Manufacturing method of GH4169 alloy turbine rear shaft forge piece and turbine rear shaft forge piece

Abstract

The invention discloses a manufacturing method of a GH4169 alloy turbine rear shaft forge piece and the turbine rear shaft forge piece. The method comprises the steps that the surface of a bar is polished; machining an annular material distribution belt on the side face of the bar in the circumferential direction to obtain a blank; performing primary soft sheathing on a second processing part of the blank, heating the blank, performing secondary soft sheathing on the heated blank, and performing heat preservation on the blank for a first preset duration; the first machining part of the blank subjected to heat preservation is drawn out; carrying out primary soft sheathing on the first processing part of the drawn blank, heating the blank, carrying out secondary soft sheathing on the heated blank, and carrying out heat preservation on the blank for a second preset duration; and the blank is subjected to die forging through the combined die, and the turbine rear shaft forged piece is obtained. According to the method, the first machining part of the blank is drawn out, the structure uniformity is improved, the structure grain size grade difference is reduced, the appearance of the forge piece is effectively adjusted by optimizing the design of the combined die, and therefore the usage amount of raw materials is reduced, and the production cost is reduced.

Description

Technical Field

[0001] The present application relates to the technical field of manufacturing GH4169 alloy turbine rear axle forgings, and in particular to a GH4169 alloy turbine rear axle forging manufacturing method and a turbine rear axle forging. Background Art

[0002] In the modern aerospace industry, turbine rear shaft forgings are key load-bearing parts, and their performance directly affects the overall operating efficiency and safety of the engine. GH4169 alloy is a nickel-based high-temperature alloy strengthened by body-centered tetragonal γ″ and face-centered cubic γ′ phase precipitation. Due to its excellent high-temperature performance and oxidation resistance, it is widely used in key load-bearing components of aircraft engines. The forgings used in the manufacture of these key load-bearing parts have very high performance requirements. For large-size variable-section power turbine rear shaft forgings, the traditional forming method usually adopts the process of "reduced upsetting ratio upsetting + constrained upsetting + rod extension + machining roughening + die upsetting".

[0003] However, the existing turbine rear shaft forgings usually require a large input of raw materials in the manufacturing process, the forging material consumption is large, the process is complex and the longitudinal section thickness of the forging varies greatly, the thicker section of the forging is very difficult to form, and the small head of the forging does not deform, which affects the uniformity of the forging structure. In the forging and processing process, the material characteristics are not fully utilized, resulting in increased material waste. Due to the unevenness of heat treatment and forging processes, the internal structure is unevenly distributed. This unevenness not only affects the mechanical properties of the forging, but may also lead to problems such as fatigue failure in actual applications, thereby reducing the service life and safety of the product. Summary of the invention

[0004] The main purpose of the present application is to provide a GH4169 alloy turbine rear shaft forging manufacturing method and turbine rear shaft forging, aiming to solve the technical problems of poor uniformity of the structure of the turbine rear shaft forging and large consumables.

[0005] To achieve the above-mentioned purpose, the present application provides a method for manufacturing a GH4169 alloy turbine rear shaft forging, the method comprising: grinding the surface of a bar; processing an annular dividing belt along the circumferential direction on the side of the bar to obtain a blank, wherein the dividing belt divides the blank into a first processing part and a second processing part relative to each other; soft-wrapping the second processing part of the blank once and heating the blank, soft-wrapping the heated blank a second time and keeping the blank warm for a first preset time; stretching the first processing part of the blank after being kept warm; and The first processing part of the blank is soft-wrapped once and the blank is heated, the heated blank is soft-wrapped twice and the blank is kept warm for a second preset time; the blank is die-forged using a combination mold, wherein the lower mold of the combination mold has a first mold cavity and a second mold cavity, and the upper mold of the combination mold has a raised portion adapted to the second mold cavity. When the blank is die-forged, the first processing part is placed in the first mold cavity, the upper mold applies pressure to the second processing part, and the raised portion extrude the second processing part to obtain a turbine rear shaft forging.

[0006] Optionally, the method further comprises:

[0007] Pre-treating the bar material to eliminate surface depressions of the bar material, and the ratio of the equivalent diameter to the depth of the surface depressions of the bar material is greater than or equal to a preset value;

[0008] Accordingly, the grinding of the bar surface includes:

[0009] The pre-treated bar is ground.

[0010] Optionally, the primary soft sheath is sheathed with two layers of aluminum silicate fiber felt and a thermocouple, and the secondary soft sheath is sheathed with aluminum silicate fiber felt and a high-temperature alloy binder.

