Stainless Steel ER309Cb-AW (As-welded deposit)
Heat-treated state · default condition
Standard condition for classification testing and most overlay/dissimilar-joint service — use unless PWHT is imposed by the base metal.
Values for the AW condition
Other ER309Cb tempers and conditions
ER309Cb is listed in 3 conditions; see the grade overview at ER309Cb.
Compare all 3 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
As-welded submerged-arc / strip-cladding overlay deposit | Pick for high-deposition SAW wire or strip cladding of pressure-vessel steel; higher heat input gives slightly lower strength and toughness scatter. | 385 | 570 | 33 | 185 HB | 2.2 % IACS |
Post-weld heat treated | Use when the Cr-Mo or C-steel base metal mandates PWHT; Nb stabilization keeps the overlay resistant to sensitization, but some ferrite may transform toward sigma. | 400 | 580 | 30 | 195 HB | 2.2 % IACS |
AWDefaultThis page As-welded deposit | Standard condition for classification testing and most overlay/dissimilar-joint service — use unless PWHT is imposed by the base metal. | 410 | 600 | 35 | 190 HB | 2.2 % IACS |
What is ER309Cb-AW?
ER309Cb-AW is ER309Cb heat treated to AW — standard condition for classification testing and most overlay/dissimilar-joint service — use unless PWHT is imposed by the base metal. ER309Cb-AW has a yield strength of 410 MPa (59.5 ksi) and a tensile strength of 600 MPa (87 ksi) — stronger than 60% of stainless steel grades. Elongation at break is 35% and the elastic modulus is 196 GPa (28.4 Msi). ER309Cb-AW has a density of 7.9 g/cm³ (0.285 lb/in³), heavier than 68% of stainless steel grades. It melts at 1,400°C (2,552 °F).
Advantages
- Readily welded — 88/100, better than 91% of stainless steel grades
Limitations
- Hard to polish — 60/100, worse than 80% of stainless steel grades
ER309Cb-AW properties
Typical room-temperature values for ER309Cb-AW; 23 are specific to this condition. Other listed values are ER309Cb reference data and may not represent this condition. Bars are the position among stainless steel grades.
Physical3
ER309Cb-AW has a density of 7.9 g/cm³ (0.285 lb/in³), heavier than 68% of stainless steel grades. It melts at 1,400°C (2,552 °F).
Mechanical16
ER309Cb-AW has a yield strength of 410 MPa (59.5 ksi) and a tensile strength of 600 MPa (87 ksi) — stronger than 60% of stainless steel grades. Elongation at break is 35% and the elastic modulus is 196 GPa (28.4 Msi).
Thermal6
ER309Cb-AW is rated for continuous service to 800°C (1,472 °F). It conducts heat at 15 W/m·K (8.67 BTU/hr·ft·°F), worse than 59% of stainless steel grades. Thermal expansion is 15.5 µm/m·K (8.61 µin/in·°F).
Electrical3
ER309Cb-AW conducts electricity at 2.2 % IACS, worse than 61% of stainless steel grades.
Chemical & Environmental2
Corrosion resistance is good (68/100), better than 63% of stainless steel grades.
Sustainability4
Producing a kilogram of ER309Cb-AW takes about 55 MJ of energy and emits 4.8 kg of CO₂ — more than 50% of stainless steel grades. Typical recycled content is 55%.
Manufacturability7
ER309Cb-AW's machinability is poor (32/100, worse than 62% of stainless steel grades); weldability excellent (88/100); formability good (55/100).
Common Calculations5
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with ER309Cb-AW
Is ER309Cb easy to machine?
Overlay machines like Type 309/347: low speed, heavy positive-rake carbide, rigid setup and flood coolant to fight work hardening and gumming.
Can ER309Cb be welded?
Run GTAW/GMAW/SAW with Ar or Ar+2%CO2 (or 100% Ar + He for TIG), interpass ≤150 °C and limited heat input to hold ferrite and avoid hot cracking; ideal buffer layer under 347/321 or before nickel-alloy cover passes.
