Aircraft engine fuel pump housing forging forming method

Abstract

The present application relates to the technical field of aero-engine parts manufacturing, in particular to a forging forming method for an aero-engine fuel pump shell; comprising the following steps: S1, rough machining, S2, primary forging, S3, secondary forging, S4, secondary processing, S5, tertiary forging, S6, tertiary processing; the present application can effectively remove cracks and folding defects in the forging process through tertiary forging and post-forging processing, and can also effectively optimize defects such as corrosion points, black spots, abnormal mottling, peeling, bubbles, dents and indentations.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of aircraft engine parts manufacturing, in particular to a forging forming method for an aircraft engine fuel pump shell. BACKGROUND

[0002] The aircraft engine fuel pump is an indispensable component in the engine, and its main function is to supply fuel to the engine system to ensure its smooth operation. The pressure and flow control of the fuel pump are very important, which can directly affect the working quality and efficiency of the engine. The fuel pump shell, as the outer protection of the fuel pump, can ensure that internal components such as motors, pressure limiters, and check valves are not disturbed by the outside world during operation, and maintain a stable operating environment. If the shell has defects, such as insufficient material density or problems during the manufacturing process, it may cause the fuel pump to work poorly, and even cause safety hazards. At the same time, if the shell is deformed due to material or manufacturing problems, it may interfere with the internal components, causing the fuel pump to malfunction, and in extreme cases, it may cause the engine to stall during flight, posing a threat to the safety of the aircraft.

[0003] The most important alloy material in the forging process of the fuel pump shell is aluminum alloy, but aluminum alloy structural parts are prone to defects during forging, which can cause the fuel pump shell to deform. Common defects of aluminum alloy include: 1. A circle at the root of the upper die inner corner is prone to "folding", and local corner positions are prone to folding; 2. The lower die has obvious "folding", which exists 100% in one place and partially exists in another place.

[0004] In view of the folding and other defects of the structural part during the forging process, the present application designs a forging forming method for an aircraft engine fuel pump shell. SUMMARY

[0005] In order to solve the above problems, the present application provides a forging forming method for an aircraft engine fuel pump shell.

[0006] A forging forming method for an aircraft engine fuel pump shell, comprising the following steps:

[0007] S1, rough machining

[0008] First, the blank with a specification of Φ340±0.6×90±1mm is machined to a size of Φ330±0.4×88±1mm, and the surface roughness of the two ends of the blank is ≤Ra3.2, to obtain a rough machining blank.

[0009] S2, first forging

[0010] Heating the roughing billet to 470±10℃ and holding for 50~150min, then rolling, flattening the billet along the radial direction to a thickness of 8+2.0-1.0mm and a width of 66~70mm, hot charging, and holding at a finish forging temperature of ≥380℃ for 25~75min, air cooling after forging, to obtain a primary forged piece, then cleaning treatment;

[0011] S3, secondary forging

[0012] Continuing to heat the cleaned primary forged piece to 470±10℃ and holding for 16~80min, then placing the billet transversely into the die cavity for die forging, first hitting a hammer with a striking energy of 15±5% of the total striking energy of the equipment, then taking out the billet and cleaning the dirt in the die cavity, placing the billet into the die cavity for die forging again with a striking energy of 30±5% of the total striking energy of the equipment, underpressure: 0.5~1.0, hot charging, and holding at a finish forging temperature of ≥380℃ for 8~40min, air cooling after forging, to obtain a secondary forged piece;

[0013] S4, secondary processing

[0014] Placing the secondary forged piece in the trimming negative die to trim the residual burr of the secondary forged piece to ≤1.0mm, the wall thickness difference to ≤0.8, and the misalignment to ≤0.4mm, cleaning treatment and polishing to be defect-free, polishing the residual burr of the trimming, the residual burr to ≤1.0mm, and again cleaning treatment;

[0015] S5, tertiary forging

[0016] Continuing to heat the cleaned secondary forged piece to 470±10℃ and holding for 10~80min, placing the secondary forged piece into the die cavity according to the shape for die forging with a striking energy of 10±5% of the total striking energy of the equipment, hot charging, and holding at a finish forging temperature of ≥380℃ for 5~40min, air cooling after forging, to obtain a tertiary forged piece;

[0017] S6, tertiary processing

[0018] Placing the tertiary forged piece in the trimming negative die to trim the residual burr of the tertiary forged piece to ≤1.0mm, the wall thickness difference to ≤0.8, and the misalignment to ≤0.4mm, cleaning treatment and polishing to be defect-free, polishing the residual burr of the trimming, the residual burr to ≤1.0mm, and again cleaning treatment, then solid solution, correction, and aging treatment, and secondary polishing, and inspection.

[0019] Further, before step S1, rounding the two ends of the billet to R3;

[0020] Note: After the billet is sawn and cut, there will be a sawtooth step on the end face, and there will also be a circle of sharp edges. Rounding the two ends of the billet can effectively avoid defects caused by forging the sawtooth step / sharp edges to the surface of the product in subsequent forging production.

