Aluminum 7003 vs 7021
Aluminum · grade comparison
Aluminum 7003 and 7021 are both aluminum grades, both high strength al. 7021 is the stronger of the two: yield strength 370 MPa (53.7 ksi) against 315 MPa (45.7 ksi) for 7003, about 17% more; tensile strength follows at 415 MPa (60.2 ksi) vs 360 MPa (52.2 ksi). 7021 is harder — 125 HB against 105 HB for 7003 — which matters for wear surfaces and threads. 7003 conducts electricity better (39 % IACS vs 33 % IACS).
7021Choose it when strength drives the design, or when surface hardness matters.
7003 vs 7021: propertiesHow to read these bars
- One bar per material. A full bar is the highest value among all aluminum grades in the FabDigit library; each bar is drawn as a share of that.
- The better value (by the usual engineering direction) is in bold. Rows with no direction — density, thermal conductivity — have no bold.
- Values are typical room-temperature figures for the condition named on each card.
- Confirm against the certified mill or resin datasheet before design release.
How to read these bars
- One bar per material. A full bar is the highest value among all aluminum grades in the FabDigit library; each bar is drawn as a share of that.
- The better value (by the usual engineering direction) is in bold. Rows with no direction — density, thermal conductivity — have no bold.
- Values are typical room-temperature figures for the condition named on each card.
- Confirm against the certified mill or resin datasheet before design release.
Mechanical
Strength, stiffness, ductility and hardness at room temperature.
Bulk Modulus
Tensile Strength (Ultimate)
Yield Strength (0.2% offset)
Elongation at Break
Compressive Strength
Shear Strength
Fracture Toughness (K_IC)
Hardness, Brinell
Hardness, Vickers
Same in both: Elastic (Young's) Modulus 70 GPa10.2 Msi · Shear Modulus 26.5 GPa3.8 Msi · Poisson's Ratio 0.33 · Fatigue Strength (Endurance Limit) 130 MPa18.9 ksi
Physical
Density and transition temperatures.
Melting Point (Solidus)
Same in both: Density 2.78 g/cm³0.1 lb/in³ · Liquidus Temperature 645°C1,193 °F
Thermal
How each material carries heat and how hot it can run.
Thermal Conductivity
Specific Heat Capacity
Thermal Expansion (CTE, 20–100 °C)
Same in both: Latent Heat of Fusion 390 J/g168 BTU/lb · Max Service Temperature (continuous) 120°C248 °F · Min Service Temperature -196°C-321 °F
Electrical
Conductivity and insulation.
Electrical Conductivity
Electrical Resistivity
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Galvanic Potential (seawater, vs SCE)
Corrosion Resistance
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Machinability Rating (AISI 1212 = 100 %)
Weldability
Brazeability / Solderability
Same in both: Formability (cold) 35 / 100 · Polishability 60 / 100
Sustainability
Primary-production footprint per kilogram.
Embodied Energy (primary production)
Typical Recycled Content
Same in both: Embodied Carbon (primary production) 12.5 kg CO₂/kg · Embodied Water 1,200 L/kg144 gal/lb
Common Calculations
Ratios derived from the values above.
Specific Strength (UTS / density)
Modulus of Resilience
Thermal Diffusivity
Thermal Shock Resistance Index
Same in both: Specific Stiffness (E / density) 25.2 MN·m/kg
Strength versus weight
Yield strength against density for every aluminum grade in the FabDigit library; the compared grades are highlighted. Up and left is stronger for its weight.
Manufacturing and finishing
| Capability | 7003 | 7021 |
|---|---|---|
| Default condition | — | — |
| Relative cost | $$ Standard | $$ Standard |
| Min. machined wall | 0.5 mm | 0.5 mm |
| Best machined surface | Ra 0.8 µm | Ra 0.8 µm |
Both are offered for CNC machining and Sheet metal. Both take the same 16 finishes: Anodizing Type II, Cerakote, Chem Film (Alodine), DLC, E-Coating, Electroless Nickel (EN), Electropolishing, Epoxy Coating, Gold Plating, Hard Anodize Type III w/ PTFE, Hard Anodizing Type III, Nickel Plating and 4 more.
7003 vs 7021 — frequently asked
Is 7021 stronger than 7003?
Yes. 7021 has a typical yield strength of 370 MPa (53.7 ksi) against 315 MPa (45.7 ksi) for 7003 — about 17% more. Tensile strength is 415 MPa (60.2 ksi) vs 360 MPa (52.2 ksi).
Which is cheaper, 7003 or 7021?
Both sit in the same relative cost tier ($$, standard); the part price will be decided by machining time, tolerance and quantity rather than by the material.
Which welds better, 7003 or 7021?
7003. Its weldability rates very good (75/100) against very good (70/100) for 7021.
Ready to make it?
Upload a CAD file and FabDigit prices the part in 7003 and 7021 side by side — material, machining time, tolerance and finish in one quote. Certified material data ships with the order on request.
Typical handbook values for the conditions named above, normalised for comparison. Hardness on non-Brinell scales is converted approximately for charting only. Request certified data with your order for design-critical properties.