E7018 — What It Is and Why It Matters
E7018 is the most widely specified stick welding electrode in structural steel fabrication. It is a low-hydrogen, basic-coated rod that produces strong, ductile, crack-resistant welds with excellent mechanical properties — making it the standard for code work under AWS D1.1, ASME, and other structural specifications.
The designation means: E (electrode), 70 (70,000 PSI tensile strength), 1 (usable in all positions), 8 (low-hydrogen iron powder coating, AC or DCEP). The low-hydrogen flux coating produces a smooth, quiet arc with heavy slag coverage and minimal spatter.
E7018's critical requirement is moisture control. The low-hydrogen flux absorbs atmospheric moisture, and trapped moisture introduces hydrogen into the weld — the primary cause of hydrogen-induced cracking in structural steel. Opened containers of E7018 must be stored in a heated rod oven at 250-300°F. Rods exposed to ambient air for more than a few hours should be recondititioned (re-baked) per the manufacturer's instructions before use.
Frequently Asked Questions
Why is E7018 called low-hydrogen?
The basic flux coating is formulated to produce very low levels of diffusible hydrogen in the weld deposit — typically under 8 mL per 100g. Hydrogen in the weld causes delayed cracking (cold cracking), especially in thick, high-strength, or restrained joints. The low-hydrogen chemistry directly addresses this failure mode.
Can E7018 be used on DC only?
No — E7018 runs on both AC and DCEP (DC electrode positive). DCEP provides a slightly smoother arc and deeper penetration. AC capability makes E7018 usable on transformer-based buzz box welders that only output AC. DCEP is preferred when available.