Aluminum 7021
AA 7021 · EN AW-7021, AW 7021
7021 is a medium-to-high strength, low-copper Al-Zn-Mg (7000 series) alloy stabilised with zirconium, supplied mainly as extrusions, tube and sheet.
7021 tempers and conditions
7021 is supplied in 6 conditions, soft to hard.
Compare all 6 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Annealed | Choose for deep drawing, severe bending or tube forming before a full solution-treat and age cycle. | 115 | 230 | 20 | 60 HB | 40 % IACS |
Solution heat treated and naturally aged | Intermediate strength with useful ductility; used when parts must still be bent or formed and will be artificially aged (or left to self-age) afterwards. | 215 | 345 | 18 | 95 HB | 30 % IACS |
Cooled from hot working and artificially aged | Press-quenched extrusions aged without a separate solution treatment — cheaper and dimensionally stable, slightly below T6 strength. | 330 | 375 | 11 | 115 HB | 34 % IACS |
Overaged for exfoliation-corrosion resistance | Pick when chloride exposure or sustained stress makes stress-corrosion cracking the governing risk, accepting ~10 % lower strength than T6. | 330 | 380 | 12 | 115 HB | 38 % IACS |
T6, stress relieved by stretching | Use for machined plate or bar parts that must stay flat/straight after heavy metal removal. | 365 | 410 | 10 | 125 HB | 33 % IACS |
Solution heat treated and artificially aged | Default stocked condition: maximum strength for frames, tubes and structural extrusions where SCC exposure is moderate. | 370 | 415 | 12 | 125 HB | 33 % IACS |
What is 7021?
7021 is a medium-to-high strength, low-copper Al-Zn-Mg (7000 series) alloy stabilised with zirconium, supplied mainly as extrusions, tube and sheet. It is chosen where near-7075 strength is wanted together with good weldability and natural post-weld strength recovery — bicycle and motorcycle frames, ski poles, sports and defence hardware. Its limits are sensitivity to stress-corrosion cracking if over-aged incorrectly or welded with high heat input, lower toughness/strength than 7075-T6, and limited hot/cold formability in the aged tempers. 7021 has a density of 2.78 g/cm³ (0.1 lb/in³), heavier than 74% of aluminum grades. It melts at 600°C (1,112 °F). 7021 has a yield strength of 370 MPa (53.7 ksi) and a tensile strength of 415 MPa (60.2 ksi) — stronger than 85% of aluminum grades. Elongation at break is 12% and the elastic modulus is 70 GPa (10.2 Msi).
What is 7021 used for?
- Bicycle frame tubes and extrusions
- Motorcycle frame members
- Automotive bumper beams
- Ski poles
- Welded sports equipment tubing
- Defence hardware and fittings
- Structural welded extrusions
Advantages
- High strength — 370 MPa (53.7 ksi), better than 85% of aluminum grades
- Tough — resists crack growth — 30 MPa·√m (27.3 ksi·√in), better than 76% of aluminum grades
Limitations
- Limited service temperature — 120°C (248 °F), worse than 79% of aluminum grades
7021 properties
Typical room-temperature values; bars are the position among aluminum grades.
Physical3
7021 has a density of 2.78 g/cm³ (0.1 lb/in³), heavier than 74% of aluminum grades. It melts at 600°C (1,112 °F).
Mechanical13
7021 has a yield strength of 370 MPa (53.7 ksi) and a tensile strength of 415 MPa (60.2 ksi) — stronger than 85% of aluminum grades. Elongation at break is 12% and the elastic modulus is 70 GPa (10.2 Msi).
Thermal6
7021 is rated for continuous service to 120°C (248 °F). It conducts heat at 140 W/m·K (80.9 BTU/hr·ft·°F), worse than 52% of aluminum grades. Thermal expansion is 23.4 µm/m·K (13 µin/in·°F).
Electrical3
7021 conducts electricity at 33 % IACS, worse than 57% of aluminum grades.
Chemical & Environmental3
Corrosion resistance is fair (45/100), worse than 62% of aluminum grades.
Sustainability4
Producing a kilogram of 7021 takes about 200 MJ of energy and emits 12.5 kg of CO₂ — less than 60% of aluminum grades. Typical recycled content is 25%.
Manufacturability7
7021's machinability is good (62/100, better than 55% of aluminum grades); weldability very good (70/100); formability fair (35/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the aluminum family
Yield strength against density for every aluminum grade FabDigit runs. 7021 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with 7021
Is 7021 easy to machine?
Machines well in T5/T6 with sharp carbide tooling, high speed and flood or MQL lubrication; chips are short and finish is good, but avoid heavy heat build-up that locally over-ages the surface.
