Table: welding current, electrode diameter and plate thickness
One table for stick welding: from the thickness of the part to the electrode diameter and the current range in every position. Figures are for rutile electrodes on low-carbon steel.
The main table
| Material thickness, mm | Electrode diameter, mm | Flat, A | Horizontal, A | Vertical, A | Overhead, A |
|---|---|---|---|---|---|
| 1–2 | 1.6 | 40–60 | 35–55 | 35–50 | 30–50 |
| 1.5–3 | 2.0 | 50–80 | 45–70 | 45–70 | 40–65 |
| 2–4 | 2.5 | 70–100 | 65–90 | 60–85 | 55–80 |
| 3–5 | 3.0 | 80–130 | 70–115 | 70–110 | 65–105 |
| 3–6 | 3.2 | 90–140 | 80–125 | 75–120 | 70–110 |
| 6–12 | 4.0 | 130–190 | 115–170 | 110–160 | 105–150 |
| 10–20 | 5.0 | 180–250 | 160–225 | — | — |
| 16 and over | 6.0 | 230–320 | 205–290 | — | — |
Electrodes of 5 and 6 mm are effectively never used vertically or overhead: the pool becomes too large to hold. In those positions the electrode goes no thicker than 4 mm and the joint is filled with several runs.
Correction for the coating
| Coating | Typical designations | Factor | Current |
|---|---|---|---|
| Rutile | OK 46.00, E 42 0 RC 11 | 1.00 | AC / DC± |
| Basic | OK 48.00, E 42 4 B 42 | 1.05 | DC+ only |
| Cellulosic | OK 22.45 | 0.95 | DC+ (downhill: DC−) |
| Acid | OK 43.32 | 1.00 | AC / DC |
Work it out for your case
The table gives a range; the current calculator applies the corrections for position and coating straight away and checks whether the diameter suits your thickness.
Frequently asked questions
How do I estimate the current without the table?
For 3 to 5 mm electrodes the rule of "30 to 40 amperes per millimetre of diameter" works: a 3 mm electrode is about 100 A, a 4 mm one about 150 A. For thin electrodes the factor is higher, for thick ones lower.
Is the electrode diameter chosen for the thickness or for the current?
For the thickness — that comes first. The diameter decides how much metal you can lay in one run; the current merely serves the diameter you picked. If the current will not fit inside the range, the electrode is the wrong one.
Updated: