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Stainless Steel 409 vs 446

Stainless Steel · grade comparison

Stainless Steel 409 and 446 are both stainless steel grades, both heat resistant ss. 446 is the stronger of the two: yield strength 350 MPa (50.8 ksi) against 250 MPa (36.3 ksi) for 409, about 40% more; tensile strength follows at 550 MPa (79.8 ksi) vs 450 MPa (65.3 ksi). In exchange, 409 is the more ductile: elongation 30% versus 22% for 446, and 446 is harder (180 HB vs 150 HB). 446 runs hotter in service (1,095°C vs 675°C continuous) and 409 conducts heat better (24.9 W/m·K vs 20.9 W/m·K). On the shop floor, 409 machines more easily (good vs fair) and 409 welds better (very good vs poor).

409Choose it when the part is bent, formed or impact-loaded, or when the part is machined in volume.

446Choose it when strength drives the design, or when the part sees heat.

409 vs 446: properties

409446

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Shear Modulus

77 GPa11.2 Msi
78 GPa11.3 Msi

Bulk Modulus

160 GPa23.2 Msi
152 GPa22 Msi

Poisson's Ratio

0.3
0.28

Tensile Strength (Ultimate)

450 MPa65.3 ksi
550 MPa79.8 ksi

Yield Strength (0.2% offset)

250 MPa36.3 ksi
350 MPa50.8 ksi

Elongation at Break

30%
22%

Reduction in Area

65%
45%

Compressive Strength

250 MPa36.3 ksi
—

Shear Strength

280 MPa40.6 ksi
350 MPa50.8 ksi

Fatigue Strength (Endurance Limit)

230 MPa33.4 ksi
260 MPa37.7 ksi

Charpy V-Notch Impact (RT)

40 J29.5 ft·lbf
15 J11.1 ft·lbf

Hardness, Brinell

150 HB
180 HB

Hardness, Rockwell B

80 HRB
86 HRB

Hardness, Vickers

155 HV
190 HV

Same in both: Elastic (Young's) Modulus 200 GPa29 Msi

Physical

Density and transition temperatures.

Density

7.7 g/cm³0.28 lb/in³
7.5 g/cm³0.27 lb/in³

Melting Point (Solidus)

1,482°C2,700 °F
1,425°C2,597 °F

Liquidus Temperature

1,532°C2,790 °F
1,510°C2,750 °F

Thermal

How each material carries heat and how hot it can run.

Thermal Conductivity

24.9 W/m·K14.4 BTU/hr·ft·°F
20.9 W/m·K12.1 BTU/hr·ft·°F

Specific Heat Capacity

460 J/kg·K0.11 BTU/lb·°F
500 J/kg·K0.12 BTU/lb·°F

Thermal Expansion (CTE, 20–100 °C)

11.7 µm/m·K6.5 µin/in·°F
10.4 µm/m·K5.8 µin/in·°F

Latent Heat of Fusion

260 J/g112 BTU/lb
270 J/g116 BTU/lb

Max Service Temperature (continuous)

675°C1,247 °F
1,095°C2,003 °F

Same in both: Min Service Temperature -20°C-4 °F

Electrical

Conductivity and insulation.

Electrical Conductivity

2.9 % IACS
2.6 % IACS

Electrical Resistivity

6×10⁻⁷ Ω·m23.6 µΩ·in
6.7×10⁻⁷ Ω·m26.4 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Galvanic Potential (seawater, vs SCE)

-0.35 V
-0.1 V

Corrosion Resistance

40 / 100
62 / 100

Manufacturability

FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.

Machinability

55 / 100
45 / 100

Machinability Rating (AISI 1212 = 100 %)

65%
50%

Weldability

80 / 100
30 / 100

Formability (cold)

78 / 100
40 / 100

Polishability

55 / 100
65 / 100

Same in both: Brazeability / Solderability 60 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

40 MJ/kg17,197 BTU/lb
55 MJ/kg23,646 BTU/lb

Embodied Carbon (primary production)

2.9 kg CO₂/kg
5 kg CO₂/kg

Embodied Water

90 L/kg10.8 gal/lb
150 L/kg18 gal/lb

Typical Recycled Content

65%
50%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

58 kN·m/kg
73 kN·m/kg

Specific Stiffness (E / density)

26 MN·m/kg
26.7 MN·m/kg

Modulus of Resilience

156 kJ/m³
306 kJ/m³

Thermal Diffusivity

7 mm²/s
5.6 mm²/s

Thermal Shock Resistance Index

5
6

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.

3005007001,0001,5002,0007.27.47.67.888.2Density (g/cm³)Yield strength (MPa) — log scale409446

Manufacturing and finishing

Capability409446
Default conditionAnnealedAnnealed
Relative cost$$$ Premium$$$ Premium
Min. machined wall0.8 mm0.8 mm
Best machined surfaceRa 1.6 µmRa 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 446 — frequently asked

Is 446 stronger than 409?

Yes. 446 has a typical yield strength of 350 MPa (50.8 ksi) against 250 MPa (36.3 ksi) for 409 — about 40% more. Tensile strength is 550 MPa (79.8 ksi) vs 450 MPa (65.3 ksi).

Which is cheaper, 409 or 446?

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 446?

409. Its machinability rates good (55/100) against fair (45/100) for 446; for welding the order is 409 first (very good, 80/100) then 446 (poor, 30/100).

Ready to make it?

Upload a CAD file and FabDigit prices the part in 409 and 446 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.