[0011] Optionally, the step of soft-wrapping the second processed portion of the blank and heating the blank comprises:

[0012] Performing a soft coating on the second processed portion of the blank;

[0013] The blank after the soft packaging is heated to a first threshold temperature, and the blank is kept warm for a first threshold time;

[0014] Heating the blank after the first threshold time period of heat preservation to a second threshold temperature, and then heat preserving the blank for the second threshold time period;

[0015] Heating the blank that has completed the second threshold time period of heat preservation to a third threshold temperature, and heat preserving the blank for the third threshold time period;

[0016] Among them, the first threshold duration>the second threshold duration>the third threshold duration.

[0017] Optionally, the step of stretching the first processed portion of the blank after heat preservation comprises:

[0018] Preheat the die of the fast forging machine;

[0019] The fast forging machine is used to stretch the first processed portion of the blank after the insulation.

[0020] Optionally, the step of soft-wrapping the first processed portion of the drawn blank and heating the blank comprises:

[0021] Performing a soft coating on the first processed portion of the blank;

[0022] The blank after the soft packaging is heated to a first threshold temperature, and the blank is kept warm for a first threshold time;

[0023] Heating the blank after the first threshold time period of heat preservation to a second threshold temperature, and heat preserving the blank for the second threshold time period;

[0024] The blank that has completed the second threshold time period of heat preservation is heated to a third threshold temperature, and the blank is kept warm for the third threshold time period.

[0025] Optionally, the step of forging the blank using a combined die comprises:

[0026] When the zero point distance is within a first threshold range, controlling the pressing speed of the upper die to be the first threshold speed;

[0027] When the zero point distance is within the second threshold range, controlling the pressing speed of the upper die to be the second threshold speed;

[0028] When the zero point distance is within a third threshold range, controlling the pressing speed of the upper die to be a third threshold speed;

[0029] The zero point distance is the distance between the end surface of the upper die close to the lower die and the end surface of the lower die close to the upper die.

[0030] Optionally, after the raised portion extrude the second processed portion to obtain the turbine rear shaft forging, the method further includes:

[0031] A test ring is machined on the end surface of the turbine rear shaft forging corresponding to the second die cavity and facing away from the upper die;

[0032] performing a solid solution treatment on the turbine rear shaft forging;

[0033] The test rings were subjected to solution treatment and aging treatment.

[0034] To achieve the above-mentioned purpose, an embodiment of the present application further provides a turbine rear shaft forging, which is prepared based on any of the above-mentioned GH4169 alloy turbine rear shaft forging manufacturing methods, and the turbine rear shaft forging includes: a main body, a shaft, a recessed portion and a test ring; wherein the main body includes a first end face and a second end face that are relatively arranged; the second end face portion of the main body extends along the axial direction of the main body in a direction away from the first end face to form the shaft portion; the first end face portion of the main body is recessed along the axial direction of the main body in a direction close to the second end face to form the recessed portion; and the test ring is formed on the second end face of the main body.

[0035] Optionally, the shaft portion is a cylindrical structure, and the axes of the shaft portion, the body portion, the recessed portion and the test ring coincide with each other;

[0036] A rounded corner is provided at the position where the main body portion is connected to the shaft portion;

[0037] The cross section of the recessed portion along a direction parallel to the first end surface is circular, and the cross section along a direction perpendicular to the first end surface is an inverted trapezoid.

[0038] The present application proposes a method for manufacturing a GH4169 alloy turbine rear axle forging and a turbine rear axle forging. First, the surface of a bar is polished; an annular dividing belt is circumferentially processed on the side of the bar to obtain a blank, wherein the dividing belt divides the blank into a first processing portion and a second processing portion relative to each other; secondly, the second processing portion of the blank is soft-wrapped once and the blank is heated, the heated blank is soft-wrapped twice and the blank is kept warm for a first preset time; the first processing portion of the blank after being kept warm is stretched; stretching deformation is added to the first processing portion of the blank so that the microstructure is excellent. The present undeformed structure is formed, and the grain size difference with the second processing part is reduced; finally, the first processing part of the drawn billet is soft-wrapped once and the billet is heated, and the heated billet is soft-wrapped twice and the billet is kept warm for a second preset time; the billet is die-forged using a combination die, wherein the lower die of the combination die has a first die cavity and a second die cavity, and the upper die of the combination die has a convex portion adapted to the second die cavity. When the billet is die-forged, the first processing part is placed in the first die cavity, the upper die applies pressure to the second processing part, and the convex portion squeezes the second processing part to obtain the turbine rear shaft forging. By optimizing the design of the combination die, the shape of the turbine rear shaft forging is effectively adjusted, thereby reducing the use of raw materials and reducing production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 A schematic diagram of a process for manufacturing a GH4169 alloy turbine rear shaft forging provided in an embodiment of the present application;

[0040] Figure 2 This is a schematic diagram of a process of performing a soft coating on the second processing portion of the blank and heating the blank in an embodiment of the present application;