[0021] Further, the billet transfer time in step S2, step S4 and step S5 is ≤10s;

[0022] Description: After the billet is discharged, the temperature will be lost due to contact with the outside air, and the billet transfer time is required to be ≤10s, which can more effectively ensure the final forging temperature of the product, thereby ensuring the performance of the forgings.

[0023] Further, the cleaning treatment is to remove the grease and dirt on the surface of the forgings, and the removal amount is not greater than 0.02mm;

[0024] Description: The corrosion process is mainly to clean the grease and dirt on the surface of the forgings, and by controlling the surface removal amount, the excessive corrosion of the forgings can be effectively prevented to avoid defects.

[0025] Further, in step S2, the billet is placed close to the damping table;

[0026] Description: A "damping table" is added at the sharp corner position of the pre-forging die to ensure that the metal at position C is quickly filled, and since the material demand at the sharp corner position is high, the material filling at this position is slow during the pre-forging process. In fact, the material filling on both sides of the sharp corner is faster, and then converges to the sharp corner position, thereby forming a fold at the sharp corner position. By adding the "damping table", the material filling at the sharp corner position can be effectively accelerated, and the generation of fold defects can be prevented.

[0027] Further, in step S6, the temperature of the solid solution treatment is 1080-1120℃, the heating rate is 3-5℃ / min, and the holding time is 1-3h;

[0028] Description: The solid solution treatment can effectively improve the plasticity and toughness of the fuel pump shell forgings, fully dissolve various phases of the alloy, strengthen the solid solution, improve the toughness and corrosion resistance, eliminate stress and softening, and facilitate subsequent processing or forming.

[0029] Further, in step S3, the correction method is to place a flat steel plate on the flat position of the die holder, adjust the upper and lower gap: H=8.5±0.2mm; After removing the impurities and oil stains on the surface of the upper and lower flat plates, the forgings are placed on the die holder for correction, and the striking energy is 3-5% of the total striking energy of the equipment;

[0030] Description: Since the product structure is a thin plate type, it will be slightly warped after production and affect subsequent processing, so the deformation of the forgings is eliminated by correction to ensure subsequent product processing.

[0031] Further, in step S3, the method of the aging treatment is to perform intermittent vibration aging and pulse current collaborative treatment in three stages,

[0032] The first stage: the cold-pressed three times forgings are treated at 100-110 DEG C for 5-7 hours, then pulse current is applied at a frequency of 20000-25000 Hz, a voltage of 30-50 V, and a current density of 60-100 A / mm, and the application time is 30-50 min, wherein the frequency spectrum harmonic vibration aging treatment is performed for 30-70% of the current density application time;

[0033] The second stage: the frequency of the pulse current is adjusted to 15000-20000 Hz, the voltage and the current density remain unchanged, and the application time continues to be performed for 40-60% of the current density application time;

[0034] The third stage: the pulse voltage is adjusted to 10-30 V, the current density is 5-40 A / mm, the application frequency and the application time remain unchanged, and the frequency spectrum harmonic vibration aging treatment is continued to be performed for 20-80% of the current density application time.

[0035] Description: The vibration aging treatment can change the dislocation configuration of the internal crystals of the forgings, form the jamming and entanglement of dislocations, and increase the dislocation density, which helps to delay the initiation and expansion of fatigue cracks. Compared with the traditional thermal aging treatment, the vibration aging treatment has the advantages of low energy consumption and small environmental pollution. The vibration aging treatment and the pulse current treatment can improve the strength and ductility of the material. Specifically, the pulse current treatment can promote the movement of solute atoms during solid solution, increase the supersaturation of the sample, and thus promote the coarsening and distribution of the strengthening phase during the aging treatment, improve the microstructure of the material, and accelerate the microstructure evolution of the deformation aging alloy, thereby improving the strength and ductility of the alloy.

[0036] Further, the parameters of the frequency spectrum harmonic vibration aging treatment are as follows: the frequency is 200-1000 Hz, the vibration time is 5-15 min, the vibration times are 3-10 times, and after each frequency spectrum harmonic vibration aging treatment, the treatment liquid is sprayed on the surface of the three times forgings at a spraying amount of 2-4 mL / cm 2 , and then the same extrusion force is applied to the three times forgings in the transverse / longitudinal / axial direction in sequence. The extrusion force of the first stage is 100-150 MPa, the extrusion force of the second stage is 120-150% of the first stage, and the extrusion force of the third stage is 30-50% of the second stage.

