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Magnesium Alloy AZ80A vs HK31A

Magnesium Alloy · grade comparison

Magnesium Alloy AZ80A and HK31A are both magnesium alloy grades. AZ80A is the stronger of the two: yield strength 250 MPa (36.3 ksi) against 200 MPa (29 ksi) for HK31A, about 25% more; tensile strength follows at 340 MPa (49.3 ksi) vs 255 MPa (37 ksi). AZ80A is the more ductile: elongation 11% versus 9% for HK31A, and AZ80A is harder (60 HB vs 57 HB). HK31A runs hotter in service (315°C vs 120°C continuous) and HK31A conducts heat better (111 W/m·K vs 78 W/m·K). On the shop floor, HK31A welds better (very good vs fair).

AZ80AChoose it when strength drives the design, or when the part is bent, formed or impact-loaded.

HK31AChoose it when the part sees heat, or when it will be welded.

AZ80A vs HK31A: properties

AZ80AHK31A

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Tensile Strength (Ultimate)

340 MPa49.3 ksi
255 MPa37 ksi

Yield Strength (0.2% offset)

250 MPa36.3 ksi
200 MPa29 ksi

Elongation at Break

11%
9%

Compressive Strength

240 MPa34.8 ksi
170 MPa24.7 ksi

Shear Strength

165 MPa23.9 ksi
150 MPa21.8 ksi

Fatigue Strength (Endurance Limit)

138 MPa20 ksi
83 MPa12 ksi

Fracture Toughness (K_IC)

15 MPa·√m13.7 ksi·√in
—

Charpy V-Notch Impact (RT)

4 J3 ft·lbf
—

Hardness, Brinell

60 HB
57 HB

Hardness, Vickers

68 HV
—

Same in both: Elastic (Young's) Modulus 45 GPa6.5 Msi · Shear Modulus 17 GPa2.5 Msi · Bulk Modulus 45 GPa6.5 Msi · Poisson's Ratio 0.35

Physical

Density and transition temperatures.

Density

1.8 g/cm³0.07 lb/in³
1.79 g/cm³0.06 lb/in³

Melting Point (Solidus)

490°C914 °F
588°C1,090 °F

Liquidus Temperature

610°C1,130 °F
650°C1,202 °F

Thermal

How each material carries heat and how hot it can run.

Thermal Conductivity

78 W/m·K45.1 BTU/hr·ft·°F
111 W/m·K64.1 BTU/hr·ft·°F

Specific Heat Capacity

1,000 J/kg·K0.24 BTU/lb·°F
1,005 J/kg·K0.24 BTU/lb·°F

Thermal Expansion (CTE, 20–100 °C)

26 µm/m·K14.4 µin/in·°F
26.1 µm/m·K14.5 µin/in·°F

Latent Heat of Fusion

370 J/g159 BTU/lb
340 J/g146 BTU/lb

Max Service Temperature (continuous)

120°C248 °F
315°C599 °F

Min Service Temperature

-70°C-94 °F
-100°C-148 °F

Electrical

Conductivity and insulation.

Electrical Conductivity

11.5 % IACS
28 % IACS

Electrical Resistivity

1.5×10⁻⁷ Ω·m5.91 µΩ·in
6.2×10⁻⁸ Ω·m2.44 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Galvanic Potential (seawater, vs SCE)

-1.58 V
-1.55 V

Same in both: Corrosion Resistance 20 / 100

Manufacturability

FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.

Machinability

98 / 100
95 / 100

Machinability Rating (AISI 1212 = 100 %)

500%
400%

Weldability

45 / 100
70 / 100

Formability (cold)

18 / 100
35 / 100

Brazeability / Solderability

20 / 100
25 / 100

Polishability

55 / 100
50 / 100

Castability

—
75 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

330 MJ/kg141,875 BTU/lb
350 MJ/kg150,473 BTU/lb

Embodied Carbon (primary production)

27 kg CO₂/kg
32 kg CO₂/kg

Typical Recycled Content

20%
5%

Same in both: Embodied Water 500 L/kg59.9 gal/lb

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

189 kN·m/kg
142 kN·m/kg

Specific Stiffness (E / density)

25 MN·m/kg
25.1 MN·m/kg

Modulus of Resilience

694 kJ/m³
444 kJ/m³

Thermal Diffusivity

43.3 mm²/s
61.7 mm²/s

Thermal Shock Resistance Index

23
24

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.

701001502001.41.51.61.71.8Density (g/cm³)Yield strength (MPa) — log scaleAZ80AHK31A

Manufacturing and finishing

CapabilityAZ80AHK31A
Default conditionFH24
Relative cost$$ Standard$$ Standard
Min. machined wall0.8 mm0.8 mm
Best machined surfaceRa 0.8 µmRa 0.8 µm

Both are offered for CNC machining and Sheet metal. Both take the same 7 finishes: Anodizing Type II, Chem Film (Alodine), E-Coating, Hard Anodize Type III w/ PTFE, Hard Anodizing Type III, Painting, Powder Coating.

AZ80A vs HK31A — frequently asked

Is AZ80A stronger than HK31A?

Yes. AZ80A has a typical yield strength of 250 MPa (36.3 ksi) against 200 MPa (29 ksi) for HK31A — about 25% more. Tensile strength is 340 MPa (49.3 ksi) vs 255 MPa (37 ksi).

Which is cheaper, AZ80A or HK31A?

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, AZ80A or HK31A?

HK31A. Its weldability rates very good (70/100) against fair (45/100) for AZ80A.

Ready to make it?

Upload a CAD file and FabDigit prices the part in AZ80A and HK31A 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.