AWS A5.4/A5.4M · Stainless Steel
E309L Welding Electrode
E309L is the dissimilar-metal electrode — its extra chromium and nickel survive dilution when joining stainless to carbon steel or laying a stainless overlay.
- 75 ksi tensile
- Polarity DCEP, AC
- 4 positions
- Shallow to medium penetration
- Stick (SMAW)
What E309L means
| Part | Meaning |
|---|---|
| E | Covered electrode for shielded metal arc welding |
| 309 | Nominal 23% chromium, 12% nickel — deliberately over-alloyed relative to 304 |
| L | Low carbon, 0.04% maximum |
| -16 | Lime-titania coating usable on AC or DCEP |
E309L specifications
| AWS specification | AWS A5.4/A5.4M |
|---|---|
| Process | Stick (SMAW) |
| Form | Covered electrode |
| Polarity | DCEP, AC |
| Welding positions | Flat, Horizontal, Vertical, Overhead |
| Tensile strength (min) | 75 ksi (520 MPa) |
| Yield strength (min) | 45 ksi (310 MPa) |
| Elongation (min) | 30% |
| Impact toughness | Not required by the specification |
| Coating / core | Lime-titania (-16) |
| Penetration | Shallow to medium |
| Deposition rate | Medium |
| Slag | Self-lifting, must be fully removed between passes |
| Arc character | Smooth, fluid puddle |
| Shielding gas | None — self-shielding |
E309L amperage by diameter
Typical operating ranges. Start near the middle of the range, then adjust by sound and bead profile. Reduce 10–15% for vertical and overhead work.
| Diameter | Amperage range | Typical start |
|---|---|---|
| 3/32 in (2.4 mm) | 40–80 A | 60 A |
| 1/8 in (3.2 mm) | 65–110 A | 88 A |
| 5/32 in (4.0 mm) | 95–150 A | 122 A |
| 3/16 in (4.8 mm) | 130–190 A | 160 A |
Polarity: DCEP standard; the -16 coating also runs on AC.
What E309L is used for
- Joining austenitic stainless to carbon or low-alloy steel
- First-layer buffer on carbon steel before a stainless overlay
- Cladding and weld overlay on pressure vessels
- Welding 309 and 309S heat-resistant base metals
- Repair welds on unknown or difficult-to-weld steels
Base metals
- 304/304L to carbon steel
- Type 309 and 309S
- Buffer layers on carbon steel before 308L or 316L overlay
- Hard-to-weld and unknown steels
Characteristics
- Over-alloyed on purpose: after roughly 30% dilution from carbon steel, the deposit still lands in a safe austenitic-ferritic range
- Retains delta ferrite after dilution, which is what prevents hot cracking
- Serves as a general-purpose repair filler for unknown steels because of its tolerance for dilution
- Higher chromium also gives good oxidation resistance to about 1900 °F (1040 °C)
- More expensive than E308L, so it is used where the dilution or service demands it
Storage and handling
Dry storage, rod oven after opening — same discipline as E308L.
- Hold at 250–300 °F (120–150 °C) once the container is opened.
- Redry damp rods per the manufacturer's data sheet, typically 500–600 °F (260–315 °C) for one hour.
- Keep away from carbon steel consumables to avoid iron contamination.
Welding tips
- On a stainless-to-carbon joint, aim the arc slightly toward the carbon steel side only if the WPS calls for it; otherwise center it and keep dilution low.
- For overlay work, one buffer layer of E309L then subsequent layers of E308L or E316L is the standard sequence.
- Keep amperage at the low end and use stringer beads to minimize dilution.
- Interpass temperature below 350 °F (175 °C) as with all austenitic deposits.
E309L frequently asked questions
What is E309L used for?
Welding stainless steel to carbon steel, laying the first buffer layer of a stainless overlay, welding 309 base metal, and repairing unknown or hard-to-weld steels.
Why use E309L instead of E308L for dissimilar joints?
Melting carbon steel into the puddle dilutes the alloy content. E309L starts with about 23% chromium and 12% nickel, so after dilution it still contains enough ferrite to resist hot cracking. An E308L deposit diluted the same way turns martensitic and cracks.
What amperage for 1/8 in E309L?
65–110 A DCEP, commonly 80–95 A. Use the low end and stringer beads to keep dilution down.
Can E309L weld 304 to 304?
Yes, it will make a sound and corrosion-resistant weld, but it costs more than E308L and offers no advantage on a matching joint.
Is E309L magnetic?
Slightly. The deposit contains delta ferrite, which is ferromagnetic, so a magnet will show weak attraction. That is expected and is what keeps the weld from hot cracking.
Compare E309L with
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