Aluminum 3203 vs 3A21
Aluminum · grade comparison
Aluminum 3203 and 3A21 are both aluminum grades. Both yield at about 145 MPa — strength does not separate them. On the shop floor, 3203 sits in a lower cost tier (budget, $) than 3A21 (standard, $$).
3203Choose it when cost is the deciding factor.
3203 vs 3A21: 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.
Shear Modulus
Same in both: Elastic (Young's) Modulus 69 GPa10 Msi · Bulk Modulus 69 GPa10 Msi · Poisson's Ratio 0.33 · Tensile Strength (Ultimate) 150 MPa21.8 ksi · Yield Strength (0.2% offset) 145 MPa21 ksi · Elongation at Break 8% · Shear Strength 97 MPa14.1 ksi · Fatigue Strength (Endurance Limit) 62 MPa9 ksi · Hardness, Brinell 40 HB
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.
Min Service Temperature
Same in both: Thermal Conductivity 159 W/m·K91.9 BTU/hr·ft·°F · 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 · Latent Heat of Fusion 390 J/g168 BTU/lb · Max Service Temperature (continuous) 150°C302 °F
Electrical
Conductivity and insulation.
Same in both: Electrical Conductivity 41 % IACS · Electrical Resistivity 4.2×10⁻⁸ Ω·m1.65 µΩ·in
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
Machinability Rating (AISI 1212 = 100 %)
Weldability
Brazeability / Solderability
Same in both: Formability (cold) 70 / 100 · Polishability 45 / 100
Sustainability
Primary-production footprint per kilogram.
Embodied Carbon (primary production)
Embodied Water
Typical Recycled Content
Same in both: Embodied Energy (primary production) 200 MJ/kg85,985 BTU/lb
Common Calculations
Ratios derived from the values above.
Same in both: Specific Strength (UTS / density) 55 kN·m/kg · Specific Stiffness (E / density) 25.3 MN·m/kg · Modulus of Resilience 152 kJ/m³ · Thermal Diffusivity 65.2 mm²/s · Thermal Shock Resistance Index 15
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 | 3203 | 3A21 |
|---|---|---|
| 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.
3203 vs 3A21 — frequently asked
What is the difference between 3203 and 3A21?
Aluminum 3203 and 3A21 are both aluminum grades. Both yield at about 145 MPa — strength does not separate them. On the shop floor, 3203 sits in a lower cost tier (budget, $) than 3A21 (standard, $$).
Which is cheaper, 3203 or 3A21?
3203 is the lower-cost material: it sits in the budget tier ($) while 3A21 is standard ($$). 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, 3203 or 3A21?
3203, by a small margin. Both rate fair for machinability — 45/100 against 40/100 for 3A21.
Ready to make it?
Upload a CAD file and FabDigit prices the part in 3203 and 3A21 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.