Annealing Aluminum Explained: What It Is and How It Works

In the production and processing of industrial aluminum profiles, the annealing process is the core link in solving aluminum profile processing problems, guaranteeing product quality and broadening application scenarios – whether it is high hardness and easy to crack after extrusion molding of aluminum profiles, or the need for further bending and cutting processing, annealing can play a key role in restoring aluminum profiles to excellent performance to meet the demanding needs of different industries.
As an aluminum industry practitioners, mastering the core knowledge of the annealing process can effectively improve production efficiency, reduce losses, and create more competitive products. This article will comprehensively dismantle the definition of annealing aluminum, working mechanism, process types, application scenarios and core considerations, to help industry players thoroughly master this essential heat treatment technology.

What is aluminum annealing?

Aluminum annealing is a heat treatment process that changes the physical properties of aluminum and aluminum alloys through controlled heating and cooling, with the core function of reducing the hardness of aluminum, improving toughness and plasticity, and making aluminum profiles easier to process and use.

The core principle is: the aluminum material will be heated to the recrystallization temperature above, hold for a certain period of time, and then through a specific cooling method, so that the internal microstructure of aluminum restructuring, so as to optimize its mechanical properties.

Annealing is not an exclusive process for aluminum profiles, it is extremely common in the production of cast iron, steel and other metals and alloys, the core purpose is to promote the formation of new grains within the metal through heating, the old grain reorientation, and then through cooling to restore the metal’s key properties, and ultimately to eliminate the internal stresses, the formation of a more delicate, uniform crystalline structure, so that the material has a wider range of application scenarios.

Due to the wide variety of metals and alloys, there are differences in annealing processes, the most common of which are complete annealing and process annealing.

It should be noted that the annealing process applies to metals and alloys, for non-heat-treatable alloys, a specific way of full annealing or partial annealing is required; the annealing temperature and holding time will vary depending on the type of metal or alloy, and factors such as the size of the workpiece will also have a direct impact on the length and specific parameters of the annealing process.

The core purpose of aluminum annealing

For the production and processing of industrial aluminum profiles, the core purpose of the annealing process mainly has five points, which directly determines the feasibility of processing aluminum profiles and product quality:

Elimination of hardening produced by cold working: aluminum profiles in the extrusion, rolling, bending and other cold working process, there will be a rise in hardness, plasticity decline phenomenon, that is, hardening, annealing can effectively eliminate this problem, so that the aluminum profile to restore the soft state.

Restore plasticity and processing performance: the plasticity of the annealed aluminum profile is significantly improved, which can smoothly carry out the subsequent bending, stamping, cutting and other processing to avoid cracking, fracture and other problems during processing.

Eliminate internal stress: cold working, casting, welding and other processes, aluminum profiles will produce residual stress inside, if not eliminated in a timely manner, will lead to profile deformation, cracking, annealing allows the internal stress to be released, to protect the structural stability of aluminum profiles.

Refinement of grain structure, enhance the uniformity of the material: through annealing, the grains inside the aluminum profile will be rearranged, refinement, reduce the unevenness of the grains brought about by the performance differences, so that the mechanical properties of the profile is more stable.

Enhance the surface quality and mechanical properties: annealing can improve the surface finish of aluminum profiles, while optimizing its toughness, electrical conductivity and other key properties, so that aluminum profiles are more suitable for high-end application scenarios.

Here we need to make a special distinction: annealing and other heat treatment processes has an essential difference, the follow-up will be a detailed comparison of the core differences between the two, to help you accurately distinguish between the two, a reasonable choice.

The working principle of aluminum annealing

From the molecular level, the core of aluminum annealing is to control the heating and cooling to achieve the migration of atoms within the aluminum and the reorganization of the grain structure, thereby changing its mechanical properties. Aluminum as a metal prone to work-hardening, in the extrusion, bending and other processing, the internal microscopic grain will be deformed, with the increase in the number of times of processing, grain deformation intensified, aluminum profiles will become increasingly hard, increasingly brittle, and ultimately can not continue to process, and even cracking.

Annealing process can “reset” this deformation of the grain structure: the aluminum profile will be heated to 570 ° F ~ 770 ° F, this temperature range is higher than the recrystallization temperature of the aluminum, aluminum atoms can be provided with sufficient energy to enable their migration; after a period of heat preservation, the deformed grains will be gradually replaced by new, stress-free grains; and finally, through controlled cooling, the new grains are allowed to stabilize and take shape, thus restoring the softness and plasticity of the aluminum profile.

