What are the main welding processes and their differences?

The four main welding processes used in Quebec for QBQ exams are:

SMAW (Shielded Metal Arc Welding) — Manual arc welding with covered electrode:

• Advantages: Versatile, works on all steels, ideal for fieldwork and repairs
• Disadvantages: Slag to remove, slow speed, less productive
• Current: DC+ (reverse polarity) for most electrodes

GMAW (Gas Metal Arc Welding) — MIG/MAG welding:

• Advantages: Fast, clean, ideal for production
• Shielding gas: an argon-CO₂ mix for steel (the commercial mix known as “C25”), or pure CO₂ for economical use — the exact composition and flow rate are those on the gas supplier's data sheet and in the WPS
• Type: Short-circuit transfer (short arc) or spray transfer (spray arc)

FCAW (Flux Cored Arc Welding):

• Advantages: Deep penetration, ideal for thick steel, wind resistant (no external gas for self-shielded wire)
• Use: Heavy construction, structural frames, mining equipment

GTAW (Gas Tungsten Arc Welding) — TIG welding:

• Advantages: Precision, aesthetic quality, welding of non-ferrous metals (aluminum, stainless, magnesium)
• Disadvantages: Slow, requires high dexterity