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Steel 27NiCrMoV15-6 vs 34MnB5

Steel · grade comparison

Steel 27NiCrMoV15-6 and 34MnB5 are both steel grades. 27NiCrMoV15-6 is the stronger of the two: yield strength 930 MPa (135 ksi) against 420 MPa (60.9 ksi) for 34MnB5, about 121% more; tensile strength follows at 1,080 MPa (157 ksi) vs 620 MPa (89.9 ksi). 27NiCrMoV15-6 is harder — 330 HB against 185 HB for 34MnB5 — which matters for wear surfaces and threads. 34MnB5 conducts heat better (44 W/m·K vs 34 W/m·K). On the shop floor, 34MnB5 machines more easily (good vs fair), 34MnB5 welds better (good vs poor), and 34MnB5 forms better (good vs poor).

27NiCrMoV15-6Choose it when strength drives the design, or when surface hardness matters.

34MnB5Choose it when the part is machined in volume, or when it will be welded.

27NiCrMoV15-6 vs 34MnB5: properties

27NiCrMoV15-634MnB5

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Bulk Modulus

165 GPa23.9 Msi
160 GPa23.2 Msi

Tensile Strength (Ultimate)

1,080 MPa157 ksi
620 MPa89.9 ksi

Yield Strength (0.2% offset)

930 MPa135 ksi
420 MPa60.9 ksi

Elongation at Break

15%
14%

Reduction in Area

55%
45%

Compressive Strength

940 MPa136 ksi
—

Shear Strength

660 MPa95.7 ksi
400 MPa58 ksi

Fatigue Strength (Endurance Limit)

520 MPa75.4 ksi
280 MPa40.6 ksi

Fracture Toughness (K_IC)

115 MPa·√m105 ksi·√in
55 MPa·√m50.1 ksi·√in

Charpy V-Notch Impact (RT)

60 J44.3 ft·lbf
40 J29.5 ft·lbf

Hardness, Brinell

330 HB
185 HB

Hardness, Rockwell C

35 HRC
—

Hardness, Vickers

345 HV
195 HV

Hardness, Rockwell B

—
89 HRB

Same in both: Elastic (Young's) Modulus 210 GPa30.5 Msi · Shear Modulus 80 GPa11.6 Msi · Poisson's Ratio 0.29

Physical

Density and transition temperatures.

Melting Point (Solidus)

1,425°C2,597 °F
1,420°C2,588 °F

Liquidus Temperature

1,490°C2,714 °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

34 W/m·K19.6 BTU/hr·ft·°F
44 W/m·K25.4 BTU/hr·ft·°F

Specific Heat Capacity

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

Thermal Expansion (CTE, 20–100 °C)

12 µm/m·K6.7 µin/in·°F
12.5 µm/m·K6.9 µin/in·°F

Min Service Temperature

-60°C-76 °F
-40°C-40 °F

Same in both: Latent Heat of Fusion 250 J/g107 BTU/lb · Max Service Temperature (continuous) 400°C752 °F

Electrical

Conductivity and insulation.

Electrical Conductivity

7 % IACS
8 % IACS

Electrical Resistivity

2.5×10⁻⁷ Ω·m9.84 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)

-0.62 V
-0.6 V

Corrosion Resistance

13 / 100
11 / 100

Manufacturability

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

Machinability

38 / 100
55 / 100

Machinability Rating (AISI 1212 = 100 %)

40%
60%

Weldability

25 / 100
55 / 100

Formability (cold)

18 / 100
60 / 100

Polishability

70 / 100
55 / 100

Same in both: Brazeability / Solderability 45 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

31 MJ/kg13,328 BTU/lb
25 MJ/kg10,748 BTU/lb

Embodied Carbon (primary production)

2.3 kg CO₂/kg
2 kg CO₂/kg

Embodied Water

60 L/kg7.2 gal/lb
40 L/kg4.8 gal/lb

Typical Recycled Content

30%
25%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

138 kN·m/kg
79 kN·m/kg

Modulus of Resilience

2,059 kJ/m³
420 kJ/m³

Thermal Diffusivity

9.3 mm²/s
11.9 mm²/s

Thermal Shock Resistance Index

15
10

Same in both: Specific Stiffness (E / density) 26.8 MN·m/kg

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 scale34MnB527NiCrMoV15-6

Manufacturing and finishing

Capability27NiCrMoV15-634MnB5
Sheet metal—Yes
Default condition—CR
Relative cost$$ Standard$$ Standard
Min. machined wall——
Best machined surface——
Black Oxide—Yes
Cerakote—Yes
Chrome Plating—Yes
E-Coating—Yes
Hot-Dip Galvanizing—Yes
Nickel Plating—Yes
PTFE Coating—Yes
Painting—Yes
Powder Coating—Yes
Tin Plating—Yes
Zinc Plating—Yes
Zinc-Flake (Dip-Spin) Coating—Yes
Zinc-Nickel Plating—Yes

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

27NiCrMoV15-6 vs 34MnB5 — frequently asked

Is 27NiCrMoV15-6 stronger than 34MnB5?

Yes. 27NiCrMoV15-6 has a typical yield strength of 930 MPa (135 ksi) against 420 MPa (60.9 ksi) for 34MnB5 — about 121% more. Tensile strength is 1,080 MPa (157 ksi) vs 620 MPa (89.9 ksi).

Which is cheaper, 27NiCrMoV15-6 or 34MnB5?

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

Which is easier to machine, 27NiCrMoV15-6 or 34MnB5?

34MnB5. Its machinability rates good (55/100) against fair (38/100) for 27NiCrMoV15-6; for welding the order is 34MnB5 first (good, 55/100) then 27NiCrMoV15-6 (poor, 25/100).

Ready to make it?

Upload a CAD file and FabDigit prices the part in 27NiCrMoV15-6 and 34MnB5 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.