring blank 11, the first surface of the ring blank 11 is the part of the surface of the ring blank 11 located on the upper top surface of the ring blank 11, which includes the entire upper end face 12 of the ring blank 11, as well as the surface of the inner side face 14 of the ring blank 11 close to the upper end face 12 with a width of 40 - 80 mm and the surface of the outer side face 15 of the ring blank 11 close to the upper end face 12 with a width of 40 - 80 mm. The second surface of the ring blank 11 is the part of the surface of the ring blank 11 located on the lower top surface of the ring blank 11, which includes the entire lower end face 13 of the ring blank 11, as well as the surface of the inner side face 14 of the ring blank 11 close to the lower end face 13 with a width of 40 - 80 mm and the surface of the outer side face 15 of the ring blank 11 close to the lower end face 13 with a width of 40 - 80 mm.

[0058] Example 2

[0059] This example provides a forming method for a special-shaped high-pressure turbine casing ring forging of GH4141 superalloy. The forming method of Example 1 is adopted, where the special-shaped high-pressure turbine casing ring forging is as Figure 1 shown, with an inner diameter of 780 mm, an outer diameter of 1000 mm, and a height of 300 mm. The method includes the following steps:

[0060] (1) Cut the GH4141 superalloy bar stock according to the size design of the ring forging, and the size of the cut bar stock is 300 - 400 mm;

[0061] (2) Then heat the blank after blanking to the first forging temperature and perform upsetting and punching to form a hole in the middle of the bar. The first forging temperature is 1060°C to 1080°C; control the deformation amount in upsetting and punching to be 45% to 65%;

[0062] (3) Heat the blank after upsetting and punching to the second forging temperature and perform cage expanding to make the hole diameter appropriate and the raw material volume reasonably distributed to obtain a ring blank with a rectangular cross-section, as Figure 2 shown. The second forging temperature is 1060°C to 1080°C; control the deformation amount in cage expanding to be 20% to 30%;

[0063] (4) Adopt the ring rolling process to heat the ring blank with a rectangular cross-section to the third forging temperature and perform rolling, as Figure 3 shown. The third forging temperature is 1040°C to 1060°C; the rectangular pre-rolling is carried out by at least one heating pass, and the deformation amount per heating pass is 15% to 25%;

[0064] (5) In the special-shaped pre-rolling, heat the ring blank after rectangular pre-rolling to the fourth forging temperature and perform rolling. The fourth forging temperature is 1040°C to 1060°C, and it is carried out by at least one heating pass. The deformation amount of each heating pass in the special-shaped pre-rolling is 15% to 25%; in this embodiment, the special-shaped pre-rolling is carried out by two heating passes. Before each heating pass of the special-shaped pre-rolling, the blank is locally covered with a sleeve, as Figure 4 、 Figure 5 、 Figure 6 、 Figure 7 shown, where the ceramic fiber 3 is bonded and covered on the first surface and the second surface of the ring blank through the high-temperature binder 2. The thickness of the used ceramic fiber is 15 mm - 20 mm, and it is a ceramic fiber cloth;

[0065] (6) Heat the ring blank after special-shaped pre-rolling to the fifth forging temperature. The fifth forging temperature is 1040°C to 1060°C, and the ring blank is rolled into a ring forging by at least one heating pass. The deformation amount of each heating pass in the special-shaped pre-rolling is 15% to 20%. Before each heating pass of the special-shaped final rolling, the blank is locally covered with a sleeve, as Figure 8 、 Figure 9 shown, and the blank is formed in one pass in the special-shaped final rolling.

[0066] The ring rolling process is to place the ring blank between the main ring rolling roll and the core ring rolling roll of the ring rolling machine. During the rolling process, as the core ring rolling roll moves towards the main ring rolling roll, the blank deforms along with the die shape and gradually thins while the diameter increases, and finally a ring forging with the required size is obtained. In ring rolling production, attention should be paid to the rolling speed and feed amount at the beginning of the rolling stage to ensure stable rolling and then appropriately increase the deformation amount.

