A method of forging a large size engine drum

Abstract

A large-size engine drum forging method, comprising the following steps: providing a TC4 welded bar with a diameter d, the bar height-diameter ratio is not less than 5; the bar is upset to a cake blank with a diameter not less than 2.4d by three times; three-pass die forging numerical simulation is carried out, and the final control parameters are obtained by correcting the die forging control parameters obtained by simulation by using the steel blank; the cake blank is die forged according to the final control parameters, and homogenization and annealing heat treatment are carried out. Through the above method, the high-efficiency forging of large-size engine supercharging stage drum with a diameter of 1000mm or more can be realized, the obtained part has uniform organization and no internal defects, and the room temperature and high temperature mechanical properties are stable.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of forging, and particularly relates to a large-size engine drum forging method. BACKGROUND

[0002] With the increase of the bypass ratio of commercial engines and the improvement of engine performance, the configuration of parts is continuously increased, and the structure is gradually complicated, which puts forward higher requirements on the performance and manufacturing process of large structural parts such as compressor drums. The engine supercharging stage drum is a key transmission component in the engine rotor, and the Ti-6Al-4V (TC4) titanium alloy is usually selected for the wide-body aircraft engine supercharging stage drum, and the size of the part can reach Φ1270mmx750mm. The maximum hardenability of TC4 titanium alloy is only 75mm, which leads to the fact that the structure cross-sectional size of the forged piece treated by solid solution and aging strengthening is strictly limited, further restricting the selection of the processing technology. The technical problems such as large deformation difference between the bottom and the edge, poor process repeatability, and difficult control of microstructure and performance and heat treatment hardenability in the large drum forging process are always difficult to overcome. According to the structure design of the new type of aero-engine, the blank weight of the supercharging stage drum is close to 3 tons, and the size of the forged piece has exceeded the processing capacity of the existing process. Therefore, it has high practical value for the manufacture of aero-engines to provide a large-size engine drum forging method. SUMMARY

[0003] The purpose of the present application is to provide a large-size engine drum forging method for forging large-size engine drums with a diameter of not less than 1000mm.

[0004] According to an embodiment of the present application, a large-size engine drum forging method is provided, which comprises the following steps: providing a TC4 alloy bar with a diameter d, the height-diameter ratio of the bar being not less than 5; performing three-fire upsetting on the bar to process a cake blank with a diameter of not less than 2.4d; providing control parameters for three-fire die forging of the cake blank and providing a steel blank, performing die forging test checking on the control parameters using the steel blank and correcting the control parameters to obtain final control parameters; performing three-fire die forging on the cake blank according to the final control parameters to obtain a drum blank; and performing homogenization and annealing heat treatment on the drum blank.

[0005] By this method, the problems of blanking and processing difficulty of large-size engine drums can be effectively solved, and stable and efficient forging processing of large-size engine drums can be effectively realized.

[0006] Further, in some embodiments, the heating temperature for upsetting and die forging is T β -50℃±10℃, wherein T β is the phase transition point temperature of TC4 alloy.

[0007] Furthermore, in some embodiments, in the three-stage upsetting process, the final forging temperature of each pass is ≤750℃, the deformation amount of the first pass is not less than 30%, the pressing speed is 5mm / s, and the end diameter of the bar after upsetting is 1.2d; the deformation amount of the second pass is not less than 40%, the pressing speed is 5mm / s, and the end diameter of the bar after upsetting is 1.6d; the deformation amount of the third pass is not less than 60%, the pressing speed is 3mm / s, and the blank is obtained after upsetting and rounding.

[0008] Furthermore, in some embodiments, in the three-pass forging process, the final forging temperature of each pass is ≤750℃, the deformation of the first pass is not less than 30%, and the under-pressure is 225±3mm; the deformation of the second pass is not less than 40%, and the under-pressure is 145±3mm; the deformation of the third pass is not less than 60%, and the under-pressure is 8±3mm.

[0009] Furthermore, in some embodiments, in the three-pass forging process, the equivalent strain of each pass does not exceed 0.9, and the cumulative equivalent strain is between 0.75 and 3.75.

[0010] Furthermore, in some embodiments, the heating temperature in the homogenization step is ((T) β -45℃~(T β -35℃ ±10℃, heat preservation time 210±5min, water cooling, wherein T β is the phase transformation temperature of TC4 alloy.

[0011] Furthermore, in some embodiments, the annealing step involves heating at 700±6℃, holding for 240±5min, and air cooling.

