Plasma arc welding (PAW) — transferred vs. non-transferred arc, keyhole mode vs. melt-in mode, plasma torch geometry, orifice gas (argon), shielding gas, welding current, travel speed, energy input calculation, HAZ and microstructure, material compatibility (stainless steel, titanium, nickel superalloys), comparison to TIG/GTAW, plasma cutting parameters, and AWS D1.6 / D17.1 applications.
