A method for manufacturing a GH4169 alloy turbine rear axle forging and the turbine rear axle forging

Abstract

This application discloses a method for manufacturing a GH4169 alloy turbine rear axle forging and the turbine rear axle forging itself. The method includes: grinding the surface of a bar stock; machining an annular dividing strip along the circumferential direction on the side of the bar stock to obtain a billet; applying a soft sleeve to the second processing section of the billet and heating the billet; applying a second soft sleeve to the heated billet and holding the billet at temperature for a first preset time; drawing the first processing section of the held-temperature billet; applying a soft sleeve to the first processing section of the drawn billet and heating the billet; applying a second soft sleeve to the heated billet and holding the billet at temperature for a second preset time; and die forging the billet using a combined die to obtain the turbine rear axle forging. By drawing the first processing section of the billet using the above method, the uniformity of the microstructure is improved, and the grain size difference is reduced. By optimizing the design of the combined die, the shape of the forging is effectively adjusted, thereby reducing the amount of raw material used and lowering production costs.

Description

Technical Field

[0001] This application relates to the field of GH4169 alloy turbine rear axle forging technology, and in particular to a method for manufacturing GH4169 alloy turbine rear axle forging and a turbine rear axle forging. Background Technology

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

[0003] However, the manufacturing process of existing turbine rear axle forgings typically requires a large input of raw materials, resulting in significant material consumption and numerous complex processes. Furthermore, the forgings exhibit significant variations in longitudinal section thickness, making it extremely difficult to form the thicker section at the larger end. The lack of deformation at the smaller end of the forging affects the uniformity of its microstructure. Moreover, the forging and machining processes fail to fully utilize the material's properties, leading to increased material waste. Inhomogeneities in heat treatment and forging processes result in uneven internal microstructure distribution. This inhomogeneity not only affects the mechanical properties of the forgings but may also lead to fatigue failure in practical applications, thereby reducing product lifespan and safety. Summary of the Invention

[0004] The main objective of this application is to provide a manufacturing method for a GH4169 alloy turbine rear axle forging and a turbine rear axle forging, aiming to solve the technical problems of poor microstructure uniformity and high material consumption in turbine rear axle forgings.

[0005] To achieve the above objectives, this application provides a method for manufacturing a GH4169 alloy turbine rear axle forging. The method includes: grinding the surface of a bar stock; machining an annular dividing belt along the circumferential direction on the side of the bar stock to obtain a billet, wherein the dividing belt divides the billet into a first processing section and a second processing section; applying a soft sleeve to the second processing section of the billet and heating the billet; applying a second soft sleeve to the heated billet and holding the billet at a temperature for a first preset time; drawing the first processing section of the held-temperature billet; and then drawing the drawn portion of the billet... The billet is first soft-wrapped and heated in the first processing part, and then soft-wrapped again and kept warm for a second preset time after heating. The billet is then die-forged using a combined mold, wherein the lower mold of the combined mold 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. When die-forging the billet, the first processing part is placed in the first mold cavity, the upper mold applies pressure to the second processing part, and the protrusion extrudes the second processing part to obtain a turbine rear axle forging.

[0006] Optionally, the method further includes:

[0007] The bar stock is pretreated to eliminate surface depressions, and the ratio of the equivalent diameter to the depth of the surface depression is greater than or equal to a preset value.

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

[0009] The pre-treated bar stock is then polished.

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

[0011] Optionally, the step of applying a soft sleeve to the second processing section of the billet and heating the billet includes:

[0012] The second processing section of the blank is wrapped with a soft sleeve once;

[0013] The blank after one soft wrapping is heated to a first threshold temperature, and the blank is kept at that temperature for a first threshold duration;

[0014] The billet, after being held for the first threshold duration, is heated to the second threshold temperature, and then held for the second threshold duration.

[0015] The billet that has completed the second threshold temperature holding period is heated to the third threshold temperature, and the billet is held for the third threshold temperature holding period.

