Production method of main sliding cylinder die forging of undercarriage system for airplane

Abstract

The invention discloses a production method of a main sliding cylinder die forging of an undercarriage system for an airplane, and relates to the technical field of forging. According to the specific technical scheme, the method comprises the steps of forging-changing heating, forging-changing forging, blank making heating, blank making forging, rough pressure heating, rough pressure forging, primary trimming, primary corrosive washing damage repairing, pre-forging heating, pre-forging forging, secondary trimming, secondary corrosive washing damage repairing, final forging heating, final forging forging, third corrosive washing damage repairing, annealing, machining, solution treatment and aging treatment. The method comprises the steps of forging-changing heating, forging-changing forging, blank making heating, blank making forging, rough pressure heating, rough pressure forging, primary trimming, primary corrosive washing damage repairing, pre-forging heating, pre-forging forging, secondary trimming, secondary corrosive washing damage repairing, final forging heating, final forging forging, third corrosive washing damage repairing, annealing, machining, solution treatment and aging treatment. According to the production process for the main sliding cylinder die forging of the undercarriage system for the airplane, the main sliding cylinder die forging which is good in comprehensive performance, small in machining amount and stable in quality can be produced, the main sliding cylinder die forging can replace an imported die forging, and the use requirement of a commercial airplane is met.

Description

Technical Field

[0001] The invention belongs to the technical field of alloy forging, and in particular relates to a production method for a main slide die forging of an aircraft landing gear system. Background Art

[0002] The main slide in the landing gear system of domestic commercial aircraft generally uses imported forgings for processing parts, which has a large processing volume, high cost, long processing cycle, easy deformation, and all imported forgings from foreign suppliers are processed, which is easy to be unable to purchase due to international policies and other factors. At present, domestically developed commercial aircraft have entered the mass production stage, so it is necessary to use more economical and better comprehensive performance main slide die forgings for processing parts, which is also an inevitable requirement for responding to the localization of materials.

[0003] Therefore, how to effectively improve the processing efficiency and performance of the main slide of the aircraft landing gear system is a technical problem that people in this field need to solve at present. Summary of the invention

[0004] Based on the above background, the purpose is to provide a production process method for the main slide die forgings of the aircraft landing gear system, which is used to improve the comprehensive performance of the main slide die forgings and meet the use requirements.

[0005] In view of this, according to one aspect of an embodiment of the present invention, a method for producing a main slide die forging for an aircraft landing gear system is provided, comprising:

[0006] Step S01: forging heating: heating the upper and lower flat anvils and the elongated anvil, and heating the 7050 alloy ingot to 430-450° C., and keeping the temperature for 770-1440 minutes;

[0007] Step S02: reforging: reforging the ingot using the heated upper and lower flat anvils and the drawing anvil; the starting forging temperature is ≥410°C, the final forging temperature is ≥380°C, and the mold temperature is ≥250°C to form a blank;

[0008] Step S03: Blank making heating: heating the upper and lower flat anvils and the elongated anvil, and heating the blank to 430-450° C., and keeping the temperature for 380-1440 minutes;

[0009] Step S04: Blank forging: Use the heated upper and lower flat anvils and the drawing anvil to blank the blank, and complete the forging of the special-shaped blank within two fires; the starting forging temperature is ≥410°C, the final forging temperature is ≥380°C, and the mold temperature is ≥250°C;

[0010] Step S05: rough pressing heating: heating the rough pressing die and heating the special-shaped blank to 430-450° C. for 380-990 minutes;

[0011] Step S06: rough die forging: rough die forging the special-shaped blank with a rough die; the start forging temperature is ≥410°C, the final forging temperature is ≥380°C, the die temperature is ≥350°C, and lifting and lubrication are performed multiple times during the die closing process;

[0012] Step S07: primary trimming: trimming the burrs of the special-shaped blank after rough forging, with the burr residue ≤5mm, and the burr residue of the local burrs is allowed to be ≤30mm, and the sharp corners are polished and blunted;

[0013] Step S08: primary etching, cleaning and repairing: the special-shaped blank after the primary trimming is cleaned with acid and alkali, and then polished and repaired;

[0014] Step S09: pre-forging heating: heating the pre-forging die, and heating the shaped blank after the first etching, cleaning and repairing to 430-450° C., and keeping the temperature for 380-900 minutes;

[0015] Step S10: pre-forging: pre-forging the heated special-shaped blank with a pre-forging die; the start forging temperature is ≥410°C, the final forging temperature is ≥380°C, the die temperature is ≥350°C, and lifting and lubrication are performed at least once during the die closing process;

[0016] Step S11: Secondary trimming: remove the burrs of the pre-forged special-shaped blank, the burr residue is ≤5mm, the burr residue of the local burrs is allowed to be ≤30mm, and the sharp corners are polished and blunted;

[0017] Step S12: secondary etching and cleaning: cleaning the special-shaped blank after secondary trimming with acid and alkali, and performing grinding and repairing;

