Aluminum alloy multi-cavity profile extrusion production process

Abstract

The invention discloses an extrusion production process for an aluminum alloy multi-cavity profile. The extrusion production process comprises the following steps that S1, raw materials are prepared; s2, designing and manufacturing a mold; s3, pretreatment before extrusion; s4, extrusion forming; s5, cooling treatment; s6, straightening and finishing; s7, aging treatment; and S8, detecting and packaging. According to the invention, the friction is further reduced by adopting a special high-temperature lubricant and an ultrasonic vibration device in the pre-extrusion pretreatment, the precise control is realized by arranging real-time monitoring and feedback systems such as a laser range finder and an infrared thermometer in the extrusion forming process, and the cooling treatment is realized by automatically adjusting parameters by adding a corrosion inhibitor and arranging a sensor, so that the production efficiency is improved. The cooling quality of the profile is ensured; laser scanning and electrolytic polishing technologies are adopted for straightening and finishing, the straightening precision and the surface quality are improved, a circulating hot air system and a segmented aging mode are adopted for aging treatment, and the aging effect is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of profile extrusion production, and in particular to an aluminum alloy multi-cavity profile extrusion production process. Background Art

[0002] With the rapid development of industries such as aerospace, automobile manufacturing, and construction, aluminum alloy multi-cavity profiles have been widely used due to their advantages such as light weight, high strength, and corrosion resistance.

[0003] However, in the existing aluminum alloy multi-cavity profile extrusion production process, due to the complex structure of the profile and the presence of multiple cavities inside, the metal flow in each part is uneven, making it difficult to ensure the dimensional accuracy of the profile. Common problems include inconsistent wall thickness. The wall thickness deviation in some areas can reach more than ±0.15mm, seriously affecting the load-bearing capacity and assembly accuracy of the profile; the cavity deformation problem is also more prominent, resulting in the profile unable to meet the design requirements and increasing the scrap rate. The diversion holes of the mold mostly adopt fixed apertures and simple shapes, and cannot reasonably distribute the metal flow according to the volume ratio of each part of the profile, causing the metal flow in the mold to be disordered, which not only reduces the molding quality of the profile, but also leads to a generally low yield rate. Summary of the Invention

[0004] The purpose of the present invention is to solve the shortcomings of the prior art and to propose an aluminum alloy multi-cavity profile extrusion production process.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A production process for extruding aluminum alloy multi-cavity profiles, comprising the following steps:

[0007] S1. Raw material preparation: Select aluminum alloy ingots, conduct chemical composition testing and mechanical property testing, use gradient heating or homogenization annealing treatment, and add trace rare earth elements to the raw materials;

[0008] S2. Mold design and manufacturing: Design an extrusion mold with a special diverter hole structure. The diverter hole adopts a gradual aperture design or a variable angle design. A spiral guide groove is set on the inner wall of the diverter hole. The mold core adopts a mosaic structure or modular design. The mold surface is nitrided or sprayed with a nano-ceramic coating.

[0009] S3. Pretreatment before extrusion: clean the ingot surface, apply high-temperature lubricant, heat the extrusion barrel, and install an ultrasonic vibration device on the inner wall of the extrusion barrel;

[0010] S4, extrusion molding: put the ingot into the extrusion barrel, start the extruder, monitor the extrusion pressure and temperature in real time, adjust the extrusion speed and mold temperature, use a double-action extruder to apply reverse pressure, and set a laser rangefinder and infrared thermometer at the extruder outlet;

[0011] S5. Cooling treatment: adopt segmented cooling, liquid nitrogen spray combined with air cooling, air cooling combined with mist cooling or austempering cooling;

[0012] S6. Straightening and finishing: Use multi-roll straightening machine for straightening, use laser scanning technology to monitor deformation, and use electrolytic polishing or mechanical polishing for surface finishing;

[0013] S7, aging treatment: artificial aging or natural aging is carried out, a circulating hot air system is set in the aging furnace, and a staged aging method is adopted;

[0014] S8. Inspection and packaging: The profiles are inspected for dimensional accuracy, mechanical properties and surface quality, and are packaged and stored after passing the inspection.

[0015] Preferably, in said S1, the gradient heating is to first heat the ingot to 400-450°C at a rate of 15°C / min, keep it warm for 1-2 hours, then heat it to 480-520°C and keep it warm for 2-4 hours, the homogenization annealing temperature is 450-470°C, keep it warm for 4-6 hours, and the amount of rare earth elements added is 0.05-0.2%.

[0016] Preferably, in S2, the aperture of the feed end of the gradual diversion hole is 18-20 mm, the aperture of the discharge end is 10-12 mm, the angle between the feed end of the variable-angle diversion hole and the mold axis is 30°, the angle between the discharge end is 15°, the pitch of the spiral guide groove is 10-20 mm, and the depth is 0.5-1 mm. The key parts of the inlaid mold core are inlaid with carbide, and the modular mold core is connected to the mold body by positioning pins and bolts.

