E7018 Low Hydrogen Stick Welding Electrode
Comprehensive technical specification for E7018 low hydrogen stick welding electrodes, covering properties, sizing, machinability, defects, and handling for Canadian fabrication and welding operations. AWS A5.1 / CSA W48 classified.
Material Overview & Common Uses
E7018 is a low hydrogen, iron powder, all-position stick electrode (SMAW) classified under AWS A5.1 / CSA W48. It is the most common electrode for structural steel fabrication in Canada, especially for code work (CWB, CSA S16, W59). The low hydrogen coating (max 0.4% diffusible hydrogen per 100g of deposited metal) minimizes cold cracking in restrained joints and high-carbon steels. Typical applications include: bridge and building structural welding, heavy equipment repair, pressure vessel fabrication, shipbuilding, and general shop fabrication on mild and medium-carbon steels. It is preferred for out-of-position welding (vertical up, overhead) due to its fast-freeze slag system. Common base metals include A36, A572 Gr50, A992, and 44W/50W Canadian grades.
Core Technical Properties & Sizing
| Parameter | Value | Notes |
|---|---|---|
| Tensile Strength | 490–590 MPa (71–86 ksi) | As-welded |
| Yield Strength | ≥ 400 MPa (58 ksi) | As-welded |
| Elongation (in 2″) | ≥ 22% | Standard |
| Charpy V-notch Impact | ≥ 27 J at -30 °C | Cold-weather service |
| Hydrogen Content | ≤ 0.4 mL / 100g | Low hydrogen |
| Available Diameters | 1/8″ (3.2), 5/32″ (4.0), 3/16″ (4.8), 7/32″ (5.6), 1/4″ (6.4 mm) | Lengths: 14″ / 18″ |
| Storage Temperature | 120–150 °C (250–300 °F) | Holding oven |
| Max Air Exposure | 4 hours | Per AWS D1.1 |
| Rebaking Cycle | 1 h @ 260–315 °C | Max 3 rebakes per lot |
| Current Range (AC/DC+) | 90–320 A | See rating per diameter |
Machinability, Tooling & Feeds
Deposited E7018 weld metal machines similarly to low-carbon steel (A36). The table below covers common post-weld operations.
| Operation | Tooling | Speed | Feed / Notes |
|---|---|---|---|
| Turning (facing) | Carbide C2 | 150–250 SFM | 0.008–0.015 IPR |
| Drilling | HSS / Cobalt | 60–80 SFM | Peck cycles |
| Tapping | Spiral point tap | 20–30 SFM | Sulfur-based cutting oil |
| Grinding (cleanup) | 36–60 grit Al₂O₃ / zirconia | 6000–8000 SFM | Disc wheels |
| Plasma / Oxy-fuel cutting | Standard equipment | Per base metal | Slag more tenacious than E6010/6011 |
| Carbon arc gouging | 5/16″ – 3/8″ carbon rods | 300–500 A | DC reverse polarity |
Common Defects & Quality Control
| Defect | Cause | Prevention / Corrective Action |
|---|---|---|
| Hydrogen-induced cracking (HIC) | Moisture in coating, improper storage, insufficient preheat | Store in holding oven, limit air exposure, preheat 50–150°C for thick sections |
| Slag inclusions | Improper interpass cleaning, excessive weave width | Clean thoroughly between passes; keep weave within 2.5× electrode Ø |
| Porosity | Arc blow, moisture, contaminated base metal | Control arc length, dry electrode properly, clean base metal (remove rust/oil/paint) |
| Undercut | Amperage too high, travel speed too fast | Reduce current, slow travel speed, use correct electrode angle |
| Lack of fusion | Low amperage, wrong angle, fast travel | Increase current, adjust work angle to 5–15°, reduce speed |
| Arc strikes (stray) | Careless handling outside weld zone | Always strike in joint; grind out any stray arc craters |
QC Checks: Visual inspection per AWS D1.1, dye penetrant / magnetic particle for surface cracks, UT or RT for volumetric defects. Fillet weld size measured by leg length and throat thickness. Acceptable porosity: max 1/8″ diameter per 1/8″ electrode, total length ≤ 3/4″ in any 6″ of weld. Hardness: max 350 HV for sour service (NACE MR0175).
Storage, Handling & Racking Guidelines
| Condition | Requirement | Action |
|---|---|---|
| Unopened cans | Indefinite shelf life if seal intact | Store dry, temperature-controlled environment |
| Opened containers | Transfer immediately to holding oven at 120–150°C | Do not expose to ambient air > 4 hours |
| Field use / portable | Use heated quiver (e.g. Phoenix DryRod) | Maintain low humidity on site |
| Rebaking | If exposed > 4 hours: 1 h @ 260–315°C | Max 3 rebakes per lot; label with rebake count |
| Racking & organization | Original containers or dedicated rod oven | FIFO rotation; do not mix diameters/brands without clear labeling |
| Canadian winter | Allow electrodes to warm to room temp before opening | Prevent condensation from cold-to-warm transition |
| SupplyGrid integration | Set reorder point at 2 weeks average consumption | Auto-generate PO when stock falls below 50 lb (22.7 kg) per diameter |