Manufacturing and performance verification method for injection-molded aluminum alloy forgings for helicopters

Abstract

The invention provides a manufacturing and performance verification method of a spray-formed aluminum alloy forge piece for a helicopter, and the method comprises the following steps: carrying out spray forming on uniformly mixed metal powder to obtain a spray-formed aluminum alloy ingot blank; carrying out extrusion hot processing on the spray-formed aluminum alloy ingot blank; forging the ingot blank subjected to extrusion hot processing; the forged forge piece is subjected to heat treatment; and carrying out performance verification on the forged piece subjected to heat treatment. The spray-formed aluminum alloy forge piece manufactured based on the method can meet the weight reduction design requirements of typical bearing frames and other parts of helicopters, structural weight reduction is achieved, and the development requirements of ultra-light structures and high specific strength are met.

Description

Technical Field

[0001] This invention belongs to the field of helicopter technology, and in particular relates to a method for manufacturing and verifying the performance of spray-formed aluminum alloy forgings for helicopters. Background Technology

[0002] With the development of the aviation industry and the acceleration of the lightweighting process of large aviation equipment, aluminum alloys, due to their advantages such as high specific strength and good machinability, will become the main material for aviation forgings.

[0003] Currently, aluminum alloy materials are often prepared by casting. The process is as follows: a casting mold is designed and manufactured, then the various metal powders are mixed evenly, the evenly mixed metal powder is placed in a melting furnace and heated to a high-temperature liquid state, then the high-temperature liquid state liquid metal is poured into the casting mold, and after the liquid metal solidifies in the casting mold, it is taken out to obtain the final casting.

[0004] However, the new generation of high-performance aluminum alloy materials has a high alloy content and large differences in the density of alloy elements. When using aluminum alloy castings made by traditional casting methods to prepare high-performance aluminum alloy forgings, it is difficult to solve the problem of compositional segregation in large ingots, and the stability of performance is difficult to control. Summary of the Invention

[0005] To address the challenges of compositional segregation in large ingots and the difficulty in controlling performance stability when using traditional casting methods to prepare high-performance aluminum alloy forgings, this invention provides a method for manufacturing and verifying the performance of jet-formed aluminum alloy forgings for helicopters. The technical solution is as follows: A method for manufacturing and verifying the performance of jet-formed aluminum alloy forgings for helicopters, the method comprising: The uniformly mixed metal powder is sprayed to form a spray-formed aluminum alloy ingot. Extrusion hot processing of spray-formed aluminum alloy ingots; Forging of the extruded hot-processed billet; The forgings are then heat-treated. The performance of the heat-treated forgings was verified.

[0006] Optionally, the spray forming process is as follows: 99.80% aluminum ingot (Al), 99.95% cathode copper (Cu), 99.99% zinc ingot, 99.80% primary magnesium ingot, and aluminum-zirconium alloy (AlZr5) are mixed evenly. The spray forming equipment is inspected to ensure it is functioning properly. The spray forming equipment is then started for spray forming. The evenly mixed metal powder is heated using the spray forming equipment to obtain molten metal droplets. High-pressure inert gas is introduced to the nozzle through the initiation pipe in the spray forming equipment. Simultaneously, the molten metal droplets flow to the nozzle in the spray forming equipment. At the nozzle in the spray forming equipment, the high-pressure inert gas sprays the molten metal droplets onto the deposition platform in the spray forming equipment. As the molten metal droplets gradually accumulate in the deposition platform in the spray forming equipment, a spray-formed aluminum alloy ingot blank is finally formed.

[0007] Optionally, when spraying uniformly mixed metal powder, the gas pressure in the spray chamber is 5-10 MPa, the temperature in the spray chamber is 260-300℃, and the deposition frequency is 2-8 Hz. By controlling the above parameters, aluminum alloy ingots with uniform chemical composition and fine and uniform microstructure can be prepared.

[0008] Optionally, the extrusion hot processing specifically includes: Heating the spray-formed aluminum alloy ingot; Preheat the extrusion die; The spray-formed aluminum alloy ingot is upset and compacted. When the compaction reaches the preset pressure, the pressure is held. After depressurization, the preset pressure is used to hold the pressure. The depressurization and holding process is repeated multiple times. Heat preservation heating of the billet after upsetting and compaction; The extrusion die is heated; The upsetting and compacted billet is extruded using an extrusion die. During extrusion, the billet is compacted until it fills the entire die cavity. After it is filled, the extrusion is paused, and then the extrusion is resumed.