[0017] Preferably, the high-temperature lubricant is made by mixing nano-scale molybdenum disulfide and high-temperature resistant resin, the particle size of nano-scale molybdenum disulfide is 50-100nm, the frequency of the ultrasonic vibration device is 20-40kHz, and the opening time is 1-2 minutes.

[0018] Preferably, in S4, the extrusion speed is 3-5 mm / s, the extrusion pressure is controlled at 80-120 MPa, the mold temperature is controlled at 460-490° C., and the reverse pressure applied by the double-action extruder is 10-20% of the extrusion pressure.

[0019] Preferably, in S5, the first stage of strong wind cooling has a wind speed of 10-15m / s, which reduces the profile temperature to 300-350°C; the second stage of water mist cooling has a water mist particle diameter controlled at 5-10μm, which reduces the profile temperature to 200-250°C; the third stage of natural cooling to room temperature, when liquid nitrogen spray is combined with air cooling, the liquid nitrogen spray pressure is 0.5MPa, the droplet diameter is about 3μm, when air cooling is combined with mist cooling, the air cooling wind speed is 10-12m / s, and the diameter of the mist cooling water mist particles is 5-10μm; the isothermal quenching cooling is to place the profile in a quenching medium at 200-250°C and keep warm for 30-60 minutes.

[0020] Preferably, in S6, the multi-roll straightening machine controls the straightness of the profile to within 0.5 mm / m, the electrolytic polishing electrolyte adopts a mixed solution of phosphoric acid, sulfuric acid and chromic anhydride, and the mechanical polishing makes the surface finish of the profile reach Ra0.8-1.6 μm.

[0021] Preferably, in S7, the artificial aging temperature is 180-200°C for 6-8 hours, the natural aging is placed at room temperature for 72 hours, the circulating hot air flow rate is 5-10 m / s, and the staged aging is first performed at 180-190°C for 3-4 hours, and then the temperature is raised to 190-200°C for 3-4 hours.

[0022] The present invention has the following beneficial effects:

[0023] 1. By optimizing the mold design, adopting a gradual diversion hole structure and setting a spiral guide groove, and adopting a mosaic structure for the mold core, the uniform flow of metal during the extrusion process is ensured, the service life of the mold and the dimensional accuracy and molding quality of the profile are improved.

[0024] 2. The use of segmented heating and the addition of rare earth elements refines the grain structure and improves the performance of the aluminum alloy. The pre-extrusion pretreatment further reduces friction by using special high-temperature lubricants and ultrasonic vibration devices. During the extrusion molding process, precise control is achieved by setting up real-time monitoring and feedback systems such as laser rangefinders and infrared thermometers. The cooling treatment ensures the cooling quality of the profile by adding corrosion inhibitors and setting sensors to automatically adjust parameters. Laser scanning and electrolytic polishing technology are used for straightening and finishing to improve straightening accuracy and surface quality. A circulating hot air system and segmented aging method are used for aging treatment to enhance the aging effect.

[0025] 3. Through intelligent temperature-controlled molds and precise monitoring and feedback systems, the wall thickness deviation is controlled at ±0.05mm, the straightness error is reduced to 0.3mm / m, and the surface finish is improved to Ra0.8-1.2μm. This enables the produced profiles to meet the stringent requirements of high-end fields such as aerospace for component dimensional accuracy and surface quality. For example, in the manufacture of aircraft fuselage frames, high-precision profiles can reduce assembly errors and improve the stability and safety of the overall structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic diagram of the production steps of an aluminum alloy multi-cavity profile extrusion production process proposed by the present invention. DETAILED DESCRIPTION

[0027] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0028] Example 1: Extrusion process based on intelligent die control

[0029] Step 1. Raw material processing: Select 7075 aluminum alloy ingots. 7075 aluminum alloy is often used in aerospace, high-end equipment manufacturing and other fields due to its high strength, good toughness and fatigue resistance. Use a spectrometer to conduct strict chemical composition testing. The spectrometer generates characteristic spectra by exciting the sample to analyze the content of zinc, magnesium, copper and other elements in the alloy to ensure that the proportion of alloy elements meets the requirements of GB / T3190-2020 standards. Use gradient heating to place the ingot in a heating furnace with an intelligent temperature control system. First, heat it to 400°C at a rate of 15°C / min. The heating rate at this stage is moderate, which can avoid thermal stress caused by rapid temperature changes in the ingot. Keep it warm for 1.5 hours to make the internal structure of the ingot initially homogenized; then heat it to 510°C and keep it warm for 3 hours. During the long-term high-temperature heat preservation process, the coarse grains in the ingot gradually refine, the composition segregation is improved, and the uniformity of the structure is significantly improved. During the heating process, the temperature in the furnace is monitored in real time, and the temperature fluctuation range is controlled within ±5°C;

