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Steel 28NiCrMoV8-5 vs 34MnB5

Steel · grade comparison

Steel 28NiCrMoV8-5 and 34MnB5 are both steel grades. 28NiCrMoV8-5 is the stronger of the two: yield strength 720 MPa (104 ksi) against 420 MPa (60.9 ksi) for 34MnB5, about 71% more; tensile strength follows at 880 MPa (128 ksi) vs 620 MPa (89.9 ksi). 28NiCrMoV8-5 is the more ductile: elongation 16% versus 14% for 34MnB5, and 28NiCrMoV8-5 is harder (270 HB vs 185 HB). 34MnB5 conducts heat better (44 W/m·K vs 36 W/m·K). On the shop floor, 34MnB5 machines more easily (good vs fair) and 34MnB5 welds better (good vs poor).

28NiCrMoV8-5Choose it when strength drives the design, or when the part is bent, formed or impact-loaded.

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

28NiCrMoV8-5 vs 34MnB5: properties

28NiCrMoV8-534MnB5

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Shear Modulus

81 GPa11.7 Msi
80 GPa11.6 Msi

Bulk Modulus

165 GPa23.9 Msi
160 GPa23.2 Msi

Tensile Strength (Ultimate)

880 MPa128 ksi
620 MPa89.9 ksi

Yield Strength (0.2% offset)

720 MPa104 ksi
420 MPa60.9 ksi

Elongation at Break

16%
14%

Reduction in Area

52%
45%

Compressive Strength

730 MPa106 ksi
—

Shear Strength

540 MPa78.3 ksi
400 MPa58 ksi

Fatigue Strength (Endurance Limit)

420 MPa60.9 ksi
280 MPa40.6 ksi

Fracture Toughness (K_IC)

130 MPa·√m118 ksi·√in
55 MPa·√m50.1 ksi·√in

Charpy V-Notch Impact (RT)

70 J51.6 ft·lbf
40 J29.5 ft·lbf

Hardness, Brinell

270 HB
185 HB

Hardness, Rockwell C

27 HRC
—

Hardness, Vickers

285 HV
195 HV

Hardness, Rockwell B

—
89 HRB

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

Physical

Density and transition temperatures.

Density

7.83 g/cm³0.28 lb/in³
7.85 g/cm³0.28 lb/in³

Liquidus Temperature

1,490°C2,714 °F
1,495°C2,723 °F

Same in both: Melting Point (Solidus) 1,420°C2,588 °F

Thermal

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

Thermal Conductivity

36 W/m·K20.8 BTU/hr·ft·°F
44 W/m·K25.4 BTU/hr·ft·°F

Specific Heat Capacity

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

Thermal Expansion (CTE, 20–100 °C)

12.3 µm/m·K6.8 µin/in·°F
12.5 µm/m·K6.9 µin/in·°F

Latent Heat of Fusion

270 J/g116 BTU/lb
250 J/g107 BTU/lb

Min Service Temperature

-30°C-22 °F
-40°C-40 °F

Same in both: Max Service Temperature (continuous) 400°C752 °F

Electrical

Conductivity and insulation.

Electrical Conductivity

7.5 % IACS
8 % IACS

Electrical Resistivity

2.3×10⁻⁷ Ω·m9.06 µΩ·in
2.2×10⁻⁷ Ω·m8.66 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Corrosion Resistance

13 / 100
11 / 100

Same in both: Galvanic Potential (seawater, vs SCE) -0.6 V

Manufacturability

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

Machinability

45 / 100
55 / 100

Machinability Rating (AISI 1212 = 100 %)

50%
60%

Weldability

30 / 100
55 / 100

Formability (cold)

20 / 100
60 / 100

Brazeability / Solderability

40 / 100
45 / 100

Polishability

70 / 100
55 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

34 MJ/kg14,617 BTU/lb
25 MJ/kg10,748 BTU/lb

Embodied Carbon (primary production)

2.4 kg CO₂/kg
2 kg CO₂/kg

Embodied Water

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

Same in both: Typical Recycled Content 25%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

112 kN·m/kg
79 kN·m/kg

Modulus of Resilience

1,234 kJ/m³
420 kJ/m³

Thermal Diffusivity

10 mm²/s
11.9 mm²/s

Thermal Shock Resistance Index

12
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 scale34MnB528NiCrMoV8-5

Manufacturing and finishing

Capability28NiCrMoV8-534MnB5
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.

28NiCrMoV8-5 vs 34MnB5 — frequently asked

Is 28NiCrMoV8-5 stronger than 34MnB5?

Yes. 28NiCrMoV8-5 has a typical yield strength of 720 MPa (104 ksi) against 420 MPa (60.9 ksi) for 34MnB5 — about 71% more. Tensile strength is 880 MPa (128 ksi) vs 620 MPa (89.9 ksi).

Which is cheaper, 28NiCrMoV8-5 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, 28NiCrMoV8-5 or 34MnB5?

34MnB5. Its machinability rates good (55/100) against fair (45/100) for 28NiCrMoV8-5; for welding the order is 34MnB5 first (good, 55/100) then 28NiCrMoV8-5 (poor, 30/100).

Ready to make it?

Upload a CAD file and FabDigit prices the part in 28NiCrMoV8-5 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.