[0018] Step S13: final forging heating: heating the final forging die and heating the blank to 430-450° C. for 340-900 minutes;

[0019] Step S14: Final forging: final forging is performed on the heated special-shaped blank by using a final forging die; the start forging temperature is ≥410°C, the final forging temperature is ≥380°C, the die temperature is ≥350°C, and lifting and lubrication are performed at least once during the die closing process to form a forging;

[0020] Step S15: three-time etching and repairing: acid and alkali cleaning of the final forging and grinding and repairing;

[0021] Step S16: Annealing: annealing the forged parts after three etching and repairing, with the temperature set at 471±5°C, the heating medium being air, and cooling them with air after the heat preservation is completed;

[0022] Step S17 machining: machining the annealed forging according to design requirements to reduce its heat treatment thickness;

[0023] Step S18: Solution treatment: The machined forgings are subjected to solution treatment at a constant temperature of 471±5°C for 320 minutes. The heating medium is air. After the insulation is completed, the forgings are taken out of the furnace for water quenching. The quenching water temperature is 54-71°C, and the maximum transfer time does not exceed 15 seconds.

[0024] Step S19: Aging treatment: The forging is aged within 72 hours after solution treatment. The first stage of the aging system is 121±5°C, and the temperature is kept at 420 minutes. The second stage is 177±5°C, and the temperature is kept at 480 minutes. The heating medium is air. After the insulation is completed, the forging is cooled by air to form the main slide die forging of the aircraft landing gear system.

[0025] Optionally, the chemical composition of the 7050 alloy ingot includes: 2.2-2.5% Cu, 2.25-2.55% Mg, 6.25-6.60% Zn, 0.03-0.06% Ti, 0.11-0.13% Zr, and the liquid hydrogen content is ≤0.1ml / 100gAL.

[0026] Optionally, flaw detection is also included after step S02 and / or step S16.

[0027] Optionally, step S06 also includes: placing the special-shaped blank in the center of the rough pressing mold, setting the mold to zero position, pressing from a mold height of 270mm at a downward pressing speed of 5mm / s to 60mm and then lifting it up for lubrication, pressing from a mold height of 70mm at a downward pressing speed of 2mm / s to 20mm and then lifting it up for lubrication, and pressing from a mold height of 30mm at a downward pressing speed of 1mm / s to 1~7mm.

[0028] Optionally, step S10 also includes: placing the pre-forged heated special-shaped blank in the center of the pre-forging die, setting the die to zero position, pressing from a die height of 100 mm at a downward pressing speed of 5 mm / s and a strain rate coefficient of 0.04 to 15 mm, then lifting and lubricating, and pressing from a die height of 25 mm at a downward pressing speed of 1 mm / s to 0-4 mm.

[0029] Optionally, step S14 also includes: placing the final forging heated special-shaped blank in the center of the final forging die, setting the die to zero position, pressing from a die height of 85 mm at a downward pressing speed of 4 mm / s and a strain rate coefficient of 0.04 to 10 mm, then lifting and lubricating, and pressing from a die height of 20 mm at a downward pressing speed of 1 mm / s to 0-5 mm.

[0030] Optionally, step S02 also includes: the reforging includes two firings, the first firing includes two upsetting and two drawing, and the second firing includes one upsetting and one drawing.

[0031] Optionally, it also includes: when the blank is cut, the edge chamfer is ≥ R5 or C5, and the sawing surface roughness is Ra12.5.

[0032] The production process of the main slide die forgings for the aircraft landing gear system of the present invention can produce main slide forgings with good comprehensive performance, small processing volume and stable quality, which can replace imported forgings and meet the use requirements of commercial aircraft. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 is a first side structural schematic diagram of a main slide forging for an aircraft provided by an embodiment of the present invention;

[0034] Figure 2 is a second side structural schematic diagram of a main slide forging for an aircraft provided by an embodiment of the present invention;

[0035] Figure 3 The embodiment of the present invention provides a structure and detection position diagram of a blank forging;

[0036] Figure 4 The structure and detection position diagram of the rough forging provided by the embodiment of the present invention;

[0037] Figure 5 The present invention provides a structure and detection position diagram of a pre-forged forging according to an embodiment of the present invention;

[0038] Figure 6 The embodiment of the present invention provides a structure and detection position diagram of the final forging;

[0039] Figure 7 It is a schematic diagram of the structure of the pre-heat treatment processing provided by the embodiment of the present invention;

[0040] Figure 8 Schematic diagram of heat treatment and framing of a main slide forging for an aircraft according to an embodiment of the present invention;

[0041] Description of reference numerals:

[0042] 1-main slide die forging, 2-blank cutting position, 201-blank blank sample, 3-rough pressure detection point, 4-pre-forging detection point, 5-final forging detection point, 6-forging heat treatment maximum thickness position, 7-material frame. DETAILED DESCRIPTION

