MMAW NC I case studies
MMAW NC I · Put your knowledge to work in context.
The MMAW NC I (Manual Metal Arc Welding, Non-Certified Level I) is an entry-level knowledge assessment for people who want to demonstrate foundational understanding of manual metal arc welding and related processes before or alongside practical training. It is aimed at trainees, pre-apprentices, workshop assistants, and career changers who need a structured, theory-based benchmark rather than a trade certification. The MMAW NC I case studies are 5 cases and about 2,615 words.
1Confined-Space Tank Repair: Permit Versus Changing Atmosphere
A two-person crew is scheduled to repair a leaking seam inside a horizontal cylindrical tank at a food-processing plant. The tank is 2.1 m in diameter and 3.6 m long, with a single 450 mm manway; the interior is drained but a 20 mm layer of sludge remains.
604 words, about 3 min21045 Shaft Build-Up: Heat Input Within Limits but Preheat Ignored
A repair shop is rebuilding a worn bearing seat on a 1045 steel shaft, 60 mm diameter. The procedure calls for manual SMAW build-up with 3.2 mm E7018 electrodes at 130 A, 26 V, and 120 mm/min travel, using stringer beads.
496 words, about 2 min36G Pipe Root: Arc Blow and Incomplete Fusion at 4-6 O'Clock
A welder is producing a 168.3 mm OD x 7.1 mm wall pipe joint in the 6G fixed position. The root pass uses 2.5 mm E6010 at 85 A, and the fill uses 3.2 mm E7018.
525 words, about 3 min4GMAW Fillet Porosity: Draft, Worn Tip, and a Voltage 'Fix'
A fabrication shop is making 6 mm fillet welds on 10 mm mild steel brackets using manual GMAW. Parameters are 1.2 mm ER70S-6, 75% Ar/25% CO2, 210 A, 23 V, wire-feed speed 7.5 m/min, travel speed 350 mm/min, contact-tip-to-work distance 15 mm, and gas flow 15 L/min.
491 words, about 2 min5Radiograph With Clustered Porosity, Undercut, and a Possible Root Lack of Fusion
A 25 mm thick carbon steel butt weld, single-V, FCAW-G, is radiographed after completion. The film shows a 6 mm long cluster of rounded pores located 80 mm from the start of the weld, plus 1.2 mm of undercut on the cap along 150 mm.
499 words, about 2 min