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Steel SK95-N vs SK95-QT400

Steel · SK95 temper comparison

SK95-N and SK95-QT400 are two conditions of the same steel grade, SK95: N (normalized) versus QT400 (quenched + tempered 400 °C). The chemistry is identical, so every difference below comes from the condition. SK95-QT400 is the stronger of the two: yield strength 1,300 MPa (189 ksi) against 520 MPa (75.4 ksi) for SK95-N, about 150% more; tensile strength follows at 1,500 MPa (218 ksi) vs 900 MPa (131 ksi). In exchange, SK95-N is the more ductile: elongation 10% versus 6% for SK95-QT400, and SK95-QT400 is harder (445 HB vs 270 HB). SK95-N runs hotter in service (400°C vs 320°C continuous). On the shop floor, SK95-N machines more easily (fair vs poor).

SK95-NChoose it when the part is bent, formed or impact-loaded, or when the part sees heat.

SK95-QT400Choose it when strength drives the design.

SK95-N vs SK95-QT400: properties

SK95-NSK95-QT400

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Tensile Strength (Ultimate)

900 MPa131 ksi
1,500 MPa218 ksi

Yield Strength (0.2% offset)

520 MPa75.4 ksi
1,300 MPa189 ksi

Elongation at Break

10%
6%

Reduction in Area

24%
15%

Compressive Strength

545 MPa79 ksi
1,900 MPa276 ksi

Shear Strength

560 MPa81.2 ksi
900 MPa131 ksi

Fatigue Strength (Endurance Limit)

400 MPa58 ksi
560 MPa81.2 ksi

Charpy V-Notch Impact (RT)

10 J7.4 ft·lbf
18 J13.3 ft·lbf

Hardness, Brinell

270 HB
445 HB

Hardness, Vickers

285 HV
470 HV

Same in both: Elastic (Young's) Modulus 205 GPa29.7 Msi · Shear Modulus 80 GPa11.6 Msi · Bulk Modulus 160 GPa23.2 Msi · Poisson's Ratio 0.29 · Hardness, Rockwell B 91 HRB

Physical

Density and transition temperatures.

Same in both: Density 7.83 g/cm³0.28 lb/in³ · Melting Point (Solidus) 1,420°C2,588 °F · Liquidus Temperature 1,480°C2,696 °F

Thermal

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

Thermal Conductivity

46 W/m·K26.6 BTU/hr·ft·°F
43 W/m·K24.8 BTU/hr·ft·°F

Max Service Temperature (continuous)

400°C752 °F
320°C608 °F

Same in both: 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 · Min Service Temperature -20°C-4 °F

Electrical

Conductivity and insulation.

Electrical Conductivity

9.4 % IACS
8.8 % IACS

Electrical Resistivity

1.83×10⁻⁷ Ω·m7.2 µΩ·in
1.95×10⁻⁷ Ω·m7.68 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Same in both: Galvanic Potential (seawater, vs SCE) -0.61 V · Corrosion Resistance 10 / 100

Manufacturability

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

Machinability

38 / 100
20 / 100

Machinability Rating (AISI 1212 = 100 %)

32%
16%

Weldability

12 / 100
6 / 100

Formability (cold)

22 / 100
8 / 100

Same in both: Castability 25 / 100 · Brazeability / Solderability 50 / 100 · Polishability 70 / 100

Sustainability

Primary-production footprint per kilogram.

Same in both: Embodied Energy (primary production) 32 MJ/kg13,758 BTU/lb · Embodied Carbon (primary production) 2.3 kg CO₂/kg · Embodied Water 60 L/kg7.2 gal/lb · Typical Recycled Content 30%

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 scaleSK95

SK95-N vs SK95-QT400 — frequently asked

Is SK95-QT400 stronger than SK95-N?

Yes. SK95-QT400 has a typical yield strength of 1,300 MPa (189 ksi) against 520 MPa (75.4 ksi) for SK95-N — about 150% more. Tensile strength is 1,500 MPa (218 ksi) vs 900 MPa (131 ksi).

Which condition does FabDigit quote by default, N or QT400?

A is the default SK95 condition in the FabDigit quote flow (neither N nor QT400). The other condition is available on request or by drawing note — specify it in the material field or the part notes and the quote is priced for it.

Which is easier to machine, SK95-N or SK95-QT400?

SK95-N. Its machinability rates fair (38/100) against poor (20/100) for SK95-QT400; for welding the order is SK95-N first (not recommended, 12/100) then SK95-QT400 (not recommended, 6/100).

Ready to make it?

Upload a CAD file and FabDigit prices the part in SK95-N and SK95-QT400 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.