[0041] Figure 3 This is a schematic diagram of a process of performing a soft coating on the first processing portion of the drawn blank and heating the blank in an embodiment of the present application;

[0042] Figure 4 This is a schematic diagram of the process of die forging a blank using a combined die in an embodiment of the present application;

[0043] Figure 5 This is a simulation schematic diagram of stretching the first processed portion of the blank after heat preservation according to an embodiment of the present application;

[0044] Figure 6 This is a simulation schematic diagram of die forging a blank using a combined die in an embodiment of the present application;

[0045] Figure 7 A schematic diagram of the structure of a turbine rear shaft forging provided in an embodiment of the present application;

[0046] Figure 8 This is a schematic diagram of the structure of the second test ring S2 in this application;

[0047] Fig. 9 This is a schematic diagram of the temperature field simulation of the blank during die forging;

[0048] Fig.10 It is a schematic diagram of the limit pressing load of the hydraulic press forging the blank;

[0049] Fig.11 This is the high-magnification structure and grain size display of the first test ring S1;

[0050] Fig.12 This is the high-magnification structure and grain size display of the second test ring S2.

[0051] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0052] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0053] It should be noted that all directional indications in the embodiments of the present application (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0054] In this application, unless otherwise clearly specified and limited, the terms "connection", "fixation", etc. should be understood in a broad sense. For example, "fixation" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0055] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present application, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the meaning of "and / or" appearing in the full text includes three parallel schemes. Taking "A and / or B" as an example, it includes scheme A, or scheme B, or a scheme that satisfies both A and B. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in the field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by this application.

[0056] The present application is described in detail below with reference to the accompanying drawings and embodiments.

[0057] Figure 1 This is a schematic diagram of the process of manufacturing the GH4169 alloy turbine rear shaft forging provided in an embodiment of the present application. Figure 2 This is a schematic diagram of the process of performing a soft coating on the second processing part of the blank and heating the blank in the embodiment of the present application. Figure 3 This is a schematic diagram of a process of performing a soft coating on the first processing portion of the drawn blank and heating the blank in an embodiment of the present application. Figure 4 This is a schematic diagram of the process of die forging a blank using a combined die in an embodiment of the present application. Figure 5 This is a schematic diagram of a simulation of stretching the first processed portion of the blank after heat preservation in the embodiment of the present application. Figure 6 This is a simulation schematic diagram of die forging a blank using a combined die in an embodiment of the present application. Figure 7 This is a schematic diagram of the structure of the turbine rear shaft forging provided in an embodiment of the present application. Figure 8 This is a schematic diagram of the structure of the second test ring S2 in this application. Fig. 9 This is a schematic diagram of the temperature field simulation of the blank during die forging. Fig.10 This is a schematic diagram of the limit pressing load of the hydraulic press forging the blank. Fig.11 This is the high-magnification structure and grain size display of the first test ring S1. Fig.12 This is the high-magnification structure and grain size display of the second test ring S2.

[0058] The present application embodiment provides a method for manufacturing a GH4169 alloy turbine rear shaft forging, such as Figure 1-Figure 6 As shown, the method comprises the following specific steps:

[0059] S110, grinding the surface of the bar.

[0060] In an exemplary embodiment, the method described in the above step S110 may also include: pre-treating the rod material to eliminate surface depressions of the rod material, and the ratio of the equivalent diameter to the depth of the surface depressions of the rod material is greater than or equal to a preset value; accordingly, grinding the surface of the rod material may include: grinding the pre-treated rod material.

[0061] For example, the material of the bar stock may be GH4169 alloy, and the preset value may be 10. For example, if there is a circular depression with a diameter of X and a depth of Y on the surface of the GH4169 alloy bar stock, the depression of the bar stock needs to be polished so that the ratio of X to Y is greater than or equal to 10, which can effectively prevent folding or pinching at the depression during forging.

[0062] Furthermore, an annular dividing belt is processed circumferentially on the side of the bar to obtain a blank, wherein the dividing belt divides the blank into a first processing portion and a second processing portion that are opposite to each other, so as to perform subsequent forging on the blank.

[0063] S120, performing a soft wrapping on the second processing portion of the blank and heating the blank, performing a soft wrapping on the heated blank for a second time and keeping the blank warm for a first preset time.

[0064] In an exemplary embodiment, the primary soft covering may be a covering using two layers of aluminum silicate fiber felt and a thermocouple, and the secondary soft covering may be a covering using aluminum silicate fiber felt and a high-temperature alloy binder. Specifically, the secondary soft covering may be a secondary soft covering treatment for the first processing part and the second processing part at the same time to achieve heat preservation of the entire blank.

