Steel 4047-QT205 vs 4047-QT540
Steel · 4047 temper comparison
4047-QT205 and 4047-QT540 are two conditions of the same steel grade, 4047: QT205 (Q&T 205 °C) versus QT540 (Q&T 540 °C). The chemistry is identical, so every difference below comes from the condition. 4047-QT205 is the stronger of the two: yield strength 1,450 MPa (210 ksi) against 950 MPa (138 ksi) for 4047-QT540, about 53% more; tensile strength follows at 1,830 MPa (265 ksi) vs 1,050 MPa (152 ksi). In exchange, 4047-QT540 is the more ductile: elongation 18% versus 9% for 4047-QT205, and 4047-QT205 is harder (500 HB vs 310 HB). 4047-QT540 runs hotter in service (425°C vs 150°C continuous). On the shop floor, 4047-QT540 machines more easily (fair vs poor) and 4047-QT540 welds better (poor vs not recommended).
4047-QT205Choose it when strength drives the design.
4047-QT540Choose it when the part is bent, formed or impact-loaded, or when the part sees heat.
4047-QT205 vs 4047-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
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 205 GPa29.7 Msi · Shear Modulus 80 GPa11.6 Msi · Bulk Modulus 160 GPa23.2 Msi · Poisson's Ratio 0.29 · Compressive Strength 400 MPa58 ksi · Hardness, Rockwell B 90 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 43 W/m·K24.8 BTU/hr·ft·°F · Specific Heat Capacity 475 J/kg·K0.11 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 12.2 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 7.8 % 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) -0.61 V · Corrosion Resistance 11 / 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) 35 / 100 · Brazeability / Solderability 55 / 100 · Polishability 60 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 29 MJ/kg12,468 BTU/lb · Embodied Carbon (primary production) 2 kg CO₂/kg · Embodied Water 50 L/kg6 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.
4047-QT205 vs 4047-QT540 — frequently asked
Is 4047-QT205 stronger than 4047-QT540?
Yes. 4047-QT205 has a typical yield strength of 1,450 MPa (210 ksi) against 950 MPa (138 ksi) for 4047-QT540 — about 53% more. Tensile strength is 1,830 MPa (265 ksi) vs 1,050 MPa (152 ksi).
Which condition does FabDigit quote by default, QT205 or QT540?
A is the default 4047 condition in the FabDigit quote flow (neither QT205 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, 4047-QT205 or 4047-QT540?
4047-QT540. Its machinability rates fair (45/100) against poor (18/100) for 4047-QT205; for welding the order is 4047-QT540 first (poor, 28/100) then 4047-QT205 (not recommended, 12/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in 4047-QT205 and 4047-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.