[0067] Example 3

[0068] This embodiment provides a forming method for an abnormal high-vortex casing ring forging of GH4141 superalloy. The forming method of Example 2 is adopted, except that the size of the abnormal high-vortex casing ring forging prepared is different from that of Example 2. The inner diameter of the ring forging in this embodiment is 900 mm, the outer diameter is 1150 mm, and the height is 400 mm. The obtained ring forging.

[0069] Example 4

[0070] This embodiment provides a forming method for an abnormal high-vortex casing ring forging of GH4141 superalloy. The forming method of Example 2 is adopted, except that during the rectangular pre-rolling process, the blank is subjected to local cladding treatment before heating, and the method of local cladding is the same as that in the abnormal pre-rolling or abnormal finish-rolling process. The obtained ring forging.

[0071] Comparative Example 1

[0072] This comparative example provides a forming method for an abnormal high-vortex casing ring forging of GH4141 superalloy. The size of the ring forging is the same as that of Example 2, except that no cladding treatment is performed during the abnormal pre-rolling and abnormal finish-rolling processes. The forming method includes the following steps:

[0073] (1) Cut the GH4141 superalloy bar according to the size design of the ring forging, and the size of the cut bar is 300 - 400 mm;

[0074] (2) Then heat the cut blank to the first forging temperature and perform upsetting and punching to form a hole in the middle of the bar. The first forging temperature is 1060°C - 1080°C; control the deformation amount during upsetting and punching to be 45% - 65%;

[0075] (3) Heat the upset and punched blank to the second forging temperature and perform cage expanding to make the hole diameter appropriate and the raw material volume reasonably distributed to obtain a ring blank with a rectangular cross-section. The second forging temperature is 1060°C - 1080°C; control the deformation amount during cage expanding to be 20% - 30%;

[0076] (4) Use the ring rolling process to heat the ring blank with a rectangular cross-section to the third forging temperature and perform rolling. The third forging temperature is 1040°C - 1060°C; the rectangular pre-rolling is carried out by at least one heat treatment, and the deformation amount per heat treatment is 15% - 25%;

[0077] (5) In the abnormal pre-rolling, heat the ring blank after rectangular pre-rolling to the fourth forging temperature and perform rolling. The fourth forging temperature is 1040°C - 1060°C, and it is carried out by two heat treatments. The deformation amount of each heat treatment of abnormal pre-rolling is 15% - 25%;

[0078] (6) Heat the pre-rolled ring blank with special shape to the fifth forging temperature, which is 1040°C to 1060°C, and roll it into the ring forging of this comparative example in one pass during the final rolling with special shape. The deformation amount of the pre-rolling with special shape is 15% to 20%.

[0079] Comparative Example 2

[0080] This comparative example provides a forming method for a ring forging of a special-shaped high-pressure turbine casing made of GH4141 superalloy. The dimensions of the ring forging are the same as those in Example 2, except that the method of the cladding treatment during the pre-rolling with special shape and the final rolling with special shape is different from that in Example 2. In the cladding treatment, ceramic fibers are covered on the upper and lower end faces of the ring blank by bonding with a high-temperature binder. The forming method includes the following steps:

[0081] (1) Cut the GH4141 superalloy bar stock according to the dimension design of the ring forging, and the size of the cut bar is 300 - 400 mm;

[0082] (2) Then heat the blank after cutting to the first forging temperature and perform upsetting and punching to form a hole in the middle of the bar. The first forging temperature is 1060°C to 1080°C; control the deformation amount during upsetting and punching to be 45% - 65%;

[0083] (3) Heat the blank after upsetting and punching to the second forging temperature and perform cage expanding to make the hole diameter appropriate and reasonably distribute the raw material volume to obtain a ring blank with a rectangular cross-section. The second forging temperature is 1060°C to 1080°C; control the deformation amount during cage expanding to be 20% - 30%;

[0084] (4) Use the ring rolling process to heat the ring blank with a rectangular cross-section to the third forging temperature and then roll it. The third forging temperature is 1040°C to 1060°C; the rectangular pre-rolling is carried out through at least one heating pass, and the amount of each heating pass is 15% - 25%;