[0065] Exemplarily, the equivalent diameter of the blank can be 400 mm, the length of the blank can be 770 mm, the length of the first processing part can be 275 mm, and the length of the second processing part can be 495 mm; it should be noted that the length of the blank can also be 825 mm, the length of the first processing part can be 330 mm, and the length of the second processing part can be 495 mm; the above-mentioned dimensions of the blank are not limited in this embodiment.

[0066] As another example, the heating device for heating the blank may be a high-temperature electric furnace, the temperature uniformity of the high-temperature electric furnace may be ±10°C, and the first preset time may be 30 minutes, wherein it should be noted that the preset time is at least 30 minutes, and may also be more than 30 minutes. After the blank is soft-wrapped for the second time, the blank after the second soft-wrapping is placed in a high-temperature electric furnace for 30 minutes to keep warm, so that when the second processing part of the blank is stretched, the blank has a forging temperature, which is convenient for stretching the blank.

[0067] Specifically, the second processing part of the billet with a length of 770mm is soft-wrapped with two layers of aluminum silicate fiber felt and a thermocouple. After the second processing part is tightly wrapped, the billet is heated by a high-temperature electric furnace. After heating to the final insulation time, the billet is removed from the high-temperature electric furnace, and the billet is soft-wrapped with aluminum silicate fiber felt and high-temperature alloy binder for a second time, and the billet is placed in the high-temperature electric furnace for insulation for 30 minutes. Among them, the billet must be placed in the temperature control qualified area of ​​the high-temperature electric furnace, and the furnace of the high-temperature electric furnace should be swept forward before heating the billet. The billet is placed in the high-temperature electric furnace according to the ingot section number, and the placement position of each billet is recorded. The billet must be placed in a single layer, and the distance between each billet is greater than or equal to 100mm. The billet must be padded with refractory bricks, and the height of the padded height is greater than or equal to 100mm.

[0068] See also Figure 2 In an exemplary embodiment, the second processing portion of the blank is soft-wrapped once and the blank is heated in the above step S120, which includes the following steps:

[0069] S121, performing a soft coating on the second processed part of the blank.

[0070] The second processing part of the blank can be soft-wrapped with two layers of aluminum silicate fiber felt and a thermocouple. The second processing part of the blank can be soft-wrapped so that when the blank is heated, the second processing part is insulated from the temperature by the soft wrapping and is not heated to the final forging temperature. After the first processing part of the blank reaches the final forging temperature, the first processing part is stretched to ensure that the second processing part does not deform, thereby improving the uniformity of the structure.

[0071] S122, heating the blank after the soft packaging to a first threshold temperature, and keeping the blank warm for a first threshold time.

[0072] Exemplarily, the first threshold temperature may be 850° C., and the first threshold time may be calculated as 1.0 min / mm.

[0073] S123, heating the blank that has been kept warm for the first threshold time to a second threshold temperature, and keeping the blank warm for the second threshold time.

[0074] Exemplarily, the second threshold temperature may be 970° C., and the second threshold time may be calculated as 0.8 min / mm.

[0075] S124, heating the blank that has been kept warm for the second threshold time to a third threshold temperature, and keeping the blank warm for the third threshold time.

[0076] Exemplarily, the third threshold temperature may be 1000° C., and the third threshold time may be calculated as 0.5 min / mm.

[0077] By heating the billet and then keeping it warm through the above steps S122 and S123, when the billet is heated to the third threshold temperature, the center and edge of the billet can evenly reach the third threshold temperature. In the above step S124, when the billet is evenly heated to the third threshold temperature, the billet continues to be kept warm, so that the heating of the billet is more uniform and reaches the third threshold temperature, providing a good temperature basis for the subsequent secondary soft-wrapping of the billet and then keeping it warm. It should be noted that the above threshold temperatures and threshold durations are only exemplary and do not constitute a limitation on the present application, as long as the first threshold temperature < the second threshold temperature < the third threshold temperature, the first threshold duration > the second threshold duration > the third threshold duration, and the final forging temperature is greater than or equal to 930°C.

[0078] S130, stretching the first processed portion of the heat-insulated blank.

[0079] In an exemplary embodiment, the step S130 of stretching the first processed portion of the heat-insulated billet may include: preheating a die of a high-speed forging machine; and stretching the first processed portion of the heat-insulated billet using the high-speed forging machine.

[0080] Specifically, a 31.5MN fast forging machine can be used to stretch the first processing part of the billet. Before the billet is stretched, the upper and lower dies of the 31.5MN fast forging machine are preheated for no less than two hours, the billet after heat preservation is transferred out of the high-temperature electric furnace, and then the first processing part of the billet is stretched by the 31.5MN fast forging machine. After the stretching process is completed, the billet is air-cooled. Among them, the transfer time of the billet out of the high-temperature electric furnace shall not exceed 45 seconds, and the downward pressure of the 31.5MN fast forging machine is less than or equal to 50mm each time.

