Aluminum 3005 vs 3B21
Aluminum · grade comparison
Aluminum 3005 and 3B21 are both aluminum grades. Both yield at about 155 MPa — strength does not separate them. 3B21 is the more ductile: elongation 8% versus 5% for 3005, and 3005 is harder (48 HB vs 44 HB). 3B21 runs hotter in service (150°C vs 120°C continuous). On the shop floor, 3005 sits in a lower cost tier (budget, $) than 3B21 (standard, $$).
3005Choose it when cost is the deciding factor.
3B21Choose it when the part is bent, formed or impact-loaded, or when the part sees heat.
3005 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.
Yield Strength (0.2% offset)
Elongation at Break
Fatigue Strength (Endurance Limit)
Hardness, Brinell
Same in both: Elastic (Young's) Modulus 69 GPa10 Msi · Shear Modulus 26 GPa3.8 Msi · Bulk Modulus 70 GPa10.2 Msi · Poisson's Ratio 0.33 · Tensile Strength (Ultimate) 175 MPa25.4 ksi · Shear Strength 105 MPa15.2 ksi
Physical
Density and transition temperatures.
Melting Point (Solidus)
Liquidus Temperature
Same in both: Density 2.73 g/cm³0.1 lb/in³
Thermal
How each material carries heat and how hot it can run.
Thermal Conductivity
Thermal Expansion (CTE, 20–100 °C)
Latent Heat of Fusion
Max Service Temperature (continuous)
Min Service Temperature
Same in both: Specific Heat Capacity 893 J/kg·K0.21 BTU/lb·°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
Formability (cold)
Brazeability / Solderability
Polishability
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 200 MJ/kg85,985 BTU/lb · Embodied Carbon (primary production) 12.5 kg CO₂/kg · Embodied Water 1,200 L/kg144 gal/lb · Typical Recycled Content 35%
Common Calculations
Ratios derived from the values above.
Modulus of Resilience
Thermal Diffusivity
Same in both: Specific Strength (UTS / density) 64 kN·m/kg · Specific Stiffness (E / density) 25.3 MN·m/kg · Thermal Shock Resistance Index 17
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 | 3005 | 3B21 |
|---|---|---|
| Sheet metal | Yes | — |
| Default condition | — | — |
| Relative cost | $ Budget | $$ Standard |
| Min. machined wall | — | — |
| Best machined surface | — | — |
| Anodizing Type II | Yes | — |
| Cerakote | Yes | — |
| Chem Film (Alodine) | 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.
3005 vs 3B21 — frequently asked
What is the difference between 3005 and 3B21?
Aluminum 3005 and 3B21 are both aluminum grades. Both yield at about 155 MPa — strength does not separate them. 3B21 is the more ductile: elongation 8% versus 5% for 3005, and 3005 is harder (48 HB vs 44 HB).
Which is cheaper, 3005 or 3B21?
3005 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.
When should I choose 3005 over 3B21?
Pick 3005 when cost is the deciding factor. Pick 3B21 when the part is bent, formed or impact-loaded, or when the part sees heat.
Ready to make it?
Upload a CAD file and FabDigit prices the part in 3005 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.