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Steel 34MnB5 vs 45SiCrV6-2

Steel · grade comparison

Steel 34MnB5 and 45SiCrV6-2 are both steel grades. 45SiCrV6-2 is the stronger of the two: yield strength 1,500 MPa (218 ksi) against 420 MPa (60.9 ksi) for 34MnB5, about 3.6 times as much; tensile strength follows at 1,700 MPa (247 ksi) vs 620 MPa (89.9 ksi). In exchange, 34MnB5 is the more ductile: elongation 14% versus 7% for 45SiCrV6-2, and 45SiCrV6-2 is harder (490 HB vs 185 HB). 34MnB5 runs hotter in service (400°C vs 250°C continuous) and 34MnB5 conducts electricity better (8 % IACS vs 7 % IACS). On the shop floor, 34MnB5 machines more easily (good vs poor) and 34MnB5 welds better (good vs poor).

34MnB5Choose it when the part is bent, formed or impact-loaded, or when the part sees heat.

45SiCrV6-2Choose it when strength drives the design.

34MnB5 vs 45SiCrV6-2: properties

34MnB545SiCrV6-2

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

210 GPa30.5 Msi
206 GPa29.9 Msi

Shear Modulus

80 GPa11.6 Msi
79.5 GPa11.5 Msi

Tensile Strength (Ultimate)

620 MPa89.9 ksi
1,700 MPa247 ksi

Yield Strength (0.2% offset)

420 MPa60.9 ksi
1,500 MPa218 ksi

Elongation at Break

14%
7%

Reduction in Area

45%
30%

Shear Strength

400 MPa58 ksi
1,020 MPa148 ksi

Fatigue Strength (Endurance Limit)

280 MPa40.6 ksi
700 MPa102 ksi

Fracture Toughness (K_IC)

55 MPa·√m50.1 ksi·√in
50 MPa·√m45.5 ksi·√in

Charpy V-Notch Impact (RT)

40 J29.5 ft·lbf
20 J14.8 ft·lbf

Hardness, Brinell

185 HB
490 HB

Hardness, Rockwell B

89 HRB
—

Hardness, Vickers

195 HV
520 HV

Compressive Strength

—
1,550 MPa225 ksi

Hardness, Rockwell C

—
50 HRC

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

Physical

Density and transition temperatures.

Density

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

Liquidus Temperature

1,495°C2,723 °F
1,490°C2,714 °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

44 W/m·K25.4 BTU/hr·ft·°F
42 W/m·K24.3 BTU/hr·ft·°F

Thermal Expansion (CTE, 20–100 °C)

12.5 µm/m·K6.9 µin/in·°F
11.5 µm/m·K6.4 µin/in·°F

Max Service Temperature (continuous)

400°C752 °F
250°C482 °F

Same in both: Specific Heat Capacity 470 J/kg·K0.11 BTU/lb·°F · Latent Heat of Fusion 250 J/g107 BTU/lb · Min Service Temperature -40°C-40 °F

Electrical

Conductivity and insulation.

Electrical Conductivity

8 % IACS
7 % IACS

Electrical Resistivity

2.2×10⁻⁷ Ω·m8.66 µΩ·in
2.5×10⁻⁷ Ω·m9.84 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Corrosion Resistance

11 / 100
12 / 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

55 / 100
28 / 100

Machinability Rating (AISI 1212 = 100 %)

60%
25%

Weldability

55 / 100
15 / 100

Formability (cold)

60 / 100
8 / 100

Brazeability / Solderability

45 / 100
35 / 100

Polishability

55 / 100
60 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

25 MJ/kg10,748 BTU/lb
30 MJ/kg12,898 BTU/lb

Embodied Carbon (primary production)

2 kg CO₂/kg
2.1 kg CO₂/kg

Embodied Water

40 L/kg4.8 gal/lb
50 L/kg6 gal/lb

Typical Recycled Content

25%
30%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

79 kN·m/kg
218 kN·m/kg

Specific Stiffness (E / density)

26.8 MN·m/kg
26.4 MN·m/kg

Modulus of Resilience

420 kJ/m³
5,461 kJ/m³

Thermal Diffusivity

11.9 mm²/s
11.5 mm²/s

Thermal Shock Resistance Index

10
30

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 scale34MnB545SiCrV6-2

Manufacturing and finishing

Capability34MnB545SiCrV6-2
Sheet metalYes—
Default conditionCR—
Relative cost$$ Standard$$ Standard
Min. machined wall——
Best machined surface——
Black OxideYes—
CerakoteYes—
Chrome PlatingYes—
E-CoatingYes—
Hot-Dip GalvanizingYes—
Nickel PlatingYes—
PTFE CoatingYes—
PaintingYes—
Powder CoatingYes—
Tin PlatingYes—
Zinc PlatingYes—
Zinc-Flake (Dip-Spin) CoatingYes—
Zinc-Nickel PlatingYes—

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

34MnB5 vs 45SiCrV6-2 — frequently asked

Is 45SiCrV6-2 stronger than 34MnB5?

Yes. 45SiCrV6-2 has a typical yield strength of 1,500 MPa (218 ksi) against 420 MPa (60.9 ksi) for 34MnB5 — about 3.6 times as much. Tensile strength is 1,700 MPa (247 ksi) vs 620 MPa (89.9 ksi).

Which is cheaper, 34MnB5 or 45SiCrV6-2?

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, 34MnB5 or 45SiCrV6-2?

34MnB5. Its machinability rates good (55/100) against poor (28/100) for 45SiCrV6-2; for welding the order is 34MnB5 first (good, 55/100) then 45SiCrV6-2 (poor, 15/100).

Ready to make it?

Upload a CAD file and FabDigit prices the part in 34MnB5 and 45SiCrV6-2 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.