Steel SKD1 QT58-60 vs SKD1-SR
Steel · SKD1 temper comparison
SKD1 QT58-60 and SKD1-SR are two conditions of the same steel grade, SKD1: QT58-60 (hardened & tempered 58–60 HRC) versus SR (stress relieved). The chemistry is identical, so every difference below comes from the condition. SKD1 QT58-60 is the stronger of the two: tensile strength 1,950 MPa (283 ksi) against 790 MPa (115 ksi) for SKD1-SR, about 147% more. SKD1 QT58-60 is harder — 59 HRC against 23 HRC for SKD1-SR — which matters for wear surfaces and threads. SKD1 QT58-60 runs hotter in service (250°C vs 200°C continuous). On the shop floor, SKD1-SR machines more easily (poor vs not recommended).
SKD1 QT58-60Choose it when strength drives the design, or when surface hardness matters.
SKD1-SRChoose it when the part is machined in volume.
SKD1 QT58-60 vs SKD1-SR: 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 C
Hardness, Vickers
Same in both: Elastic (Young's) Modulus 210 GPa30.5 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 7.7 g/cm³0.28 lb/in³ · Melting Point (Solidus) 1,270°C2,318 °F · Liquidus Temperature 1,400°C2,552 °F
Thermal
How each material carries heat and how hot it can run.
Max Service Temperature (continuous)
Same in both: Thermal Conductivity 20 W/m·K11.6 BTU/hr·ft·°F · Specific Heat Capacity 460 J/kg·K0.11 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 10.8 µm/m·K6 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 2.7 % IACS · Electrical Resistivity 6.5×10⁻⁷ Ω·m25.6 µΩ·in
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Same in both: Galvanic Potential (seawater, vs SCE) -0.4 V · Corrosion Resistance 25 / 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 35 / 100 · Polishability 60 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 34 MJ/kg14,617 BTU/lb · Embodied Carbon (primary production) 2.6 kg CO₂/kg · Embodied Water 60 L/kg7.2 gal/lb · Typical Recycled Content 40%
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.
SKD1 QT58-60 vs SKD1-SR — frequently asked
Is SKD1 QT58-60 stronger than SKD1-SR?
Yes. SKD1 QT58-60 has a typical tensile strength of 1,950 MPa (283 ksi) against 790 MPa (115 ksi) for SKD1-SR — about 147% more.
Which condition does FabDigit quote by default, QT58-60 or SR?
ANN is the default SKD1 condition in the FabDigit quote flow (neither QT58-60 nor SR). 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, SKD1 QT58-60 or SKD1-SR?
SKD1-SR. Its machinability rates poor (27/100) against not recommended (8/100) for SKD1 QT58-60.
Ready to make it?
Upload a CAD file and FabDigit prices the part in SKD1 QT58-60 and SKD1-SR 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.