Steel C12 A+T vs C12 Q+T
Steel · C12 temper comparison
C12 A+T and C12 Q+T are two conditions of the same steel grade, C12: A+T (full annealed and tempered) versus Q+T (quenched and tempered). The chemistry is identical, so every difference below comes from the condition. C12 Q+T is the stronger of the two: yield strength 520 MPa (75.4 ksi) against 440 MPa (63.8 ksi) for C12 A+T, about 18% more; tensile strength follows at 710 MPa (103 ksi) vs 630 MPa (91.4 ksi). In exchange, C12 A+T is the more ductile: elongation 24% versus 20% for C12 Q+T, and C12 Q+T is harder (220 HB vs 185 HB). On the shop floor, C12 A+T machines more easily (45 vs 35 out of 100).
C12 A+TChoose it when the part is bent, formed or impact-loaded, or when the part is machined in volume.
C12 Q+TChoose it when strength drives the design.
C12 A+T vs C12 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.
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)
Hardness, Brinell
Hardness, Rockwell B
Hardness, Rockwell C
Hardness, Vickers
Same in both: Elastic (Young's) Modulus 207 GPa30 Msi · Shear Modulus 80 GPa11.6 Msi · Bulk Modulus 160 GPa23.2 Msi · Poisson's Ratio 0.3 · Charpy V-Notch Impact (RT) 45 J33.2 ft·lbf
Physical
Density and transition temperatures.
Same in both: Density 7.79 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.
Same in both: Thermal Conductivity 26 W/m·K15 BTU/hr·ft·°F · Specific Heat Capacity 460 J/kg·K0.11 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 11.2 µm/m·K6.2 µin/in·°F · Latent Heat of Fusion 270 J/g116 BTU/lb · Max Service Temperature (continuous) 600°C1,112 °F · Min Service Temperature -29°C-20 °F
Electrical
Conductivity and insulation.
Same in both: Electrical Conductivity 2.9 % IACS · Electrical Resistivity 6×10⁻⁷ Ω·m23.6 µΩ·in
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Same in both: Galvanic Potential (seawater, vs SCE) -0.55 V · Corrosion Resistance 32 / 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 60 / 100 · Brazeability / Solderability 40 / 100 · Polishability 60 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 32 MJ/kg13,758 BTU/lb · Embodied Carbon (primary production) 2.5 kg CO₂/kg · Embodied Water 60 L/kg7.2 gal/lb · Typical Recycled Content 75%
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.
C12 A+T vs C12 Q+T — frequently asked
Is C12 Q+T stronger than C12 A+T?
Yes. C12 Q+T has a typical yield strength of 520 MPa (75.4 ksi) against 440 MPa (63.8 ksi) for C12 A+T — about 18% more. Tensile strength is 710 MPa (103 ksi) vs 630 MPa (91.4 ksi).
Which condition does FabDigit quote by default, A+T or Q+T?
N+T is the default C12 condition in the FabDigit quote flow (neither A+T nor Q+T). 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, C12 A+T or C12 Q+T?
C12 A+T, by a small margin. Both rate fair for machinability — 45/100 against 35/100 for C12 Q+T.
Ready to make it?
Upload a CAD file and FabDigit prices the part in C12 A+T and C12 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.