[0030] Step 2. Mold design and use: Design an intelligent temperature control mold. The mold body is made of H13 hot working die steel. The steel has good thermal stability, wear resistance and toughness. Micro temperature sensors are built into key parts of the mold (such as the diverter bridge and mold core). The temperature sensor uses a high-precision thermocouple sensor with a measurement accuracy of ±1°C. It can accurately monitor the temperature of various parts of the mold in real time. At the same time, a heating element is installed. The heating element adopts a resistance wire heating method. The PLC control system realizes real-time monitoring and precise adjustment of the mold temperature. The mold diverter hole adopts a variable angle design. The angle between the diverter hole at the feed end and the mold axis is 30°. The larger angle helps the metal to quickly enter the diverter hole and exit. The angle at the material end gradually decreases to 15°, guiding the metal to flow more smoothly into the forming cavity. This design conforms to the flow law of metal during the extrusion process, making the metal flow more uniform. Before extrusion, a dedicated mold preheating device is used to preheat the mold. The temperature is set to 470°C. During the preheating process, a staged heating method is adopted, first heating to 300°C and holding for 0.5 hours, and then heating to 470°C to avoid cracks in the mold due to rapid temperature changes. After preheating, a nano-ceramic coating is sprayed on the mold surface. The nano-ceramic coating adopts plasma spraying technology. The coating thickness is controlled at 0.1-0.2mm, reducing the surface roughness to Ra0.2μm, greatly reducing the metal flow resistance.

[0031] Step 3, extrusion process: the pretreated ingot is placed in the extrusion barrel, which is also equipped with a temperature control system, heated to 460 ° C and maintained at a constant temperature, and the extruder is started. The extruder is driven by a servo motor, which can accurately control the extrusion speed and start extrusion at a speed of 4 mm / s. During the extrusion process, the temperature sensor will feed back the real-time monitored mold temperature data to the PLC control system. When the local temperature of the mold is lower than 460 ° C, the PLC control system automatically starts the heating element to heat up. When the temperature is higher than 490 ° C, the cooling system is started to cool down. The cooling system adopts a circulating water cooling method and controls the cooling speed by adjusting the water flow. At the same time, the extrusion pressure is monitored in real time by a pressure sensor with an accuracy of ±0.5 MPa. The extrusion speed is adjusted by the servo motor to stabilize the pressure at 100-110 MPa. In addition, a data acquisition system is installed on the extruder to record the temperature, pressure, speed and other parameters during the extrusion process in real time, which is convenient for subsequent analysis and optimization of the process.

[0032] Step 4. Cooling and subsequent treatment: After the profile is extruded, it immediately enters the cooling system. The cooling system uses a combination of liquid nitrogen spray and air cooling. The liquid nitrogen spray device consists of a liquid nitrogen storage tank, a pressure regulator, and an atomizing nozzle. The liquid nitrogen spray pressure is 0.5MPa, and the droplet diameter is about 3μm. It can quickly take away the heat from the surface of the profile. The surface temperature of the profile is first quickly reduced to 150℃ by liquid nitrogen spray, and then air cooling is carried out. The air cooling device is equipped with multiple sets of fans with a wind speed of 12m / s, so that the profile temperature gradually drops to room temperature. After cooling The profiles are sent to the straightening machine for straightening treatment. The straightening machine adopts a multi-roller straightening method. The pressure and angle of the straightening rollers are automatically adjusted according to the deformation of the profile. After straightening, finishing is carried out. Finishing includes removing surface burrs, grinding and other processes to make the surface quality of the profile meet the requirements. Finally, artificial aging treatment is carried out. The profiles are placed in an aging furnace. The artificial aging temperature is set at 190℃ and the time is 7 hours. During the aging process, the temperature uniformity in the aging furnace is controlled within ±3℃. Through aging treatment, the strength and hardness of the profiles are significantly improved;

[0033] In this embodiment, the intelligent temperature-controlled mold effectively avoids profile deformation and surface defects caused by uneven mold temperature by real-time monitoring and precise adjustment of the mold temperature. Actual production verification shows that the wall thickness deviation of the profiles produced by this process can be controlled within ±0.05mm. Compared with traditional processes, the dimensional accuracy is improved by 40%-50%, which can meet the strict requirements of high-end fields such as aerospace for profile dimensional accuracy. The variable-angle diverter hole design and nano-ceramic coating significantly improve the flow state of the metal. Under the same production conditions, when extruding with this mold, the extrusion force is reduced by about 15%-20% compared with the traditional mold, reducing the stress on the mold, thereby reducing mold wear, extending the mold service life by more than 20%, and reducing the frequency of mold replacement and production costs.

[0034] Furthermore, the cooling method that combines liquid nitrogen spray with air cooling greatly improves the cooling speed. Rapid cooling significantly refines the grain structure of the profile. Metallographic analysis shows that the grain size is reduced by 30%-40% compared with the traditional cooling method. Grain refinement brings about improved mechanical properties. The tensile strength of the profile is increased by 10%-15%, and the yield strength is increased by 8%-12%, which improves the comprehensive performance of the profile. The entire production process realizes automated monitoring and control, reduces manual intervention, and reduces the impact of human factors on production. The production efficiency is increased by 30%-40% compared with the traditional process, and the scrap rate can be controlled below 3%, which is more than 50% lower than the traditional process, thereby improving the economic benefits of the enterprise.

