Structural Plate vs. Pressure Piping Certifications
In the welding profession, credentials are proof of capability under code-governed stress. While hobbyists weld on benches, certified structural welders and pipe hands weld in tight trenches, overhead beams, and sub-zero weather following strict WPS (Welding Procedure Specifications).
1. AWS D1.1 Structural Steel (Plate Qualification)
The American Welding Society (AWS) D1.1 standard governs steel buildings, bridges, and infrastructure:
- Test Positions: 1G (flat), 2G (horizontal), 3G (vertical up), and 4G (overhead). Passing 3G and 4G combination qualifies the welder for all plate positions.
- The Coupon: 3/8-inch or 1-inch A36 steel plate with a 45-degree included bevel angle, 1/4-inch steel backing strip, and 1/4-inch root opening.
- Processes Tested: Shielded Metal Arc Welding (SMAW with E7018 low-hydrogen electrodes) or Flux-Cored Arc Welding (FCAW-G E71T-1 dual shield).
- Inspection Protocol: Visual examination for undercut under 1/32-inch, zero porosity, and two side bend tests bent 180 degrees over a mandrel. Zero fissures exceeding 1/8-inch allowed.
2. The Holy Grail: ASME Section IX 6G Pipe Test
The 6G pipe test is considered the ultimate test of manual dexterity and heat control:
- Orientation: Schedule 80 carbon steel pipe positioned at a 45-degree angle without rotating. The welder must continuously adjust torch angle and body posture from flat to vertical to overhead.
- Open Root Technique: SMAW with E6010 cellulosic electrode downhill/uphill root pass (keyhole control), followed by hot pass, fill passes, and cap with E7018 low-hydrogen rod.
- Non-Destructive Testing (NDT): 100% radiographic examination (X-ray) or 4 guided root and face bends. Any slag inclusion, lack of fusion, or internal suck-back results in immediate failure.
3. Rig Welder & Traveling Pipeline Economics
Welders who own their mobile welding rig (custom truck equipped with a Lincoln Vantage or Miller Big Blue diesel generator, leads, oxy-acetylene torch, and beveler) operate as independent subcontractors:
- Single Hand (W-2 Employee): $32 – $48 / hr + per diem.
- Rig Welder (Truck + Arm): $85 – $120 / hr billable + $150 – $220 / day non-taxable per diem.
- Annual Earning Range: $130,000 – $185,000 during active pipeline turnaround or refinery maintenance seasons.