[0012] Furthermore, in some embodiments, after heat treatment, the drum blank has a room temperature tensile strength of not less than 1000 MPa, a yield strength of not less than 920 MPa, an elongation of not less than 12%, and a reduction of area of ​​not less than 25%.

[0013] Furthermore, in some embodiments, after heat treatment, the drum blank has a tensile strength of not less than 700 MPa, a yield strength of not less than 550 MPa, an elongation of not less than 15%, and a reduction of area of ​​not less than 50% at 300°C.

[0014] Furthermore, in some embodiments, the ultrasonic water immersion testing of the drum blank satisfies Φ0.8mm-(11-20)dB. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the engine drum structure in one embodiment;

[0016] Figures 2a-2c Fig. 4 is a schematic diagram of a bar upsetting process in an embodiment;

[0017] Figures 3a-3c Fig. 5 is a schematic diagram of a numerical simulation of a pancake forging in an embodiment;

[0018] Figures 4a-4c Fig. 6 is a schematic diagram of a pancake forging process in an embodiment;

[0019] Figure 5 Fig. 7 is a photograph of a drum local microstructure sample in an embodiment.

[0020] The above-described drawings are intended to provide a detailed description of the present application in order to enable a person skilled in the art to understand the technical concept of the present application, and are not intended to limit the present application. For the sake of brevity, the above-described drawings only schematically draw structures related to technical features of the present application, and do not draw complete structures and all details in strict accordance with actual proportions. DETAILED DESCRIPTION

[0021] The present application will be further described in detail by specific embodiments in conjunction with the drawings.

[0022] Reference to "an embodiment" herein means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment. The appearances of the phrase "in an embodiment" in various places in the specification do not necessarily refer to the same embodiment, nor do they necessarily refer to mutually exclusive or alternative embodiments. Those skilled in the art will appreciate that embodiments in this document can be combined with other embodiments in this document without structural conflicts.

[0023] In the description herein, terms indicating orientation or positional relationship such as "upper", "lower", "left", "right", "transverse", "longitudinal", "height", "length", "width", etc. are intended to accurately describe embodiments and simplify the description, and are not intended to limit the parts or structures involved to have a particular orientation, be installed or operated in a particular orientation, and should not be understood as limiting the embodiments herein.

[0024] In the description herein, terms such as "first", "second", etc. are only used to distinguish different objects, and should not be understood as indicating relative importance or limiting the number, specific order, or primary and secondary relationship of the technical features described. In the description herein, "a plurality of" means at least two.

[0025] The large passenger aircraft engine is a typical high-bypass-ratio turbofan engine, which is developed to meet the power demand of civil large aircraft. Compared with the large transport aircraft engine, the large passenger aircraft engine has higher requirements on life, reliability and economy. With the increase of the bypass ratio of commercial engines, the engine performance is improved, and the requirements on reliability and economy are increased. With the increase of the size and the gradual complexity of the structure of the parts, the performance requirements on the compressor drum parts are higher. Therefore, the performance requirements on the forgings are also increased. The pressurization stage drum of the engine is a key rotating part of the engine rotor, which has large size, complex structure, high mechanical performance requirements and high manufacturing difficulty. The pressurization stage drum of the wide-body passenger aircraft engine is made of Ti-6Al-4V (TC4) titanium alloy, and the size of the part is Φ1270mm×750mm. The maximum hardenability of TC4 titanium alloy is only 75mm, and the forgings treated by solid solution and aging strengthening should consider the limitation of the structural cross-sectional size. At present, there are the following problems in the large-size engine forging: 1. The drum has large size and barrel-shaped structure, and the deformation difference between the bottom and the edge is large. 2. The process repeatability is poor, and the current forging process adopts multi-fire forging, the forging process is uncontrollable, and the forging fire times and deformation amount are difficult to realize batch stable control. 3. There is still no experience in using bar tooling to assist in the blanking and die forging process, and large-size bars are still used for whole forging. Since the size of the pressurization stage drum of the wide-body passenger aircraft engine is larger, the bar diameter reaches Φ500mm, and it is difficult to control the microstructure and performance of the forgings and the hardenability of the heat treatment. For the pressurization stage drum, the blanking weight is close to 3 tons, and the size of the forging has exceeded the current process capacity in China.

[0026] To solve the above problems, one embodiment of the present application provides a large-size engine drum forging method. The engine drum structure manufactured by using the method is shown in Figure 1 The diameter D of the drum is 1252.4mm, and the thickness H is 770mm. The manufacturing process includes the following steps:

[0027] Blanking: Ti-6Al-4V (TC4) alloy is used as the raw material, which includes 6.46% of Al, 4.2% of V, 0.21% of Fe, 0.01% of C and 0.2% of O according to the mass ratio, and the content of H is 22ppm. The TC4 alloy raw material is a bar with a diameter d of 500mm.

