Aluminum 6063 · temper
Aluminum 6063-T42
Properties of the T42 condition, compared with the other 6063 tempers.
6063 re-solution treated from O/F stock by the fabricator and naturally aged to a stable, moderately soft T4-like condition with good formability.
What is 6063-T42?
6063-T42 is 6063 in the T42 temper — 6063 re-solution treated from O/F stock by the fabricator and naturally aged to a stable, moderately soft T4-like condition with good formability. 6063-T42 has a yield strength of 83 MPa (12 ksi) and a tensile strength of 152 MPa (22 ksi) — weaker than 89% of aluminum grades. Elongation at break is 22% and the elastic modulus is 68.9 GPa (9.99 Msi). 6063-T42 has a density of 2.7 g/cm³ (0.0975 lb/in³), lighter than 60% of aluminum grades. It melts at 615°C (1,139 °F).
Advantages
- Good corrosion resistance — 78/100, better than 94% of aluminum grades
- Ductile — tolerates forming and impact — 22%, better than 91% of aluminum grades
- High electrical conductivity — 50 % IACS, better than 90% of aluminum grades
- Readily welded — 90/100, better than 90% of aluminum grades
- Polishes to a fine finish — 75/100, better than 90% of aluminum grades
Limitations
- Low strength — 83 MPa (12 ksi), worse than 89% of aluminum grades
- Difficult to machine — 40/100, worse than 80% of aluminum grades
- Limited service temperature — 120°C (248 °F), worse than 79% of aluminum grades
6063-T42 properties
Typical room-temperature values for 6063-T42 — 34 properties are specific to this condition; the rest are grade-level values shared by every 6063 temper. Each bar shows where the value sits among the aluminum grades in FabDigit's library — further right is higher.
Physical3
6063-T42 has a density of 2.7 g/cm³ (0.0975 lb/in³), lighter than 60% of aluminum grades. It melts at 615°C (1,139 °F).
Mechanical12
6063-T42 has a yield strength of 83 MPa (12 ksi) and a tensile strength of 152 MPa (22 ksi) — weaker than 89% of aluminum grades. Elongation at break is 22% and the elastic modulus is 68.9 GPa (9.99 Msi).
Thermal6
6063-T42 is rated for continuous service to 120°C (248 °F). It conducts heat at 193 W/m·K (111.5 BTU/hr·ft·°F), better than 89% of aluminum grades. Thermal expansion is 23.4 µm/m·K (13 µin/in·°F).
Electrical3
6063-T42 conducts electricity at 50 % IACS, better than 90% of aluminum grades.
Chemical & Environmental3
Corrosion resistance is very good (78/100), better than 94% of aluminum grades.
Sustainability4
Producing a kilogram of 6063-T42 takes about 200 MJ of energy and emits 12.5 kg of CO₂ — less than 60% of aluminum grades. Typical recycled content is 35%.
Manufacturability7
6063-T42's machinability is fair (40/100, worse than 80% of aluminum grades); weldability excellent (90/100); formability very good (80/100).
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other 6063 tempers and conditions
6063 is also supplied in 12 other conditions. The full side-by-side table is on the 6063 overview.
- T832Highest-strength 6063 condition, from heavily cold-drawn tube/rod; ductility is limited so avoid post-forming.270 MPa yield · 95 HB
- T86063 solution treated, cold worked (drawn or stretched) and then peak-aged — the strongest common 6063 condition, used for precision drawn tube and rod.248 MPa yield · 82 HB
- T83Drawn tube temper giving higher yield strength than T6 with a tight tolerance, bright drawn surface.241 MPa yield · 82 HB
- T66European high-strength variant of T6 (tighter process control) used for structural window/curtain-wall profiles to EN 755-2.215 MPa yield · 78 HB
- T6Standard full-strength temper for structural profiles, tube, railings and machined parts where 6063's surface quality is wanted at maximum strength.214 MPa yield · 73 HB
- T626063 re-solution treated from O/F stock by the fabricator and peak-aged, giving full T6-level strength in parts formed or welded before heat treatment.214 MPa yield · 73 HB
- T831Lightly drawn tube temper: between T5 and T6 in strength, better bendability than T83 for tube fittings.186 MPa yield · 70 HB
- T5The volume architectural/industrial profile temper: good strength with excellent as-extruded surface and low distortion, no separate solution treatment.145 MPa yield · 60 HB
- T52Use for straight, low-residual-stress tube and bar that must hold tight tolerance during machining.145 MPa yield · 58 HB
- T4Choose when parts must be bent, spun or drawn after heat treatment and then artificially aged to T6 for final strength.90 MPa yield · 50 HB
- T1Low-cost as-extruded-and-aged condition for non-structural profiles that must still be bent or roll-formed.90 MPa yield · 42 HB
- T426063 re-solution treated from O/F stock by the fabricator and naturally aged to a stable, moderately soft T4-like condition with good formability.83 MPa yield · 46 HB
- OPick for maximum ductility in bending, deep drawing or tube forming, then age-harden to T4/T6 if strength is needed.48 MPa yield · 25 HB
Working with 6063-T42
Is 6063 easy to machine?
