Steel SNC631-CD vs SNC631-HR
Steel · SNC631 temper comparison
SNC631-CD and SNC631-HR are two conditions of the same steel grade, SNC631: CD (cold drawn) versus HR (hot rolled). The chemistry is identical, so every difference below comes from the condition. SNC631-CD is the stronger of the two: yield strength 660 MPa (95.7 ksi) against 470 MPa (68.2 ksi) for SNC631-HR, about 40% more; tensile strength follows at 800 MPa (116 ksi) vs 760 MPa (110 ksi). In exchange, SNC631-HR is the more ductile: elongation 20% versus 12% for SNC631-CD, and SNC631-CD is harder (235 HB vs 217 HB). On the shop floor, SNC631-HR welds better (45 vs 35 out of 100).
SNC631-CDChoose it when strength drives the design.
SNC631-HRChoose it when the part is bent, formed or impact-loaded, or when it will be welded.
SNC631-CD vs SNC631-HR: 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-CD vs SNC631-HR — frequently asked
Is SNC631-CD stronger than SNC631-HR?
Yes. SNC631-CD has a typical yield strength of 660 MPa (95.7 ksi) against 470 MPa (68.2 ksi) for SNC631-HR — about 40% more. Tensile strength is 800 MPa (116 ksi) vs 760 MPa (110 ksi).
Which condition does FabDigit quote by default, CD or HR?
QT is the default SNC631 condition in the FabDigit quote flow (neither CD nor HR). 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-CD or SNC631-HR?
SNC631-CD, by a small margin. Both rate good for machinability — 60/100 against 55/100 for SNC631-HR; for welding the order is SNC631-HR first (fair, 45/100) then SNC631-CD (fair, 35/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in SNC631-CD and SNC631-HR 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.