Stainless Steel E309Nb
UNS W30917
E309Nb (W30917) is a niobium-stabilized 309-type covered electrode whose Nb addition suppresses carbide precipitation in the deposit.
Reference datasheet — E309Nb is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the AW condition
E309Nb tempers and conditions
E309Nb is supplied in 2 conditions, soft to hard. AW is the default FabDigit quotes; the values on this page are for it.
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 |
AWDefault 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 |
Supply forms, finishes and certifications
Ways E309Nb is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
E309Nb-15 | Basic (lime) coating, DCEP only | Supply option |
E309Nb-16 | Rutile (titania) coating, AC or DCEP | Supply option |
E309Nb-17 | Rutile-silica coating, AC or DCEP | Supply option |
E309Nb-25 | Heavy basic coating, flat/horizontal fillet, DCEP | Supply option |
E309Nb-26 | Heavy rutile coating, flat/horizontal fillet, AC or DCEP | Supply option |
What is E309Nb?
E309Nb (W30917) is a niobium-stabilized 309-type covered electrode whose Nb addition suppresses carbide precipitation in the deposit. It is used for dissimilar-metal joints, carbon-to-stainless transition welds and as a buffer layer beneath stainless overlay, and is supplied in -15, -16, -17, -25 and -26 coating types. As-welded deposit properties are about 420 MPa yield, 600 MPa tensile, 35 % elongation and 190 HB (90 HRB), with service to 425 °C. The deposit is ferrite-containing and therefore magnetic; where a fully austenitic, non-magnetic buffer is required, use a 309L or nickel-base filler instead. E309Nb 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). E309Nb 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).
What is E309Nb used for?
- dissimilar metal welding
- carbon-to-stainless transition joints
- cladding/overlay on carbon steel
- buffer layers before stainless overlay
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 properties
Typical room-temperature values for E309Nb-AW; bars are the position among stainless steel grades.
Physical3
E309Nb 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 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 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 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 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'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. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the stainless steel family
Yield strength against density for every stainless steel grade FabDigit runs. E309Nb is highlighted; hover a dot for its name, or open the interactive family chart.
Working with E309Nb
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.
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 |
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.
Surface treatments FabDigit runs on stainless steel parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
Passivation
Organic Coating
Thermal Spray
Equivalent designations
Standards and trade names that resolve to Stainless Steel E309Nb in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- W30917
- Also called
- AWS A5.4 E309NbE309Cb
How much does E309Nb cost?
E309Nb is a high-cost stainless steel ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
E309Nb — frequently asked
What is E309Nb used for?
E309Nb 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?
E309Nb 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 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 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?
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 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?
E309Nb 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.
How much does E309Nb cost?
E309Nb is a high-cost stainless steel ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
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; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.