Steel 4027-QT315 vs 4027-QT540
Steel · 4027 temper comparison
4027-QT315 and 4027-QT540 are two conditions of the same steel grade, 4027: QT315 (Q&T 315 °C) versus QT540 (Q&T 540 °C). The chemistry is identical, so every difference below comes from the condition. 4027-QT315 is the stronger of the two: yield strength 760 MPa (110 ksi) against 570 MPa (82.7 ksi) for 4027-QT540, about 33% more; tensile strength follows at 950 MPa (138 ksi) vs 720 MPa (104 ksi). In exchange, 4027-QT540 is the more ductile: elongation 22% versus 15% for 4027-QT315, and 4027-QT315 is harder (285 HB vs 212 HB). 4027-QT540 runs hotter in service (425°C vs 250°C continuous). On the shop floor, 4027-QT540 machines more easily (good vs fair) and 4027-QT540 welds better (52 vs 42 out of 100).
4027-QT315Choose it when strength drives the design.
4027-QT540Choose it when the part is bent, formed or impact-loaded, or when the part sees heat.
4027-QT315 vs 4027-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
Compressive Strength
Shear Strength
Fatigue Strength (Endurance Limit)
Fracture Toughness (K_IC)
Charpy V-Notch Impact (RT)
Hardness, Brinell
Hardness, Rockwell B
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
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 1,500°C2,732 °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) 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.
Electrical Conductivity
Electrical Resistivity
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Same in both: Galvanic Potential (seawater, vs SCE) -0.61 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 %)
Weldability
Formability (cold)
Same in both: Castability 40 / 100 · Brazeability / Solderability 70 / 100 · Polishability 60 / 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.
4027-QT315 vs 4027-QT540 — frequently asked
Is 4027-QT315 stronger than 4027-QT540?
Yes. 4027-QT315 has a typical yield strength of 760 MPa (110 ksi) against 570 MPa (82.7 ksi) for 4027-QT540 — about 33% more. Tensile strength is 950 MPa (138 ksi) vs 720 MPa (104 ksi).
Which condition does FabDigit quote by default, QT315 or QT540?
A is the default 4027 condition in the FabDigit quote flow (neither QT315 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, 4027-QT315 or 4027-QT540?
4027-QT540. Its machinability rates good (55/100) against fair (42/100) for 4027-QT315; for welding the order is 4027-QT540 first (fair, 52/100) then 4027-QT315 (fair, 42/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in 4027-QT315 and 4027-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.