Stainless Steel ER309-AW (As-welded deposit)
Heat-treated state · default condition
UNS S30980 · EN 23 12
Standard reference condition: undiluted all-weld-metal tested as deposited, no post-weld heat treatment.
Values for the AW condition
Other ER309 tempers and conditions
ER309 is listed in 5 conditions; see the grade overview at ER309.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Post-weld heat treated | Use when the fabrication is solution annealed after welding: ferrite is partly dissolved, strength drops and ductility/corrosion resistance recover. | 300 | 550 | 45 | 160 HB | 2.2 % IACS |
AW | High-deposition strip/wire cladding and heavy-section joints; properties depend strongly on flux, dilution runs higher. | 380 | 580 | 35 | 180 HB | 2.2 % IACS |
AW | Cut-length TIG rod deposit; cleanest, lowest-oxygen weld metal with the best toughness — pick for root passes and thin sections. | 390 | 590 | 40 | 175 HB | 2.2 % IACS |
AWDefaultThis page As-welded deposit | Standard reference condition: undiluted all-weld-metal tested as deposited, no post-weld heat treatment. | 400 | 600 | 38 | 180 HB | 2.2 % IACS |
AW | Spooled solid wire deposit for semi-automatic/robotic overlay; slightly higher strength and lower toughness than TIG because of oxidising shielding gas. | 410 | 610 | 36 | 185 HB | 2.2 % IACS |
What is ER309-AW?
ER309-AW is ER309 heat treated to AW — standard reference condition: undiluted all-weld-metal tested as deposited, no post-weld heat treatment. ER309-AW has a yield strength of 400 MPa (58 ksi) and a tensile strength of 600 MPa (87 ksi) — stronger than 57% of stainless steel grades. Elongation at break is 38% and the elastic modulus is 196 GPa (28.4 Msi). ER309-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 — 92/100, better than 98% of stainless steel grades
- High service temperature — 1,000°C (1,832 °F), better than 88% of stainless steel grades
ER309-AW properties
Typical room-temperature values for ER309-AW; 23 are specific to this condition. Other listed values are ER309 reference data and may not represent this condition. Bars are the position among stainless steel grades.
Physical3
ER309-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
ER309-AW has a yield strength of 400 MPa (58 ksi) and a tensile strength of 600 MPa (87 ksi) — stronger than 57% of stainless steel grades. Elongation at break is 38% and the elastic modulus is 196 GPa (28.4 Msi).
Thermal6
ER309-AW is rated for continuous service to 1,000°C (1,832 °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
ER309-AW conducts electricity at 2.2 % IACS, worse than 61% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is very good (72/100), better than 73% of stainless steel grades.
Sustainability4
Producing a kilogram of ER309-AW takes about 62 MJ of energy and emits 5.2 kg of CO₂ — more than 75% of stainless steel grades. Typical recycled content is 60%.
Manufacturability7
ER309-AW's machinability is poor (34/100, worse than 55% of stainless steel grades); weldability excellent (92/100); formability good (60/100).
Common Calculations5
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with ER309-AW
Is ER309 easy to machine?
Machining applies to the deposit/overlay: austenitic, gummy and work-hardening — rigid setup, sharp positive-rake carbide, heavy feed, flood coolant, no dwelling.
Can ER309 be welded?
Run with DCEN (GTAW) or DCEP (GMAW), Ar or Ar+2%O₂/Ar-He, low heat input and interpass ≤150 °C; aim for 8–15 FN ferrite to avoid hot cracking in dilute dissimilar joints.
Can ER309 be formed, bent or molded?
Supplied as cold-drawn wire; keep spool cast/helix within spec and use U-groove or knurl-free drive rolls plus a low-friction liner to prevent birdnesting.
What surface finishes work on ER309?
Pickle and passivate or mechanically blend the bead; do not anodise — grinding debris from carbon steel must be removed to avoid rust staining on the overlay.
ER309 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 |
|---|---|---|
| Cnon-L grade; ER309L is ≤0.03 | ≤ 0.12 | 0.08 |
| Cr | 23 – 25 | 24 |
| Ni | 12 – 14 | 13 |
| Mn | 1 – 2.5 | 1.8 |
| SiER309Si raises Si to 0.65–1.00 | 0.3 – 0.65 | 0.45 |
| Moresidual | ≤ 0.75 | — |
| Curesidual | ≤ 0.75 | — |
| P | ≤ 0.03 | — |
| S | ≤ 0.03 | — |
| Fe | balance | — |
ER309-AW — frequently asked
What is ER309-AW used for?
ER309-AW is typically used for dissimilar joints between carbon steel and stainless steel, buffer layers under stainless or nickel-alloy overlay, weld overlay cladding of carbon steel vessels, stainless-clad plate seam and edge welds, transition joints in piping systems and repair welds on 309-type heat-resisting fabrications. In short: standard dissimilar-metal filler; tolerates high carbon-steel dilution; service to 1000 °C.
What is the yield strength of ER309-AW?
ER309-AW has a typical yield strength of 400 MPa (58 ksi) and a tensile strength of 600 MPa (87 ksi) — stronger than 57% of stainless steel grades. Strength varies by condition: see the 5 listed tempers.
Is ER309-AW easy to machine?
Not especially — machinability is rated poor (34/100, worse than 55% of stainless steel grades). Machining applies to the deposit/overlay: austenitic, gummy and work-hardening — rigid setup, sharp positive-rake carbide, heavy feed, flood coolant, no dwelling.
Can ER309-AW be welded?
Yes — weldability is rated excellent (92/100). Run with DCEN (GTAW) or DCEP (GMAW), Ar or Ar+2%O₂/Ar-He, low heat input and interpass ≤150 °C; aim for 8–15 FN ferrite to avoid hot cracking in dilute dissimilar joints.
What surface finishes work on ER309-AW?
Pickle and passivate or mechanically blend the bead; do not anodise — grinding debris from carbon steel must be removed to avoid rust staining on the overlay.
Can ER309-AW be formed, bent or molded?
Supplied as cold-drawn wire; keep spool cast/helix within spec and use U-groove or knurl-free drive rolls plus a low-friction liner to prevent birdnesting.
What is the maximum service temperature of ER309-AW?
ER309-AW is rated for continuous use to about 1,000°C (1,832 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between ER309-AW and ER309 PWHT?
AW is the default condition — standard reference condition: undiluted all-weld-metal tested as deposited, no post-weld heat treatment. PWHT: use when the fabrication is solution annealed after welding: ferrite is partly dissolved, strength drops and ductility/corrosion resistance recover. Yield strength is 400 MPa in AW versus 300 MPa in PWHT.
Sources
- AWS A5.9/A5.9M — Bare Stainless Steel Welding Electrodes and Rods — AWS (2017)
- ASM Handbook Vol.6 — Welding, Brazing and Soldering — ASM International (1993)
- ASM Specialty Handbook — Stainless Steels — ASM International (1994)
- ER309 / 309Si solid wire datasheets — Böhler Welding / ESAB / Lincoln Electric (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.