Steel 30CrMnSiNi2A vs 40CrNiMoA
Steel · grade comparison
Steel 30CrMnSiNi2A and 40CrNiMoA are both steel grades. 30CrMnSiNi2A is the stronger of the two: yield strength 1,450 MPa (210 ksi) against 950 MPa (138 ksi) for 40CrNiMoA, about 53% more; tensile strength follows at 1,700 MPa (247 ksi) vs 1,080 MPa (157 ksi). In exchange, 40CrNiMoA is the more ductile: elongation 16% versus 12% for 30CrMnSiNi2A, and 30CrMnSiNi2A is harder (48 HRC vs 34 HRC). 40CrNiMoA runs hotter in service (400°C vs 250°C continuous) and 40CrNiMoA conducts heat better (44 W/m·K vs 31 W/m·K). On the shop floor, 40CrNiMoA machines more easily (fair vs poor), 40CrNiMoA welds better (30 vs 20 out of 100), and 40CrNiMoA sits in a lower cost tier (standard, $$) than 30CrMnSiNi2A (premium, $$$).
30CrMnSiNi2AChoose it when strength drives the design.
40CrNiMoAChoose it when the part is bent, formed or impact-loaded, or when the part sees heat.
30CrMnSiNi2A vs 40CrNiMoA: 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
Poisson's Ratio
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, Rockwell C
Hardness, Vickers
Hardness, Brinell
Same in both: Bulk Modulus 160 GPa23.2 Msi
Physical
Density and transition temperatures.
Density
Liquidus Temperature
Same in both: Melting Point (Solidus) 1,420°C2,588 °F
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)
Same in both: Latent Heat of Fusion 250 J/g107 BTU/lb · Min Service Temperature -60°C-76 °F
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)
Brazeability / Solderability
Polishability
Castability
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 | 30CrMnSiNi2A | 40CrNiMoA |
|---|---|---|
| CNC machining | — | Yes |
| Sheet metal | — | Yes |
| Default condition | — | Q&T |
| Relative cost | $$$ Premium | $$ Standard |
| Min. machined wall | — | 0.8 mm |
| Best machined surface | — | Ra 1.6 µm |
| AlCrN | — | Yes |
| AlTiN | — | Yes |
| Black Oxide | — | Yes |
| CVD Al2O3 | — | Yes |
| CVD TiCN | — | Yes |
| CVD TiN | — | Yes |
| Cerakote | — | Yes |
| Chrome Plating | — | Yes |
| CrN | — | Yes |
| DLC | — | Yes |
| E-Coating | — | Yes |
| HVOF Coating | — | Yes |
| Hot-Dip Galvanizing | — | Yes |
| MoS2 | — | Yes |
| Multilayer CVD | — | Yes |
| Nickel Plating | — | Yes |
| PTFE Coating | — | Yes |
| Painting | — | 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.
30CrMnSiNi2A vs 40CrNiMoA — frequently asked
Is 30CrMnSiNi2A stronger than 40CrNiMoA?
Yes. 30CrMnSiNi2A has a typical yield strength of 1,450 MPa (210 ksi) against 950 MPa (138 ksi) for 40CrNiMoA — about 53% more. Tensile strength is 1,700 MPa (247 ksi) vs 1,080 MPa (157 ksi).
Which is cheaper, 30CrMnSiNi2A or 40CrNiMoA?
40CrNiMoA is the lower-cost material: it sits in the standard tier ($$) while 30CrMnSiNi2A is premium ($$$). Part price depends far more on geometry, tolerance and quantity than on raw stock — upload a CAD file for a live quote.
Which is easier to machine, 30CrMnSiNi2A or 40CrNiMoA?
40CrNiMoA. Its machinability rates fair (42/100) against poor (22/100) for 30CrMnSiNi2A; for welding the order is 40CrNiMoA first (poor, 30/100) then 30CrMnSiNi2A (poor, 20/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in 30CrMnSiNi2A and 40CrNiMoA 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.