[0035] Example 2: Dual-die alternating extrusion process

[0036] Step 1. Raw material preparation: Select 6061 aluminum alloy ingot. 6061 aluminum alloy has good comprehensive properties and is widely used in construction, automobile, shipbuilding and other industries. Perform homogenization annealing on the ingot and place it in an annealing furnace. Set the annealing temperature to 470°C and keep it warm for 4 hours. During the annealing process, control the temperature and time in the furnace to eliminate the residual stress inside the ingot and improve the microstructure and performance of the ingot. After annealing, cut the ingot into appropriate lengths. Use a high-precision circular saw to cut, and the cutting accuracy is controlled within ±1mm. The surface of the cut ingot is sandblasted with alumina sand particles with a particle size of 0.5-1mm and a sandblasting pressure of 0.3-0.5MPa to remove the oxide scale on the surface of the ingot and expose the fresh metal surface. Then apply a layer of graphite-based high-temperature lubricant on the surface of the ingot. The lubricant is sprayed with a spray thickness of 0.1-0.2mm to ensure that the surface of the ingot is evenly covered with lubricant to reduce the friction between the ingot and the mold.

[0037] Step 2: Mold configuration: prepare two sets of extrusion molds with the same structure but quickly replaceable mold cores. The mold body is made of high-quality mold steel, and the mold core adopts a modular design. According to the multi-cavity profiles of different specifications, mold cores of various specifications are designed. The mold core and the mold body are connected with positioning pins and bolts to facilitate quick replacement. The diversion hole and working belt of the mold are processed by electric spark machining technology. The electric spark machining adopts CNC electric spark machine tools with a processing accuracy of ±0.01mm to ensure the dimensional accuracy and surface quality of the metal flow channel. After the mold is manufactured, it is nitrided to improve the surface hardness and wear resistance of the mold. The thickness of the nitride layer is controlled at 0.1-0.2mm.

[0038] Step 3, extrusion process: Install the first set of molds on the extruder, and use special mold installation equipment to ensure that the mold is installed in the correct position. After installation, preheat the mold and set the preheating temperature to 460℃. Start the extruder and feed the ingot into the extrusion barrel. Extrude at a speed of 3.5mm / s. During the extrusion process, monitor the extrusion pressure and temperature in real time to ensure the stability of the extrusion process. After one extrusion is completed, start the mold quick change system immediately. The quick change system is hydraulically driven and can complete the mold replacement within 3 minutes. At the same time, quickly cool and clean the first set of molds. Cooling uses forced water cooling. Place the mold in the cooling water tank. The water temperature in the water tank is controlled at 20-25℃ to quickly drop the mold temperature to below 60℃. Clean the residual metal and lubricant on the mold surface. Cleaning uses a combination of high-pressure air blowing and special mold cleaning agents to ensure that the mold surface is clean for the next use. Two sets of molds are used alternately for continuous extrusion production;

[0039] Step 4. Subsequent processing: After the profile is extruded, it enters the cooling system for segmented water quenching cooling. The water temperature of the first section is set to 20°C and the cooling time is 30 seconds. Rapid cooling at this stage allows the profile surface to solidify rapidly and form a certain strength. The water temperature of the second section is set to 40°C and the cooling time is 20 seconds. Slow cooling reduces the thermal stress inside the profile. After cooling, the profile is sent to the straightening machine for straightening treatment. The straightening machine adopts a multi-roller straightening method. Through multiple straightening, the straightness of the profile meets the requirements. After straightening, artificial aging is performed. The profile is placed in an aging furnace with an aging temperature set to 185°C and a time of 6 hours to improve the strength and hardness of the profile. Finally, the surface is anodized. Anodizing adopts sulfuric acid anodizing process. The thickness of the oxide film is controlled at 8-12μm to improve the corrosion resistance and aesthetics of the profile.

[0040] In this embodiment, the dual-die alternating extrusion method significantly reduces die replacement and cooling waiting time. With traditional single-die extrusion, each die replacement and cooling takes approximately 30-40 minutes. However, dual-die alternating extrusion enables continuous production, increasing production efficiency by 30%-40%. This method is particularly suitable for large-scale continuous production and can meet the market's high demand for aluminum alloy multi-cavity profiles. The modular core design improves the mold's versatility. A single mold body can be paired with a variety of cores to meet the production needs of profiles of varying specifications. Compared to traditional molds, mold manufacturing costs are reduced by 20%-30%. Core replacement is also convenient and quick, reducing production downtime due to mold changes and further improving production efficiency.

[0041] Furthermore, high-precision EDM ensures the dimensional accuracy of the mold runner. After testing, the mold manufactured using this process has a dimensional error of the diversion hole and the working zone controlled within ±0.01mm, which makes the dimensional consistency of the profile better and the product qualification rate increased to more than 95%. Compared with the product qualification rate of traditional mold production, it has increased by 10%-15%, reducing scrap loss. The segmented water quenching cooling can effectively control the cooling rate and deformation of the profile. Through two stages of cooling at different temperatures, it not only ensures the quenching effect of the profile, but also reduces the internal cracks caused by too fast cooling. The profiles produced by this cooling method have uniform internal structure and stable mechanical properties. At the same time, the quenching hardness of the profile is improved, meeting the requirements of profile performance in different application scenarios.