[0081] If an equipment failure occurs during the forging process, causing the billet to be kept warm for more than 90 minutes in the above step S120, the temperature of the high-temperature electric furnace should be lowered to the first threshold temperature to keep the billet warm. After the failure is eliminated, the high-temperature electric furnace should be quickly heated to the third threshold temperature to halve the billet's keeping time. If the high-temperature electric furnace is lowered to the first threshold temperature to keep the billet warm for more than 120 minutes, the billet should be removed from the high-temperature electric furnace for air cooling.

[0082] S140, performing a first soft-wrapping on the first processed portion of the drawn blank and heating the blank, performing a second soft-wrapping on the heated blank and keeping the blank warm for a second preset time.

[0083] See also Figure 3 In an exemplary embodiment, the step S140 of soft-wrapping the first processed portion of the drawn blank and heating the blank may include the following steps:

[0084] S141, performing a soft packaging on the first processing part of the blank.

[0085] The first processing part of the blank can be soft-wrapped with two layers of aluminum silicate fiber felt and a thermocouple. The first processing part of the blank can be soft-wrapped so that when the blank is heated, the first processing part is insulated from the temperature by the soft wrapping and is not heated to the final forging temperature. After the second processing part of the blank reaches the final forging temperature, the second processing part is die-forged to ensure that the first processing part does not deform, thereby improving the uniformity of the structure.

[0086] S142, heating the blank after the soft packaging to a first threshold temperature, and keeping the blank warm for a first threshold time.

[0087] Exemplarily, the first threshold temperature may be 850° C., and the first threshold time may be calculated as 1.0 min / mm.

[0088] S143, heating the blank that has been kept warm for the first threshold time to a second threshold temperature, and keeping the blank warm for the second threshold time.

[0089] Exemplarily, the second threshold temperature may be 970° C., and the second threshold time may be calculated as 0.8 min / mm.

[0090] S144, heating the blank that has been kept warm for the second threshold time to a third threshold temperature, and keeping the blank warm for the third threshold time.

[0091] Exemplarily, the third threshold temperature may be 1000° C., and the third threshold time may be calculated as 0.5 min / mm.

[0092] By heating the billet and then keeping it warm through the above steps S142 and S143, when the billet is heated to the third threshold temperature, the center and edge of the billet can evenly reach the third threshold temperature. In the above step S144, when the billet is evenly heated to the third threshold temperature, the billet continues to be kept warm, so that the heating of the billet is more uniform and reaches the third threshold temperature, providing a good temperature basis for the subsequent secondary soft wrapping of the billet and then keeping it warm. It should be noted that the above threshold temperatures and threshold durations are only exemplary and do not constitute limitations on the present application, as long as the first threshold temperature < the second threshold temperature < the third threshold temperature, the first threshold duration > the second threshold duration > the third threshold duration, and the final forging temperature is greater than or equal to 930°C. Fig. 9 As shown, Fig. 9 Schematic diagram of the temperature field simulation of the billet during die forging.

[0093] If an equipment failure occurs during the forging process, causing the billet to be kept warm for more than 90 minutes in the above step S140, the temperature of the high-temperature electric furnace should be lowered to the first threshold temperature to keep the billet warm. After the failure is eliminated, the high-temperature electric furnace should be quickly heated to the third threshold temperature to halve the keeping time of the billet. If the high-temperature electric furnace is lowered to the first threshold temperature to keep the billet warm for more than 120 minutes, the billet should be removed from the high-temperature electric furnace for air cooling.

[0094] Specifically, in the above step S140, the blank is heated by a high-temperature electric furnace, and the temperature uniformity of the high-temperature electric furnace can be ±10°C. The first processing part of the blank is soft-wrapped with two layers of aluminum silicate fiber felt and a thermocouple. After the first processing part is tightly wrapped, the blank is heated by a high-temperature electric furnace. After heating to the final insulation time, the blank is removed from the high-temperature electric furnace, and the blank is soft-wrapped with aluminum silicate fiber felt and a high-temperature alloy binder for a second time, and the blank is placed in the high-temperature electric furnace for insulation for 30 minutes. Among them, the blank must be placed in the temperature control qualified area of ​​the high-temperature electric furnace, and the furnace of the high-temperature electric furnace should be swept forward before heating the blank. The blank is placed in the high-temperature electric furnace according to the ingot section number, and the placement position of each blank is recorded, and the blank must be placed in a single layer, and the distance between each blank is greater than or equal to 100mm. The blank must be padded with refractory bricks, and the height of the padded is greater than or equal to 100mm.

