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3021 vs FR-2

Composite · grade comparison

3021 and FR-2 are both composite grades. 3021 is the more ductile: elongation 1.5% versus 1.1% for FR-2. 3021 is lighter (1.4 g/cm³ vs 1.55 g/cm³ for FR-2) and 3021 is stiffer (8 GPa vs 7.5 GPa).

3021Choose it when the part is bent, formed or impact-loaded, or when weight is the constraint.

3021 vs FR-2: properties

3021FR-2

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

8 GPa1.2 Msi
7.5 GPa1.1 Msi

Poisson's Ratio

0.3
0.25

Tensile Strength (Ultimate)

90 MPa13.1 ksi
92 MPa13.3 ksi

Elongation at Break

1.5%
1.1%

Compressive Strength

200 MPa29 ksi
250 MPa36.3 ksi

Flexural Strength

120 MPa17.4 ksi
115 MPa16.7 ksi

Flexural Modulus

8.5 GPa1.2 Msi
7.8 GPa1.1 Msi

Izod Impact, Notched

30 J/m0.56 ft·lbf/in
31 J/m0.58 ft·lbf/in

Hardness, Rockwell M

100 HRM
105 HRM

Shear Strength

—
90 MPa13.1 ksi

Fracture Toughness (K_IC)

—
1.7 MPa·√m1.5 ksi·√in

Physical

Density and transition temperatures.

Density

1.4 g/cm³0.05 lb/in³
1.55 g/cm³0.06 lb/in³

Glass Transition (Tg)

150°C302 °F
110°C230 °F

Water Absorption (24 h)

1.5%
0.55%

Water Absorption (Saturation)

4%
2%

Thermal

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

Thermal Conductivity

0.25 W/m·K0.14 BTU/hr·ft·°F
0.35 W/m·K0.2 BTU/hr·ft·°F

Specific Heat Capacity

1,400 J/kg·K0.33 BTU/lb·°F
1,300 J/kg·K0.31 BTU/lb·°F

Thermal Expansion (CTE, 20–100 °C)

25 µm/m·K13.9 µin/in·°F
20 µm/m·K11.1 µin/in·°F

Max Service Temperature (continuous)

120°C248 °F
105°C221 °F

Heat Deflection Temp. @ 1.8 MPa

160°C320 °F
130°C266 °F

Limiting Oxygen Index

28%
30%

Max Service Temperature (short-term)

150°C302 °F
260°C500 °F

Same in both: Min Service Temperature -40°C-40 °F

Electrical

Conductivity and insulation.

Dielectric Strength

12 kV/mm305 V/mil
20 kV/mm508 V/mil

Dielectric Constant (1 MHz)

5
4.6

Dissipation Factor (1 MHz)

0.05
0.04

Same in both: Electrical Resistivity 1×10⁹ Ω·m3.94×10¹⁶ µΩ·in · Volume Resistivity 1×10¹¹ Ω·cm · Surface Resistivity 1×10¹¹ Ω · Comparative Tracking Index (CTI) 125 V

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Corrosion Resistance

60 / 100
48 / 100

UV / Weathering Resistance

35 / 100
25 / 100

Manufacturability

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

Machinability

80 / 100
75 / 100

Polishability

30 / 100
25 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

55 MJ/kg23,646 BTU/lb
85 MJ/kg36,543 BTU/lb

Embodied Carbon (primary production)

3 kg CO₂/kg
4.5 kg CO₂/kg

Embodied Water

—
250 L/kg30 gal/lb

Typical Recycled Content

—
5%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

64 kN·m/kg
59 kN·m/kg

Specific Stiffness (E / density)

5.7 MN·m/kg
4.8 MN·m/kg

Thermal Diffusivity

0.1 mm²/s
0.2 mm²/s

Same in both: Thermal Shock Resistance Index 0

Strength versus weight

Yield strength against density for every composite grade in the FabDigit library; the compared grades are highlighted. Up and left is stronger for its weight.

1101001,000510Density (g/cm³)Yield strength (MPa) — log scale

Manufacturing and finishing

Capability3021FR-2
Default condition——
Relative cost$$ Standard$$ Standard
Min. machined wall——
Best machined surface——

3021 vs FR-2 — frequently asked

What is the difference between 3021 and FR-2?

3021 and FR-2 are both composite grades. 3021 is the more ductile: elongation 1.5% versus 1.1% for FR-2. 3021 is lighter (1.4 g/cm³ vs 1.55 g/cm³ for FR-2) and 3021 is stiffer (8 GPa vs 7.5 GPa).

Which is cheaper, 3021 or FR-2?

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, 3021 or FR-2?

3021, by a small margin. Both rate very good for machinability — 80/100 against 75/100 for FR-2.

Ready to make it?

Upload a CAD file and FabDigit prices the part in 3021 and FR-2 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.