[0042] Example 3: Ultrasonic-assisted extrusion process

[0043] Step 1, raw material pretreatment: select 5052 aluminum alloy ingot, 5052 aluminum alloy has good corrosion resistance and weldability, and is often used to manufacture containers, pipes, etc., and perform homogenization treatment on the ingot. Place the ingot in a homogenization treatment furnace, set the treatment temperature to 450℃, and keep it warm for 6 hours to eliminate the component segregation and residual stress inside the ingot. After homogenization treatment, process spiral shallow grooves on the surface of the ingot using CNC processing equipment. The groove depth is 0.3mm and the pitch is 5mm. Immerse the ingot in an aqueous solution containing 0.1% ultrasonic dispersant. The dispersant adopts a special formula that can better penetrate into the shallow groove under the action of ultrasonic waves. The ingot is treated with ultrasonic waves with a frequency of 25kHz for 15 minutes. The ultrasonic treatment equipment uses an ultrasonic cleaning machine. Through the cavitation effect of ultrasonic waves, the dispersant fully penetrates into the shallow groove, further improving the lubrication performance of the ingot surface and reducing the friction between the ingot and the mold.

[0044] Step 2. Mold and equipment configuration: An ultrasonic vibration system is set in the extrusion barrel and the mold. The ultrasonic vibration system in the extrusion barrel consists of an ultrasonic generator, a transducer and a vibration rod, and the vibration frequency is 20kHz. The ultrasonic vibration system of the mold also consists of an ultrasonic generator, a transducer and a vibration rod, and the vibration frequency is 22kHz. The mold adopts a split structure, which is divided into an upper mold and a lower mold, which are connected by positioning pins and bolts for easy installation and disassembly. The mold core is made of tungsten carbide, which has high hardness, high wear resistance and good thermal stability, and can increase the service life of the mold. After the mold is manufactured, it is surface polished and the surface roughness is reduced to Ra0.4μm to reduce metal flow resistance.

[0045] Step 3, extrusion process: Place the pretreated ingot into the extrusion barrel, heat the extrusion barrel to 460℃ and maintain a constant temperature, start the extruder and ultrasonic vibration system, the extruder is driven by a variable frequency motor, which can accurately control the extrusion speed and extrude at a speed of 4.5mm / s. During the extrusion process, ultrasonic vibration can generate high-frequency mechanical vibration, reduce the friction between the metal and the mold, and promote the uniform flow of the metal. The extrusion pressure and temperature are monitored in real time. The pressure sensor accuracy is ±0.5MPa, and the temperature sensor accuracy is ±1℃. The extrusion parameters are optimized by adjusting the power of the ultrasonic wave. When the extrusion pressure is too high, the ultrasonic power is appropriately increased to reduce friction. When the mold temperature is too high, the cooling system is started to cool down. The cooling system uses air cooling to stabilize the extrusion pressure at 90-100MPa and the mold temperature is maintained at around 475℃. At the same time, during the extrusion process, a high-speed camera is used to observe the flow of the metal so that the process parameters can be adjusted in time.

[0046] Step 4, post-processing: After the profile is extruded, a cooling method combining air cooling and mist cooling is adopted. The air cooling device is equipped with multiple sets of fans with a wind speed of 10m / s. The profile is first cooled to 280℃ by air. At this stage, the surface temperature of the profile is quickly reduced, and then mist cooling is performed. The mist cooling device consists of a water tank, a water pump, and an atomizing nozzle. The diameter of the water mist particles is controlled at 5-10μm, which reduces the temperature of the profile to room temperature. After cooling, straightening is performed. The straightening machine adopts a hydraulic straightening method. The straightening pressure is accurately adjusted according to the deformation of the profile. After straightening, natural aging is performed. The profile is placed at room temperature for 72 hours to gradually stabilize the internal structure of the profile. Finally, mechanical polishing is performed. Polishing uses a sand belt polisher to make the surface finish of the profile reach Ra0.8μm.

[0047] In this embodiment, ultrasonic-assisted treatment significantly improves the lubrication performance of the ingot surface, and the cavitation effect of the ultrasonic wave enables the dispersant to fully penetrate into the shallow grooves on the surface of the ingot, forming a more effective lubricating layer, reducing the friction between the metal and the mold. In actual production, the extrusion force is reduced by 10%-15% compared with the traditional process, while improving the fluidity of the metal, effectively avoiding scratches and mold sticking on the profile surface, and improving the surface quality of the profile. Ultrasonic vibration promotes the dynamic recrystallization process inside the metal. During the extrusion process, the high-frequency vibration of the ultrasonic wave causes tiny stress and strain inside the metal, promotes the nucleation and growth of grains, and refines the grain structure. According to metallographic analysis, the grain size of the profile is reduced by 25%-35% compared with the traditional process, and the elongation of the profile is increased by 12%-18%. The plasticity is significantly improved, and it is more suitable for subsequent processing and use.

