What Aluminum Grade Should I Use?

Aluminum profiles are the most widely used lightweight metal material in industrial manufacturing, building decoration, aerospace, automated equipment construction and other scenarios. However, many purchasers, designers and engineers are faced with the same core question: which grade of aluminum should I use?
The strength, corrosion resistance, processing performance, appearance and application scenarios of different aluminum grades vary greatly. Choosing the wrong grade of aluminum will lead to surface defects, processing difficulties, cost waste, and other problems, or lead to structural deformation of the equipment, corrosion and damage, significantly shorten the service life, and even lead to potential safety hazards.
In this article, we will comprehensively dismantle the core definition of aluminum grade, the characteristics of various alloy series, the advantages and disadvantages of mainstream industrial aluminum models, the core difference between 6061 and 6063, the selection of misunderstandings and professional selection techniques, to help you quickly and accurately match the grade of aluminum with the project, avoid the selection risk, and control the overall cost.

What is an Aluminum Grade?

Aluminum grade, or aluminum alloy grade, is a standardized classification system that distinguishes the composition, properties and uses of aluminum. Pure aluminum itself has the advantages of lightweight, corrosion resistance, high thermal conductivity and electrical conductivity, but the texture is soft and the mechanical strength is insufficient to meet the complex needs of industrial structures, heavy-duty equipment and other uses.

By adding copper, magnesium, silicon, manganese, zinc and other alloying elements to pure aluminum, the strength, hardness, processability, weldability, heat resistance and other properties of aluminum can be targeted to improve, and different element ratios form different grades of aluminum alloys, suitable for a variety of application scenarios.

Commonly added elements include: copper, magnesium, manganese, silicon, zinc, lithium, iron, chromium, titanium and so on.

According to the molding process, aluminum alloys are divided into two main categories, which are also common classification standards in the industry:

Deformation of aluminum alloy: molding through extrusion, rolling, forging and other processes, the use of four-digit number naming, is the mainstream type of industrial aluminum profiles, representative models 6061, 6063, 7075, etc..

Casting aluminum alloy: molded by melting and pouring molds, using three-digit number plus decimal point naming, mostly used for precision castings, representing model 356.0.

Why Aluminum Grades Matter

Many users mistakenly think that “all aluminum performance is similar, can be common”, in fact, the aluminum grade directly determines the use of product performance, service life, processing costs and safety, the core impact of the dimension is divided into five major aspects:

Mechanical Properties

Different aluminum grades of strength, hardness, toughness, anti-fatigue performance gap is huge, directly adapted to different load scenarios. 7075-T6 zinc alloy aluminum tensile strength is close to steel, suitable for heavy-duty high-pressure scenarios; 1100 pure aluminum texture is soft, only suitable for no load decorative, conductive scenarios. 2000, 6000, 7000 series can be significantly strengthened by heat treatment strength, while 1000. 3000, 5000 series can be used to enhance the strength of the aluminum, and 1000. 3000, 5000 series of aluminum, 3xxx, 5xxx series can only be hardened by cold work to improve performance.

Environmental Weathering

Aluminum comes with an oxidized protective layer, with basic rust resistance, but the alloying elements will change its corrosion resistance, suitable for different working environments. 5000 series aluminum is extremely resistant to seawater and salt spray corrosion, and is a special material for offshore engineering; 2000 copper-containing aluminum is susceptible to galvanic corrosion, and is not suitable for humid and coastal environments; 1000 high-purity aluminum is suitable for chemical storage tanks.

Precise selection can effectively avoid aluminum pitting, spalling, stress corrosion cracking, and significantly extend the service life of equipment and profiles.

Processing Adaptability

The welding, cutting, extruding and bending performance of different grades of aluminum varies significantly, which directly affects the processing difficulty and production cost. 5000 and 6000 series of aluminum have excellent welding performance and are not easy to crack; 2000 and 7075 series are difficult to weld and require a special process; 6063 has excellent extruding performance, and can be molded into complex thin-walled profiles; and 2011 and 6262 are specially designed for high-speed precision cutting.

Choosing the wrong grade will lead to production problems such as welding cracks, severe tool wear, inability to mold the preset structure, and decreased yield.

Lightweight Strength

Aluminum density is only one-third of steel, which is the core material for lightweight industrial design, and the difference between the strength and weight ratio of different grades of aluminum is obvious. 7075, 2024 high-strength aluminum can carry large loads under the premise of lightweight, which is widely used in the field of aviation and racing cars; 6061, 6111 take into account the combination of lightweight and structural strength, which is suitable for the automotive and automation equipment scenarios to effectively improve the energy efficiency of the equipment and increase the load space. The load space can be increased.

