Steel 20MnNb6 +N vs 20MnNb6 +QT
Steel · 20MnNb6 temper comparison
20MnNb6 +N and 20MnNb6 +QT are two conditions of the same steel grade, 20MnNb6: +N (normalized) versus +QT (quenched and tempered). The chemistry is identical, so every difference below comes from the condition. 20MnNb6 +QT is the stronger of the two: yield strength 460 MPa (66.7 ksi) against 385 MPa (55.8 ksi) for 20MnNb6 +N, about 19% more; tensile strength follows at 590 MPa (85.6 ksi) vs 540 MPa (78.3 ksi). In exchange, 20MnNb6 +N is the more ductile: elongation 25% versus 22% for 20MnNb6 +QT, and 20MnNb6 +QT is harder (180 HB vs 155 HB).
20MnNb6 +NChoose it when the part is bent, formed or impact-loaded.
20MnNb6 +QTChoose it when strength drives the design.
20MnNb6 +N vs 20MnNb6 +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.
Mechanical
Strength, stiffness, ductility and hardness at room temperature.
Tensile Strength (Ultimate)
Yield Strength (0.2% offset)
Elongation at Break
Reduction in Area
Fatigue Strength (Endurance Limit)
Fracture Toughness (K_IC)
Charpy V-Notch Impact (RT)
Hardness, Brinell
Hardness, Rockwell B
Same in both: Elastic (Young's) Modulus 210 GPa30.5 Msi · Shear Modulus 81 GPa11.7 Msi · Bulk Modulus 160 GPa23.2 Msi · Poisson's Ratio 0.29 · Compressive Strength 385 MPa55.8 ksi · Shear Strength 330 MPa47.9 ksi · Hardness, Vickers 163 HV
Physical
Density and transition temperatures.
Same in both: Density 7.85 g/cm³0.28 lb/in³ · Melting Point (Solidus) 1,490°C2,714 °F · Liquidus Temperature 1,520°C2,768 °F
Thermal
How each material carries heat and how hot it can run.
Same in both: Thermal Conductivity 48 W/m·K27.7 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 250 J/g107 BTU/lb · Max Service Temperature (continuous) 400°C752 °F · Min Service Temperature -20°C-4 °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) -0.62 V · Corrosion Resistance 11 / 100
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability Rating (AISI 1212 = 100 %)
Formability (cold)
Same in both: Machinability 60 / 100 · Weldability 88 / 100 · Castability 40 / 100 · Brazeability / Solderability 60 / 100 · Polishability 45 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 25 MJ/kg10,748 BTU/lb · Embodied Carbon (primary production) 2.1 kg CO₂/kg · Embodied Water 50 L/kg6 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.
20MnNb6 +N vs 20MnNb6 +QT — frequently asked
Is 20MnNb6 +QT stronger than 20MnNb6 +N?
Yes. 20MnNb6 +QT has a typical yield strength of 460 MPa (66.7 ksi) against 385 MPa (55.8 ksi) for 20MnNb6 +N — about 19% more. Tensile strength is 590 MPa (85.6 ksi) vs 540 MPa (78.3 ksi).
Which condition does FabDigit quote by default, +N or +QT?
+N is the default 20MnNb6 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.
When should I choose 20MnNb6 +N over 20MnNb6 +QT?
Pick 20MnNb6 +N when the part is bent, formed or impact-loaded. Pick 20MnNb6 +QT when strength drives the design.
Ready to make it?
Upload a CAD file and FabDigit prices the part in 20MnNb6 +N and 20MnNb6 +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.