[0048] Furthermore, the split mold structure is easy to repair and replace. When a part of the mold is damaged, the corresponding part can be replaced separately without replacing the entire mold, which reduces maintenance costs and time. The use of tungsten carbide mold cores improves the wear resistance of the mold. Compared with traditional mold steel mold cores, the mold service life is extended by 30%-40%, the frequency of mold replacement is reduced, and production costs are reduced. The cooling method that combines air cooling and mist cooling ensures the uniformity of profile cooling. The method of air cooling first and then mist cooling avoids internal stress concentration caused by rapid cooling of the profile and reduces residual stress caused by uneven cooling. The profiles produced using this cooling method have residual stress reduced by 40%-50% compared with traditional cooling methods, which improves the dimensional stability of the profile and reduces deformation of the profile during subsequent processing and use.

[0049] Example 4: Powder metallurgy raw material extrusion process

[0050] Step 1, raw material preparation: Aluminum alloy powder is prepared by atomization method, and 6082 aluminum alloy composition is selected. 6082 aluminum alloy has high strength and good machinability and is often used to manufacture large structural parts. The aluminum alloy is heated to 750-800℃ in a high-temperature furnace to make it completely melted. The furnace adopts induction heating method, and the aluminum alloy is heated by eddy current generated by electromagnetic induction. This heating method has the characteristics of fast heating speed and uniform temperature. Then, it is atomized by high-pressure gas (such as argon). The high-pressure gas pressure is 10-15MPa, and the molten aluminum alloy is atomized into fine powder particles. The powder particle size is controlled In the 20-50μm, inert gas properties of argon can prevent aluminum alloy powder from oxidizing at high temperature during atomization. The powder is graded and screened using vibration screening equipment. The mesh size of the screen is selected according to the powder particle size requirements to remove coarse and fine particles and improve the uniformity of the powder. The screened powder is placed in a vacuum drying oven and dried at 120℃ for 4 hours with the vacuum degree controlled at 10-20Pa to remove moisture from the powder and prevent defects such as pores in the subsequent processing. During the drying process, the temperature sensor and vacuum sensor in the oven are used to monitor and record data in real time to ensure that the drying process meets the requirements;

[0051] Step 2, mold and molding: Design an extrusion mold with a special compaction structure. The mold consists of a mold sleeve, a mold core and a multi-stage compaction mechanism. The multi-stage compaction mechanism includes a pre-compacting area, a main compacting area and a fine compacting area. The mold material is made of high-strength alloy steel and surface hardened to improve the wear resistance and compressive strength of the mold. The dried aluminum alloy powder is loaded into the extrusion cavity of the mold. At room temperature, it is preliminarily compacted at a pressure of 50MPa by the pre-compacting mechanism. The pre-compacting time is 1-2 minutes to make the powder initially formed. During the pre-compacting process, the powder particles begin to approach each other to form a certain bonding force, and then It is sent to the main compaction area and further compacted at a pressure of 150MPa for 2-3 minutes to increase the density of the billet. During the main compaction stage, the gaps between the powder particles are further reduced and the combination is more compact. Finally, the final compaction is carried out in the fine compaction area at a pressure of 200MPa for 3-4 minutes to form a billet with a certain density. During the compaction process, the pressure and displacement are monitored in real time. The data is fed back to the control system through the pressure sensor and displacement sensor to ensure uniform compaction effect. If the pressure or displacement is abnormal, the system will automatically alarm and stop the compaction process for adjustment.

[0052] Step 3. Extrusion and post-processing: Place the compacted billet into a heating furnace, heat it to 450°C, and keep it warm for 1 hour to make the billet temperature uniform. The heating furnace uses resistance wire heating and is equipped with an intelligent temperature control system to accurately control the heating temperature and time. The temperature fluctuation range is controlled within ±5°C. Then place the billet into the extruder. The extruder is hydraulically driven and extrudes at an extrusion speed of 2-3mm / s. During the extrusion process, the extrusion pressure and temperature are monitored in real time. The extrusion pressure is controlled at 150-200MPa and the mold temperature is maintained at 430-460°C. By adjusting the hydraulic system of the extruder and the heating device of the mold, the extrusion process is ensured to be stable. At the same time, an online detection device is set at the discharge port of the extruder to detect the size and surface quality of the profile in real time. Once an abnormality is found, the extrusion parameters are adjusted immediately or production is stopped.

[0053] After the profile is extruded, it is cooled by isothermal quenching. The profile is quickly placed in a quenching medium (such as a molten salt bath) with a temperature of 200-250°C and kept warm for 30-60 minutes to make the temperature inside and outside the profile uniform. It is then cooled to room temperature in the air. Isothermal quenching can effectively reduce the internal stress of the profile, prevent deformation and cracking, and obtain good mechanical properties. After cooling, solution treatment is carried out. The profile is placed in a solution furnace, heated to 530°C, and kept warm for 2 hours to fully dissolve the alloy elements in the matrix to form a uniform solid solution. After solution treatment, water quenching is immediately carried out. The quenching water temperature is controlled at 20-30°C to quickly cool the profile and maintain the supersaturated state of the solid solution. Then artificial aging is carried out. The profile is placed in an aging furnace and aged at 195°C for 8 hours. Through aging treatment, the supersaturated solid solution is desolvated and precipitated, and the strengthening phase is precipitated to improve the strength and hardness of the profile. Finally, mechanical processing and surface painting are carried out. CNC processing equipment is used for mechanical processing, and drilling, milling and other processing operations are carried out according to product design requirements. Electrostatic spraying technology is used for surface painting to spray a layer of corrosion-resistant coating with a thickness of 60-80μm to improve the corrosion resistance and aesthetics of the profile.

