Steel T15-ANN vs T15 QT-65-67
Steel · T15 temper comparison
T15-ANN and T15 QT-65-67 are two conditions of the same steel grade, T15: ANN (annealed) versus QT-65-67 (hardened & triple tempered to 65–67 HRC). The chemistry is identical, so every difference below comes from the condition. T15 QT-65-67 is the stronger of the two: tensile strength 2,200 MPa (319 ksi) against 830 MPa (120 ksi) for T15-ANN, about 165% more. In exchange, T15-ANN is the more ductile: elongation 12% versus 0.3% for T15 QT-65-67, and T15 QT-65-67 is harder (66 HRC vs 24 HRC). T15 QT-65-67 runs hotter in service (620°C vs 400°C continuous). On the shop floor, T15-ANN machines more easily (poor vs not recommended).
T15-ANNChoose it when the part is bent, formed or impact-loaded, or when the part is machined in volume.
T15 QT-65-67Choose it when strength drives the design, or when the part sees heat.
T15-ANN vs T15 QT-65-67: 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)
Elongation at Break
Compressive Strength
Charpy V-Notch Impact (RT)
Hardness, Rockwell C
Hardness, Vickers
Same in both: Shear Modulus 84 GPa12.2 Msi · Bulk Modulus 165 GPa23.9 Msi · Poisson's Ratio 0.29 · Yield Strength (0.2% offset) 500 MPa72.5 ksi · Reduction in Area 22% · Hardness, Brinell 255 HB
Physical
Density and transition temperatures.
Same in both: Density 8.19 g/cm³0.3 lb/in³ · Melting Point (Solidus) 1,230°C2,246 °F · Liquidus Temperature 1,420°C2,588 °F
Thermal
How each material carries heat and how hot it can run.
Max Service Temperature (continuous)
Same in both: Thermal Conductivity 21 W/m·K12.1 BTU/hr·ft·°F · Specific Heat Capacity 420 J/kg·K0.1 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 11.2 µm/m·K6.2 µin/in·°F · Latent Heat of Fusion 250 J/g107 BTU/lb · Min Service Temperature -60°C-76 °F
Electrical
Conductivity and insulation.
Same in both: Electrical Conductivity 2.7 % IACS · Electrical Resistivity 6.5×10⁻⁷ Ω·m25.6 µΩ·in
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Same in both: Galvanic Potential (seawater, vs SCE) -0.55 V · Corrosion Resistance 15 / 100
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Machinability Rating (AISI 1212 = 100 %)
Formability (cold)
Same in both: Weldability 20 / 100 · Brazeability / Solderability 45 / 100 · Polishability 70 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 52 MJ/kg22,356 BTU/lb · Embodied Carbon (primary production) 3.8 kg CO₂/kg · Embodied Water 80 L/kg9.6 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.
T15-ANN vs T15 QT-65-67 — frequently asked
Is T15 QT-65-67 stronger than T15-ANN?
Yes. T15 QT-65-67 has a typical tensile strength of 2,200 MPa (319 ksi) against 830 MPa (120 ksi) for T15-ANN — about 165% more.
Which condition does FabDigit quote by default, ANN or QT-65-67?
ANN is the default T15 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, T15-ANN or T15 QT-65-67?
T15-ANN. Its machinability rates poor (22/100) against not recommended (4/100) for T15 QT-65-67.
Ready to make it?
Upload a CAD file and FabDigit prices the part in T15-ANN and T15 QT-65-67 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.