Guides/Comparisons
409 vs 430 ferritic stainless steel
409-vs-430-stainless-steelStainless steel 409 and Stainless steel 430 at a glance
This page compares Stainless steel 409 and Stainless steel 430 using only values that carry a source, a test condition and an evidence level. Ranges run across temper, heat treatment and product form, measured at room temperature where the source says so.
- Composition: Chromium (409 10.5 to 11.8%; 430 16 to 18%), Carbon (409 up to 0.08%; 430 up to 0.12%), Nickel (409 up to 0.5%; 430 up to 0.75%), Molybdenum (409 up to 0.35%; 430 up to 0.5%).
- Yield strength: the ranges overlap (409 170 to 255 MPa; 430 207 to 386 MPa).
- Tensile strength: the ranges overlap (409 380 to 560 MPa; 430 400 to 630 MPa).
- Density: the ranges overlap (409 7.6 to 7.75 g/cm³; 430 7.7 to 7.74 g/cm³).
- Young's modulus: 409 is higher (409 208 to 220 GPa; 430 200 GPa), a difference of under 10% at the midpoint.
- Thermal conductivity: the ranges overlap (409 25 to 25.8 W/(m·K); 430 23.9 to 26 W/(m·K)).
- Thermal expansion: the ranges overlap (409 10.5 to 12 ppm/K; 430 10.3 to 11.9 ppm/K).
- Yield strength for each unit of density (calculated from each grade's midpoint values): Stainless steel 409 27.7 MPa per g/cm³; Stainless steel 430 38.4 MPa per g/cm³.
"Higher" means the whole range is higher, not just one value. Where a value is a specified minimum, the table says "at least".
Side by side
| Property | Stainless steel 409 | Stainless steel 430 |
|---|---|---|
| Yield strength | 170 to 255 MPa | 207 to 386 MPa |
| Tensile strength | 380 to 560 MPa | 400 to 630 MPa |
| Density | 7.6 to 7.75 g/cm³ | 7.7 to 7.74 g/cm³ |
| Young's modulus | 208 to 220 GPa | 200 GPa |
| Thermal conductivity | 25 to 25.8 W/(m·K) | 23.9 to 26 W/(m·K) |
| Melting point | no data | 1,425 to 1,510 °C |
| Service temperature | no data | 730 to 870 °C |
| Thermal expansion | 10.5 to 12 ppm/K | 10.3 to 11.9 ppm/K |
| Yield strength per densitycalculated | 27.7 MPa per g/cm³ | 38.4 MPa per g/cm³ |
Composition
| Element | Stainless steel 409 | Stainless steel 430 |
|---|---|---|
| Iron | balance | balance |
| Chromium | 10.5 to 11.8% | 16 to 18% |
| Titanium | up to 0.75% | not listed |
| Carbon | up to 0.08% | up to 0.12% |
| Nitrogen | up to 0.03% | not listed |
| Manganese | up to 1% | up to 1% |
| Silicon | up to 1% | up to 1% |
| Nickel | up to 0.5% | up to 0.75% |
| Molybdenum | up to 0.35% | up to 0.5% |
| Copper | up to 0.35% | not listed |
| Phosphorus | up to 0.045% | up to 0.04% |
| Sulfur | up to 0.03% | up to 0.03% |
Shares are as printed in the sources, by weight.
When to use which
| Material | Best for | Weakest at |
|---|---|---|
| Stainless steel 409 | Automotive exhaust systems and heat exchangers, where corrosion protection is needed beyond carbon steel (Combined Metals) | Pitting and intergranular corrosion: Outokumpu prints a critical pitting temperature below 10 °C and N/N for intergranular corrosion, and Aalco limits welded sheet to about 2.5 mm thick |
| Stainless steel 430 | Sinks, appliance trim and architectural cladding, where economy and moderate corrosion resistance matter more than strength (ATI) | Welds and sea water. Welds lose ductility and corrosion resistance, and the datasheet says the grade is not resistant to sea water (Deutsche Edelstahlwerke) |
Where each is used
| Material | Use |
|---|---|
| Stainless steel 409 | Automotive exhaust systems, mufflers and pipes |
| Stainless steel 409 | Exhaust manifolds, down-pipes, converter casings and mufflers |
| Stainless steel 409 | Heat exchangers |
| Stainless steel 430 | Architectural trim, industrial roofing and wall cladding |
| Stainless steel 430 | Sinks, sink rims, range hoods, dishwashers and appliance trim |
| Stainless steel 430 | Automotive trim and appliance components |