Steel C15C +N vs C15C +U
Steel · C15C temper comparison
C15C +N and C15C +U are two conditions of the same steel grade, C15C: +N (normalized) versus +U (hot rolled). The chemistry is identical, so every difference below comes from the condition. C15C +N is the stronger of the two: yield strength 275 MPa (39.9 ksi) against 260 MPa (37.7 ksi) for C15C +U, about 6% more. C15C +N is harder — 132 HV against 125 HV for C15C +U — which matters for wear surfaces and threads.
C15C +NChoose it when strength drives the design, or when surface hardness matters.
C15C +N vs C15C +U: 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
Compressive 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 207 GPa30 Msi · Shear Modulus 80 GPa11.6 Msi · Bulk Modulus 160 GPa23.2 Msi · Poisson's Ratio 0.29 · Reduction in Area 62% · Shear Strength 275 MPa39.9 ksi
Physical
Density and transition temperatures.
Same in both: Density 7.85 g/cm³0.28 lb/in³ · Melting Point (Solidus) 1,465°C2,669 °F · Liquidus Temperature 1,520°C2,768 °F
Thermal
How each material carries heat and how hot it can run.
Same in both: Thermal Conductivity 51 W/m·K29.5 BTU/hr·ft·°F · Specific Heat Capacity 480 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) 350°C662 °F · Min Service Temperature -30°C-22 °F
Electrical
Conductivity and insulation.
Same in both: Electrical Conductivity 10.5 % IACS · Electrical Resistivity 1.65×10⁻⁷ Ω·m6.5 µΩ·in
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Same in both: Galvanic Potential (seawater, vs SCE) -0.61 V · Corrosion Resistance 10 / 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 75 / 100 · Polishability 55 / 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 45 L/kg5.4 gal/lb · Typical Recycled Content 25%
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.
C15C +N vs C15C +U — frequently asked
Is C15C +N stronger than C15C +U?
Yes. C15C +N has a typical yield strength of 275 MPa (39.9 ksi) against 260 MPa (37.7 ksi) for C15C +U — about 6% more. Tensile strength is 430 MPa (62.4 ksi) vs 420 MPa (60.9 ksi).
Which condition does FabDigit quote by default, +N or +U?
+AC+C is the default C15C condition in the FabDigit quote flow (neither +N nor +U). 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, C15C +N or C15C +U?
C15C +N. Its machinability rates good (60/100) against fair (52/100) for C15C +U.
Ready to make it?
Upload a CAD file and FabDigit prices the part in C15C +N and C15C +U 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.