Preparation method of square closed rib die forging for airplane

Abstract

The invention discloses a preparation method of a square closed rib die forging for an airplane, relates to a production method of the square closed rib die forging, and aims to solve the problem that a die forging obtained by an existing production process is easy to generate a cross-flow defect. The production method comprises the following steps: 1, preparing an aluminum alloy ingot; 2, heating and extruding the cast ingot into a strip plate; 3, flattening the heating belt plate; 4, heating for first die forging forming; 5, carrying out corrosive washing and rib milling treatment; 6, machining and drilling; 7, secondary die forging forming; 8, corrosive washing and damage repairing; 9, quenching and aging treatment; 10, total analysis detection; and 11, acceptance and delivery. According to the method, corrosive washing, rib milling treatment and machining drilling are added, meanwhile, the size of a flattened blank is controlled, and follow-up scientific control over the process conditions of compression molding is matched, so that the macrostructure of the obtained die forging does not have the cross-flow defect, and the purposes of improving the bearing capacity of the die forging and prolonging the service life of the die forging are achieved. The method is applied to the field of manufacturing of die forgings.

Description

Technical Field

[0001] The invention belongs to a method for preparing a U-shaped closed rib die forging for an aircraft. Background Art

[0002] With the rapid development of my country's aviation industry, the performance requirements for aluminum alloy structural parts are getting higher and higher. Every part of a transport aircraft is closely related to each other during flight, and every part is very important. The U-shaped closed rib die forgings are mainly made of AL-Cu-Si main element aluminum alloy. This type of alloy has the characteristics of compact structure, high strength, good heat resistance and processing performance, and is widely used in the aviation field. However, during the production process of the die forging, flow defects often occur in the U-shaped closed rib part. The die forging produces low-multiple flow quality defects, which will increase the probability of cracking of the aircraft's structural parts during flight. This phenomenon is absolutely not allowed to occur and must be scrapped. Therefore, reducing the probability of cracking of engine structural parts during flight has a wide range of promotion and application value in the aviation industry. Summary of the invention

[0003] The purpose of the present invention is to solve the problem that the die forgings obtained by the existing production process are prone to flow defects, and to provide a production method for the U-shaped closed rib die forgings for aircraft.

[0004] The method for preparing a U-shaped closed rib die forging for aircraft of the present invention is carried out by the following steps:

[0005] 1. According to the mass percentage of the elements: Cu is 1.8% to 2.6%; Mg is 0.4% to 0.8%; Si is 0.7% to 1.2%; Fe is ≤0.7%; Mn is 0.4% to 0.8%; Ni is ≤0.1%, Zn is ≤0.3%, Ti is ≤0.15% and the balance is Al to prepare an aluminum alloy round ingot, and then perform homogenization annealing;

[0006] 2. Extruding the aluminum alloy ingot after homogenization annealing to obtain a long plate-shaped blank with a specification of 35 mm×310 mm;

[0007] 3. The long plate-shaped blank is subjected to low-power and fracture microstructure inspection. After the inspection is qualified, it is sawed, forged and stretched, and then placed in a mold for the first die forging. The opening forging temperature is 440℃~460℃, and the mold temperature is 420℃ to obtain die forging A;

[0008] Fourth, the die forging A obtained in step 3 is repaired with a milling machine to repair the high ribs on the edge, and then the edges and corners are polished with a grinder, and a hole with a diameter of 60 to 80 mm is drilled in the center;

[0009] 5. The die forgings processed in step 4 are heated, the start forging temperature is controlled to be 440° C. to 460° C., the final forging temperature is controlled to be 410° C. to 430° C., and after cleaning, they are die forged for the second time to obtain die forgings B;

[0010] 6. etching and repairing the die forging B obtained in step 5 to obtain an etched die forging;

[0011] 7. After the die forgings have been etched and washed, they are quenched and then subjected to aging treatment to complete the production of the die forgings.

[0012] In the present invention, when a hole is drilled in the middle of the middle part of the die forging, the middle metal is machined out during the first die forging, and during the second die forging, part of the metal fills the cavity, and part of the metal flows to the hole for filling. Since the metal fills the cavity again, there is no resistance in the cavity part, and there is no resistance at the hole, the metal can easily fill the cavity, and the streamline of the metal is completely along the direction of the cavity, achieving a good effect. When the die forgings produced by the process of the present invention are subjected to macroscopic structural comparison analysis, it is found that the macroscopic structural of the die forgings does not have flow defects, thereby achieving the purpose of improving the bearing capacity of the die forgings and the service life of the die forgings.

