Stainless Steel ER409Cb AW+PWHT
Heat-treated state
GB ER409Nb
AW+PWHT = post-weld heat treated
Choose when maximum weld ductility/toughness and stress relief are needed on heavier ferritic sections.
Values for the AW+PWHT condition
Other ER409Cb tempers and conditions
ER409Cb is listed in 2 conditions; see the grade overview at ER409Cb.
- AW+PWHT
- AW
Compare all 2 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
AW+PWHTThis page Post-weld heat treated | Choose when maximum weld ductility/toughness and stress relief are needed on heavier ferritic sections. | 300 | 450 | 26 | 150 HB | 3 % IACS |
AWDefault As-welded deposit | Standard condition for exhaust and thin-gauge ferritic stainless joints welded and put into service without post-weld heat treatment. | 330 | 480 | 22 | 165 HB | 2.9 % IACS |
What is ER409Cb AW+PWHT?
ER409Cb AW+PWHT is ER409Cb heat treated to AW+PWHT — choose when maximum weld ductility/toughness and stress relief are needed on heavier ferritic sections. ER409Cb AW+PWHT has a yield strength of 300 MPa (43.5 ksi) and a tensile strength of 450 MPa (65.3 ksi) — weaker than 68% of stainless steel grades. Elongation at break is 26% and the elastic modulus is 200 GPa (29 Msi). ER409Cb AW+PWHT has a density of 7.7 g/cm³ (0.278 lb/in³), lighter than 83% of stainless steel grades. It melts at 1,480°C (2,696 °F). AW is the default condition FabDigit quotes; AW+PWHT is available on request or by drawing note.
Advantages
- Easy to machine — 60/100, better than 98% of stainless steel grades
- Conducts heat well — 25.2 W/m·K (14.6 BTU/hr·ft·°F), better than 95% of stainless steel grades
- High electrical conductivity — 3 % IACS, better than 95% of stainless steel grades
- Low embodied carbon — 3.4 kg CO₂/kg, better than 91% of stainless steel grades
- Readily welded — 80/100, better than 80% of stainless steel grades
Limitations
- Hard to polish — 55/100, worse than 89% of stainless steel grades
- Low fracture toughness — 65 MPa·√m (59.2 ksi·√in), worse than 85% of stainless steel grades
- Needs corrosion protection — 48/100, worse than 80% of stainless steel grades
ER409Cb AW+PWHT properties
Typical room-temperature values for ER409Cb AW+PWHT; 22 are specific to this condition. Other listed values are ER409Cb reference data and may not represent this condition. Bars are the position among stainless steel grades.
Physical3
ER409Cb AW+PWHT has a density of 7.7 g/cm³ (0.278 lb/in³), lighter than 83% of stainless steel grades. It melts at 1,480°C (2,696 °F).
Mechanical16
ER409Cb AW+PWHT has a yield strength of 300 MPa (43.5 ksi) and a tensile strength of 450 MPa (65.3 ksi) — weaker than 68% of stainless steel grades. Elongation at break is 26% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
ER409Cb AW+PWHT is rated for continuous service to 675°C (1,247 °F). It conducts heat at 25.2 W/m·K (14.6 BTU/hr·ft·°F), better than 95% of stainless steel grades. Thermal expansion is 11.7 µm/m·K (6.5 µin/in·°F).
Electrical3
ER409Cb AW+PWHT conducts electricity at 3 % IACS, better than 95% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is fair (48/100), worse than 80% of stainless steel grades.
Sustainability4
Producing a kilogram of ER409Cb AW+PWHT takes about 45 MJ of energy and emits 3.4 kg of CO₂ — less than 91% of stainless steel grades. Typical recycled content is 60%.
Manufacturability6
ER409Cb AW+PWHT's machinability is good (60/100, better than 98% of stainless steel grades); weldability very good (80/100); formability good (60/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with ER409Cb AW+PWHT
Is ER409Cb easy to machine?
Weld metal machines like Type 409 ferritic stainless — use sharp carbide, positive rake and generous feed to avoid work-hardened smearing; expect gummy chips.
Can ER409Cb be welded?
Use GTAW or short-arc/pulsed GMAW with Ar or Ar+2%CO₂, low heat input and interpass ≤150 °C to limit ferrite grain coarsening; no preheat needed on thin gauge, 100–200 °C preheat on sections >10 mm.
Can ER409Cb be formed, bent or molded?
Supplied as cold-drawn wire; keep spool clean and dry, and avoid tight de-reeling radii that cause feedability problems or wire kinking.
What surface finishes work on ER409Cb?
Pickle/passivate or wire-brush with stainless-only tools after welding to restore the passive film; weld metal takes paint and aluminized coatings well but will surface-rust if scale is left on.
ER409Cb 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 |
|---|---|---|
| CAWS A5.9 max | ≤ 0.08 | 0.03 |
| Cr | 10.5 – 13.5 | 12 |
| Ni | ≤ 0.6 | 0.25 |
| NbNb+Ta; stabilizer | 0.5 – 1.5 | 0.9 |
| Mn | ≤ 0.8 | 0.5 |
| Si | ≤ 1 | 0.5 |
| Tiresidual only in Nb-stabilized type | ≤ 0.15 | — |
| Cu | ≤ 0.75 | — |
| P | ≤ 0.04 | — |
| S | ≤ 0.03 | — |
| Fe | balance | — |
ER409Cb AW+PWHT — frequently asked
What is ER409Cb AW+PWHT used for?
ER409Cb AW+PWHT is typically used for automotive exhaust component welding, muffler and resonator shell seams, catalytic converter and downpipe joints, 409-grade tube and flange welds, heat shields and exhaust brackets and flue and vent sheet fabrication. In short: nb-stabilized 409 filler; better weld ductility than ER409; exhaust-grade ferritic wire.
What is the yield strength of ER409Cb AW+PWHT?
ER409Cb AW+PWHT has a typical yield strength of 300 MPa (43.5 ksi) and a tensile strength of 450 MPa (65.3 ksi) — weaker than 68% of stainless steel grades. Strength varies by condition: see the 2 listed tempers.
Is ER409Cb AW+PWHT easy to machine?
Reasonably — machinability is rated good (60/100, better than 98% of stainless steel grades). Weld metal machines like Type 409 ferritic stainless — use sharp carbide, positive rake and generous feed to avoid work-hardened smearing; expect gummy chips.
Can ER409Cb AW+PWHT be welded?
Yes — weldability is rated very good (80/100). Use GTAW or short-arc/pulsed GMAW with Ar or Ar+2%CO₂, low heat input and interpass ≤150 °C to limit ferrite grain coarsening; no preheat needed on thin gauge, 100–200 °C preheat on sections >10 mm.
What surface finishes work on ER409Cb AW+PWHT?
Pickle/passivate or wire-brush with stainless-only tools after welding to restore the passive film; weld metal takes paint and aluminized coatings well but will surface-rust if scale is left on.
Can ER409Cb AW+PWHT be formed, bent or molded?
Supplied as cold-drawn wire; keep spool clean and dry, and avoid tight de-reeling radii that cause feedability problems or wire kinking.
What is the maximum service temperature of ER409Cb AW+PWHT?
ER409Cb AW+PWHT 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.
Sources
- AWS A5.9/A5.9M — Bare Stainless Steel Welding Electrodes and Rods — AWS (2017)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol.6 — Welding, Brazing, and Soldering (ferritic stainless welding) — ASM International (1993)
- Stainless ferritic filler metal datasheets (ER409Cb/ER409Nb) — welding consumable producers (2023)
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.