[0095] S150. Forging the blank using a combination die, wherein the lower die of the combination die has a first die cavity and a second die cavity, and the upper die of the combination die has a protrusion matched with the second die cavity. When forging the blank, the first processing part is placed in the first die cavity, the upper die applies pressure to the second processing part, and the protrusion extrude the second processing part to obtain a turbine rear shaft forging.

[0096] The lower mold of the combined mold provided in this embodiment has a first mold cavity and a second mold cavity, and the upper mold of the combined mold has a protrusion adapted to the second mold cavity. By optimizing the design of the combined mold, the shape of the turbine rear shaft forging is effectively adjusted. The weight of the bar stock required for the traditional turbine rear shaft forging preparation method is 900kg, while in this application, by optimizing the design of the combined mold, the weight of the bar stock required is 850kg. Finally, the usage of the raw material of the turbine rear shaft forging is reduced by 50kg, thereby reducing the production cost.

[0097] In an exemplary embodiment, if Figure 4 and Figure 6 As shown, the die forging of the blank using the combined die in the above step S150 may include the following steps:

[0098] S151. When the zero point distance is within a first threshold range, the pressing speed of the upper mold is controlled to be a first threshold speed.

[0099] Exemplarily, the first threshold range may be 950-470 mm, and the first threshold speed may be 110 mm / s.

[0100] S152: When the zero point distance is within the second threshold range, the pressing speed of the upper mold is controlled to be the second threshold speed.

[0101] Exemplarily, the second threshold range may be 470-170 mm, and the second threshold speed may be 5 mm / s.

[0102] S153: When the zero point distance is within the third threshold range, the pressing speed of the upper mold is controlled to be the third threshold speed.

[0103] Exemplarily, the third threshold range may be 170-105 mm (underpressure 3 mm), and the third threshold speed may be 1 mm / s.

[0104] The zero point distance is the distance between the end surface of the upper die close to the lower die and the end surface of the lower die close to the upper die.

[0105] The die forging of the blank is completed through the above steps S151, S152 and S153, which can protect the stable deformation of the blank during the die forging process and finally form a turbine rear shaft forging with good structural uniformity.

[0106] Exemplarily, a 400MN hydraulic press can be used to die forge the billet, and the upper and lower dies of the combined die are preheated before the billet is die forged. The preheating time is greater than or equal to 12 hours, and the preheating temperature is 300°C to 350°C, so as to prevent the combined die from contacting the billet due to the low temperature of the combined die when the billet is die forged, and a cold film layer is formed on the billet surface, thereby affecting the microstructure and properties of the turbine rear shaft forging. After preheating the combined die, the billet is die forged according to the above steps S151, S152 and S153, the first processing part is placed in the first die cavity, the upper die applies pressure to the second processing part, and the raised part squeezes the second processing part to obtain the turbine rear shaft forging. It should be noted that when the billet is transferred from the high-temperature electric furnace to the combined die, the transfer time of the billet cannot be greater than 30 seconds. At the same time, the combined die needs to be lubricated with water-based graphite before the billet is die forged.

[0107] See also Fig.10 , Fig.10 It is a schematic diagram of the ultimate pressing load of the hydraulic press forging the billet; wherein, Workpiece is the overall ultimate pressing load of the hydraulic press forging the billet, Top Die is the ultimate pressing load of the hydraulic press forging the second processing part of the billet, and Bottom Die is the ultimate pressing load of the hydraulic press forging the first processing part of the billet.

[0108] In an exemplary embodiment, after the raised portion extrude the second processed portion to obtain the turbine rear shaft forging, the method may further include: processing a test ring on the end face of the turbine rear shaft forging corresponding to the second die cavity and facing away from the upper die; performing solid solution treatment on the turbine rear shaft forging; and performing solid solution treatment and aging treatment on the test ring.

[0109] Specifically, after the turbine rear shaft forging is put into the furnace, the holding time starts to be calculated when all instruments reach the holding temperature of -3°C. The turbine rear shaft forging is subjected to solution treatment at 975°C±10°C. After holding for 1 hour, the turbine rear shaft forging is air-cooled or other methods are adopted to cool the turbine rear shaft forging faster.

[0110] More specifically, after the test ring is put into the furnace, the holding time starts to be calculated when all instruments reach the holding temperature of -3°C. The test ring is subjected to solution treatment at 975°C±10°C. After holding for 1 hour, the test ring is air-cooled or other methods are adopted to cool the test ring faster. The test ring is subjected to aging treatment, the test environment is kept at 720°C±10°C for 8 hours±15 minutes, the high-temperature electric furnace is cooled to 620°C±10°C at a rate of (50±10)°C / h, the test environment is kept at 8 hours±15 minutes, and finally the test ring is air-cooled.

[0111] Among them, the turbine rear shaft forgings and test rings are placed in a high-temperature electric furnace (furnace temperature uniformity ±10℃) in the temperature control qualified area, the furnace is cleaned before heating, the furnace is loaded according to the ingot section number, and the loading position is recorded. They are placed in a single layer, and the material spacing is ≥50mm.

