FabDigitFabDigit

Steel 34MnB5 vs X7Ni9

Steel · grade comparison

Steel 34MnB5 and X7Ni9 are both steel grades. X7Ni9 is the stronger of the two: yield strength 640 MPa (92.8 ksi) against 420 MPa (60.9 ksi) for 34MnB5, about 52% more; tensile strength follows at 730 MPa (106 ksi) vs 620 MPa (89.9 ksi). X7Ni9 is the more ductile: elongation 24% versus 14% for 34MnB5, and X7Ni9 is harder (215 HB vs 185 HB). 34MnB5 is stiffer (210 GPa vs 195 GPa) and 34MnB5 runs hotter in service (400°C vs 350°C continuous). On the shop floor, 34MnB5 machines more easily (good vs fair) and 34MnB5 sits in a lower cost tier (standard, $$) than X7Ni9 (premium, $$$).

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

X7Ni9Choose it when strength drives the design, or when the part is bent, formed or impact-loaded.

34MnB5 vs X7Ni9: properties

34MnB5X7Ni9

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

210 GPa30.5 Msi
195 GPa28.3 Msi

Shear Modulus

80 GPa11.6 Msi
76 GPa11 Msi

Tensile Strength (Ultimate)

620 MPa89.9 ksi
730 MPa106 ksi

Yield Strength (0.2% offset)

420 MPa60.9 ksi
640 MPa92.8 ksi

Elongation at Break

14%
24%

Reduction in Area

45%
65%

Shear Strength

400 MPa58 ksi
440 MPa63.8 ksi

Fatigue Strength (Endurance Limit)

280 MPa40.6 ksi
340 MPa49.3 ksi

Fracture Toughness (K_IC)

55 MPa·√m50.1 ksi·√in
180 MPa·√m164 ksi·√in

Charpy V-Notch Impact (RT)

40 J29.5 ft·lbf
200 J148 ft·lbf

Hardness, Brinell

185 HB
215 HB

Hardness, Rockwell B

89 HRB
96 HRB

Hardness, Vickers

195 HV
225 HV

Compressive Strength

—
640 MPa92.8 ksi

Hardness, Rockwell C

—
19 HRC

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

Physical

Density and transition temperatures.

Melting Point (Solidus)

1,420°C2,588 °F
1,430°C2,606 °F

Liquidus Temperature

1,495°C2,723 °F
1,500°C2,732 °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

44 W/m·K25.4 BTU/hr·ft·°F
30 W/m·K17.3 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
10.2 µm/m·K5.7 µin/in·°F

Latent Heat of Fusion

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

Max Service Temperature (continuous)

400°C752 °F
350°C662 °F

Min Service Temperature

-40°C-40 °F
-196°C-321 °F

Electrical

Conductivity and insulation.

Electrical Conductivity

8 % IACS
3.8 % IACS

Electrical Resistivity

2.2×10⁻⁷ Ω·m8.66 µΩ·in
4.5×10⁻⁷ Ω·m17.7 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Corrosion Resistance

11 / 100
16 / 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
40 / 100

Machinability Rating (AISI 1212 = 100 %)

60%
40%

Formability (cold)

60 / 100
48 / 100

Brazeability / Solderability

45 / 100
40 / 100

Polishability

55 / 100
60 / 100

Same in both: Weldability 55 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

25 MJ/kg10,748 BTU/lb
40 MJ/kg17,197 BTU/lb

Embodied Carbon (primary production)

2 kg CO₂/kg
3 kg CO₂/kg

Embodied Water

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

Same in both: Typical Recycled Content 25%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

79 kN·m/kg
93 kN·m/kg

Specific Stiffness (E / density)

26.8 MN·m/kg
24.8 MN·m/kg

Modulus of Resilience

420 kJ/m³
1,050 kJ/m³

Thermal Diffusivity

11.9 mm²/s
8.3 mm²/s

Thermal Shock Resistance Index

10
11

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 scale34MnB5X7Ni9

Manufacturing and finishing

Capability34MnB5X7Ni9
Sheet metalYes—
Default conditionCR—
Relative cost$$ Standard$$$ Premium
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 X7Ni9 — frequently asked

Is X7Ni9 stronger than 34MnB5?

Yes. X7Ni9 has a typical yield strength of 640 MPa (92.8 ksi) against 420 MPa (60.9 ksi) for 34MnB5 — about 52% more. Tensile strength is 730 MPa (106 ksi) vs 620 MPa (89.9 ksi).

Which is cheaper, 34MnB5 or X7Ni9?

34MnB5 is the lower-cost material: it sits in the standard tier ($$) while X7Ni9 is premium ($$$). Part price depends far more on geometry, tolerance and quantity than on raw stock — upload a CAD file for a live quote.

Which is easier to machine, 34MnB5 or X7Ni9?

34MnB5. Its machinability rates good (55/100) against fair (40/100) for X7Ni9.

Ready to make it?

Upload a CAD file and FabDigit prices the part in 34MnB5 and X7Ni9 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.