[0085] (5) In the pre-rolling with special shape, heat the ring blank after rectangular pre-rolling to the fourth forging temperature and then roll it. The fourth forging temperature is 1040°C to 1060°C, and it is rolled through two heating passes. The deformation amount of each heating pass of the pre-rolling with special shape is 15% - 25%. Before each heating pass of the pre-rolling with special shape, local cladding is carried out on the blank. In the cladding treatment, ceramic fibers are covered on the upper and lower end faces of the ring blank by bonding with a high-temperature binder;

[0086] (6) Heat the pre-rolled ring blank with special shape to the fifth forging temperature, which is 1040°C to 1060°C, and roll it into the ring forging of this comparative example in one pass during the final rolling with special shape. The deformation amount of the pre-rolling with special shape is 15% - 20%. Before the heating of the final rolling with special shape, local cladding is carried out on the blank. In the cladding treatment, ceramic fibers are covered on the upper and lower end faces of the ring blank by bonding with a high-temperature binder.

[0087] The ring forgings prepared in the above Examples 2, 3, 4, Comparative Example 1, and Comparative Example 2 were subjected to appearance inspection, and the number and length of cracks were recorded. At the same time, the mechanical properties of the ring forgings were tested, and the test results are shown in Table 1.

[0088] Table 1 Test Results of Ring Forgings Prepared in Examples 2-4 and Comparative Examples 1-2

[0089]

[0090] From the above results, it can be seen that the ring forgings prepared by the method of the present invention can all meet the requirements of having good mechanical properties. The ring forgings have no cracks or the crack depth is small, and can be processed during the subsequent machining process, and the products are qualified. Although the forgings in Comparative Example 1 and Comparative Example 2 also meet the mechanical property standards of the forgings, the elongation after fracture and reduction of area of the forgings in Comparative Example 1 are closer to the lower limit value of the standard requirements, and the plastic extension strength and hardness of the forgings in Comparative Example 2 are closer to the lower limit value of the standard requirements. The crack position appears at the corners of the upper end face or lower section of the ring forging, and the crack is deeper, greater than 5 mm, and cannot be processed during the subsequent machining process, resulting in unqualified products. In addition, the grain size of the ring forging in Example 2 was tested by an optical microscope. Under a high-power microscope, the grains of the ring forging are relatively uniform, above grade 4, which is beneficial to the subsequent machining of the ring forging and is not likely to cause part deformation.

[0091] The present invention can effectively prevent the situation of cracking defects at the corners due to excessive temperature drop during the forging process after heating of the large-sized casing of GH4141 alloy, thereby reducing the allowance in the forming design of the large-sized special-shaped casing of GH4141 alloy and reducing the consumption of raw materials. Combining the sheath treatment, heating temperature, and deformation amount control to improve the cracking situation, adopting a near-net-shape forming scheme, reducing the feeding weight, and increasing the raw material utilization rate by more than 15% (the utilization rate of the rectangular scheme is about 40%, and the utilization rate of the near-net-shape forming of this scheme is about 55%), thereby reducing the production cost.

[0092] For those skilled in the art, when understanding the solutions described in the specific embodiments of the present invention, they can refer to the conventional technical manuals in the art. At the same time, for the places where the above terms appear, they can make appropriate understandings or adjustments referentially. Without creative labor, the same or similar technical solution implementation situations can be deduced.

[0093] The above embodiments only describe the basic principles, main features, and / or advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and the description in the invention content part of the specification are only the principles or specific cases of the present invention. Without departing from the essence of the innovative idea of the present invention, there are various changes and improvements to the innovative solutions of the present invention, and these changes and improvements all fall within the scope of protection required by the present invention.