[0112] The embodiment of the present application also provides sampling physical and chemical testing for the turbine rear shaft forging forged based on the above method.

[0113] Regarding the physical and chemical testing standards and sampling methods for turbine rear shaft forgings, this embodiment follows the inspection standards of "GH4169 Alloy Power Turbine Rear Shaft Forging Development and Ordering Technical Agreement" and "High-Quality GH4169 Alloy Low-Pressure Turbine Shaft Forgings".

[0114] The sampling method is as follows: the supplier shall conduct physical and chemical tests on the trial batch forgings on the forgings located at or equivalent to the head of the ingot, and the dissected pieces shall not be rough-machined; the supplier shall conduct physical and chemical tests on 1 / 2 of the dissected pieces, and the other 1 / 2 of the dissected pieces shall be marked with corresponding marks and sent to the buyer for re-inspection along with the batch of forgings;

[0115] For example, Figure 7 As shown, the test ring 740 is a first test ring S1 obtained by sampling in the chord direction of the forging, and the mechanical properties, high multiple and hardness of the first test ring S1 are sampled;

[0116] like Figure 8 As shown, sampling is performed in the axial direction of the forging to obtain a second test ring S2, wherein the length of the second test ring S2 cannot be less than 100 mm, the diameter of the second test ring S2 is 240 mm, and the mechanical properties, high multiple and hardness of the second test ring S2 are sampled.

[0117] The obtained turbine rear shaft forging was subjected to physical and chemical tests to verify that the forging obtained by the technical solution of this application meets the performance requirements. The specific test data are as follows:

[0118] Room temperature mechanical properties:

[0119]

[0120] Under 650℃ high temperature stretching:

[0121]

[0122] Among them, the macrostructure has no visible metallurgical defects such as looseness, pinholes, shrinkage holes, segregation, slag inclusions and inclusions, and there are no dark corrosion areas, white spots and shallow corrosion areas, which is qualified; the macrostructure of the lower surface of the corrosion has no metallurgical defects such as looseness, pinholes, shrinkage holes, segregation, slag inclusions and inclusions, which is qualified; after the forgings are processed according to the drawings, they are subjected to water immersion ultrasonic flaw detection piece by piece according to the AA grade requirements of HB / Z34-1998 to monitor whether there are defects inside the turbine rear shaft forgings, which meet the standard requirements and are qualified. It can be seen that the finished forgings are qualified. The test results of the macrostructure and grain size of the first test ring S1 and the second test ring S2 in this embodiment are shown in the attached figure. Fig.11 , 12 As shown, the power turbine rear shaft forging finally achieved a weight reduction of 50kg, and the grain size difference was controlled within 3 levels.

[0123] The present application also provides a turbine rear shaft forging, which is prepared based on the GH4169 alloy turbine rear shaft forging manufacturing method described in any of the above embodiments, such as Figure 7 As shown, the turbine rear shaft forging may include: a body portion 710 , a shaft portion 720 , a recessed portion 730 and a test ring 740 .

[0124] Among them, the main body 710 may include a first end face 711 and a second end face 712 arranged opposite to each other; the second end face 712 of the main body 710 partially extends along the axial direction of the main body 710 in a direction away from the first end face 711 to form an axis portion 720; the first end face 711 of the main body 710 partially recesses along the axial direction of the main body 710 in a direction close to the second end face 712 to form a recessed portion 730; and a test ring 740 is formed on the second end face 712 of the main body 710.

[0125] In an exemplary embodiment, the shaft portion 720 is a cylindrical structure, and the axes of the shaft portion 720, the main body portion 710, the recessed portion 730 and the test ring 740 coincide with each other; a rounded corner is provided at the position where the main body portion 710 and the shaft portion 720 are connected; the cross-section of the recessed portion 730 along a direction parallel to the first end face 711 is circular, and the cross-section along a direction perpendicular to the first end face 711 is an inverted trapezoid.

[0126] In this embodiment, the tensile strength of the obtained turbine rear shaft forging body is ≥1275MPa, the yield strength is ≥1035MPa, the elongation is ≥12%, the cross-sectional shrinkage is ≥15%, and the hardness is ≤277.

