Stainless Steel 409 vs S40945
Stainless Steel · grade comparison
Stainless Steel 409 and S40945 are both stainless steel grades. Both yield at about 250 MPa — strength does not separate them. On the shop floor, S40945 sits in a lower cost tier (standard, $$) than 409 (premium, $$$).
S40945Choose it when cost is the deciding factor.
409 vs S40945: propertiesHow to read these bars
- One bar per material. A full bar is the highest value among all stainless 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 stainless 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
Poisson's Ratio
Elongation at Break
Shear Strength
Charpy V-Notch Impact (RT)
Hardness, Brinell
Hardness, Rockwell B
Same in both: Elastic (Young's) Modulus 200 GPa29 Msi · Bulk Modulus 160 GPa23.2 Msi · Tensile Strength (Ultimate) 450 MPa65.3 ksi · Yield Strength (0.2% offset) 250 MPa36.3 ksi · Reduction in Area 65% · Compressive Strength 250 MPa36.3 ksi · Fatigue Strength (Endurance Limit) 230 MPa33.4 ksi · Hardness, Vickers 155 HV
Physical
Density and transition temperatures.
Melting Point (Solidus)
Liquidus Temperature
Same in both: Density 7.7 g/cm³0.28 lb/in³
Thermal
How each material carries heat and how hot it can run.
Thermal Conductivity
Thermal Expansion (CTE, 20–100 °C)
Latent Heat of Fusion
Min Service Temperature
Same in both: Specific Heat Capacity 460 J/kg·K0.11 BTU/lb·°F · Max Service Temperature (continuous) 675°C1,247 °F
Electrical
Conductivity and insulation.
Same in both: Electrical Conductivity 2.9 % IACS · Electrical Resistivity 6×10⁻⁷ Ω·m23.6 µΩ·in
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Corrosion Resistance
Same in both: Galvanic Potential (seawater, vs SCE) -0.35 V
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Weldability
Formability (cold)
Brazeability / Solderability
Same in both: Machinability Rating (AISI 1212 = 100 %) 65% · Polishability 55 / 100
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.
Thermal Diffusivity
Same in both: Specific Strength (UTS / density) 58 kN·m/kg · Specific Stiffness (E / density) 26 MN·m/kg · Modulus of Resilience 156 kJ/m³ · Thermal Shock Resistance Index 5
Strength versus weight
Yield strength against density for every stainless steel grade in the FabDigit library; the compared grades are highlighted. Up and left is stronger for its weight.
Manufacturing and finishing
| Capability | 409 | S40945 |
|---|---|---|
| CNC machining | Yes | — |
| Sheet metal | Yes | — |
| Default condition | Annealed | — |
| 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 | — |
| Electropolishing | Yes | — |
| HVOF Coating | Yes | — |
| MoS2 | Yes | — |
| Multilayer CVD | Yes | — |
| Nickel Plating | Yes | — |
| PTFE Coating | Yes | — |
| Painting | Yes | — |
| Passivation (Stainless Steel) | Yes | — |
They share 7 finishes: Electroless Nickel (EN), Epoxy Coating, Gold Plating, Hard Chrome Plating, Pickling, Plasma Spray, Silver Plating.
409 vs S40945 — frequently asked
What is the difference between 409 and S40945?
Stainless Steel 409 and S40945 are both stainless steel grades. Both yield at about 250 MPa — strength does not separate them. On the shop floor, S40945 sits in a lower cost tier (standard, $$) than 409 (premium, $$$).
Which is cheaper, 409 or S40945?
S40945 is the lower-cost material: it sits in the standard tier ($$) while 409 is premium ($$$). 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, 409 or S40945?
S40945, by a small margin. Both rate good for machinability — 60/100 against 55/100 for 409; for welding the order is S40945 first (excellent, 88/100) then 409 (very good, 80/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in 409 and S40945 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.