It should be noted that the annealing process usually needs to be carried out in a highly controlled environment, with the help of professional annealing furnaces, to ensure that the temperature, holding time, cooling rate and other parameters are precisely controllable; although it is also possible to carry out on-site or home-type annealing by means of tools such as an acetylene torch, the precision is low, and it is only suitable for scenarios that do not require a high level of performance. The cooling phase of annealing is also critical, the cooling rate will directly affect the final performance of the aluminum profile, too fast or too slow will lead to performance deviations.

The core mechanism of aluminum annealing

The microscopic changes of aluminum annealing are not achieved overnight, but are divided into three consecutive stages, each corresponding to a different structural change and performance improvement, and the three are connected to each other to ultimately achieve the optimization of the performance of aluminum profiles:

Response stage

The restitution stage is the initial stage of annealing, which occurs at a lower temperature and a shorter holding time. At this time, the atoms inside the aluminum profile to obtain a small amount of energy, began to slightly migrate, the main change is the “polygonalization” and the formation of sub-grains – X-ray diffraction and electron microscopy can be found through the observation of the number of dislocations in the center of the grain fragments is greatly reduced, the formation of sub-grain structure, dislocations, and the formation of sub-grains, and the formation of sub-grains. Subgrain structure is formed, and the dislocation network is mainly concentrated in the subgrain boundary.

As the heating temperature increases and the holding time is prolonged, the polygonization will be gradually perfected, the size of the sub-grains slowly increases, and some of the boundaries of the sub-grains will get rid of the dislocation winding. The core function of this stage is to initially eliminate the internal stresses of aluminum profiles, slightly reduce the hardness and enhance the plasticity, but there will be no obvious changes in grain structure.

Recrystallization stage

When the heating temperature rises to the recrystallization temperature, the annealing enters the recrystallization stage, which is the core stage that determines the annealing effect. At this time, the aluminum atoms get enough energy and start to migrate in large quantities, and the deformed old grains will be gradually replaced by new, stress-free grains, with almost no dislocations inside the new grains, and no dislocation concentration at the grain boundaries.

The rate of recrystallization is closely related to temperature and time, and can be expressed by the formula 1/t = ke-ᵃ/ᵀ, where a can be replaced by Q/R.

In addition to temperature and time, alloy composition also affects the recrystallization process: the addition of any impurity or alloying element to high-purity aluminum significantly increases the recrystallization temperature; whereas fluctuations in the composition of commercially pure aluminum and commercial alloys have less impact on recrystallization behavior, and commercial alloys that have undergone deep cold working are usually heated for several hours at 340°C to 410°C to complete recrystallization.

In addition, alloy composition affects grain size: common alloying elements and impurities such as copper, iron, magnesium, manganese, etc., usually reduce the grain size; chromium, iron, manganese and other limited solid solution elements, the effect of which depends on the compounds they form with other elements and their distribution state.

The recrystallization stage completely removes work-hardening, the plasticity of the aluminum profile increases dramatically and the hardness decreases significantly, while the residual stresses are completely removed and the properties are restored to what they were before machining. For heat-treatable aluminum alloys, the recrystallization stage may also be accompanied by dissolution or precipitation of intermetallic phases and changes in solute concentration.

Grain growth stage

After recrystallization is completed, if the heating is continued or the holding time is extended, it will enter the grain growth stage, at which time the newly formed grains will gradually grow and refine, and eventually form a stable grain structure. Grain growth is mainly divided into two forms: normal grain growth and abnormal grain growth.

Normal grain growth refers to the uniform, slow thickening of grains, commonly found in high-purity aluminum and its solid solution alloys, where small grains are gradually replaced by large grains, resulting in a larger average grain size, which is usually facilitated by small grains, high temperatures, and prolonged heating.

In commercial aluminum alloys, the presence of intermetallic compounds and fine impurity phases formed by manganese, chromium, and other elements will impede the movement of grain boundaries, thus inhibiting normal grain growth, and only at very high temperatures will the grains grow significantly, even to several inches in diameter.