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

[0017] Optionally, the lengthening of the first processing section of the heat-insulated billet includes:

[0018] Preheat the mold of the high-speed forging machine;

[0019] The first processing section of the heat-insulated billet is lengthened using the high-speed forging machine.

[0020] Optionally, the first processing section of the drawn billet is subjected to a soft wrapping and the billet is heated, including:

[0021] The first processing section of the blank is wrapped with a soft sleeve once;

[0022] The blank after one soft wrapping is heated to a first threshold temperature, and the blank is kept at that temperature for a first threshold duration;

[0023] The billet, after being held for the first threshold duration, is heated to the second threshold temperature, and then held for the second threshold duration.

[0024] The billet, after being kept at the second threshold temperature for a duration of time, is heated to a third threshold temperature and then kept at the third threshold temperature for a duration of time.

[0025] Optionally, the forging of the billet using a combined die includes:

[0026] When the zero-point distance is within the first threshold range, the downward pressing speed of the upper mold is controlled to be the first threshold speed;

[0027] When the zero-point distance is within the second threshold range, the downward pressing speed of the upper mold is controlled to be the second threshold speed;

[0028] When the zero-point distance is within the third threshold range, the downward pressing speed of the upper mold is controlled to be the third threshold speed;

[0029] The zero-point distance is the distance between the end face of the upper mold near the lower mold and the end face of the lower mold near the upper mold.

[0030] Optionally, after the protrusion extrudes the second machining portion to obtain the turbine rear axle forging, the method further includes:

[0031] A test ring is machined on the end face of the turbine rear axle forging that corresponds to the second die cavity and is away from the upper die;

[0032] The turbine rear axle forging was subjected to solution treatment;

[0033] The test ring was subjected to solution treatment and aging treatment.

[0034] To achieve the above objectives, this application also provides a turbine rear axle forging, manufactured based on any of the above-described GH4169 alloy turbine rear axle forging manufacturing methods. The turbine rear axle forging includes: a body portion, a shaft portion, a recessed portion, and a test ring; wherein, the body portion includes a first end face and a second end face disposed opposite to each other; the second end face portion of the body portion extends along the axial direction of the body portion in a direction away from the first end face to form the shaft portion; the first end face portion of the body portion is recessed along the axial direction of the body portion 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 body portion.

[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;

[0036] The position where the body part connects to the shaft part is provided with a rounded corner;

[0037] The recessed portion has a circular cross-section along the direction parallel to the first end face, and an inverted trapezoidal cross-section along the direction perpendicular to the first end face.

[0038] This application discloses a method for manufacturing a GH4169 alloy turbine rear axle forging and the turbine rear axle forging itself. First, the surface of a bar stock is ground. A ring-shaped dividing belt is machined circumferentially on the side of the bar stock to obtain a billet, wherein the dividing belt divides the billet into a first processing section and a second processing section. Second, the second processing section of the billet is first soft-wrapped and heated. The heated billet is then soft-wrapped a second time and held at that temperature for a first preset time. The first processing section of the held-temperature billet is then drawn. This drawing deformation in the first processing section of the billet improves the microstructure. The existing undeformed structure is improved, and the grain size difference between the structure of the first processing part and the structure of the second processing part is reduced. Finally, the first processing part of the drawn billet is soft-wrapped once and the billet is heated. The heated billet is soft-wrapped a second time and held at a temperature for a second preset time. The billet is forged using a combined die, wherein the lower die of the combined die has a first die cavity and a second die cavity, and the upper die of the combined die has a protrusion adapted to the second die cavity. When forging the billet, the first processing part is placed in the first die cavity, the upper die applies pressure to the second processing part, and the protrusion extrudes the second processing part to obtain the turbine rear axle forging. By optimizing the design of the combined die, the shape of the turbine rear axle forging is effectively adjusted, thereby reducing the amount of raw materials used and lowering production costs. Attached Figure Description

[0039] Figure 1 A schematic flowchart illustrating the manufacturing method of the GH4169 alloy turbine rear axle forging provided in this application embodiment;

[0040] Figure 2 This is a schematic diagram illustrating the process of applying a soft sleeve to the second processing section of the billet and heating the billet according to an embodiment of this application;

[0041] Figure 3 This is a schematic diagram illustrating the process of applying a soft sleeve to the first processing section of the drawn billet and heating the billet according to an embodiment of this application;

[0042] Figure 4 This is a schematic diagram illustrating the process of die forging a billet using a combined mold, as described in an embodiment of this application.