[0028] Blanking: Since the diameter of the finished drum is large, it is difficult to obtain a titanium alloy bar with a larger diameter, so a bar with a height h of 2540mm is cut off, and the bar with a height-to-diameter ratio of 5.08 is used as the raw material for blanking. If the height-to-diameter ratio of the bar is greater than 5, it is difficult to be formed at one time by using the general processing method, otherwise the saddle-shaped deformation is easy to occur, so the blanking adopts three-fire upsetting processing, and the process is shown in Figures 2a-2c The bar is heated to T βAt a temperature of -50℃±10℃, with a pressing speed of 5mm / s controlling the deformation at 30%, the final forging temperature should not exceed 750℃. Figure 2a As shown, the bar stock is upset to an end diameter d1 = 600 mm and a height h1 = 1800 mm; during the second heat treatment, the bar stock is heated to T. β At a temperature of -50℃±10℃, with a pressing speed of 5mm / s controlling the deformation to 40%, the final forging temperature should not exceed 750℃. Figure 2b As shown, the bar stock is upset to an end diameter d2 = 800 mm and a height h2 = 1100 mm; during the three-stage processing, the bar stock is heated to T. β At a temperature of -50℃±10℃, with a downward pressing speed of 3mm / s controlling the deformation at 60%, and a final forging temperature not exceeding 750℃, the bar stock is upset, rounded, and the end face is upset to obtain a blank with a diameter d3=1240mm and a height h3=410mm. The transfer time during the upset process is less than 120s, and it is air-cooled after processing. During the upset process, a position-limited control method is adopted, stopping immediately upon the appearance of damage, followed by milling and grinding, with alternating upset and straightening operations. This results in a blank with a uniform internal structure, preventing instability.

[0029] Numerical simulation. Due to the high deformation resistance, poor fluidity, and difficulty in forming of titanium alloys, and the fact that the microstructure and properties of titanium alloy forgings are highly sensitive to forging thermodynamic parameters, numerical simulation is necessary to analyze and verify the forging process before die forging the billet, and to determine the control parameters for each processing pass. The numerical simulation process is as follows: Figures 3a-3c As shown, the deformation and flow state of the blank under different deformation amounts are simulated and calculated respectively. Based on factors such as die life, strain field distribution, actual equipment processing capacity and finished product ejection method, a comprehensive analysis is conducted to determine the control parameters in the three-stage die forging process, so as to improve the unevenness of the microstructure caused by the rapid cooling rate at the contact area between the forging and the die, and at the same time avoid overheating caused by deformation heat inside the forging.

[0030] Billet verification. After obtaining the forging control parameters through numerical simulation, the billet is used for die forging to verify and correct the control parameters, and the final control parameters are obtained iteratively.

[0031] Forging. (e.g.) Figures 4a to 4c As shown, the blank is forged using a three-stage die forging process. In the first stage, the blank 1 is heated to T. β The temperature is -50℃±10℃, the compression deformation is controlled at 30%, the under-compression is 225±3mm, and the final forging temperature does not exceed 750℃. Figure 4a As shown, blank 1 deforms and fills the top of mold cavity 2; during the second heat treatment, blank 1 is heated to T. β At a temperature of -50℃±10℃, control the compression deformation to 40%, the under-compression to 145±3mm, and the final forging temperature to not exceed 750℃.Figure 4b As shown, the blank 1 is deformed and filled to the middle of the die cavity 2; in the third working process, T β temperature of 50±10℃, controlled deformation of 60%, under pressure of 8±3mm, final forging temperature not exceeding 750℃, such as Figure 4c As shown, the blank 1 is deformed and filled to the middle of the die cavity 2; in the third working process, T

[0032] Homogenization treatment. The blank is heated to (T β -45℃)~(T β -35℃))±10℃, and kept for 210±5min to homogenize the structure.

[0033] Annealing treatment. The blank after homogenization treatment is heated to 700±6℃, kept for 240±5min, and cooled by air.