Stability

Aluminum grade determines the fatigue, creep and aging resistance, which affects the long-term stability of use. 5000 and 6000 series have strong weather resistance, and are not easy to age and deform in long-term outdoor use; 2000 and 7000 series have high temperature resistance and excellent fatigue resistance, and are suitable for high-temperature and cyclic loading working conditions.

Main Aluminum Alloy Series Explained

The commonly used deformed aluminum alloys in the industrial field are divided into seven series, and each series has clear composition, performance and positioning, which is the core basis for aluminum selection:

1000 Series

Aluminum content of 99.0% -99.99%, almost no alloy added elements, is the highest purity of aluminum series. The core advantages are extreme corrosion resistance, ultra-high electrical and thermal conductivity, dense and stable surface oxide layer. The disadvantage is that the mechanical strength is extremely low, no structural load-bearing capacity, only through the cold working of small hardening.

Applicable scenarios: conductive busbar, wire substrate, chemical tanks, food packaging foil, decorative reflective panels and other strength requirements, focusing on the purity and conductivity of the scene.

2000 Series

With copper as the core alloying element, it is a heat-treatable reinforced aluminum material with excellent strength-to-weight ratio, outstanding fatigue resistance, and strength comparable to mild steel. The shortcoming is that the copper content leads to poor corrosion resistance, easy to produce stress corrosion cracking, need to do spraying, cladding protection treatment.

Applicable scenarios: aircraft fuselage, wings, military equipment, high-performance automotive structural components and other high-stress, lightweight and rigidly required scenarios, limited to anti-corrosion protection of the working conditions.

3000 Series

With manganese as the main alloying element and no need for heat treatment to strengthen it, it realizes a balance between medium strength and high adaptability with excellent plasticity, bending and weldability, and has a very high cost performance.

Applicable scenarios: Roofing, gutters, kitchenware, cans, general industrial storage tanks, and other civil and general industrial scenarios that require medium strength and bending and molding.

4000 Series

High silicon content greatly reduces the melting point of aluminum, improves fluidity, has good heat resistance and wear resistance, core positioning for welding auxiliary materials.

Applicable scenes: welding wire, heat exchanger brazing plate, automobile piston, building cladding plate and other welding and high temperature resistant working conditions.

5000 Series

With magnesium as the core alloying element, it is the series of aluminum alloys with the best corrosion resistance, especially resistant to seawater, salt spray, chemical medium corrosion, minimal loss of strength after welding, excellent toughness and impact resistance.

Applicable scenes: ship hulls, offshore platforms, coastal equipment, chemical pressure vessels, low-temperature storage tanks, outdoor curtain walls and other harsh corrosive environments, mainstream models 5052, 5083, 5086.

6000 Series

Composed of magnesium and silicon elements, it can be strengthened by heat treatment, and is the most widely used all-round series of industrial aluminum profiles. It has excellent extrudability, cutting, welding and corrosion resistance, excellent surface texture after anodic oxidation, and balanced comprehensive performance without short board. The core models are 6061 and 6063, which correspond to two major scenarios: structural load-bearing and decorative appearance.

Applicable scenarios: automated equipment frames, architectural doors and windows, curtain walls, furniture profiles, lighting housings, precision jigs and fixtures, and most other industrial and architectural scenarios.

7000 Series

With zinc as the core alloy element and magnesium and copper elements, it is the aluminum alloy series with the highest strength, tensile strength far exceeding that of other series, and top performance in fatigue and high pressure resistance. The disadvantages are high cost, difficult to weld, poor corrosion resistance, and the need for professional protective treatment.

Applicable scenes: aviation landing gear, high-end racing car frame, rock climbing equipment, precision heavy-duty molds and other ultra-high stress, lightweight just need high-end scenes, mainstream models 7075, 7050.

Most Popular Aluminum Grades for Industrial Profiles

In the field of industrial profiles, the four major grades of 6061, 6063, 7075 and 5052 cover more than 95% of the application scenarios and are the core preferred choice for engineering selection, and the characteristics of each model and adaptability scenarios are as follows:

6061 Aluminum

6061-T6 is the most classic general-purpose structural aluminum, with magnesium and silicon as the alloying elements, the tensile strength of up to 310MPa after heat treatment reinforcement, both high strength, excellent cutting, welding and stability, suitable for all kinds of heavy-duty structural scenarios, the material supply, cost-effective and outstanding.

