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Steel SC450-N vs SC450-QT

Steel · SC450 temper comparison

SC450-N and SC450-QT are two conditions of the same steel grade, SC450: N (normalized) versus QT (quenched and tempered). The chemistry is identical, so every difference below comes from the condition. SC450-QT is the stronger of the two: yield strength 410 MPa (59.5 ksi) against 275 MPa (39.9 ksi) for SC450-N, about 49% more; tensile strength follows at 590 MPa (85.6 ksi) vs 495 MPa (71.8 ksi). In exchange, SC450-N is the more ductile: elongation 24% versus 21% for SC450-QT, and SC450-QT is harder (185 HB vs 145 HB).

SC450-NChoose it when the part is bent, formed or impact-loaded.

SC450-QTChoose it when strength drives the design.

SC450-N vs SC450-QT: properties

SC450-NSC450-QT

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Tensile Strength (Ultimate)

495 MPa71.8 ksi
590 MPa85.6 ksi

Yield Strength (0.2% offset)

275 MPa39.9 ksi
410 MPa59.5 ksi

Elongation at Break

24%
21%

Reduction in Area

40%
45%

Fatigue Strength (Endurance Limit)

215 MPa31.2 ksi
260 MPa37.7 ksi

Fracture Toughness (K_IC)

80 MPa·√m72.8 ksi·√in
95 MPa·√m86.5 ksi·√in

Charpy V-Notch Impact (RT)

30 J22.1 ft·lbf
45 J33.2 ft·lbf

Hardness, Brinell

145 HB
185 HB

Hardness, Rockwell B

78 HRB
90 HRB

Same in both: Elastic (Young's) Modulus 205 GPa29.7 Msi · Shear Modulus 79 GPa11.5 Msi · Bulk Modulus 160 GPa23.2 Msi · Poisson's Ratio 0.29 · Compressive Strength 275 MPa39.9 ksi · Shear Strength 350 MPa50.8 ksi · Hardness, Vickers 152 HV

Physical

Density and transition temperatures.

Same in both: Density 7.85 g/cm³0.28 lb/in³ · Melting Point (Solidus) 1,425°C2,597 °F · Liquidus Temperature 1,505°C2,741 °F

Thermal

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

Min Service Temperature

-20°C-4 °F
-40°C-40 °F

Same in both: Thermal Conductivity 50 W/m·K28.9 BTU/hr·ft·°F · Specific Heat Capacity 470 J/kg·K0.11 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 11.9 µm/m·K6.6 µin/in·°F · Latent Heat of Fusion 250 J/g107 BTU/lb · Max Service Temperature (continuous) 425°C797 °F

Electrical

Conductivity and insulation.

Same in both: Electrical Conductivity 10 % IACS · Electrical Resistivity 1.7×10⁻⁷ Ω·m6.69 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Same in both: Galvanic Potential (seawater, vs SCE) -0.65 V · Corrosion Resistance 12 / 100

Manufacturability

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

Machinability

62 / 100
53 / 100

Machinability Rating (AISI 1212 = 100 %)

65%
55%

Weldability

78 / 100
72 / 100

Same in both: Formability (cold) 20 / 100 · Castability 70 / 100 · Brazeability / Solderability 65 / 100 · Polishability 55 / 100

Sustainability

Primary-production footprint per kilogram.

Same in both: Embodied Energy (primary production) 26 MJ/kg11,178 BTU/lb · Embodied Carbon (primary production) 2.1 kg CO₂/kg · Embodied Water 50 L/kg6 gal/lb · Typical Recycled Content 80%

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 scaleSC450

SC450-N vs SC450-QT — frequently asked

Is SC450-QT stronger than SC450-N?

Yes. SC450-QT has a typical yield strength of 410 MPa (59.5 ksi) against 275 MPa (39.9 ksi) for SC450-N — about 49% more. Tensile strength is 590 MPa (85.6 ksi) vs 495 MPa (71.8 ksi).

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

N is the default SC450 condition in the FabDigit quote flow. 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, SC450-N or SC450-QT?

SC450-N. Its machinability rates good (62/100) against fair (53/100) for SC450-QT; for welding the order is SC450-N first (very good, 78/100) then SC450-QT (very good, 72/100).

Ready to make it?

Upload a CAD file and FabDigit prices the part in SC450-N and SC450-QT 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.