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Steel 34MnB5 vs E730K2

Steel · grade comparison

Steel 34MnB5 and E730K2 are both steel grades. E730K2 is the stronger of the two: yield strength 780 MPa (113 ksi) against 420 MPa (60.9 ksi) for 34MnB5, about 86% more; tensile strength follows at 870 MPa (126 ksi) vs 620 MPa (89.9 ksi). E730K2 is harder — 270 HB against 185 HB for 34MnB5 — which matters for wear surfaces and threads. 34MnB5 runs hotter in service (400°C vs 300°C continuous). On the shop floor, 34MnB5 machines more easily (good vs fair) and 34MnB5 forms better (good vs fair).

34MnB5Choose it when the part sees heat, or when the part is machined in volume.

E730K2Choose it when strength drives the design, or when surface hardness matters.

34MnB5 vs E730K2: properties

34MnB5E730K2

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Shear Modulus

80 GPa11.6 Msi
81 GPa11.7 Msi

Poisson's Ratio

0.29
0.3

Tensile Strength (Ultimate)

620 MPa89.9 ksi
870 MPa126 ksi

Yield Strength (0.2% offset)

420 MPa60.9 ksi
780 MPa113 ksi

Reduction in Area

45%
50%

Shear Strength

400 MPa58 ksi
520 MPa75.4 ksi

Fatigue Strength (Endurance Limit)

280 MPa40.6 ksi
400 MPa58 ksi

Fracture Toughness (K_IC)

55 MPa·√m50.1 ksi·√in
95 MPa·√m86.5 ksi·√in

Charpy V-Notch Impact (RT)

40 J29.5 ft·lbf
55 J40.6 ft·lbf

Hardness, Brinell

185 HB
270 HB

Hardness, Rockwell B

89 HRB
—

Hardness, Vickers

195 HV
285 HV

Compressive Strength

—
780 MPa113 ksi

Hardness, Rockwell C

—
27 HRC

Same in both: Elastic (Young's) Modulus 210 GPa30.5 Msi · Bulk Modulus 160 GPa23.2 Msi · Elongation at Break 14%

Physical

Density and transition temperatures.

Liquidus Temperature

1,495°C2,723 °F
1,500°C2,732 °F

Same in both: Density 7.85 g/cm³0.28 lb/in³ · 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
40 W/m·K23.1 BTU/hr·ft·°F

Specific Heat Capacity

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

Thermal Expansion (CTE, 20–100 °C)

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

Latent Heat of Fusion

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

Max Service Temperature (continuous)

400°C752 °F
300°C572 °F

Same in both: Min Service Temperature -40°C-40 °F

Electrical

Conductivity and insulation.

Electrical Conductivity

8 % IACS
7.5 % IACS

Electrical Resistivity

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

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Galvanic Potential (seawater, vs SCE)

-0.6 V
—

Corrosion Resistance

11 / 100
12 / 100

Manufacturability

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

Machinability

55 / 100
45 / 100

Machinability Rating (AISI 1212 = 100 %)

60%
50%

Formability (cold)

60 / 100
35 / 100

Brazeability / Solderability

45 / 100
40 / 100

Same in both: Weldability 55 / 100 · Polishability 55 / 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
2.2 kg CO₂/kg

Embodied Water

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

Typical Recycled Content

25%
30%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

79 kN·m/kg
111 kN·m/kg

Modulus of Resilience

420 kJ/m³
1,449 kJ/m³

Thermal Diffusivity

11.9 mm²/s
11.1 mm²/s

Thermal Shock Resistance Index

10
14

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 scale34MnB5E730K2

Manufacturing and finishing

Capability34MnB5E730K2
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 E730K2 — frequently asked

Is E730K2 stronger than 34MnB5?

Yes. E730K2 has a typical yield strength of 780 MPa (113 ksi) against 420 MPa (60.9 ksi) for 34MnB5 — about 86% more. Tensile strength is 870 MPa (126 ksi) vs 620 MPa (89.9 ksi).

Which is cheaper, 34MnB5 or E730K2?

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 E730K2?

34MnB5. Its machinability rates good (55/100) against fair (45/100) for E730K2.

Ready to make it?

Upload a CAD file and FabDigit prices the part in 34MnB5 and E730K2 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.