[0037] The treatment liquid comprises, by mass percentage, 25-35% of agar, 3-7% of a water-based graphite lubricant, 6-10% of chitin, and the balance of an aqueous solution containing 8-12 wt% of a hydrocarbon-based phosphoric acid;

[0038] Note: intermittent vibration and aging treatment can eliminate internal stress uniformly in advance and reduce the possibility of defect generation; the combination of the two treatment methods, especially in the case of folding and other defects during forging, can provide multiple advantages; hydrocarbyl phosphoric acid has lubricating properties and surface activity, which can reduce the surface tension of the alloy, thereby reducing the formation of cracks after welding; when the water-based graphite lubricant is sprayed in a high-temperature environment, the rapid evaporation of water can carry away part of the heat, which plays a certain cooling role, which helps to maintain the temperature balance during the aging treatment process and prevent abnormal metal flow and folding defects caused by excessive temperature; at the same time, in the low-temperature phosphoric acid aqueous solution, chitin can form a high-strength film, and the addition of chitin can also enhance the overall structure of the material by forming hydrogen bonds and physical cross-linking networks, thereby reducing stress concentration and improving the toughness of the material; the addition of agar can enhance the overall structure of the material by forming a physical cross-linking network, thereby reducing stress concentration.

[0039] Compared with the prior art, the beneficial effects of the present application are:

[0040] (1) The present application can effectively remove cracks and folding defects in the forging process through three times of forging and post-forging treatment. For upper die folding: by designing pre-forging, the local original angle of the forged part is increased to improve the flow of the raw material; for lower die folding: by designing pre-forging, the outer contour cavity surface is appropriately reduced, so that it can be smoothly put into the final forging cavity during the final forging process, preventing the formation of folding due to wall scratching, and the defects of corrosion points, black spots, abnormal mottling, peeling, bubbles, scratches, and pressed-in objects can also be effectively optimized.

[0041] (2) The present application uses vibration and aging treatment to change the dislocation configuration of the internal crystals of the forged part, forming a pile-up and entanglement of dislocations, and increasing the dislocation density, thereby delaying the initiation and propagation of fatigue cracks in the forged part. In addition, the present application uses vibration and aging treatment in combination with pulse current treatment, which can promote the movement of solute atoms during solid solution, increase the supersaturation of the sample, promote the coarsening and distribution of strengthening phases during aging treatment, improve the microstructure of the material, and improve the strength and ductility of the material. BRIEF DESCRIPTION OF DRAWINGS

[0042] Figure 1 is a schematic diagram of defects in the forging of an aero-engine fuel pump shell;

[0043] Figure 2 is a pre-forging and final forging cross-sectional view of the blank group of the present application;

[0044] Figure 3 is a pre-forging and final forging cross-sectional view of Example 1 of the present application;

[0045] Figure 4is a blank layout of Example 1 of the present application;

[0046] Figure 5 is a preform-contact analysis and a preform-fold analysis diagram of Example 1 of the present application;

[0047] Figure 6 is a finish forging-contact analysis and a finish forging-fold analysis diagram of Example 1 of the present application;

[0048] Figure 7 is an upper die plan view of a finish forging piece of the present application;

[0049] Figure 8 is an upper die plan view of a preform piece of the present application;

[0050] Figure 9 is an upper die three view of a preform piece of the present application;

[0051] Figure 10 is an upper die three view of a preform piece of the present application;

[0052] Figure 11 is a lower die plan view of a preform piece of the present application;

[0053] Figure 12 is a fold defect rate comparison diagram of Example 1 to Example 3 and Control Group 1 to Control Group 2 of the present application;

[0054] Figure 13 is a tensile strength comparison diagram of Example 1 to Example 3 and Control Group 1 to Control Group 2 of the present application;

[0055] Figure 14 is an elongation rate comparison diagram of Example 1 to Example 3 and Control Group 1 to Control Group 2 of the present application;

[0056] Figure 15 is a fold defect rate comparison diagram of Example 1, Example 4 to Example 11 and Control Group 3 to Control Group 4 of the present application;

[0057] Figure 16 is a tensile strength comparison diagram of Example 1, Example 4 to Example 11 and Control Group 3 to Control Group 4 of the present application;

[0058] Figure 17 is an elongation rate comparison diagram of Example 1, Example 4 to Example 11 and Control Group 3 to Control Group 4 of the present application;

[0059] Figure 18 is a fold defect rate comparison diagram of Example 1, Example 12 to Example 18 and Control Group 5 to Control Group 6 of the present application;

[0060] Figure 19is a tensile strength comparison chart of example 1, example 12 to example 18 and control group 5 to control group 6 of the present application;

[0061] Figure 20 is an elongation comparison chart of example 1, example 12 to example 18 and control group 5 to control group 6 of the present application;

[0062] In the figure: position ①: pre-forging is offset by 0.2mm relative to finish forging;

[0063] Position ②: pre-forging is offset by 1.0mm relative to finish forging;

[0064] Position ③: finish forging R=1.2, pre-forging design R=2.0;

[0065] Position ④: finish forging R=2.5, pre-forging design R=3.5;

[0066] Position ⑤: finish forging R=1.2, pre-forging design R=1.8;

[0067] Position ⑥: finish forging draft=7°, pre-forging draft=9°. DETAILED DESCRIPTION

[0068] In order to further illustrate the manner of carrying out the present application and to further demonstrate the effects achieved by it, the technical solutions of the present application will be clearly and completely described below in conjunction with experiments.

