Stainless Steel 409 · temper · default condition
Stainless Steel 409 Annealed
Properties of the Annealed condition, compared with the other 409 tempers.
Standard stocked condition for exhaust sheet, strip and tube; best formability and weldability.
What is 409 Annealed?
409 Annealed is 409 in the Annealed temper — standard stocked condition for exhaust sheet, strip and tube; best formability and weldability. 409 Annealed 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). 409 Annealed 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).
Advantages
- Low embodied carbon — 2.9 kg CO₂/kg, better than 98% of stainless steel grades
- Easy to machine — 55/100, better than 95% 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 88% 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 Annealed properties
Typical room-temperature values for 409 Annealed — 10 properties are specific to this condition; the rest are grade-level values shared by every 409 temper. Each bar shows where the value sits among the stainless steel grades in FabDigit's library — further right is higher.
Physical3
409 Annealed 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).
Mechanical14
409 Annealed 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 Annealed 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 88% of stainless steel grades. Thermal expansion is 11.7 µm/m·K (6.5 µin/in·°F).
Electrical3
409 Annealed 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 Annealed 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 Annealed's machinability is good (55/100, better than 95% 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.
Other 409 tempers and conditions
409 is also supplied in 6 other conditions. The full side-by-side table is on the 409 overview.
- AnnealedDefaultStandard stocked condition for exhaust sheet, strip and tube; best formability and weldability.250 MPa yield · 150 HB
Working with 409 Annealed
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.
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.
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 | — |
409 Annealed — frequently asked
What is 409 Annealed used for?
409 Annealed 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 Annealed?
409 Annealed 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 7 listed tempers.
Is 409 Annealed easy to machine?
Reasonably — machinability is rated good (55/100, better than 95% 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 Annealed 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 Annealed?
Usually left bare, shot blasted or painted/aluminized; can be brushed or polished, though Ti inclusions and ferrite banding limit mirror finishes.
Can 409 Annealed 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 Annealed?
409 Annealed 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.
What is the difference between 409 Annealed and 409 HRAP?
Annealed is the default condition — standard stocked condition for exhaust sheet, strip and tube; best formability and weldability. HRAP: heavier gauge hot band for tube strip, muffler shells and fabricated parts where surface finish is secondary. Yield strength is 250 MPa in Annealed versus 265 MPa in HRAP.
Can FabDigit make parts in 409 Annealed?
Yes — 409 Annealed is available for CNC machining and sheet metal with instant online pricing. 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. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.