Claims

1. A forming method for a GH4141 high-temperature alloy special-shaped high-vortex casing ring forging, characterized in that: The forming method comprises the following steps in sequence: blanking, upsetting and punching, rack hole expansion, rectangular pre-rolling, special-shaped pre-rolling and special-shaped final rolling; During the upsetting and punching, the blank of the GH4141 high temperature alloy bar is heated to a first forging temperature, and the first forging temperature is 1040° C. to 1110° C.; In the rack expansion, the blank after upsetting and punching is heated to the second forging temperature and then expanded by the rack to obtain a rectangular cross-section ring blank, and the second forging temperature is 1000°C to 1080°C; In rectangular pre-rolling, the rectangular cross-section ring blank is heated to a third forging temperature and then rolled, and the third forging temperature is 1040° C. to 1060° C.; In the profile pre-rolling, the rectangular pre-rolled ring blank is heated to the fourth forging temperature and then rolled. The fourth forging temperature is 1040° C. to 1060° C. The profile pre-rolling is performed through at least one heat. The special-shaped final rolling heats the ring material after special-shaped pre-rolling to the fifth forging temperature, the fifth forging temperature is 1040℃~1060℃, and the ring blank is rolled into a ring forging through at least one fire; before the special-shaped pre-rolling and special-shaped final rolling heating, the blank is partially sheathed, and the partial sheathing is to cover the ceramic fiber to the first surface and the second surface of the ring blank by bonding, the first surface includes an upper end face, an inner side surface connected to the upper end face and with a width of 40~80mm, and an outer side surface connected to the upper end face and with a width of 40~80mm, and the second surface includes a lower end face, an inner side surface connected to the lower end face and with a width of 40~80mm, and an outer side surface connected to the lower end face and with a width of 40~80mm.

2. The forming method of the GH4141 high temperature alloy special-shaped high vortex casing ring forging according to claim 1 is characterized in that: The first forging temperature in upsetting and punching is 1060℃~1080℃, and the second forging temperature in rack expansion is 1060℃~1080℃.

3. The forming method of the GH4141 high temperature alloy special-shaped high vortex casing ring forging according to claim 1 is characterized in that: The deformation amount in upsetting and punching is controlled at 45% to 65%; the deformation amount in rack expansion is controlled at 20% to 30%.

4. The forming method of the GH4141 high temperature alloy special-shaped high vortex casing ring forging according to claim 1 is characterized in that: The rectangular pre-rolling is performed through at least one rolling process, and the deformation amount of each rolling process in the rectangular pre-rolling is 15% to 25%.

5. The forming method of the GH4141 high temperature alloy special-shaped high vortex casing ring forging according to claim 1 is characterized in that: The deformation of the special-shaped pre-rolling in each fire is 15% to 25%.

6. The forming method of the GH4141 high temperature alloy special-shaped high vortex casing ring forging according to claim 1 is characterized in that: The deformation of the final rolling is 15% to 20%.

7. The forming method of the GH4141 high temperature alloy special-shaped high vortex casing ring forging according to claim 1 is characterized in that: The thickness of ceramic fiber is 10mm-30mm.

8. The forming method of the GH4141 high temperature alloy special-shaped high vortex casing ring forging according to any one of claims 1 to 7, characterized in that: In the rectangular pre-rolling process, the billet is partially sheathed before heating. The method of partial sheathing is the same as that in the special-shaped pre-rolling or special-shaped final rolling process.

9. The forming method of the GH4141 high temperature alloy special-shaped high vortex casing ring forging according to any one of claims 1 to 7, characterized in that: The first forging temperature in the upsetting punching is 1060°C to 1080°C, and the deformation amount in the upsetting punching is controlled to be 45% to 65%; The second forging temperature in the horse frame hole expansion is 1060℃~1080℃, and the deformation amount in the horse frame hole expansion is controlled to be 20%~30%; The deformation of each fire in rectangular pre-rolling is 15% to 25%; The special-shaped pre-rolling is carried out through two fires, and the deformation of the special-shaped pre-rolling in each fire is 15% to 25%; The final rolling of the special-shaped product is carried out through one round of rolling, and the deformation of the special-shaped product in each round of rolling is 15% to 20%.

10. A GH4141 high temperature alloy special-shaped high-vortex casing ring forging, characterized in that: The ring forging is manufactured by the forming method of the GH4141 high-temperature alloy special-shaped high-vortex casing ring forging described in any one of claims 1 to 9.

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