[0069] Example 1: a method for forging and shaping an aero-engine fuel pump shell, comprising the following steps:

[0070] S1, rough machining

[0071] First, a blank with a specification of Φ340*90mm is processed to a size of Φ330*88mm, the surface finish of the two end faces of the blank is not less than Ra3.2, and then the two end faces of the blank are rounded to R3 to obtain a rough machining blank;

[0072] S2, primary forging

[0073] The rough machining blank is heated to 470℃ and kept for 100min, then rolled to flatten the blank in the radial direction to a thickness of 9.0mm and a width of 68mm, the hot material is recycled, and kept at a finish forging temperature of 380℃ for 55min, air-cooled after forging, to obtain a primary forged piece, and then cleaned;

[0074] S3, secondary forging

[0075] continue heating the once-forged workpiece after cleaning to 470 DEG C, and keep for 40 min, then put the blank transversely into the die cavity for die forging, first hit a hammer, the striking energy is 15% of the total striking energy of the equipment, then take out the blank, clean the dirt in the die cavity, then put the blank into the die cavity for die forging, the striking energy is 30% of the total striking energy of the equipment, under-pressure: 0.8, hot material is recycled, and keep for 25 min at the final forging temperature of 380 DEG C, and air cool after forging, to obtain a twice-forged workpiece; it should be noted that in the present scheme, the striking equipment refers to a commercially available 315T electric screw press;

[0076] S4, secondary processing

[0077] Put the twice-forged workpiece into the trimming negative die to trim the residual burr of the twice-forged workpiece to 1.0 mm, the wall thickness difference is 0.8, and the misalignment is 0.4 mm; clean and polish to be defect-free, polish the residual burr of trimming, the residual burr is 1.0 mm, and clean again;

[0078] S5, three times forging

[0079] Continue heating the twice-forged workpiece after cleaning to 470 DEG C, and keep for 50 min, put the twice-forged workpiece into the die cavity according to the type for die forging, the striking energy is 10% of the total striking energy of the equipment, hot material is recycled, and keep for 25 min at the final forging temperature of 380 DEG C, and air cool after forging, to obtain a three times-forged workpiece;

[0080] S6, three times processing

[0081] Put the three times-forged workpiece into the trimming negative die to trim the residual burr of the three times-forged workpiece to 1.0 mm, the wall thickness difference is 0.8, and the misalignment is 0.4 mm; clean and polish to be defect-free, polish the residual burr of trimming, the residual burr is 1.0 mm, and clean again, then polish twice after solid solution, correction and aging treatment, and send for inspection;

[0082] During the polishing process, the cracks, folds and corrosion spots on the machined surface of the workpiece must be completely removed, the peeling, bubbles, dents, indentations and other defects are allowed to be cleaned and determined for their depth, but the workpiece must be ensured to have not less than one-half of the nominal machining allowance; the cracks, folds and other defects affecting use on the non-machined surface of the workpiece shall be removed, and the position of the removed defects shall ensure the minimum limit size of the single surface of the workpiece;

[0083] Before step S1, round the two ends of the blank to R3;

[0084] In steps S2, S4 and S5, the blank transfer time is 10 s;

[0085] The cleaning treatment is to remove the grease and dirt on the surface of the workpiece, and the removal amount is 0.02 mm;

[0086] In step S2, the blank is placed close to the damping platform; the distance is as shown in Figure 4 ;

[0087] In step S3, the temperature of the solid solution treatment is 1100℃, the heating rate is 4℃ / min, and the holding time is 2h.

[0088] In step S3, the correction method is as follows: the flat steel plate is laid on the flat position of the die holder, and the upper and lower clearances are adjusted: H=8.5mm; before correction, the impurities and oil stains on the surface of the upper and lower flat plates are removed clean, and then the forging is placed on the die holder for correction, and the striking energy is 4% of the total striking energy of the equipment.

[0089] Example 2: Different from example 1, in step S2, the rough machining blank is heated to 460℃ and held for 50min, and then rolled, and the blank is flattened along the radial direction to a thickness of 7.0mm and a width of 66mm, the hot material is recycled, and held for 25min at a final forging temperature of 400℃, and then air-cooled after forging to obtain a primary forging, and then cleaned.

[0090] Example 3: Different from example 1, in step S2, the rough machining blank is heated to 480℃ and held for 150min, and then rolled, and the blank is flattened along the radial direction to a thickness of 9.0mm and a width of 70mm, the hot material is recycled, and held for 75min at a final forging temperature of 385℃, and then air-cooled after forging to obtain a primary forging, and then cleaned.

