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Steel SK5 vs T8A

Steel · grade comparison

Steel SK5 and T8A are both steel grades. SK5 is the stronger of the two: yield strength 400 MPa (58 ksi) against 375 MPa (54.4 ksi) for T8A, about 7% more; tensile strength follows at 710 MPa (103 ksi) vs 620 MPa (89.9 ksi). In exchange, T8A is the more ductile: elongation 24% versus 12% for SK5, and SK5 is harder (200 HB vs 179 HB). SK5 runs hotter in service (350°C vs 300°C continuous). On the shop floor, T8A machines more easily (good vs fair) and T8A sits in a lower cost tier (budget, $) than SK5 (standard, $$).

SK5Choose 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.

SK5 vs T8A: properties

SK5T8A

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

205 GPa29.7 Msi
210 GPa30.5 Msi

Tensile Strength (Ultimate)

710 MPa103 ksi
620 MPa89.9 ksi

Yield Strength (0.2% offset)

400 MPa58 ksi
375 MPa54.4 ksi

Elongation at Break

12%
24%

Reduction in Area

20%
45%

Compressive Strength

720 MPa104 ksi
400 MPa58 ksi

Shear Strength

460 MPa66.7 ksi
400 MPa58 ksi

Fatigue Strength (Endurance Limit)

320 MPa46.4 ksi
290 MPa42.1 ksi

Fracture Toughness (K_IC)

45 MPa·√m41 ksi·√in
—

Charpy V-Notch Impact (RT)

10 J7.4 ft·lbf
12 J8.9 ft·lbf

Hardness, Brinell

200 HB
179 HB

Hardness, Rockwell B

93 HRB
89 HRB

Hardness, Vickers

210 HV
188 HV

Same in both: Shear Modulus 80 GPa11.6 Msi · Bulk Modulus 160 GPa23.2 Msi · Poisson's Ratio 0.29

Physical

Density and transition temperatures.

Density

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

Melting Point (Solidus)

1,425°C2,597 °F
1,400°C2,552 °F

Same in both: Liquidus Temperature 1,470°C2,678 °F

Thermal

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

Specific Heat Capacity

475 J/kg·K0.11 BTU/lb·°F
470 J/kg·K0.11 BTU/lb·°F

Max Service Temperature (continuous)

350°C662 °F
300°C572 °F

Same in both: Thermal Conductivity 48 W/m·K27.7 BTU/hr·ft·°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 · 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

36 / 100
58 / 100

Machinability Rating (AISI 1212 = 100 %)

40%
65%

Formability (cold)

30 / 100
40 / 100

Castability

30 / 100
—

Polishability

70 / 100
60 / 100

Same in both: Weldability 18 / 100 · Brazeability / Solderability 45 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

27 MJ/kg11,608 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

Typical Recycled Content

30%
25%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

91 kN·m/kg
79 kN·m/kg

Specific Stiffness (E / density)

26.2 MN·m/kg
26.8 MN·m/kg

Modulus of Resilience

390 kJ/m³
335 kJ/m³

Thermal Diffusivity

12.9 mm²/s
13 mm²/s

Thermal Shock Resistance Index

14
12

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 scaleSK5T8A

Manufacturing and finishing

CapabilitySK5T8A
CNC machiningYes—
Sheet metalYes—
Default conditionHR—
Relative cost$$ Standard$ Budget
Min. machined wall0.8 mm—
Best machined surfaceRa 1.6 µm—
AlCrNYes—
AlTiNYes—
Black OxideYes—
CVD Al2O3Yes—
CVD TiCNYes—
CVD TiNYes—
CerakoteYes—
Chrome PlatingYes—
CrNYes—
DLCYes—
E-CoatingYes—
HVOF CoatingYes—
Hot-Dip GalvanizingYes—
MoS2Yes—
Multilayer CVDYes—
Nickel PlatingYes—
PTFE CoatingYes—
PaintingYes—

They share 9 finishes: Copper Plating, Electroless Nickel (EN), Epoxy Coating, Gold Plating, Hard Chrome Plating, Manganese Phosphate, Plasma Spray, Silver Plating, Zinc Phosphate.

SK5 vs T8A — frequently asked

Is SK5 stronger than T8A?

Yes. SK5 has a typical yield strength of 400 MPa (58 ksi) against 375 MPa (54.4 ksi) for T8A — about 7% more. Tensile strength is 710 MPa (103 ksi) vs 620 MPa (89.9 ksi).

Which is cheaper, SK5 or T8A?

T8A is the lower-cost material: it sits in the budget tier ($) while SK5 is standard ($$). Part price depends far more on geometry, tolerance and quantity than on raw stock — upload a CAD file for a live quote.

Which is easier to machine, SK5 or T8A?

T8A. Its machinability rates good (58/100) against fair (36/100) for SK5.

Ready to make it?

Upload a CAD file and FabDigit prices the part in SK5 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.