By plate thickness
| Plate thickness (mm) | Electrode Ø (mm) | Current (A) |
|---|---|---|
| up to 2 | 2.0 | 40–60 |
| 2–3 | 2.5 | 60–100 |
| 3–5 | 3.2 | 90–140 |
| 5–8 | 4.0 | 140–180 |
| 8–12 | 5.0 | 180–250 |
| over 12 | 5.0–6.0 | 180–290 |
A rule of thumb, not a standard: for thin plate you choose a thin electrode, and for thick plate a thick one with several passes; the root of the joint is usually welded with a thinner electrode (Ø 2.5–3.2 mm).
By electrode diameter
| Electrode Ø (mm) | Approximate current (A) | Suitable plate thickness (mm) |
|---|---|---|
| 2.0 | 40–60 | 1.5–2.5 |
| 2.5 | 60–100 | 2–4 |
| 3.2 | 90–140 | 3–6 |
| 4.0 | 140–180 | 5–10 |
| 5.0 | 180–250 | 8–12 and over (multi-pass) |
| 6.0 | 220–290 | over 10 (multi-pass) |
Indicative. Values are for rutile electrodes, flat position. In the vertical or overhead position, reduce the current by about 10–20 %. Basic electrodes (for example E7018) usually need drying as per the data sheet; rutile ones usually do not. Always follow the data on the packaging.
Signs that the current is wrong
- Too high: a lot of spatter, burnt edges, a wide flat bead, the electrode glows red.
- Too low: unstable arc, the electrode sticks, a narrow, rounded bead, poor penetration.
Frequently asked questions
What current do I use for a 3.2 mm electrode?
About 90–140 A for a rutile electrode, in the flat position. For plate of 3–6 mm.
What current do I use for a 2.5 mm electrode?
About 60–100 A, for plate of 2–4 mm. In the vertical position, less.
Which electrode do I choose for 4 mm plate?
Usually Ø 3.2 mm, at 90–140 A; for a single pass on thin plate you can also use Ø 2.5 mm.
How much electrode do I use?
It depends on the length of the weld and the thickness of the joint. Calculate the consumption in the welding consumption calculator.
Welding consumption calculator