[0091] Example 4: Different from example 1, in step S3, the cleaned primary forging is further heated to 460℃ and held for 16min, and then the blank is placed horizontally into the die cavity for die forging, first hit a hammer, the striking energy is 10% of the total striking energy of the equipment, then take out the blank, clean the dirt in the die cavity, and then put the blank into the die cavity for die forging, the striking energy is 25% of the total striking energy of the equipment, the underpressure is 0.5, the hot material is recycled, and held for 8min at a final forging temperature of 380℃, and then air-cooled after forging to obtain a secondary forging.

[0092] Example 5: Different from example 1, in step S3, the cleaned primary forging is further heated to 480℃ and held for 80min, and then the blank is placed horizontally into the die cavity for die forging, first hit a hammer, the striking energy is 20% of the total striking energy of the equipment, then take out the blank, clean the dirt in the die cavity, and then put the blank into the die cavity for die forging, the striking energy is 35% of the total striking energy of the equipment, the underpressure is 1.0, the hot material is recycled, and held for 40min at a final forging temperature of 380℃, and then air-cooled after forging to obtain a secondary forging.

[0093] Example 6: Different from example 1, in step S3, the temperature of solution treatment is 1080℃, the heating rate is 3℃ / min, and the holding time is 1h.

[0094] Example 7: Different from example 1, in step S3, the temperature of solution treatment is 1120℃, the heating rate is 5℃ / min, and the holding time is 3h.

[0095] Example 8: Different from example 1, in step S3, the correction method is as follows: the flat steel plate is laid on the flat position of the die holder, the upper and lower gap is adjusted to H=8.3mm; the impurities and oil stains on the surface of the upper and lower flat plate positions are cleaned before correction, then the forged piece is placed on the die holder for correction, and the striking energy is 3% of the total striking energy of the equipment.

[0096] Example 9: Different from example 1, in step S3, the correction method is as follows: the flat steel plate is laid on the flat position of the die holder, the upper and lower gap is adjusted to H=8.7mm; the impurities and oil stains on the surface of the upper and lower flat plate positions are cleaned before correction, then the forged piece is placed on the die holder for correction, and the striking energy is 5% of the total striking energy of the equipment.

[0097] Example 10: Different from example 1, in step S5, the cleaned secondary forged piece is continuously heated to 460℃ and held for 10min, then the secondary forged piece is placed into the die cavity according to the type for die forging, the striking energy is 5% of the total striking energy of the equipment, the hot material is recycled, and the final forging temperature is 380℃, the holding time is 5min, the forged piece is air cooled after forging, and the tertiary forged piece is obtained.

[0098] Example 11: Different from example 1, in step S5, the cleaned secondary forged piece is continuously heated to 480℃ and held for 80min, then the secondary forged piece is placed into the die cavity according to the type for die forging, the striking energy is 15% of the total striking energy of the equipment, the hot material is recycled, and the final forging temperature is 380℃, the holding time is 40min, the forged piece is air cooled after forging, and the tertiary forged piece is obtained.

[0099] Example 12: Different from example 1, in step S3, the aging treatment method is as follows: the intermittent vibration aging and pulse current synergistic treatment are divided into three stages,

[0100] First stage: the tertiary forged piece after cold pressing is held at 105℃ for 6h, then the pulse current is applied at a frequency of 22500Hz, a voltage of 40V, and a current density of 80A / mm, the application time is 30~50min, and the frequency spectrum harmonic vibration aging treatment is applied within 30~70% of the current density application time;

[0101] The second stage: adjust the frequency of the pulse current to 18000 Hz, the voltage and the current density and the application time remain unchanged, continue to perform the frequency spectrum harmonic vibration aging treatment within 40-60% of the current density application time;

[0102] The third stage: adjust the pulse voltage to 20 V, the current density to 25 A / mm, the application frequency and the application time remain unchanged, continue to perform the frequency spectrum harmonic vibration aging treatment within 20-80% of the current density application time;

[0103] The parameters of the frequency spectrum harmonic vibration aging treatment are: the frequency is 600 Hz, the vibration time is 10 min, the vibration times are 6, after each frequency spectrum harmonic vibration aging treatment, the treatment liquid is sprayed on the surface of the three times forgings according to the spraying amount of 3 mL / cm 2 , and then the same extrusion force is applied to the three times forgings in the transverse / longitudinal / axial direction in turn. The extrusion force of the first stage is 125 MPa, the extrusion force of the second stage is 130% of the first stage, and the extrusion force of the third stage is 40% of the second stage.

[0104] The treatment liquid comprises, by mass percentage, 30% of agar, 5% of a water-based graphite lubricant, 8% of chitin, and the balance of a water solution containing 10 wt% of a hydrocarbon-based phosphoric acid.

