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Aluminum AC2B vs AC4A

Aluminum · grade comparison

Aluminum AC2B and AC4A are both aluminum grades. AC4A is the stronger of the two: yield strength 200 MPa (29 ksi) against 110 MPa (16 ksi) for AC2B, about 82% more; tensile strength follows at 260 MPa (37.7 ksi) vs 180 MPa (26.1 ksi). AC4A is the more ductile: elongation 3% versus 2% for AC2B, and AC4A is harder (90 HB vs 70 HB). AC4A is lighter (2.68 g/cm³ vs 2.77 g/cm³ for AC2B) and AC4A conducts heat better (150 W/m·K vs 109 W/m·K). On the shop floor, AC2B machines more easily (good vs fair) and AC4A welds better (good vs fair).

AC2BChoose it when the part is machined in volume.

AC4AChoose it when strength drives the design, or when the part is bent, formed or impact-loaded.

AC2B vs AC4A: properties

AC2BAC4A

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

74 GPa10.7 Msi
71 GPa10.3 Msi

Shear Modulus

28 GPa4.1 Msi
26.5 GPa3.8 Msi

Bulk Modulus

71 GPa10.3 Msi
70 GPa10.2 Msi

Tensile Strength (Ultimate)

180 MPa26.1 ksi
260 MPa37.7 ksi

Yield Strength (0.2% offset)

110 MPa16 ksi
200 MPa29 ksi

Elongation at Break

2%
3%

Compressive Strength

115 MPa16.7 ksi
205 MPa29.7 ksi

Shear Strength

145 MPa21 ksi
180 MPa26.1 ksi

Fatigue Strength (Endurance Limit)

70 MPa10.2 ksi
90 MPa13.1 ksi

Fracture Toughness (K_IC)

17 MPa·√m15.5 ksi·√in
18 MPa·√m16.4 ksi·√in

Hardness, Brinell

70 HB
90 HB

Same in both: Poisson's Ratio 0.33 · Charpy V-Notch Impact (RT) 4 J3 ft·lbf

Physical

Density and transition temperatures.

Density

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

Melting Point (Solidus)

516°C961 °F
557°C1,035 °F

Liquidus Temperature

604°C1,119 °F
596°C1,105 °F

Thermal

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

Thermal Conductivity

109 W/m·K63 BTU/hr·ft·°F
150 W/m·K86.7 BTU/hr·ft·°F

Latent Heat of Fusion

389 J/g167 BTU/lb
425 J/g183 BTU/lb

Same in both: Specific Heat Capacity 963 J/kg·K0.23 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 21.5 µm/m·K11.9 µin/in·°F · Max Service Temperature (continuous) 150°C302 °F · Min Service Temperature -196°C-321 °F

Electrical

Conductivity and insulation.

Electrical Conductivity

27 % IACS
39 % IACS

Electrical Resistivity

6.4×10⁻⁸ Ω·m2.52 µΩ·in
4.4×10⁻⁸ Ω·m1.73 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Galvanic Potential (seawater, vs SCE)

-0.81 V
-0.83 V

Corrosion Resistance

42 / 100
58 / 100

Manufacturability

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

Machinability

65 / 100
50 / 100

Machinability Rating (AISI 1212 = 100 %)

130%
60%

Weldability

35 / 100
65 / 100

Formability (cold)

5 / 100
10 / 100

Castability

85 / 100
88 / 100

Brazeability / Solderability

20 / 100
25 / 100

Polishability

40 / 100
45 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

200 MJ/kg85,985 BTU/lb
155 MJ/kg66,638 BTU/lb

Embodied Carbon (primary production)

12 kg CO₂/kg
9.5 kg CO₂/kg

Embodied Water

1,150 L/kg138 gal/lb
1,100 L/kg132 gal/lb

Typical Recycled Content

85%
70%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

65 kN·m/kg
97 kN·m/kg

Specific Stiffness (E / density)

26.7 MN·m/kg
26.5 MN·m/kg

Modulus of Resilience

82 kJ/m³
282 kJ/m³

Thermal Diffusivity

40.9 mm²/s
58.1 mm²/s

Thermal Shock Resistance Index

12
26

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 scaleAC2BAC4A

Manufacturing and finishing

CapabilityAC2BAC4A
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.

AC2B vs AC4A — frequently asked

Is AC4A stronger than AC2B?

Yes. AC4A has a typical yield strength of 200 MPa (29 ksi) against 110 MPa (16 ksi) for AC2B — about 82% more. Tensile strength is 260 MPa (37.7 ksi) vs 180 MPa (26.1 ksi).

Which is cheaper, AC2B or AC4A?

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, AC2B or AC4A?

AC2B. Its machinability rates good (65/100) against fair (50/100) for AC4A; for welding the order is AC4A first (good, 65/100) then AC2B (fair, 35/100).

Ready to make it?

Upload a CAD file and FabDigit prices the part in AC2B and AC4A 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.