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Aluminum AC3A vs AC4CH

Aluminum · grade comparison

Aluminum AC3A and AC4CH are both aluminum grades. AC4CH is the stronger of the two: yield strength 210 MPa (30.5 ksi) against 75 MPa (10.9 ksi) for AC3A, about 180% more; tensile strength follows at 280 MPa (40.6 ksi) vs 165 MPa (23.9 ksi). AC4CH is the more ductile: elongation 8% versus 6% for AC3A, and AC4CH is harder (85 HB vs 50 HB). AC4CH conducts heat better (151 W/m·K vs 130 W/m·K). On the shop floor, AC4CH machines more easily (good vs fair).

AC4CHChoose it when strength drives the design, or when the part is bent, formed or impact-loaded.

AC3A vs AC4CH: properties

AC3AAC4CH

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

71 GPa10.3 Msi
72.4 GPa10.5 Msi

Shear Modulus

26.5 GPa3.8 Msi
27 GPa3.9 Msi

Bulk Modulus

70 GPa10.2 Msi
71 GPa10.3 Msi

Tensile Strength (Ultimate)

165 MPa23.9 ksi
280 MPa40.6 ksi

Yield Strength (0.2% offset)

75 MPa10.9 ksi
210 MPa30.5 ksi

Elongation at Break

6%
8%

Shear Strength

115 MPa16.7 ksi
200 MPa29 ksi

Fatigue Strength (Endurance Limit)

55 MPa8 ksi
90 MPa13.1 ksi

Fracture Toughness (K_IC)

15 MPa·√m13.7 ksi·√in
25 MPa·√m22.8 ksi·√in

Charpy V-Notch Impact (RT)

3 J2.2 ft·lbf
4 J3 ft·lbf

Hardness, Brinell

50 HB
85 HB

Compressive Strength

—
215 MPa31.2 ksi

Same in both: Poisson's Ratio 0.33

Physical

Density and transition temperatures.

Density

2.66 g/cm³0.1 lb/in³
2.68 g/cm³0.1 lb/in³

Melting Point (Solidus)

574°C1,065 °F
557°C1,035 °F

Liquidus Temperature

582°C1,080 °F
613°C1,135 °F

Thermal

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

Thermal Conductivity

130 W/m·K75.1 BTU/hr·ft·°F
151 W/m·K87.2 BTU/hr·ft·°F

Thermal Expansion (CTE, 20–100 °C)

20.5 µm/m·K11.4 µin/in·°F
21.5 µm/m·K11.9 µin/in·°F

Same in both: Specific Heat Capacity 963 J/kg·K0.23 BTU/lb·°F · Latent Heat of Fusion 389 J/g167 BTU/lb · Max Service Temperature (continuous) 150°C302 °F · Min Service Temperature -196°C-321 °F

Electrical

Conductivity and insulation.

Electrical Conductivity

33 % IACS
39 % IACS

Electrical Resistivity

5.2×10⁻⁸ Ω·m2.05 µΩ·in
4.4×10⁻⁸ Ω·m1.73 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Corrosion Resistance

58 / 100
55 / 100

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

40 / 100
60 / 100

Machinability Rating (AISI 1212 = 100 %)

30%
70%

Weldability

80 / 100
75 / 100

Formability (cold)

10 / 100
15 / 100

Castability

95 / 100
92 / 100

Brazeability / Solderability

35 / 100
30 / 100

Polishability

45 / 100
55 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Carbon (primary production)

12 kg CO₂/kg
12.5 kg CO₂/kg

Embodied Water

1,200 L/kg144 gal/lb
1,100 L/kg132 gal/lb

Typical Recycled Content

70%
20%

Same in both: Embodied Energy (primary production) 200 MJ/kg85,985 BTU/lb

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

62 kN·m/kg
104 kN·m/kg

Specific Stiffness (E / density)

26.7 MN·m/kg
27 MN·m/kg

Modulus of Resilience

40 kJ/m³
305 kJ/m³

Thermal Diffusivity

50.7 mm²/s
58.5 mm²/s

Thermal Shock Resistance Index

15
27

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.

20501002005002.22.42.62.83Density (g/cm³)Yield strength (MPa) — log scaleAC3AAC4CH

Manufacturing and finishing

CapabilityAC3AAC4CH
Default condition——
Relative cost$$ Standard$$ Standard
Min. machined wall——
Best machined surface——

Both take the same 4 finishes: Electroless Nickel (EN), Epoxy Coating, Gold Plating, Silver Plating.

AC3A vs AC4CH — frequently asked

Is AC4CH stronger than AC3A?

Yes. AC4CH has a typical yield strength of 210 MPa (30.5 ksi) against 75 MPa (10.9 ksi) for AC3A — about 180% more. Tensile strength is 280 MPa (40.6 ksi) vs 165 MPa (23.9 ksi).

Which is cheaper, AC3A or AC4CH?

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 is easier to machine, AC3A or AC4CH?

AC4CH. Its machinability rates good (60/100) against fair (40/100) for AC3A; for welding the order is AC3A first (very good, 80/100) then AC4CH (very good, 75/100).

Ready to make it?

Upload a CAD file and FabDigit prices the part in AC3A and AC4CH 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.