Core advantages: strong comprehensive mechanical properties, good load-bearing stability, easy processing and molding, suitable for most working conditions, cost control.

Limitations: general extrusion performance, complex shaped molding difficulty; salt spray environment corrosion resistance is weaker than 5000 series; surface texture is slightly inferior to 6063.

Typical applications: automation equipment frames, robot racks, conveyor equipment, heavy-duty workbench, work fixtures, automotive structural components, aviation auxiliary support structure.

6063 Aluminum

6063 is a lightweight decorative special aluminum, moderate strength, the core advantage of the ultimate extrusion performance and surface texture, can be molded thin-walled, complex, high-precision shaped profiles, anodic oxidation of the surface smooth and uniform, no color difference, decorative effect of the top.

Core advantages: excellent extrusion molding performance, no mold lines on the surface, excellent anodic oxidation effect, low processing cost, suitable for complex shapes.

Limitations: low structural strength, unable to carry heavy loads, dynamic loads, not applicable to high-strength structural scenarios.

Typical applications: architectural doors and windows, curtain walls, exterior wall decoration, LED light shells, furniture frames, exhibition display racks, lightweight decorative profiles.

7075 Aluminum

7075-T6 is the benchmark of industrial high-end high-strength aluminum, with a tensile strength of up to 570MPa, close to the density of steel, while retaining the advantages of aluminum lightweight, anti-fatigue, anti-high-pressure performance of the top.

Core advantages: the industry’s top strength, high stiffness, deformation resistance, adaptable to extreme load conditions.

Limitations: price is 2-3 times higher than 6061, extremely difficult to weld, poor corrosion resistance, high processing losses, and very high requirements for technology.

Typical applications: aerospace structural components, military equipment, racing car frame, high-end molds, rock climbing equipment, heavy-duty precision machinery components.

5052 Aluminum

5052 belongs to magnesium rust-proof aluminum, no heat treatment to strengthen the characteristics, through cold processing to enhance the strength, salt spray resistance, moisture resistance, chemical corrosion resistance far more than 6000, 7000 series, no strength decay after welding.

Core advantages: excellent rust resistance, good toughness, not easy to crack, suitable for harsh outdoor and chemical environments.

Limitations: Medium strength, not suitable for ultra-high load structural scenarios.

Typical applications: ship fittings, coastal equipment, outdoor cabinets, chemical storage tanks, truck car panels, signage.

How to Choose the Right Aluminum Grade

Aluminum selection is a key link in industrial design, structure construction and product implementation, and choosing the wrong grade will easily lead to a series of problems such as structural deformation, corrosion failure, processing scrap and budget overruns. Selection without blind trial and error, combined with the use of the environment, mechanical needs, processing technology, appearance requirements, budget costs of the five dimensions, you can quickly lock the optimal grade of aluminum.

Usage Environment

Environmental conditions directly determine the corrosion rate, aging speed and overall service life of aluminum, is the highest priority of all selection elements of the core indicators, the exclusive selection of different scenarios are as follows:

Indoor conventional environment: No moisture, no corrosive medium, no UV exposure, stable working conditions. Weight-bearing industrial frame, equipment base priority 6061; lightweight decorative, non-load-bearing display structure priority 6063, the two grades have sufficient performance, stable supply, cost-controllable, suitable for most indoor general-purpose scenes.

Outdoor open-air environment: Long-term exposure to sunlight, rain and temperature changes has basic requirements for aluminum’s anti-aging and anti-rust capabilities. Prefer 6061, 6063 two general-purpose magnesium-silicon alloy, according to the appearance of the demand with anodic oxidation, powder coating, fluorocarbon spraying and other surface processes, significantly improve the resistance to ultraviolet rays, rain corrosion resistance, to prolong the outdoor use of life.

Coastal/seawater/chemical corrosive environments: Chloride ions, acid and alkali media corrosive, ordinary aluminum is very easy to pitting, white rust, flaking failure. Strictly prohibit the use of unprotected 2000 series, 7000 series of high-strength aluminum, such alloys contain copper, zinc elements, corrosion resistance is extremely poor. Uniformly preferred 5052, 5083, 5086 and other 5000 series of magnesium alloy aluminum, inherently resistant to salt spray, seawater and chemical media erosion, is the special corrosion of harsh corrosive conditions of the rust-proof aluminum.