[0043] Figure 5 This is a schematic diagram simulating the elongation of the first processing section of the heat-insulated billet according to an embodiment of this application;

[0044] Figure 6 This is a schematic diagram simulating the forging of a billet using a combined mold, as described in an embodiment of this application.

[0045] Figure 7 This is a schematic diagram of the turbine rear axle forging structure provided in an embodiment of this application;

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

[0047] Figure 9 This is a schematic diagram simulating the temperature field of the billet during die forging.

[0048] Figure 10 This is a schematic diagram of the ultimate pressing load of a hydraulic press for die forging a billet.

[0049] Figure 11 This is a high-magnification image showing the microstructure and grain size of the first test ring S1;

[0050] Figure 12 This is a high-magnification image showing the microstructure and grain size 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 the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0052] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0053] It should be noted that all directional indicators (such as up, down, left, right, front, back, etc.) in the embodiments of this application are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicator will also change accordingly.

[0054] In this application, unless otherwise expressly specified and limited, the terms "connection," "fixed," etc., should be interpreted broadly. For example, "fixed" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0055] Furthermore, if the embodiments of this application involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the meaning of "and / or" throughout the text includes three parallel solutions; for example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed in this application.

[0056] The present application will now be described in detail with reference to the accompanying drawings and embodiments.

[0057] Figure 1 This is a schematic flowchart illustrating the manufacturing method of the GH4169 alloy turbine rear axle forging provided in an embodiment of this application. Figure 2 This is a schematic diagram illustrating the process of performing a soft wrapping and heating of the billet in the second processing section according to an embodiment of this application. Figure 3 This is a schematic diagram illustrating the process of applying a soft sleeve to the first processing section of the drawn billet and heating the billet according to an embodiment of this application. Figure 4 This is a schematic diagram illustrating the process of die forging a billet using a combined mold, as described in an embodiment of this application. Figure 5 This is a schematic diagram simulating the elongation of the first processing section of the heat-insulated billet according to an embodiment of this application. Figure 6 This is a schematic diagram simulating the forging of a billet using a combined die, as described in an embodiment of this application. Figure 7 This is a schematic diagram of the turbine rear axle forging structure provided in an embodiment of this application. Figure 8 This is a schematic diagram of the structure of the second test ring S2 in this application. Figure 9 This is a schematic diagram simulating the temperature field of the billet during die forging. Figure 10 This is a schematic diagram of the ultimate pressing load of a hydraulic press for die forging a billet. Figure 11 This is a high-magnification image showing the microstructure and grain size of the first test ring S1. Figure 12 This is a high-magnification image showing the microstructure and grain size of the second test ring S2.

[0058] This application provides a method for manufacturing a GH4169 alloy turbine rear axle forging, such as... Figures 1-6 As shown, the method includes the following specific steps:

[0059] S110. Grind the surface of the bar stock.

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

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

[0062] Further, an annular dividing belt is machined circumferentially on the side of the bar stock to obtain a billet, wherein the dividing belt divides the billet into a first processing section and a second processing section, so as to facilitate subsequent forging of the billet.

[0063] S120. The second processing section of the billet is first wrapped with a soft sleeve and the billet is heated. The heated billet is then wrapped with a soft sleeve again and kept warm for a first preset time.

