Steel A757 Grade C3 N&T vs A757 Grade C3 Q&T
Steel · A757 Grade C3 temper comparison
A757 Grade C3 N&T and A757 Grade C3 Q&T are two conditions of the same steel grade, A757 Grade C3: N&T (normalized and tempered) versus Q&T (quenched and tempered). The chemistry is identical, so every difference below comes from the condition. A757 Grade C3 Q&T is the stronger of the two: yield strength 460 MPa (66.7 ksi) against 400 MPa (58 ksi) for A757 Grade C3 N&T, about 15% more; tensile strength follows at 620 MPa (89.9 ksi) vs 570 MPa (82.7 ksi). A757 Grade C3 Q&T is harder — 190 HB against 175 HB for A757 Grade C3 N&T — which matters for wear surfaces and threads.
A757 Grade C3 Q&TChoose it when strength drives the design, or when surface hardness matters.
A757 Grade C3 N&T vs A757 Grade C3 Q&T: 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.
A757 Grade C3 N&TA757 Grade C3 Q&T
Mechanical
Strength, stiffness, ductility and hardness at room temperature.
Tensile Strength (Ultimate)
Yield Strength (0.2% offset)
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
Same in both: Elastic (Young's) Modulus 202 GPa29.3 Msi · Shear Modulus 78 GPa11.3 Msi · Bulk Modulus 160 GPa23.2 Msi · Poisson's Ratio 0.29 · Elongation at Break 24%
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 1,500°C2,732 °F
Thermal
How each material carries heat and how hot it can run.
Thermal Conductivity
Same in both: Specific Heat Capacity 480 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 -100°C-148 °F
Electrical
Conductivity and insulation.
Same in both: Electrical Resistivity 2.6×10⁻⁷ Ω·m10.2 µΩ·in
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Same in both: Galvanic Potential (seawater, vs SCE) -0.61 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: Castability 68 / 100 · Brazeability / Solderability 55 / 100 · Polishability 60 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 30 MJ/kg12,898 BTU/lb · Embodied Carbon (primary production) 2.3 kg CO₂/kg · Embodied Water 55 L/kg6.6 gal/lb · Typical Recycled Content 85%
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.
A757 Grade C3 N&T vs A757 Grade C3 Q&T — frequently asked
Is A757 Grade C3 Q&T stronger than A757 Grade C3 N&T?
Yes. A757 Grade C3 Q&T has a typical yield strength of 460 MPa (66.7 ksi) against 400 MPa (58 ksi) for A757 Grade C3 N&T — about 15% more. Tensile strength is 620 MPa (89.9 ksi) vs 570 MPa (82.7 ksi).
Which condition does FabDigit quote by default, N&T or Q&T?
Q&T is the default A757 Grade C3 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, A757 Grade C3 N&T or A757 Grade C3 Q&T?
A757 Grade C3 N&T, by a small margin. Both rate good for machinability — 60/100 against 55/100 for A757 Grade C3 Q&T.
Ready to make it?
Upload a CAD file and FabDigit prices the part in A757 Grade C3 N&T and A757 Grade C3 Q&T 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.