High temperature working condition: Conventional 6000 series, 5000 series aluminum in the high temperature environment is prone to annealing loss of strength, structural softening problems, can not guarantee the stability of the structure. Need to use 2000 series, 7000 series of heat-resistant high-strength aluminum, this kind of alloy after special ratio and heat treatment process, high temperature can still maintain stable strength and structural rigidity, suitable for high-temperature equipment, heat treatment equipment, and other special working conditions.

Mechanical Strength Requirements

Different equipment and structure of the bearing, force mode is very different, including static load bearing, dynamic impact, cyclic fatigue load, etc., need to match the corresponding aluminum grade according to the actual strength of the force, the industry’s mainstream T6 heat treatment state of the aluminum strength ranking: 7075>6061>6063>5052, accurate matching of various types of load scenarios:

Light load static decorative structure: no impact, no repeated force, only play a supporting, decorative, shielding role, the use of 6063-T5/T6 can meet the needs of use, cost-effective and excellent appearance and texture.

Medium and heavy load dynamic load-bearing structure: automation equipment frame, conveyor line bracket, jigs and fixtures, equipment base and other needs of long-term load-bearing, slight vibration of the core structure, priority 6061-T6, but also the industrial field of the largest amount of the most balanced performance of the general structure of the aluminum.

Ultra-high-load aviation-grade structure: military equipment, aviation parts, racing structures, high-load molds and other scenes requiring high strength and stiffness, choose 7075-T6, 2024 ultra-high-strength aluminum, the strength of which is close to that of steel and retains the advantages of lightweight.

Shock and fatigue resistant working conditions: long-term repeated vibration, impact load bearing bridge structure, vehicle equipment, moving parts, preferably 5052, 7075, 6082, excellent toughness and fatigue resistance, not easy to fatigue fracture, structural loosening problems.

Processing Technology

Different aluminum extrusion, welding, cutting, bending performance differences are significant, combined with the pre-processing process selection, can be avoided from the source of cracking, deformation, sticking to the knife, dimensional deviation and other production problems, significantly improve the processing yield and production efficiency:

Batch welded structural parts: Priority is given to the use of stable welding performance, heat-affected zone is not easy to fail 5052, 5083, 6063; 6061 can be welded but the weld area will be a small reduction in strength, the need to reserve performance margins; strictly avoid 7075, 2000 series of aluminum, this type of high-strength aluminum welding is very easy to crack, no special process is not recommended for welding processing.

Complex thin-walled shaped profiles: 6063 is preferred for extruded profiles with complex shapes, thin wall thicknesses and precise tolerance requirements, and its extreme extrusion mobility can perfectly replicate the fine structure, with low mold loss and high flatness of the finished product.

High-speed CNC precision cutting: High-volume precision machining, small holes, fine grooves, high-precision parts production, preferred 6061, 2011, cutting chip removal smooth, non-stick knife, tool wear, processing dimensional stability is excellent.

Bending, stretching molding parts: need to bend, stamping, stretching and shaping of plates and profiles, preferred high toughness 5000 series, 3000 series of aluminum, not easy to bend cracks, rebound deformation, molding effect is excellent.

Surface Appearance Requirements

Architectural decoration, exposed equipment, display products have higher requirements for surface texture, color uniformity and finish, while functional industrial structures focus on practicality, and can be differentiated according to the product’s exposed properties:

High-end exposed decorative scenes: curtain walls, doors and windows, LED lighting, display racks, home furnishing aluminum profiles and other direct user products, preferred 6063. native extrusion surface is delicate and smooth, very few lines, anodic oxidation, coloring, sandblasting color uniformity and translucency, texture senior, is the first choice for high-end decorative aluminum.

Industrial built-in functional structure: the internal frame of the equipment, hidden bracket, work base and other structural parts that do not need to be exposed, give priority to 6061. stronger mechanical properties, wider versatility, without the need to pursue the ultimate appearance, more cost-effective.

Corrosive environment exposed parts: coastal, chemical, outdoor exposed equipment shell and bracket, the choice of 5000 series rust-resistant aluminum, with anodic oxidation, powder coating anti-corrosion coating, while taking into account the corrosion resistance and integrity of the appearance, to avoid long-term use of rust and color.