[0009] Optionally, during extrusion hot processing, the first heating temperature for the spray-formed aluminum alloy ingot is 350-420℃, held for 24-36 hours; the first preheating temperature for the extrusion die is 280-300℃, held for 12-18 hours; the upsetting and compaction speed for the spray-formed aluminum alloy ingot is 1.5-3mm / s; when compacted to 30,000 tons of pressure, the pressure is held for 1 minute; after depressurization, the pressure is held at 30,000 tons for 1 minute; this process is repeated 3 times. The second heating temperature for the upset and compacted ingot is 350-420℃, held for 8-12 hours; the second heating temperature for the extrusion die is 280-300℃, held for 12-18 hours; when extruding the upset and compacted ingot using the extrusion die, the main pusher extrusion speed is 2-4mm / s; extrusion stops when the upper and lower dies are in contact.

[0010] Optionally, the forging process is as follows: The first step is to perform free forging of the spray-formed aluminum alloy billet after extrusion and hot processing. First, heat the spray-formed aluminum alloy billet after extrusion and hot processing, and then forge the heated aluminum alloy billet by pressing it down through a forging press. The second step is to perform two-stage free forging on the spray-formed aluminum alloy ingot after one-stage free forging. First, the spray-formed aluminum alloy ingot after one-stage free forging is heated, and then the heated aluminum alloy ingot is pressed down by a forging press for forging. The third step is to perform die forging on the spray-formed aluminum alloy ingot after two-stage free forging.

[0011] Optionally, the heating temperature for the spray-formed aluminum alloy ingot after extrusion hot working is 350-420℃, and the reduction amount of the heated aluminum alloy ingot billet is 100mm when it is pressed down by the forging press. The heating temperature for the spray-formed aluminum alloy ingot after one-fire free forging is 350-420℃, and the reduction of the heated aluminum alloy ingot by pressing it down through the forging press is 50mm. The heating temperature for die forging of the spray-formed aluminum alloy ingot after two-stage free forging is 350-400℃, and the die temperature for die forging is 300-350℃. The die-forged part is then placed in the die for air cooling.

[0012] Optionally, the heat treatment process is as follows: The forgings after die forging are subjected to heat treatment, which is divided into solution treatment and quenching. During solution treatment, the forgings are kept at a constant temperature, and during quenching, the forgings after solution treatment are immersed in water to cool.

[0013] Optionally, when solution treating the forged parts after die forging, first hold them at 400-420℃ for 5-8 hours, and then hold them at 420-450℃ for 10-15 hours. When quenching solution-treated forgings, immerse the solution-treated forgings in water at 50°C and keep them in the water at 50°C for 60 minutes before removing them.

[0014] Optionally, when verifying the performance of heat-treated forgings, the heat-treated forgings may be tested for chemical composition, tensile properties, fracture toughness, smooth fatigue limit, notched fatigue limit, exfoliation corrosion resistance, stress corrosion resistance, and low-magnification microstructure.

[0015] The beneficial effects of this invention are at least as follows: Based on the requirements of helicopters for using sprayed aluminum alloy materials, this invention provides a method for manufacturing and verifying the performance of sprayed aluminum alloy forgings for helicopters. The sprayed aluminum alloy forgings manufactured based on this method can meet the weight reduction design requirements of typical load-bearing frames and other parts of helicopters, replace the existing 7050-T7451 forgings, achieve structural weight reduction, and meet the development needs of ultra-lightweight structures and high specific strength of models. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the blank preparation process for the present invention; Figure 2 This is a schematic diagram of the final forging process of the present invention; Figure 3 This is a flowchart of the method of the present invention. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] The features and illustrative embodiments of various aspects of the present invention will now be described in detail. Numerous specific details are set forth in the following detailed description to provide a thorough understanding of the invention. However, it will be apparent to those skilled in the art that the invention may be practiced without requiring some of these specific details. The following description of embodiments is merely intended to provide a better understanding of the invention by illustrating examples of the invention. The invention is by no means limited to any specific setups and methods set forth below, but covers any improvements, substitutions, and modifications to structures, methods, and devices without departing from the spirit of the invention. Well-known structures and techniques are not shown in the drawings and the following description to avoid unnecessarily obscuring the invention.

