Which Welding Rod for Structural Steel

Structural steel welding is governed by codes, primarily AWS D1.1 Structural Welding Code for buildings and AWS D1.5 Bridge Welding Code. The filler metal must meet the strength, toughness, and hydrogen requirements specified by the engineer. This is not a choose-what-you-prefer situation. The WPS dictates the filler.

Recommended Electrodes

E7018

The standard structural steel stick electrode. Low-hydrogen iron powder coating, 70 ksi tensile, smooth drag technique. Required by most structural WPS documents. Must be stored in a rod oven.

Tensile: 70k psi Common Size: 3/32" Amps: 65-100A
Full amperage chart and specs

E7018-1

Required when the WPS specifies impact testing at -20F. Identical to E7018 in operation. Mandatory for seismic applications (AWS D1.8) and cold-climate structural work.

Tensile: 70k psi Common Size: 3/32" Amps: 65-110A
Full amperage chart and specs

E71T-1

Gas-shielded flux-core for shop fabrication. Higher deposition rate than E7018 for production welding. Requires 75/25 Ar/CO2 or CO2 gas. Common in structural steel fabrication shops.

Tensile: 70k psi Common Size: .045" Amps: 150-300A
Full amperage chart and specs

E71T-8

Self-shielded flux-core for field erection. No gas required, works in wind. Seismic-rated for AWS D1.8. The standard wire for structural steel erection at height in the field.

Tensile: 70k psi Common Size: 0.045" Amps: 130-230A
Full amperage chart and specs

ER70S-6

MIG wire for structural welding in the shop. Used for lighter structural members, miscellaneous steel, and connections where flux-core is overkill.

Tensile: 70k psi Common Size: 0.023" Amps: 30-90A
Full amperage chart and specs

Technique Tips

Structural welding demands verified technique. Welders must be qualified to AWS D1.1 for the specific joint, position, and thickness range. Preheat requirements depend on the base metal grade, thickness, and ambient temperature. Interpass temperature maximums apply. Electrode storage and exposure time limits are code requirements, not suggestions.

For E7018, maintain a tight arc with consistent travel speed. The drag technique (pulling the rod) is standard. Listen for a consistent frying sound. If the arc sounds irregular, check your settings and arc length.

Common Mistakes to Avoid

Using non-low-hydrogen electrodes (E6013, E6011) for structural connections that require E7018. This is a code violation regardless of how the weld looks. Using E7018 that has been exposed to atmosphere beyond the allowed time limit. Welding in positions or on thicknesses outside your qualification range. Skipping preheat in cold weather.

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