Intent: Structural load capacity versus architectural extrusion complexity and anodized cosmetic surface finish.
Engineering Verdict & When to Choose Each
6061 or 6063: load requirement versus extrusion detail
By Mat Grades Editorial Desk · Updated 2026-11-14
Consider 6061 for a structural or machined component where the specified condition and available section meet the design. Consider 6063 where an extrusion supplier can deliver the required profile and cosmetic finish economically. Neither designation alone guarantees a particular extrusion tolerance or anodized appearance.
For a slim architectural profile, ask the extruder about wall thickness, die feasibility, straightness and finish consistency. A nominally stronger alloy may not be the best route to a difficult profile. For a bracket cut from bar, those profile advantages may be irrelevant, so compare machining stock and final properties instead.
Do not approve a switch by matching only the external shape. Review load, attachment details, temper and any subsequent welding. A sample should include the actual surface treatment if appearance matters. Keep the approved section drawing and supplier condition with the comparison so purchasing cannot silently replace a qualified profile with a superficially similar one.
6061 Aluminum: evidence to check
6061 Aluminum has 35 cataloged property rows. Modulus of Elasticity is reported as 69 GPa (typical; further condition not stated). Electrical Conductivity is reported as 47 % IACS (typical; O Temper). The record identifies ASTM B209 for Sheet & Plate; check its scope and ordered edition. These are source-scoped examples rather than unrestricted design allowables. Read the full row context and certificate before using a value for acceptance; an absent value is not zero or a performance failure.
6063 Aluminum: evidence to check
6063 Aluminum has 35 cataloged property rows. Modulus of Elasticity is reported as 69 GPa (typical; further condition not stated). Electrical Conductivity is reported as 58 % IACS (typical; O Temper). The record identifies ASTM B221 for Extrusions; check its scope and ordered edition. These are source-scoped examples rather than unrestricted design allowables. Read the full row context and certificate before using a value for acceptance; an absent value is not zero or a performance failure.
Four questions before approval
- Is extrusion shape or mechanical duty the main constraint?
- Are the final temper and section tolerance specified?
- Has the actual anodized finish been sampled?
- Will later welding change the approved condition?
Check the linked material records for the complete source trail. Read the methodology before comparing minimum requirements with typical measurements. No direct substitution or qualified fabrication procedure is implied.
Material Comparison
Compare verified engineering materials side by side with condition-specific mechanical properties.
| Parameter | 6061 Aluminum | 6063 Aluminum |
|---|---|---|
| Material Family | Aluminum & Aluminum Alloys | Aluminum & Aluminum Alloys |
| Subfamily | Wrought Aluminum Alloys | Wrought Aluminum Alloys |
| AA Designation | 6061 | 6063 |
| UNS Designation | A96061 | A96063 |
| ISO Designation | AlMg1SiCu | AlMg0.7Si |
| Element | 6061 Aluminum | 6063 Aluminum |
|---|---|---|
| Si (Silicon) | 0.4 – 0.8% | 0.2 – 0.6% |
| Fe (Iron) | ≤ 0.7% | ≤ 0.35% |
| Cu (Copper) | 0.15 – 0.4% | ≤ 0.1% |
| Mn (Manganese) | ≤ 0.15% | ≤ 0.1% |
| Mg (Magnesium) | 0.8 – 1.2% | 0.45 – 0.9% |
| Cr (Chromium) | 0.04 – 0.35% | ≤ 0.1% |
| Zn (Zinc) | ≤ 0.25% | ≤ 0.1% |
| Ti (Titanium) | ≤ 0.15% | ≤ 0.1% |
| OE (Other Elements Each) | OE: ≤ 0.05% each | OE: ≤ 0.05% each |
| OT (Other Elements Total) | ≤ 0.15% | ≤ 0.15% |
| Al (Aluminum) | — | — |
| Property | 6061 Aluminum | 6063 Aluminum |
|---|---|---|
| Density · TYPICALUnit: g/cm³ | 2.7 g/cm³ | 2.69 g/cm³ |
| Mechanical Parameter | 6061 AluminumO | 6063 AluminumO |
|---|---|---|
| Modulus of Elasticity · TYPICALUnit: GPa | 69 GPa | 69 GPa |
| Ultimate Tensile Strength · Cold Finished Rod & Bar · O Temper · TYPICALUnit: MPa | 124 MPa | — MPa |
| Ultimate Tensile Strength · Drawn Tube · O Temper · TYPICALUnit: MPa | — MPa | 90 MPa |
| Yield Strength (0.2% Offset) · Cold Finished Rod & Bar · O Temper · TYPICALUnit: MPa | 55 MPa | — MPa |
| Yield Strength (0.2% Offset) · Drawn Tube · O Temper · TYPICALUnit: MPa | — MPa | 48 MPa |
| Elongation (4D) · Cold Finished Rod & Bar · O Temper · TYPICALUnit: % | 25 % | — % |
| Elongation (4D) · Drawn Tube · O Temper · TYPICALUnit: % | — % | 35 % |
| Shear Strength · Cold Finished Rod & Bar · O Temper · TYPICALUnit: MPa | 83 MPa | — MPa |
| Shear Strength · Drawn Tube · O Temper · TYPICALUnit: MPa | — MPa | 69 MPa |
| Fatigue Endurance Limit (5x10^8 cycles) · Cold Finished Rod & Bar · O Temper · TYPICALUnit: MPa | 62 MPa | — MPa |
| Fatigue Endurance Limit (5x10^8 cycles) · Drawn Tube · O Temper · TYPICALUnit: MPa | — MPa | 55 MPa |
| Property | 6061 Aluminum | 6063 Aluminum |
|---|---|---|
| Electrical Conductivity · O Temper · TYPICALCategory: ELECTRICAL • Unit: % IACS | 47 % IACS | 58 % IACS |
| Coefficient of Thermal Expansion · TYPICALCategory: THERMAL • Unit: µm/(m·K) | 23.6 µm/(m·K) | 23.4 µm/(m·K) |
| Solidus Temperature · TYPICALCategory: THERMAL • Unit: °C | 582 °C | 616 °C |
| Liquidus Temperature · TYPICALCategory: THERMAL • Unit: °C | 652 °C | 654 °C |
| Thermal Conductivity · O Temper · TYPICALCategory: THERMAL • Unit: W/(m·K) | 180 W/(m·K) | 218 W/(m·K) |
| Hardness Scale | 6061 Aluminum | 6063 Aluminum |
|---|---|---|
| HB Hardness · Cold Finished Rod & Bar · O Temper · TYPICAL | 30 HB | — |
| HB Hardness · Drawn Tube · O Temper · TYPICAL | — | 25 HB |