The formation of abnormal grain growth is not only related to high temperatures, but also to factors such as small initial grain size and well-developed annealed weave. When high temperatures lead to manganese, iron, chromium and other elements of grain growth inhibition weakened or disappeared, some of the grains will grow rapidly, swallowing other grains, forming a few oversized giant grains, this situation will affect the performance uniformity of aluminum profiles, need to be avoided through process control.

Common annealing types for aluminum profiles

According to the processing needs of aluminum profiles, alloy type and performance requirements, the annealing process can be divided into a variety of types, the purpose of different types of annealing, process parameters and applicable scenarios are different, industrial production needs to be based on the actual needs of the precise selection:

Recrystallization annealing

This is the most common type of annealing in the production of aluminum profiles, mainly used for aluminum profiles after cold processing, the core purpose is to restore plasticity, eliminate work hardening, control the grain structure.

The process is characterized by heating the aluminum profile to a temperature slightly below the lower critical temperature, holding it for a longer period of time, and then cooling it. The process has no physical phase change, effectively allowing deformed grains to be replaced by new stress-free grains, and is suitable for preparing most commercial aluminum profiles for subsequent processing.

Stress relief annealing

The core purpose is to eliminate the internal residual stress of aluminum profiles after casting, welding and extrusion to avoid deformation and cracking during subsequent processing or use.

The process is characterized by heating the aluminum profile to a sufficient temperature, so that the internal dislocations can be eliminated, and then slowly cooled in still air, the whole process has no physical phase changes. It is suitable for solving the stress problem of aluminum profiles due to uneven cooling and processing deformation.

Isothermal annealing

This process requires precise mastery of the temperature-time curve of the alloy, and the core purpose is to maximize the cutting performance of aluminum profiles.

The process is characterized by heating the aluminum profile above the recrystallization temperature and holding it for a certain period of time, then rapidly cooling it down to a lower temperature and keeping it at a constant temperature for a certain period of time, so as to realize the controlled decomposition of austenite. It is suitable for aluminum profile processing which requires high cutting performance.

Diffusion annealing

It is mainly used to eliminate the compositional segregation of aluminum alloy produced in the casting process and restore the uniformity of alloy composition.

The process is characterized by: the aluminum profile is heated to a high temperature higher than the upper critical temperature, holding temperature for several hours, so that the atoms within the alloy fully diffuse, eliminating compositional differences. Usually after diffusion annealing, a secondary annealing is required to obtain the desired grain structure, which is suitable for aluminum alloy castings with uneven composition.

Incomplete annealing

Mainly applied to hypereutectoid steels.

The process is characterized by heating the material to a temperature close to the upper critical temperature and then cooling it slowly. The core purpose is to obtain spherical pearlite, improve the cutting performance of the material and reduce the hardness, which is applicable to the processing of alloys with specific requirements for hardness and cutting performance.

Complete annealing

The process is more demanding and requires precise mastery of the isothermal transformation curve and cooling transformation curve of the alloy, with the core purpose of obtaining an ideal microstructure.

The process is characterized by heating the aluminum profile above the upper critical temperature and then cooling it at a slow and highly controllable rate, suitable for high-end aluminum profiles with very high demands on microstructure and mechanical properties.

Spheroidal annealing

The core purpose is to form a spherical structure within the alloy to enhance the material’s cutting properties or to assist in cold working.

The process is characterized by heating the aluminum profile to a temperature below the lower critical temperature, holding it for several hours, with the cooling rate having little effect on the final properties, and is suitable for the preparation of high alloy aluminum profiles for machining.

Vacuum annealing

A new type of annealing technology for aluminum profiles, mainly used for high-purity aluminum profiles. The core advantage is that it can prevent the rolling oil molecules from cracking, oxidation and polymerization, and avoid defects on the surface such as oil spots and oxide films.

The process is characterized by the following: the annealing furnace is first pumped to a certain vacuum degree and then heated, a small amount of protective gas is passed into the heating process for oil removal, reducing the load on the vacuum pump, and accelerating heat transfer; more protective gas is passed into the furnace at the early stage of cooling to maintain the furnace at a slightly negative or positive pressure, and the temperature is rapidly reduced by convection fans and coolers.

This process has higher requirements for equipment, but it can retain the metallic luster and excellent performance of aluminum profiles to the maximum extent.

When is aluminum annealing required?

