SS409 is a low-cost ferritic stainless steel with about 11% chromium, no nickel and a little titanium. It resists heat and exhaust-gas corrosion well enough for silencers, exhaust pipes and catalytic converter shells, at a much lower price than SS304. It is magnetic and will show light surface rust in wet, salty places.
Quick facts
- Type
- Ferritic stainless steel (titanium stabilised)
- Chromium
- About 10.5–11.7%
- Nickel
- Up to about 0.5%
- Magnetic
- Yes
- Heat resistance
- Good scaling resistance up to about 700–800 °C
- Weldability
- Good in thin sections
Equivalent grades
| Standard | Grade |
|---|---|
| AISI / ASTM | 409 / 409L |
| EN | 1.4512 (X2CrTi12) |
| UNS | S40910 / S40920 / S40930 |
| JIS | SUH409L |
Equivalents are close, not identical. Name the grade and standard on the drawing.
Typical chemical composition
| Element | % |
|---|---|
| Carbon (C) | 0.03 max (409L) |
| Chromium (Cr) | About 10.5–11.7 |
| Titanium (Ti) | About 6 × C to 0.65 |
| Manganese (Mn) | Up to 1 |
| Nickel (Ni) | Up to 0.5 |
Values are typical. The exact limits depend on the standard and supplier; ask for the mill test certificate when it matters.
SS409 or SS304?
| SS409 | SS304 | |
|---|---|---|
| Cost | Lower | Higher |
| Corrosion resistance | Moderate, surface rust possible | Good |
| Magnetic | Yes | No |
| Forming | Fair | Excellent |
| Typical use | Exhausts, silencers | Food, tanks, sheet work |
Typical uses
- Exhaust pipes and silencers
- Catalytic converter shells
- Heat shields
- Agricultural and transport equipment
- Generator and DG set exhausts
Need parts made in SS409 stainless steel?
Post your requirement free. Workshops that take your kind of work see it and get in touch. You only talk to the ones that fit.
Get startedRelated
Related job work
Questions
- Is SS409 really stainless?
- Yes, it has enough chromium to count as stainless, but only just. It resists heat and exhaust gas well and may show light surface rust outdoors.
- Why is SS409 used for exhausts instead of SS304?
- It handles exhaust heat and condensate well enough and costs much less, because it has almost no nickel.
- Is SS409 magnetic?
- Yes. Like other ferritic stainless steels, it is magnetic.
The figures on this page are typical values for guidance, written by Diemeco from standard engineering practice. They are not a specification: confirm grades and properties with the relevant standard or the supplier's mill test certificate, and tolerances with your workshop. Last checked 22 October 2026.