[0013] The U-shaped closed rib die forging of the present invention can be applied in the actual production of similar rib die forgings to solve the problem of low-multiple flow in the die forgings. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of the structure of the U-shaped closed rib high rib die forging in the embodiment;

[0015] Figure 2 It is the high rib die forging of the middle-shaped closed rib in the embodiment;

[0016] Figure 3 This is a low-power microstructure inspection image of a die forging with a perforation defect. The arrow represents the perforation defect.

[0017] Figure 4 This is a low-power microstructure inspection diagram of the die forging metal obtained in the embodiment. There is no flow defect at the arrow point. DETAILED DESCRIPTION

[0018] Specific implementation method 1: In this implementation method, a method for preparing a U-shaped closed rib die forging for an aircraft is carried out according to the following steps:

[0019] 1. According to the mass percentage of the elements: Cu is 1.8% to 2.6%; Mg is 0.4% to 0.8%; Si is 0.7% to 1.2%; Fe is ≤0.7%; Mn is 0.4% to 0.8%; Ni is ≤0.1%, Zn is ≤0.3%, Ti is ≤0.15% and the balance is Al to prepare an aluminum alloy round ingot, and then perform homogenization annealing;

[0020] 2. Extruding the aluminum alloy ingot after homogenization annealing to obtain a long plate-shaped blank with a specification of 35 mm×310 mm;

[0021] 3. The long plate-shaped blank is subjected to low-power and fracture microstructure inspection. After the inspection is qualified, it is sawed, forged and stretched, and then placed in a mold for the first die forging. The opening forging temperature is 440℃~460℃, and the mold temperature is 420℃ to obtain die forging A;

[0022] Fourth, the die forging A obtained in step 3 is repaired with a milling machine to repair the high ribs on the edge, and then the edges and corners are polished with a grinder, and a hole with a diameter of 60 to 80 mm is drilled in the center;

[0023] 5. The die forgings processed in step 4 are heated, the start forging temperature is controlled to be 440° C. to 460° C., the final forging temperature is controlled to be 410° C. to 430° C., and after cleaning, they are die forged for the second time to obtain die forgings B;

[0024] 6. etching and repairing the die forging B obtained in step 5 to obtain an etched die forging;

[0025] 7. After the die forgings have been etched and washed, they are quenched and then subjected to aging treatment to complete the production of the die forgings.

[0026] Specific embodiment 2: This embodiment is different from specific embodiment 1 in that the size of the aluminum alloy ingot in step 1 is Φ350 mm to Φ410 mm. Other aspects are the same as those of specific embodiment 1.

[0027] Specific implementation method 3: This implementation method is different from specific implementation method 1 or 2 in that the milling surface in step 3 is: in step 2, the ingot is first heated to 480°C during extrusion, the ingot temperature is 430-450°C when placed in the extrusion cylinder, the extrusion cylinder temperature is 450°C, the extrusion ratio is 11.5-12.7, and the extrusion speed is 1.5 m / s. The rest is the same as specific implementation method 1 or 2.

[0028] Specific embodiment 4: This embodiment is different from specific embodiments 1 to 3 in that the temperature of the long plate-shaped blank in step 2 is 430° C. The rest is the same as specific embodiments 1 to 3.

[0029] Specific implementation method 5: This implementation method is different from specific implementation methods 1 to 4 in that: in step 3, the long plate-shaped blank is sawed into blanks of 35 mm×310 mm×160 mm. The rest is the same as specific implementation methods 1 to 4.

[0030] Specific implementation method 6: This implementation method is different from specific implementation methods 1 to 5 in that: in step 3, the final forging temperature of the die forging A is 410°C to 430°C, and the underpressure is controlled to be +2mm to +4mm. The rest is the same as specific implementation methods 1 to 5.

[0031] Specific implementation method 7: This implementation method is different from specific implementation methods 1 to 6 in that the molding speed in step 3 is 3 mm / s. The rest is the same as specific implementation methods 1 to 6.

[0032] Specific implementation eight: This implementation differs from specific implementations one to seven in that: in step five, the underpressure is controlled to be +1 mm to +2 mm during the second die forging. The rest is the same as specific implementations one to seven.

