I85PREP
⌘ K
Red Seal Welder study materials
Red Seal Welder study resources

Red Seal Welder: Welding Processes and Equipment

Red Seal Welder · Work through your exam, one topic at a time.

All guide sections

Welding Processes and Equipment

Welding Processes and Equipment

This domain tests the principles, setup, and troubleshooting of SMAW, GMAW, FCAW, GTAW, SAW, and related equipment. Expect questions on polarity, transfer modes, shielding gas, electrode classification, and cause-and-effect troubleshooting.

Core rules

  • SMAW: flux-coated electrode provides shielding and slag. E4918 is a low-hydrogen electrode; keep it dry and follow storage/reconditioning rules. DCEP is common for general steel.
  • GMAW: continuous wire and gas. Short-circuit transfer suits thin sheet; spray transfer needs higher current and argon-rich gas; globular transfer is unstable. Keep contact-tip-to-work distance short and gas flow within the recommended range.
  • FCAW: tubular wire with flux. Self-shielded FCAW needs no external gas; gas-shielded FCAW usually uses CO2 or mixed gas. It gives high deposition and good penetration.
  • GTAW: non-consumable tungsten electrode. DCEN for steel and stainless; AC for aluminum to provide cleaning action; DCEP is rarely used because it overheats the tungsten. Use the correct tungsten type and grind longitudinally.
  • SAW: arc is buried under granular flux; high deposition, used on flat or horizontal positions. Flux must be dry and recovered properly.
  • Polarity matters: DCEP puts more heat into the workpiece; DCEN puts more heat into the electrode.

Worked example

A 6 mm aluminum plate is to be GTAW welded. The correct setup is AC, a clean tungsten electrode, a suitable aluminum filler such as 4043 or 5356, and mechanical removal of oxide just before welding. AC is chosen because the electrode-positive half-cycle breaks up the oxide while the electrode-negative half-cycle provides penetration and cools the tungsten. If DCEN alone were used, the oxide would be difficult to remove; if DCEP were used, the tungsten would overheat and contaminate the weld.

Traps

  • Using DCEP on GTAW steel and destroying the tungsten.
  • Setting gas flow by sound rather than a flowmeter.
  • Using the wrong wire for the base metal.
  • Forgetting to switch polarity for self-shielded versus gas-shielded FCAW.
  • Diagnosing porosity as “bad wire” when the cause is draft, moisture, or a leaking hose.