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Steel 20Cr2Ni4A vs 34MnB5

Steel · grade comparison

Steel 20Cr2Ni4A and 34MnB5 are both steel grades. 20Cr2Ni4A is the stronger of the two: yield strength 1,120 MPa (162 ksi) against 420 MPa (60.9 ksi) for 34MnB5, about 167% more; tensile strength follows at 1,250 MPa (181 ksi) vs 620 MPa (89.9 ksi). In exchange, 34MnB5 is the more ductile: elongation 14% versus 12% for 20Cr2Ni4A, and 20Cr2Ni4A is harder (375 HB vs 185 HB). 34MnB5 runs hotter in service (400°C vs 200°C continuous) and 34MnB5 conducts heat better (44 W/m·K vs 32 W/m·K). On the shop floor, 34MnB5 machines more easily (good vs poor) and 34MnB5 welds better (good vs poor).

20Cr2Ni4AChoose it when strength drives the design.

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

20Cr2Ni4A vs 34MnB5: properties

20Cr2Ni4A34MnB5

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

208 GPa30.2 Msi
210 GPa30.5 Msi

Bulk Modulus

165 GPa23.9 Msi
160 GPa23.2 Msi

Poisson's Ratio

0.3
0.29

Tensile Strength (Ultimate)

1,250 MPa181 ksi
620 MPa89.9 ksi

Yield Strength (0.2% offset)

1,120 MPa162 ksi
420 MPa60.9 ksi

Elongation at Break

12%
14%

Reduction in Area

52%
45%

Compressive Strength

1,120 MPa162 ksi
—

Shear Strength

750 MPa109 ksi
400 MPa58 ksi

Fatigue Strength (Endurance Limit)

560 MPa81.2 ksi
280 MPa40.6 ksi

Fracture Toughness (K_IC)

80 MPa·√m72.8 ksi·√in
55 MPa·√m50.1 ksi·√in

Charpy V-Notch Impact (RT)

65 J47.9 ft·lbf
40 J29.5 ft·lbf

Hardness, Brinell

375 HB
185 HB

Hardness, Rockwell C

40 HRC
—

Hardness, Vickers

395 HV
195 HV

Hardness, Rockwell B

—
89 HRB

Same in both: Shear Modulus 80 GPa11.6 Msi

Physical

Density and transition temperatures.

Liquidus Temperature

1,490°C2,714 °F
1,495°C2,723 °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

32 W/m·K18.5 BTU/hr·ft·°F
44 W/m·K25.4 BTU/hr·ft·°F

Thermal Expansion (CTE, 20–100 °C)

11.6 µm/m·K6.4 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

Max Service Temperature (continuous)

200°C392 °F
400°C752 °F

Min Service Temperature

-70°C-94 °F
-40°C-40 °F

Same in both: Specific Heat Capacity 470 J/kg·K0.11 BTU/lb·°F

Electrical

Conductivity and insulation.

Electrical Conductivity

5.7 % IACS
8 % IACS

Electrical Resistivity

3×10⁻⁷ Ω·m11.8 µΩ·in
2.2×10⁻⁷ Ω·m8.66 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Corrosion Resistance

15 / 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

25 / 100
55 / 100

Machinability Rating (AISI 1212 = 100 %)

30%
60%

Weldability

20 / 100
55 / 100

Formability (cold)

25 / 100
60 / 100

Polishability

75 / 100
55 / 100

Same in both: Brazeability / Solderability 45 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

36 MJ/kg15,477 BTU/lb
25 MJ/kg10,748 BTU/lb

Embodied Carbon (primary production)

2.8 kg CO₂/kg
2 kg CO₂/kg

Embodied Water

65 L/kg7.8 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)

159 kN·m/kg
79 kN·m/kg

Specific Stiffness (E / density)

26.5 MN·m/kg
26.8 MN·m/kg

Modulus of Resilience

3,015 kJ/m³
420 kJ/m³

Thermal Diffusivity

8.7 mm²/s
11.9 mm²/s

Thermal Shock Resistance Index

17
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 scale34MnB520Cr2Ni4A

Manufacturing and finishing

Capability20Cr2Ni4A34MnB5
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.

20Cr2Ni4A vs 34MnB5 — frequently asked

Is 20Cr2Ni4A stronger than 34MnB5?

Yes. 20Cr2Ni4A has a typical yield strength of 1,120 MPa (162 ksi) against 420 MPa (60.9 ksi) for 34MnB5 — about 167% more. Tensile strength is 1,250 MPa (181 ksi) vs 620 MPa (89.9 ksi).

Which is cheaper, 20Cr2Ni4A 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, 20Cr2Ni4A or 34MnB5?

34MnB5. Its machinability rates good (55/100) against poor (25/100) for 20Cr2Ni4A; for welding the order is 34MnB5 first (good, 55/100) then 20Cr2Ni4A (poor, 20/100).

Ready to make it?

Upload a CAD file and FabDigit prices the part in 20Cr2Ni4A 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.