Aluminum annealing is not a mandatory part of aluminum profile production, but is chosen flexibly according to processing needs and performance requirements, and is mainly applied to the following 4 scenarios, covering the whole process of aluminum profile production, processing and use:

Elimination of work hardening

Aluminum profiles after bending, extrusion, rolling, stretching and other cold processing, there will be processing hardening, hardness increases, plasticity decreases, can not continue to carry out complex processing, at this time the need for annealing to eliminate the processing hardening, restore plasticity for subsequent processing to create the conditions.

For the production of complex aluminum profiles, often require multiple processing and multiple annealing, each time after processing through the annealing “reset” performance, to ensure that the final product molding qualified, stable performance.

After welding

Aluminum welding process, the weld will form around the heat-affected zone, the region due to high temperature, hardness, brittleness increase, easy to crack, affecting the welding quality and structural stability. At this time, through the annealing, can soften the heat-affected zone, restore its original mechanical properties, to ensure that the strength and toughness of the welded parts and the base material consistent.

Enhance electrical conductivity

Annealing can eliminate the dislocations and stresses within the aluminum profile, optimize the crystal structure, and thus enhance its electrical conductivity and magnetic properties, suitable for electrical and electronic fields of aluminum profiles. For example, aluminum rows used for electrical connections, after annealing, the electrical conductivity is significantly improved, which can reduce the loss of electrical energy.

Extension of product life

Residual stresses generated during cold working, casting, welding, etc., if not eliminated in time, will lead to deformation, cracking, corrosion and other problems during the use of aluminum profiles, shortening their service life. Even if the aluminum profile does not require subsequent processing, it is recommended to eliminate residual stress through annealing to enhance structural stability and ensure that it will not experience performance degradation in long-term use.

Key considerations for successful aluminum annealing

The effect of aluminum annealing depends directly on the control of process parameters and operational details. Ignoring key considerations may lead to annealing failures, uneven hardness, cracking, surface oxidation and other problems. The following 5 points are the core to ensure the success of aluminum annealing, need to focus on:

Alloy selection

Different series of aluminum alloys, its composition, recrystallization temperature, mechanical properties there are differences, corresponding to the annealing temperature, holding time is also different.

For example, the annealing temperature of 1000 series pure aluminum is about 343℃, while the annealing temperature of 2000, 5000, 7000 series alloys needs to be close to 399℃; non-heat-treatable alloys can be repeatedly annealed, while the annealing effect and repeatability of heat-treatable alloys are affected by the composition. Therefore, it is necessary to specify the type of alloy for the aluminum profile and customize the appropriate process parameters before annealing.

Control of heating and cooling rates

If the heating speed is too fast, it will lead to uneven temperature distribution inside the aluminum profile, resulting in localized insufficient annealing and performance deviation; if the cooling speed is too fast or uneven, it will generate new residual stresses, leading to deformation and cracking of the aluminum profile. Therefore, the annealing process needs to strictly control the heating rate to ensure that the aluminum profile is uniformly heated; the cooling stage needs to be based on the type of alloy, the use of slow cooling or controlled cooling, to avoid excessive speed.

Avoid surface pollution and oxidation

Aluminum’s chemical nature is active, high-temperature annealing process is easy to react with oxygen in the air to form an oxide film, affecting the surface quality of aluminum profiles and subsequent processing. In addition, oil and impurities on the surface of aluminum profiles will produce carbon particles during the annealing process, forming oil spots and contaminating the surface. Therefore, the surface of the aluminum profile needs to be thoroughly cleaned before annealing to remove oil and impurities; during the annealing process, low oxygen and low moisture protective gas can be passed to reduce oxidation and retain the metallic luster of the aluminum profile.

Adjust the heat preservation time

The thickness of the aluminum profile directly affects the annealing holding time: the thicker the thickness, the slower the heat transfer, the longer the holding time is needed to ensure that the internal reach the prescribed annealing temperature, to achieve uniform annealing; the thickness of thin aluminum profiles, the holding time can be appropriately shortened, to avoid excessive annealing resulting in low hardness.

Choose the right annealing furnace

The type of annealing furnace needs to be selected according to the production scale and product requirements: large-scale production can choose production line type annealing furnace to improve efficiency; small batch, high-precision products can use a single furnace to facilitate the precise control parameters. At the same time, the furnace atmosphere should be controlled according to the product requirements, ordinary aluminum profiles can use air atmosphere, high-end products need to use vacuum or protective gas atmosphere to avoid oxidation and pollution.

