Stainless Steel E309Nb-AW (As-welded deposit)
Heat-treated state · default condition
UNS W30917
Default condition for dissimilar-metal joints and buffer layers; use as-deposited unless the base metal demands PWHT.
Values for the AW condition
Other E309Nb tempers and conditions
E309Nb is listed in 2 conditions; see the grade overview at E309Nb.
- PWHT
- AW
Compare all 2 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Post-weld heat treated | Condition after the joint is stress-relieved with the ferritic base metal; Nb stabilization keeps the deposit sensitization-free but ferrite may partly transform, lowering toughness. | 400 | 590 | 32 | 11 HRC | 2.3 % IACS |
AWDefaultThis page As-welded deposit | Default condition for dissimilar-metal joints and buffer layers; use as-deposited unless the base metal demands PWHT. | 420 | 600 | 35 | 12 HRC | 2.2 % IACS |
What is E309Nb-AW?
E309Nb-AW is E309Nb heat treated to AW — default condition for dissimilar-metal joints and buffer layers; use as-deposited unless the base metal demands PWHT. E309Nb-AW has a yield strength of 420 MPa (60.9 ksi) and a tensile strength of 600 MPa (87 ksi) — stronger than 64% of stainless steel grades. Elongation at break is 35% and the elastic modulus is 196 GPa (28.4 Msi). E309Nb-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 — 85/100, better than 87% of stainless steel grades
Limitations
- Hard to polish — 55/100, worse than 89% of stainless steel grades
- High embodied carbon — 5.5 kg CO₂/kg, worse than 77% of stainless steel grades
E309Nb-AW properties
Typical room-temperature values for E309Nb-AW; 24 are specific to this condition. Other listed values are E309Nb reference data and may not represent this condition. Bars are the position among stainless steel grades.
Physical3
E309Nb-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).
Mechanical17
E309Nb-AW has a yield strength of 420 MPa (60.9 ksi) and a tensile strength of 600 MPa (87 ksi) — stronger than 64% of stainless steel grades. Elongation at break is 35% and the elastic modulus is 196 GPa (28.4 Msi).
Thermal6
E309Nb-AW is rated for continuous service to 425°C (797 °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
E309Nb-AW conducts electricity at 2.2 % IACS, worse than 61% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is good (65/100), better than 56% of stainless steel grades.
Sustainability4
Producing a kilogram of E309Nb-AW takes about 70 MJ of energy and emits 5.5 kg of CO₂ — more than 81% of stainless steel grades. Typical recycled content is 60%.
Manufacturability5
E309Nb-AW's machinability is poor (30/100, worse than 70% of stainless steel grades); weldability excellent (85/100); formability fair (40/100).
Common Calculations5
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with E309Nb-AW
Is E309Nb easy to machine?
Deposit machines like an austenitic stainless with hard ferrite/NbC particles — use sharp carbide, positive rake, low speed, heavy feed and flood coolant to avoid work hardening.
Can E309Nb be welded?
Use short arc, low heat input and stringer beads; DCEP (AC also for -16/-17/-26), interpass below ~150 °C, and redry electrodes per the maker (typically 250–300 °C for basic types) before use.
Can E309Nb be formed, bent or molded?
Not a wrought product; deposit is ductile enough for weld dressing and light peening but should not be cold-formed as a structural section.
What surface finishes work on E309Nb?
Pickle and passivate or mechanically clean the slag/heat tint; the ferrite makes the bead magnetically detectable and slightly harder to polish to a mirror finish than fully austenitic deposits.
E309Nb 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 A5.4 undiluted weld metal | ≤ 0.12 | 0.06 |
| Cr | 22 – 25 | 23.5 |
| Ni | 12 – 14 | 13 |
| NbNb+Ta (Cb+Ta), stabilizer | 0.7 – 1 | 0.85 |
| Mn | 0.5 – 2.5 | 1.5 |
| Si | ≤ 0.9 | 0.6 |
| Moresidual | ≤ 0.75 | 0.15 |
| Curesidual | ≤ 0.75 | 0.1 |
| P | ≤ 0.04 | 0.02 |
| S | ≤ 0.03 | 0.01 |
| Fe | balance | — |
E309Nb-AW — frequently asked
What is E309Nb-AW used for?
E309Nb-AW is typically used for dissimilar metal welding, carbon-to-stainless transition joints, cladding/overlay on carbon steel and buffer layers before stainless overlay. In short: nb-stabilized dissimilar-metal electrode; standard buffer-layer filler; resists carbide precipitation.
What is the yield strength of E309Nb-AW?
E309Nb-AW has a typical yield strength of 420 MPa (60.9 ksi) and a tensile strength of 600 MPa (87 ksi) — stronger than 64% of stainless steel grades. Strength varies by condition: see the 2 listed tempers.
Is E309Nb-AW easy to machine?
Not especially — machinability is rated poor (30/100, worse than 70% of stainless steel grades). Deposit machines like an austenitic stainless with hard ferrite/NbC particles — use sharp carbide, positive rake, low speed, heavy feed and flood coolant to avoid work hardening.
Can E309Nb-AW be welded?
Yes — weldability is rated excellent (85/100). Use short arc, low heat input and stringer beads; DCEP (AC also for -16/-17/-26), interpass below ~150 °C, and redry electrodes per the maker (typically 250–300 °C for basic types) before use.
What surface finishes work on E309Nb-AW?
Pickle and passivate or mechanically clean the slag/heat tint; the ferrite makes the bead magnetically detectable and slightly harder to polish to a mirror finish than fully austenitic deposits.
Can E309Nb-AW be formed, bent or molded?
Not a wrought product; deposit is ductile enough for weld dressing and light peening but should not be cold-formed as a structural section.
What is the maximum service temperature of E309Nb-AW?
E309Nb-AW is rated for continuous use to about 425°C (797 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between E309Nb-AW and E309Nb PWHT?
AW is the default condition — default condition for dissimilar-metal joints and buffer layers; use as-deposited unless the base metal demands PWHT. PWHT: condition after the joint is stress-relieved with the ferritic base metal; Nb stabilization keeps the deposit sensitization-free but ferrite may partly transform, lowering toughness. Yield strength is 420 MPa in AW versus 400 MPa in PWHT.
Sources
- AWS A5.4/A5.4M — Specification for Stainless Steel Electrodes for Shielded Metal Arc Welding — American Welding Society (2012)
- ASME BPVC Section II Part C — SFA-5.4 — ASME (2023)
- ASM Handbook Vol. 6 — Welding, Brazing and Soldering — ASM International (1993)
- ASM Handbook Vol. 1 — Properties and Selection: Irons, Steels and High-Performance Alloys — ASM International (1990)
- Stainless SMAW electrode datasheets (309Nb/309Cb types) — 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.