Electrodes and Filler Metal Classification
E7018 designation system, electrode types, low-hydrogen storage, polarity, and filler metal selection.
- Decode the AWS electrode designation system using E7018 as the reference
- Explain low-hydrogen electrode storage requirements
- Distinguish between DCEP, DCEN, and AC polarity and their effects
Lesson 1
Electrode Designation System
Decoding E7018
The AWS electrode designation system packs critical information into a short code. Using E7018 as the example:
The "E" stands for Electrode. The first two digits (70) represent the minimum tensile strength in ksi (70,000 psi). The third digit (1) indicates welding positions - "1" means all positions (flat, horizontal, vertical, overhead), while "2" means flat and horizontal only. The last digit (8) indicates the coating type and current - "8" means low-hydrogen iron powder coating, usable on AC or DCEP.
Common Electrode Types
| Electrode | Type | Coating | Current | Use |
|---|---|---|---|---|
| E6010 | Cellulose | High cellulose sodium | DCEP only | Root passes, pipe, deep penetration |
| E6011 | Cellulose | High cellulose potassium | AC or DCEP | Similar to 6010, works on AC |
| E7018 | Low-hydrogen | Iron powder low-hydrogen | AC or DCEP | Structural, all-purpose |
| E7024 | Iron powder | Iron powder titania | AC or DCEP | Flat/horizontal only, high deposition |
Most Tested Electrode
E7018 is the most commonly tested electrode on the AWS exam. Know every digit: E = electrode, 70 = tensile strength in ksi, 1 = all positions, 8 = low-hydrogen iron powder with AC or DCEP.
In E7018: E = electrode, 70 = minimum tensile strength (70,000 psi), 1 = all positions, 8 = low-hydrogen iron powder coating on AC or DCEP. This designation system is the single most tested topic in electrode classification.