The advantages and disadvantages of aluminum annealing

In the production of aluminum profiles, the annealing process is a “double-edged sword”, there are significant advantages, there are also certain limitations, need to be weighed against the production needs of the choice:

Advantage

Enhance the plasticity and formability: the annealed aluminum profile plasticity is greatly improved, can easily complete complex bending, stamping and other processing, reduce processing difficulty and scrap rate, suitable for complex aluminum production.

Improvement of cutting performance: Reduce the hardness of aluminum profile, reduce the wear and tear of cutting tools, enhance the cutting efficiency and machining accuracy, and reduce the cost of machining.

Eliminate residual stress and prolong service life: avoid deformation and cracking of aluminum profiles during use, and enhance the structural stability and durability of products.

Optimize material uniformity and surface quality: refine the grain structure to make the mechanical properties of aluminum profiles more uniform; reduce surface oxidation and defects, and improve surface finish for subsequent spraying, welding and other treatments.

Enhancement of electrical and magnetic properties: Aluminum profiles suitable for electrical and electronic fields, improve conductivity and magnetism, and broaden the application range of products.

Disadvantage

Low production efficiency: The annealing process requires a long heating, holding and cooling cycle, which will prolong the production process of aluminum profiles and reduce the overall production efficiency.

High labor cost: In large-scale production, the annealing process requires special personnel to monitor the temperature, time and other parameters, which is difficult to operate and increases labor cost.

High energy consumption: Heating and cooling require a lot of energy consumption, which will increase production costs and have a certain impact on the environment.

High process requirements, the risk of failure: annealing on the temperature, time, cooling speed and other parameters of the requirements are extremely strict, once the parameter deviation, will lead to unqualified performance of aluminum extrusion profiles, or even scrap.

How to improve the annealing quality of aluminum extrusion profiles?

For aluminum extrusion profiles, the annealing quality directly determines the final performance of the product and market competitiveness, can start from the following four aspects, to improve the annealing quality, to avoid common defects:

Reduce surface defects

For aluminum extrusion profiles with special requirements, low oxygen, low moisture protective gas can be used as the annealing furnace atmosphere, to prevent rolling oil molecules in the volatilization process of cracking, carbon particles and oil spots, while reducing the thickness of the surface oxide film, retaining the metallic luster of the aluminum profile.

Specific operation: the furnace temperature is first heated to about 150 ℃, after loading the aluminum profile, the protective gas is passed to clean the furnace chamber, and then the temperature is raised; during the heating process, the oil film on the surface of the aluminum profile is volatilized and then discharged from the exhaust port, and at the same time, the protective gas is continuously supplemented to maintain a positive pressure in the furnace; after the oil film is completely volatilized, the furnace is subjected to high-temperature heating and heat preservation to achieve rapid recrystallization, and finally, the temperature is lowered.

Adopting vacuum annealing technology

For high-purity, high-precision aluminum extrusion profiles, it is recommended to adopt vacuum annealing technology, which can effectively prevent oxidation, polymerization and cracking of the rolling oil and avoid surface contamination and oxidation.

The key to vacuum annealing is: strictly control the sealing performance of the furnace chamber, the use of large-capacity vacuum pumps; pumped to the specified vacuum before heating, heating process into a small amount of protective gas to remove oil, accelerate heat conduction; cooling the early stage of the passage of more protective gases, to maintain a slightly negative or positive pressure in the furnace, through the convection fan and the cooler cooled down quickly, to ensure that the performance of the uniformity.

Precise temperature control

Optimize the design of the annealing furnace, adopt large air volume fan, deflector device, etc., to ensure uniform temperature inside the furnace, avoiding the local temperature is too high or too low; according to the type of alloy and thickness of the aluminum profile, set the annealing temperature and holding time accurately, and calibrate the temperature sensors regularly to avoid temperature deviation.

Optimize process parameters

According to the type of alloy, thickness and performance requirements of aluminum extrusion profiles, flexibly adjust the holding time and cooling speed: for thick-walled profiles, extend the holding time and adopt slow cooling; for thin-walled profiles, appropriately shorten the holding time and control the cooling speed to avoid deformation; for heat-treatable alloys, combine with the demand of subsequent processing, adjust the annealing parameters to ensure that the performance is up to standard.