[0043] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0044] According to one aspect of an embodiment of the present invention, a method for producing a main slide die forging for an aircraft landing gear system is provided, comprising:

[0045] Step S01: forging heating: heating the upper and lower flat anvils and the elongated anvil, and heating the 7050 alloy ingot to 430-450° C., and keeping the temperature for 770-1440 minutes;

[0046] Step S02: reforging: reforging the ingot using the heated upper and lower flat anvils and the drawing anvil; the starting forging temperature is ≥410°C, the final forging temperature is ≥380°C, and the mold temperature is ≥250°C to form a blank;

[0047] Step S03: Blank making heating: heating the upper and lower flat anvils and the elongated anvil, and heating the blank to 430-450° C., and keeping the temperature for 380-1440 minutes;

[0048] Step S04: Blank forging: Use the heated upper and lower flat anvils and the drawing anvil to blank the blank, and complete the forging of the special-shaped blank within two fires; the starting forging temperature is ≥410°C, the final forging temperature is ≥380°C, and the mold temperature is ≥250°C;

[0049] Step S05: rough pressing heating: heating the rough pressing die and heating the special-shaped blank to 430-450° C. for 380-990 minutes;

[0050] Step S06: rough die forging: rough die forging the special-shaped blank with a rough die; the start forging temperature is ≥410°C, the final forging temperature is ≥380°C, the die temperature is ≥350°C, and lifting and lubrication are performed multiple times during the die closing process;

[0051] Step S07: primary trimming: trimming the burrs of the special-shaped blank after rough forging, with the burr residue ≤5mm, and the burr residue of the local burrs is allowed to be ≤30mm, and the sharp corners are polished and blunted;

[0052] Step S08: primary etching, cleaning and repairing: the special-shaped blank after the primary trimming is cleaned with acid and alkali, and then polished and repaired;

[0053] Step S09: pre-forging heating: heating the pre-forging die, and heating the shaped blank after the first etching, cleaning and repairing to 430-450° C., and keeping the temperature for 380-900 minutes;

[0054] Step S10: pre-forging: pre-forging the heated special-shaped blank with a pre-forging die; the start forging temperature is ≥410°C, the final forging temperature is ≥380°C, the die temperature is ≥350°C, and lifting and lubrication are performed at least once during the die closing process;

[0055] Step S11: Secondary trimming: remove the burrs of the pre-forged special-shaped blank, the burr residue is ≤5mm, the burr residue of the local burrs is allowed to be ≤30mm, and the sharp corners are polished and blunted;

[0056] Step S12: secondary etching and cleaning: cleaning the special-shaped blank after secondary trimming with acid and alkali, and performing grinding and repairing;

[0057] Step S13: final forging heating: heating the final forging die and heating the blank to 430-450° C. for 340-900 minutes;

[0058] Step S14: Final forging: final forging is performed on the heated special-shaped blank by using a final forging die; the start forging temperature is ≥410°C, the final forging temperature is ≥380°C, the die temperature is ≥350°C, and lifting and lubrication are performed at least once during the die closing process to form a forging;

[0059] Step S15: three-time etching and repairing: acid and alkali cleaning of the final forging and grinding and repairing;

[0060] Step S16: Annealing: annealing the forged parts after three etching and repairing, with the temperature set at 471±5°C, the heating medium being air, and cooling them with air after the heat preservation is completed;

[0061] Step S17 machining: machining the annealed forging according to design requirements to reduce its heat treatment thickness;

[0062] Step S18: Solution treatment: The machined forgings are subjected to solution treatment at a constant temperature of 471±5°C for 320 minutes. The heating medium is air. After the insulation is completed, the forgings are taken out of the furnace for water quenching. The quenching water temperature is 54-71°C, and the maximum transfer time does not exceed 15 seconds.

[0063] Step S19: Aging treatment: The forging is aged within 72 hours after solution treatment. The first stage of the aging system is 121±5°C, and the temperature is kept at 420 minutes. The second stage is 177±5°C, and the temperature is kept at 480 minutes. The heating medium is air. After the insulation is completed, the forging is cooled by air to form the main slide die forging of the aircraft landing gear system.

[0064] Furthermore, the chemical composition of the 7050 alloy ingot includes: 2.2-2.5% Cu, 2.25-2.55% Mg, 6.25-6.60% Zn, 0.03-0.06% Ti, 0.11-0.13% Zr, and the liquid hydrogen content is ≤0.1ml / 100gAL.

[0065] Furthermore, flaw detection is also included after step S02 and / or step S16.

[0066] Furthermore, step S06 also includes: placing the special-shaped blank in the center of the rough pressing mold, setting the mold to zero position, pressing from a mold height of 270mm at a downward pressing speed of 5mm / s to 60mm and then lifting it up for lubrication, pressing from a mold height of 70mm at a downward pressing speed of 2mm / s to 20mm and then lifting it up for lubrication, and pressing from a mold height of 30mm at a downward pressing speed of 1mm / s to 1~7mm.

