Aluminum 7003 · temper
Aluminum 7003-O
Properties of the O condition, compared with the other 7003 tempers.
Pick when maximum ductility for bending, forming or straightening is required before re-heat-treating.
What is 7003-O?
7003-O is 7003 in the O temper — pick when maximum ductility for bending, forming or straightening is required before re-heat-treating. 7003-O has a yield strength of 85 MPa (12.3 ksi) and a tensile strength of 175 MPa (25.4 ksi) — weaker than 89% of aluminum grades. Elongation at break is 18% and the elastic modulus is 70 GPa (10.2 Msi). 7003-O has a density of 2.78 g/cm³ (0.1 lb/in³), heavier than 74% of aluminum grades. It melts at 605°C (1,121 °F).
Advantages
- High service temperature — 200°C (392 °F), better than 90% of aluminum grades
- Forms and bends easily — 80/100, better than 89% of aluminum grades
- Ductile — tolerates forming and impact — 18%, better than 86% of aluminum grades
- High electrical conductivity — 45 % IACS, better than 86% of aluminum grades
- Conducts heat well — 170 W/m·K (98.2 BTU/hr·ft·°F), better than 82% of aluminum grades
Limitations
- Low strength — 85 MPa (12.3 ksi), worse than 89% of aluminum grades
- Difficult to machine — 40/100, worse than 80% of aluminum grades
7003-O properties
Typical room-temperature values for 7003-O — 10 properties are specific to this condition; the rest are grade-level values shared by every 7003 temper. Each bar shows where the value sits among the aluminum grades in FabDigit's library — further right is higher.
Physical3
7003-O has a density of 2.78 g/cm³ (0.1 lb/in³), heavier than 74% of aluminum grades. It melts at 605°C (1,121 °F).
Mechanical13
7003-O has a yield strength of 85 MPa (12.3 ksi) and a tensile strength of 175 MPa (25.4 ksi) — weaker than 89% of aluminum grades. Elongation at break is 18% and the elastic modulus is 70 GPa (10.2 Msi).
Thermal6
7003-O is rated for continuous service to 200°C (392 °F). It conducts heat at 170 W/m·K (98.2 BTU/hr·ft·°F), better than 82% of aluminum grades. Thermal expansion is 23.2 µm/m·K (12.9 µin/in·°F).
Electrical3
7003-O conducts electricity at 45 % IACS, better than 86% of aluminum grades.
Chemical & Environmental3
Corrosion resistance is good (55/100), worse than 51% of aluminum grades.
Sustainability4
Producing a kilogram of 7003-O takes about 205 MJ of energy and emits 12.5 kg of CO₂ — more than 75% of aluminum grades. Typical recycled content is 30%.
Manufacturability7
7003-O's machinability is fair (40/100, worse than 80% of aluminum grades); weldability very good (75/100); 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 7003 tempers and conditions
7003 is also supplied in 4 other conditions. The full side-by-side table is on the 7003 overview.
- T6Standard stocked condition for structural profiles and bicycle/motorcycle frames where peak strength and hardness are wanted.315 MPa yield · 105 HB
- T5Cheapest high-strength route for 7003 profiles: press-quench then age, giving ~90 % of T6 strength without a separate solution treatment.280 MPa yield · 98 HB
- T7Over-aged condition traded ~8–12 % strength for markedly better stress-corrosion resistance and dimensional stability in humid/chloride service.275 MPa yield · 95 HB
- T4Use when parts must be formed or welded before final artificial aging; Al-Zn-Mg keeps aging at room temperature so strength drifts upward.195 MPa yield · 80 HB
- OPick when maximum ductility for bending, forming or straightening is required before re-heat-treating.85 MPa yield · 45 HB
Working with 7003-O
Is 7003 easy to machine?
Machines well in T5/T6 with sharp carbide tools, high speed and flood coolant; softer O/T4 tempers tend to gum and smear.
Can 7003 be welded?
One of the more weldable 7xxx alloys — MIG/TIG with 5356 or 5183; the HAZ partially re-strengthens by natural aging, but avoid heavy restraint and consider post-weld aging to limit SCC.
Can 7003 be formed, bent or molded?
Excellent extrudability with low quench sensitivity (press-quench to T5); bend and hydroform in O or T4 and age afterwards, since T6 tubing cracks at tight radii.
What surface finishes work on 7003?
Takes clear and hard anodizing well (slightly yellow-grey tint), also chromate/Ti-Zr conversion coating and powder paint; polish before anodizing for cosmetic frames.
7003 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 | ≤ 0.3 | — |
| Fe | ≤ 0.35 | — |
| Cu | ≤ 0.2 | — |
| Mn | ≤ 0.3 | — |
| Mg | 0.5 – 1 | 0.75 |
| Cr | ≤ 0.2 | — |
| Zn | 5 – 6.5 | 5.8 |
| Zrgrain refiner / recrystallisation inhibitor | 0.05 – 0.25 | 0.15 |
| Ti | ≤ 0.2 | — |
| Others (each)0.15 total | ≤ 0.05 | — |
| Al | balance | — |
7003-O — frequently asked
What is 7003-O used for?
7003-O is typically used for bumper beams, bicycle frame tubing, motorcycle structural extrusions, automotive crash boxes and crush cans, vehicle chassis and subframe profiles and high-strength extruded structural sections. In short: weldable 7xxx extrusion.
What is the yield strength of 7003-O?
7003-O has a typical yield strength of 85 MPa (12.3 ksi) and a tensile strength of 175 MPa (25.4 ksi) — weaker than 89% of aluminum grades. Strength varies by condition: see the 5 listed tempers.
Is 7003-O easy to machine?
Not especially — machinability is rated fair (40/100, worse than 80% of aluminum grades). Machines well in T5/T6 with sharp carbide tools, high speed and flood coolant; softer O/T4 tempers tend to gum and smear.
Can 7003-O be welded?
Yes — weldability is rated very good (75/100). One of the more weldable 7xxx alloys — MIG/TIG with 5356 or 5183; the HAZ partially re-strengthens by natural aging, but avoid heavy restraint and consider post-weld aging to limit SCC.
What surface finishes work on 7003-O?
Takes clear and hard anodizing well (slightly yellow-grey tint), also chromate/Ti-Zr conversion coating and powder paint; polish before anodizing for cosmetic frames.
Can 7003-O be formed, bent or molded?
Excellent extrudability with low quench sensitivity (press-quench to T5); bend and hydroform in O or T4 and age afterwards, since T6 tubing cracks at tight radii.
What is the maximum service temperature of 7003-O?
7003-O is rated for continuous use to about 200°C (392 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Can FabDigit make parts in 7003-O?
Yes — 7003-O 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
- International Alloy Designations and Chemical Composition Limits for Wrought Aluminum (Teal Sheets) — The Aluminum Association (2018)
- EN 755-2 — Aluminium and aluminium alloys: extruded rod/bar, tube and profiles, mechanical properties — CEN (2016)
- ASM Handbook Vol.2 — Properties and Selection: Nonferrous Alloys — ASM International (1990)
- ASM Handbook Vol.13B / Vol.19 — Corrosion and Fatigue of Aluminium Alloys — ASM International (2005)
- Al-Zn-Mg extrusion alloy datasheets (7003/7005 profiles and bicycle tubing) — Constellium / Hydro Extrusion (2022)
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.