Steel 21CrMoV5-7 vs 34MnB5
Steel · grade comparison
Steel 21CrMoV5-7 and 34MnB5 are both steel grades. 21CrMoV5-7 is the stronger of the two: yield strength 700 MPa (102 ksi) against 420 MPa (60.9 ksi) for 34MnB5, about 67% more; tensile strength follows at 830 MPa (120 ksi) vs 620 MPa (89.9 ksi). 21CrMoV5-7 is the more ductile: elongation 18% versus 14% for 34MnB5, and 21CrMoV5-7 is harder (250 HB vs 185 HB). 21CrMoV5-7 runs hotter in service (540°C vs 400°C continuous) and 34MnB5 conducts heat better (44 W/m·K vs 39 W/m·K). On the shop floor, 34MnB5 machines more easily (good vs fair) and 34MnB5 welds better (good vs fair).
21CrMoV5-7Choose it when strength drives the design, or when the part is bent, formed or impact-loaded.
34MnB5Choose it when the part is machined in volume, or when it will be welded.
21CrMoV5-7 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.
Shear Modulus
Tensile Strength (Ultimate)
Yield Strength (0.2% offset)
Elongation at Break
Reduction in Area
Compressive Strength
Shear Strength
Fatigue Strength (Endurance Limit)
Fracture Toughness (K_IC)
Charpy V-Notch Impact (RT)
Hardness, Brinell
Hardness, Rockwell C
Hardness, Vickers
Hardness, Rockwell B
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.
Melting Point (Solidus)
Liquidus Temperature
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
Specific Heat Capacity
Thermal Expansion (CTE, 20–100 °C)
Max Service Temperature (continuous)
Min Service Temperature
Same in both: Latent Heat of Fusion 250 J/g107 BTU/lb
Electrical
Conductivity and insulation.
Electrical Conductivity
Electrical Resistivity
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Corrosion Resistance
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
Machinability Rating (AISI 1212 = 100 %)
Weldability
Formability (cold)
Castability
Polishability
Same in both: Brazeability / Solderability 45 / 100
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.
Specific Strength (UTS / density)
Modulus of Resilience
Thermal Diffusivity
Thermal Shock Resistance Index
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.
Manufacturing and finishing
| Capability | 21CrMoV5-7 | 34MnB5 |
|---|---|---|
| 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.
21CrMoV5-7 vs 34MnB5 — frequently asked
Is 21CrMoV5-7 stronger than 34MnB5?
Yes. 21CrMoV5-7 has a typical yield strength of 700 MPa (102 ksi) against 420 MPa (60.9 ksi) for 34MnB5 — about 67% more. Tensile strength is 830 MPa (120 ksi) vs 620 MPa (89.9 ksi).
Which is cheaper, 21CrMoV5-7 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, 21CrMoV5-7 or 34MnB5?
34MnB5. Its machinability rates good (55/100) against fair (42/100) for 21CrMoV5-7; for welding the order is 34MnB5 first (good, 55/100) then 21CrMoV5-7 (fair, 35/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in 21CrMoV5-7 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.