Manual Metal Arc (MMA) welding, also known as Shielded Metal Arc Welding (SMAW), Flux Shielded Arc Welding or informally as stick welding is a manual arc welding process that uses a consumable electrode coated in flux to lay the weld. An electrode current in the form of either AC or DC from a welding power supply, is used to form an electric arc between the electrode and the metals to be joined. As the weld is laid, the flux coating of the electrode disintegrates, giving off vapors that serve as a shielding gas and providing a layer of slag, both of which protect the weld area from atmospheric containment.
Because of the versatility of the process and the simplicity of its equipment and operation, shielded metal arc welding is one of the world’s most popular welding processes. It dominates other welding processes in the maintenance and repair industry, and though flux-cored arc welding is growing in popularity, MMA continues to be used extensively in the construction of steel structures and in industrial fabrication. The process is used primarily to weld and steels (including stainless steel ) but aluminum, nickel and copper alloys can also be welded with this method