Steel SNC631-HR vs SNC631 QT-28-32HRC
Steel · SNC631 temper comparison
SNC631-HR and SNC631 QT-28-32HRC are two conditions of the same steel grade, SNC631: HR (hot rolled) versus QT-28-32HRC. The chemistry is identical, so every difference below comes from the condition. SNC631 QT-28-32HRC is the stronger of the two: yield strength 840 MPa (122 ksi) against 470 MPa (68.2 ksi) for SNC631-HR, about 79% more; tensile strength follows at 980 MPa (142 ksi) vs 760 MPa (110 ksi). In exchange, SNC631-HR is the more ductile: elongation 20% versus 17% for SNC631 QT-28-32HRC, and SNC631 QT-28-32HRC is harder (293 HB vs 217 HB). On the shop floor, SNC631-HR welds better (45 vs 35 out of 100).
SNC631-HRChoose it when the part is bent, formed or impact-loaded, or when it will be welded.
SNC631 QT-28-32HRCChoose it when strength drives the design.
SNC631-HR vs SNC631 QT-28-32HRC: 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 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 1,495°C2,723 °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 270 J/g116 BTU/lb · Max Service Temperature (continuous) 400°C752 °F · Min Service Temperature -60°C-76 °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 13 / 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 55 / 100 · Polishability 65 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 32 MJ/kg13,758 BTU/lb · Embodied Carbon (primary production) 2.4 kg CO₂/kg · Embodied Water 65 L/kg7.8 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.
SNC631-HR vs SNC631 QT-28-32HRC — frequently asked
Is SNC631 QT-28-32HRC stronger than SNC631-HR?
Yes. SNC631 QT-28-32HRC has a typical yield strength of 840 MPa (122 ksi) against 470 MPa (68.2 ksi) for SNC631-HR — about 79% more. Tensile strength is 980 MPa (142 ksi) vs 760 MPa (110 ksi).
Which condition does FabDigit quote by default, HR or QT-28-32HRC?
QT is the default SNC631 condition in the FabDigit quote flow (neither HR nor QT-28-32HRC). 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, SNC631-HR or SNC631 QT-28-32HRC?
SNC631-HR. Its machinability rates good (55/100) against fair (48/100) for SNC631 QT-28-32HRC; for welding the order is SNC631-HR first (fair, 45/100) then SNC631 QT-28-32HRC (fair, 35/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in SNC631-HR and SNC631 QT-28-32HRC 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.