[0067] Furthermore, step S10 also includes: placing the pre-forged heated special-shaped blank in the center of the pre-forging die, setting the die to zero position, pressing from a die height of 100 mm at a pressing speed of 5 mm / s and a strain rate coefficient of 0.04 to 15 mm, then lifting and lubricating, and pressing from a die height of 25 mm at a pressing speed of 1 mm / s to 0-4 mm.

[0068] Furthermore, step S14 also includes: placing the final forging heated special-shaped blank in the final forging die, setting the die to zero position, pressing from a die height of 85 mm at a pressing speed of 4 mm / s and a strain rate coefficient of 0.04 to 10 mm, then lifting and lubricating, and pressing from a die height of 20 mm at a pressing speed of 1 mm / s to 0-5 mm.

[0069] Furthermore, step S02 also includes: the reforging includes two firings, the first firing includes two upsetting and two drawing, and the second firing includes one upsetting and one drawing.

[0070] Furthermore, it also includes: when the blank is cut, the edge chamfer is ≥ R5 or C5, and the sawing surface roughness is Ra12.5.

[0071] Example 1

[0072] In order to enable those skilled in the art to better solve the present application, the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0073] Please refer to Figures 1 to 8 , Figure 1 is a first side structural schematic diagram of a main slide forging for an aircraft provided by an embodiment of the present invention; Figure 2 is a second side structural schematic diagram of a main slide forging for an aircraft provided by an embodiment of the present invention; Figure 3 The embodiment of the present invention provides a structure and detection position diagram of a blank forging; Figure 4 The structure and detection position diagram of the rough forging provided by the embodiment of the present invention; Figure 5 The present invention provides a structure and detection position diagram of a pre-forged forging according to an embodiment of the present invention; Figure 6 The embodiment of the present invention provides a structure and detection position diagram of the final forging; Figure 7 It is a schematic diagram of the structure of the pre-heat treatment processing provided by the embodiment of the present invention; Figure 8It is a schematic diagram of heat treatment framing of a main slide forging for an aircraft according to an embodiment of the present invention.

[0074] In this embodiment, the production process of the main slide die forging 1 for an aircraft landing gear system includes the following steps:

[0075] Ingot acceptance → unloading → reforging and heating → reforging and forging → ultrasonic flaw detection → billet heating → billet forging → slitting → rough pressing heating → rough pressing forging → trimming → etching and repairing → pre-forging heating → pre-forging and forging → trimming → etching and repairing → final forging heating → final forging → etching and repairing → annealing → ultrasonic flaw detection → machining → solution treatment → aging → testing → acceptance.

[0076] Specifically, the step of "forging heating" includes: heating the upper and lower flat anvils in a mold heating furnace, and heating the ingot to 430-450° C., and keeping the temperature for 770-1440 minutes;

[0077] The step of "blank heating" includes: heating the upper and lower flat anvils in a mold heating furnace, and heating the blank to 430-450° C., and keeping the temperature for 380-1440 minutes;

[0078] The step of "rough pressing heating" includes: heating the rough pressing die in a die heating furnace, and heating the blank to 430-450° C., and keeping the temperature for 380-990 minutes;

[0079] The step of "pre-forging heating" includes: heating the pre-forging die in a die heating furnace, heating the blank to 430-450° C., and keeping the temperature for 380-900 minutes;

[0080] The step of "final forging heating" includes: heating the final forging die in a die heating furnace, heating the blank to 430-450° C., and keeping the temperature for 340-900 minutes.

[0081] Based on the above embodiments, the step "ingot acceptance" includes: obtaining a 7050 alloy ingot, size: The chemical composition element content is: Cu (2.2-2.5%), Mg (2.25-2.55%), Zn (6.25-6.60%), Ti (0.03-0.06%), Zr (0.11-0.13%), and the liquid hydrogen content in the ingot alloy is ≤0.1ml / 100gAL;

[0082] Step "cutting" includes: machining and sawing the ingot to size

[0083] The step of "reforging" includes: using a 2500-ton free forging hydraulic press to reforge the ingot using upper and lower flat anvils and a drawing anvil; the start forging temperature is ≥410℃, the final forging temperature is ≥380℃, and the mold temperature is ≥250℃. The start and end forging temperatures are measured and recorded piece by piece. The entire reforging process includes two fires, the first fire is two upsetting and two drawing, and the second fire is one upsetting and one drawing.

[0084] The step of "blanket forging" includes: a 2500-ton free forging hydraulic press is used to form the blank using upper and lower flat anvils and a drawing anvil, and the forging of the special-shaped blank is completed within two fires; the start forging temperature is ≥410°C, the final forging temperature is ≥380°C, the mold temperature is ≥250°C, the start forging and final forging temperatures are measured and recorded piece by piece, and a special blank sample 201 is used for measurement.