[0127] The above are only preferred embodiments of the present application, and are not intended to limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A method for manufacturing a GH4169 alloy turbine rear shaft forging, characterized in that: include: Grinding the surface of the bar; An annular dividing belt is processed along the circumferential direction on the side of the bar to obtain a blank, wherein the dividing belt divides the blank into a first processing portion and a second processing portion opposite to each other; Performing a soft wrapping on the second processing portion of the blank and heating the blank, performing a second soft wrapping on the heated blank and keeping the blank warm for a first preset time; Drawing the first processed portion of the blank after heat preservation; Performing a soft wrapping on the first processed portion of the drawn blank and heating the blank, performing a second soft wrapping on the heated blank and keeping the blank warm for a second preset time; The blank is die forged using a combination die, wherein the lower die of the combination die has a first die cavity and a second die cavity, and the upper die of the combination die has a protrusion adapted to the second die cavity. When the blank is die forged, the first processed part is placed in the first die cavity, the upper die applies pressure to the second processed part, and the protrusion extrude the second processed part to obtain a turbine rear shaft forging.

2. The method for manufacturing a GH4169 alloy turbine rear shaft forging according to claim 1, characterized in that: The method further comprises: Pre-treating the bar material to eliminate surface depressions of the bar material, and the ratio of the equivalent diameter to the depth of the surface depressions of the bar material is greater than or equal to a preset value; Accordingly, the grinding of the bar surface comprises: The pre-treated bar is ground.

3. The method for manufacturing a GH4169 alloy turbine rear shaft forging according to claim 1, characterized in that: The primary soft package is made of two layers of aluminum silicate fiber felt and a thermocouple, and the secondary soft package is made of aluminum silicate fiber felt and a high-temperature alloy binder.

4. The method for manufacturing a GH4169 alloy turbine rear shaft forging according to claim 1, characterized in that: The step of soft-wrapping the second processed portion of the blank and heating the blank comprises: Performing a soft coating on the second processed portion of the blank; The blank after the soft packaging is heated to a first threshold temperature, and the blank is kept warm for a first threshold time; Heating the blank after the first threshold time period of heat preservation to a second threshold temperature, and heat preserving the blank for the second threshold time period; Heating the blank that has completed the second threshold time period of heat preservation to a third threshold temperature, and heat preserving the blank for the third threshold time period; Among them, the first threshold duration>the second threshold duration>the third threshold duration.

5. The method for manufacturing a GH4169 alloy turbine rear shaft forging according to claim 1, characterized in that: The step of stretching the first processed portion of the blank after heat preservation comprises: Preheat the die of the fast forging machine; The fast forging machine is used to stretch the first processed portion of the blank after the insulation.

6. The method for manufacturing a GH4169 alloy turbine rear shaft forging according to claim 1, characterized in that: The method of soft-wrapping the first processed portion of the drawn blank and heating the blank comprises: Performing a soft coating on the first processed portion of the blank; The blank after the soft packaging is heated to a first threshold temperature, and the blank is kept warm for a first threshold time; Heating the blank after the first threshold time period of heat preservation to a second threshold temperature, and heat preserving the blank for the second threshold time period; The blank that has completed the second threshold time period of heat preservation is heated to a third threshold temperature, and the blank is kept warm for the third threshold time period.

7. The method for manufacturing a GH4169 alloy turbine rear shaft forging according to claim 1, characterized in that: The method of forging the blank by using a combined die comprises: When the zero point distance is within a first threshold range, controlling the pressing speed of the upper die to be the first threshold speed; When the zero point distance is within the second threshold range, controlling the pressing speed of the upper die to be the second threshold speed; When the zero point distance is within a third threshold range, controlling the pressing speed of the upper die to be a third threshold speed; The zero point distance is the distance between the end surface of the upper die close to the lower die and the end surface of the lower die close to the upper die.

8. The method for manufacturing a GH4169 alloy turbine rear shaft forging according to claim 1, characterized in that: After the raised portion extrude the second processed portion to obtain a turbine rear shaft forging, the method further includes: A test ring is machined on the end surface of the turbine rear shaft forging corresponding to the second die cavity and facing away from the upper die; performing a solid solution treatment on the turbine rear shaft forging; The test rings were subjected to solution treatment and aging treatment.

9. A turbine rear shaft forging, prepared based on the manufacturing method of GH4169 alloy turbine rear shaft forging according to any one of claims 1 to 8, characterized in that: include: The main body comprises a first end surface and a second end surface which are arranged opposite to each other; A shaft portion, wherein the second end surface portion of the main body portion extends in an axial direction of the main body portion in a direction away from the first end surface to form the shaft portion; A recessed portion, wherein the first end surface portion of the main body portion is recessed along the axial direction of the main body portion toward the second end surface to form the recessed portion; A test ring is formed on the second end surface of the main body.

10. The turbine rear shaft forging according to claim 9, characterized in that: The shaft portion is a cylindrical structure, and the axes of the shaft portion, the body portion, the recessed portion and the test ring coincide with each other; A rounded corner is provided at the position where the main body portion is connected to the shaft portion; The cross section of the recessed portion along a direction parallel to the first end surface is circular, and the cross section along a direction perpendicular to the first end surface is an inverted trapezoid.

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