Electrode and wire designations explained
Type the designation off the box — E7018, ER70S-6, E 42 5 B 42 H5 — and it gets pulled apart field by field, with each one explained. Below are the full code tables to EN ISO and AWS.
Try a ready one:
Works for covered electrodes and for wires, in both the European and the American notation. EN ISO designations are written with spaces, American ones run together.
Covered electrodes to EN ISO 2560
Read it left to right: the type letter, strength, impact toughness, chemistry, covering, deposition yield with the current, positions and hydrogen at the end. The first two figures are the ones that matter — they say which steel the electrode belongs to.
E 42 5 B 42 H5
| Code | Yield strength | Tensile strength Rm |
|---|---|---|
| 35 | 355 MPa | 440–570 MPa |
| 38 | 380 MPa | 470–600 MPa |
| 42 | 420 MPa | 500–640 MPa |
| 46 | 460 MPa | 530–680 MPa |
| 50 | 500 MPa | 560–720 MPa |
| Code | Impact 47 J at |
|---|---|
| Z | not required |
| A | +20 °C |
| 0 | 0 °C |
| 2 | −20 °C |
| 3 | −30 °C |
| 4 | −40 °C |
| 5 | −50 °C |
| 6 | −60 °C |
| Code | Covering |
|---|---|
| A | acid |
| C | cellulosic |
| R | rutile |
| RR | thick rutile |
| RC | rutile-cellulosic |
| RA | rutile-acid |
| RB | rutile-basic |
| B | basic |
| Code | Deposition yield | Current |
|---|---|---|
| 1 | ≤ 105 % | AC and DC |
| 2 | ≤ 105 % | DC only |
| 3 | 105–125 % | AC and DC |
| 4 | 105–125 % | DC only |
| 5 | 125–160 % | AC and DC |
| 6 | 125–160 % | DC only |
| 7 | > 160 % | AC and DC |
| 8 | > 160 % | DC only |
| Code | Welding positions |
|---|---|
| 1 | all positions |
| 2 | all except vertical down |
| 3 | flat and horizontal fillet |
| 4 | flat only |
| 5 | as 3 plus vertical down |
| Code | Hydrogen, ml/100 g |
|---|---|
| H5 | ≤ 5 ml/100 g |
| H10 | ≤ 10 ml/100 g |
| H15 | ≤ 15 ml/100 g |
Covered electrodes to AWS A5.1
Four digits after the letter E: the first two are the tensile strength in thousands of pounds per square inch, the third is the positions, the fourth is the covering together with the current. That is why E7018 and E6013 differ in more than strength.
E 70 1 8
| Code | Tensile strength Rm | |
|---|---|---|
| 60 | 430 MPa | 60 ksi |
| 70 | 490 MPa | 70 ksi |
| 80 | 550 MPa | 80 ksi |
| Code | Welding positions |
|---|---|
| 1 | all positions |
| 2 | flat and horizontal |
| 4 | all, including vertical down |
| Code | Covering | Current |
|---|---|---|
| 0 | cellulosic sodium | DC+ |
| 1 | cellulosic potassium | AC / DC+ |
| 2 | rutile sodium | AC / DC− |
| 3 | rutile potassium | AC / DC± |
| 4 | rutile with iron powder | AC / DC± |
| 5 | basic sodium | DC+ |
| 6 | basic potassium | AC / DC+ |
| 7 | oxide with iron powder | AC / DC± |
| 8 | basic with iron powder | AC / DC± |
Solid wire: EN ISO 14341 and AWS A5.18
In the European notation the letter G is followed by strength, toughness, shielding gas and wire chemistry. The American ER70S-6 says the same thing more briefly: 70 ksi, solid wire, chemistry number six.
G 42 3 M21 3Si1 ER 70 S -6
| Code | Wire composition |
|---|---|
| 2Si | low silicon |
| 3Si1 | the standard one, silicon and manganese |
| 4Si1 | more silicon, a runnier pool |
| 2Ti | with titanium, for rusty plate |
| 3Ni1 | with nickel, toughness below zero |
| 2Mo | with molybdenum, creep resistant |
| Code | Shielding gas | Where it is used |
|---|---|---|
| I1 | Ar 100 % | TIG, MIG |
| M12 | Ar + 0,5–5 % CO₂ | 141 / 135 |
| M21 | Ar + 15–25 % CO₂ | 135 / 136 |
| C1 | CO₂ 100 % | 135 / 136 |
| Code | Wire composition |
|---|---|
| 2 | titanium and zirconium, for rusty plate |
| 3 | low silicon, less spatter |
| 4 | more manganese and silicon |
| 6 | highest silicon and manganese, the all-rounder |
| G | composition agreed with the maker |
Flux-cored wire and stainless electrodes
On flux-cored wire the letter T is followed by the core type — that decides whether the bead comes out smooth and how little hydrogen stays in the weld. On stainless electrodes the two digits after the dash are the covering and the current.
| Code | What it means |
|---|---|
| T-1 | rutile core, a smooth bead |
| T-5 | basic core, low hydrogen |
| T-4 | metal core, little slag |
| 15 | basic, DC only |
| 16 | rutile, AC and DC |
| 17 | rutile-silicate |
What the designation will not tell you
The code describes the deposited metal, not your joint. It holds no plate thickness, no preheat, and no record of whether the electrode was baked. A dry basic electrode and the same one after a night in a damp shop are two different consumables under one designation.
Frequently asked questions
What does E7018 mean?
Seventy ksi of tensile strength, about 490 MPa; the one means all welding positions; the eight means a basic covering with iron powder, on AC and DC. It is the everyday low-hydrogen electrode for structural work.
How does E6013 differ from E7018?
E6013 has a rutile covering: it strikes easily and forgives dirt and an uneven gap, but its impact toughness is lower. E7018 is basic and low-hydrogen — harder to run, yet the weld resists cracking. For load-bearing joints you take E7018.
What does H5 at the end of the designation mean?
Diffusible hydrogen in the deposited metal: no more than 5 ml per 100 g. The less hydrogen, the lower the risk of cold cracks. The figure only holds for a dry electrode — after a night in a damp shop it means nothing at all.
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