[0064] In an exemplary embodiment, the primary soft sheathing can be achieved by using two layers of aluminum silicate fiber felt and a thermocouple, while the secondary soft sheathing can be achieved by using aluminum silicate fiber felt and a high-temperature alloy adhesive. Specifically, the secondary soft sheathing can be applied to both the first and second processing sections simultaneously to achieve heat preservation of the entire billet.

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

[0066] For another example, the heating equipment for heating the billet can be a high-temperature electric furnace. The temperature uniformity of the high-temperature electric furnace can be ±10℃, and the first preset time can be 30 minutes. It should be noted that the preset time is at least 30 minutes, but can also be more than 30 minutes. After the billet is subjected to a second soft wrapping, it is placed in the high-temperature electric furnace and held at that temperature for 30 minutes. This ensures that the billet has a forging temperature when it is drawn in the second processing section, facilitating the drawing process.

[0067] Specifically, the second processing section of the 770mm long billet is first softly wrapped with two layers of aluminosilicate fiber felt and a thermocouple. After the second processing section is tightly wrapped, the billet is heated in a high-temperature electric furnace. After the final holding time, the billet is removed from the high-temperature electric furnace and then softly wrapped again with aluminosilicate fiber felt and high-temperature alloy binder. The billet is then placed back into the high-temperature electric furnace for a holding time of 30 minutes. The billet must be placed within the temperature-controlled zone of the high-temperature electric furnace. Before heating the billet, the furnace chamber should be pre-swept. The billets are placed in the high-temperature electric furnace according to their ingot section numbers, and the placement position of each billet is recorded. The billets must be placed in a single layer, with a distance of at least 100mm between each billet. Refractory bricks must be used to elevate the billets, with a height of at least 100mm.

[0068] Please see Figure 2 In an exemplary embodiment, step S120, which involves applying a soft sleeve to the second processing section of the blank and heating the blank, includes the following steps:

[0069] S121. Perform a soft wrapping on the second processing section of the billet.

[0070] The second processing section of the billet can be softly sheathed using two layers of aluminum silicate fiber felt and a thermocouple. This soft sheathing prevents the second processing section from heating up to the final forging temperature during the heating process. Furthermore, after the first processing section reaches its final forging temperature, the second processing section remains undeformed during the drawing process, thus improving the uniformity of the microstructure.

[0071] S122. Heat the billet after one soft wrapping to the first threshold temperature, and keep the billet warm for the first threshold time.

[0072] For example, the first threshold temperature can be 850°C, and the first threshold duration can be calculated at 1.0 min / mm.

[0073] S123. Heat the billet that has completed the first threshold time of heat preservation to the second threshold temperature, and heat the billet for the second threshold time.

[0074] For example, the second threshold temperature can be 970°C, and the second threshold duration can be calculated at 0.8 min / mm.

[0075] S124. Heat the billet that has completed the second threshold time of heat preservation to the third threshold temperature, and heat the billet for the third threshold time.

[0076] For example, the third threshold temperature can be 1000℃, and the third threshold duration can be calculated at 0.5 min / mm.

[0077] By heating the billet and then holding it at that temperature in steps S122 and S123, the center and edges of the billet can reach the third threshold temperature uniformly when heated to that temperature. Step S124, which involves holding the billet at that temperature after it has uniformly reached the third threshold temperature, further ensures more uniform heating and ensures the billet reaches the third threshold temperature, providing a good temperature basis for subsequent secondary soft-sheathing and holding. It should be noted that the threshold temperatures and durations described above are merely illustrative and do not constitute a limitation of this 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, it is acceptable.

[0078] S130, The first processing section of the heat-insulated billet is lengthened.

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

[0080] Specifically, a 31.5MN high-speed forging mill can be used to elongate the first processing section of the billet. Before elongation, the upper and lower dies of the 31.5MN high-speed forging mill should be preheated for no less than two hours. After preheating, the billet is transferred out of the high-temperature electric furnace, and then elongated through the first processing section of the 31.5MN high-speed forging mill. After elongation, the billet is air-cooled. The transfer time of the billet out of the high-temperature electric furnace should not exceed 45 seconds, and the downward pressure of the 31.5MN high-speed forging mill each time should be less than or equal to 50mm.