The core difference between annealing and tempering

In the heat treatment of aluminum profiles, annealing and tempering are two easy to confuse the process, both through the heating and cooling to change the metal properties, but the core purpose, process parameters and the effect of the significant differences, the specific differences are as follows:

Different core purpose

Annealing: the core is to reduce the hardness of aluminum, enhance the plasticity and toughness, to eliminate work hardening and residual stress, so that aluminum profiles are easier to process, suitable for pre-processing preparation.

Tempering: the core is to reduce the brittleness of the metal, in a small amount to reduce the hardness at the same time, to enhance the strength and wear resistance, applicable to the need for high strength, high wear resistance products, to avoid brittle cracking of the metal due to excessive hardness.

Different temperature ranges

Annealing: The heating temperature is higher than the recrystallization temperature of the metal to ensure that the atoms migrate sufficiently to achieve grain reorganization.

Tempering: The heating temperature is lower than the critical temperature of the metal, no need to reach the recrystallization temperature, only need to eliminate the internal stress after quenching and adjust the performance.

Different effects on properties

Annealing: reduces hardness, improves plasticity, toughness, electrical conductivity and magnetism, eliminates residual stresses and improves machinability.

Tempering: slightly reduces hardness, significantly improves strength, wear resistance and toughness, makes the metal more durable, suitable for heavy-duty, wear-resistant scenarios.

Different applications in aluminum profiles

Annealing: Mainly used for aluminum profiles after cold working, to prepare for subsequent processing, or to eliminate residual stress, applicable to most aluminum profile products.

Tempering: It is mainly used for aluminum profiles that require high strength and wear resistance to enhance the durability and service life of the products.

Common application areas for annealed aluminum profiles

Annealed aluminum profiles are widely used in many industries, covering high-end manufacturing, construction, packaging and other fields due to their good plasticity, stable performance and excellent surface quality, with specific applications as follows:

Aerospace

The aerospace field has very high requirements for the light weight, formability and strength of aluminum profiles. The annealed aluminum profiles are light in weight and good in plasticity, and can be processed into complex parts such as aircraft wings, fuselage and frames, etc., and at the same time, they have good toughness and corrosion resistance, which can be adapted to the harsh environment of the aerospace industry.

Automotive field

With the advancement of automobile lightweight trend, annealed aluminum profiles are widely used in automobile body panels, engine parts, chassis parts and so on. Annealed aluminum profiles have good plasticity and can be easily formed into complex shapes, while being lightweight and corrosion-resistant, which reduces automotive fuel consumption and improves vehicle performance; in addition, annealing also prevents automotive aluminum parts from cracking and deforming during use.

Construction

Aluminum roofs, walls, window frames, curtain walls and other products in the construction field need to be annealed. The annealed aluminum profiles have excellent processing performance, can be bent and cut into various shapes according to the needs of architectural design, and at the same time have good surface quality and strong corrosion resistance, which can adapt to the harsh outdoor environment and extend the service life of the building.

Packaging

Aluminum foil, beverage cans and other packaging materials, need to have good formability and toughness, annealing process can make the aluminum material become soft, easy to shape, can be easily processed into thin aluminum foil, shaped cans and other products, and at the same time to enhance the strength of the material, to avoid packaging in the process of transportation, use of broken.

Electrical and Electronic Fields

Semiconductors, solar cells, wires, electrical connectors and other products, the conductivity of the aluminum material requires high, annealing can optimize the crystal structure of aluminum, enhance the conductivity, reduce power loss, while enhancing the plasticity of the material, easy to process into a variety of precision electrical components.

Conclusion

In summary, aluminum annealing is an indispensable heat treatment process in the production and processing of industrial aluminum profiles, and its core value lies in the solution of work hardening, elimination of residual stress, enhancement of plasticity and processing performance, so that aluminum profiles can be adapted to more complex processing needs and a wider range of application scenarios.

With the continuous development of the aluminum profile industry, annealing technology is also continuously upgraded, the application of vacuum annealing and other advanced processes to further enhance the quality and performance of annealed aluminum profiles, for the research and development of high-end aluminum profile products and production to provide support. In the future, with the continuous progress of technology, the annealing process will be more efficient, energy-saving and accurate, injecting new momentum for the high-quality development of the aluminum profile industry.