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Steel 20Cr3 vs 34MnB5

Steel · grade comparison

Steel 20Cr3 and 34MnB5 are both steel grades. 34MnB5 is the stronger of the two: yield strength 420 MPa (60.9 ksi) against 320 MPa (46.4 ksi) for 20Cr3, about 31% more; tensile strength follows at 620 MPa (89.9 ksi) vs 550 MPa (79.8 ksi). In exchange, 20Cr3 is the more ductile: elongation 22% versus 14% for 34MnB5, and 34MnB5 is harder (185 HB vs 170 HB). 34MnB5 runs hotter in service (400°C vs 300°C continuous). On the shop floor, 34MnB5 welds better (good vs fair) and 20Cr3 sits in a lower cost tier (budget, $) than 34MnB5 (standard, $$).

20Cr3Choose it when the part is bent, formed or impact-loaded, or when cost is the deciding factor.

34MnB5Choose it when strength drives the design, or when the part sees heat.

20Cr3 vs 34MnB5: properties

20Cr334MnB5

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Shear Modulus

81 GPa11.7 Msi
80 GPa11.6 Msi

Tensile Strength (Ultimate)

550 MPa79.8 ksi
620 MPa89.9 ksi

Yield Strength (0.2% offset)

320 MPa46.4 ksi
420 MPa60.9 ksi

Elongation at Break

22%
14%

Reduction in Area

55%
45%

Compressive Strength

330 MPa47.9 ksi
—

Shear Strength

340 MPa49.3 ksi
400 MPa58 ksi

Fatigue Strength (Endurance Limit)

250 MPa36.3 ksi
280 MPa40.6 ksi

Fracture Toughness (K_IC)

75 MPa·√m68.3 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

170 HB
185 HB

Hardness, Rockwell B

86 HRB
89 HRB

Hardness, Vickers

—
195 HV

Same in both: Elastic (Young's) Modulus 210 GPa30.5 Msi · Bulk Modulus 160 GPa23.2 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 Expansion (CTE, 20–100 °C)

11.9 µm/m·K6.6 µin/in·°F
12.5 µm/m·K6.9 µin/in·°F

Max Service Temperature (continuous)

300°C572 °F
400°C752 °F

Same in both: Thermal Conductivity 44 W/m·K25.4 BTU/hr·ft·°F · 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.

Same in both: Electrical Conductivity 8 % IACS · Electrical Resistivity 2.2×10⁻⁷ Ω·m8.66 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Corrosion Resistance

12 / 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.

Weldability

45 / 100
55 / 100

Brazeability / Solderability

60 / 100
45 / 100

Polishability

70 / 100
55 / 100

Same in both: Machinability 55 / 100 · Machinability Rating (AISI 1212 = 100 %) 60% · Formability (cold) 60 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

24 MJ/kg10,318 BTU/lb
25 MJ/kg10,748 BTU/lb

Embodied Carbon (primary production)

1.9 kg CO₂/kg
2 kg CO₂/kg

Embodied Water

45 L/kg5.4 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)

70 kN·m/kg
79 kN·m/kg

Modulus of Resilience

244 kJ/m³
420 kJ/m³

Thermal Diffusivity

12 mm²/s
11.9 mm²/s

Same in both: Specific Stiffness (E / density) 26.8 MN·m/kg · Thermal Shock Resistance Index 10

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 scale34MnB520Cr3

Manufacturing and finishing

Capability20Cr334MnB5
Sheet metal—Yes
Default condition—CR
Relative cost$ Budget$$ 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.

20Cr3 vs 34MnB5 — frequently asked

Is 34MnB5 stronger than 20Cr3?

Yes. 34MnB5 has a typical yield strength of 420 MPa (60.9 ksi) against 320 MPa (46.4 ksi) for 20Cr3 — about 31% more. Tensile strength is 620 MPa (89.9 ksi) vs 550 MPa (79.8 ksi).

Which is cheaper, 20Cr3 or 34MnB5?

20Cr3 is the lower-cost material: it sits in the budget tier ($) while 34MnB5 is standard ($$). Part price depends far more on geometry, tolerance and quantity than on raw stock — upload a CAD file for a live quote.

Which welds better, 20Cr3 or 34MnB5?

34MnB5. Its weldability rates good (55/100) against fair (45/100) for 20Cr3.

Ready to make it?

Upload a CAD file and FabDigit prices the part in 20Cr3 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.