[0085] Step "slitting" includes: sawing machine, sawing the blank into two pieces for splitting, edge chamfering ≥ R5 or C5, grinding the sawn surface, requiring the sawn surface roughness Ra12.5, and no sawing marks are allowed. Figure 3 The blank cutting position 2 is shown.

[0086] The step of "rough forging" includes: using a 12,500-ton die forging hydraulic press and a rough die to perform rough die forging on the blank; the starting forging temperature is ≥410°C, the final forging temperature is ≥380°C, the die temperature is ≥350°C, and the starting and final forging temperatures are measured and recorded piece by piece; the blank is placed in the rough die, and the blank is placed in the center; the die is closed and set to zero position, from a die height of 270mm, press at a speed of 5mm / s to 60mm, then lift up for lubrication, from a die height of 70mm, press at a speed of 2mm / s to 20mm, then lift up for lubrication, and from a die height of 30mm, press at a speed of 1mm / s to 1-7mm. Figure 4 As shown, the mold closing height is measured based on the position of the gross pressure detection point 3.

[0087] The step of "pre-forging" includes: using a 12,500-ton die forging hydraulic press and a pre-forging die to pre-forge the blank; the starting forging temperature is ≥410°C, the final forging temperature is ≥380°C, the die temperature is ≥350°C, and the initial and final forging temperatures are measured and recorded piece by piece; the blank is placed in the pre-forging die, and the blank is placed in the center; the die is closed and set to zero position, from the die height of 100mm, the pressing speed is 5mm / s, the strain rate coefficient is 0.04, and it is pressed to 15mm, then lifted and lubricated, and from the die height of 25mm, the pressing speed is 1mm / s to 0-4mm. Figure 5 As shown, the mold closing height is measured according to the position of the pre-forging detection point 4.

[0088] The step of "final forging" includes: using a 12,500-ton die forging hydraulic press and a final forging die to perform final forging on the billet; the start forging temperature is ≥410°C, the final forging temperature is ≥380°C, the die temperature is ≥350°C, and the initial and final forging temperatures are measured and recorded piece by piece; the billet is placed in the final forging die, and the billet is placed in the center; the die is closed and set to zero position, and from the die height of 85mm, the pressing speed is 4mm / s, and the strain rate coefficient is 0.04, and the pressure is pressed to 10mm, then lifted and lubricated, and from the die height of 20mm, the pressing speed is 1mm / s to 0-5mm. Figure 6 As shown, the mold closing height is measured according to the position of the final forging detection point 5.

[0089] The step "solid solution" includes: using a vertical aluminum alloy electric heating heat treatment furnace, using a special material frame 7 to load the material into the frame, the spacing between each forging is more than 150mm, and the maximum number of forgings per furnace is not more than 9; the furnace temperature is stabilized at 471±5℃ before loading the furnace; the maximum heat treatment thickness of the forging is 113.8mm, such as Figure 7 The maximum thickness position of the forging heat treatment shown is 6; constant temperature: 471±5, the forging is kept warm for 320min, the heating medium is air, and after the insulation is completed, it is taken out of the furnace for water quenching, the quenching water temperature is 54~71℃, the maximum transfer time does not exceed 15s, and it must be recorded truthfully; aging treatment must be carried out within 72 hours after solution treatment.

[0090] The step "aging" includes: using a double-trolley aluminum alloy electric heating heat treatment furnace for aging, placing the forgings in a special material frame 7, and each forging is spaced more than 150 mm apart; aging system: the first stage is 121±,5, and insulation is 420 minutes; the second stage is 177±5, and insulation is 480 minutes; the heating medium is air, and after the insulation is completed, the forgings are taken out of the furnace and air-cooled.

[0091] The step of "etching and repairing" includes: acid and alkali cleaning of the forging, observing the surface quality of the forging, and grinding and repairing, which can be repeated until all defects are removed.

[0092] The step of "trimming" includes: machining and removing burrs according to the requirements of the drawings and digital models, with the burr residue ≤5mm, and the burr residue of local burrs is allowed to be ≤30mm, and sharp corners and edges need to be polished and blunted.

[0093] The step "machining" includes: machining the forgings according to the drawings and digital model requirements to reduce the heat treatment thickness.

[0094] Example 2

[0095] The production process of the main slide die forging of the aircraft landing gear system includes the following steps:

[0096] Step 1) Ingot acceptance: Ingot specifications: 7050 alloy; chemical composition element content: Cu (2.2 ~ 2.5%), Mg (2.25 ~ 2.55%), Zn (6.25 ~ 6.60%), Ti (0.03 ~ 0.06%), Zr (0.11 ~ 0.13%), and the liquid hydrogen content in the ingot alloy is ≤ 0.1ml / 100gAL

[0097] Step 2) Cutting: Cut the ingot to size Mark: batch number, ingot number.

