Type 441 Stainless Steel is a ferritic stainless steel which provides good high-temperature strength (exceeding that of Types 409 and 439 Stainless Steels) plus good corrosion resistance in many exhaust gas environments (equivalent to Type 439 and 18 Cr-Cb Stainless Steels). . Ferritic steels are not inherently strong at elevated temperatures, but columbium additions coupled with appropriate solution annealing markedly improve long-time creep rupture strength. Type 441 is dual stabilized with niobium and titanium to provide good weld ductility and resistance to intergranular corrosion in the weld heat affected zone.
Sheet, Strip
ASTM A240 (S43940) and EN 10088-2 (1.4509)
Automotive exhaust tube and components
| Element | UNS 43940 | EN 1.4509 |
|---|---|---|
| Carbon | 0.030 max. | 0.030 max. |
| Manganese | 1.00 max. | 1.00 max. |
| Sulfur | 0.015 max. | 0.015 max. |
| Phosphorus | 0.040 max | 0.040 max. |
| Silicon | 1.00 max. | 1.00 max. |
| Chromium | 17.5 – 18.5 | 17.5 – 18.5 |
| Titanium | 0.10 – 0.60 | 0.10 – 0.60 |
| Nitrogen | – | 0.045 max. |
| Niobium | 0.30+(9xC) min. | 0.30+(9xC) min.– 1.00 max. |
| Type | Yield Strength 0.2% offset (KSI) | Tensile Strength (KSI) | % Elongation (2″ Gauge length) |
|---|---|---|---|
| UNS S43940 | 36 min. | 62 min. | 18 min. |
| EN 1.4509 | 36 min. | 62 – 91 | 18 min. |