Magnesium Alloy EV31A vs QE21
Magnesium Alloy · grade comparison
Magnesium Alloy EV31A and QE21 are both magnesium alloy grades. QE21 is the stronger of the two: yield strength 175 MPa (25.4 ksi) against 110 MPa (16 ksi) for EV31A, about 59% more; tensile strength follows at 240 MPa (34.8 ksi) vs 195 MPa (28.3 ksi). In exchange, EV31A is the more ductile: elongation 4% versus 3% for QE21, and QE21 is harder (75 HB vs 55 HB). QE21 runs hotter in service (200°C vs 150°C continuous) and QE21 conducts heat better (113 W/m·K vs 100 W/m·K). On the shop floor, EV31A sits in a lower cost tier (standard, $$) than QE21 (high, $$$$).
EV31AChoose it when the part is bent, formed or impact-loaded, or when cost is the deciding factor.
QE21Choose it when strength drives the design, or when the part sees heat.
EV31A vs QE21: propertiesHow to read these bars
- One bar per material. A full bar is the highest value among all magnesium alloy 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 magnesium alloy 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
Bulk Modulus
Poisson's Ratio
Tensile Strength (Ultimate)
Yield Strength (0.2% offset)
Elongation at Break
Compressive Strength
Shear Strength
Fatigue Strength (Endurance Limit)
Fracture Toughness (K_IC)
Hardness, Brinell
Hardness, Vickers
Same in both: Elastic (Young's) Modulus 44 GPa6.4 Msi · Charpy V-Notch Impact (RT) 3 J2.2 ft·lbf
Physical
Density and transition temperatures.
Density
Same in both: Melting Point (Solidus) 545°C1,013 °F · Liquidus Temperature 640°C1,184 °F
Thermal
How each material carries heat and how hot it can run.
Thermal Conductivity
Max Service Temperature (continuous)
Min Service Temperature
Same in both: Specific Heat Capacity 1,000 J/kg·K0.24 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 26.7 µm/m·K14.8 µin/in·°F · Latent Heat of Fusion 370 J/g159 BTU/lb
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) -1.55 V
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Weldability
Castability
Polishability
Same in both: Machinability Rating (AISI 1212 = 100 %) 300% · Formability (cold) 10 / 100 · Brazeability / Solderability 20 / 100
Sustainability
Primary-production footprint per kilogram.
Embodied Energy (primary production)
Embodied Carbon (primary production)
Embodied Water
Typical Recycled Content
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 magnesium alloy grade in the FabDigit library; the compared grades are highlighted. Up and left is stronger for its weight.
Manufacturing and finishing
| Capability | EV31A | QE21 |
|---|---|---|
| CNC machining | Yes | — |
| Default condition | As Cast | — |
| Relative cost | $$ Standard | $$$$ High |
| Min. machined wall | 0.8 mm | — |
| Best machined surface | Ra 0.8 µm | — |
| Anodizing Type II | Yes | — |
| Chem Film (Alodine) | Yes | — |
| E-Coating | Yes | — |
| Hard Anodize Type III w/ PTFE | Yes | — |
| Hard Anodizing Type III | Yes | — |
| Painting | Yes | — |
| Powder Coating | Yes | — |
EV31A vs QE21 — frequently asked
Is QE21 stronger than EV31A?
Yes. QE21 has a typical yield strength of 175 MPa (25.4 ksi) against 110 MPa (16 ksi) for EV31A — about 59% more. Tensile strength is 240 MPa (34.8 ksi) vs 195 MPa (28.3 ksi).
Which is cheaper, EV31A or QE21?
EV31A is the lower-cost material: it sits in the standard tier ($$) while QE21 is high ($$$$). 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 EV31A over QE21?
Pick EV31A when the part is bent, formed or impact-loaded, or when cost is the deciding factor. Pick QE21 when strength drives the design, or when the part sees heat.
Ready to make it?
Upload a CAD file and FabDigit prices the part in EV31A and QE21 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.