# 6063-T5 aluminum

6063 in the T5 condition, with extrusion-specific strength limits, temper distinctions, joining effects, and cosmetic anodizing limitations.

Reviewed: 2026-10-29

Tags: materials, aluminum, tempers, extrusion

## Identity and temper

For 6063-T5 extrusions, Bonnell lists **22 ksi minimum tensile and 16 ksi minimum 0.2% offset yield** through **0.500 in** wall thickness. From **0.501 to 1.000 in**, the minima are **21 and 15 ksi**. Both rows give **8% elongation** over 2 inches or four specimen diameters. [Bonnell extrusion properties](https://bonnellaluminum.com/tech-info-resources/designing-aluminum-extrusions/)

6063-T5 combines an aluminum alloy designation with a processing condition. The alloy belongs to the heat-treatable magnesium-silicon 6000 series. Bonnell lists silicon at 0.20 to 0.60% and magnesium at 0.45 to 0.90%, with aluminum as the remainder. These are composition limits, not a measured batch analysis. [Bonnell Aluminum, Designing Aluminum Extrusions, alloy selection and composition](https://bonnellaluminum.com/tech-info-resources/designing-aluminum-extrusions/)

The European designation EN AW-6063 also appears as EN AW-AlMg0,7Si and material number 3.3208. [ELVIAL, EN AW-6063 datasheet](https://www.elvial.com/sites/default/files/2022-02/6063.pdf)

These tempers describe different thermal histories. [Bonnell Aluminum, temper definitions](https://bonnellaluminum.com/tech-info-resources/designing-aluminum-extrusions/)

| Temper | Processing distinction |
| --- | --- |
| T4 | Solution heat treatment followed by natural aging. |
| T5 | Cooling from elevated-temperature shaping followed by artificial aging. |
| T6 | Solution heat treatment followed by artificial aging. |

Hydro's note A includes straightening or flattening whose cold-work effect may not be recognized in mechanical properties. Hydro groups T52 and T53 with T5, but gives them separate property ranges. For thickness through 1.000 inch, T52 has tensile strength 22 to 30 ksi and yield strength 16 to 25 ksi. T53, through 0.249 inch, has respective ranges of 13 to 21 ksi and 5 to 13 ksi. [Hydro, Alloy 6063, revision 2026/01, pages 1 and 2](https://www.hydro.com/globalassets/01-products--services/extruded-profiles/americas/ena-resources/alloy-data-sheets/hydro_2026_data_sheet_6063-rev-062026.pdf)

**Synthesis.** T5 alone does not establish stress relief. The suffix identifies a material state, not a strength ranking that can replace the complete specification. A T6 requirement does not establish that T5 is acceptable, even when both products have the same alloy chemistry. The distinction between alloy and condition is covered in [grades, tempers and conditions](../grades-tempers-and-conditions.md).

## Extrusion form and strength limits

Hydro describes 6063 products including architectural profiles, solid shapes, heat sinks, and seamless or structural tube and pipe. [Hydro, Alloy 6063, page 1](https://www.hydro.com/globalassets/01-products--services/extruded-profiles/americas/ena-resources/alloy-data-sheets/hydro_2026_data_sheet_6063-rev-062026.pdf)

Bonnell lists these 6063-T5 extrusion minima. Yield means 0.2% offset yield strength. Elongation uses a 2-inch or four-diameter specimen basis. [Bonnell Aluminum, mechanical properties table](https://bonnellaluminum.com/tech-info-resources/designing-aluminum-extrusions/)

| Wall thickness, inches | Minimum ultimate tensile strength, ksi | Minimum yield strength, ksi | Minimum elongation, % |
| --- | --- | --- | --- |
| Through 0.500 | 22 | 16 | 8 |
| 0.501 to 1.000 | 21 | 15 | 8 |

**Calculated unit example.** Since 1 ksi is approximately 6.89476 MPa, 22 ksi converts to approximately 151.7 MPa and 16 ksi to 110.3 MPa. A published metric table can use rounded numbers. A conversion is not a new acceptance requirement. MPa and N/mm² express the same stress unit.

Hydro's footnotes tie mechanical properties to the cross-section thickness where the tension specimen originates. Its elongation test is not required below 0.062 inch or where a standard specimen cannot be obtained. [Hydro, Alloy 6063, page 2, notes 2 and 3](https://www.hydro.com/globalassets/01-products--services/extruded-profiles/americas/ena-resources/alloy-data-sheets/hydro_2026_data_sheet_6063-rev-062026.pdf)

### European profile example

ELVIAL cites EN 755-2 without an edition. Its table title says typical properties, but its tensile and elongation headings say minimum. Hardness is information-only. The entries below retain these column labels. [ELVIAL, EN AW-6063 datasheet, mechanical properties and footnotes](https://www.elvial.com/sites/default/files/2022-02/6063.pdf)

| Profile wall thickness t, mm | Rm, MPa minimum | Rp0.2, MPa minimum | A, % minimum | A50mm, % minimum |
| --- | --- | --- | --- | --- |
| t ≤ 3 | 175 | 130 | 8 | 6 |
| 3 < t ≤ 25 | 160 | 110 | 7 | 5 |

Rm denotes ultimate tensile strength. Rp0.2 denotes 0.2% proof stress. A and A50mm identify different elongation specimen bases. ELVIAL states that the lowest specified properties govern the whole profile when its walls fall in different thickness bands. [ELVIAL, mechanical properties table](https://www.elvial.com/sites/default/files/2022-02/6063.pdf)

**Synthesis.** The Bonnell and ELVIAL tables have different thickness bands, specimen bases, and values. Their entries cannot be combined into one universal 6063-T5 minimum. Neither establishes plate properties, weld strength, a design allowable, or the properties of an unidentified lot. A specification edition, product form, dimension, and test basis define the applicable comparison.

