Uses a wire called a ‘consumable’ which is fed automatically into the molten weld pool at the weld seam covered by a sand like flux. It is a machine / workshop welding process used for heavy plate welding on long, circumference and large nozzle seams.
Uses a thinner consumable than SAW, which is fed into the weld pool automatically and protected by an inert gas instead of a flux. It is used on nozzle to shell, neck to flange & attachment welding. This hand welding process is normally only done in workshop environments because it relies on the inert gas to shield the molten pool of metal from the air.
This is basically the same as MIG except if can be used to put in a ‘root run’ which is the first ‘pass’ in a weld seam when coming from one side only, being able to put in a root run consistently is the difference between a good welder and an average one, it is a differentiator.
GTAW uses a hand-held torch with tungstate electrode to transfer the electrical energy (heat) into the weld seam, a wire is then fed into the molten weld pool by hand – there is an art to this process. This is a slow high heat welding process providing an aesthetic looking weld. It also uses an inert gas to protect the molten pool and is often used to put in a ‘root run’ which is then ‘capped’ with MIG to fill the remaining joint.
Usually called ‘stick welding’, MMA uses a flux coated electrode. It is used on site because it’s suitability of the works and is not affected by wind.