[0098] Step 3) Forging heating: the upper and lower flat anvils and the drawing anvil of the mold are heated to a fixed temperature of 400°C for ≥10 hours, and the ingot is heated to 440±10°C for 770-1440 minutes;

[0099] Step 4) Forging: 2500 ton free forging hydraulic press equipped with upper and lower flat anvils and long anvils, start forging temperature ≥410℃, final forging temperature ≥350℃, die temperature ≥250℃, measure and record the start forging temperature, final forging temperature and die temperature piece by piece; three upsetting and three drawing, a total of 2 fires, the finished product size is about 298×680×950mm;

[0100] Step 5) Ultrasonic flaw detection: Process the upper and lower surfaces of the forging, remove the excess evenly during processing, the thickness after processing is 283+3mm, and the surface roughness after processing is Ra6.3; the upper and lower surfaces are subjected to contact flaw detection according to Class A in standard AMS-STD-2154.

[0101] Step 6) Blank heating: the upper and lower flat anvils and the drawing anvil of the mold are heated to a fixed temperature of 400°C for ≥10 hours, the blanks are heated to 440±10°C, and kept warm for 380-1440 minutes, and the blank spacing is ≥200mm;

[0102] Step 7) Billet forging: 2500 ton free forging hydraulic press equipped with upper and lower flat anvils and drawing anvils, start forging temperature ≥410℃, final forging temperature ≥350℃, die temperature ≥250℃, measure and record the start forging temperature, final forging temperature and die temperature piece by piece; heterogeneous step plate, completed within 2 fires, use special template and forging drawing size to control the outer dimensions, the overlap size between the billet and the template: +30 / -15mm;

[0103] Step 8) Cutting: Cut the blank into two pieces according to the drawing, with edge chamfer ≥ R5 or C5, sawing surface roughness Ra12.5, and no sawing marks are allowed.

[0104] Step 9) Blank pressing heating: Blank pressing mold is heated to a fixed temperature of 450°C for ≥12 hours, blanks are heated to 440±10°C for 380-900 minutes, and the blank spacing is ≥150mm;

[0105] Step 10) Rough forging: Use a 12500 ton die forging hydraulic press and a rough die to perform rough die forging on the blank; the start forging temperature is ≥410°C, the final forging temperature is ≥380°C, the die temperature is ≥350°C, and the initial and final forging temperatures are measured and recorded piece by piece; the blank is placed in the rough die, and the blank is placed in the center; the die is closed and set to zero position, and from a die height of 270mm, it is pressed at a downward speed of 5mm / s to 60mm and then lifted for lubrication, from a die height of 70mm, it is pressed at a downward speed of 2mm / s to 20mm and then lifted for lubrication, and from a die height of 30mm, it is pressed at a downward speed of 1mm / s to 1-7mm;

[0106] Step 11) Trimming: According to the requirements of the drawing and the digital model, the burrs are removed. The residual burrs are ≤5mm. The residual burrs of local burrs are allowed to be ≤30mm. Sharp corners and edges need to be polished and blunted.

[0107] Step 12) Etching and repairing: Clean the forgings with acid and alkali, observe the surface quality of the forgings, and perform grinding and repairing. This process can be repeated until all defects are removed.

[0108] Step 13) Pre-forging heating: the pre-forging die is heated to a fixed temperature of 450°C for ≥12 hours, the blank is heated to 440±10°C for 330-900 minutes, and the blank spacing is ≥150mm.

[0109] Step 14) Pre-forging: Use a 12500 ton die forging hydraulic press and a pre-forging die to pre-forge the blank; the start forging temperature is ≥410°C, the final forging temperature is ≥380°C, the die temperature is ≥350°C, and the initial and final forging temperatures are measured and recorded piece by piece; the blank is placed in the pre-forging die, and the blank is placed in the center; the die is closed and set to zero position, and from a die height of 100mm, the pressing speed is 5mm / s, and the strain rate coefficient is 0.04, it is pressed to 15mm, then lifted and lubricated, and from a die height of 25mm, the pressing speed is 1mm / s to 0-4mm.

[0110] Step 15) Trimming: according to the drawing and the requirements of the digital model, the burrs shall be removed, the residual burrs shall be ≤5mm, the residual burrs of local burrs shall be ≤30mm, and the sharp edges shall be polished and blunted.

[0111] Step 16) Etching and repairing: Clean the forgings with acid and alkali, observe the surface quality of the forgings, and perform grinding and repairing. This process can be repeated until all defects are removed.

[0112] Step 17) Final forging heating: the final forging die is heated to a fixed temperature of 450°C for ≥12 hours, the billet is heated to 440±10°C and kept warm for 340-900 minutes, and the distance between the billets is ≥150mm.

[0113] Step 18) Final forging: Use a 12500 ton die forging hydraulic press and a final forging die to perform final forging on the billet; the start forging temperature is ≥410°C, the final forging temperature is ≥380°C, the die temperature is ≥350°C, and the initial and final forging temperatures are measured and recorded piece by piece; the billet is placed in the final forging die, and the billet is placed in the center; the die is closed and set to zero position, and from a closing height of 85mm, the pressing speed is 4mm / s, and the strain rate coefficient is 0.04, it is pressed to 10mm, then lifted and lubricated, and from a closing height of 20mm, the pressing speed is 1mm / s to 0-5mm.

