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Steel 27SiMn-CD vs 27SiMn N+T

Steel · 27SiMn temper comparison

27SiMn-CD and 27SiMn N+T are two conditions of the same steel grade, 27SiMn: CD (cold drawn) versus N+T (normalized and tempered). The chemistry is identical, so every difference below comes from the condition. 27SiMn-CD is the stronger of the two: yield strength 700 MPa (102 ksi) against 480 MPa (69.6 ksi) for 27SiMn N+T, about 46% more; tensile strength follows at 900 MPa (131 ksi) vs 760 MPa (110 ksi). In exchange, 27SiMn N+T is the more ductile: elongation 19% versus 12% for 27SiMn-CD, and 27SiMn-CD is harder (270 HB vs 225 HB). 27SiMn N+T runs hotter in service (420°C vs 300°C continuous). On the shop floor, 27SiMn N+T welds better (fair vs poor).

27SiMn-CDChoose it when strength drives the design.

27SiMn N+TChoose it when the part is bent, formed or impact-loaded, or when the part sees heat.

27SiMn-CD vs 27SiMn N+T: properties

27SiMn-CD27SiMn N+T

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Tensile Strength (Ultimate)

900 MPa131 ksi
760 MPa110 ksi

Yield Strength (0.2% offset)

700 MPa102 ksi
480 MPa69.6 ksi

Elongation at Break

12%
19%

Reduction in Area

40%
50%

Shear Strength

545 MPa79 ksi
465 MPa67.4 ksi

Fatigue Strength (Endurance Limit)

400 MPa58 ksi
345 MPa50 ksi

Fracture Toughness (K_IC)

60 MPa·√m54.6 ksi·√in
95 MPa·√m86.5 ksi·√in

Charpy V-Notch Impact (RT)

30 J22.1 ft·lbf
55 J40.6 ft·lbf

Hardness, Brinell

270 HB
225 HB

Hardness, Rockwell C

26 HRC
20 HRC

Hardness, Vickers

285 HV
235 HV

Same in both: Elastic (Young's) Modulus 210 GPa30.5 Msi · Shear Modulus 81 GPa11.7 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) 1,420°C2,588 °F · Liquidus Temperature 1,490°C2,714 °F

Thermal

How each material carries heat and how hot it can run.

Thermal Conductivity

40 W/m·K23.1 BTU/hr·ft·°F
41 W/m·K23.7 BTU/hr·ft·°F

Max Service Temperature (continuous)

300°C572 °F
420°C788 °F

Same in both: Specific Heat Capacity 470 J/kg·K0.11 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 12.3 µm/m·K6.8 µin/in·°F · Latent Heat of Fusion 270 J/g116 BTU/lb · Min Service Temperature -40°C-40 °F

Electrical

Conductivity and insulation.

Electrical Conductivity

6.8 % IACS
7 % IACS

Electrical Resistivity

2.55×10⁻⁷ Ω·m10 µΩ·in
2.5×10⁻⁷ Ω·m9.84 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Same in both: Galvanic Potential (seawater, vs SCE) -0.61 V · Corrosion Resistance 11 / 100

Manufacturability

FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.

Machinability

52 / 100
55 / 100

Machinability Rating (AISI 1212 = 100 %)

55%
58%

Weldability

30 / 100
45 / 100

Formability (cold)

20 / 100
42 / 100

Same in both: Brazeability / Solderability 45 / 100 · Polishability 65 / 100

Sustainability

Primary-production footprint per kilogram.

Same in both: Embodied Energy (primary production) 26 MJ/kg11,178 BTU/lb · Embodied Carbon (primary production) 2 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.

2005001,0002,0007.588.5Density (g/cm³)Yield strength (MPa) — log scale27SiMn

27SiMn-CD vs 27SiMn N+T — frequently asked

Is 27SiMn-CD stronger than 27SiMn N+T?

Yes. 27SiMn-CD has a typical yield strength of 700 MPa (102 ksi) against 480 MPa (69.6 ksi) for 27SiMn N+T — about 46% more. Tensile strength is 900 MPa (131 ksi) vs 760 MPa (110 ksi).

Which condition does FabDigit quote by default, CD or N+T?

QT is the default 27SiMn condition in the FabDigit quote flow (neither CD nor N+T). 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 welds better, 27SiMn-CD or 27SiMn N+T?

27SiMn N+T. Its weldability rates fair (45/100) against poor (30/100) for 27SiMn-CD.

Ready to make it?

Upload a CAD file and FabDigit prices the part in 27SiMn-CD and 27SiMn N+T 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.