[0054] In this embodiment, aluminum alloy profiles are produced using powder metallurgy raw materials, resulting in profiles with uniform composition and fine structure, fundamentally eliminating the segregation problem that may exist in traditional ingot casting. Testing has shown that the profiles produced using this process have a chemical composition uniformity deviation of less than ±0.5%, and the fluctuation range of various performance indicators has been reduced by more than 50%. The product quality is more stable and reliable, making it particularly suitable for high-end applications that require high material performance consistency. The special mold compaction structure and multi-stage compaction process can effectively improve the density of the billet. Through the gradual compaction of the three stages of pre-compaction, main compaction, and fine compaction, the relative density of the billet reaches more than 98%. Compared with traditional processes, the porosity and defects within the profile are significantly reduced. This not only improves the strength and toughness of the profile, but also enhances its fatigue resistance. According to tests, the fatigue life of the profile is extended by 25%-30%.

[0055] Furthermore, the isothermal quenching cooling method combined with precise heat treatment technology (solution treatment and artificial aging) can effectively control the structural transformation of the profile and obtain the ideal microstructure. This process increases the hardness of the profile by 15%-20%, the tensile strength by 20%-25%, and the yield strength by 18%-22%. The comprehensive mechanical properties are greatly improved, meeting the high-performance material requirements of complex structural parts. The powder metallurgy extrusion process can achieve near-net forming and can produce complex shapes and high-precision aluminum alloy multi-cavity profiles, reducing the workload and material waste of subsequent machining. At the same time, the online detection device and strict quality control process ensure the dimensional accuracy and surface quality of the product. The product qualification rate can reach more than 92%, reducing production costs and improving the company's market competitiveness.

[0056] Table 1: Comparison of various aspects of product quality in various embodiments

[0057]

[0058]

[0059] Table 2: Comparison of various aspects of production efficiency of various embodiments

[0060]

[0061] Table 3: Comparison of various aspects of cost control in various embodiments

[0062]

[0063] It can be seen from the above table that the four embodiments have achieved significant beneficial effects in the field of aluminum alloy multi-cavity profile extrusion production through different innovative technologies and process optimization.

[0064] Implementation method one uses intelligent temperature-controlled molds and precise monitoring systems to control wall thickness deviation to ±0.05mm and straightness error to as low as 0.3mm / m. Implementation method four uses powder metallurgy raw materials and a special mold compaction structure to achieve precise control of profile dimensions. These achievements enable profiles to meet the needs of fields with extremely high precision requirements such as aerospace and high-end equipment manufacturing, greatly reducing assembly errors and improving the reliability of the overall structure.

[0065] Furthermore, the fourth implementation method relies on powder metallurgy technology to increase the tensile strength of the profile to 240-260MPa and the yield strength to 200-220MPa. The third implementation method uses ultrasonic-assisted extrusion to refine the grains, significantly improving the elongation of the profile. The excellent mechanical properties allow the profile to be used in the automotive, construction and other fields to effectively enhance the component's load-bearing capacity, shock resistance and durability, thereby extending its service life.

[0066] Furthermore, implementation method one reduces the surface roughness to Ra0.2-1.2μm through nano-ceramic coating, and implementation method two uses high-precision molds and stable production processes to increase the product qualification rate to more than 95%. The high-quality surface quality reduces the subsequent processing steps, and the stable product consistency reduces the installation and use problems caused by quality differences, thereby improving the overall project quality.

[0067] Furthermore, the dual-die alternating extrusion mode is adopted to shorten the single-piece production time from 15 minutes in the conventional process to 9 minutes, and the daily output is increased by about 67%. It has obvious advantages in large-scale order production and can quickly respond to market demand. Implementation methods one, three, and four reduce downtime caused by die wear, equipment failure, and parameter fluctuations by optimizing die design, introducing auxiliary technology, and precise process control, thereby increasing equipment utilization from 60%-70% in the conventional process to 80%-90%, further tapping production potential and increasing output per unit time.

[0068] To sum up, in terms of product quality, each embodiment relies on technologies such as intelligent temperature-controlled molds and powder metallurgy raw materials to greatly improve the dimensional accuracy, mechanical properties and surface quality of the profiles. The wall thickness deviation and straightness error are significantly reduced, and key indicators such as tensile strength and yield strength are greatly improved. The product qualification rate is significantly improved, which can meet the needs of demanding fields such as aerospace and high-end equipment manufacturing. In terms of production efficiency, processes such as double-die alternating extrusion and ultrasonic assistance reduce downtime, improve equipment utilization, greatly shorten the production time of a single piece, and significantly increase daily output. In terms of cost control, the mold life is extended, energy consumption is reduced, and the scrap rate is reduced. The overall cost is significantly reduced, bringing considerable economic benefits to the enterprise.