[0033] Specific embodiment 9: This embodiment is different from specific embodiments 1 to 8 in that: Step 6 of the etching treatment is to firstly perform etching and degreasing in an alkaline bath solution with a mass concentration of 20% to 30% NaOH at a temperature of 50°C to 60°C for 15 minutes, then wash off the alkaline solution, and then perform etching and degreasing in an alkaline bath solution with a mass concentration of 30% HNO 3 The die forgings are neutralized and washed in an acid tank for 10 minutes, the acid solution is washed off, and finally the die forgings are washed in a hot water tank with a water temperature of 40 to 50° C. The rest is the same as the specific embodiments 1 to 8.

[0034] Specific embodiment 10: This embodiment differs from specific embodiments 1 to 9 in that the quenching temperature in step 7 is 510°C to 516°C, the aging temperature is 153°C to 160°C, and the total heating time is 8 to 14 hours. The rest is the same as specific embodiments 1 to 9.

[0035] The content of the present invention is not limited to the content of the above-mentioned embodiments. The combination of one or several specific embodiments can also achieve the purpose of the invention.

[0036] The present application is described in detail below with reference to specific embodiments:

[0037] Example 1

[0038] A method for preparing a U-shaped closed rib die forging for an aircraft is carried out in the following steps:

[0039] 1. According to the mass percentage of the elements: Cu is 1.8% to 2.6%; Mg is 0.4% to 0.8%; Si is 0.7% to 1.2%; Fe is ≤0.7%; Mn is 0.4% to 0.8%; Ni is ≤0.1%, Zn is ≤0.3%, Ti is ≤0.15% and the balance is Al to prepare an aluminum alloy round ingot, and then perform homogenization annealing;

[0040] 2. Heat the aluminum alloy ingot after homogenization annealing to 480°C. When putting it into the extrusion cylinder, the ingot temperature is 430-450°C, the extrusion cylinder temperature is 450°C, the extrusion ratio is 11.5, the extrusion speed is 1.5 m / s, and the aluminum alloy strip blank with a specification of 35×310 is obtained; ensure that the temperature of the extruded strip is 430°C.

[0041] 3. The strip blank extruded in step 2 is subjected to low-magnification and fracture structure inspection, and heating forging can be carried out only after the inspection is qualified;

[0042] Fourth, cut the strip blank obtained in step 3 into trapezoidal blanks according to the drawing, and then heat it on a 3000-ton vertical hydraulic press to forge and lengthen it according to the drawing.

[0043] 5. Heat the blank obtained in step 4, control the start forging temperature to 440°C-460°C, the mold temperature to 420°C, place the blank in the mold for the first die forging to obtain die forging A, ensure that the final forging temperature of the die forging is 410°C-430°C, and control the underpressure to +2mm-+4mm.

[0044] 6. For the die forging A obtained in step 5, use a milling machine to repair the high ribs on the edge, grind the edges and corners with a grinder, and drill a hole with a diameter of 80 mm at the position shown in the figure (such as Figure 2 shown).

[0045] 7. Heat the die forging obtained in step 6, control the start forging temperature to 440°C to 460°C, and the final forging temperature to 410°C to 430°C. Place the cleaned pre-forging in a die for a second die forging to obtain die forging B; control the underpressure to +1mm to +2mm.

[0046] 8. The die forging B obtained in step 7 is subjected to etching and repairing treatment to obtain a clean die forging after etching;

[0047] 9. After quenching the die forging obtained in step 8, an aging treatment is performed, wherein the quenching temperature is 510°C to 516°C, the quenching holding time is 90 minutes (metal insulation), the temperature of the water used for quenching is 30°C to 50°C; the aging temperature is 153°C to 160°C (metal temperature), and the total heating time is 8 to 14 hours to complete the production of the die forging (such as Figure 1 shown).

[0048] 10. The microstructure and performance of the die forgings obtained in step 9 were tested. The tensile test results are shown in Table 1.

[0049] 11. The die forgings obtained in step 10 are hardened to 100% and then packaged and delivered.

[0050] Table 1

[0051]

[0052] When applying lubricating oil to forgings during die forging in step 5 and step 7, apply more oil in the middle and use a brush to shake the oil into the cavities on both sides. Do not apply oil to the material. Lubrication and pressing must be performed twice during final pressing, and then the car must be lifted and deflated before pressing again to ensure molding. The lubricating oil is a mixture of graphite and spindle oil in proportion, and a two-level 5000-ton pressure is used during pressing. The etching treatment described in step 8 is to first etch and degrease in an alkaline bath with a temperature of 50°C to 60°C and a mass concentration of 20% to 30% NaOH for 15 minutes, then wash the alkaline solution, and then in a mass concentration of 30% HNO 3 Neutralize and wash in the acid tank for 10 minutes, wash off the acid, and finally rinse the forgings in a hot water tank with a water temperature of 40-50℃.

