Steel T12A-HR vs T12A-QT350
Steel · T12A temper comparison
T12A-HR and T12A-QT350 are two conditions of the same steel grade, T12A: HR (hot rolled) versus QT350 (water quenched + tempered 300–400 °C). The chemistry is identical, so every difference below comes from the condition. T12A-QT350 is the stronger of the two: yield strength 1,450 MPa (210 ksi) against 480 MPa (69.6 ksi) for T12A-HR, about 3.0 times as much; tensile strength follows at 1,700 MPa (247 ksi) vs 850 MPa (123 ksi). In exchange, T12A-HR is the more ductile: elongation 10% versus 4% for T12A-QT350, and T12A-QT350 is harder (512 HB vs 255 HB). T12A-HR runs hotter in service (400°C vs 300°C continuous). On the shop floor, T12A-HR machines more easily (poor vs not recommended).
T12A-HRChoose it when the part is bent, formed or impact-loaded, or when the part sees heat.
T12A-QT350Choose it when strength drives the design.
T12A-HR vs T12A-QT350: 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, Vickers
Same in both: Elastic (Young's) Modulus 210 GPa30.5 Msi · Shear Modulus 81 GPa11.7 Msi · Bulk Modulus 165 GPa23.9 Msi · Poisson's Ratio 0.29 · Hardness, Rockwell B 93 HRB
Physical
Density and transition temperatures.
Same in both: Density 7.85 g/cm³0.28 lb/in³ · Melting Point (Solidus) 1,300°C2,372 °F · Liquidus Temperature 1,440°C2,624 °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 470 J/kg·K0.11 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 11.8 µm/m·K6.6 µin/in·°F · Latent Heat of Fusion 250 J/g107 BTU/lb · Min Service Temperature -20°C-4 °F
Electrical
Conductivity and insulation.
Electrical Conductivity
Electrical Resistivity
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Same in both: Galvanic Potential (seawater, vs SCE) -0.62 V · Corrosion Resistance 9 / 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 70 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 28 MJ/kg12,038 BTU/lb · Embodied Carbon (primary production) 2.1 kg CO₂/kg · Embodied Water 60 L/kg7.2 gal/lb · Typical Recycled Content 30%
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.
T12A-HR vs T12A-QT350 — frequently asked
Is T12A-QT350 stronger than T12A-HR?
Yes. T12A-QT350 has a typical yield strength of 1,450 MPa (210 ksi) against 480 MPa (69.6 ksi) for T12A-HR — about 3.0 times as much. Tensile strength is 1,700 MPa (247 ksi) vs 850 MPa (123 ksi).
Which condition does FabDigit quote by default, HR or QT350?
A is the default T12A condition in the FabDigit quote flow (neither HR nor QT350). 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, T12A-HR or T12A-QT350?
T12A-HR. Its machinability rates poor (30/100) against not recommended (12/100) for T12A-QT350; for welding the order is T12A-HR first (not recommended, 12/100) then T12A-QT350 (not recommended, 4/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in T12A-HR and T12A-QT350 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.