Bar and Rod
Plate and Sheet
Strip
Pipe and Tube
Wire
Welding
Powder Material
Cast Products
Forged Products
Fittings
Fastening
Round Bar:
φ2–500 mm, 1–6 m length
Flat/Square Bar:
4–100 mm thickness/width
Hex Bar:
A/F 3–100 mm
Hollow Bar:
OD 20–300 mm
Sheet:
0.3–6 mm thickness
Medium Plate:
6–25 mm thickness
Heavy Plate:
25–100 mm thickness
Standard Strip:
0.05–3 mm thick,
10–600 mm wide
Precision strip:
0.01–0.5 mm thick,
tight tolerance ±0.005 mm
Foil:
0.005–0.1 mm thick
Seamless Tube:
OD 6–450 mm,
WT 1–50 mm,
1–12 m length
Welded Tube:
OD 10–600 mm,
WT 1–20 mm
Capillary Tube:
OD 1–10 mm,
WT 0.1–2 mm
Wire Form:
Cold Drawn Wire,
Bright Wire,
Spring Wire,
Fine Wire,
Ultra-fine Wire
General Diameter:
φ0.1–10 mm
Coil Weight:
50–500 kg,
customizable tolerance
Solid Wire:
φ0.8–4.0 mm
Flux-cored Wire:
φ1.2–4.0 mm
Welding Rod:
φ2.0–5.0 mm
Powder Form:
AM 3D Printing Powder,
Spherical Powder,
Gas-atomized Powder,
Water-atomized Powder
Particle Size:
10–150 μm
Sphericity:
≥90% for AM grade
Cast Ingot:
φ200–800 mm
Precision Casting:
min wall 0.5 mm
Cast Pipe:
OD 100–600 mm,
WT 10–50 mm
Forged Bar:
Φ35–500 mm
Forged Ring:
OD 200–2000 mm
Forging Weight:
1–5000 kg
Fittings Form:
Elbow, Tee, Reducer, Flange, Cap, Outlet, Lap Joint
Size range:
1/2''–24'' (DN15–DN600)
Wall thickness:
Sch10–Sch160, STD, XS, XXS
Pressure Class:
150–2500 LB
Fastening Form:
Bolt, Nut, Screw, Stud, Washer, Pin, Rivet
Metric: M3–M64
Imperial: #4–2.5''
Length: 6–500 mm
409L is a titanium-stabilized low-carbon ferritic stainless steel containing about 11% chromium. This datasheet presents the material within the American (ASTM / ASME / UNS) standard system.
With nominally 11% chromium and a titanium (and optionally niobium) stabilizing addition, 409L offers good resistance to oxidation and corrosion at elevated temperature at low cost, and is the standard "muffler grade" for automotive exhaust systems. The low carbon and titanium stabilization minimise sensitisation and improve weldability and formability relative to plain 409. Being ferritic, it is magnetic, cannot be hardened by heat treatment, does not work-harden significantly, and is largely insensitive to chloride stress-corrosion cracking. It may form a light surface rust film in service without loss of structural performance, and provides useful oxidation resistance to about 800 °C in exhaust applications.
Typical applications include automotive exhaust systems and catalytic converters, heat exchangers, agricultural equipment, and mildly corrosive structural components.
Typical values, annealed condition.
| Property | Value | Unit |
|---|---|---|
| Density | 7.7 | g/cm³ |
| Melting range | 1480–1530 | °C |
| Elastic modulus | 208 | GPa |
| Coefficient of thermal expansion (20–100 °C) | 11.0 | µm/m·°C |
| Thermal conductivity (100 °C) | 25.8 | W/m·K |
| Specific heat (20 °C) | 460 | J/kg·K |
| Structure | Ferritic | — |
Specified per ASTM A240 (UNS S40920 / S40910).
| Element | Symbol | Min % | Max % | Role in Alloy |
|---|---|---|---|---|
| Iron | Fe | Balance | — | Base element |
| Chromium | Cr | 10.5 | 11.7 | Corrosion / oxidation resistance |
| Titanium | Ti | 6×(C+N) | 0.50 | Stabiliser (S40920); ties up C and N |
| Niobium | Nb | — | 0.17 | Optional stabiliser (S40910) |
| Nickel | Ni | — | 0.50 | Residual |
| Manganese | Mn | — | 1.00 | Deoxidiser |
| Silicon | Si | — | 1.00 | Deoxidiser |
| Carbon | C | — | 0.030 | Low (stabilised, weldability) |
| Nitrogen | N | — | 0.030 | Low (stabilised) |
| Phosphorus | P | — | 0.040 | Residual impurity |
| Sulphur | S | — | 0.020 | Residual impurity |
Nominal: 11Cr titanium-stabilized low-carbon ferritic stainless steel.
