Aluminum Alloy Selection Guide
Everything you need to know about choosing the right aluminum alloy, temper, and surface treatment for industrial profiles
Last updated: January 2026
Aluminum Alloy Overview
Aluminum alloys are designated by a four-digit numbering system that identifies the primary alloying element. The most common alloys for industrial extruded profiles are from the 6xxx series (Al-Mg-Si), which offer an excellent combination of strength, corrosion resistance, and extrudability.
Understanding the 1xxx-8xxx Aluminum Alloy Series
Each aluminum alloy series is defined by its primary alloying element. Here is a quick reference:
| Series | Primary Element | Characteristics | Common Uses |
|---|---|---|---|
| 1xxx | 99%+ Pure Al | Excellent corrosion resistance, high thermal/electrical conductivity, very soft | Electrical conductors, chemical equipment, heat exchangers |
| 2xxx | Copper (Cu) | High strength, poor corrosion resistance, heat-treatable | Aerospace, military, high-performance automotive |
| 3xxx | Manganese (Mn) | Good workability, moderate strength, excellent corrosion resistance | Cooking utensils, heat exchangers, roofing sheets |
| 4xxx | Silicon (Si) | Low melting point, good fluidity | Welding wire, brazing filler, forged engine pistons |
| 5xxx | Magnesium (Mg) | High strength, excellent corrosion resistance (especially marine), non-heat-treatable | Marine structures, pressure vessels, truck/trailer bodies |
| 6xxx | Magnesium + Silicon (Mg+Si) | Good extrudability, medium-high strength, heat-treatable, excellent surface finish | Structural profiles, frames, rails, machine guards — THE industry standard for extruded profiles |
| 7xxx | Zinc (Zn) | Highest strength, heat-treatable, stress-corrosion cracking risk | Aerospace, sports equipment, high-performance structures |
| 8xxx | Other (Li, Fe, etc.) | Specialty alloys for specific applications | Lithium alloys for aerospace, iron alloys for foil |
6063-T5 vs 6061-T6: The Two Most Common Industrial Alloys
For industrial aluminum profiles, 6063 and 6061 dominate the market. Here's how they compare:
| Property | 6063-T5 | 6061-T6 |
|---|---|---|
| Tensile Strength | 185 MPa (27 ksi) | 310 MPa (45 ksi) |
| Yield Strength | 145 MPa (21 ksi) | 276 MPa (40 ksi) |
| Elongation | 12% | 12-17% |
| Hardness (Brinell) | 60 HB | 95 HB |
| Corrosion Resistance | Excellent | Very Good |
| Extrudability | Excellent (complex shapes) | Good (simpler shapes) |
| Surface Finish | Superior (best for anodizing) | Good |
| Weldability | Excellent | Good (with proper filler) |
| Cost | Lower | Higher |
| Typical Use | Architectural, frames, decorative, general structural | Heavy-duty structural, load-bearing, marine, transportation |
Choose 6063-T5 for: frames, machine guards, workstations, conveyor lines, display structures, and any application where appearance and complex cross-sections matter. Choose 6061-T6 for: load-bearing structures, heavy machinery frames, transportation equipment, and applications requiring higher mechanical strength.
Aluminum Temper Designations Explained
The temper code (after the alloy number) indicates the material's condition. For example, in '6063-T5', T5 is the temper.
As Fabricated
No special treatment. Properties depend on the forming process.
Annealed
Softest condition. Lowest strength, highest ductility. Best for extensive forming operations.
Strain Hardened
Mechanically strengthened by cold working (non-heat-treatable alloys only). H12, H14, H22, etc. indicate degree of hardening.
Solution Heat Treated + Naturally Aged
Heat treated and allowed to age at room temperature. Moderate strength. Good formability.
Cooled from Extrusion + Artificially Aged
Cooled by air after extrusion, then artificially aged. Most common temper for 6063 profiles. Good strength, excellent surface finish.
Solution Heat Treated + Artificially Aged
Full heat treatment cycle. Highest strength. Most common temper for 6061. Requires water quenching.
