Stainless Steel 409 vs 439
Stainless Steel · grade comparison
Stainless Steel 409 and 439 are both stainless steel grades. 439 is the stronger of the two: yield strength 310 MPa (45 ksi) against 250 MPa (36.3 ksi) for 409, about 24% more; tensile strength follows at 485 MPa (70.3 ksi) vs 450 MPa (65.3 ksi). 439 runs hotter in service (815°C vs 675°C continuous).
439Choose it when strength drives the design, or when the part sees heat.
409 vs 439: 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.
Poisson's Ratio
Tensile Strength (Ultimate)
Yield Strength (0.2% offset)
Reduction in Area
Compressive Strength
Shear Strength
Fatigue Strength (Endurance Limit)
Hardness, Vickers
Fracture Toughness (K_IC)
Same in both: Elastic (Young's) Modulus 200 GPa29 Msi · Shear Modulus 77 GPa11.2 Msi · Bulk Modulus 160 GPa23.2 Msi · Elongation at Break 30% · Charpy V-Notch Impact (RT) 40 J29.5 ft·lbf · Hardness, Brinell 150 HB · Hardness, Rockwell B 80 HRB
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)
Max Service Temperature (continuous)
Min Service Temperature
Same in both: Specific Heat Capacity 460 J/kg·K0.11 BTU/lb·°F · Latent Heat of Fusion 260 J/g112 BTU/lb
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).
Galvanic Potential (seawater, vs SCE)
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)
Brazeability / Solderability
Polishability
Sustainability
Primary-production footprint per kilogram.
Embodied Energy (primary production)
Embodied Carbon (primary production)
Same in both: Embodied Water 90 L/kg10.8 gal/lb · Typical Recycled Content 65%
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 MN·m/kg
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 | 439 |
|---|---|---|
| Default condition | Annealed | Annealed |
| Relative cost | $$$ Premium | $$$ Premium |
| 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 32 finishes: AlCrN, AlTiN, Black Oxide, CVD Al2O3, CVD TiCN, CVD TiN, Cerakote, Chrome Plating, CrN, DLC, Electroless Nickel (EN), Electropolishing and 20 more.
409 vs 439 — frequently asked
Is 439 stronger than 409?
Yes. 439 has a typical yield strength of 310 MPa (45 ksi) against 250 MPa (36.3 ksi) for 409 — about 24% more. Tensile strength is 485 MPa (70.3 ksi) vs 450 MPa (65.3 ksi).
Which is cheaper, 409 or 439?
Both sit in the same relative cost tier ($$$, premium); the part price will be decided by machining time, tolerance and quantity rather than by the material.
Which is easier to machine, 409 or 439?
409. Its machinability rates good (55/100) against fair (50/100) for 439.
Ready to make it?
Upload a CAD file and FabDigit prices the part in 409 and 439 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.