[0019] It should be noted that, unless otherwise specified, the embodiments of the present invention and the features thereof can be combined with each other, and the various embodiments can be referenced and cited from each other.

[0020] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0021] Spray forming can directly produce large-sized blanks with rapid solidification characteristics from liquid metal through minimal processes, effectively solving the problems of traditional processes and achieving a combination of high strength, high toughness, and high fatigue performance in aluminum alloys. This invention uses a 600MPa-grade Al-Zn-Mg-Cu ultra-high-strength aluminum alloy manufactured through spray forming to replace existing 500MPa-grade 7050-T7451 aluminum alloy parts, achieving a weight reduction of over 10%.

[0022] 7A55 spray-formed aluminum alloy is an Al-Zn-Mg-Cu aluminum alloy. Compared with the traditional 7050 aluminum alloy, its strength is increased by 20%. At the same time, it also has high fracture toughness and resistance to fatigue crack propagation.

[0023] Based on the urgent need for a new type of ultra-high strength aluminum alloy, 7A55, in order to reduce the weight of typical load-bearing components such as the frame of a helicopter, this invention carries out the manufacturing and performance verification of 7A55 aluminum alloy forgings to replace the existing 7050-T7451 forgings, thereby achieving structural weight reduction, meeting the development requirements of ultra-lightweight structures and high specific strength of models, and ensuring the achievement of technical and tactical indicators.

[0024] See Figure 1 , Figure 2 and Figure 3 This invention provides a method for manufacturing and verifying the performance of jet-formed aluminum alloy forgings for helicopters, comprising the following steps: The uniformly mixed metal powder is sprayed to form a spray-formed aluminum alloy ingot. Extrusion hot processing of spray-formed aluminum alloy ingots; Forging of the extruded hot-processed billet; The forgings are then heat-treated. The performance of the heat-treated forgings was verified.

[0025] In one embodiment, the spray forming process is as follows: Aluminum ingot (Al 99.80%), cathode copper (Cu 99.95%), zinc ingot (99.99%), primary magnesium ingot (99.80%), and aluminum-zirconium alloy (AlZr5) are mixed uniformly. Then, a pre-spray forming equipment inspection procedure is performed. Spray forming is then initiated, using the spray forming equipment to disperse the molten raw materials into uniform droplets. Simultaneously, the movement of the deposition platform is controlled to ensure a constant distance between the droplets and the deposition platform, thereby ensuring the stable production of uniform spray-formed aluminum alloy ingots. The spray chamber gas pressure is set to 5 MPa, the spray chamber temperature to 260°C, and the deposition frequency to 2 Hz. This method produces aluminum alloy ingots with uniform chemical composition and fine, uniform microstructure.

[0026] In one embodiment, the extrusion hot processing process is as follows: First, the spray-formed aluminum alloy ingot is heated to 400°C and held at that temperature for 24 hours; the die is preheated to 280°C and held for 12 hours; then, upsetting and compaction are performed at a compaction speed of 1.5 mm / s, and the compaction is carried out at a pressure of 30,000 tons for 1 minute, after which the pressure is released and held at 30,000 tons for 1 minute, and the pressure release and holding are repeated 3 times; the ingot is heated and kept at 400°C for 8 hours; the die is heated and preheated to 280°C for 12 hours; then extrusion begins, with the main pusher extrusion speed at 2 mm / s. During extrusion, the compaction is first carried out until the entire die cavity is filled, and after filling, the process is paused for 2 minutes, and then extrusion is carried out again until the residual pressure is 50 mm and then the extrusion is stopped.

[0027] In one embodiment, the forging process is as follows: Free forging 1 heats the billet to 400°C and forges it with a reduction of 100mm; Free forging 2 heats the billet to 400°C and forges it with a reduction of 50mm; Die forging heats the billet to 400°C, the die temperature is 350°C, the cooling method is air cooling, the transfer time is 3min, and the under-pressure is 50mm.