[0105] Example 13: Different from example 12, in step S3, the aging treatment method is: intermittent vibration aging and pulse current collaborative treatment are performed in three stages,

[0106] The first stage: the cold-pressed three times forgings are treated at 100℃ for 5 h, then the pulse current is applied at a frequency of 20000 Hz, a voltage of 30 V, and a current density of 60 A / mm, and the application time is 30-50 min, wherein the frequency spectrum harmonic vibration aging treatment is performed within 30-70% of the current density application time.

[0107] The second stage: adjust the frequency of the pulse current to 15000 Hz, the voltage and the current density and the application time remain unchanged, continue to perform the frequency spectrum harmonic vibration aging treatment within 40-60% of the current density application time;

[0108] The third stage: adjust the pulse voltage to 10 V, the current density to 5 A / mm, the application frequency and the application time remain unchanged, continue to perform the frequency spectrum harmonic vibration aging treatment within 20-80% of the current density application time.

[0109] Example 14: Different from example 12, in step S3, the aging treatment method is: intermittent vibration aging and pulse current collaborative treatment are performed in three stages,

[0110] The first stage: the cold-pressed three times forgings are treated at 110℃ for 7h, then pulse current is applied at a frequency of 25000Hz, a voltage of 50V, and a current density of 100A / mm, and the application time is 50min, wherein the frequency spectrum harmonic vibration aging treatment is carried out in 30-70% of the current density application time;

[0111] The second stage: the frequency of the pulse current is adjusted to 20000Hz, the voltage and the current density and the application time remain unchanged, and the frequency spectrum harmonic vibration aging treatment is continued to be carried out in 40-60% of the current density application time;

[0112] The third stage: the pulse voltage is adjusted to 30V, the current density is 40A / mm, the application frequency and the application time remain unchanged, and the frequency spectrum harmonic vibration aging treatment is continued to be carried out in 20-80% of the current density application time.

[0113] Example 15: Different from example 12, the parameters of the frequency spectrum harmonic vibration aging treatment are: the frequency is 200Hz, the vibration time is 5min, the vibration times are 3, and after each frequency spectrum harmonic vibration aging treatment, the treatment liquid is sprayed on the surface of the three times forgings according to a spraying amount of 2mL / cm 2 , and then the same extrusion force is applied to the three times forgings in the transverse direction / longitudinal direction / axial direction in turn, the extrusion force of the first stage is 100MPa, the extrusion force of the second stage is 120% of that of the first stage, and the extrusion force of the third stage is 30% of that of the second stage.

[0114] Example 16: Different from example 12, the parameters of the frequency spectrum harmonic vibration aging treatment are: the frequency is 1000Hz, the vibration time is 15min, the vibration times are 10, and after each frequency spectrum harmonic vibration aging treatment, the treatment liquid is sprayed on the surface of the three times forgings according to a spraying amount of 4mL / cm 2 , and then the same extrusion force is applied to the three times forgings in the transverse direction / longitudinal direction / axial direction in turn, the extrusion force of the first stage is 150MPa, the extrusion force of the second stage is 150% of that of the first stage, and the extrusion force of the third stage is 50% of that of the second stage.

[0115] Example 17: Different from example 12, the treatment liquid comprises, by mass percentage, 25% of agar, 3% of water-based graphite lubricant, 6% of chitin, and the balance of aqueous solution containing 8wt% of hydrocarbyl phosphoric acid.

[0116] Example 18: Different from example 12, the treatment liquid comprises, by mass percentage, 35% of agar, 7% of water-based graphite lubricant, 10% of chitin, and the balance of aqueous solution containing 12wt% of hydrocarbyl phosphoric acid.

[0117] Experimental Example: The description basis of this experimental example is the recorded scheme in Examples 1-18, which aims to illustrate the practical application effect of the present application. The appearance and mechanical properties of the aero-engine fuel pump housings obtained in Examples 1-18 are tested, and comparative examples are set.

[0118] The fuel pump housing forgings produced by the methods of Examples 1-18 are subjected to 100% visual inspection, and the fuel pump housing forgings of Examples 1-18 are all good in surface quality and free of cracks, folds and other defects; and the mechanical properties of the fuel pump housings of Examples 12-18 are better, and the quality is higher than that of Examples 1-11; Comparative Examples 1-5 have slight cracks and folds on the surface, and the surface quality is not as good as that of Examples 1-18; it is shown that the method of Examples 1-18 is improved compared with the comparative examples; the aero fuel pump housings obtained in Examples 1-18 are subjected to metallographic structure observation, and it is obtained that the grain size is 8 or less, and the distribution is uniform;

[0119] 1. Explore the influence of billet car end face / chamfer and flattening blanking / preforming shape design on the performance of engine fuel pump housing

[0120] Control group 1: Different from Example 1, the two end faces of the billet are not chamfered.

[0121] Control group 2: Different from Example 1, no processing is performed after flattening in the one-time forging process.

