Aluminum 3003 vs 3B21
Aluminum · grade comparison
Aluminum 3003 and 3B21 are both aluminum grades. 3B21 is the stronger of the two: tensile strength 175 MPa (25.4 ksi) against 150 MPa (21.8 ksi) for 3003, about 17% more. In exchange, 3003 is the more ductile: elongation 10% versus 8% for 3B21, and 3B21 is harder (44 HB vs 40 HB). On the shop floor, 3003 machines more easily (fair vs poor) and 3003 sits in a lower cost tier (budget, $) than 3B21 (standard, $$).
3003Choose it when the part is bent, formed or impact-loaded, or when the part is machined in volume.
3B21Choose it when strength drives the design.
3003 vs 3B21: 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.
Elastic (Young's) Modulus
Shear Modulus
Bulk Modulus
Tensile Strength (Ultimate)
Yield Strength (0.2% offset)
Elongation at Break
Shear Strength
Fatigue Strength (Endurance Limit)
Hardness, Brinell
Same in both: Poisson's Ratio 0.33
Physical
Density and transition temperatures.
Same in both: Density 2.73 g/cm³0.1 lb/in³ · Melting Point (Solidus) 643°C1,189 °F · Liquidus Temperature 654°C1,209 °F
Thermal
How each material carries heat and how hot it can run.
Thermal Conductivity
Latent Heat of Fusion
Same in both: Specific Heat Capacity 893 J/kg·K0.21 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 23.2 µm/m·K12.9 µin/in·°F · Max Service Temperature (continuous) 150°C302 °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).
Corrosion Resistance
Same in both: Galvanic Potential (seawater, vs SCE) -0.83 V
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Weldability
Formability (cold)
Brazeability / Solderability
Polishability
Machinability Rating (AISI 1212 = 100 %)
Sustainability
Primary-production footprint per kilogram.
Embodied Energy (primary production)
Embodied Water
Same in both: Embodied Carbon (primary production) 12.5 kg CO₂/kg · Typical Recycled Content 35%
Common Calculations
Ratios derived from the values above.
Specific Strength (UTS / density)
Specific Stiffness (E / density)
Modulus of Resilience
Thermal Diffusivity
Thermal Shock Resistance Index
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 | 3003 | 3B21 |
|---|---|---|
| CNC machining | Yes | — |
| Sheet metal | Yes | — |
| Default condition | — | — |
| Relative cost | $ Budget | $$ Standard |
| Min. machined wall | 0.5 mm | — |
| Best machined surface | Ra 0.8 µm | — |
| Anodizing Type II | Yes | — |
| Cerakote | Yes | — |
| Chem Film (Alodine) | Yes | — |
| DLC | Yes | — |
| E-Coating | Yes | — |
| Electropolishing | Yes | — |
| Hard Anodize Type III w/ PTFE | Yes | — |
| Hard Anodizing Type III | Yes | — |
| Nickel Plating | Yes | — |
| PTFE Coating | Yes | — |
| Painting | Yes | — |
| Powder Coating | Yes | — |
They share 4 finishes: Electroless Nickel (EN), Epoxy Coating, Gold Plating, Silver Plating.
3003 vs 3B21 — frequently asked
Is 3B21 stronger than 3003?
Yes. 3B21 has a typical tensile strength of 175 MPa (25.4 ksi) against 150 MPa (21.8 ksi) for 3003 — about 17% more.
Which is cheaper, 3003 or 3B21?
3003 is the lower-cost material: it sits in the budget tier ($) while 3B21 is standard ($$). Part price depends far more on geometry, tolerance and quantity than on raw stock — upload a CAD file for a live quote.
Which is easier to machine, 3003 or 3B21?
3003. Its machinability rates fair (45/100) against poor (32/100) for 3B21.
Ready to make it?
Upload a CAD file and FabDigit prices the part in 3003 and 3B21 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.