Aluminum 7020 · temper
Aluminum 7020-O
Properties of the O condition, compared with the other 7020 tempers.
Choose for maximum formability before forming and re-solution treating; strength is low and unstable against natural aging.
What is 7020-O?
7020-O is 7020 in the O temper — choose for maximum formability before forming and re-solution treating; strength is low and unstable against natural aging. 7020-O has a yield strength of 115 MPa (16.7 ksi) and a tensile strength of 225 MPa (32.6 ksi) — weaker than 79% of aluminum grades. Elongation at break is 17% and the elastic modulus is 70 GPa (10.2 Msi). 7020-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
- Forms and bends easily — 80/100, better than 89% of aluminum grades
- Ductile — tolerates forming and impact — 17%, better than 85% of aluminum grades
- Tough — resists crack growth — 32 MPa·√m (29.1 ksi·√in), better than 83% of aluminum grades
- Conducts heat well — 160 W/m·K (92.4 BTU/hr·ft·°F), better than 75% of aluminum grades
Limitations
- Difficult to machine — 35/100, worse than 86% of aluminum grades
- Low strength — 115 MPa (16.7 ksi), worse than 79% of aluminum grades
7020-O properties
Typical room-temperature values for 7020-O — 14 properties are specific to this condition; the rest are grade-level values shared by every 7020 temper. Each bar shows where the value sits among the aluminum grades in FabDigit's library — further right is higher.
Physical3
7020-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
7020-O has a yield strength of 115 MPa (16.7 ksi) and a tensile strength of 225 MPa (32.6 ksi) — weaker than 79% of aluminum grades. Elongation at break is 17% and the elastic modulus is 70 GPa (10.2 Msi).
Thermal6
7020-O is rated for continuous service to 150°C (302 °F). It conducts heat at 160 W/m·K (92.4 BTU/hr·ft·°F), better than 75% of aluminum grades. Thermal expansion is 23.1 µm/m·K (12.8 µin/in·°F).
Electrical3
7020-O conducts electricity at 40 % IACS, better than 72% of aluminum grades.
Chemical & Environmental3
Corrosion resistance is good (62/100), better than 67% of aluminum grades.
Sustainability4
Producing a kilogram of 7020-O takes about 200 MJ of energy and emits 12.5 kg of CO₂ — less than 60% of aluminum grades. Typical recycled content is 25%.
Manufacturability8
7020-O's machinability is fair (35/100, worse than 86% of aluminum grades); weldability very good (78/100); 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 7020 tempers and conditions
7020 is also supplied in 9 other conditions. The full side-by-side table is on the 7020 overview.
- T6Standard supply condition: peak strength for welded structural work, bridges, armour and frames.340 MPa yield · 120 HB
- T651Plate condition for machined structural parts where flatness and low residual stress matter.330 MPa yield · 118 HB
- T627020 re-solution-treated and artificially aged after forming or welding, giving T6-level peak-aged strength without producer stress relief.315 MPa yield · 113 HB
- T5Economical route for thin-wall extrusions: 7020 is press-quenchable, so aging directly off the press gives near-T6 strength with less distortion.310 MPa yield · 112 HB
- T73Specify for thick sections or chloride/humid service where stress-corrosion and exfoliation resistance outweigh a ~10 % strength loss.290 MPa yield · 108 HB
- T4517020 plate solution-treated, stretched to relieve residual stress, then naturally aged — moderate strength with good formability and low machining distortion.215 MPa yield · 88 HB
- T4Pick when parts must be bent/formed after heat treatment and then allowed to age (or later artificially aged) to full strength.210 MPa yield · 92 HB
- OChoose for maximum formability before forming and re-solution treating; strength is low and unstable against natural aging.115 MPa yield · 60 HB
Working with 7020-O
Is 7020 easy to machine?
Machines well in T6/T651 with sharp carbide tools, high speed and flood coolant; softer T4/O tempers tend to smear and build up on the edge.
Can 7020 be welded?
The most weldable 7xxx alloy — MIG/TIG with 5356 or 5183 filler, HAZ recovers most strength by natural re-aging over 2–4 weeks; avoid restraint and pre-heat to limit SCC in the HAZ.
Can 7020 be formed, bent or molded?
Form in O or T4; T6 bends need generous radii (≥3–4 t) as ductility is limited; hot forming above ~350 °C degrades the temper.
What surface finishes work on 7020?
Anodizes to a slightly grey/yellow clear film and takes hard coat well; chromate/chromate-free conversion coatings and paint are common on structural welded assemblies to combat exfoliation.
7020 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 | ≤ 0.35 | 0.15 |
| Fe | ≤ 0.4 | 0.25 |
| Cukept low for weldability | ≤ 0.2 | 0.1 |
| Mn | 0.05 – 0.5 | 0.25 |
| Mg | 1 – 1.4 | 1.2 |
| Cr | 0.1 – 0.35 | 0.2 |
| Zn | 4 – 5 | 4.5 |
| ZrZr+Ti 0.08–0.25 | 0.08 – 0.2 | 0.14 |
| Ti | ≤ 0.2 | 0.05 |
| Others (each)total 0.15 max | ≤ 0.05 | — |
| Al | balance | — |
7020-O — frequently asked
What is 7020-O used for?
7020-O is typically used for bridges, cranes and military vehicles. In short: weldable structural 7xxx.
What is the yield strength of 7020-O?
7020-O has a typical yield strength of 115 MPa (16.7 ksi) and a tensile strength of 225 MPa (32.6 ksi) — weaker than 79% of aluminum grades. Strength varies by condition: see the 10 listed tempers.
Is 7020-O easy to machine?
Not especially — machinability is rated fair (35/100, worse than 86% of aluminum grades). Machines well in T6/T651 with sharp carbide tools, high speed and flood coolant; softer T4/O tempers tend to smear and build up on the edge.
Can 7020-O be welded?
Yes — weldability is rated very good (78/100). The most weldable 7xxx alloy — MIG/TIG with 5356 or 5183 filler, HAZ recovers most strength by natural re-aging over 2–4 weeks; avoid restraint and pre-heat to limit SCC in the HAZ.
What surface finishes work on 7020-O?
Anodizes to a slightly grey/yellow clear film and takes hard coat well; chromate/chromate-free conversion coatings and paint are common on structural welded assemblies to combat exfoliation.
Can 7020-O be formed, bent or molded?
Form in O or T4; T6 bends need generous radii (≥3–4 t) as ductility is limited; hot forming above ~350 °C degrades the temper.
What is the maximum service temperature of 7020-O?
7020-O is rated for continuous use to about 150°C (302 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Can FabDigit make parts in 7020-O?
Yes — 7020-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
- EN 573-3 Aluminium and aluminium alloys — chemical composition — CEN (2019)
- EN 485-2 Aluminium sheet, strip and plate — mechanical properties — CEN (2018)
- EN 755-2 Aluminium extruded rod/bar, tube and profiles — mechanical properties — CEN (2016)
- EN 515 Aluminium wrought products — temper designations — CEN (2017)
- 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)
- EN AW-7020 (AlZn4.5Mg1) plate and extrusion datasheets — European aluminium producers (2023)
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.