Steel A372 Grade K-N vs A372 Grade K-QT
Steel · A372 Grade K temper comparison
A372 Grade K-N and A372 Grade K-QT are two conditions of the same steel grade, A372 Grade K: N (normalized) versus QT (quenched and tempered). The chemistry is identical, so every difference below comes from the condition. A372 Grade K-QT is the stronger of the two: yield strength 725 MPa (105 ksi) against 470 MPa (68.2 ksi) for A372 Grade K-N, about 54% more; tensile strength follows at 860 MPa (125 ksi) vs 760 MPa (110 ksi). A372 Grade K-QT is harder — 255 HB against 230 HB for A372 Grade K-N — which matters for wear surfaces and threads.
A372 Grade K-QTChoose it when strength drives the design, or when surface hardness matters.
A372 Grade K-N vs A372 Grade K-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
Compressive Strength
Shear Strength
Fatigue Strength (Endurance Limit)
Fracture Toughness (K_IC)
Charpy V-Notch Impact (RT)
Hardness, Brinell
Hardness, Rockwell C
Hardness, Vickers
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
Physical
Density and transition temperatures.
Same in both: Density 7.85 g/cm³0.28 lb/in³ · Melting Point (Solidus) 1,420°C2,588 °F · Liquidus Temperature 1,490°C2,714 °F
Thermal
How each material carries heat and how hot it can run.
Thermal Conductivity
Same in both: Specific Heat Capacity 470 J/kg·K0.11 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 12.3 µm/m·K6.8 µin/in·°F · Latent Heat of Fusion 250 J/g107 BTU/lb · Max Service Temperature (continuous) 400°C752 °F · Min Service Temperature -29°C-20 °F
Electrical
Conductivity and insulation.
Electrical Resistivity
Same in both: Electrical Conductivity 8 % IACS
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Same in both: Galvanic Potential (seawater, vs SCE) -0.6 V · Corrosion Resistance 13 / 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: Brazeability / Solderability 50 / 100 · Polishability 62 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 26 MJ/kg11,178 BTU/lb · Embodied Carbon (primary production) 1.9 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.
A372 Grade K-N vs A372 Grade K-QT — frequently asked
Is A372 Grade K-QT stronger than A372 Grade K-N?
Yes. A372 Grade K-QT has a typical yield strength of 725 MPa (105 ksi) against 470 MPa (68.2 ksi) for A372 Grade K-N — about 54% more. Tensile strength is 860 MPa (125 ksi) vs 760 MPa (110 ksi).
Which condition does FabDigit quote by default, N or QT?
QT is the default A372 Grade K 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 A372 Grade K-N over A372 Grade K-QT?
Pick A372 Grade K-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 A372 Grade K-N and A372 Grade K-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.