FabDigit

Steel 40MnB vs 10B21 vs 10B22 vs 15B35

Benchmark · 4 materials

Side-by-side benchmark of 4 steel grades.

40MnB vs 10B21 and 2 more: properties

40MnB10B2110B2215B35

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

210 GPa30.5 Msi
205 GPa29.7 Msi
205 GPa29.7 Msi
205 GPa29.7 Msi

Tensile Strength (Ultimate)

1,030 MPa149 ksi
430 MPa62.4 ksi
620 MPa89.9 ksi
730 MPa106 ksi

Yield Strength (0.2% offset)

850 MPa123 ksi
290 MPa42.1 ksi
525 MPa76.1 ksi
620 MPa89.9 ksi

Elongation at Break

12%
30%
13%
13%

Reduction in Area

50%
55%
48%
40%

Compressive Strength

860 MPa125 ksi
620 MPa89.9 ksi

Shear Strength

620 MPa89.9 ksi
275 MPa39.9 ksi
375 MPa54.4 ksi
440 MPa63.8 ksi

Fatigue Strength (Endurance Limit)

470 MPa68.2 ksi
200 MPa29 ksi
280 MPa40.6 ksi
330 MPa47.9 ksi

Fracture Toughness (K_IC)

70 MPa·√m63.7 ksi·√in
90 MPa·√m81.9 ksi·√in
75 MPa·√m68.3 ksi·√in

Charpy V-Notch Impact (RT)

55 J40.6 ft·lbf
65 J47.9 ft·lbf
45 J33.2 ft·lbf
25 J18.4 ft·lbf

Hardness, Brinell

300 HB
126 HB
180 HB
217 HB

Hardness, Rockwell C

31 HRC

Hardness, Vickers

315 HV

Hardness, Rockwell B

71 HRB
89 HRB
96 HRB

Same in both: Shear Modulus 80 GPa11.6 Msi · Bulk Modulus 160 GPa23.2 Msi · Poisson's Ratio 0.29

Physical

Density and transition temperatures.

Melting Point (Solidus)

1,420°C2,588 °F
1,465°C2,669 °F
1,450°C2,642 °F
1,425°C2,597 °F

Liquidus Temperature

1,495°C2,723 °F
1,510°C2,750 °F
1,510°C2,750 °F
1,495°C2,723 °F

Same in both: Density 7.85 g/cm³0.28 lb/in³

Thermal

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

Thermal Conductivity

43 W/m·K24.8 BTU/hr·ft·°F
51.9 W/m·K30 BTU/hr·ft·°F
49 W/m·K28.3 BTU/hr·ft·°F
46 W/m·K26.6 BTU/hr·ft·°F

Specific Heat Capacity

470 J/kg·K0.11 BTU/lb·°F
470 J/kg·K0.11 BTU/lb·°F
470 J/kg·K0.11 BTU/lb·°F
475 J/kg·K0.11 BTU/lb·°F

Thermal Expansion (CTE, 20–100 °C)

12.2 µm/m·K6.8 µin/in·°F
11.7 µm/m·K6.5 µin/in·°F
11.9 µm/m·K6.6 µin/in·°F
11.9 µm/m·K6.6 µin/in·°F

Latent Heat of Fusion

250 J/g107 BTU/lb
247 J/g106 BTU/lb
250 J/g107 BTU/lb
247 J/g106 BTU/lb

Max Service Temperature (continuous)

400°C752 °F
400°C752 °F
350°C662 °F
350°C662 °F

Min Service Temperature

-20°C-4 °F
-30°C-22 °F
-30°C-22 °F
-30°C-22 °F

Electrical

Conductivity and insulation.

Electrical Conductivity

7.8 % IACS
10.8 % IACS
10 % IACS
9.5 % IACS

Electrical Resistivity

2.2×10⁻⁷ Ω·m8.66 µΩ·in
1.6×10⁻⁷ Ω·m6.3 µΩ·in
1.7×10⁻⁷ Ω·m6.69 µΩ·in
1.8×10⁻⁷ Ω·m7.09 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Galvanic Potential (seawater, vs SCE)

-0.62 V
-0.61 V
-0.6 V
-0.61 V

Corrosion Resistance

11 / 100
10 / 100
10 / 100
10 / 100

Manufacturability

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

Machinability

52 / 100
62 / 100
55 / 100
55 / 100

Machinability Rating (AISI 1212 = 100 %)

55%
65%
65%
65%

Weldability

32 / 100
85 / 100
72 / 100
40 / 100

Formability (cold)

35 / 100
82 / 100
85 / 100
55 / 100

Brazeability / Solderability

55 / 100
70 / 100
65 / 100
60 / 100

Polishability

62 / 100
45 / 100
50 / 100
55 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

26 MJ/kg11,178 BTU/lb
25 MJ/kg10,748 BTU/lb
25 MJ/kg10,748 BTU/lb
25 MJ/kg10,748 BTU/lb

Embodied Carbon (primary production)

2 kg CO₂/kg
1.9 kg CO₂/kg
1.9 kg CO₂/kg
1.9 kg CO₂/kg

Typical Recycled Content

25%
30%
30%
30%

Same in both: Embodied Water 40 L/kg4.8 gal/lb

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

131 kN·m/kg
55 kN·m/kg
79 kN·m/kg
93 kN·m/kg

Specific Stiffness (E / density)

26.8 MN·m/kg
26.1 MN·m/kg
26.1 MN·m/kg
26.1 MN·m/kg

Modulus of Resilience

1,720 kJ/m³
205 kJ/m³
672 kJ/m³
938 kJ/m³

Thermal Diffusivity

11.7 mm²/s
14.1 mm²/s
13.3 mm²/s
12.3 mm²/s

Thermal Shock Resistance Index

17
9
12
14

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 scale10B2110B2215B3540MnB

Manufacturing and finishing

Capability40MnB10B2110B2215B35
CNC machiningYes
Sheet metalYes
Default conditionHR
Relative cost$ Budget$ Budget$ Budget$ Budget
Min. machined wall0.8 mm
Best machined surfaceRa 1.6 µm
AlCrNYes
AlTiNYes
Black OxideYes
CVD Al2O3Yes
CVD TiCNYes
CVD TiNYes
CerakoteYes
Chrome PlatingYes
CrNYes
DLCYes
E-CoatingYes
HVOF CoatingYes
Hot-Dip GalvanizingYes
MoS2Yes
Multilayer CVDYes
Nickel PlatingYes
PTFE CoatingYes
PaintingYes

They share 9 finishes: Copper Plating, Electroless Nickel (EN), Epoxy Coating, Gold Plating, Hard Chrome Plating, Manganese Phosphate, Plasma Spray, Silver Plating, Zinc Phosphate.

Ready to make it?

Upload a CAD file and FabDigit prices the part in 40MnB and 10B21 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.