Steel 20MnCrMo4-2 vs 34MnB5
Steel · grade comparison
Steel 20MnCrMo4-2 and 34MnB5 are both steel grades. Both yield at about 400 MPa — strength does not separate them. 20MnCrMo4-2 is the more ductile: elongation 20% versus 14% for 34MnB5, and 20MnCrMo4-2 is harder (195 HB vs 185 HB). 34MnB5 runs hotter in service (400°C vs 200°C continuous). On the shop floor, 34MnB5 welds better (good vs fair) and 20MnCrMo4-2 sits in a lower cost tier (budget, $) than 34MnB5 (standard, $$).
20MnCrMo4-2Choose it when the part is bent, formed or impact-loaded, or when cost is the deciding factor.
34MnB5Choose it when the part sees heat, or when it will be welded.
20MnCrMo4-2 vs 34MnB5: propertiesHow to read these bars
- One bar per material. A full bar is the highest value among all steel grades in the FabDigit library; each bar is drawn as a share of that.
- The better value (by the usual engineering direction) is in bold. Rows with no direction — density, thermal conductivity — have no bold.
- Values are typical room-temperature figures for the condition named on each card.
- Confirm against the certified mill or resin datasheet before design release.
How to read these bars
- One bar per material. A full bar is the highest value among all steel grades in the FabDigit library; each bar is drawn as a share of that.
- The better value (by the usual engineering direction) is in bold. Rows with no direction — density, thermal conductivity — have no bold.
- Values are typical room-temperature figures for the condition named on each card.
- Confirm against the certified mill or resin datasheet before design release.
Mechanical
Strength, stiffness, ductility and hardness at room temperature.
Yield Strength (0.2% offset)
Elongation at Break
Reduction in Area
Compressive Strength
Shear Strength
Fracture Toughness (K_IC)
Charpy V-Notch Impact (RT)
Hardness, Brinell
Hardness, Rockwell B
Hardness, Vickers
Same in both: Elastic (Young's) Modulus 210 GPa30.5 Msi · Shear Modulus 80 GPa11.6 Msi · Bulk Modulus 160 GPa23.2 Msi · Poisson's Ratio 0.29 · Tensile Strength (Ultimate) 620 MPa89.9 ksi · Fatigue Strength (Endurance Limit) 280 MPa40.6 ksi
Physical
Density and transition temperatures.
Liquidus Temperature
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
Thermal Expansion (CTE, 20–100 °C)
Latent Heat of Fusion
Max Service Temperature (continuous)
Same in both: Specific Heat Capacity 470 J/kg·K0.11 BTU/lb·°F · 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).
Galvanic Potential (seawater, vs SCE)
Corrosion Resistance
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Weldability
Formability (cold)
Castability
Brazeability / Solderability
Polishability
Same in both: Machinability 55 / 100 · Machinability Rating (AISI 1212 = 100 %) 60%
Sustainability
Primary-production footprint per kilogram.
Embodied Energy (primary production)
Embodied Carbon (primary production)
Embodied Water
Same in both: Typical Recycled Content 25%
Common Calculations
Ratios derived from the values above.
Modulus of Resilience
Thermal Diffusivity
Thermal Shock Resistance Index
Same in both: Specific Strength (UTS / density) 79 kN·m/kg · 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.
Manufacturing and finishing
| Capability | 20MnCrMo4-2 | 34MnB5 |
|---|---|---|
| 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.
20MnCrMo4-2 vs 34MnB5 — frequently asked
What is the difference between 20MnCrMo4-2 and 34MnB5?
Steel 20MnCrMo4-2 and 34MnB5 are both steel grades. Both yield at about 400 MPa — strength does not separate them. 20MnCrMo4-2 is the more ductile: elongation 20% versus 14% for 34MnB5, and 20MnCrMo4-2 is harder (195 HB vs 185 HB).
Which is cheaper, 20MnCrMo4-2 or 34MnB5?
20MnCrMo4-2 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, 20MnCrMo4-2 or 34MnB5?
34MnB5. Its weldability rates good (55/100) against fair (40/100) for 20MnCrMo4-2.
Ready to make it?
Upload a CAD file and FabDigit prices the part in 20MnCrMo4-2 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.