Budget Cost

Aluminum selection needs to consider the full life cycle cost, rather than simply comparing the unit price of raw materials, mainstream aluminum comprehensive cost ranking: 6063 ≈ 6061 <5052 <2024 <7075

6061 and 6063 raw material prices are low, low processing difficulty, low maintenance costs, is the vast majority of industrial, construction and general-purpose scenarios of cost-effective first choice; salt spray, chemical and other harsh corrosive conditions, the priority of a small premium to choose 5000 series of aluminum, which can significantly reduce the late maintenance, replacement costs;

Aviation, military industry, high-end equipment and other special working conditions with rigid requirements for strength, on-demand selection of high-priced 7075, 2024 high-strength aluminum, high-end performance to match the scene requirements, to eliminate the safety hazards caused by low-priced selection of materials and the overall rework.

6061 vs 6063 Aluminum

6061 and 6063 are the two most commonly used aluminum in the industrial and architectural fields, and many users find it difficult to distinguish between the selection boundaries, and the core differences between the two are concentrated in the three major dimensions of strength, appearance, and processing performance:

Strength

Under the same T6 heat treatment state, the comprehensive strength of 6061 is 25%-40% higher than that of 6063, and the tensile strength, yield strength, hardness and fatigue resistance are leading in all aspects, so that it can meet the structural needs of heavy load, dynamic load and long-term load bearing; 6063 has moderate strength, and it is only suitable for light static scenes.

Surface texture

6063 extrusion molding surface smooth and flat, mold lines are very few, anodic oxidation color uniformity and translucent, high gloss, is a high-end decorative profiles dedicated material; 6061 surface texture is still good, but the fineness and uniformity is not as good as 6063, and the exposed decorative effect is slightly inferior.

Complementary Processing Performance

6061 has more advantages in CNC finishing scenarios, with smooth chip removal, higher precision and lower tool loss; 6063 performs better in welding scenarios, with smooth weld seams, low risk of cracking and stable performance in the heat-affected zone.

Applicable Scenarios

Select 6061: equipment frames, load-bearing structures, jigs and fixtures, heavy-duty mechanical components, industrial scenarios that require high strength and stability.

Option 6063: doors and windows curtain wall, decorative profiles, light shells, display racks, complex thin-walled molding, exposed aesthetic parts scene.

Common Mistakes When Choosing Aluminum Grades

Most of the aluminum failure, cost waste problems, are from the selection of misunderstanding, the following six types of high-frequency errors must be avoided:

Neglect the Whole Life Cycle Cost

Flavored selection of low-priced 6063 instead of 6061 to do the load-bearing structure, the initial savings in material costs, and later very easy to profile deformation, cracking, equipment failure, resulting in a high amount of maintenance, replacement, downtime losses, the overall cost of a significant surge. Selection must account for materials, processing, maintenance, loss of the full cycle cost.

Ignore the Difference in Corrosion Resistance

Ordinary aluminum only has the basic rust resistance, 2000, 7000 series in the humid, salt spray environment is extremely easy to corrode. Misuse of 6061, 7075 in coastal and chemical scenes without protection will quickly lead to white spots, pitting, structural weakening, and drastically shorten service life.

Excessive High Matching Strength

No need for ultra-high strength of the ordinary frame, decorative scenes, blindly choose high-priced 7075 aluminum, not only doubling the cost, but also the processing difficulty, poor surface effect, corrosion resistance and other issues, completely outweigh the benefits. Selection only needs to meet the load demand + reasonable safety margin can be.

Neglect Processing Technology Adaptability

Only focus on strength parameters, ignoring welding, extrusion, cutting needs. For example, if 7075 is used to make complex thin-walled profiles and welded structures, there will be molding difficulties, welding cracks, low yield and other problems, which will seriously affect the production schedule.

Neglect of Surface Treatment Adaptability

Misuse of 6061 in exposed decorative scenes will lead to uneven anodic oxidation color, obvious grain, rough texture, unable to meet the aesthetic demand; 7000 series aluminum surface treatment is prone to defects, not suitable for exterior parts.

Confusing Alloy State

The performance gap between different tempering states of the same aluminum is very large, 6063-T5 strength is lower than T6, 6061 without T6 heat treatment will directly lose about 30% of the strength, only choose the grade without looking at the state, it is very easy to have the performance of the problem does not meet the standard.

Conclusion

There is no absolute “best” aluminum grade selection, only the “most suitable”. General industrial structure priority 6061-T6, building decoration and appearance parts priority 6063, corrosion of harsh environments choose 5052/5083, ultra-high-strength high-end scenarios choose 7075.

As long as the combination of the use of the environment, mechanical load, processing technology, appearance needs and budget five core dimensions, to avoid the low-priced misunderstanding, excessive high matching, process mismatch and other issues, you can accurately select the type, taking into account the performance of the product, service life, processing efficiency and comprehensive cost.