Steel C12A-AC vs C12A Q+T
Steel · C12A temper comparison
C12A-AC and C12A Q+T are two conditions of the same steel grade, C12A: AC (spheroidize annealed) versus Q+T (quenched and tempered). The chemistry is identical, so every difference below comes from the condition. C12A-AC is the stronger of the two: yield strength 800 MPa (116 ksi) against 520 MPa (75.4 ksi) for C12A Q+T, about 54% more; tensile strength follows at 1,150 MPa (167 ksi) vs 700 MPa (102 ksi). In exchange, C12A Q+T is the more ductile: elongation 19% versus 5% for C12A-AC, and C12A-AC is harder (400 HB vs 232 HB). C12A Q+T runs hotter in service (600°C vs 200°C continuous) and C12A Q+T conducts electricity better (2.9 % IACS vs 2.6 % IACS). On the shop floor, C12A Q+T machines more easily (fair vs poor) and C12A Q+T welds better (fair vs not recommended).
C12A-ACChoose it when strength drives the design.
C12A Q+TChoose it when the part is bent, formed or impact-loaded, or when the part sees heat.
C12A-AC vs C12A 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.
Elastic (Young's) Modulus
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: Shear Modulus 84 GPa12.2 Msi · Bulk Modulus 160 GPa23.2 Msi · Poisson's Ratio 0.3
Physical
Density and transition temperatures.
Same in both: Density 7.77 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
Max Service Temperature (continuous)
Same in both: Specific Heat Capacity 460 J/kg·K0.11 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 10.8 µm/m·K6 µin/in·°F · Latent Heat of Fusion 270 J/g116 BTU/lb · Min Service Temperature -30°C-22 °F
Electrical
Conductivity and insulation.
Electrical Conductivity
Electrical Resistivity
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Corrosion Resistance
Same in both: Galvanic Potential (seawater, vs SCE) -0.52 V
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 55 / 100 · Brazeability / Solderability 25 / 100 · Polishability 60 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 33 MJ/kg14,187 BTU/lb · Embodied Carbon (primary production) 2.4 kg CO₂/kg · Embodied Water 45 L/kg5.4 gal/lb · Typical Recycled Content 80%
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.
C12A-AC vs C12A Q+T — frequently asked
Is C12A-AC stronger than C12A Q+T?
Yes. C12A-AC has a typical yield strength of 800 MPa (116 ksi) against 520 MPa (75.4 ksi) for C12A Q+T — about 54% more. Tensile strength is 1,150 MPa (167 ksi) vs 700 MPa (102 ksi).
Which condition does FabDigit quote by default, AC or Q+T?
N+T is the default C12A condition in the FabDigit quote flow (neither AC 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, C12A-AC or C12A Q+T?
C12A Q+T. Its machinability rates fair (36/100) against poor (15/100) for C12A-AC; for welding the order is C12A Q+T first (fair, 38/100) then C12A-AC (not recommended, 12/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in C12A-AC and C12A 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.