GTAW NC II case studies
GTAW NC II · Put your knowledge to work in context.
Gas Tungsten Arc Welding (GTAW) NC II is a Philippine technical-vocational qualification for welders who produce precision TIG welds on carbon steel, stainless steel, aluminum, and other metals. It is typically pursued by entry-level welders, by SMAW or GMAW welders adding a precision process, and by workers in food, dairy, pharmaceutical, and fabrication shops where clean, contamination-free welds matter. The GTAW NC II case studies are 5 cases and about 3,401 words.
1Argon Accumulation in a Tank Compartment
You are the lead GTAW welder on a 12 m³ rectangular stainless steel tank compartment, 3 m long × 2 m wide × 2 m high, at a food plant. The only openings are a 500 mm entry hatch and a 100 mm vent at the top.
686 words, about 3 min2Drawing Note Conflict on a 304L Pipe-to-Flange Joint
A 6-in Schedule 40 304L pipe-to-flange joint must be welded to a drawing that shows a single-bevel groove weld, arrow side, all around, with a 37.5° bevel and a 3 mm root gap. The tail carries a “G” and the note reads “root, fill, and cap GTAW.” The project specification requires purge oxygen of 50 ppm or less and a WPS qualified for 304L.
715 words, about 4 min3Free-Iron Contamination on 304L Plate
You are preparing an 8 mm thick 304L stainless steel butt joint for GTAW. The only available 115 mm angle grinder has a carbon steel grinding wheel that was last used to bevel mild steel.
642 words, about 3 min4Aluminum Porosity, Smut, and Tungsten Spitting
A 6 mm thick 6061-T6 aluminum butt joint is being welded with AC GTAW using a 3.2 mm 2% zirconiated tungsten, 2.4 mm 4043 filler, 180 A, 60 Hz, 30% cleaning balance, and 15 CFH argon through a gas lens. The joint was cleaned with a stainless brush, but the filler rod has been lying open on the bench for two weeks.
668 words, about 3 min5Rejected Root Fusion, Expired Qualification, and Repair Limit
After final radiography of 24 welds on a 316L pipe spool, three butt welds show incomplete fusion at the root. The RT film and weld map are clear.
690 words, about 3 min