Steel 61SiCr7 +QT vs 61SiCr7 +S
Steel · 61SiCr7 temper comparison
61SiCr7 +QT and 61SiCr7 +S are two conditions of the same steel grade, 61SiCr7: +QT (quenched and tempered) versus +S (treated for high shearability). The chemistry is identical, so every difference below comes from the condition. 61SiCr7 +QT is the stronger of the two: yield strength 1,550 MPa (225 ksi) against 470 MPa (68.2 ksi) for 61SiCr7 +S, about 3.3 times as much; tensile strength follows at 1,750 MPa (254 ksi) vs 780 MPa (113 ksi). In exchange, 61SiCr7 +S is the more ductile: elongation 17% versus 8% for 61SiCr7 +QT, and 61SiCr7 +QT is harder (460 HB vs 225 HB). On the shop floor, 61SiCr7 +S machines more easily (fair vs poor).
61SiCr7 +QTChoose it when strength drives the design.
61SiCr7 +SChoose it when the part is bent, formed or impact-loaded, or when the part is machined in volume.
61SiCr7 +QT vs 61SiCr7 +S: 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 200 GPa29 Msi · Shear Modulus 78.5 GPa11.4 Msi · Bulk Modulus 160 GPa23.2 Msi · Poisson's Ratio 0.29
Physical
Density and transition temperatures.
Same in both: Density 7.8 g/cm³0.28 lb/in³ · Melting Point (Solidus) 1,420°C2,588 °F · Liquidus Temperature 1,470°C2,678 °F
Thermal
How each material carries heat and how hot it can run.
Thermal Conductivity
Same in both: Specific Heat Capacity 470 J/kg·K0.11 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 12 µm/m·K6.7 µin/in·°F · Latent Heat of Fusion 250 J/g107 BTU/lb · Max Service Temperature (continuous) 250°C482 °F · Min Service Temperature -50°C-58 °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) -0.6 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 %)
Weldability
Formability (cold)
Same in both: Brazeability / Solderability 30 / 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) 2.3 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.
61SiCr7 +QT vs 61SiCr7 +S — frequently asked
Is 61SiCr7 +QT stronger than 61SiCr7 +S?
Yes. 61SiCr7 +QT has a typical yield strength of 1,550 MPa (225 ksi) against 470 MPa (68.2 ksi) for 61SiCr7 +S — about 3.3 times as much. Tensile strength is 1,750 MPa (254 ksi) vs 780 MPa (113 ksi).
Which condition does FabDigit quote by default, +QT or +S?
+QT is the default 61SiCr7 condition in the FabDigit quote flow. 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, 61SiCr7 +QT or 61SiCr7 +S?
61SiCr7 +S. Its machinability rates fair (54/100) against poor (25/100) for 61SiCr7 +QT; for welding the order is 61SiCr7 +S first (poor, 20/100) then 61SiCr7 +QT (poor, 15/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in 61SiCr7 +QT and 61SiCr7 +S 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.