Which Welding Rod for Pipe: Root, Fill & Cap
Top pick: E6010, starting at 40-80A on DCEP. 4 rods compared with settings for this application.
Safety-critical application. Pipe welding often falls under ASME or AWS code requirements. Rod selection, WPS, and welder qualification must comply with the governing code for your application.
Pipe welding uses different rods for different passes. The root pass burns through the gap between pipe ends and must achieve full penetration. Fill and cap passes build strength and appearance on top of the root. Using the wrong rod on the wrong pass is the most common pipe welding failure.
Best Rods for Pipe Welding
E6010
The standard root pass rod for carbon steel pipe. Deep-penetrating cellulose flux burns through root gaps on open butt joints. DCEP only. The rod every pipeline welder learns first.
E7018
Fill and cap passes on carbon steel pipe. Low-hydrogen flux produces code-quality welds at 70,000 psi tensile. Smooth arc and easy slag removal for clean cap beads. DCEP preferred.
ER70S-6
MIG root on shop pipe under 4 inch diameter with backing gas. Faster than stick but limited to clean steel in controlled conditions.
E71T-1
Flux-core fill for production pipe welding in shop. Gas-shielded with 75/25 Ar/CO2. High deposition rates for thick-wall pipe.
Quick Amperage Reference for Pipe Welding
| Electrode | Polarity | Common Size | Amps | Full Chart |
|---|---|---|---|---|
| E6010 | DCEP | 1/8" | 75-130A | E6010 chart |
| E7018 | DCEP / AC | 1/8" | 90-160A | E7018 chart |
| ER70S-6 | DCEP | 0.035" | 50-220A | ER70S-6 chart |
| E71T-1 | DCEP | .045" | 150-300A | E71T-1 chart |
Pipe Welding Technique
Root pass with E6010: maintain a tight keyhole at the leading edge of the puddle. If the keyhole closes, you are moving too fast or running too cold. If it opens too wide, reduce amperage or slow down.
Fill passes with E7018: use stringer beads, not weave. Each pass should overlap the previous by half the bead width. Clean slag completely between passes.
Cap pass: slight weave acceptable to tie into both toes. Do not weave wider than 2.5 times the rod diameter.
Which Rod for Your Situation
Equipment You Need
Minimum 200A DC stick welder for pipe. 250A+ preferred for 5/32 inch E7018 on schedule 80.
Mistakes to Avoid With Pipe Welding
Using E7018 for root passes. E7018 cannot burn through the root gap on an open butt joint. The result is lack of fusion defects that fail X-ray. Use E6010 for the root.
Running E6010 for fill passes. E6010 has high spatter, rough bead appearance, and only 60,000 psi tensile. E7018 produces cleaner, stronger fill passes.
Wrong rod diameter for pipe wall thickness. Use 3/32 inch E6010 for root passes on schedule 40 and thinner. 1/8 inch for schedule 80 and heavier.
What Goes Wrong
A fabrication shop used E7018 for all passes on schedule 40 pipe including the root. The low-hydrogen rod could not burn through the 1/16 inch root gap. X-ray revealed lack of fusion on 4 of 6 joints. All four were cut out and rewelded with E6010 root, E7018 fill.
Pipe Welding: Common Questions
What rod for a pipe root pass?
E6010 on DCEP. The cellulose flux produces a forceful, deeply penetrating arc that burns through root gaps. Use 3/32 inch diameter at 60-80A for schedule 40, 1/8 inch at 75-95A for schedule 80 root passes. Higher amperage (100-130A) is for fill and cap passes only. See the full E6010 amperage chart for per-diameter settings by position.
Can you use E7018 for a root pass on pipe?
Not on open root joints. E7018 has a smooth, low-penetration arc designed for fill and cap passes. It cannot burn through the root gap reliably, causing lack of fusion defects that fail X-ray. The E6010 vs E7018 comparison explains why these two rods are partners, not substitutes.
What amps for 6G pipe welding with E6010?
3/32 inch E6010 at 60-80A for the root pass. Start at 70A and adjust based on keyhole size. Fill passes with 1/8 inch E7018 at 100-140A. Reduce 10-15A for overhead sections. For position-specific amperage adjustments, see the welding position guide.
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Reference data only. Verify all settings against manufacturer documentation and the applicable welding code before use. Amperage ranges are starting points that vary by position, fit-up, and material. Welding involves serious injury risks including burns, electric shock, fume exposure, and fire. This site does not replace proper training, certification, or employer safety procedures. See full terms of use.