[0081] If a fault occurs during the forging process, causing the billet to be held at the temperature in step S120 for more than 90 minutes, the temperature of the high-temperature electric furnace should be reduced to the first threshold temperature to hold the billet. After the fault is cleared, the high-temperature electric furnace should be rapidly heated to the third threshold temperature, and the holding time for the billet should be halved. If the time for holding the billet at the first threshold temperature exceeds 120 minutes, the billet should be removed from the high-temperature electric furnace and air-cooled.

[0082] S140. The first processing section of the drawn billet is wrapped with a soft sleeve and heated. The heated billet is wrapped with a soft sleeve a second time and kept warm for a second preset time.

[0083] Please see Figure 3 In an exemplary embodiment, the step S140 above, which involves applying a soft sleeve to the first processing section of the drawn blank and heating the blank, may include the following steps:

[0084] S141. The first processing section of the billet is wrapped with a soft sleeve.

[0085] The first processing section of the billet can be softly sheathed using two layers of aluminum silicate fiber felt and a thermocouple. This soft sheathing prevents the first processing section from heating up to the final forging temperature during the heating process. Furthermore, when the second processing section reaches the final forging temperature, the first processing section remains undeformed during die forging, thus improving the uniformity of the microstructure.

[0086] S142. Heat the billet after one soft wrapping to the first threshold temperature, and keep the billet warm for the first threshold time.

[0087] For example, the first threshold temperature can be 850°C, and the first threshold duration can be calculated at 1.0 min / mm.

[0088] S143. Heat the billet that has completed the first threshold time of heat preservation to the second threshold temperature, and heat the billet for the second threshold time.

[0089] For example, the second threshold temperature can be 970°C, and the second threshold duration can be calculated at 0.8 min / mm.

[0090] S144. Heat the billet that has completed the second threshold time of heat preservation to the third threshold temperature, and heat the billet for the third threshold time.

[0091] For example, the third threshold temperature can be 1000℃, and the third threshold duration can be calculated at 0.5 min / mm.

[0092] By heating the billet and then holding it at that temperature in steps S142 and S143, the center and edges of the billet can uniformly reach the third threshold temperature when it is heated to that temperature. Step S144 further holds the billet at that temperature to ensure even heating and ensure it reaches the third threshold temperature, providing a good temperature basis for subsequent secondary soft-sheathing and holding. It should be noted that the threshold temperatures and durations described above are merely illustrative and do not constitute a limitation of this 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, it is acceptable. Figure 9 As shown, Figure 9 This is a schematic diagram simulating the temperature field of the billet during die forging.

[0093] If a fault occurs during the forging process, causing the billet to be held at the temperature for more than 90 minutes in step S140, the temperature of the high-temperature electric furnace should be reduced to the first threshold temperature to hold the billet. After the fault is cleared, the high-temperature electric furnace should be rapidly heated to the third threshold temperature, and the holding time for the billet should be halved. If the time for holding the billet at the first threshold temperature exceeds 120 minutes, the billet should be removed from the high-temperature electric furnace and air-cooled.

[0094] Specifically, in step S140 above, the billet is heated using a high-temperature electric furnace, with a furnace temperature uniformity of ±10℃. The first processing section of the billet is softly wrapped with two layers of aluminosilicate fiber felt and a thermocouple. After the first processing section is tightly wrapped, the billet is heated in the high-temperature electric furnace. After the final holding time, the billet is removed from the high-temperature electric furnace and softly wrapped again with aluminosilicate fiber felt and a high-temperature alloy binder. The billet is then placed back into the high-temperature electric furnace for a holding time of 30 minutes. The billet must be placed within the temperature-controlled zone of the high-temperature electric furnace. Before heating the billet, the furnace chamber should be pre-swept. The billets are placed in the high-temperature electric furnace according to their ingot section numbers, and the placement position of each billet is recorded. The billets must be placed in a single layer, with a distance of at least 100mm between each billet. Refractory bricks must be used to elevate the billets, with a height of at least 100mm.

