Stainless Steel 409
AISI/SAE 409 · UNS S40900 · EN 1.4512, X2CrTi12 · JIS SUS409L, SUS409 · GB 06Cr11Ti, 022Cr12Ti
409 is an economical 11–12 % Cr titanium-stabilized ferritic stainless (UNS S40900, 1.4512 / X2CrTi12, SUS409L) and the workhorse grade for automotive exhaust systems because of its low cost and good weldability.
Values for the Annealed condition
409 tempers and conditions
409 is supplied in 3 conditions, soft to hard. Annealed is the default FabDigit quotes; the values on this page are for it.
Compare all 3 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
AnnealedDefault mill annealed (ASTM A240 / EN 1.4512 solution condition) | Standard stocked condition for exhaust sheet, strip and tube; best formability and weldability. | 250 | 450 | 30 | 150 HB | 2.9 % IACS |
lightly cold worked strip | Small amount of cold reduction to raise yield strength and suppress stretcher strains in roll-formed tube. | 330 | 490 | 22 | 170 HB | 2.9 % IACS |
bar and wire, as-drawn (not re-annealed) | Bar/wire condition with higher strength and better machining chip control; ductility reduced. | 450 | 550 | 15 | 195 HB | 2.9 % IACS |
Supply forms, finishes and certifications
Ways 409 is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
Welded Tube Annealed | Welded tube, bright/box annealed after welding | Supply form |
2B | Cold rolled, annealed, pickled and skin passed | Surface finish |
2D | Cold rolled, annealed and pickled | Surface finish |
HRAP | No.1 / HRAP | Surface finish |
What is 409?
409 is an economical 11–12 % Cr titanium-stabilized ferritic stainless (UNS S40900, 1.4512 / X2CrTi12, SUS409L) and the workhorse grade for automotive exhaust systems because of its low cost and good weldability. Annealed material gives 250 MPa yield, 450 MPa tensile, 30 % elongation and 150 HB (80 HRB) with service to 675 °C, supplied as 2B, 2D and temper-rolled sheet, HRAP coil, cold-drawn bar and annealed welded tube. It surface-rusts in wet or salted service and has less stretch formability than austenitics; 439 or 441 give better forming and hot strength, 304 where appearance matters. 409 has a density of 7.7 g/cm³ (0.278 lb/in³), lighter than 83% of stainless steel grades. It melts at 1,482°C (2,700 °F). 409 has a yield strength of 250 MPa (36.3 ksi) and a tensile strength of 450 MPa (65.3 ksi) — weaker than 91% of stainless steel grades. Elongation at break is 30% and the elastic modulus is 200 GPa (29 Msi).
What is 409 used for?
- Automotive exhaust systems
- Muffler shells and baffles
- Catalytic converter shells
- Exhaust manifolds and downpipes
- Tailpipes and welded exhaust tubing
- Heat shields
- Furnace and appliance flues
- Agricultural equipment panels
Advantages
- Low embodied carbon — 2.9 kg CO₂/kg, better than 98% of stainless steel grades
- Easy to machine — 55/100, better than 94% of stainless steel grades
- Forms and bends easily — 78/100, better than 90% of stainless steel grades
- Conducts heat well — 24.9 W/m·K (14.4 BTU/hr·ft·°F), better than 87% of stainless steel grades
- High electrical conductivity — 2.9 % IACS, better than 87% of stainless steel grades
Limitations
- Needs corrosion protection — 40/100, worse than 93% of stainless steel grades
- Low strength — 250 MPa (36.3 ksi), worse than 91% of stainless steel grades
- Hard to polish — 55/100, worse than 89% of stainless steel grades
409 properties
Typical room-temperature values for 409-Annealed; bars are the position among stainless steel grades.
Physical3
409 has a density of 7.7 g/cm³ (0.278 lb/in³), lighter than 83% of stainless steel grades. It melts at 1,482°C (2,700 °F).
Mechanical15
409 has a yield strength of 250 MPa (36.3 ksi) and a tensile strength of 450 MPa (65.3 ksi) — weaker than 91% of stainless steel grades. Elongation at break is 30% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
409 is rated for continuous service to 675°C (1,247 °F). It conducts heat at 24.9 W/m·K (14.4 BTU/hr·ft·°F), better than 87% of stainless steel grades. Thermal expansion is 11.7 µm/m·K (6.5 µin/in·°F).
Electrical3
409 conducts electricity at 2.9 % IACS, better than 87% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is fair (40/100), worse than 93% of stainless steel grades.
Sustainability4
Producing a kilogram of 409 takes about 40 MJ of energy and emits 2.9 kg of CO₂ — less than 97% of stainless steel grades. Typical recycled content is 65%.
Manufacturability7
409's machinability is good (55/100, better than 94% of stainless steel grades); weldability very good (80/100); formability very good (78/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the stainless steel family
Yield strength against density for every stainless steel grade FabDigit runs. 409 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with 409
Is 409 easy to machine?
