Steel T8A-HR vs T8A-QT300
Steel · T8A temper comparison
T8A-HR and T8A-QT300 are two conditions of the same steel grade, T8A: HR (hot rolled) versus QT300 (quenched and tempered ~300 °C). The chemistry is identical, so every difference below comes from the condition. T8A-QT300 is the stronger of the two: yield strength 1,650 MPa (239 ksi) against 450 MPa (65.3 ksi) for T8A-HR, about 3.7 times as much; tensile strength follows at 1,950 MPa (283 ksi) vs 830 MPa (120 ksi). In exchange, T8A-HR is the more ductile: elongation 12% versus 3% for T8A-QT300, and T8A-HR is harder (240 HB vs 179 HB). On the shop floor, T8A-HR machines more easily (fair vs not recommended).
T8A-HRChoose it when the part is bent, formed or impact-loaded, or when the part is machined in volume.
T8A-QT300Choose it when strength drives the design.
T8A-HR vs T8A-QT300: 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)
Hardness, Brinell
Hardness, Rockwell B
Hardness, Vickers
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 · Charpy V-Notch Impact (RT) 8 J5.9 ft·lbf
Physical
Density and transition temperatures.
Same in both: Density 7.85 g/cm³0.28 lb/in³ · Melting Point (Solidus) 1,400°C2,552 °F · Liquidus Temperature 1,470°C2,678 °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) 11.5 µm/m·K6.4 µin/in·°F · Latent Heat of Fusion 250 J/g107 BTU/lb · Min Service Temperature -20°C-4 °F
Electrical
Conductivity and insulation.
Same in both: Electrical Conductivity 9.5 % IACS · Electrical Resistivity 1.8×10⁻⁷ Ω·m7.09 µΩ·in
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Same in both: Galvanic Potential (seawater, vs SCE) -0.6 V · Corrosion Resistance 10 / 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 45 / 100 · Polishability 60 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 30 MJ/kg12,898 BTU/lb · Embodied Carbon (primary production) 2.2 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.
T8A-HR vs T8A-QT300 — frequently asked
Is T8A-QT300 stronger than T8A-HR?
Yes. T8A-QT300 has a typical yield strength of 1,650 MPa (239 ksi) against 450 MPa (65.3 ksi) for T8A-HR — about 3.7 times as much. Tensile strength is 1,950 MPa (283 ksi) vs 830 MPa (120 ksi).
Which condition does FabDigit quote by default, HR or QT300?
A is the default T8A condition in the FabDigit quote flow (neither HR nor QT300). 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, T8A-HR or T8A-QT300?
T8A-HR. Its machinability rates fair (42/100) against not recommended (8/100) for T8A-QT300.
Ready to make it?
Upload a CAD file and FabDigit prices the part in T8A-HR and T8A-QT300 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.