[0095] S150. A combination mold is used to forge a billet. 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 protrusion that matches the second mold cavity. When forging the billet, the first processing part is placed into the first mold cavity, the upper mold applies pressure to the second processing part, and the protrusion extrudes the second processing part to obtain a turbine rear axle forging.

[0096] The combined mold provided in this embodiment has a first mold cavity and a second mold cavity in the lower mold, and a protrusion adapted to the second mold cavity in the upper mold. By optimizing the design of the combined mold, the shape of the turbine rear axle forging is effectively adjusted. The traditional method of preparing turbine rear axle forging requires a bar stock weight of 900 kg, while this application, through optimizing the design of the combined mold, requires a bar stock weight of 850 kg. Ultimately, the amount of raw material used for turbine rear axle forging is reduced by 50 kg, thereby reducing production costs.

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

[0098] S151. When the zero-point distance is within the first threshold range, control the downward pressing speed of the upper mold to the first threshold speed.

[0099] For example, the first threshold range can be 950 to 470 mm, and the first threshold speed can be 110 mm / s.

[0100] S152. When the zero-point distance is within the second threshold range, control the downward pressing speed of the upper mold to the second threshold speed.

[0101] For example, the second threshold range can be 470 to 170 mm, and the second threshold speed can be 5 mm / s.

[0102] S153. When the zero-point distance is within the third threshold range, control the downward pressing speed of the upper mold to the third threshold speed.

[0103] For example, the third threshold range can be 170-105mm (undervoltage 3mm), and the third threshold speed can be 1mm / s.

[0104] The zero-point distance is the distance between the end face of the upper mold closest to the lower mold and the end face of the lower mold closest to the upper mold.

[0105] By completing the die forging of the billet through the above steps S151, S152 and S153, the billet can be protected from stable deformation during the die forging process, and finally a turbine rear axle forging with good microstructure uniformity can be formed.

[0106] For example, a 400MN hydraulic press can be used for die forging the billet. Before die forging, the upper and lower dies of the combined mold are preheated for at least 12 hours at a temperature of 300℃ to 350℃ to prevent the formation of a cold film on the billet surface due to low mold temperature during die forging, which could affect the microstructure and properties of the turbine rear axle forging. After preheating the combined mold, the billet is forged according to 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 protrusion extrudes the second processing part to obtain the turbine rear axle forging. It should be noted that when transferring the billet from the high-temperature electric furnace to the combined mold, the transfer time should not exceed 30 seconds. Furthermore, the combined mold needs to be lubricated with water-based graphite before die forging.

[0107] Please see Figure 10 , Figure 10 This is a schematic diagram of the ultimate pressing load of a hydraulic press forging a billet; where Workpiece represents the overall ultimate pressing load of the hydraulic press forging the billet, Top Die represents the ultimate pressing load of the hydraulic press forging the billet in the second processing section, and Bottom Die represents the ultimate pressing load of the hydraulic press forging the billet in the first processing section.

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

[0109] Specifically, after the turbine rear axle forging is placed in the furnace, the holding time is calculated when all instruments reach the holding temperature of -3℃. The turbine rear axle forging is then subjected to solution treatment at 975℃±10℃, held for 1 hour, and then air-cooled or subjected to other methods for faster cooling.

[0110] More specifically, after the test ring is placed in the furnace, the holding time is calculated when all instruments reach the holding temperature of -3℃. The test ring is then subjected to solution treatment at 975℃±10℃, held for 1 hour, and then air-cooled or cooled more quickly using other methods. The test ring is then subjected to aging treatment, with the test ring held at 720℃±10℃ for 8 hours±15 minutes, the high-temperature electric furnace is cooled to 620℃±10℃ at a rate of (50±10)℃ / h, the test ring is then held at 720℃±10℃ for 8 hours±15 minutes, and finally air-cooled.

