Steel 31CrMoV9 vs 55Cr3
Steel · grade comparison
Steel 31CrMoV9 and 55Cr3 are both steel grades. 31CrMoV9 is the stronger of the two: yield strength 880 MPa (128 ksi) against 480 MPa (69.6 ksi) for 55Cr3, about 83% more; tensile strength follows at 1,100 MPa (160 ksi) vs 800 MPa (116 ksi). In exchange, 55Cr3 is the more ductile: elongation 16% versus 12% for 31CrMoV9, and 31CrMoV9 is harder (330 HB vs 225 HB). 31CrMoV9 runs hotter in service (450°C vs 400°C continuous) and 55Cr3 conducts heat better (44 W/m·K vs 36 W/m·K). On the shop floor, 55Cr3 machines more easily (50 vs 40 out of 100).
31CrMoV9Choose it when strength drives the design, or when the part sees heat.
55Cr3Choose it when the part is bent, formed or impact-loaded, or when the part is machined in volume.
31CrMoV9 vs 55Cr3: 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.
Elastic (Young's) Modulus
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: Bulk Modulus 160 GPa23.2 Msi · Poisson's Ratio 0.29
Physical
Density and transition temperatures.
Same in both: Density 7.85 g/cm³0.28 lb/in³ · Melting Point (Solidus) 1,420°C2,588 °F · Liquidus Temperature 1,490°C2,714 °F
Thermal
How each material carries heat and how hot it can run.
Thermal Conductivity
Thermal Expansion (CTE, 20–100 °C)
Max Service Temperature (continuous)
Same in both: Specific Heat Capacity 465 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.
Electrical Conductivity
Same in both: Electrical Resistivity 2.2×10⁻⁷ Ω·m8.66 µΩ·in
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Corrosion Resistance
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Machinability Rating (AISI 1212 = 100 %)
Weldability
Formability (cold)
Castability
Brazeability / Solderability
Polishability
Sustainability
Primary-production footprint per kilogram.
Embodied Energy (primary production)
Embodied Carbon (primary production)
Embodied Water
Typical Recycled Content
Common Calculations
Ratios derived from the values above.
Specific Strength (UTS / density)
Specific Stiffness (E / density)
Modulus of Resilience
Thermal Diffusivity
Thermal Shock Resistance Index
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 | 31CrMoV9 | 55Cr3 |
|---|---|---|
| Default condition | Q&T | Annealed |
| Relative cost | $$ Standard | $$ Standard |
| Min. machined wall | 0.8 mm | 0.8 mm |
| Best machined surface | Ra 1.6 µm | Ra 1.6 µm |
Both are offered for CNC machining and Sheet metal. Both take the same 38 finishes: AlCrN, AlTiN, Black Oxide, CVD Al2O3, CVD TiCN, CVD TiN, Cerakote, Chrome Plating, Copper Plating, CrN, DLC, E-Coating and 26 more.
31CrMoV9 vs 55Cr3 — frequently asked
Is 31CrMoV9 stronger than 55Cr3?
Yes. 31CrMoV9 has a typical yield strength of 880 MPa (128 ksi) against 480 MPa (69.6 ksi) for 55Cr3 — about 83% more. Tensile strength is 1,100 MPa (160 ksi) vs 800 MPa (116 ksi).
Which is cheaper, 31CrMoV9 or 55Cr3?
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, 31CrMoV9 or 55Cr3?
55Cr3, by a small margin. Both rate fair for machinability — 50/100 against 40/100 for 31CrMoV9; for welding the order is 55Cr3 first (poor, 25/100) then 31CrMoV9 (poor, 20/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in 31CrMoV9 and 55Cr3 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.