Machines easily but is gummy in soft tempers — use sharp polished-flute carbide tools, high surface speed, positive rake and generous coolant/lubricant to avoid built-up edge; T6/T83 give the cleanest chips.
Can 6063 be welded?
Excellent GTAW/GMAW weldability with 4043 (general) or 5356 (higher strength/anodizing match); the HAZ drops to roughly T4 strength unless re-solution-treated and aged.
Can 6063 be formed, bent or molded?
Outstanding extrudability — thin walls and intricate hollow dies are routine; bend and roll-form in O/T4/T1, keep bend radii generous in T5/T6 to avoid cracking.
What surface finishes work on 6063?
Best-in-class anodizing alloy: clear, bright-dip, electrolytic bronze/black and powder coating all give uniform streak-free finishes; mechanical polishing and chemical brightening also respond well.
6063 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 |
|---|---|---|
| Si | 0.2 – 0.6 | 0.4 |
| Feimpurity limit | ≤ 0.35 | 0.2 |
| Cu | ≤ 0.1 | 0.02 |
| Mn | ≤ 0.1 | 0.03 |
| Mg | 0.45 – 0.9 | 0.7 |
| Cr | ≤ 0.1 | 0.02 |
| Zn | ≤ 0.1 | 0.02 |
| Ti | ≤ 0.1 | 0.02 |
| Others (each)total 0.15 max | ≤ 0.05 | — |
| Alremainder, ~98.9 % nominal | balance | — |
6063-T42 — frequently asked
What is 6063-T42 used for?
6063-T42 is typically used for extruded heat sinks, architectural trim and window/door profiles, curtain-wall and framing sections, industrial T-slot and machine-build profiles, handrails and enclosure frames and tube and pipe fittings. In short: best surface finish; architectural trim.
What is the yield strength of 6063-T42?
6063-T42 has a typical yield strength of 83 MPa (12 ksi) and a tensile strength of 152 MPa (22 ksi) — weaker than 89% of aluminum grades. Strength varies by condition: see the 13 listed tempers.
Is 6063-T42 easy to machine?
Not especially — machinability is rated fair (40/100, worse than 80% of aluminum grades). Machines easily but is gummy in soft tempers — use sharp polished-flute carbide tools, high surface speed, positive rake and generous coolant/lubricant to avoid built-up edge; T6/T83 give the cleanest chips.
Can 6063-T42 be welded?
Yes — weldability is rated excellent (90/100). Excellent GTAW/GMAW weldability with 4043 (general) or 5356 (higher strength/anodizing match); the HAZ drops to roughly T4 strength unless re-solution-treated and aged.
What surface finishes work on 6063-T42?
Best-in-class anodizing alloy: clear, bright-dip, electrolytic bronze/black and powder coating all give uniform streak-free finishes; mechanical polishing and chemical brightening also respond well.
Can 6063-T42 be formed, bent or molded?
Outstanding extrudability — thin walls and intricate hollow dies are routine; bend and roll-form in O/T4/T1, keep bend radii generous in T5/T6 to avoid cracking.
What is the maximum service temperature of 6063-T42?
6063-T42 is rated for continuous use to about 120°C (248 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Can FabDigit make parts in 6063-T42?
Yes — 6063-T42 is available for CNC machining and sheet metal with instant online pricing. Upload a STEP file to get a price and a DFM check.
Sources
- Aluminum Standards and Data (Teal Sheets) — alloy 6063 registration and temper limits — The Aluminum Association (2018)
- ASTM B221 — Aluminum-Alloy Extruded Bars, Rods, Wire, Profiles and Tubes — ASTM International (2021)
- ASTM B241/B429 — extruded/drawn aluminum tube — ASTM International (2020)
- EN 755-2 — Aluminium and aluminium alloys, extruded rod/bar/tube/profiles: mechanical properties — CEN (2016)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys, wrought 6xxx data — ASM International (1990)
- ASM Specialty Handbook: Aluminum and Aluminum Alloys — ASM International (1993)
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.