[0111] The turbine rear axle forging and test ring are placed in a high-temperature electric furnace (furnace temperature uniformity ±10℃) within a temperature-controlled zone. The furnace chamber is cleaned before heating, and the furnace is loaded according to the ingot section number. The loading position is recorded, and the materials are placed in a single layer with a spacing of ≥50mm.

[0112] This application also provides sampling physicochemical testing for turbine rear axle forgings forged using the above method.

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

[0114] The sampling method is as follows: the physical and chemical tests of the trial batch of forgings shall be carried out by the supplier on the forging located at or equivalent to the head of the ingot, and the cut parts shall not be rough-machined; the supplier shall carry out physical and chemical tests on 1 / 2 of the cut parts, and mark the other 1 / 2 of the cut parts with the corresponding marks and send them to the buyer for retesting along with the batch of forgings.

[0115] For example, such as Figure 7 As shown, the first test ring S1 is obtained by sampling the chord direction of the forging in test ring 740, and the mechanical properties, magnification, and hardness of the first test ring S1 are sampled.

[0116] like Figure 8 As shown, a second test ring S2 is obtained by sampling along the axial direction of the forging. The length of the second test ring S2 is not less than 100 mm, and the diameter of the second test ring S2 is 240 mm. The mechanical properties, magnification, and hardness of the second test ring S2 are also sampled.

[0117] The obtained turbine rear axle 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 high temperature stretching at 650℃:

[0121]

[0122] Among them, the low-magnification microstructure showed no visible metallurgical defects such as porosity, pinholes, shrinkage cavities, segregation, slag inclusions, and impurities, and there were no dark corrosion areas, white spots, or shallow corrosion areas, thus it was qualified; the low-magnification microstructure of the corroded surface showed no metallurgical defects such as porosity, pinholes, shrinkage cavities, segregation, slag inclusions, and impurities, thus it was qualified; after the forgings were processed according to the drawings, each piece was subjected to water immersion ultrasonic testing according to the AA grade requirements of HB / Z34-1998 to monitor for internal defects in the turbine rear axle forgings, and it met the standard requirements, thus it was qualified. It can be seen that the finished forgings were qualified. The test results of the high-magnification microstructure and grain size of the first test ring S1 and the second test ring S2 in this embodiment are attached. Figure 11 , 12 As shown, the final power turbine rear axle forging achieved a weight reduction of 50kg, and the grain size difference was controlled within level 3.

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

[0124] The body portion 710 may include a first end face 711 and a second end face 712 disposed opposite to each other; the second end face 712 portion of the body portion 710 extends along the axial direction of the body portion 710 in a direction away from the first end face 711 to form a shaft portion 720; the first end face 711 portion of the body portion 710 is recessed along the axial direction of the body portion 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 body portion 710.

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

[0126] In this embodiment, the obtained turbine rear axle forging has a tensile strength ≥1275MPa, yield strength ≥1035MPa, elongation ≥12%, reduction of area ≥15%, and hardness ≤277.

[0127] The above are merely preferred embodiments of this application and do not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. A method for manufacturing a GH4169 alloy turbine rear axle forging, characterized in that, include: Grind the surface of the bar stock; A ring-shaped dividing belt is machined circumferentially on the side of the bar stock to obtain a blank, wherein the dividing belt divides the blank into a first processing section for forming a shaft portion and a second processing section for forming a head region with a recessed portion. The second processing section of the blank is subjected to a soft wrapping and the blank is heated, including: The second processing section of the blank is wrapped with a soft sleeve once; The blank after one soft wrapping is heated to a first threshold temperature, and the blank is kept at that temperature for a first threshold duration; The billet, after being held for the first threshold duration, is heated to the second threshold temperature, and then held for the second threshold duration. The billet that has completed the second threshold temperature holding period is heated to the third threshold temperature, and the billet is held for the third threshold temperature holding period. Wherein, the duration of the first threshold > the duration of the second threshold > the duration of the third threshold; The heated billet is then subjected to a second soft wrapping and kept at a temperature for a first preset time; the first processing section of the kept-temperature billet is then lengthened. The first processing section of the drawn billet is first wrapped with a soft sleeve and heated. The heated billet is then wrapped with a soft sleeve a second time and kept warm for a second preset time. The billet is forged using a combination mold, wherein the lower mold of the combination mold has a first cavity for accommodating the first processing part and a second cavity for forming the second processing part, and the upper mold of the combination mold has a protrusion adapted to the second cavity. When forging the billet, the first processing part is placed into the first cavity, the upper mold applies pressure to the second processing part, and the protrusion extrudes the second processing part to obtain a turbine rear axle forging.