Machines more easily than 304 (softer, lower work hardening) but chips are stringy — use sharp positive-rake carbide, rigid setup and generous coolant.
Can 409 be welded?
Excellent weldability with GTAW/GMAW/laser; titanium stabilization avoids sensitization, but keep heat input low to limit weld-metal grain coarsening and use 409Cb/430Ti or 308L filler.
Can 409 be formed, bent or molded?
Good deep-draw and roll-form behaviour in annealed 2B; less stretch formability than austenitics, so allow larger bend radii and watch for ridging/roping.
Manufacturability
The process limits FabDigit applies to 409. Every 409 part is priced by an engineer; design inside these and the quote comes back without a redesign loop.
CNC machining
| Machinability | Better55 / 100 |
|---|---|
| ISO material group | M.4 |
| Cutting speed (rough / finish) | 140 / 170 m/min |
| Minimum wall | 0.8 mm |
| Minimum internal radius | 1.5 mm |
| Drill depth limit | 4× diameter |
| Best surface (machined / polished) | Ra 1.6 / — |
| Hardenable after machining | No |
Sheet metal
| Formability | Better78 / 100 |
|---|---|
| Weldability | Fair80 / 100 |
| Bendable | Yes |
409 chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| CS40900 modern; older 409 allowed 0.08 max | ≤ 0.03 | 0.02 |
| Mn | ≤ 1 | 0.4 |
| Si | ≤ 1 | 0.5 |
| P | ≤ 0.04 | 0.03 |
| S | ≤ 0.02 | 0 |
| CrEN 1.4512: 10.5–12.5 | 10.5 – 11.75 | 11.2 |
| Ni | ≤ 0.5 | 0.2 |
| Ti6×(C+N) min; EN 1.4512 max 0.65 | 0.17 – 0.5 | 0.25 |
| N | ≤ 0.03 | 0.02 |
| Fe | balance |
What surface finishes work on 409?
Usually left bare, shot blasted or painted/aluminized; can be brushed or polished, though Ti inclusions and ferrite banding limit mirror finishes.
Surface treatments FabDigit runs on stainless steel parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
Plating
Organic Coating
CVD Coating
Black / Phosphate
Thermal Spray
Equivalent designations
Standards and trade names that resolve to Stainless Steel 409 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- S40900
- EN / DIN / Werkstoff-Nr.
- 1.4512X2CrTi12
- GB (China)
- 06Cr11Ti022Cr12Ti022Cr11Ti0Cr11Ti
- JIS
- SUS409LSUS409
How much does 409 cost?
409 is a premium-cost stainless steel ($$$), pricier than about 58% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
409 — frequently asked
What is 409 used for?
409 is typically used for automotive exhaust systems, muffler shells and baffles, catalytic converter shells, exhaust manifolds and downpipes, tailpipes and welded exhaust tubing and heat shields. In short: automotive exhaust ferritic stainless.
What is the yield strength of 409?
409 has a typical yield strength of 250 MPa (36.3 ksi) and a tensile strength of 450 MPa (65.3 ksi) — weaker than 91% of stainless steel grades. Strength varies by condition: see the 3 listed tempers.
Is 409 easy to machine?
Reasonably — machinability is rated good (55/100, better than 94% of stainless steel grades). Machines more easily than 304 (softer, lower work hardening) but chips are stringy — use sharp positive-rake carbide, rigid setup and generous coolant.
Can 409 be welded?
Yes — weldability is rated very good (80/100). Excellent weldability with GTAW/GMAW/laser; titanium stabilization avoids sensitization, but keep heat input low to limit weld-metal grain coarsening and use 409Cb/430Ti or 308L filler.
What surface finishes work on 409?
Usually left bare, shot blasted or painted/aluminized; can be brushed or polished, though Ti inclusions and ferrite banding limit mirror finishes.
Can 409 be formed, bent or molded?
Good deep-draw and roll-form behaviour in annealed 2B; less stretch formability than austenitics, so allow larger bend radii and watch for ridging/roping.
What is the maximum service temperature of 409?
409 is rated for continuous use to about 675°C (1,247 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does 409 cost?
409 is a premium-cost stainless steel ($$$), pricier than about 58% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Can FabDigit make parts in 409?
Yes — 409 is available for CNC machining and sheet metal; every part is priced by an engineer rather than instantly. Upload a STEP file to get a price and a DFM check.
Sources
- ASTM A240/A240M — Chromium and Chromium-Nickel Stainless Steel Plate, Sheet, and Strip — ASTM International (2023)
- EN 10088-2 — Stainless steels, Part 2: technical delivery conditions for sheet/plate and strip (1.4512) — CEN (2014)
- GB/T 3280 (022Cr11Ti) — SAC (2015)
- 409 Ferritic Stainless Steel Product Data Sheet — AK Steel / Cleveland-Cliffs (2018)
- ASM Handbook Vol.1: Properties and Selection — Irons, Steels and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol.16: Machining — ASM International (1989)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.