Aluminum 6253-T61
Temper
AA 6253 · UNS A96253
T61 = t6 variant, underaged
Underaged variant giving better ductility and bendability than T6 with most of the strength gain; used where clad sheet is still formed after ageing.
Values for the T61 condition
Other 6253 tempers and conditions
6253 is listed in 5 conditions; see the grade overview at 6253.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Annealed | Softest state — used for the cladding layer during roll bonding and for deep forming before the composite is heat treated. | 55 | 110 | 25 | 28 HB | 46 % IACS |
As fabricated | Mill state of the clad layer before the composite receives its solution/ageing treatment; no guaranteed mechanical properties. | 90 | 160 | 20 | 45 HB | 46 % IACS |
Solution heat treated and naturally aged | Intermediate strength with good remaining formability; pick when the clad panel must be bent or drawn after solution treatment. | 110 | 200 | 20 | 60 HB | 37 % IACS |
T61This page T6 variant, underaged | Underaged variant giving better ductility and bendability than T6 with most of the strength gain; used where clad sheet is still formed after ageing. | 145 | 220 | 18 | 65 HB | 39 % IACS |
T6Default Solution heat treated and artificially aged | Standard supply condition — full artificial ageing matched to the T6 cycle of the 2000/7000 series core it clads. | 220 | 255 | 13 | 80 HB | 40 % IACS |
What is 6253-T61?
6253-T61 is 6253 in the T61 temper — underaged variant giving better ductility and bendability than T6 with most of the strength gain; used where clad sheet is still formed after ageing. 6253-T61 has a yield strength of 145 MPa (21 ksi) and a tensile strength of 220 MPa (31.9 ksi) — weaker than 68% of aluminum grades. Elongation at break is 18% and the elastic modulus is 69 GPa (10 Msi). 6253-T61 has a density of 2.71 g/cm³ (0.0979 lb/in³), heavier than 51% of aluminum grades. It melts at 590°C (1,094 °F). T6 is the default condition FabDigit quotes; T61 is available on request or by drawing note.
Advantages
- Ductile — tolerates forming and impact — 18%, better than 86% of aluminum grades
- Conducts heat well — 162 W/m·K (93.6 BTU/hr·ft·°F), better than 77% of aluminum grades
- Forms and bends easily — 58/100, better than 76% of aluminum grades
6253-T61 properties
Typical room-temperature values for 6253-T61; 11 are specific to this condition. Other listed values are 6253 reference data and may not represent this condition. Bars are the position among aluminum grades.
Physical3
6253-T61 has a density of 2.71 g/cm³ (0.0979 lb/in³), heavier than 51% of aluminum grades. It melts at 590°C (1,094 °F).
Mechanical10
6253-T61 has a yield strength of 145 MPa (21 ksi) and a tensile strength of 220 MPa (31.9 ksi) — weaker than 68% of aluminum grades. Elongation at break is 18% and the elastic modulus is 69 GPa (10 Msi).
Thermal6
6253-T61 is rated for continuous service to 140°C (284 °F). It conducts heat at 162 W/m·K (93.6 BTU/hr·ft·°F), better than 77% of aluminum grades. Thermal expansion is 23.4 µm/m·K (13 µin/in·°F).
Electrical3
6253-T61 conducts electricity at 39 % IACS, better than 65% of aluminum grades.
Chemical & Environmental3
Corrosion resistance is good (60/100), better than 62% of aluminum grades.
Sustainability4
Producing a kilogram of 6253-T61 takes about 200 MJ of energy and emits 13 kg of CO₂ — less than 60% of aluminum grades. Typical recycled content is 25%.
Manufacturability6
6253-T61's machinability is good (58/100, worse than 54% of aluminum grades); weldability good (65/100); formability good (58/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 6253-T61
Is 6253 easy to machine?
Machines like a medium-strength 6000-series-T6 alloy — sharp polished-flute carbide, high surface speed and flood coolant to avoid built-up edge; gummy and prone to smearing in O/T4.