[0034] The open end of the drum blank manufactured in four different batches is cut into 20×20mm ring-shaped samples for room temperature and high temperature performance testing, and the results are shown in Table 1. The tensile strength of each sample at room temperature is 1016MPa-1040MPa, the standard deviation is 11MPa; the yield strength is 926MPa-970MPa, the standard deviation is 18MPa; the elongation after fracture is 15.6%-17%, the standard deviation is 1%; the end face shrinkage is 25%-42%, the standard deviation is 8%; the tensile strength at 300℃ is 738.5MPa-759.5MPa, the standard deviation is 9MPa; the yield strength is 595MPa-612.5MPa, the standard deviation is 7MPa; the elongation after fracture is 17.5%-20,%, the standard deviation is 9%; the shrinkage of the fracture surface is 57.5%-62%, the standard deviation is 2%. The metallographic analysis of the sample structure is shown in the metallographic photos Figure 5 As shown, the volume fraction of the born α phase in the sample is about 20%. The mechanical properties of each sample are significantly better than the requirements, and the performance of different samples shows a high consistency, and the method provided by the surface embodiment has good process stability.

[0035]

[0036] Table 1 Drum blank sample performance

[0037] The water immersion partition flaw detection is carried out on the drum blank, ultrasonic flaw detection is carried out on 9 different detection surfaces, noise is measured at the level of Φ0.8-12dB to Φ0.8-17dB, no abnormal signal is generated in the detection process, the surface forging quality meets the flaw detection requirements of the titanium alloy supercharging stage drum forging of Φ0.8-(11-20)dB, and the organization uniformity is good and no internal defects are generated.

[0038] The above embodiments are intended to further illustrate the present application in conjunction with the drawings, so that those skilled in the art can understand the technical concept of the present application. Within the scope of the embodiments of the present application, the method steps involved are optimized or equivalently replaced, or the implementation manners in different embodiments are combined without structural and principle conflicts, all of which fall within the protection scope of the present application.

Claims

1. A method for forging a large-size engine drum, characterized in that, Includes the following steps: Provide TC4 alloy bars with a diameter of d, wherein the height-to-diameter ratio of the bars is not less than 5; The bar stock is subjected to three upsetting processes to produce a blank with a diameter of not less than 2.4d; Control parameters for the three-stage die forging of the billet are provided, and a steel billet is provided. The control parameters are verified and corrected using the steel billet through die forging tests to obtain the final control parameters. In the three-stage upsetting step, the final forging temperature of each pass is ≤750℃, the deformation of the first pass is not less than 30%, the pressing speed is 5mm / s, and the end diameter of the bar after upsetting is 1.2d; the deformation of the second pass is not less than 40%, the pressing speed is 5mm / s, and the end diameter of the bar after upsetting is 1.6d; the deformation of the third pass is not less than 60%, the pressing speed is 3mm / s, and the billet is obtained after upsetting and rounding. The final forging temperature of each pass is ≤750℃, the deformation of the first pass is not less than 30%, and the under-pressure is 225±3mm; the deformation of the second pass is not less than 40%, and the under-pressure is 145±3mm; the deformation of the third pass is not less than 60%, and the under-pressure is 8±3mm. The blank is forged in three stages according to the final control parameters to obtain a drum blank. The drum blank is subjected to homogenization and annealing heat treatment.

2. The method for forging a large-size engine drum according to claim 1, characterized in that, The heating temperature for upsetting and forging is T. β -50℃±10℃, where T β is the phase transformation temperature of TC4 alloy.

3. The method for forging a large-size engine drum according to claim 1 or 2, characterized in that, In the three-stage die forging process, the equivalent strain of each pass does not exceed 0.9, and the cumulative equivalent strain is between 0.75 and 3.

75.

4. The method for forging a large-size engine drum according to claim 1 or 2, characterized in that, In the homogenization step, the heating temperature is ((T) β -45℃)~( T β -35℃±10℃, heat preservation time 210±5min, water cooling, where T β is the phase transformation temperature of TC4 alloy.

5. The method for forging a large-size engine drum according to claim 1 or 2, characterized in that, In the annealing step, the heating temperature is 700±6℃, the holding time is 240±5min, and the cooling is done by air cooling.

6. The method for forging a large-size engine drum according to claim 1 or 2, characterized in that, After heat treatment, the drum blank has a room temperature tensile strength of not less than 1000 MPa, a yield strength of not less than 920 MPa, an elongation of not less than 12%, and a reduction of area of ​​not less than 25%.

7. The method for forging a large-size engine drum according to claim 1 or 2, characterized in that, After heat treatment, the drum blank shall have a tensile strength of not less than 700 MPa, a yield strength of not less than 550 MPa, an elongation of not less than 15%, and a reduction of area of ​​not less than 50% at 300°C.

8. The method for forging a large-size engine drum according to claim 1 or 2, characterized in that, The ultrasonic water immersion test of the drum blank meets the requirements of Φ0.8mm-(11-20)dB.

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