If you’ve spent any time around welding shops, construction sites, or fabrication yards, you’ve likely heard of—or used—the E7018 electrode. Often called the “low-hydrogen” or “stick electrode of choice” for critical welds, it’s a staple in the toolkit of structural welders, pipeline welders, and anyone needing strong, ductile welds on carbon steel.
But what exactly makes this rod so popular and trusted? In this complete guide, we’ll break down everything you need to know: from its classification and characteristics to its best applications, tips for use, and common challenges.
Understanding the Code: What Does “E7018” Mean?
The American Welding Society (AWS) numbering system tells you almost everything you need to know right on the rod’s coating.
- E: Stands for Electrode.
- 70: Indicates the minimum tensile strength of the weld metal. In this case, 70,000 pounds per square inch (psi).
- 1: This number tells you the welding position the rod can be used in. “1” means it’s an all-position electrode (flat, horizontal, vertical, overhead).
- 8: The final digit is the most important. It specifies the type of coating and the welding current.
- A coating of iron powder & low-hydrogen compounds.
- Suitable for AC or DC+ (reverse polarity) current.
Key Takeaway: You’re looking at an all-position, low-hydrogen electrode that produces welds with 70,000 psi tensile strength using AC or DCEP current.
Key Characteristics & Advantages of the E7018
1. Low Hydrogen Content
This is its superpower. The coating is specially designed to minimize moisture absorption, which prevents hydrogen-induced cracking (HIC)—a major concern in thick materials, high-strength steels, and restrained joints.
2. Excellent Weld Quality
E7018 produces smooth, clean welds with a fine ripple pattern, often described as “stacked dimes” in vertical-up welds. Slag removal is relatively easy.
3. High Ductility and Impact Resistance
The weld deposit has good elongation (ductility), meaning it can flex and bend without breaking. It also maintains notch toughness at lower temperatures, making it ideal for structures subject to stress or cold environments.
4. High Deposition Efficiency
The coating contains iron powder (typically 25-40%), which adds to the weld metal. This means you lay down more metal per rod compared to a non-iron powder electrode (like an E6010), improving speed and efficiency.
5. Smooth Arc & Minimal Spatter
It has a stable, medium arc with very little spatter, leading to less cleanup time and a neater weld bead.
Common Applications: Where Is E7018 Used?
Because of its strength and reliability, the E7018 is the go-to rod for many critical welding jobs:
- Structural Steel: Buildings, bridges, and I-beams.
- Shipbuilding & Offshore Rigs
- Pressure Vessels & Pipelines (especially for the “hot pass” and fill/cap passes)
- Heavy Equipment Repair
- Carbon Steel Welding where high strength and crack resistance are needed.
- Welding on thicker sections and highly restrained joints.
How to Weld with E7018: Tips & Techniques
Storage is CRITICAL!
- Always store E7018 rods in a heated electrode oven (typically 250°F – 300°F / 120°C – 150°C) if the original sealed container has been opened.
- Why? The low-hydrogen coating absorbs moisture from the air. Moisture introduces hydrogen into the weld, defeating the rod’s primary purpose and risking cracking.
- Portable rod ovens are essential for job sites. If a rod is exposed to air for more than 4 hours (check manufacturer specs!), it must be reconditioned in a holding oven.
Machine Setup & Polarity
- Preferred Current: DC+ (DC Reverse Polarity). This provides the most stable arc and best bead appearance.
- Alternative Current: AC. Use this if you only have an AC welder (like a transformer-style buzz box). The arc may be slightly less smooth.
- Do NOT use DC- (DC Straight Polarity).
Welding Techniques
- Arc Length: Maintain a very short arc. The coating is designed to contact the workpiece (“drag” or “contact” technique), especially in flat and horizontal positions.
- Angle: Use a slight drag angle (around 5-15 degrees) in the direction of travel.
- Motion: A steady, consistent travel speed with minimal manipulation is often best. For wider beads, a slight side-to-side weave can be used.
- Vertical Up: It excels at vertical-up welding. Use a triangular or “Z” weave pattern, pausing at the edges to prevent undercut and ensure proper fusion.
Challenges & Limitations
- Moisture Sensitivity: Its greatest strength is also its greatest weakness. Improper storage ruins the rod.
- Poor Penetration Profile: Compared to a “digging” rod like the E6010, the E7018 has a gentler, more fluid arc. It’s not the best choice for poor fit-up, rusty metal, or deep penetration needs on the root pass of an open-root joint. Many welders use E6010 for the root and E7018 for fill and cap passes.
- Requires Clean Metal: While not as fussy as some rods, it works best on clean, rust-free, paint-free, and oil-free steel.
Frequently Asked Questions (FAQ)
Q: Can I use E7018 for everything?
A: No. It’s not ideal for dirty, rusty metal or open-root joints where deep penetration is key. It’s a quality rod for quality work on prepared materials.
Q: What’s the difference between E7018 and E7018-1?
A: The “-1” designation (e.g., E7018-1 H4R) indicates enhanced impact toughness at lower temperatures, making it suitable for cryogenic or Arctic applications.
Q: E7018 vs. E6013 – which is better?
A: E6013 is an easy-to-use AC rod for light fabrication, thin metal, and hobbyist work. E7018 is stronger, more ductile, crack-resistant, and is used for structural and critical work. They are in different leagues.
Q: How do I know if my rods are bad?
A: If they’ve been out of the oven too long, you may notice difficulty striking an arc, excessive spattering, a porous weld bead, or steam coming from the coating during welding. When in doubt, re-bake them.
Conclusion
The E7018 is more than just a welding rod; it’s a symbol of quality and reliability in the welding industry. Its low-hydrogen properties, combined with excellent strength and ductility, make it the trusted choice for welding where failure is not an option—from skyscrapers to pipelines.
Mastering the E7018 requires respect for its storage needs and practice with its technique. But for any welder looking to tackle serious fabrication, structural work, or critical repairs, becoming proficient with this electrode is an essential skill. Grab your rod oven, set your machine to DC+, and start practicing those smooth, strong beads.