AWS A5.9/A5.9M · Stainless Steel
ER316L Welding Electrode
ER316L is the molybdenum-bearing bare filler for 316 and 316L stainless — the standard TIG rod and MIG wire for marine, chemical and sanitary service.
- 70 ksi tensile
- Polarity DCEP (GMAW), DCEN (GTAW)
- 4 positions
- Medium penetration
- TIG (GTAW) / MIG (GMAW)
What ER316L means
| Part | Meaning |
|---|---|
| ER | Electrode or rod — usable for MIG or TIG |
| 316 | Nominal 18–20% chromium, 11–14% nickel, 2–3% molybdenum |
| L | Low carbon, 0.03% maximum |
ER316L specifications
| AWS specification | AWS A5.9/A5.9M |
|---|---|
| Process | TIG (GTAW) / MIG (GMAW) |
| Form | Solid wire / rod |
| Polarity | DCEP (GMAW), DCEN (GTAW) |
| Welding positions | Flat, Horizontal, Vertical, Overhead |
| Tensile strength (min) | 70 ksi (485 MPa) |
| Yield strength (min) | 40 ksi (275 MPa) |
| Elongation (min) | 30% |
| Impact toughness | Not required; austenitic deposits remain tough at low temperature |
| Coating / core | None — bare wire or rod |
| Penetration | Medium |
| Deposition rate | Medium to high depending on process |
| Slag | None; light oxide film to be cleaned or pickled |
| Arc character | Stable with a fluid puddle |
| Shielding gas | 100% argon for TIG; tri-mix or 98/2 for MIG |
ER316L 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 |
|---|---|---|
| 0.030 in (0.8 mm) MIG | 50–150 A | 100 A |
| 0.035 in (0.9 mm) MIG | 70–180 A | 125 A |
| 0.045 in (1.2 mm) MIG | 100–250 A | 175 A |
| 1/16 in (1.6 mm) TIG | 40–90 A | 65 A |
| 3/32 in (2.4 mm) TIG | 70–130 A | 100 A |
| 1/8 in (3.2 mm) TIG | 100–180 A | 140 A |
Polarity: MIG DCEP, TIG DCEN.
Shielding gas for ER316L
| Gas | Notes |
|---|---|
| 100% argon | Standard for TIG and pulsed MIG on stainless. |
| 90% He / 7.5% Ar / 2.5% CO2 | Tri-mix for short-circuit MIG. |
| 98% Ar / 2% CO2 | Spray transfer; keep CO2 low so weld carbon stays down. |
| Ar / 2% O2 | Spray transfer with good arc stability and wetting. |
Flow rate: 15–20 CFH for TIG, 25–35 CFH for MIG; argon back purge on pipe roots
What ER316L is used for
- Marine and offshore piping and structures
- Chemical, pulp-and-paper and pharmaceutical process equipment
- Sanitary tubing where chloride cleaning agents are used
- Heat exchangers and condensers in brackish service
- Any 316 joint where flux-free welds are required
Base metals
- Type 316 and 316L
- Type 317 where matching is not required
- Molybdenum-bearing austenitic grades
- Duplex-adjacent applications only where the WPS allows
Characteristics
- 2–3% molybdenum sharply improves pitting and crevice corrosion resistance in chlorides
- Low carbon protects the heat-affected zone from sensitization
- Typical ferrite in the FN 3–8 range, enough to resist hot cracking
- Better elevated-temperature creep strength than the 308 chemistry
- More expensive than ER308L — specify it when chlorides or the base metal demand it
Storage and handling
Clean, dry and isolated from iron contamination.
- Sealed tubes for TIG rod; desiccant-bagged spools for MIG.
- Use clean gloves; wipe with acetone if handled bare-handed.
- Never rest stainless filler on carbon steel surfaces or brush it with a carbon steel brush.
Welding tips
- Back purge pipe roots with argon — sugaring destroys the corrosion resistance you are paying for.
- Keep interpass temperature under 350 °F (175 °C) and run stringers.
- Pickle and passivate after welding on critical corrosion service; brushing alone leaves a chromium-depleted surface.
- Do not substitute ER308L on 316 base metal — the missing molybdenum shows up as pitting in service, not as a weld defect.
ER316L frequently asked questions
What is the difference between ER316L and ER308L?
ER316L contains 2–3% molybdenum for chloride and pitting resistance; ER308L has none. Use ER316L on 316/316L and in marine or chemical service, ER308L on 304/304L.
What gas do you use with ER316L?
100% argon for TIG. For MIG, a helium tri-mix for short circuit or 98% argon / 2% CO2 for spray. Keep CO2 low so the weld does not pick up carbon.
What amperage for 3/32 in ER316L TIG rod?
Roughly 70–130 A DCEN, with about 70–90 A on 1/8 in material and up toward 130 A on 1/4 in.
Does ER316L need to be back purged?
On pipe and tube roots, yes. Oxidation on the unshielded side forms sugaring, a rough gray scale that cannot be repaired without cutting the joint out.
Is ER316L suitable for saltwater?
It resists chlorides far better than 304-grade fillers, which is why it is standard for marine work, but it is not immune. For severe seawater service, specifiers move to duplex, super-austenitic or nickel alloys.
Compare ER316L with
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