Steel 50B50-QT425 vs 50B50-QT540
Steel · 50B50 temper comparison
50B50-QT425 and 50B50-QT540 are two conditions of the same steel grade, 50B50: QT425 versus QT540. The chemistry is identical, so every difference below comes from the condition. 50B50-QT425 is the stronger of the two: yield strength 1,350 MPa (196 ksi) against 1,060 MPa (154 ksi) for 50B50-QT540, about 27% more; tensile strength follows at 1,450 MPa (210 ksi) vs 1,150 MPa (167 ksi). In exchange, 50B50-QT540 is the more ductile: elongation 15% versus 11% for 50B50-QT425, and 50B50-QT425 is harder (405 HB vs 340 HB). 50B50-QT540 runs hotter in service (480°C vs 370°C continuous).
50B50-QT425Choose it when strength drives the design.
50B50-QT540Choose it when the part is bent, formed or impact-loaded, or when the part sees heat.
50B50-QT425 vs 50B50-QT540: 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)
Charpy V-Notch Impact (RT)
Hardness, Brinell
Hardness, Vickers
Same in both: Elastic (Young's) Modulus 205 GPa29.7 Msi · Shear Modulus 80 GPa11.6 Msi · Bulk Modulus 160 GPa23.2 Msi · Poisson's Ratio 0.29 · Compressive Strength 380 MPa55.1 ksi · Shear Strength 430 MPa62.4 ksi · 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 1,490°C2,714 °F
Thermal
How each material carries heat and how hot it can run.
Max Service Temperature (continuous)
Same in both: Thermal Conductivity 46 W/m·K26.6 BTU/hr·ft·°F · Specific Heat Capacity 470 J/kg·K0.11 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 12.3 µm/m·K6.8 µin/in·°F · Latent Heat of Fusion 250 J/g107 BTU/lb · Min Service Temperature -30°C-22 °F
Electrical
Conductivity and insulation.
Same in both: Electrical Conductivity 8 % IACS · Electrical Resistivity 2.2×10⁻⁷ Ω·m8.66 µΩ·in
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Same in both: Galvanic Potential (seawater, vs SCE) -0.6 V · Corrosion Resistance 12 / 100
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Machinability Rating (AISI 1212 = 100 %)
Same in both: Weldability 25 / 100 · Formability (cold) 45 / 100 · Brazeability / Solderability 55 / 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 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.
50B50-QT425 vs 50B50-QT540 — frequently asked
Is 50B50-QT425 stronger than 50B50-QT540?
Yes. 50B50-QT425 has a typical yield strength of 1,350 MPa (196 ksi) against 1,060 MPa (154 ksi) for 50B50-QT540 — about 27% more. Tensile strength is 1,450 MPa (210 ksi) vs 1,150 MPa (167 ksi).
Which condition does FabDigit quote by default, QT425 or QT540?
A is the default 50B50 condition in the FabDigit quote flow (neither QT425 nor QT540). 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, 50B50-QT425 or 50B50-QT540?
50B50-QT540. Its machinability rates fair (36/100) against poor (28/100) for 50B50-QT425.
Ready to make it?
Upload a CAD file and FabDigit prices the part in 50B50-QT425 and 50B50-QT540 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.