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M55J vs T800H

Composite · grade comparison

M55J and T800H are both composite grades. T800H is the stronger of the two: tensile strength 5,490 MPa (796 ksi) against 4,020 MPa (583 ksi) for M55J, about 37% more. T800H is the more ductile: elongation 1.9% versus 0.8% for M55J. T800H is lighter (1.81 g/cm³ vs 1.91 g/cm³ for M55J) and M55J is stiffer (540 GPa vs 294 GPa).

T800HChoose it when strength drives the design, or when the part is bent, formed or impact-loaded.

M55J vs T800H: properties

M55JT800H

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

540 GPa78.3 Msi
294 GPa42.6 Msi

Tensile Strength (Ultimate)

4,020 MPa583 ksi
5,490 MPa796 ksi

Elongation at Break

0.8%
1.9%

Compressive Strength

900 MPa131 ksi
2,400 MPa348 ksi

Physical

Density and transition temperatures.

Density

1.91 g/cm³0.07 lb/in³
1.81 g/cm³0.07 lb/in³

Water Absorption (24 h)

0.1%
—

Thermal

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

Thermal Conductivity

155 W/m·K89.6 BTU/hr·ft·°F
35 W/m·K20.2 BTU/hr·ft·°F

Specific Heat Capacity

753 J/kg·K0.18 BTU/lb·°F
750 J/kg·K0.18 BTU/lb·°F

Thermal Expansion (CTE, 20–100 °C)

-1.1 µm/m·K-0.61 µin/in·°F
-0.56 µm/m·K-0.31 µin/in·°F

Same in both: Max Service Temperature (continuous) 400°C752 °F · Min Service Temperature -269°C-452 °F · Max Service Temperature (short-term) 500°C932 °F

Electrical

Conductivity and insulation.

Electrical Resistivity

8×10⁻⁶ Ω·m315 µΩ·in
1.4×10⁻⁵ Ω·m551 µΩ·in

Volume Resistivity

8×10⁻⁴ Ω·cm
—

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

UV / Weathering Resistance

90 / 100
85 / 100

Same in both: Corrosion Resistance 92 / 100

Manufacturability

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

Same in both: Machinability 18 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

750 MJ/kg322,442 BTU/lb
500 MJ/kg214,962 BTU/lb

Embodied Carbon (primary production)

50 kg CO₂/kg
34 kg CO₂/kg

Embodied Water

700 L/kg83.9 gal/lb
600 L/kg71.9 gal/lb

Same in both: Typical Recycled Content 0%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

2,105 kN·m/kg
3,033 kN·m/kg

Specific Stiffness (E / density)

282.7 MN·m/kg
162.4 MN·m/kg

Thermal Diffusivity

107.8 mm²/s
25.8 mm²/s

Thermal Shock Resistance Index

-1,049
-1,167

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

CapabilityM55JT800H
Default condition——
Relative cost$$$$ High$$$$ High
Min. machined wall——
Best machined surface——

M55J vs T800H — frequently asked

Is T800H stronger than M55J?

Yes. T800H has a typical tensile strength of 5,490 MPa (796 ksi) against 4,020 MPa (583 ksi) for M55J — about 37% more.

Which is cheaper, M55J or T800H?

Both sit in the same relative cost tier ($$$$, high); the part price will be decided by machining time, tolerance and quantity rather than by the material.

When should I choose M55J over T800H?

Pick T800H when strength drives the design, or when the part is bent, formed or impact-loaded.

Ready to make it?

Upload a CAD file and FabDigit prices the part in M55J and T800H 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.