[0122] Conclusion: From the comparison of Examples 1-3 and Control Groups 1-2 in Figures 12 to 14 It can be seen from the comparison of Examples 1-3 and Control Groups 1-2 that in Examples 1-3, the billet car end face / chamfer can effectively avoid the formation of defects on the surface of the sawtooth step / sharp edge forged product; through the flattening blanking / preforming shape design, the shape of the final forging can be effectively matched, thereby avoiding the generation of product surface defects; the performance of the fuel pump housings obtained in Control Groups 1-2 is lower than that of Examples 1-3, and the defect rate is also significantly improved.

[0123] 2. Explore the influence of parameter changes in the forging process on the performance of the engine fuel pump housing

[0124] Control group 3: Different from Example 1, the billet placement position is not limited.

[0125] Control group 4: Different from Example 1, the flat surface impurities and oil stains are not additionally treated before correction.

[0126] Conclusion: Through the comparison of Examples 1-3 and Control Groups 3-4, it can be seen that in Control Groups 3-4, the billet placement position is not limited, and the flat surface impurities and oil stains are not additionally treated before correction, which can effectively avoid the formation of defects on the surface of the product, and the performance of the fuel pump housings obtained in Control Groups 3-4 is lower than that of Examples 1-3, and the defect rate is also significantly improved. Figures 15 to 17As shown, it can be found that the blank placement position limitation of the control group 3 also causes the performance of the fuel pump shell to decrease significantly, and the example 1 increases the "damping table" at the sharp corner position of the pre-forging die to ensure that the metal at the position C is filled quickly, and since the material demand at the sharp corner position of the forging is large, the material filling at the position is slow during the pre-forging process, and the material filling on both sides of the sharp corner is actually fast, and then converges to the sharp corner position, thereby forming a fold at the sharp corner position. The "damping table" can effectively accelerate the material filling at the sharp corner position and prevent the generation of fold defects; the lack of processing of the upper and lower plate position surfaces in the control group 4 makes the fold defect elimination rate of the obtained fuel pump shell weaken, and the heating temperature, holding time, surface cleaning, heat treatment and other parameters in the entire production process of the example 1, the example 4 to the example 11 are too large or too small, which can cause the product quality and the pass rate of the product physical and chemical items to decrease, and the defect rate of the engine fuel pump shell obtained under the parameters of the example 1 is the lowest, and the mechanical properties are the best.

[0127] Exploring the influence of aging treatment method on the performance of engine fuel pump shell

[0128] Control group 5: Different from the example 12, the time of the frequency spectrum harmonic vibration aging treatment is not adjusted with each stage.

[0129] Control group 6: Different from the example 12, no extrusion force is applied to the three forgings.

[0130] Control group 7: Different from the example 12, no water-based stone is added to the treatment liquid.

[0131] Conclusion: Through Figures 18 to 20It can be concluded that the performance of the engine fuel pump housings prepared in Examples 12-18 is significantly improved compared to the engine fuel pump housing prepared in Example 1, and the folding defects are smaller, and the performance effect of Example 12 is better; and from the comparison of Examples 12-14 and Control Group 5, it can be concluded that the frequency spectrum harmonic vibration aging treatment in the 30-70% time, 40-60% time and 20-80% time of the pulse current application in stages can help the metal flow at the folding part to be more uniform in the first stage, thereby reducing the depth and roughness of the surface folding, making the surface more flat, reducing the defect rate, in the second stage, with the optimization of the crystal structure and the further adjustment of the internal stress, the deformation coordination of the internal microstructure of the forged piece is better in the stretching process, the interatomic bonding can be more uniformly broken and reformed in the stretching process, so that the elongation rate of the forged piece is improved, and it has better deformation capacity before breaking; the longer treatment time in the third stage makes the dislocation movement and crystal structure adjustment in the forged piece more sufficient, and the combined effect of pulse current and vibration aging continuously affects the forged piece in this wide time range, so that the internal crystal structure is continuously optimized, forming a more dense and stable structure, thereby improving the tensile strength of the forged piece; in Control Group 6, not applying extrusion pressure to the forged piece will weaken the effect of the treatment liquid, thereby reducing the mechanical properties; in Control Group 7, the lack of water-based graphite lubrication will make the temperature unstable during the aging treatment process, thereby causing abnormal metal flow and folding defects due to excessive temperature; in summary, the scheme of Example 12 can further improve the performance and folding defects of the engine fuel pump housing, thereby improving the forging efficiency.