2. The method for manufacturing the GH4169 alloy turbine rear axle forging according to claim 1, characterized in that, The method further includes: The bar stock is pretreated to eliminate surface depressions, and the ratio of the equivalent diameter to the depth of the surface depression is greater than or equal to a preset value. Accordingly, the grinding of the bar surface includes: The pre-treated bar stock is then polished.

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

4. The method for manufacturing the GH4169 alloy turbine rear axle forging according to claim 1, characterized in that, The process of elongating the first processing section of the heat-insulated billet includes: Preheat the mold of the high-speed forging machine; The first processing section of the heat-insulated billet is lengthened using the high-speed forging machine.

5. The method for manufacturing the GH4169 alloy turbine rear axle forging according to claim 1, characterized in that, The first processing section of the drawn billet is subjected to a soft wrapping and heating, including: The first processing section of the blank is wrapped with a soft sleeve once; The blank after one soft wrapping is heated to a first threshold temperature, and the blank is kept at that temperature for a first threshold duration; The billet, after being held for the first threshold duration, is heated to the second threshold temperature, and then held for the second threshold duration. The billet, after being kept at the second threshold temperature for a duration of time, is heated to a third threshold temperature and then kept at the third threshold temperature for a duration of time.

6. The method for manufacturing the GH4169 alloy turbine rear axle forging according to claim 1, characterized in that, The process of forging the billet using a combination mold includes: When the zero-point distance is within the first threshold range, the downward pressing speed of the upper mold is controlled to be the first threshold speed; When the zero-point distance is within the second threshold range, the downward pressing speed of the upper mold is controlled to be the second threshold speed; When the zero-point distance is within the third threshold range, the downward pressing speed of the upper mold is controlled to be the third threshold speed; The zero-point distance is the distance between the end face of the upper mold near the lower mold and the end face of the lower mold near the upper mold.

7. The method for manufacturing the GH4169 alloy turbine rear axle forging according to claim 1, characterized in that, After the protrusion extrudes the second machining portion to obtain the turbine rear axle forging, the method further includes: A test ring is machined on the end face of the turbine rear axle forging that corresponds to the second die cavity and is away from the upper die; The turbine rear axle forging was subjected to solution treatment; The test ring was subjected to solution treatment and aging treatment.

8. A turbine rear axle forging, manufactured according to the GH4169 alloy turbine rear axle forging manufacturing method according to any one of claims 1-7, characterized in that, include: The main body includes a first end face and a second end face that are disposed opposite to each other; The shaft portion is formed by extending the second end face portion of the body portion in a direction away from the first end face along the axial direction of the body portion. The recessed portion is formed by the first end face portion of the body portion being recessed along the axial direction of the body portion towards the second end face; A test ring is formed on the second end face of the main body.

9. The turbine rear axle forging according to claim 8, characterized in that, The shaft portion has a cylindrical structure, and the axes of the shaft portion, the body portion, the recessed portion, and the test ring coincide. The position where the body part connects to the shaft part is provided with a rounded corner; The recessed portion has a circular cross-section along the direction parallel to the first end face, and an inverted trapezoidal cross-section along the direction perpendicular to the first end face.

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