[0069] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A production process for extruding aluminum alloy multi-cavity profiles, characterized in that: The following steps are involved: S1. Raw material preparation: Select aluminum alloy ingots, conduct chemical composition testing and mechanical property testing, use gradient heating or homogenization annealing treatment, and add trace rare earth elements to the raw materials; S2. Mold design and manufacturing: Design an extrusion mold with a special diverter hole structure. The diverter hole adopts a gradual aperture design or a variable angle design. A spiral guide groove is set on the inner wall of the diverter hole. The mold core adopts a mosaic structure or modular design. The mold surface is nitrided or sprayed with a nano-ceramic coating. S3. Pretreatment before extrusion: clean the ingot surface, apply high-temperature lubricant, heat the extrusion barrel, and install an ultrasonic vibration device on the inner wall of the extrusion barrel; S4, extrusion molding: put the ingot into the extrusion barrel, start the extruder, monitor the extrusion pressure and temperature in real time, adjust the extrusion speed and mold temperature, use a double-action extruder to apply reverse pressure, and set a laser rangefinder and infrared thermometer at the extruder outlet; S5. Cooling treatment: adopt segmented cooling, liquid nitrogen spray combined with air cooling, air cooling combined with mist cooling or austempering cooling; S6. Straightening and finishing: Use multi-roll straightening machine for straightening, use laser scanning technology to monitor deformation, and use electrolytic polishing or mechanical polishing for surface finishing; S7, aging treatment: artificial aging or natural aging is carried out, a circulating hot air system is set in the aging furnace, and a staged aging method is adopted; S8. Inspection and packaging: The profiles are inspected for dimensional accuracy, mechanical properties and surface quality, and are packaged and stored after passing the inspection.

2. The aluminum alloy multi-cavity profile extrusion production process according to claim 1, characterized in that: In the step S1, the gradient heating is to first heat the ingot to 400-450°C at a rate of 15°C / min, keep it warm for 1-2 hours, then heat it to 480-520°C and keep it warm for 2-4 hours, and then heat it to 450-470°C for homogenization annealing, keep it warm for 4-6 hours, and the amount of rare earth elements added is 0.05-0.2%.

3. The aluminum alloy multi-cavity profile extrusion production process according to claim 1, characterized in that: In S2, the aperture of the gradual diversion hole at the feed end is 18-20 mm, the aperture of the discharge end is 10-12 mm, the angle between the feed end of the variable-angle diversion hole and the mold axis is 30°, the angle between the discharge end is 15°, the pitch of the spiral guide groove is 10-20 mm, and the depth is 0.5-1 mm. The key parts of the inlaid mold core are inlaid with hard alloy, and the modular mold core is connected to the mold body by positioning pins and bolts.

4. The aluminum alloy multi-cavity profile extrusion production process according to claim 1, characterized in that: The high-temperature lubricant is made by mixing nano-scale molybdenum disulfide and high-temperature resistant resin. The particle size of the nano-scale molybdenum disulfide is 50-100nm. The frequency of the ultrasonic vibration device is 20-40kHz, and the opening time is 1-2 minutes.

5. The aluminum alloy multi-cavity profile extrusion production process according to claim 1, characterized in that: In the above-mentioned S4, the extrusion speed is 3-5 mm / s, the extrusion pressure is controlled at 80-120 MPa, the mold temperature is controlled at 460-490° C., and the reverse pressure applied by the double-action extruder is 10-20% of the extrusion pressure.

6. The aluminum alloy multi-cavity profile extrusion production process according to claim 1, characterized in that: In the S5, the first section of strong wind cooling has a wind speed of 10-15m / s, and the profile temperature is reduced to 300-350°C. The second section of water mist cooling has a water mist particle diameter controlled at 5-10μm, and the profile temperature is reduced to 200-250°C. The third section of natural cooling is to room temperature. When liquid nitrogen spray is combined with air cooling, the liquid nitrogen spray pressure is 0.5MPa, and the droplet diameter is about 3μm. When air cooling and mist cooling are combined, the air cooling wind speed is 10-12m / s, and the diameter of the mist cooling water mist particles is 5-10μm. The profile is placed in a quenching medium at 200-250°C for isothermal quenching cooling and kept warm for 30-60 minutes.

7. The aluminum alloy multi-cavity profile extrusion production process according to claim 1, characterized in that: In the above S6, the straightness of the profile is controlled within 0.5 mm / m by a multi-roll straightening machine, a mixed solution of phosphoric acid, sulfuric acid and chromic anhydride is used as an electrolytic polishing electrolyte, and the surface finish of the profile reaches Ra 0.8-1.6 μm by mechanical polishing.

8. The aluminum alloy multi-cavity profile extrusion production process according to claim 1, characterized in that: In the S7, the artificial aging temperature is 180-200°C for 6-8 hours, the natural aging is placed at room temperature for 72 hours, the circulating hot air flow rate is 5-10m / s, and the staged aging is first performed at 180-190°C for 3-4 hours, and then the temperature is raised to 190-200°C for 3-4 hours.

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