6063 aluminum
6063 extrusion temper, thickness and specification limits, with boundaries for architectural finishes, joining and service performance.
Tags: materials, aluminum, extrusions
On this page
Alloy identity and product selection
For 6063-T6 with an 8 mm wall and a 12 mm web, Hydro's European table (Rev. 4, March 2023, EN 755-2:2016) gives 160 MPa minimum proof stress and 195 MPa minimum tensile strength for the whole profile. The dimensions straddle 10 mm, so the lowest values govern. Hydro European profile data
6063 is a wrought aluminum–magnesium–silicon alloy. The Aluminum Association's Teal Sheets, revised December 2025, specify silicon at 0.20–0.60% and magnesium at 0.45–0.90% by mass. 6063A is separately registered, with different composition limits; do not drop its suffix when comparing or ordering material. Aluminum Association, Teal Sheets, 6063/6063A entries
Hydro emphasizes 6063 for architectural and appearance-sensitive extrusions, with T5, T6 and T66 among available tempers. Such descriptions help shortlist a material; they do not establish allowable loading or approval of a railing, window system or other finished assembly. Hydro, 6063 alloy
An adequate order identifies alloy, temper, product form, section drawing, dimensions/tolerances, product standard/edition, finish and inspection requirements. Keep solid profiles, hollow profiles, seamless tube and structural tube distinguishable. Similar names or external dimensions do not establish the same product route or inspection scope.
Temper and regional product documentation
Hydro's North American sheet distinguishes T4 natural aging from T5/T6 artificial aging. It identifies T6S5 as a supplier-specific unregistered temper, not a standard-industry designation. Hydro North America 6063 data, Revision 2019/01 (2/2019)
Preserve the complete temper on certificates and production records. A supplier's special suffix may encode a forming requirement or processing route; shortening it to “T6” can lose information. Conversely, the same general temper label does not justify combining requirements from different product standards.
Select the supplied and final condition together. If a part will be bent, welded or thermally processed, specify when final dimensions, strength and appearance are accepted. A temper designation is not a universal furnace recipe or a guarantee that every fabrication sequence preserves the delivered properties.
Extrusion minima are thickness dependent
Hydro's European datasheet Revision 4, March 2023 cites EN 755-2:2016 for extruded-profile minima:
| Temper | Wall thickness t | 0.2% proof strength, minimum | Tensile strength, minimum |
|---|---|---|---|
| T5 | t ≤ 10 mm | 130 MPa | 175 MPa |
| T5 | 10 < t ≤ 25 mm | 110 MPa | 160 MPa |
| T6 | t ≤ 10 mm | 170 MPa | 215 MPa |
| T6 | 10 < t ≤ 25 mm | 160 MPa | 195 MPa |
| T66 | t ≤ 10 mm | 200 MPa | 245 MPa |
| T66 | 10 < t ≤ 25 mm | 180 MPa | 225 MPa |
Mixed-thickness profiles spanning bands take the lowest applicable values for the whole section under its footnote. Hardness values are informational. Hydro EN AW-6063, Revision 4, p. 1
The North American sheet lists 205 MPa minimum ultimate/170 MPa minimum yield for its T6 bands. It selects properties by the section thickness providing the tension specimen. Keep this scope separate from the European rule. Hydro North America 6063 mechanical table and footnotes
Resolve the ordered specification, exact band and test provisions before receiving inspection. Record direction, specimen location, elongation gauge length and whether each value is a minimum, typical value or design allowable. A catalog value cannot replace a batch result where inspection is required, and a high batch result does not redefine the guaranteed grade.
Physical values and fatigue data
The Aluminum Association lists nominal calculated density 2.70 × 10³ kg/m³ for 6063. This supports preliminary mass estimates, not a guaranteed mass for an extrusion with dimensional tolerances, coating and attachments. Teal Sheets, calculated nominal densities
For example, a constant metal area of 500 mm² over 2 m gives volume 0.001 m³ and estimated bare mass 2.70 kg. Retain the area assumption and account for machining, holes, cut lengths and finish separately. A profile's bounding rectangle includes cavities and must not be used as its metal area.
Hydro's European fatigue example is explicitly informational and sample-specific: flat specimens parallel to extrusion, 20 ± 2°C, constant-amplitude loading and stress ratio R = 0.1. It is not a fatigue-life guarantee for a welded or notched assembly. Its elevated-temperature plots are also informational. Hydro EN AW-6063 Revision 4, pp. 2–3
Define the actual load spectrum, geometry, joints, environment and design method before assigning fatigue performance. Room-temperature tensile strength does not establish a continuous-service temperature or long-term creep limit.
Forming and finish
For bending, select the temper and qualify the actual section, direction, tooling and radius. Assess collapse, wrinkling, local thinning, twist, springback and visible marks as applicable. A thin open section and a thick hollow section need separate process evidence even when both are 6063-T6.
Hydro's North American sheet recommends specifying packaging/marking needs at quotation to protect exposed surfaces. An anodizing rating does not define color or gloss tolerances. Hydro North America 6063 surface and handling guidance
Specify critical visible faces, pretreatment, finish system and acceptance criteria with the finisher. Consider cut ends, welds, handling damage and installation interfaces. Preserve traceability through finishing without marking critical surfaces in an unapproved way. An architectural application list is not a warranty of cosmetic uniformity between batches.
Joining and heat-affected zones
Hydro's general welding guidance explains that fusion welding locally reduces strength in heat-treated aluminum. Separate unaffected parent, heat-affected zone and weld metal when evaluating a joint; a T6 certificate is not a property map for a welded frame. Hydro, aluminum welding rods and HAZ behavior
Select filler and procedure for both materials, required strength, corrosion exposure and finish. Establish preparation, distortion control and inspection requirements. Post-weld heat treatment is a separate qualified operation, not automatic restoration of the original stock condition.
For mechanical joints, evaluate the actual fastener, bearing/contact geometry, fit and load path. The alloy designation does not establish thread pullout, connection slip or a complete railing-system rating.
Corrosion and service boundaries
General corrosion resistance should not be interpreted as immunity. Evaluate moisture retention, crevices, dissimilar metals, cleaning chemicals and coating condition. Hydro's 6063 sheet specifically cautions about galvanic corrosion from direct dissimilar-metal contact. Hydro North America 6063 service guidance
Obtain application-specific evidence for immersion, aggressive chemical exposure, pressure containment or safety-critical structures. Maintain drainage, isolation/protection details and required inspection with the assembly design. Neither a raw-material certificate nor a decorative finish alone establishes finished-system compliance.