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Steel T12A vs T8A

Steel · grade comparison

Steel T12A and T8A are both steel grades. T12A is the stronger of the two: yield strength 420 MPa (60.9 ksi) against 375 MPa (54.4 ksi) for T8A, about 12% more; tensile strength follows at 720 MPa (104 ksi) vs 620 MPa (89.9 ksi). In exchange, T8A is the more ductile: elongation 24% versus 20% for T12A, and T12A is harder (200 HB vs 179 HB). T12A runs hotter in service (400°C vs 300°C continuous). On the shop floor, T8A machines more easily (good vs fair).

T12AChoose it when strength drives the design, or when the part sees heat.

T8AChoose it when the part is bent, formed or impact-loaded, or when the part is machined in volume.

T12A vs T8A: properties

T12AT8A

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Shear Modulus

81 GPa11.7 Msi
80 GPa11.6 Msi

Bulk Modulus

165 GPa23.9 Msi
160 GPa23.2 Msi

Tensile Strength (Ultimate)

720 MPa104 ksi
620 MPa89.9 ksi

Yield Strength (0.2% offset)

420 MPa60.9 ksi
375 MPa54.4 ksi

Elongation at Break

20%
24%

Reduction in Area

40%
45%

Compressive Strength

430 MPa62.4 ksi
400 MPa58 ksi

Shear Strength

450 MPa65.3 ksi
400 MPa58 ksi

Fatigue Strength (Endurance Limit)

320 MPa46.4 ksi
290 MPa42.1 ksi

Fracture Toughness (K_IC)

50 MPa·√m45.5 ksi·√in
—

Hardness, Brinell

200 HB
179 HB

Hardness, Rockwell B

93 HRB
89 HRB

Hardness, Vickers

210 HV
188 HV

Same in both: Elastic (Young's) Modulus 210 GPa30.5 Msi · Poisson's Ratio 0.29 · Charpy V-Notch Impact (RT) 12 J8.9 ft·lbf

Physical

Density and transition temperatures.

Melting Point (Solidus)

1,300°C2,372 °F
1,400°C2,552 °F

Liquidus Temperature

1,440°C2,624 °F
1,470°C2,678 °F

Same in both: Density 7.85 g/cm³0.28 lb/in³

Thermal

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

Thermal Conductivity

47 W/m·K27.2 BTU/hr·ft·°F
48 W/m·K27.7 BTU/hr·ft·°F

Thermal Expansion (CTE, 20–100 °C)

11.8 µm/m·K6.6 µin/in·°F
11.5 µm/m·K6.4 µin/in·°F

Max Service Temperature (continuous)

400°C752 °F
300°C572 °F

Same in both: Specific Heat Capacity 470 J/kg·K0.11 BTU/lb·°F · Latent Heat of Fusion 250 J/g107 BTU/lb · 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)

-0.62 V
-0.6 V

Corrosion Resistance

9 / 100
10 / 100

Manufacturability

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

Machinability

45 / 100
58 / 100

Machinability Rating (AISI 1212 = 100 %)

45%
65%

Weldability

12 / 100
18 / 100

Brazeability / Solderability

50 / 100
45 / 100

Polishability

70 / 100
60 / 100

Same in both: Formability (cold) 40 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

28 MJ/kg12,038 BTU/lb
30 MJ/kg12,898 BTU/lb

Embodied Carbon (primary production)

2.1 kg CO₂/kg
2.2 kg CO₂/kg

Typical Recycled Content

30%
25%

Same in both: Embodied Water 60 L/kg7.2 gal/lb

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

92 kN·m/kg
79 kN·m/kg

Modulus of Resilience

420 kJ/m³
335 kJ/m³

Thermal Diffusivity

12.7 mm²/s
13 mm²/s

Thermal Shock Resistance Index

14
12

Same in both: Specific Stiffness (E / density) 26.8 MN·m/kg

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 scaleT12AT8A

Manufacturing and finishing

CapabilityT12AT8A
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.

T12A vs T8A — frequently asked

Is T12A stronger than T8A?

Yes. T12A has a typical yield strength of 420 MPa (60.9 ksi) against 375 MPa (54.4 ksi) for T8A — about 12% more. Tensile strength is 720 MPa (104 ksi) vs 620 MPa (89.9 ksi).

Which is cheaper, T12A 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.

Which is easier to machine, T12A or T8A?

T8A. Its machinability rates good (58/100) against fair (45/100) for T12A; for welding the order is T8A first (poor, 18/100) then T12A (not recommended, 12/100).

Ready to make it?

Upload a CAD file and FabDigit prices the part in T12A 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.