Can ER309Cb be formed, bent or molded?
Supplied as cold-drawn wire; bend TIG rods only gently — the deposit itself work-hardens rapidly and is normally not cold formed.
What surface finishes work on ER309Cb?
Grind, pickle and passivate the overlay to restore the passive film; avoid carbon-steel tooling contamination, no anodizing applies.
ER309Cb 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 |
|---|---|---|
| C≤0.03 for the low-carbon ER309LNb variant | ≤ 0.12 | 0.06 |
| Cr | 23 – 25 | 24 |
| Ni | 12 – 14 | 13 |
| NbNb+Ta reported as Cb; stabilizing addition | 0.7 – 1 | 0.85 |
| Mn | 1 – 2.5 | 1.8 |
| SiSi-enhanced ER309LNbSi types run 0.65–1.00 | 0.3 – 0.65 | 0.45 |
| Moresidual | ≤ 0.75 | — |
| Curesidual | ≤ 0.75 | — |
| P | ≤ 0.03 | — |
| S | ≤ 0.03 | — |
| Fe | balance | — |
ER309Cb-AW — frequently asked
What is ER309Cb-AW used for?
ER309Cb-AW is typically used for stabilized cladding and weld overlays, buffer layers under 347 or 321 weld metal, dissimilar-metal joints requiring Nb stabilization, transition welds ahead of nickel-alloy cover passes, submerged-arc overlay of pressure vessel shells and repair of stabilized stainless-clad equipment. In short: stabilized 309 overlay wire; buffer layer for 347/321; resists intergranular attack.
What is the yield strength of ER309Cb-AW?
ER309Cb-AW has a typical yield strength of 410 MPa (59.5 ksi) and a tensile strength of 600 MPa (87 ksi) — stronger than 60% of stainless steel grades. Strength varies by condition: see the 3 listed tempers.
Is ER309Cb-AW easy to machine?
Not especially — machinability is rated poor (32/100, worse than 62% of stainless steel grades). Overlay machines like Type 309/347: low speed, heavy positive-rake carbide, rigid setup and flood coolant to fight work hardening and gumming.
Can ER309Cb-AW be welded?
Yes — weldability is rated excellent (88/100). Run GTAW/GMAW/SAW with Ar or Ar+2%CO2 (or 100% Ar + He for TIG), interpass ≤150 °C and limited heat input to hold ferrite and avoid hot cracking; ideal buffer layer under 347/321 or before nickel-alloy cover passes.
What surface finishes work on ER309Cb-AW?
Grind, pickle and passivate the overlay to restore the passive film; avoid carbon-steel tooling contamination, no anodizing applies.
Can ER309Cb-AW be formed, bent or molded?
Supplied as cold-drawn wire; bend TIG rods only gently — the deposit itself work-hardens rapidly and is normally not cold formed.
What is the maximum service temperature of ER309Cb-AW?
ER309Cb-AW is rated for continuous use to about 800°C (1,472 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between ER309Cb-AW and ER309Cb AW-SAW?
AW is the default condition — standard condition for classification testing and most overlay/dissimilar-joint service — use unless PWHT is imposed by the base metal. AW-SAW: pick for high-deposition SAW wire or strip cladding of pressure-vessel steel; higher heat input gives slightly lower strength and toughness scatter. Yield strength is 410 MPa in AW versus 385 MPa in AW-SAW.
Sources
- AWS A5.9/A5.9M — Bare Stainless Steel Welding Electrodes and Rods — American Welding Society (2017)
- ASM Handbook Vol. 6 — Welding, Brazing and Soldering — ASM International (1993)
- ASM Handbook Vol. 1 — Properties and Selection: Irons, Steels — ASM International (1990)
- Stainless filler metal datasheets (309/309LNb class) — Böhler Welding / Sandvik / ESAB (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.