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Steel 15B35 vs 27MnCrB5-2

Steel · grade comparison

Steel 15B35 and 27MnCrB5-2 are both steel grades. 27MnCrB5-2 is the stronger of the two: yield strength 980 MPa (142 ksi) against 620 MPa (89.9 ksi) for 15B35, about 58% more; tensile strength follows at 1,200 MPa (174 ksi) vs 730 MPa (106 ksi). 27MnCrB5-2 is harder — 360 HB against 217 HB for 15B35 — which matters for wear surfaces and threads. 15B35 runs hotter in service (350°C vs 250°C continuous) and 15B35 conducts electricity better (9.5 % IACS vs 7.8 % IACS). On the shop floor, 15B35 machines more easily (good vs fair) and 15B35 forms better (good vs poor).

15B35Choose it when the part sees heat, or when the part is machined in volume.

27MnCrB5-2Choose it when strength drives the design, or when surface hardness matters.

15B35 vs 27MnCrB5-2: properties

15B3527MnCrB5-2

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

205 GPa29.7 Msi
210 GPa30.5 Msi

Tensile Strength (Ultimate)

730 MPa106 ksi
1,200 MPa174 ksi

Yield Strength (0.2% offset)

620 MPa89.9 ksi
980 MPa142 ksi

Elongation at Break

13%
12%

Reduction in Area

40%
45%

Compressive Strength

620 MPa89.9 ksi
1,200 MPa174 ksi

Shear Strength

440 MPa63.8 ksi
720 MPa104 ksi

Fatigue Strength (Endurance Limit)

330 MPa47.9 ksi
520 MPa75.4 ksi

Charpy V-Notch Impact (RT)

25 J18.4 ft·lbf
45 J33.2 ft·lbf

Hardness, Brinell

217 HB
360 HB

Hardness, Rockwell B

96 HRB
—

Fracture Toughness (K_IC)

—
70 MPa·√m63.7 ksi·√in

Hardness, Rockwell C

—
38 HRC

Hardness, Vickers

—
380 HV

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.

Liquidus Temperature

1,495°C2,723 °F
1,490°C2,714 °F

Same in both: Density 7.85 g/cm³0.28 lb/in³ · Melting Point (Solidus) 1,425°C2,597 °F

Thermal

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

Thermal Conductivity

46 W/m·K26.6 BTU/hr·ft·°F
44 W/m·K25.4 BTU/hr·ft·°F

Specific Heat Capacity

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

Thermal Expansion (CTE, 20–100 °C)

11.9 µm/m·K6.6 µin/in·°F
11.8 µm/m·K6.6 µin/in·°F

Latent Heat of Fusion

247 J/g106 BTU/lb
270 J/g116 BTU/lb

Max Service Temperature (continuous)

350°C662 °F
250°C482 °F

Min Service Temperature

-30°C-22 °F
-40°C-40 °F

Electrical

Conductivity and insulation.

Electrical Conductivity

9.5 % IACS
7.8 % IACS

Electrical Resistivity

1.8×10⁻⁷ Ω·m7.09 µΩ·in
2.2×10⁻⁷ Ω·m8.66 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Galvanic Potential (seawater, vs SCE)

-0.61 V
-0.65 V

Corrosion Resistance

10 / 100
12 / 100

Manufacturability

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

Machinability

55 / 100
42 / 100

Machinability Rating (AISI 1212 = 100 %)

65%
45%

Weldability

40 / 100
35 / 100

Formability (cold)

55 / 100
25 / 100

Brazeability / Solderability

60 / 100
55 / 100

Polishability

55 / 100
65 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

25 MJ/kg10,748 BTU/lb
27 MJ/kg11,608 BTU/lb

Embodied Carbon (primary production)

1.9 kg CO₂/kg
2.1 kg CO₂/kg

Embodied Water

40 L/kg4.8 gal/lb
45 L/kg5.4 gal/lb

Typical Recycled Content

30%
25%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

93 kN·m/kg
153 kN·m/kg

Specific Stiffness (E / density)

26.1 MN·m/kg
26.8 MN·m/kg

Modulus of Resilience

938 kJ/m³
2,287 kJ/m³

Thermal Diffusivity

12.3 mm²/s
11.9 mm²/s

Thermal Shock Resistance Index

14
21

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 scale15B3527MnCrB5-2

Manufacturing and finishing

Capability15B3527MnCrB5-2
Default condition——
Relative cost$ Budget$ Budget
Min. machined wall——
Best machined surface——

Both take the same 9 finishes: Copper Plating, Electroless Nickel (EN), Epoxy Coating, Gold Plating, Hard Chrome Plating, Manganese Phosphate, Plasma Spray, Silver Plating, Zinc Phosphate.

15B35 vs 27MnCrB5-2 — frequently asked

Is 27MnCrB5-2 stronger than 15B35?

Yes. 27MnCrB5-2 has a typical yield strength of 980 MPa (142 ksi) against 620 MPa (89.9 ksi) for 15B35 — about 58% more. Tensile strength is 1,200 MPa (174 ksi) vs 730 MPa (106 ksi).

Which is cheaper, 15B35 or 27MnCrB5-2?

Both sit in the same relative cost tier ($, budget); the part price will be decided by machining time, tolerance and quantity rather than by the material.

Which is easier to machine, 15B35 or 27MnCrB5-2?

15B35. Its machinability rates good (55/100) against fair (42/100) for 27MnCrB5-2; for welding the order is 15B35 first (fair, 40/100) then 27MnCrB5-2 (fair, 35/100).

Ready to make it?

Upload a CAD file and FabDigit prices the part in 15B35 and 27MnCrB5-2 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.