[0028] In one embodiment, the heat treatment process is as follows: solution treatment, holding at 420°C for 5 hours, holding at 450°C for 10 hours, quenching water temperature of 50°C, quenching water immersion time of 10 seconds, water immersion method is side-standing water immersion, and water cooling time of 60 minutes. In one embodiment, the performance verification method is as follows: the performance verification is completed by conducting tests on chemical composition, tensile properties, fracture toughness, smooth fatigue limit, notch fatigue limit, exfoliation corrosion resistance, stress corrosion resistance, and low-magnification microstructure. If each performance meets the index requirements, the forging is deemed qualified.

[0029] The key points of this invention are as follows: 1) This invention innovatively designs a method for manufacturing and verifying the performance of spray-formed aluminum alloy forgings for helicopters, which mainly includes the following steps: spray forming, extrusion hot working, forging, heat treatment, and performance verification.

[0030] 2) In this invention, “aluminum ingot Al99.80%, cathode copper Cu99.95%, zinc ingot 99.99%, primary magnesium ingot 99.80%, and aluminum-zirconium alloy AlZr5” are mixed evenly, and the spray chamber gas pressure is set to 5MPa, the spray chamber temperature to 260℃, and the deposition frequency to 2Hz for spray forming.

[0031] 3) In this invention, the spray-formed aluminum alloy ingot is first heated to 400℃ and held at that temperature for 24 hours; the mold is preheated to 280℃ and held for 12 hours; then upsetting and compaction are performed at a compaction speed of 1.5 mm / s, and the compaction is carried out at a pressure of 30,000 tons for 1 minute. After depressurization, the pressure is maintained at 30,000 tons for 1 minute, and the depressurization and pressure maintenance are repeated 3 times; the ingot is heated and kept at 400℃ for 8 hours; the mold is heated and preheated to 280℃ for 12 hours; then extrusion begins, with the main pusher extrusion speed at 2 mm / s. During extrusion, the ingot is first compacted until the entire mold cavity is filled, and then paused for 2 minutes before extrusion is resumed until the remaining pressure is 50 mm.

[0032] 4) In this invention, the free forging 1 heats the billet to a temperature of 400°C for forging, with a reduction of 100mm; the free forging 2 heats the billet to a temperature of 400°C for forging, with a reduction of 50mm; the die forging heating temperature is 400°C, the die temperature is 350°C, the cooling method is air cooling, the transfer time is 3min, and the under-pressure is 50mm.

[0033] 5) In this invention, the heat treatment method is as follows: solution treatment, holding at 420℃ for 5 hours, holding at 450℃ for 10 hours, quenching water temperature of 50℃, quenching water immersion time of 10 seconds, water immersion method is side-mounted water immersion, and water cooling time of 60 minutes.

[0034] The above description merely illustrates embodiments of the present invention and is quite specific and detailed; however, it should not be construed as limiting the scope of the patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the scope of protection of the present invention. Furthermore, any parts of the present invention not described in detail are conventional techniques.

Claims

1. A method for manufacturing and verifying the performance of jet-formed aluminum alloy forgings for helicopters, characterized in that, The method includes: The uniformly mixed metal powder is sprayed to form a spray-formed aluminum alloy ingot. Extrusion hot processing of spray-formed aluminum alloy ingots; Forging of the extruded hot-processed billet; The forgings are then heat-treated. The performance of the heat-treated forgings was verified.

2. The method according to claim 1, characterized in that, The spray forming process is as follows: 99.80% aluminum ingot (Al), 99.95% cathode copper (Cu), 99.99% zinc ingot, 99.80% primary magnesium ingot, and aluminum-zirconium alloy (AlZr5) are mixed evenly. The spray forming equipment is inspected to ensure it is functioning properly. The spray forming equipment is then started to perform spray forming. The evenly mixed metal powder is heated using the spray forming equipment to obtain molten metal droplets. High-pressure inert gas is introduced to the nozzle through the initiation pipe in the spray forming equipment. At the same time, the molten metal droplets flow to the nozzle in the spray forming equipment. The high-pressure inert gas at the nozzle sprays the molten metal droplets onto the deposition platform in the spray forming equipment. As the molten metal droplets gradually accumulate in the deposition platform in the spray forming equipment, a spray-formed aluminum alloy ingot blank is finally formed.