## Extrusion, forming, and machining

Extrusion forces aluminum through a shaped die. Bonnell notes that large differences between adjacent wall thicknesses cause uneven extrusion and cooling conditions, which can make dimensions harder to hold. [Bonnell Aluminum, circumscribing circle and wall thickness sections](https://bonnellaluminum.com/tech-info-resources/designing-aluminum-extrusions/)

ELVIAL identifies T4 as a bending condition and rates T5 and T6 machining behavior more favorably than T4 on its qualitative scale. The sheet supplies no cutting speed, bend radius, or springback value. [ELVIAL, main properties and machining characteristics](https://www.elvial.com/sites/default/files/2022-02/6063.pdf)

**Synthesis.** Extrudability does not establish a producer's minimum wall, press envelope, straightness, or finished-part tolerance. A qualitative machining rating cannot supply feed or tool-life data. A forming operation also changes the relevant process history, so properties after forming require their own basis.

## Joining and thermal response

Heat-treatable aluminum derives strength from alloy composition and heat treatment. TWI explains that fusion welding redistributes hardening constituents in the heat-affected zone and reduces local strength. Its discussion includes the 6xxx family. Filler selection depends on weldability, joint mechanical properties, corrosion resistance, and anodic coating requirements. [TWI, Aluminium alloys, Job Knowledge 21](https://www.twi-global.com/technical-knowledge/job-knowledge/weldability-of-materials-aluminium-alloys-021)

**Synthesis for 6063-T5.** Parent-extrusion minima do not describe the weld metal or heat-affected zone. A weldable alloy still needs a joint-specific strength basis. Neither a generic weldability rating nor the T5 designation provides a qualified welding procedure, retained-strength fraction, or post-weld aging cycle.

Hydro gives T5 typical thermal conductivity as 209 W/(m·K) at 25°C. This typical physical property is not a tensile minimum. [Hydro, Alloy 6063, page 2](https://www.hydro.com/globalassets/01-products--services/extruded-profiles/americas/ena-resources/alloy-data-sheets/hydro_2026_data_sheet_6063-rev-062026.pdf)

**Synthesis.** Conductivity is not a maximum service temperature or a guaranteed heat-sink rating. The cited sources establish no T5 strength-retention curve for prolonged heating, a coating-cure exposure limit, or creep performance. Temperature, exposure duration, and the final material state remain necessary to evaluate a thermal process. The T6 conductivity or fatigue data of another source cannot fill these T5 gaps.

## Cosmetic anodizing limits

Anodizing creates an oxide layer integrated with the aluminum surface. AEC identifies alloy, process chemistry, and treatment time as factors governing coating hardness and porosity. Anodizing suitability therefore does not specify a coating thickness or performance class. [Aluminum Extruders Council, Anodizing](https://aec.org/anodizing)

TWI explains that filler composition affects the color match of anodized welds. A filler close to the parent composition often improves color match but can make sound welding harder. Cosmetic match and metallurgical soundness are separate constraints. [TWI, Achieving a good colour match when welding aluminium alloys](https://www.twi-global.com/technical-knowledge/faqs/faq-what-can-be-done-to-help-achieve-a-good-colour-match-when-welding-aluminium-alloys)

**Synthesis.** The designation 6063-T5 cannot guarantee color uniformity between lots, welded areas, or differently prepared surfaces. Alloy identity alone does not define pretreatment, gloss, dye, sealing, appearance limits, or acceptable handling marks. No customer finish specification or supplier capability follows from these generic references.

## Evidence and coverage limits

Sources reviewed on 29 October 2026 PDT. This reference describes supplied extrusion material and bounded fabrication implications. It does not certify a material lot, design a structural joint, or establish customer production settings.

| Source | Version and inspection | Coverage limit |
| --- | --- | --- |
| [Hydro, Alloy 6063](https://www.hydro.com/globalassets/01-products--services/extruded-profiles/americas/ena-resources/alloy-data-sheets/hydro_2026_data_sheet_6063-rev-062026.pdf) | Revision 2026/01, June 2026. Both pages and footnotes inspected through Hydro's live alloy index. | North American extrusion data, subject to change. |
| [Bonnell Aluminum, Designing Aluminum Extrusions](https://bonnellaluminum.com/tech-info-resources/designing-aluminum-extrusions/) | Full public technical page inspected. Revision date not stated. | Producer extrusion guidance, not a lot certificate or a complete product standard. |
| [ELVIAL, EN AW-6063](https://www.elvial.com/sites/default/files/2022-02/6063.pdf) | Complete one-page PDF text and rendered table inspected. Document revision not stated. The URL directory is not proof of issue date. | Profile data with a 3 mm T5 boundary. Standard edition and elongation method details are unspecified. |
| [TWI, Aluminium alloys](https://www.twi-global.com/technical-knowledge/job-knowledge/weldability-of-materials-aluminium-alloys-021) | Public Job Knowledge 21 article inspected. Originally published October 1996 and subsequently updated. | General alloy-family mechanisms, not a numerical 6063-T5 joint design rule. |
| [TWI, color-match FAQ](https://www.twi-global.com/technical-knowledge/faqs/faq-what-can-be-done-to-help-achieve-a-good-colour-match-when-welding-aluminium-alloys) and [AEC, Anodizing](https://aec.org/anodizing) | Public technical text inspected. Revision dates not stated. | Process relationships rather than guaranteed cosmetic acceptance. |

Earlier Hydro 2019 PDF addresses returned retrieval errors during this review. Their indexed extracts are not the basis for the numerical tables above. Full EN and Aluminum Association standards were not inspected. Exact procurement requirements, current supply availability, and acceptance evidence remain outside this reference.