Steel X7Ni9 +NT vs X7Ni9 +QT
Steel · X7Ni9 temper comparison
X7Ni9 +NT and X7Ni9 +QT are two conditions of the same steel grade, X7Ni9: +NT (normalized and tempered) versus +QT (quenched and tempered). The chemistry is identical, so every difference below comes from the condition. X7Ni9 +QT is the stronger of the two: yield strength 640 MPa (92.8 ksi) against 550 MPa (79.8 ksi) for X7Ni9 +NT, about 16% more. X7Ni9 +QT is harder — 215 HB against 200 HB for X7Ni9 +NT — which matters for wear surfaces and threads.
X7Ni9 +QTChoose it when strength drives the design, or when surface hardness matters.
X7Ni9 +NT vs X7Ni9 +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
Fatigue Strength (Endurance Limit)
Fracture Toughness (K_IC)
Charpy V-Notch Impact (RT)
Hardness, Brinell
Hardness, Vickers
Same in both: Elastic (Young's) Modulus 195 GPa28.3 Msi · Shear Modulus 76 GPa11 Msi · Bulk Modulus 160 GPa23.2 Msi · Poisson's Ratio 0.29 · Reduction in Area 65% · Compressive Strength 640 MPa92.8 ksi · Shear Strength 440 MPa63.8 ksi · Hardness, Rockwell B 96 HRB · Hardness, Rockwell C 19 HRC
Physical
Density and transition temperatures.
Same in both: Density 7.85 g/cm³0.28 lb/in³ · Melting Point (Solidus) 1,430°C2,606 °F · Liquidus Temperature 1,500°C2,732 °F
Thermal
How each material carries heat and how hot it can run.
Same in both: Thermal Conductivity 30 W/m·K17.3 BTU/hr·ft·°F · Specific Heat Capacity 460 J/kg·K0.11 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 10.2 µm/m·K5.7 µin/in·°F · Latent Heat of Fusion 270 J/g116 BTU/lb · Max Service Temperature (continuous) 350°C662 °F · Min Service Temperature -196°C-321 °F
Electrical
Conductivity and insulation.
Same in both: Electrical Conductivity 3.8 % IACS · Electrical Resistivity 4.5×10⁻⁷ Ω·m17.7 µΩ·in
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Same in both: Galvanic Potential (seawater, vs SCE) -0.6 V · Corrosion Resistance 16 / 100
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Formability (cold)
Same in both: Machinability Rating (AISI 1212 = 100 %) 40% · Weldability 55 / 100 · Brazeability / Solderability 40 / 100 · Polishability 60 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 40 MJ/kg17,197 BTU/lb · Embodied Carbon (primary production) 3 kg CO₂/kg · Embodied Water 60 L/kg7.2 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.
X7Ni9 +NT vs X7Ni9 +QT — frequently asked
Is X7Ni9 +QT stronger than X7Ni9 +NT?
Yes. X7Ni9 +QT has a typical yield strength of 640 MPa (92.8 ksi) against 550 MPa (79.8 ksi) for X7Ni9 +NT — about 16% more. Tensile strength is 730 MPa (106 ksi) vs 700 MPa (102 ksi).
Which condition does FabDigit quote by default, +NT or +QT?
+QT is the default X7Ni9 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 X7Ni9 +NT over X7Ni9 +QT?
Pick X7Ni9 +QT when strength drives the design, or when surface hardness matters.
Ready to make it?
Upload a CAD file and FabDigit prices the part in X7Ni9 +NT and X7Ni9 +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.