2026-10-11 · min read
E6010, E6011 and E7018 are all covered carbon steel electrodes, all rated for all-position work, and they are still not interchangeable. The reason is the coating: two are cellulosic and one is a low-hydrogen basic coating. That one difference decides the polarity, the penetration, where the electrode can be used, and how it has to be stored.
Reading the designation
An AWS A5.1 covered electrode designation reads left to right. E means electrode. The next two or three digits give the minimum tensile strength of the deposited metal, in thousands of pounds per square inch: 60 means 60,000 psi (about 410 MPa) and 70 means 70,000 psi (about 480 MPa). The digit after that is the welding position, where 1 means all position and 2 means flat and horizontal fillet only. The last two digits together identify the coating type and the welding current the electrode is designed to run on, and an optional suffix letter marks an alloying element.
So E6010, E6011 and E7018 all carry the 1 for all position, and everything that matters sits in the final two digits.
Cellulosic versus low-hydrogen
E6010 and E6011 are cellulosic electrodes. The coating burns to produce a forceful, deeply penetrating arc with a fast-freezing slag, which is why they are the traditional choice for pipeline root passes and for vertical-down welding. The same characteristic means the arc burns through light rust and mill scale rather than riding over it.
E7018 takes the opposite approach. Its coating is basic and low in hydrogen, with a heavy iron powder content. Our E7018 is specified as a basic coated iron powder low potassium hydrogen type electrode, suitable for all-position welding on carbon and low-alloy steel structures such as Q345. It runs with little spatter and easy slag removal, and the iron powder raises deposition efficiency so fewer passes are needed for a given joint.
The hydrogen matters for a specific reason: hydrogen left in the weld is a leading cause of underbead cracking in restrained, thick or high-strength joints. A low-hydrogen coating exists to keep it out, and that protection only holds while the electrode is dry.
The three side by side
| E6010 | E6011 | E7018 | |
|---|---|---|---|
| Coating | Cellulosic | Cellulosic, potassium type | Basic, iron powder, low-hydrogen |
| Current and polarity | DCEP | AC or DCEP | AC or DCEP |
| Positions | All position | All position, including vertical-down | All position |
| Arc character | Forceful, deep penetration | Forceful, deep penetration | Smooth, moderate penetration |
| Hydrogen | Not low-hydrogen | Not low-hydrogen | Low-hydrogen |
| Typical use | Root passes, pipeline, vertical-down | Root passes; the same work where only AC is available | Structural steel, restrained and thick joints |
| Before use | Redry at 70-90 °C for 1 hour if damp | Redry at 70-90 °C for 1 hour if damp | Bake at 350-380 °C for 1 hour |
What our electrodes are required to meet
The figures below are the requirements our E6011 and E7018 are built and tested to. AWS A5.1 sets its own minimum for each classification; these are the values we hold the product to, and the typical results sit comfortably inside them.
| Deposited metal | E6011 | E7018 |
|---|---|---|
| Carbon | 0.20% max | 0.10% max |
| Manganese | 1.20% max | 0.85-1.40% |
| Silicon | 1.00% max | 0.65% max |
| Tensile strength | 430 MPa min | 490-660 MPa |
| Yield strength | 330 MPa min | 400 MPa min |
| Elongation | 20% min | 20% min |
| Charpy V-notch at -30 °C | 27 J min | 80 J min |
| Radiographic inspection | Grade II | Grade I |
The E7018 requirement of 80 J at -30 °C is our own specification and is the reason we list the grade where low-temperature toughness is called for. It is worth reading as a product specification rather than as a figure quoted from AWS A5.1, which does not require an impact value for a plain E7018.
Choosing between them
- Root passes on pipe, and any vertical-down work: E6010 or E6011, for the fast-freezing slag and the penetration.
- Only AC available on site: E6011 rather than E6010, since the potassium coating is what allows the electrode to run on alternating current.
- Structural, restrained or thick joints, where resistance to cracking is the priority: E7018.
- Flat and horizontal work where deposition rate and a clean finish matter: E7018, on the strength of its iron powder content.
- If baking electrodes at 350-380 °C before use is not practical on your site, a cellulosic electrode is the honest alternative rather than an E7018 that has been left to absorb moisture.
A note on the figures
The requirements above are published for the grades we hold them for. Where a figure is not published for a grade it has been left out rather than filled in from a general reference, so the tables here may show fewer rows for one electrode than another.