Annealed condition, per ASTM A240 for UNS S40920 / S40910.
| Condition | Property | Value |
|---|---|---|
| Annealed | Tensile strength (UTS) | ≥380 MPa |
| Annealed | 0.2% yield strength | ≥205 MPa |
| Annealed | Elongation at break | ≥20 % |
| Annealed | Hardness | ≤88 HRB (≤179 HB) |
| — | Elastic modulus | 208 GPa |
Confirm against the mill test report.
| Environment | Performance | Notes |
|---|---|---|
| Atmospheric / general | Good | Far superior to carbon and low-alloy steels |
| Automotive exhaust gases | Very Good | Resists thickness loss; muffler-grade |
| Oxidation | Good | To approximately 800 °C in exhaust service |
| Chloride stress-corrosion cracking | Very Good | Ferritic — largely immune |
| Strong acids / salts | Limited | Below austenitic grades |
Corrosion resistance is well above carbon steel and adequate for exhaust and mildly corrosive service; a light surface rust film may form without affecting structural performance.
A ferritic grade; cannot be hardened by heat treatment. Properties are set by annealing.
Anneal Heat to 790–900 °C and air cool (or slow cool). Post-weld annealing at 760–815 °C improves weld ductility. Avoid prolonged exposure that promotes grain growth or 475 °C embrittlement.
Readily welded; a pre-heat of 150–260 °C is recommended for heavier sections. Austenitic fillers give a more ductile weld; titanium stabilization limits sensitisation.
| Welding Process | Applicability | Filler / Consumable |
|---|---|---|
| GTAW / TIG | Good | AWS A5.9 ER409 / ER409Cb, or 309 for ductility |
| GMAW / MIG | Good | ER409 / ER309 |
| SMAW / stick | Good | 409 or 309 electrode |
Avoid hydrogen- or nitrogen-bearing shielding gas (titanium addition). Post-weld anneal improves ductility on heavier sections.
Machining Guidelines
| Parameter | Recommendation |
|---|---|
| Machinability | Good; similar to other ferritic grades |
| Work hardening | Low rate — good formability |
| Coolant | Ample flood coolant |
Forming Processes
| Process | Notes |
|---|---|
| Cold forming | Good — roll forming, bending, mild pressing |
| Hot forming | ~1100–800 °C; anneal afterward |
| Industry | Typical Components | Key Requirements |
|---|---|---|
| Automotive | Exhaust systems, catalytic converters, mufflers | Oxidation resistance + low cost |
| Heat transfer | Heat exchangers, recuperators | Elevated-temperature corrosion resistance |
| Agriculture | Equipment, containers | Corrosion resistance + formability |
| General industrial | Structural and mildly corrosive components | Cost-effective stainless |
| Product Form | ASTM Standard | ASME Code |
|---|---|---|
| Plate, sheet and strip | ASTM A240 | ASME SA-240 |
| Welded tube | ASTM A268 / A268M | ASME SA-268 |
| Bar and shapes | ASTM A479 | ASME SA-479 |
| Welding consumables | AWS A5.9 ER409 / ER409Cb | — |
Titanium-stabilized low-carbon ferritic stainless steel. UNS S40920 / S40910.
| Grade | Cr % | Ti / Nb | C % | Best Used For |
|---|---|---|---|---|
| 409L | 10.5–11.7 | Ti | ≤0.03 | Muffler-grade ferritic; automotive exhaust |
| 410L | 11.5–13.5 | — | ≤0.03 | Utility ferritic; structural |
| 430 | 16–18 | — | ≤0.12 | General ferritic; trim, appliances |
| 439 | 17–19 | Ti | ≤0.03 | 18Cr-Ti ferritic; hot exhaust |
| 441 | 17.5–18.5 | Ti + Nb | ≤0.03 | 18Cr stabilized ferritic |
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