Steel 12Cr2Ni4A-A vs 12Cr2Ni4A-QT
Steel · 12Cr2Ni4A temper comparison
12Cr2Ni4A-A and 12Cr2Ni4A-QT are two conditions of the same steel grade, 12Cr2Ni4A: A (solution annealed) versus QT (quenched and tempered). The chemistry is identical, so every difference below comes from the condition. 12Cr2Ni4A-QT is the stronger of the two: yield strength 950 MPa (138 ksi) against 450 MPa (65.3 ksi) for 12Cr2Ni4A-A, about 111% more; tensile strength follows at 1,180 MPa (171 ksi) vs 700 MPa (102 ksi). In exchange, 12Cr2Ni4A-A is the more ductile: elongation 20% versus 12% for 12Cr2Ni4A-QT, and 12Cr2Ni4A-QT is harder (370 HB vs 240 HB). 12Cr2Ni4A-A runs hotter in service (500°C vs 200°C continuous). On the shop floor, 12Cr2Ni4A-A machines more easily (fair vs poor) and 12Cr2Ni4A-A welds better (fair vs poor).
12Cr2Ni4A-AChoose it when the part is bent, formed or impact-loaded, or when the part sees heat.
12Cr2Ni4A-QTChoose it when strength drives the design.
12Cr2Ni4A-A vs 12Cr2Ni4A-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
Fatigue Strength (Endurance Limit)
Charpy V-Notch Impact (RT)
Hardness, Brinell
Same in both: Elastic (Young's) Modulus 210 GPa30.5 Msi · Shear Modulus 80 GPa11.6 Msi · Bulk Modulus 160 GPa23.2 Msi · Poisson's Ratio 0.29 · Compressive Strength 980 MPa142 ksi · Shear Strength 710 MPa103 ksi · Fracture Toughness (K_IC) 100 MPa·√m91 ksi·√in · Hardness, Rockwell C 39 HRC · Hardness, Vickers 390 HV
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 1,490°C2,714 °F
Thermal
How each material carries heat and how hot it can run.
Max Service Temperature (continuous)
Same in both: Thermal Conductivity 33 W/m·K19.1 BTU/hr·ft·°F · Specific Heat Capacity 470 J/kg·K0.11 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 11.5 µm/m·K6.4 µin/in·°F · Latent Heat of Fusion 250 J/g107 BTU/lb · Min Service Temperature -70°C-94 °F
Electrical
Conductivity and insulation.
Same in both: Electrical Conductivity 5.7 % IACS · Electrical Resistivity 3×10⁻⁷ Ω·m11.8 µΩ·in
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 55 / 100 · Polishability 75 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 36 MJ/kg15,477 BTU/lb · Embodied Carbon (primary production) 2.6 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.
12Cr2Ni4A-A vs 12Cr2Ni4A-QT — frequently asked
Is 12Cr2Ni4A-QT stronger than 12Cr2Ni4A-A?
Yes. 12Cr2Ni4A-QT has a typical yield strength of 950 MPa (138 ksi) against 450 MPa (65.3 ksi) for 12Cr2Ni4A-A — about 111% more. Tensile strength is 1,180 MPa (171 ksi) vs 700 MPa (102 ksi).
Which condition does FabDigit quote by default, A or QT?
QT is the default 12Cr2Ni4A 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, 12Cr2Ni4A-A or 12Cr2Ni4A-QT?
12Cr2Ni4A-A. Its machinability rates fair (45/100) against poor (32/100) for 12Cr2Ni4A-QT; for welding the order is 12Cr2Ni4A-A first (fair, 40/100) then 12Cr2Ni4A-QT (poor, 30/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in 12Cr2Ni4A-A and 12Cr2Ni4A-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.