[0053] The metal macrostructure inspection and comparative analysis of the U-shaped closed rib die forging obtained in this embodiment are carried out. Figure 3 and 4 As shown, it can be known that the die forging of this embodiment does not have low-magnification structure flow defects, thereby improving the bearing capacity, cracking resistance and toughness of the die forging, and increasing the service life of the die forging.

Claims

1. A method for preparing a U-shaped closed rib die forging for aircraft, characterized in that The method proceeds as follows:

1. According to the mass percentage of the elements: Cu is 1.8% to 2.6%; Mg is 0.4% to 0.8%; Si is 0.7% to 1.2%; Fe is ≤0.7%; Mn is 0.4% to 0.8%; Ni is ≤0.1%, Zn is ≤0.3%, Ti is ≤0.15% and the balance is Al to prepare an aluminum alloy round ingot, and then perform homogenization annealing; 2. Extruding the aluminum alloy ingot after homogenization annealing to obtain a long plate-shaped blank with a specification of 35 mm×310 mm; 3. The long plate-shaped blank is subjected to low-power and fracture microstructure inspection. After the inspection is qualified, it is sawed, forged and stretched, and then placed in a mold for the first die forging. The opening forging temperature is 440℃~460℃, and the mold temperature is 420℃ to obtain die forging A; Fourth, the die forging A obtained in step 3 is repaired with a milling machine to repair the high ribs on the edge, and then the edges and corners are polished with a grinder, and a hole with a diameter of 60 to 80 mm is drilled in the center; 5. The die forgings processed in step 4 are heated, the start forging temperature is controlled to be 440° C. to 460° C., the final forging temperature is controlled to be 410° C. to 430° C., and after cleaning, they are die forged for the second time to obtain die forgings B; 6. etching and repairing the die forging B obtained in step 5 to obtain an etched die forging; 7. After the die forgings have been etched and washed, they are quenched and then subjected to aging treatment to complete the production of the die forgings.

2. The method for preparing a U-shaped closed rib die forging for aircraft according to claim 1, characterized in that: The size of the aluminum alloy ingot in step 1 is Φ350mm~Φ410mm.

3. The method for preparing a U-shaped closed rib die forging for aircraft according to claim 1, characterized in that: Step 2: During extrusion, the ingot is first heated to 480°C. When placed in the extrusion barrel, the ingot temperature is 430-450°C, the extrusion barrel temperature is 450°C, the extrusion ratio is 11.5-12.7, and the extrusion speed is 1.5 m / s.

4. The method for preparing a U-shaped closed rib die forging for aircraft according to claim 1, characterized in that: Step 2: The temperature of the long plate-shaped blank extruded is 430°C.

5. The method for preparing a U-shaped closed rib die forging for aircraft according to claim 1, characterized in that: Step 3: Saw the long strip of plate-like blank into blanks of 35mm×310mm×160mm.

6. The method for preparing a U-shaped closed rib die forging for aircraft according to claim 1, characterized in that: Step 3: The final forging temperature of die forging A is 410℃~430℃, and the underpressure is controlled to be +2mm~+4mm.

7. The method for preparing a U-shaped closed rib die forging for aircraft according to claim 1, characterized in that: The molding speed in step three is 3 mm / S.

8. The method for preparing a U-shaped closed rib die forging for aircraft according to claim 1, characterized in that: Step 5: During the second die forging, control the underpressure to +1mm~+2mm.

9. The method for preparing a U-shaped closed rib die forging for aircraft according to claim 1, characterized in that: Step six: etching and degreasing is first performed in an alkaline bath with a mass concentration of 20% to 30% NaOH at a temperature of 50°C to 60°C for 15 minutes, then the alkaline solution is washed off, and then neutralized and washed in an acid bath with a mass concentration of 30% HNO3 for 10 minutes, the acid solution is washed off, and finally the die forgings are rinsed in a hot water bath with a water temperature of 40 to 50°C.

10. The method for preparing a U-shaped closed rib die forging for aircraft according to claim 1, characterized in that: In step seven, the quenching temperature is 510° C. to 516° C., the aging temperature is 153° C. to 160° C., and the total heating time is 8 to 14 hours.

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