Steel SK95-QT300 vs SK95-QT500
Steel · SK95 temper comparison
SK95-QT300 and SK95-QT500 are two conditions of the same steel grade, SK95: QT300 (quenched + tempered 300 °C) versus QT500 (quenched + tempered 500 °C). The chemistry is identical, so every difference below comes from the condition. SK95-QT300 is the stronger of the two: yield strength 1,550 MPa (225 ksi) against 1,100 MPa (160 ksi) for SK95-QT500, about 41% more; tensile strength follows at 1,800 MPa (261 ksi) vs 1,280 MPa (186 ksi). In exchange, SK95-QT500 is the more ductile: elongation 9% versus 3% for SK95-QT300, and SK95-QT300 is harder (545 HB vs 380 HB). SK95-QT500 runs hotter in service (400°C vs 250°C continuous). On the shop floor, SK95-QT500 machines more easily (poor vs not recommended).
SK95-QT300Choose it when strength drives the design.
SK95-QT500Choose it when the part is bent, formed or impact-loaded, or when the part sees heat.
SK95-QT300 vs SK95-QT500: 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)
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 · Hardness, Rockwell B 91 HRB
Physical
Density and transition temperatures.
Same in both: Density 7.83 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.
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.
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 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: Castability 25 / 100 · Brazeability / Solderability 50 / 100 · Polishability 70 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 32 MJ/kg13,758 BTU/lb · Embodied Carbon (primary production) 2.3 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.
SK95-QT300 vs SK95-QT500 — frequently asked
Is SK95-QT300 stronger than SK95-QT500?
Yes. SK95-QT300 has a typical yield strength of 1,550 MPa (225 ksi) against 1,100 MPa (160 ksi) for SK95-QT500 — about 41% more. Tensile strength is 1,800 MPa (261 ksi) vs 1,280 MPa (186 ksi).
Which condition does FabDigit quote by default, QT300 or QT500?
A is the default SK95 condition in the FabDigit quote flow (neither QT300 nor QT500). 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, SK95-QT300 or SK95-QT500?
SK95-QT500. Its machinability rates poor (28/100) against not recommended (12/100) for SK95-QT300.
Ready to make it?
Upload a CAD file and FabDigit prices the part in SK95-QT300 and SK95-QT500 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.