Can 7021 be welded?
One of the more weldable 7000-series alloys — MIG/TIG with 5183/5356 filler; the HAZ naturally re-ages back toward parent strength, but keep heat input low and avoid welding in highly stressed peak-aged sections to limit SCC risk.
Can 7021 be formed, bent or molded?
Form in O or T4; T6/T651 tolerate only large-radius bends and require generous springback allowance — press-quench extrusion or hot forming for complex shapes.
Manufacturability
The process limits FabDigit applies to 7021. Every 7021 part is priced by an engineer; design inside these and the quote comes back without a redesign loop.
CNC machining
| Machinability | Better62 / 100 |
|---|---|
| ISO material group | N.1 |
| Cutting speed (rough / finish) | 350 / 420 m/min |
| Minimum wall | 0.5 mm |
| Minimum internal radius | 1 mm |
| Drill depth limit | 8× diameter |
| Best surface (machined / polished) | Ra 0.8 / — |
| Hardenable after machining | No |
Sheet metal
| Formability | Better35 / 100 |
|---|---|
| Weldability | Better70 / 100 |
7021 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 |
|---|---|---|
| Zn | 5 – 6 | 5.5 |
| Mg | 1.2 – 1.8 | 1.5 |
| Zrgrain-structure control, replaces Cr | 0.08 – 0.18 | 0.12 |
| Si | ≤ 0.25 | |
| Fe | ≤ 0.4 | |
| Cukept low for weldability | ≤ 0.25 | |
| Mn | ≤ 0.1 | |
| Cr | ≤ 0.05 | |
| Ti | ≤ 0.1 | |
| Others (each)total 0.15 max | ≤ 0.05 | |
| Al | balance |
What surface finishes work on 7021?
Responds well to clear and hard anodising and to chromate-free conversion coatings for painting; decorative colour anodising can be slightly grey/uneven, and shot peening plus paint is common on frames for SCC protection.
Surface treatments FabDigit runs on aluminum parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
Passivation
Conversion Coating
PVD Coating
Equivalent designations
Standards and trade names that resolve to Aluminum 7021 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- Aluminum Association
- AA7021
- EN / DIN / Werkstoff-Nr.
- AW-7021AW 7021AlZn5.5Mg1.5
- Also called
- 7021-T6
How much does 7021 cost?
7021 is a standard-cost aluminum ($$), cheaper than about 62% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
7021 — frequently asked
What is 7021 used for?
7021 is typically used for bicycle frame tubes and extrusions, motorcycle frame members, automotive bumper beams, ski poles, welded sports equipment tubing and defence hardware and fittings. In short: weldable extrusion.
What is the yield strength of 7021?
7021 has a typical yield strength of 370 MPa (53.7 ksi) and a tensile strength of 415 MPa (60.2 ksi) — stronger than 85% of aluminum grades. Strength varies by condition: see the 6 listed tempers.
Is 7021 easy to machine?
Reasonably — machinability is rated good (62/100, better than 55% of aluminum grades). Machines well in T5/T6 with sharp carbide tooling, high speed and flood or MQL lubrication; chips are short and finish is good, but avoid heavy heat build-up that locally over-ages the surface.
Can 7021 be welded?
Yes — weldability is rated very good (70/100). One of the more weldable 7000-series alloys — MIG/TIG with 5183/5356 filler; the HAZ naturally re-ages back toward parent strength, but keep heat input low and avoid welding in highly stressed peak-aged sections to limit SCC risk.
What surface finishes work on 7021?
Responds well to clear and hard anodising and to chromate-free conversion coatings for painting; decorative colour anodising can be slightly grey/uneven, and shot peening plus paint is common on frames for SCC protection.
Can 7021 be formed, bent or molded?
Form in O or T4; T6/T651 tolerate only large-radius bends and require generous springback allowance — press-quench extrusion or hot forming for complex shapes.
What is the maximum service temperature of 7021?
7021 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.
How much does 7021 cost?
7021 is a standard-cost aluminum ($$), cheaper than about 62% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Can FabDigit make parts in 7021?
Yes — 7021 is available for CNC machining and sheet metal; every part is priced by an engineer rather than instantly. Upload a STEP file to get a price and a DFM check.
Sources
- EN 573-3 Aluminium and aluminium alloys — chemical composition — CEN (2019)
- International Alloy Designations and Chemical Composition Limits for Wrought Aluminum (Teal Sheets) — The Aluminum Association (2018)
- EN 755-2 Aluminium alloy 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 — Corrosion: Materials — ASM International (2005)
- Al-Zn-Mg extrusion alloy datasheets (7020/7021/7022 class) — Constellium / Alcoa (2020)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.