Shielded Metal Arc Welding (SMAW) is frequently referred to as “stick” or “covered electrode” welding. Stick welding is among the most widely used welding processes. The flux covering the electrode melts during welding. This forms the gas and slag to shield the arc and molten weld pool. The slag must be chipped off the weld bead after welding. The flux also provides a method of adding scavengers, deoxidizers, and alloying elements to the weld metal. When an arc is struck between the metal rod (electrode) and the workpiece, both the rod and workpiece surface melt to form a weld pool. Simultaneous melting of the flux coating on the rod will form gas and slag which protects the weld pool from the surrounding atmosphere. The slag will solidify and cool and must be chipped off the weld bead once the weld run is complete (or before the next weld pass is deposited).
The process allows only short lengths of weld to be produced before a new electrode needs to be inserted in the holder. Weld penetration is low and the quality of the weld deposit is highly dependent on the skill of the welder.
Process characteristics of Shielded Metal Arc Welding (SMAW/Stick)
Uses a electrode rod that is quickly consumed,
Uses equipment that is simple, inexpensive, and highly portable,
Uses an electrode that provides and regulates its own flux,
Provides all position flexibility,
Is less sensitive to wind or drafts,
Yields a weld with a variable quality and appearance based on operator skill,
During the SMAW welding process the arc is established, the flux coating on the rod disintegrates and then forms a gas that shields the weld from the atmosphere. The slag that is produced by the flux coating prevents the weld metal from oxidizing.Equipment required to perform the SMAW welding process includes a constant current power source that supplies the power to the consumable rod electrode.The SMAW welding process typically is capable of producing three types of welded joints. They are:
Lap joint, and
The illustration below shows these three common welded joints.