Enhanced T6
Optimized T6 process with controlled quenching and aging. Higher strength than standard T6 for 6063 alloy.
Surface Treatment Options for Aluminum Profiles
Surface treatment enhances corrosion resistance, appearance, and wear properties. Here are the common options:
Anodizing
Electrochemical process that grows a hard aluminum oxide layer. Excellent for decorative and architectural applications. Available in natural silver, black, gold, bronze, and custom colors.
Best for: Architectural profiles, visible structural parts, electronics enclosures
Powder Coating
Electrostatically applied dry powder, then cured in an oven. Thick, durable finish with excellent color consistency.
Best for: Outdoor structures, machine guards, fence systems, any application needing custom colors
Electrophoresis (E-coating)
Electrodeposition of paint in a liquid bath. Excellent uniformity even on complex shapes and internal surfaces.
Best for: Complex cross-sections, automotive parts, profiles requiring uniform coating inside and out
Mill Finish (No Treatment)
No surface treatment applied. Profiles will naturally form a thin oxide layer. Suitable for internal or non-visible applications.
Best for: Internal structural parts, hidden frames, cost-sensitive projects
Polishing
Mechanical or chemical polishing to achieve a mirror finish. Usually followed by anodizing for protection.
Best for: Decorative trim, display fixtures, premium retail displays
Sandblasting
Abrasive blasting to create a uniform matte surface. Often used as pre-treatment before anodizing or powder coating for better adhesion.
Best for: Pre-treatment, matte finish appearance, removing surface defects
How to Choose: Application-Based Selection Guide
Use this quick reference to match your application with the recommended alloy, temper, and surface treatment:
| Application | Recommended Alloy | Surface Treatment | Notes |
|---|---|---|---|
| Assembly Line Workstations | 6063-T5 | Anodizing or Powder Coating | Complex cross-sections needed; 6063 extrudes better |
| Machine Guards / Safety Fencing | 6063-T5 | Powder Coating (safety yellow) | Visibility and corrosion resistance matter most |
| Conveyor Systems | 6063-T5 / 6061-T6 | Anodizing (silver) | 6061 for high-load sections, 6063 for standard rails |
| Clean Room Partitions | 6063-T5 | Anodizing (natural silver) | Smooth finish, easy to clean, non-particle-shedding |
| Heavy-Duty Structural Frames | 6061-T6 | Anodizing or Mill Finish | Load-bearing requires higher strength of 6061 |
| Robot Arm Profiles | 6061-T6 | Anodizing | Precision and rigidity critical |
| Automotive / Transport | 6061-T6 | Powder Coating | Vibration resistance and strength required |
| LED Heat Sinks | 6063-T5 | Anodizing (black) | Thermal conductivity and complex fin shapes |
| Display / Retail Fixtures | 6063-T5 | Anodizing or Polishing | Aesthetics are primary concern |
| Outdoor Fencing / Railings | 6063-T5 | Powder Coating | UV and weather resistance from powder coat |
Industrial Aluminum Profile Standards: European vs National (Chinese) vs Korean
HSL Aluminum produces profiles in three major standards. Here's how they compare:
| Feature | European Standard (欧标) | National Standard (国标) | Korean Standard (韩标) |
|---|---|---|---|
| Slot Width | 10mm (T-slot) | 8mm (T-slot) | 10mm (T-slot) |
| Wall Thickness | Thicker (1.5-3.2mm) | Thinner (1.0-2.0mm) | Medium (1.5-2.5mm) |
| Strength | Higher | Standard | Medium |
| Weight | Heavier | Lighter | Medium |
| Cost | Higher | Lower | Medium |
| Common Sizes | 2020, 3030, 4040, 4545, 6060, 8080 | 2020, 3030, 4040, 5050, 6060, 8080 | 3030, 4040, 4545, 5050, 6060, 8080 |
| Typical Market | Europe, Middle East, Turkey | China, Southeast Asia, Africa | Korea, Southeast Asia |
Need help choosing the right profile?
Our engineering team can recommend the optimal alloy, temper, and surface treatment for your specific application.