Arc welding processes are, by far, the most commonly used in the welding industry and are, therefore,
the main focus in this book. However, arc welding involves melting and most metals, when melted in
air, become contaminated with oxides and nitrides through contact with the oxygen and nitrogen in the
air. This contamination may result in a poor quality weld. Most arc welding processes have some
means of shielding (protecting) the molten metal from the air or some other means of removing the
harmful effects of oxygen and nitrogen. The two main methods of arc shielding are:
- flux shielding
- gas shielding