3. The method according to claim 2, characterized in that, When spraying uniformly mixed metal powder, the gas pressure in the spray chamber is 5~10MPa, the temperature in the spray chamber is 260~300℃, and the deposition frequency is 2-8Hz.

4. The method according to claim 3, characterized in that, The specific process of extrusion hot processing is as follows: Heating the spray-formed aluminum alloy ingot; Preheat the extrusion die; The spray-formed aluminum alloy ingot is upset and compacted. When the compaction reaches the preset pressure, the pressure is held. After depressurization, the preset pressure is used to hold the pressure. The depressurization and holding process is repeated multiple times. Heat preservation heating of the billet after upsetting and compaction; The extrusion die is heated; The upsetting and compacted billet is extruded using an extrusion die. During extrusion, the billet is compacted until it fills the entire die cavity. After it is filled, the extrusion is paused, and then the extrusion is resumed.

5. The method according to claim 4, characterized in that, During extrusion hot processing, the first heating temperature for the spray-formed aluminum alloy ingot is 350-420℃, and the holding temperature is 24-36 hours. The first preheating temperature for the extrusion die is 280-300℃, and the holding temperature is 12-18 hours. The upsetting and compaction speed of the spray-formed aluminum alloy ingot is 1.5-3mm / s. When compaction reaches 30,000 tons of pressure, the pressure is held for 1 minute. After depressurization, the pressure is held at 30,000 tons for 1 minute. This process of depressurization and holding is repeated 3 times. The second heating temperature for the upset and compacted ingot is 350-420℃, and the holding temperature is 8-12 hours. The second heating temperature for the extrusion die is 280-300℃, and the holding temperature is 12-18 hours. When extruding the upset and compacted ingot with the extrusion die, the main pusher extrusion speed is 2-4mm / s. Extrusion is stopped when the upper and lower dies are in contact.

6. The method according to claim 5, characterized in that, The forging process is as follows: The first step is to perform free forging of the spray-formed aluminum alloy billet after extrusion and hot processing. First, heat the spray-formed aluminum alloy billet after extrusion and hot processing, and then forge the heated aluminum alloy billet by pressing it down through a forging press. The second step is to perform two-stage free forging on the spray-formed aluminum alloy ingot after one-stage free forging. First, the spray-formed aluminum alloy ingot after one-stage free forging is heated, and then the heated aluminum alloy ingot is pressed down by a forging press for forging. The third step is to perform die forging on the spray-formed aluminum alloy ingot after two-stage free forging.

7. The method according to claim 6, characterized in that, The heating temperature for the spray-formed aluminum alloy ingot after extrusion hot working is 350-420℃, and the reduction amount of the heated aluminum alloy ingot billet is 100mm when it is pressed down by the forging press. The heating temperature for the spray-formed aluminum alloy ingot after one-fire free forging is 350-420℃, and the reduction of the heated aluminum alloy ingot by pressing it down through the forging press is 50mm. The heating temperature for die forging of the spray-formed aluminum alloy ingot after two-stage free forging is 350-400℃, and the die temperature for die forging is 300-350℃. The die-forged part is then placed in the die for air cooling.

8. The method according to claim 7, characterized in that, The heat treatment process is as follows: The forgings after die forging are subjected to heat treatment, which is divided into solution treatment and quenching. During solution treatment, the forgings are kept at a constant temperature, and during quenching, the forgings after solution treatment are immersed in water to cool.

9. The method according to claim 8, characterized in that, When solution treating the die-forged parts, first hold them at 400-420℃ for 5-8 hours, and then hold them at 420-450℃ for 10-15 hours. When quenching solution-treated forgings, immerse the solution-treated forgings in water at 50°C and keep them in the water at 50°C for 60 minutes before removing them.

10. The method according to claim 1, characterized in that, When verifying the performance of heat-treated die forgings, the chemical composition, tensile properties, fracture toughness, smooth fatigue limit, notched fatigue limit, exfoliation corrosion resistance, stress corrosion resistance, and low-magnification microstructure of the heat-treated die forgings are tested.

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