Steel 1548-HR vs 1548 QT40-45HRC
Steel · 1548 temper comparison
1548-HR and 1548 QT40-45HRC are two conditions of the same steel grade, 1548: HR (hot rolled) versus QT40-45HRC. The chemistry is identical, so every difference below comes from the condition. 1548 QT40-45HRC is the stronger of the two: yield strength 1,180 MPa (171 ksi) against 365 MPa (52.9 ksi) for 1548-HR, about 3.2 times as much; tensile strength follows at 1,350 MPa (196 ksi) vs 660 MPa (95.7 ksi). 1548 QT40-45HRC is harder — 400 HB against 197 HB for 1548-HR — which matters for wear surfaces and threads. On the shop floor, 1548-HR machines more easily (fair vs poor) and 1548-HR welds better (poor vs not recommended).
1548-HRChoose it when the part is machined in volume, or when it will be welded.
1548 QT40-45HRCChoose it when strength drives the design, or when surface hardness matters.
1548-HR vs 1548 QT40-45HRC: 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)
Fracture Toughness (K_IC)
Hardness, Brinell
Hardness, Vickers
Same in both: Elastic (Young's) Modulus 200 GPa29 Msi · Shear Modulus 80 GPa11.6 Msi · Bulk Modulus 160 GPa23.2 Msi · Poisson's Ratio 0.29 · Compressive Strength 365 MPa52.9 ksi · Shear Strength 400 MPa58 ksi · Charpy V-Notch Impact (RT) 20 J14.8 ft·lbf · Hardness, Rockwell B 92 HRB
Physical
Density and transition temperatures.
Same in both: Density 7.85 g/cm³0.28 lb/in³ · Melting Point (Solidus) 1,420°C2,588 °F · Liquidus Temperature 1,480°C2,696 °F
Thermal
How each material carries heat and how hot it can run.
Same in both: Thermal Conductivity 49 W/m·K28.3 BTU/hr·ft·°F · Specific Heat Capacity 470 J/kg·K0.11 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 11.7 µm/m·K6.5 µin/in·°F · Latent Heat of Fusion 260 J/g112 BTU/lb · Max Service Temperature (continuous) 400°C752 °F · Min Service Temperature -30°C-22 °F
Electrical
Conductivity and insulation.
Same in both: Electrical Conductivity 10.5 % IACS · Electrical Resistivity 1.65×10⁻⁷ Ω·m6.5 µΩ·in
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Same in both: Galvanic Potential (seawater, vs SCE) -0.65 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
Same in both: Formability (cold) 25 / 100 · Brazeability / Solderability 60 / 100 · Polishability 55 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 25 MJ/kg10,748 BTU/lb · Embodied Carbon (primary production) 1.9 kg CO₂/kg · Embodied Water 45 L/kg5.4 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.
1548-HR vs 1548 QT40-45HRC — frequently asked
Is 1548 QT40-45HRC stronger than 1548-HR?
Yes. 1548 QT40-45HRC has a typical yield strength of 1,180 MPa (171 ksi) against 365 MPa (52.9 ksi) for 1548-HR — about 3.2 times as much. Tensile strength is 1,350 MPa (196 ksi) vs 660 MPa (95.7 ksi).
Which condition does FabDigit quote by default, HR or QT40-45HRC?
HR is the default 1548 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, 1548-HR or 1548 QT40-45HRC?
1548-HR. Its machinability rates fair (45/100) against poor (25/100) for 1548 QT40-45HRC; for welding the order is 1548-HR first (poor, 30/100) then 1548 QT40-45HRC (not recommended, 12/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in 1548-HR and 1548 QT40-45HRC 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.