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Steel T7A vs T8A

Steel · grade comparison

Steel T7A and T8A are both steel grades. T7A is the stronger of the two: tensile strength 660 MPa (95.7 ksi) against 620 MPa (89.9 ksi) for T8A, about 6% more.

T7AChoose it when strength drives the design.

T7A vs T8A: properties

T7AT8A

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

207 GPa30 Msi
210 GPa30.5 Msi

Tensile Strength (Ultimate)

660 MPa95.7 ksi
620 MPa89.9 ksi

Yield Strength (0.2% offset)

380 MPa55.1 ksi
375 MPa54.4 ksi

Elongation at Break

22%
24%

Reduction in Area

40%
45%

Shear Strength

430 MPa62.4 ksi
400 MPa58 ksi

Fatigue Strength (Endurance Limit)

300 MPa43.5 ksi
290 MPa42.1 ksi

Charpy V-Notch Impact (RT)

40 J29.5 ft·lbf
12 J8.9 ft·lbf

Hardness, Brinell

180 HB
179 HB

Hardness, Vickers

190 HV
188 HV

Same in both: Shear Modulus 80 GPa11.6 Msi · Bulk Modulus 160 GPa23.2 Msi · Poisson's Ratio 0.29 · Compressive Strength 400 MPa58 ksi · Hardness, Rockwell B 89 HRB

Physical

Density and transition temperatures.

Density

7.83 g/cm³0.28 lb/in³
7.85 g/cm³0.28 lb/in³

Melting Point (Solidus)

1,420°C2,588 °F
1,400°C2,552 °F

Liquidus Temperature

1,480°C2,696 °F
1,470°C2,678 °F

Thermal

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

Same in both: Thermal Conductivity 48 W/m·K27.7 BTU/hr·ft·°F · Specific Heat Capacity 470 J/kg·K0.11 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 11.5 µm/m·K6.4 µin/in·°F · Latent Heat of Fusion 250 J/g107 BTU/lb · Max Service Temperature (continuous) 300°C572 °F · Min Service Temperature -20°C-4 °F

Electrical

Conductivity and insulation.

Same in both: Electrical Conductivity 9.5 % IACS · Electrical Resistivity 1.8×10⁻⁷ Ω·m7.09 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Galvanic Potential (seawater, vs SCE)

-0.61 V
-0.6 V

Same in both: Corrosion Resistance 10 / 100

Manufacturability

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

Machinability

62 / 100
58 / 100

Weldability

20 / 100
18 / 100

Formability (cold)

45 / 100
40 / 100

Castability

30 / 100
—

Brazeability / Solderability

55 / 100
45 / 100

Polishability

70 / 100
60 / 100

Same in both: Machinability Rating (AISI 1212 = 100 %) 65%

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

26 MJ/kg11,178 BTU/lb
30 MJ/kg12,898 BTU/lb

Embodied Carbon (primary production)

2.1 kg CO₂/kg
2.2 kg CO₂/kg

Embodied Water

45 L/kg5.4 gal/lb
60 L/kg7.2 gal/lb

Same in both: Typical Recycled Content 25%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

84 kN·m/kg
79 kN·m/kg

Specific Stiffness (E / density)

26.4 MN·m/kg
26.8 MN·m/kg

Modulus of Resilience

349 kJ/m³
335 kJ/m³

Thermal Shock Resistance Index

13
12

Same in both: Thermal Diffusivity 13 mm²/s

Strength versus weight

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

2005001,0002,0007.588.5Density (g/cm³)Yield strength (MPa) — log scaleT7AT8A

Manufacturing and finishing

CapabilityT7AT8A
Default condition——
Relative cost$ Budget$ Budget
Min. machined wall——
Best machined surface——

Both take the same 9 finishes: Copper Plating, Electroless Nickel (EN), Epoxy Coating, Gold Plating, Hard Chrome Plating, Manganese Phosphate, Plasma Spray, Silver Plating, Zinc Phosphate.

T7A vs T8A — frequently asked

Is T7A stronger than T8A?

Yes. T7A has a typical tensile strength of 660 MPa (95.7 ksi) against 620 MPa (89.9 ksi) for T8A — about 6% more.

Which is cheaper, T7A or T8A?

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

When should I choose T7A over T8A?

Pick T7A when strength drives the design.

Ready to make it?

Upload a CAD file and FabDigit prices the part in T7A and T8A 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.