[0114] Step 19) Etching and repairing: Clean the forgings with acid and alkali, observe the surface quality of the forgings, and perform grinding and repairing. This process can be repeated until all defects are removed.

[0115] Step 20) Annealing: adopt a trolley-type aluminum alloy electric heating heat treatment furnace, use a special material frame to load the material into the frame, each forging is spaced more than 150mm apart, and the maximum number of forgings per furnace is not more than 10; the furnace temperature is stabilized at 471±5℃ before loading; the maximum heat treatment thickness of the forging is 246.7mm; fixed temperature: 471±5, take a thermocouple and place it at the thickest section of the forging, and the forging is kept warm for 670min according to the thermocouple. The heating medium is air, and after the insulation is completed, it is taken out of the furnace and air-cooled.

[0116] Step 21) Ultrasonic testing: Conduct contact testing on the forging body according to the schematic diagram, and conduct inspection and acceptance according to Class A in standard AMS-STD-2154.

[0117] Step 22) Machining: Machining the forgings according to the machining drawing, removing burrs and sharp corners, the unmarked dimensional tolerance is ±2mm, and the surface roughness of the machined part is Ra6.3.

[0118] Step 23) Solution treatment: adopt a vertical aluminum alloy electric heating heat treatment furnace, use a special material frame to load the material into the frame, each forging is more than 150mm apart, and the maximum number of forgings per furnace is not more than 5; the furnace temperature is stabilized at 471±5℃ and the furnace is loaded; the maximum heat treatment thickness of the forging is 113.8mm; fixed temperature: 471±5, the forging is kept warm for 320min, the heating medium is air, and after the insulation is completed, it is taken out of the furnace for water quenching, the quenching water temperature is 54~71℃, the maximum transfer time does not exceed 15s, and it is recorded truthfully; aging treatment must be carried out within 72 hours after solution treatment.

[0119] Step 24) Aging: A double-trolley aluminum alloy electric heating heat treatment furnace is used for aging. The forgings are placed in a special material frame. The spacing between each forging is more than 150mm. The maximum number of forgings per furnace is not more than 10. Aging system: the first stage is 121±,5, and the insulation is 420min; the second stage is 177±5, and the insulation is 480min. The heating medium is air, and the furnace is air-cooled after the insulation is completed.

[0120] Step 25) Detection:

[0121] Mechanical properties (tensile) testing is carried out on tensile specimens: testing is carried out in accordance with the requirements of ASTM E8 / E8M.

[0122] Stress corrosion testing is carried out on stress corrosion specimens: the test is carried out in accordance with the requirements of ASTM G47.

[0123] Hardness test is carried out on the forging body: the test is carried out according to the requirements of ASTM E10.

[0124] Fatigue testing was performed on fatigue specimens: Testing was performed in accordance with the requirements of ASTM E466.

[0125] Streamline testing is performed on low-magnification streamline specimens: Testing is performed in accordance with the requirements of ASTM E340.

[0126] Grain size test is carried out on grain size specimens: the test is carried out in accordance with the requirements of ASTM E340.

[0127] The fracture toughness test was carried out on the fracture toughness specimens: the test was carried out according to the requirements of ASTM E399.

[0128] Step 26) Acceptance: Acceptance is carried out according to the forging inspection plan and forging drawings; inventory and inspection of part appearance; check the integrity of process records and quality documents.

[0129] The production process of the main slide die forgings for the aircraft landing gear system provided in this embodiment can produce main slide forgings with good comprehensive performance, small processing volume and stable quality, which can replace imported forgings and meet the use requirements of commercial aircraft.