Claims

1. A method for forging a fuel pump housing for an aircraft engine, characterized in that, Includes the following steps: S1, Rough machining First, the blank with a specification of Φ340±0.6×90±1mm is machined to a size of Φ330±0.4×88±1mm. The surface roughness of both ends of the blank is ≤Ra3.2, thus obtaining a rough-machined blank. S2, One-time forging Heating the rough-machined billet to 470±10℃ and holding it for 50~150min, then rolling it to flatten it radially to a thickness of 8+2.0-1.0mm and a width of 66~70mm. The hot material is returned to the furnace and held at a final forging temperature of ≥380℃ for 25~75min. After forging, it is air-cooled to obtain a primary forging, which is then cleaned. S3, Secondary Forging Continue heating the cleaned primary forging to 470±10℃ and hold for 16~80min. Then, place the billet horizontally into the mold cavity for die forging. First, strike with a hammer with an energy of 15±5% of the total impact energy of the equipment. Then, remove the billet, clean the dirt in the mold cavity, and place the billet back into the mold cavity for die forging with an impact energy of 30±5% of the total impact energy of the equipment. Undervoltage: 0.5~1.

0. Return the hot material to the furnace and hold at a final forging temperature ≥380℃ for 8~40min. After forging, air cool to obtain the secondary forging. S4, Secondary Processing The secondary forging is placed in the cutting die and the edges are cut until the residual burrs on the secondary forging are ≤1.0mm, the wall thickness difference is ≤0.8mm, and the misalignment is ≤0.4mm; it is then cleaned and polished to remove defects, and the residual burrs on the cutting edge are polished until the residual burrs are ≤1.0mm, and then it is cleaned again. S5, Triple Forging Continue heating the cleaned secondary forging to 470±10℃ and hold for 10~80min. Place the secondary forging into the mold cavity according to the shape for die forging. The impact energy is 10%±5% of the total impact energy of the equipment. Return the hot material to the furnace and hold at the final forging temperature ≥380℃ for 5~40min. After forging, air cool to obtain the tertiary forging. S6, Three-stage processing The three-time forging is placed in the cutting die and the edges are cut until the residual burrs of the three-time forging are ≤1.0mm, the wall thickness difference is ≤0.8mm, and the misalignment is ≤0.4mm. It is then cleaned and ground until there are no defects, and the residual burrs of the cutting edge are ground until the residual burrs are ≤1.0mm. It is then cleaned again, and after solution treatment, correction, aging treatment, and second grinding, it is sent for inspection.

2. The forging method for an aero-engine fuel pump housing as described in claim 1, characterized in that, Before step S1, round the two ends of the blank to R3.

3. The forging method for an aero-engine fuel pump housing as described in claim 1, characterized in that, In steps S2, S4, and S5, the billet transfer time is ≤10s.

4. The forging method for an aero-engine fuel pump housing as described in claim 1, characterized in that, The cleaning process involves removing grease and dirt from the surface of the forging, with a removal amount ≤0.02mm.

5. The forging method for an aero-engine fuel pump housing as described in claim 1, characterized in that, In step S6, the solution treatment temperature is 1080~1120℃, the heating rate is 3~5℃ / min, and the holding time is 1~3h.

6. The forging method for an aero-engine fuel pump housing as described in claim 1, characterized in that, The correction method described in step S6 is as follows: lay a flat steel plate on the flat position of the mold base and adjust the upper and lower gap: H=8.5±0.2mm; before correction, clean the impurities and oil stains on the surface of the upper and lower plate positions, and then place the forging on the mold base for correction. The impact energy is 3%±5% of the total impact energy of the equipment.

7. The forging method for an aero-engine fuel pump housing as described in claim 1, characterized in that, In step S6, the aging process is performed in three stages, combining intermittent vibration aging with pulsed current processing. First stage: The cold-pressed forgings are held at 100~110℃ for 5~7h, and then pulsed current is applied at a frequency of 20000~25000Hz, a voltage of 30~50V, and a current density of 60~100A / mm for 30~50min. During the 30~70% of the current density application time, spectrum harmonic vibration aging treatment is performed. Second stage: Adjust the frequency of the pulse current to 15000~20000Hz, keep the voltage, current density and application time unchanged, and continue to perform spectrum harmonic vibration aging treatment for 40~60% of the current density application time. The third stage: Adjust the pulse voltage to 10~30V, the current density to 5~40A / mm, keep the applied frequency and application time unchanged, and continue to perform spectral harmonic vibration aging treatment for 20~80% of the current density application time.

8. The forging method for an aero-engine fuel pump housing as described in claim 7, characterized in that, The parameters for the spectral harmonic vibration aging treatment are: frequency 200~1000Hz, vibration time 5~15min, vibration number 3~10 times, and after each spectral harmonic vibration aging treatment, 2~4mL / cm 2 The treatment liquid is sprayed onto the surface of the three forgings in a certain amount of spraying volume. Then, the same extrusion pressure is applied to the three forgings in the transverse / longitudinal / axial direction in sequence. The extrusion pressure in the first stage is 100~150MPa, the extrusion pressure in the second stage is 120~150% of the first stage, and the extrusion pressure in the third stage is 30~50% of the second stage. The treatment solution comprises, by mass percentage, 25-35% agar, 3-7% water-based graphite lubricant, 6-10% chitosan, and the balance being an aqueous solution containing 8-12 wt% hydroxyl phosphoric acid.

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