Electrode comparison

E309L vs E316L

E309L is for dissimilar joints and overlays; E316L is for matching 316 base metal in chloride service. They solve unrelated problems.

E309L vs E316L at a glance

	E309L	E316L
AWS specification	AWS A5.4/A5.4M	AWS A5.4/A5.4M
Process	Stick (SMAW)	Stick (SMAW)
Form	Covered electrode	Covered electrode
Tensile strength (min)	75 ksi	70 ksi
Yield strength (min)	45 ksi	40 ksi
Elongation (min)	30%	30%
Impact toughness	Not required by the specification	Not required; austenitic deposits remain tough at low temperature
Polarity	DCEP, AC	DCEP, AC
Positions	Flat, Horizontal, Vertical, Overhead	Flat, Horizontal, Vertical, Overhead
Penetration	Shallow to medium	Shallow to medium
Deposition rate	Medium	Medium
Coating / core	Lime-titania (-16)	Lime-titania (-16)
Slag	Self-lifting, must be fully removed between passes	Self-lifting, remove completely between passes
Shielding gas	None — self-shielding	None — self-shielding
Storage	Dry storage, rod oven after opening — same discipline as E308L.	Dry storage; rod oven at 250–300 °F (120–150 °C) after opening.
Primary use	Joining austenitic stainless to carbon or low-alloy steel	Marine and offshore stainless fabrication

Which should you use?

These two are rarely alternatives for the same joint. E309L's job is to survive dilution: its 23Cr-12Ni chemistry is deliberately rich so that mixing with carbon steel still leaves a sound austenitic-ferritic deposit. E316L's job is corrosion resistance: its 2 to 3% molybdenum fights pitting in chlorides. If you are joining 316 to carbon steel, you need dilution tolerance first, so E309L (or E309LMo where the specification calls for it) is the usual answer, not E316L.

Choose E309L when

Stainless to carbon steel joints
First layer of a clad overlay
Unknown or hard-to-weld base metals

Choose E316L when

Matching 316 or 316L base metal
Chloride and marine service
Chemical and pharmaceutical process work

Amperage compared

Diameter	E309L	E316L
3/32 in (2.4 mm)	40–80 A	40–80 A
1/8 in (3.2 mm)	65–110 A	65–110 A
5/32 in (4.0 mm)	95–150 A	95–150 A
3/16 in (4.8 mm)	130–190 A	130–190 A

Ranges are typical starting points. Diameters listed for only one electrode are shown as — for the other.

E309L vs E316L — common questions

What do you use to weld 316 stainless to carbon steel?

E309L is the common answer, with E309LMo specified where molybdenum must be carried through the transition weld. E316L alone would dilute into a crack-sensitive composition.

Does E309L resist chlorides like E316L?

Not in the same way. E309L has higher chromium but no molybdenum, so it does not match E316L's pitting resistance in chloride service.

Can E309L be used as a general stainless filler?

It will weld most austenitic grades soundly, which is why it is a popular repair rod for unknown steels. For matching work it costs more than the correct filler without adding anything.

Full specifications

E309L

AWS A5.4/A5.4M

E309L is the dissimilar-metal electrode — its extra chromium and nickel survive dilution when joining stainless to carbon steel or laying a stainless overlay.

E316L