Steel 15NiCuMoNb5-6-4-NT vs 15NiCuMoNb5-6-4-QT
Steel · 15NiCuMoNb5-6-4 temper comparison
15NiCuMoNb5-6-4-NT and 15NiCuMoNb5-6-4-QT are two conditions of the same steel grade, 15NiCuMoNb5-6-4: NT versus QT (quenched and tempered). The chemistry is identical, so every difference below comes from the condition. 15NiCuMoNb5-6-4-QT is the stronger of the two: yield strength 530 MPa (76.9 ksi) against 480 MPa (69.6 ksi) for 15NiCuMoNb5-6-4-NT, about 10% more; tensile strength follows at 700 MPa (102 ksi) vs 660 MPa (95.7 ksi). 15NiCuMoNb5-6-4-QT is harder — 220 HB against 205 HB for 15NiCuMoNb5-6-4-NT — which matters for wear surfaces and threads.
15NiCuMoNb5-6-4-QTChoose it when strength drives the design, or when surface hardness matters.
15NiCuMoNb5-6-4-NT vs 15NiCuMoNb5-6-4-QT: propertiesHow to read these bars
- One bar per material. A full bar is the highest value among all steel grades in the FabDigit library; each bar is drawn as a share of that.
- The better value (by the usual engineering direction) is in bold. Rows with no direction — density, thermal conductivity — have no bold.
- Values are typical room-temperature figures for the condition named on each card.
- Confirm against the certified mill or resin datasheet before design release.
How to read these bars
- One bar per material. A full bar is the highest value among all steel grades in the FabDigit library; each bar is drawn as a share of that.
- The better value (by the usual engineering direction) is in bold. Rows with no direction — density, thermal conductivity — have no bold.
- Values are typical room-temperature figures for the condition named on each card.
- Confirm against the certified mill or resin datasheet before design release.
15NiCuMoNb5-6-4-NT15NiCuMoNb5-6-4-QT
Mechanical
Strength, stiffness, ductility and hardness at room temperature.
Tensile Strength (Ultimate)
Yield Strength (0.2% offset)
Elongation at Break
Reduction in Area
Compressive Strength
Shear Strength
Fatigue Strength (Endurance Limit)
Fracture Toughness (K_IC)
Charpy V-Notch Impact (RT)
Hardness, Brinell
Hardness, Rockwell B
Hardness, Rockwell C
Hardness, Vickers
Same in both: Elastic (Young's) Modulus 211 GPa30.6 Msi · Shear Modulus 81 GPa11.7 Msi · Bulk Modulus 165 GPa23.9 Msi · Poisson's Ratio 0.29
Physical
Density and transition temperatures.
Same in both: Density 7.85 g/cm³0.28 lb/in³ · Melting Point (Solidus) 1,460°C2,660 °F · Liquidus Temperature 1,510°C2,750 °F
Thermal
How each material carries heat and how hot it can run.
Same in both: Thermal Conductivity 40 W/m·K23.1 BTU/hr·ft·°F · Specific Heat Capacity 470 J/kg·K0.11 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 12 µm/m·K6.7 µin/in·°F · Latent Heat of Fusion 270 J/g116 BTU/lb · Max Service Temperature (continuous) 400°C752 °F · Min Service Temperature -20°C-4 °F
Electrical
Conductivity and insulation.
Same in both: Electrical Resistivity 2.2×10⁻⁷ Ω·m8.66 µΩ·in
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Same in both: Galvanic Potential (seawater, vs SCE) -0.6 V · Corrosion Resistance 18 / 100
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Machinability Rating (AISI 1212 = 100 %)
Weldability
Formability (cold)
Same in both: Polishability 55 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 27 MJ/kg11,608 BTU/lb · Embodied Carbon (primary production) 2.1 kg CO₂/kg · Embodied Water 45 L/kg5.4 gal/lb · Typical Recycled Content 25%
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.
15NiCuMoNb5-6-4-NT vs 15NiCuMoNb5-6-4-QT — frequently asked
Is 15NiCuMoNb5-6-4-QT stronger than 15NiCuMoNb5-6-4-NT?
Yes. 15NiCuMoNb5-6-4-QT has a typical yield strength of 530 MPa (76.9 ksi) against 480 MPa (69.6 ksi) for 15NiCuMoNb5-6-4-NT — about 10% more. Tensile strength is 700 MPa (102 ksi) vs 660 MPa (95.7 ksi).
Which condition does FabDigit quote by default, NT or QT?
NT is the default 15NiCuMoNb5-6-4 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, 15NiCuMoNb5-6-4-NT or 15NiCuMoNb5-6-4-QT?
15NiCuMoNb5-6-4-NT. Its machinability rates good (55/100) against fair (50/100) for 15NiCuMoNb5-6-4-QT.
Ready to make it?
Upload a CAD file and FabDigit prices the part in 15NiCuMoNb5-6-4-NT and 15NiCuMoNb5-6-4-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.