In this welding process, a special electrode that consists of metal wire which has bonded coating containing flux of desired gradients is used. The heat required for welding is generated by an arc between the flux covered consumable electrode and the workpiece. The process is shown in Figure 20.35. As the coating on the electrode melts and vaporizes, it forms a protective layer of gases that stabilizes the arc and protects. Flux also reacts with impurities of the metal and forms slug which floats on the surface of the molten metal and protects from contamination of atmospheric gases. After solidification the slug is chipped out from the weld.
Figure 20.35 Shielded Metal Arc Welding
Advantages
- The equipment required is simple, portable, and less expensive.
- Welds can be used in all positions.
Disadvantages
- The process has to change the electrode frequently due to consumable in nature.
- Low melting metals such as zinc, lead, and tin are not welded by SMAW.
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