[0130] The above is only a specific embodiment of the present invention, and the present invention is described in detail. The unexplained part is a conventional technology. However, the protection scope of the present invention is not limited to this. Any changes or substitutions that can be easily thought of by any technician familiar with the technical field within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. The protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A method for producing a main slide die forging for an aircraft landing gear system, characterized in that: include: Step S01: forging heating: heating the upper and lower flat anvils and the elongated anvil, and heating the 7050 alloy ingot to 430-450° C., and keeping the temperature for 770-1440 minutes; Step S02: reforging: reforging the ingot using the heated upper and lower flat anvils and the drawing anvil; the starting forging temperature is ≥410°C, the final forging temperature is ≥380°C, and the mold temperature is ≥250°C to form a blank; Step S03: Blank making heating: heating the upper and lower flat anvils and the elongated anvil, and heating the blank to 430-450° C., and keeping the temperature for 380-1440 minutes; Step S04: Blank forging: Use the heated upper and lower flat anvils and the drawing anvil to blank the blank, and complete the forging of the special-shaped blank within two fires; the starting forging temperature is ≥410°C, the final forging temperature is ≥380°C, and the mold temperature is ≥250°C; Step S05: rough pressing heating: heating the rough pressing die and heating the special-shaped blank to 430-450° C. for 380-990 minutes; Step S06: rough die forging: rough die forging the special-shaped blank with a rough die; the start forging temperature is ≥410°C, the final forging temperature is ≥380°C, the die temperature is ≥350°C, and lifting and lubrication are performed multiple times during the die closing process; Step S07: primary trimming: trimming the burrs of the special-shaped blank after rough forging, with the burr residue ≤5mm, and the burr residue of the local burrs is allowed to be ≤30mm, and the sharp corners are polished and blunted; Step S08: primary etching, cleaning and repairing: the special-shaped blank after the primary trimming is cleaned with acid and alkali, and then polished and repaired; Step S09: pre-forging heating: heating the pre-forging die, and heating the shaped blank after the first etching, cleaning and repairing to 430-450° C., and keeping the temperature for 380-900 minutes; Step S10: pre-forging: pre-forging the heated special-shaped blank with a pre-forging die; the start forging temperature is ≥410°C, the final forging temperature is ≥380°C, the die temperature is ≥350°C, and lifting and lubrication are performed at least once during the die closing process; Step S11: Secondary trimming: remove the burrs of the pre-forged special-shaped blank, the burr residue is ≤5mm, the burr residue of the local burrs is allowed to be ≤30mm, and the sharp corners are polished and blunted; Step S12: secondary etching and cleaning: cleaning the special-shaped blank after secondary trimming with acid and alkali, and performing grinding and repairing; Step S13: final forging heating: heating the final forging die and heating the blank to 430-450° C. for 340-900 minutes; Step S14: Final forging: final forging is performed on the heated special-shaped blank by using a final forging die; the start forging temperature is ≥410°C, the final forging temperature is ≥380°C, the die temperature is ≥350°C, and lifting and lubrication are performed at least once during the die closing process to form a forging; Step S15: three-time etching and repairing: acid and alkali cleaning of the final forging and grinding and repairing; Step S16: Annealing: annealing the forged parts after three etching and repairing, with the temperature set at 471±5°C, the heating medium being air, and cooling them with air after the heat preservation is completed; Step S17 machining: machining the annealed forging according to design requirements to reduce its heat treatment thickness; Step S18: Solution treatment: The machined forgings are subjected to solution treatment at a constant temperature of 471±5°C for 320 minutes. The heating medium is air. After the insulation is completed, the forgings are taken out of the furnace for water quenching. The quenching water temperature is 54-71°C, and the maximum transfer time does not exceed 15 seconds. Step S19: Aging treatment: The forging is aged within 72 hours after solution treatment. The first stage of the aging system is 121±5°C, and the temperature is kept at 420 minutes. The second stage is 177±5°C, and the temperature is kept at 480 minutes. The heating medium is air. After the insulation is completed, the forging is cooled by air to form the main slide die forging of the aircraft landing gear system.

2. The method according to claim 1, characterized in that The chemical composition of the 7050 alloy ingot includes: 2.2-2.5% Cu, 2.25-2.55% Mg, 6.25-6.60% Zn, 0.03-0.06% Ti, 0.11-0.13% Zr, and the liquid hydrogen content is ≤0.1ml / 100gAL.

3. The method according to claim 1, characterized in that After step S02 and / or step S16, flaw detection is also included.

4. The method according to claim 1, characterized in that: Step S06 also includes: Place the special-shaped blank in the center of the rough pressing mold, set the mold to zero position, press from a mold height of 270mm at a downward pressing speed of 5mm / s to 60mm, then lift it up for lubrication, press from a mold height of 70mm at a downward pressing speed of 2mm / s to 20mm, then lift it up for lubrication, and press from a mold height of 30mm at a downward pressing speed of 1mm / s to 1-7mm.

5. The method according to claim 1, characterized in that Step S10 also includes: Place the pre-forged heated special-shaped blank in the center of the pre-forging die, set the die to zero position, press from a die height of 100mm at a downward pressing speed of 5mm / s and a strain rate coefficient of 0.04 to 15mm, then lift and lubricate, and press from a die height of 25mm at a downward pressing speed of 1mm / s to 0-4mm.

6. The method according to claim 1, characterized in that Step S14 also includes: The shaped blank after final forging heating is placed in the final forging die in the center, the die is closed and set to zero position, from the die height of 85mm, press at a speed of 4mm / s, strain rate coefficient of 0.04 to 10mm, then lift and lubricate, from the die height of 20mm, press at a speed of 1mm / s to 0-5mm.

7. The method according to claim 1, characterized in that Step S02 also includes: the reforging includes two firings, the first firing includes two upsetting and two drawing, and the second firing includes one upsetting and one drawing.

8. The method according to claim 1, characterized in that Also includes: When the blank is cut, the edge chamfer should be ≥ R5 or C5, and the sawing surface roughness should be Ra12.5.

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