Description
Basic Material Introduction
409 (UNS S40900, EN 1.4512, JIS SUH409, X6CrTi12) is a titanium-stabilized ferritic stainless steel, developed primarily for high-temperature exhaust systems.
Matrix: Ferritic (BCC structure, magnetic)
Near-zero nickel content, much lower cost than 304/316 austenitic stainless steel
Titanium addition eliminates intergranular corrosion after welding, solves welding sensitization problem
| Element | C | Si | Mn | Cr | Ni | Ti | P/S |
|---|---|---|---|---|---|---|---|
| Content | ≤0.08 | ≤1.00 | ≤1.00 | 10.5–11.75 | ≤0.50 | ≥6×C | ≤0.045 |
Core Performance Features
High-temperature oxidation resistance (core advantage)
Continuous service: ≤675℃
Intermittent thermal cycling: up to 815℃
Far better anti-scaling than carbon steel; ideal for exhaust high-heat cycles
Corrosion resistance
Better than carbon steel & 410; much weaker than 304
Only suitable for dry air, high-temp flue gas; prone to surface rust in coastal/salt spray environments
Not for decorative, food, marine or chemical piping
Machining & Welding
Good formability: bending, mandrel bending, stamping for exhaust parts
Excellent weldability (Ti stabilizes carbon; no carbide precipitation at weld seams)
No heat hardening; only slight work hardening after cold forming
Lower thermal expansion than 304, less thermal fatigue under repeated heating/cooling
Cost advantage
20%–30% cheaper than 304 stainless pipe due to no nickel alloying
Products Description
Pipe Forms
Seamless 409 stainless pipe (hot rolled / cold drawn)
Welded 409 stainless tube (ERW straight seam)
Shapes: round tube, square/rectangular tube, special exhaust bent tubes
Size Range
Outer diameter: 4mm ~ 800mm
Wall thickness: 1mm ~ 150mm (SCH10–XXS)
Standard length: 4m / 6m / 12m or custom cut
Surface finish: No.1 hot rolled black, 2B cold rolled matte, pickled finish
Executive Standards
ASTM A268 (ferritic stainless seamless & welded tube)
ASTM A554 (welded stainless mechanical tubing)
EN 10216-5, EN 10217-7
GB/T 12771, GB/T 13296
Products Description
Automotive (largest market)
Exhaust manifold, catalytic converter shell, muffler, tailpipe, heat shield, exhaust hangers (OEM factory standard material)
Industrial high-temperature piping
Generator exhaust, boiler flue pipe, furnace cooling tubes, low-temperature heat exchangers
General machinery
Agricultural equipment exhaust, transformer casings, low-cost high-temperature structural brackets
409 VS 304 Stainless Pipe Comparison
| Item | 409 Stainless Pipe | 304 Stainless Pipe |
|---|---|---|
| Structure | Ferritic, magnetic | Austenitic, non-magnetic |
| Alloy | ~11% Cr, no Ni | 18%Cr+8%Ni (18/8) |
| High temp oxidation | Excellent for exhaust cycles | Good, but higher thermal expansion |
| Corrosion resistance | Moderate, surface rust in humid/salt air | Superior, suitable for wet & mild chemical environments |
| Price | Low (economical) | High |
| Appearance | Not decorative, easy to form faint rust spots | Polishable, bright surface |
| Typical use | Car exhaust, industrial flue gas | Food, plumbing, decoration, marine equipment |
Common Questions and Answers:
Hot Tags: 409l stainless steel pipe, China 409l stainless steel pipe manufacturers, suppliers, factory, austenitic stainless steel assessment, austenitic stainless steel international supply chain, austenitic stainless steel kitchen grade, austenitic stainless steel national supply chain, austenitic stainless steel price, austenitic stainless steel special purpose grade