Can 6253 be welded?
Readily GTAW/GMAW welded with 4043 or 5356 filler, but the HAZ loses T6 strength and the Zn-rich clad layer can fume and locally lose its sacrificial character.
Can 6253 be formed, bent or molded?
Form in O or T4 and age afterwards; T6 clad sheet tolerates only generous bend radii (≈3–4 t) before the cladding cracks.
What surface finishes work on 6253?
Anodizes and chromate-converts well (slightly darker clear film from the Zn); the alloy is intended to be left as the outer sacrificial surface, so avoid grinding the clad layer through to the core.
6253 chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| Sispecified as 45–65 % of the actual magnesium content | 0.45 – 0.98 | 0.7 |
| Fe | ≤ 0.5 | 0.25 |
| Cu | ≤ 0.1 | 0.03 |
| Mn | ≤ 0.05 | — |
| Mg | 1 – 1.5 | 1.25 |
| Cr | 0.15 – 0.35 | 0.25 |
| Zndeliberate addition to make the alloy anodic to the clad core | 1.6 – 2.4 | 2 |
| Ti | ≤ 0.1 | — |
| Others (each) | ≤ 0.05 | — |
| Others (total) | ≤ 0.15 | — |
| Al | balance | — |
6253-T61 — frequently asked
What is 6253-T61 used for?
6253-T61 is typically used for cladding layer on Alclad sheet, corrosion-resistant clad sheet products, roofing and cladding sheet, architectural panel skins, formed sheet enclosures in outdoor atmospheres and clad duct and housing sheet. In short: alclad cladding-layer alloy; sacrificial corrosion surface; formable clad sheet.
What is the yield strength of 6253-T61?
6253-T61 has a typical yield strength of 145 MPa (21 ksi) and a tensile strength of 220 MPa (31.9 ksi) — weaker than 68% of aluminum grades. Strength varies by condition: see the 5 listed tempers.
Is 6253-T61 easy to machine?
Reasonably — machinability is rated good (58/100, worse than 54% of aluminum grades). Machines like a medium-strength 6000-series-T6 alloy — sharp polished-flute carbide, high surface speed and flood coolant to avoid built-up edge; gummy and prone to smearing in O/T4.
Can 6253-T61 be welded?
Yes — weldability is rated good (65/100). Readily GTAW/GMAW welded with 4043 or 5356 filler, but the HAZ loses T6 strength and the Zn-rich clad layer can fume and locally lose its sacrificial character.
What surface finishes work on 6253-T61?
Anodizes and chromate-converts well (slightly darker clear film from the Zn); the alloy is intended to be left as the outer sacrificial surface, so avoid grinding the clad layer through to the core.
Can 6253-T61 be formed, bent or molded?
Form in O or T4 and age afterwards; T6 clad sheet tolerates only generous bend radii (≈3–4 t) before the cladding cracks.
What is the maximum service temperature of 6253-T61?
6253-T61 is rated for continuous use to about 140°C (284 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 6253-T6 and 6253-O?
T6 is the default condition — standard supply condition — full artificial ageing matched to the T6 cycle of the 2000/7000 series core it clads. O: softest state — used for the cladding layer during roll bonding and for deep forming before the composite is heat treated. Yield strength is 220 MPa in T6 versus 55 MPa in O.
Sources
- International Alloy Designations and Chemical Composition Limits for Wrought Aluminum (Teal Sheets) — The Aluminum Association (2018)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys and Special-Purpose Materials — ASM International (1990)
- ASM Handbook Vol. 13B — Corrosion: Materials (Alclad and cladding alloys) — ASM International (2005)
- ASTM B209 — Aluminum and Aluminum-Alloy Sheet and Plate (Alclad products) — ASTM International (2021)
- FabDigit internal aluminium property compilation — FabDigit (2026)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.