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Steel 40MnB-A vs 40MnB-N

Steel · 40MnB temper comparison

40MnB-A and 40MnB-N are two conditions of the same steel grade, 40MnB: A (solution annealed) versus N (normalized). The chemistry is identical, so every difference below comes from the condition. 40MnB-N is the stronger of the two: yield strength 480 MPa (69.6 ksi) against 350 MPa (50.8 ksi) for 40MnB-A, about 37% more; tensile strength follows at 780 MPa (113 ksi) vs 610 MPa (88.5 ksi). In exchange, 40MnB-A is the more ductile: elongation 21% versus 16% for 40MnB-N, and 40MnB-N is harder (235 HB vs 185 HB).

40MnB-AChoose it when the part is bent, formed or impact-loaded.

40MnB-NChoose it when strength drives the design.

40MnB-A vs 40MnB-N: properties

40MnB-A40MnB-N

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Tensile Strength (Ultimate)

610 MPa88.5 ksi
780 MPa113 ksi

Yield Strength (0.2% offset)

350 MPa50.8 ksi
480 MPa69.6 ksi

Elongation at Break

21%
16%

Reduction in Area

50%
45%

Compressive Strength

860 MPa125 ksi
490 MPa71.1 ksi

Shear Strength

620 MPa89.9 ksi
470 MPa68.2 ksi

Fatigue Strength (Endurance Limit)

280 MPa40.6 ksi
350 MPa50.8 ksi

Fracture Toughness (K_IC)

70 MPa·√m63.7 ksi·√in
85 MPa·√m77.4 ksi·√in

Charpy V-Notch Impact (RT)

45 J33.2 ft·lbf
38 J28 ft·lbf

Hardness, Brinell

185 HB
235 HB

Hardness, Rockwell C

31 HRC
21 HRC

Hardness, Vickers

315 HV
245 HV

Same in both: Elastic (Young's) Modulus 210 GPa30.5 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) 1,420°C2,588 °F · Liquidus Temperature 1,495°C2,723 °F

Thermal

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

Thermal Conductivity

43 W/m·K24.8 BTU/hr·ft·°F
45 W/m·K26 BTU/hr·ft·°F

Max Service Temperature (continuous)

400°C752 °F
425°C797 °F

Same in both: 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 250 J/g107 BTU/lb · Min Service Temperature -20°C-4 °F

Electrical

Conductivity and insulation.

Electrical Conductivity

7.8 % IACS
8 % IACS

Electrical Resistivity

2.2×10⁻⁷ Ω·m8.66 µΩ·in
2.15×10⁻⁷ Ω·m8.46 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Same in both: Galvanic Potential (seawater, vs SCE) -0.62 V · Corrosion Resistance 11 / 100

Manufacturability

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

Machinability

62 / 100
57 / 100

Machinability Rating (AISI 1212 = 100 %)

66%
60%

Formability (cold)

55 / 100
46 / 100

Same in both: Weldability 38 / 100 · Brazeability / Solderability 55 / 100 · Polishability 62 / 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 40 L/kg4.8 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 scale40MnB

40MnB-A vs 40MnB-N — frequently asked

Is 40MnB-N stronger than 40MnB-A?

Yes. 40MnB-N has a typical yield strength of 480 MPa (69.6 ksi) against 350 MPa (50.8 ksi) for 40MnB-A — about 37% more. Tensile strength is 780 MPa (113 ksi) vs 610 MPa (88.5 ksi).

Which condition does FabDigit quote by default, A or N?

QT is the default 40MnB condition in the FabDigit quote flow (neither A nor N). 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, 40MnB-A or 40MnB-N?

40MnB-A, by a small margin. Both rate good for machinability — 62/100 against 57/100 for 40MnB-N.

Ready to make it?

Upload a CAD file and FabDigit prices the part in 40MnB-A and 40MnB-N 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.