Steel SCMn3 Q+T vs SCMn3-SR
Steel · SCMn3 temper comparison
SCMn3 Q+T and SCMn3-SR are two conditions of the same steel grade, SCMn3: Q+T (quenched and tempered) versus SR (stress relieved). The chemistry is identical, so every difference below comes from the condition. SCMn3 Q+T is the stronger of the two: yield strength 620 MPa (89.9 ksi) against 420 MPa (60.9 ksi) for SCMn3-SR, about 48% more; tensile strength follows at 830 MPa (120 ksi) vs 680 MPa (98.6 ksi). In exchange, SCMn3-SR is the more ductile: elongation 17% versus 15% for SCMn3 Q+T, and SCMn3 Q+T is harder (255 HB vs 200 HB).
SCMn3 Q+TChoose it when strength drives the design.
SCMn3-SRChoose it when the part is bent, formed or impact-loaded.
SCMn3 Q+T vs SCMn3-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 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) 1,425°C2,597 °F · Liquidus Temperature 1,490°C2,714 °F
Thermal
How each material carries heat and how hot it can run.
Same in both: Thermal Conductivity 44 W/m·K25.4 BTU/hr·ft·°F · 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 270 J/g116 BTU/lb · Max Service Temperature (continuous) 400°C752 °F · Min Service Temperature -20°C-4 °F
Electrical
Conductivity and insulation.
Same in both: Electrical Conductivity 8 % IACS · Electrical Resistivity 2.1×10⁻⁷ Ω·m8.27 µΩ·in
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
Same in both: Formability (cold) 15 / 100 · Castability 70 / 100 · Brazeability / Solderability 55 / 100 · Polishability 50 / 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 60 L/kg7.2 gal/lb · Typical Recycled Content 85%
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.
SCMn3 Q+T vs SCMn3-SR — frequently asked
Is SCMn3 Q+T stronger than SCMn3-SR?
Yes. SCMn3 Q+T has a typical yield strength of 620 MPa (89.9 ksi) against 420 MPa (60.9 ksi) for SCMn3-SR — about 48% more. Tensile strength is 830 MPa (120 ksi) vs 680 MPa (98.6 ksi).
Which condition does FabDigit quote by default, Q+T or SR?
N+T is the default SCMn3 condition in the FabDigit quote flow (neither Q+T 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, SCMn3 Q+T or SCMn3-SR?
SCMn3-SR, by a small margin. Both rate fair for machinability — 50/100 against 42/100 for SCMn3 Q+T; for welding the order is SCMn3-SR first (fair, 50/100) then SCMn3 Q+T (fair, 45/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in SCMn3 Q+T and SCMn3-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.